Choosing & Using Binoculars: A Guide for Star Gazers, Birders and Outdoor Enthusiasts [1 ed.] 9783031447099, 9783031447105

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Neil T. English

Choosing & Using Binoculars A Guide for Star Gazers, Birders and Outdoor Enthusiasts

Choosing & Using Binoculars

Neil T. English

Choosing & Using Binoculars A Guide for Star Gazers, Birders and Outdoor Enthusiasts

Neil T. English Fintry, Glasgow, Scotland, UK

ISBN 978-3-031-44709-9    ISBN 978-3-031-44710-5 (eBook) https://doi.org/10.1007/978-3-031-44710-5 © Crown 2024, Corrected Publication 2024 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Paper in this product is recyclable.

Foreword

Which binocular enthusiast has never been in this situation: Restlessly searching for a new binocular while being hopelessly confused by the enormous variety of models he has just dug up on the Internet, and by their contradictory reviews, created by observers of most diverse backgrounds, demands and habits. With this book, Choosing & Using Binoculars: A Guide for Star Gazers, Birders and Outdoor Enthusiasts, Dr Neil English has succeeded in a most sovereign manner in bringing order into the chaos. Binoculars from all price ranges and produced for every conceivable field of application are systematically presented and analyzed, often accompanied by field reports compiled during daytime observations or under the starry sky. Moreover, these reports are composed by an author who has decades of experience with optical instruments and written numerous articles for the magazines Astronomy Now and Birdwatching, not to mention the books he has authored in the field of amateur astronomy. This book begins with a short but systematic introduction to binoculars, to provide the novice with a basis from which he can gain knowledge in the chapters to come. After an interesting outline of the history of binoculars, several rather extensive chapters follow, in which binoculars in numerous fields of applications are discussed. At this point even the most experienced binocular connoisseur gets his money’s worth, and I readily admit that as a veteran binocular geek, I have encountered plenty of models here for the first time. In the next part, the book alters its perspective and now the manufacturers or distributors of binoculars with their most important product lines are presented. This section offers the reader an opportunity to gain insight into the different product philosophies of these manufacturers. After useful accessories for binocular observation have been introduced, a highly instructive practical chapter follows, which is dedicated to the testing of binoculars in the field, and which reflects the author’s vast experience with visual optical instruments. Here also the optical aberrations and the systematic tests which lead to their discovery are included. The work is rounded out with a very insightful selection of top bargains, followed by a selection of further binocular literature and a delightful exhibition of selected classic binoculars.

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Foreword

I consider the existence of this book a fortunate circumstance. Never before has such an extensive overview of the binoculars on offer been compiled in such a professional manner. With its many supplementary chapters, it is a fascinating read for the beginner as well as for the experienced scholar. Those who are lucky owners of this book may feel urged to do what Dr English recommends in Chap. 31, which I regard a concluding highlight of this work: Go outside, equipped with a binocular, with this book and perhaps a deck chair, and enjoy the beauty and tranquility of nature! Dresden, Germany

Holger Merlitz

The original version of the Acknowledgement has been revised. It was inadvertently published with the erroneous statement that the magnification of Celestron Granite binoculars is 9×33. The correct magnification is 7×33. The revised version is now available with the corrected information.

Acknowledgements

A book of this magnitude of undertaking could not have been achieved in a vacuum. Very special thanks are given to Paul Wehr, who kindly shared his knowledge of many contemporary and classic binoculars with me and who contributed a great piece on the perennially loved Swift Audubon binoculars of yesteryear. A big thank you also to Gary Murphy, who kindly lent me his Celestron Regal ED 8×42 for evaluation and also for contributing his knowledge and experiences with many Canon IS binoculars. My gratitude is also extended to Dr Holger Merlitz, a wonderful scholar and friend to the binocular community with his erudite technical knowledge of binocular optics and his boyish enthusiasm for sharing his experiences with others. He kindly read some of the chapters of an early draft of the manuscript and provided some very constructive feedback on its content. He also wrote a wonderful short review of the Leica Retrovid 7×35 for me, which I’m very grateful for. I’ve also enjoyed many helpful discussions on all things binoculars with my former student and friend, Joe Stearn, whose observations have been very enlightening. My thanks are also extended to Richard Duff, for sharing his thoughts on his world-class Fujinon binoculars, Philip Grimsey, a keen British birder who provided his thoughts on the Celestron Granite 7×33, as well as for his interesting conversations about classic binoculars, and Rob Nurse who kindly provided his opinions on the Olympus DPSI binocular. Thanks are also extended to David Laughlin who kindly provided his opinions on the Athlon Cronus 8.5×42. A special mention of thanks is also extended to Steve Graham, Director of First Light Optics, who kindly supplied a number of binoculars to me for testing and evaluation. Gratitude also to Henrik Rundgren, Chuck Hill, Sam Shepherd and John Magera for providing binocular images used in the book. I would also like to thank Rich V, based in Nevada, for interesting discussions on the Nikon E II 10×35. A big shout out to Michael Maimone, my editor at Springer Nature, for engaging so enthusiastically with the book content and offering many helpful suggestions about its layout. And finally, I would like to graciously thank my wife Lorna and my sons for their support as I pursued this project to its conclusion. Your patience and love are inspirational!

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Introduction: The Joy of the Binocular

The author’s Nikon E II 8×30. All images credited to the author unless otherwise stated Oh, my dear little 8×30, Thou art a wonder to behold, A tool of great utility, A treasure worth more than gold. Thou bringest to me a world of sights, That my eyes would never see, A world that's full of beauty, And of endless mystery.

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Introduction: The Joy of the Binocular Thou revealest the majesty Of the soaring bird in flight, The grace of the running deer, And the power of nature's might. Through thy lenses I see, A world that's full of life, A world that's full of wonder, And of endless beauty rife. Oh, my dear little 8×30, Thou art a precious gem to me, A companion on my journey, And a portal to my dreams to be. May thy lenses always be bright, And thy magic never fade, May thou continue to bring, A world of wonders unafraid. So here's to thee, my dear companion in sight, May thou always be by my side, And may thy little frame forever lend, A view of the world so wide.

Binoculars are life-enhancing instruments. They bring joy to so many people. By magnifying distant objects, binoculars help us observe wildlife in their natural habitats and appreciate the beauty of landscapes that would otherwise be out of reach. Birdwatching is a popular activity that requires the use of binoculars, and it allows people to observe and appreciate the incredible diversity of bird species around the world. At night, binoculars allow us to peer more deeply into the universe in all its glory, bringing myriad faint stars, galaxies, and nebulae into view. Whether it's attending a sports event, a concert, or a theatrical performance, binoculars can significantly enhance the experience. By magnifying the action on stage or the field, binoculars allow us to see the details that we would otherwise miss, and thus enhance our enjoyment of the event. Binoculars also allow people to explore new and exciting places, such as mountains, deserts, and oceans. By magnifying distant landscapes and wildlife, binoculars make it possible to appreciate the beauty and wonder of these places and inspire us to explore even further. Binoculars can also create a sense of discovery and excitement. The ability to see things that are usually hidden from view can provide a sense of wonder and awe, which can be incredibly satisfying and uplifting. They provide a sense of connection to the world around us. By allowing us to observe wildlife, landscapes, and events, binoculars help us to appreciate the interconnectedness of all things and our place in the world. Binoculars are complex optical instruments that use lenses and prisms to magnify distant objects and make them appear closer. The newcomer to the world of binoculars will quickly become inundated by the number of models in today’s market, making it almost impossible to see the woods for the trees. But just like shoes, one size doesn’t fit all. Some are ideal for travel, others are better suited to detailed

Introduction: The Joy of the Binocular

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nature observation, and still others are designed to study the night sky. But how do you choose? And what attributes make for a good binocular? How good a binocular will you need if you’re just looking out from a window at a birdfeeder in your back garden? In this book, you’ll find the answers. We shall explore together the fascinating world of binoculars; their optical properties, their various formats and the strengths and weaknesses inherent in choosing a model that best meets your needs and expectations. Although I’ve been a keen amateur astronomer since childhood, you may be surprised to learn that I’m a latecomer to the world of binoculars. You see, I never embraced the philosophy that many astronomy authors were promulgating in the books I read in my youth; that the best instruments to learn the sky with were binoculars and not telescopes. I went straight to the latter, and so it remained for many decades. During the COVID lockdowns, however, with more time on my hands, I kindled a very strong interest in binoculars which led me to explore, test, and evaluate many different models from different brands. This collective knowledge has found its way into this book, where I give my honest opinions on binoculars in different price classes. They say you get what you pay for. That’s largely true, but like everything else in life, there are always exceptions. Today, you can buy excellent quality gear at prices that won’t break the bank, and in this book I’ll be highlighting several models from each genre that represent exceptional value for money in today’s market. What’s more, you can achieve a great deal using very modest instruments – it’s all about your attitude! While the modern binocular market is flooded with the newer roof prism models, the reader will learn that the old-school Porro prism binoculars enjoy many advantages over the former. Indeed, the author has given roughly equal weight to both these types of binoculars to help redress the unmerited bias in the contemporary market to promote the sales of roof prism models. Furthermore, the reader will soon learn the many reasons why this author prefers Porro prism binoculars over their roof prism counterparts. You will also learn about some terrific models from the past – models that serve up fields of view so wide that they’d make even the most impressive contemporary wide-angle models feel rather ordinary! A brief note on terminology. I refer to binoculars in the singular, that is, “a binocular.” It’s grammatically incorrect to use the phrase “a pair of binoculars,” as the word “binocular” is a collective noun implying two telescopes mounted side by side. If you’re offended by this choice of wording, then I apologize in advance. The first part of the book begins by exploring many of the technicalities of modern binoculars, as well as a brief overview of their history. Following this, we explore the major formats on the binocular market today including small pocket-­ sized instruments, compact formats, full-size instruments, and more specialized low-light binoculars, discussing their relative strengths and weaknesses. We also take a whistle-stop tour of the various kinds of binoculars best suited for stargazing, observing in the marine environment, range-finding, and image-stabilized models.

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Introduction: The Joy of the Binocular

The reader will forgive the author if his/her favorite binocular brand is not mentioned in the text. Because the market has so many models, it’s well-nigh impossible to have evaluated them all. Moreover, because many binoculars available today, especially in the low- and mid-priced market, are clones of each other, the chances are good that an evaluation of one brand is probably representative of many others on the market. The second part of the book is dedicated to exploring the main binocular manufacturers and their product lines, as well as discussing the many accessories used by binocular enthusiasts. It also includes a chapter on how to test binoculars and what those tests reveal about your instrument. We explore a series of classic models that have totally surprised this author in regard to optical and ergonomic performance and which offer a glimpse of what the future of binoculars may look like! Finally, the book winds up with a passionate call for binocular enthusiasts to get out and about and use their binoculars to explore nature in all its glory, whether on earth or in the skies above. After all, that’s what your binoculars were designed for! Fintry, Scotland, UK 

Neil T. English

Contents

Part I A Survey of the Binocular Market 1

Binoculars 101������������������������������������������������������������������������������������������    3

2

A Brief History of the Binocular������������������������������������������������������������   27

3

Pocket Binoculars������������������������������������������������������������������������������������   31

4

Compact Binoculars��������������������������������������������������������������������������������   83

5

Full Size Binoculars ��������������������������������������������������������������������������������  149

6

Low Light Binoculars������������������������������������������������������������������������������  217

7

Range-Finding Binoculars����������������������������������������������������������������������  233

8

Astronomical Binoculars ������������������������������������������������������������������������  247

9

Marine Binoculars ����������������������������������������������������������������������������������  299

10 Image Stabilized Binoculars�������������������������������������������������������������������  313 Part II Binocular Companies, Classic Instruments, Accessories and More 11 Leica Binoculars��������������������������������������������������������������������������������������  329 12 Zeiss Binoculars ��������������������������������������������������������������������������������������  339 13 Swarovski Binoculars������������������������������������������������������������������������������  345 14 Nikon Binoculars��������������������������������������������������������������������������������������  351 15 Vortex Binoculars������������������������������������������������������������������������������������  359 16 GPO Binoculars ��������������������������������������������������������������������������������������  363 17 Opticron Binoculars��������������������������������������������������������������������������������  367 18 Meopta Binoculars ����������������������������������������������������������������������������������  371 xiii

xiv

Contents

19 Maven Binoculars������������������������������������������������������������������������������������  375 20 Kowa Binoculars��������������������������������������������������������������������������������������  379 21 Pentax Binoculars������������������������������������������������������������������������������������  385 22 Oberwerk Binoculars������������������������������������������������������������������������������  389 23 Leupold Binoculars����������������������������������������������������������������������������������  393 24 Fujinon Binoculars����������������������������������������������������������������������������������  397 25 Bushnell Binoculars ��������������������������������������������������������������������������������  401 26 Popular Binocular Accessories����������������������������������������������������������������  405 27 Testing Binoculars: Notes from the Field����������������������������������������������  417 28 Top Bargains in Today’s Market������������������������������������������������������������  431 29 A Brief Survey of Classic Binocular Literature������������������������������������  441 30 Classic Binoculars������������������������������������������������������������������������������������  461 31 Earth and Sky������������������������������������������������������������������������������������������  503 Correction to: Binoculars 101������������������������������������������������������������������������  C1 Binocular Repairs and Restorers�������������������������������������������������������������������  515 Glossary������������������������������������������������������������������������������������������������������������  517 Index������������������������������������������������������������������������������������������������������������������  519

Part I

A Survey of the Binocular Market

Chapter 1

Binoculars 101

A prospective buyer unacquainted with binoculars will likely quickly become inundated with the number of makes and models on the market. Some have funny Z shaped anatomies, others look like opera glasses, where the objectives are in-line with the eyepiece lenses. Some are tiny, fitting in the palm of one’s hand, while others are enormous and heavy, requiring a substantial mount to do them justice. You’ve probably been daunted too by the huge range in their price ranges, with the cheapest coming in at $10 or $15, while other brands, sporting binoculars that outwardly look the same as those cheap instruments command price tags in excess of $2000. How can we even begin to make sense of the enormous numbers of models available today? A good place to start is to briefly explain the basic features of all binoculars before delving into a more detailed discussion about the major differences between modern binocular designs. The vast majority of binoculars used for recreational purposes and surveillance come in two flavors; either Porro prism or roof prism binoculars. Porro prism binoculars are probably the kind most familiar to the public. Indeed, if one were to stop someone at random on a busy high street and ask them to identify a binocular, chances are they would point to a Porro-prism model, characterized by its zig-zag shape. Roof prisms are often smaller, more streamlined, and more compact, with both its barrels being straight.

The original version of the chapter “Binoculars 101” has been revised. A correction to this chapter can be found at https://doi.org/10.1007/978-3-031-44710-5_32 3 © Crown 2024, Corrected Publication 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_1

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1  Binoculars 101

Two binocular designs: a Porro prism instrument (left) and roof prism model (right)

All binoculars, whether Porro or roof prism types, are adorned with two numbers. For example, 8×30, 10×42 or 12×50. The first number indicates magnification while the second number indicates the aperture of the front-end (objective) lenses. Thus, an 8×30 instrument magnifies 8 times and has objective lenses with diameters of 30 mm. A 12×50 has a magnification of 12 and objectives that are 50 mm across, etc. Most binoculars also state the field of view that can be seen by the observer. This is usually expressed in feet at 1000 yards (or meters at 1000 m in Europe). For example, a binocular that sports a field of view of 350 feet at 1000 yards means that you will be able to see 350  feet from one edge of the image to the other when viewed from a distance of 1000 yards. Alternatively, in Europe, field of view is more commonly expressed in the number of meters visible at a distance of 1000 m. More on this topic later in the chapter. In general, the lower the magnification of the binocular, the wider the apparent field of view.

Antireflection Coatings

5

Antireflection Coatings

Lens blooms from the application of antireflection coatings

Perhaps you’ve noticed a strange blue, green or purple bloom on the surface of your binocular lenses. These are called anti-reflection coatings, which greatly boost the amount of light passing through the binocular and help eliminate annoying internal reflections. Uncoated optical glass reflects 4% of the light that hits its surface, meaning that 96% passes through (actually a bit less than this as some light is absorbed by the glass as well). A typical binocular has between 6 and 10 lenses and prisms, each having two surfaces. Now, 4% light loss doesn’t sound especially large until you do the math which considers the total light transmitted. If only 96% passes through each of say 20 glass surfaces, then the total light transmitted will be 0.96 raised to the power of 20 which results in 0.442, that is, only 44.2% of the light gathered by the objectives reaches your eyes. Put another way, more than half of all the light gathered by the binocular will be either scattered or reflected away, drastically reducing both image brightness and contrast. Thankfully, modern anti-reflection coatings greatly increase light transmission and reduce light loss from internal reflections and light scatter. They work by causing selected wavelengths of light to destructively interfere with each other. Fully coated optics usually have a single layer of magnesium fluoride applied to each glass surface but all decent modern binoculars are either multicoated (possessing 2 layers of antireflection coatings) or fully broadband multi-coated, having up to 8 layers of coatings vacuum deposited on the surfaces of all the lenses and prisms ensuring progressively higher light transmissions of the order of 80–95+%.

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1  Binoculars 101

Antireflection coatings work via a process called thin layer interference of light waves being reflected off materials of different refractive indices. The refractive index, often symbolized by the letter ‘n’. tells you how much a light ray changes direction as it leaves one medium and enters another. The greater the refractive index, the greater the degree of light bending that takes place. The refractive index varies from 1.0 for air or a vacuum to greater than 2 for some transparent materials. For example, water has a refractive index of 1.3 and ordinary window glass has a larger refractive index of 1.5. Other transparent materials like diamond, Perspex, and transparent polycarbonate materials have their own unique refractive index. Now when light waves reflect off a surface with a higher refractive index than the medium they have been travelling through (air to glass for example), they undergo a phase change of 180 degrees (pi radians). Conversely, when light waves reflect off a surface with a lower refractive index (glass to air for example), they do not undergo a change of phase.

nair

ncoating

II. θ2

d

nglass

How antireflection coatings work. Light waves reflected off the top and bottom of the coating destructively interfere with each other and so cancel each other out so long as the path difference between the waves is 180 degrees. The thickness of the coating determines the wavelength of light eliminated. (Image Credit: Wiki Commons)

By applying a coating with a certain thickness, optical engineers can cause the ray reflected off the top and the bottom of the coating to merge and undergo so-­ called destructive interference, thereby cancelling themselves out. Since green light (wavelength of ~550 nm) is the color the human eye is most sensitive to, optical designers preferentially aim to cancel these rays when light reflects off optical surfaces, resulting in the reflection of much dimmer red and blue wavelengths, which we perceive as a purple lens bloom. The thickness, d, of the coating determines the color of light that is cancelled by interference according to the equation:



d  minimum  

 4n

Exit Pupil Considerations

7

where λ is the wavelength of light undergoing destructive interference and n is the refractive index of the coating. It turns out that if we use a common material such as magnesium fluoride to cancel out light in the middle of the visible spectrum, the coating will have to have a minimum thickness of about 100 nm. By applying multiple layers to the lens surfaces, reflections are brought to a minimum and light transmission is optimized.

Exit Pupil Considerations If you hold your binoculars up to the light and look at the eyepieces, you’ll see two small circular shafts of light. This is known as the exit pupil. The size of the exit pupil will vary from model to model, and usually falls within the range of 2 mm all the way up to 7 mm. To calculate the size of the exit pupil on your binocular, simply divide the aperture of your objective lens by the magnification of the binocular. So, for example, an 8×20 pocket binocular will have an exit pupil size of 20 divided by 8 or 2.5  mm. A larger 10×50 binocular will have an exit pupil twice the size at 5 mm. Why is the maximum set at 7 mm? Well, the pupil of the human eye maxes out at 7 mm for most people, when the eyes are fully adapted to darkness. Thus, having a binocular with an exit pupil larger than 7 mm will result in wasted light, as not all the light collected by the objectives gets directed into the eye.

The exit pupil is the circular shaft of light seen when a binocular is held up to the light

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1  Binoculars 101

The upper maximum of 7 mm is true for most young people. It is widely believed that as one ages the maximum size of the exit pupil decreases. While this is generally true, there are many examples of older people having very large exit pupils and some now consider this decrease in exit pupil size with age to be a bit of an urban myth. I think it’s safe to say that while there is a decrease in exit pupil size with age, the shrinking is far less drastic than previously believed. And while many sources claim that by age 60 or 70, the dilated pupil shrinks to 5 mm, it may not be true for the majority of people. Large exit pupil binoculars have clear advantages in low light conditions or while observing faint objects in the night sky. But during daylight applications, smaller exit pupils can be used profitably. Indeed, during bright sunny days, the human exit pupil shrinks to just 2 or 3  mm. Are there other advantages to using larger exit pupils? Yes! For one thing, many observers find it easier to center their eyes in the eyepieces, reducing the incidence of blackouts and improving the comfort and immersivity of the views. Conversely, small exit pupils make it more difficult to comfortably center one’s eyes to such a degree that some observers cannot get on with binoculars with exit pupils less than 4 mm. That said, smaller exit pupils may help bespectacled folk who normally wear glasses to use their binoculars without them. The reason for this is that smaller exit pupils expose far less of the aberrations found in the outer part of the eye lens and so, effectively, they will be using the best part of their eye lens to view the scene. In addition, this author enjoys exit pupils less than 5 mm when viewing astronomical targets as it darkens the sky better than using instruments with larger exit pupils. Star images appear slightly more pinpointed and crisper at those smaller exit pupils too.

Eye Relief The eye relief of a binocular, usually quoted in millimeters, is the distance from the eyepiece that your eye needs to be placed in order for all the light from the eyepiece to fall onto your retina when the exit pupil is the same size as the size of the pupil of your eye. It’s measured from the back surface of the eye lens.

Schematic of the eye looking through a binocular eyepiece. The number 3 indicates the relief of the eyepiece. (Image Credit: Wiki Commons)

Collimation Considerations

9

In the past, binocular eyepieces had very poor eye relief making it difficult for the bespectacled among us to access the entire field. But over the last few decades, optical designers have put much more effort into creating eyepieces with more generous eye relief so that even if you happen to observe with proverbial ‘milk bottle’ glasses, you can now enjoy the full field of view. In the past, older eye piece designs were fitted with soft rubber eyecups that could be folded down to allow the user to use his/her spectacles to image the field. Modern binoculars usually have more advanced twist-up eyecups offering a number of positions that can enable the user to get the best views from their binoculars. In general, about 15  mm is usually quoted as the minimum eye glass wearers require to successfully access the entire field, though in practice many manufacturers advertise overly optimistic figures with the result that the quoted eye relief for a given model is often not what they experience in practice. But is more and more eye relief a good thing? No, not at all. You see, as eye relief increases it becomes increasingly more challenging to position one’s eyes precisely behind the eyepiece which can exacerbate blackouts while viewing though the instrument. In practice, rarely will anyone require more than 20 mm of eye relief.

Interpupillary Distance (IPD) Humans have widely variable distances between their eyes. Some are very wide-­ spaced, while others have very closely-spaced eyes. The distance between your eye pupils is called the Inter-Pupillary Distance (IPD) usually measured in millimeters. Smaller individuals, like children and women usually have smaller IPDs anywhere between 50 and 60 mm. Men usually have larger IPDs anywhere from 60 to 75 mm. Binoculars vary quite a bit in their IPD range, and this is an important consideration when finding binoculars that best fit your face. Many children, for example, cannot use large and medium sized binoculars because the eyepieces cannot be spaced close enough for them to merge the images properly. Thus, it’s always good to check the IPD range of your binocular prior to purchasing. Better still, and if possible, try the binocular before you buy!

Collimation Considerations In order to derive the best possible images out of your binocular, the optical elements must be aligned in each barrel but also must be aligned in such a way that the images can be merged into a single stable viewing field, when the eye-brain system can perceive depth. Not only must the barrels be aligned to each other but also to the hinge or other axis about which your IPD is adjusted. Furthermore, the optical axes must be aligned both in the vertical and the horizontal directions. Moreover, accuracy of collimation scales directly with magnification. A binocular magnifying 16×

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1  Binoculars 101

has a collimation tolerance only half that of an 8× instrument. This becomes particularly important in high power binoculars used for terrestrial distance viewing and astronomy, where achieving collimation can be far more challenging and indeed limits the highest powers that can be profitably employed.

Magnification Considerations You’ve probably noticed that most compact binoculars come in magnifications anywhere from 6× to 12×, while the most common powers are 8× or 10×. Most novices make the mistake of thinking higher power binoculars will be better. They reason that higher magnifications will give a more enlarged image, with more details popping into view. While this is broadly true, they fail to consider the difficulties of hand-holding a binocular delivering powers of 10× or 12×. While the weight of the binoculars may not be substantially different, holding a 12× glass steady is much more challenging than using a 10× glass, and an 8× instrument will be easier again to hold steady. Image steadiness is very important in order to glean as much detail as possible from the binocular image, and how steady you can hold the binocular in your hands will dictate your preferred magnification choices. Magnification will also dictate to some degree the brightness of the images your binocular will deliver, especially when the light fades in the evening or while glassing at dawn. For example, a 7×42, which delivers a 6 mm exit pupil will serve up a noticeably brighter image than a 10×42 – all other things being equal – under low light conditions. For astronomical applications, larger aperture binoculars offering much high powers are quite common. The author owns and uses a 20×60 mm Pentax Porro prism binocular that he uses for observing the Moon and the brighter deep sky objects. But if you think such an instrument can be hand-held, think again! Without a tripod, this high-power binocular will magnify the shakes in your hands and make observing fine details hopelessly impossible.

Aperture Considerations Binoculars come in a huge range of objective diameters, anything from 20 mm right up to 150 mm or more. For daylight applications, when the light is good and strong, smaller apertures between 20 mm and 42 mm will serve you well for most purposes. Take for example, a small pocket binocular with specification 8×20. Because the human eye pupil shrinks in size in broad daylight down to 2 or 3 millimeters, the small exit pupil of 2.5 mm on the 8×20 lets through plenty of light to give very satisfying views of the landscape. Indeed, many observers report no gain in image brightness comparing binoculars with various size exit pupils when the ambient light is good. The advantages of larger apertures come into their own during dull overcast days or when glassing under a heavily shaded forest, as well as at dusk and dawn when

Glass Types

11

the intensity of sunlight is minimized. During these times, it’s best to switch to a larger aperture binocular possessing a larger exit pupil, so you can take maximum advantage of those low-light conditions. Another advantage of larger apertures is that they can resolve finer details, though it may not be obvious in hand-held field use. For most birding or general nature observations, smaller binoculars with apertures less than 42 mm will probably meet all of your requirements. Having used many different binocular apertures over the years, this author has come round to thinking that apertures of 30–35 mm are probably ideal. Using magnifications of 7× or 8× these apertures will transmit enough light to your eyes to sate all your demands during the day but will show their limitations as the light levels drop off at dusk or dawn. Other birders prefer to use 42  mm instruments perhaps because their exit pupils are larger making it easier to get the eye box squared up with your eyes. But that comes with an increase in carrying weight. In general, the larger the binocular you use, the heavier it becomes. That may not present as a problem if the instrument is used only casually or for short excursions, but in my experience, carrying around a 42  mm aperture binocular over many miles for a few hours every day quickly induces neck strain. That’s where the considerably lighter weight of the 30–35 mm binocular class really comes into its own as these tend to be about 50% lighter than the equivalent 42 mm instrument, all other things being equal. Hunters often prefer larger, low-light binoculars in apertures of 50 mm or 56 mm and employing magnifications anywhere between 7× and 10×. These will greatly extend the time one can engage with their targets as the light fades in the evening or at dawn. And as one might expect, these large aperture binoculars are an excellent choice for stargazing, as they collect more light than smaller aperture instruments.

Glass Types For the vast majority of the history of the binocular, the lenses making them up were composed of two types of glass, called crown and flint. By combining these two types of glass, much better color correction could be achieved. Indeed, until the end of the nineteenth century, such telescopes were the best in the world. When the magnification is increased however, high contrast objects will show a blue or purplish fringe around the edges of objects which opticians refer to as chromatic aberration. This is caused by the slightly different angles by which the different colors of white light emerge from the objective after being focused by the objective. Fortunately, because most common binoculars used by birders and naturalists employ low powers (mostly less than 10×), chromatic aberration is not much of an issue, but folk vary in their ability to detect it. Some people are just more sensitive to chromatic aberration than others. In general, the higher the magnification, the greater the chromatic aberration seen. In recent years, traditional crown & flint binocular objectives have been replaced with so-called extra low dispersion (ED) glass. In ED objectives, the crown element

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is mated with a type of flint made from exotic materials such as calcium fluorite or some synthetic version of calcium fluorite. The resulting doublet focuses the individual colors of light more tightly than traditional crown and flint objectives, resulting in a slightly sharper image with greater contrast. When used alone, low dispersion glass can cause its own type of color fringing, which is why it is often paired with ordinary optical glass to achieve the best possible optical performance. The Abbe number is a measure of the amount of dispersion or chromatic aberration that occurs when light passes through a material. Dispersion refers to the phenomenon where different wavelengths of light bend or refract by different amounts when they pass through a material, resulting in color fringing or blurring of images. The Abbe number is defined as the ratio of the difference in refractive index between two specific wavelengths (usually the spectral blue F line at 486.1 nm and the red C line at 656.3 nm) to the refractive index at the yellow sodium D line at 589.3 nm. A material with a higher Abbe number has a smaller difference in refractive index between the blue and red wavelengths, indicating lower dispersion. In optical systems, chromatic aberration caused by dispersion can be corrected by combining lenses made from different materials with different dispersion properties. A lens made from a material with a high Abbe number (lower dispersion) can be paired with a lens made from a material with a low Abbe number (higher dispersion) to reduce chromatic aberration. Therefore, the Abbe number is an important factor to consider when selecting optical materials for lenses, prisms, and other optical components. A material with a high Abbe number is desirable for applications that require minimal chromatic aberration, such as high-quality camera lenses, telescopes and binoculars. Conversely, a material with a low Abbe number may be more suitable for applications where dispersion is intentionally used, such as in diffraction gratings and dispersion prisms. By combining low dispersion glass with ordinary optical glass, lens manufacturers can create a lens that has a more balanced refractive index across the visible spectrum of light, leading to better color correction and reduced color fringing. This is known as an apochromatic lens, or APO lens. In short, the combination of low dispersion glass with ordinary optical glass is done to create a lens that can achieve the best possible optical performance with minimal color fringing. While ED glass has been used very successfully in refracting telescopes- see my book, Choosing & Using a Refracting Telescope – which use high magnifications more or less routinely, their benefits in low power binoculars is not nearly so dramatic. Yes, when properly executed, ED binoculars will present a slightly crisper, more contrasted image, but the effects are often quite subtle. In this author’s experience, ED glass is not something he would insist on when making a prospective purchase of a new binocular for birdwatching, as he has seen many models with traditional crown & flint objectives give better results than those sporting poorly executed ED glass objectives. What’s more, not all ED glass is of equal quality. Some ED glass shows barely perceptible results, while higher quality ED glass binoculars show noticeably improved images.

Glass Types

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There are many types of ED glass available today. For example, FPL51, FPL53, and fluorite are all types of optical glass that are commonly used in high-quality lenses and optical systems. Here are the key differences between these three materials: FPL51: This is a type of ED (Extra-low Dispersion) glass produced by Ohara Corporation. It has a relatively high Abbe number of around 81, which means that it has lower dispersion than standard optical glass. FPL51 is used in many high-­quality lenses and optical systems and is known for its ability to reduce chromatic aberration. FPL53: This is another type of ED glass produced by Ohara Corporation. It has a higher Abbe number than FPL51, at around 95, which means that it has even lower dispersion. FPL53 is often used in lenses and optical systems where the highest level of color correction is required. Fluorite: Fluorite is a naturally occurring mineral that has very low dispersion and is highly transparent to visible light. It is sometimes used in lenses and optical systems where the highest level of color correction and image quality is required. However, fluorite is relatively rare and expensive, and can be difficult to manufacture into optical components. In general, FPL51 and FPL53 are synthetic glasses that are more readily available and less expensive than fluorite. FPL53 has a higher Abbe number than FPL51, which means that it has even lower dispersion and is better at correcting chromatic aberration. However, both FPL51 and FPL53 can have higher levels of dispersion than fluorite, which can limit their performance in certain applications. Fluorite, on the other hand, has the lowest dispersion of the three materials and is therefore often used in applications where the highest level of color correction is required. In more recent years, other designations have appeared including HD or UHD or some such. HD presumably stands for ‘high definition,’ (or ultra-high definition in the case of UHD) but it’s often unclear to the consumer what this entails. Better coatings and better figured glass elements might bring about a boost in contrast making the images appear more sharp or more highly contrasted, but these instruments may not, in fact, possess ED glass elements. Often these monikers are merely marketing hype more than anything else, so buyer beware! One myth promulgated by some binocular reviewers is that the presence of ED glass boosts image brightness. That is not the case, or rather, not strongly attributed to the finer focusing of the various wavelengths of visible light. ED glass can improve image quality by reducing chromatic aberration, it does not necessarily make the images appear brighter. Brightness in binoculars is primarily determined by the size of the objective lens and the quality of the coatings on the lens surfaces. A larger objective lens allows more light to enter the binoculars, which can result in a brighter image. Coatings on the lens surfaces can help to reduce glare and improve light transmission, further enhancing perceived image brightness. By itself, the slightly tighter focusing of the individual wavelengths will increase image brightness by a tiny fraction of 1%. So where does the claim that ED glass deliver brighter images come from? Most sources of misinformation usually has a grain of truth to it. I believe this might have arisen by considering how much light

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is reflected off light of different refractive indices. It was after studying some of the work of Augustin-Jean Fresnel (1788–1827) that I got a lead. His equations provided important advances in computing how much light is transmitted and reflected with materials possessing different refractive indices. Many of the Fresnel equations are quite complex, as they involve light incident upon a surface at different angles. Let’s look at one particular equation:

 

 cos x  n 2  sin 2 x R  cos x  n 2  sin 2 x 

 

  1/ 2  

1/ 2



2



Where R = the amount of reflected light from an optical surface x = the angle of incidence and n = the refractive index of the material. We can simplify this greatly by considering light arriving directly along the normal (i.e. looking at the center of the lens head-on, so x = 0), from which we obtain the much simpler equation: 2



1  n  R  1  n 

So the amount of reflected light only depends on the refractive index of the optical glass used. Now consider regular crown and flint glass having a refractive index of about 1.5. The amount of light reflected off such glass for normal incidence is: 2



 1  1.5  R   0.04 1  1.5 

Note: This is the origin of the 4% figure often quoted in telescope optics texts for uncoated glass. Next consider extra low dispersion (ED) glass like fluorite or FPL 53 or some such, with a refractive index of 1.44. Plugging this number for n into the Fresnel equation delivers a value of 0.03 or 3%. This means that regular crown or flint glass transmits 96% of the light incident upon it compared with 97% for ED glass. This is a very small difference but considering that only one or two elements in the optical train employ ED glass, and the applications of multiple layers of antireflection coatings further reduce the light losses for both types of glass, the visual difference in brightness will be all but indistinguishable. So there you have it! Although the Fresnel equation allows for a 1% difference in transmission, it amounts to effectively negligible differences in overall transmission, all other things being equal. Don’t believe the hype!

Binocular Eyepiece Designs

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While ED glass does not directly affect image brightness, it can help to improve contrast and color accuracy, which can make images appear more vivid and detailed. So, while ED glass is not a direct factor in image brightness, it can contribute to overall image quality and clarity. In sum, never purchase binoculars solely based on whether they have ED glass or not. There are many more important features that need to be executed well before you’ll even begin to see the benefits of having it. Indeed, some of the best binocular optics don’t contain any ED glass elements, so something to think about. What will boost image brightness in dim light however, is greater transmission of blue light, as the eye becomes more sensitive  to shorter wavelengths as the light fades.

Binocular Eyepiece Designs Most binoculars sold on the market today consist of three or more lenses arranged in two or more groups. By far the most common is the venerable Kellner eyepiece dating all the way back to 1849, which consists of a single field lens and doublet eye lens. Another common design is the reverse Kellner, a design that was introduced in 1975 by David Rank of the Edmund Company, where the doublet becomes the field lens and the eye lens is a singlet, which presents a slightly wider field of view than the original Kellner design (50 degrees vs 45 degrees) and much better eye relief.

Schematic of the Kellner eyepiece design. (Image Credit: Wikipedia)

Wide angle binoculars usually employ a more advanced Erfle or modified Erfle, having five or six elements in three groups to better correct off axis aberrations. These Erfle designs had their first prototypes in 1917, after which they first hit the market in the early 1920s were first used in the Zeiss Deltrentis 8×30, as well as the Delactis and Delturis 8×40 models.

The 5 Element Erfle design. (Image Credit: Wikipedia)

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Diopter Adjustment Very few people have identical eyes. The quality of the image in one eye may be noticeably superior to the other, or there may only be small subtle differences between them. Because binoculars employ both of your eyes, some provision is usually necessary to adjust the focus on one eye independently of the other. This is where the diopter compensation adjustment comes into play. Most lower cost binoculars have a ring located under the right eyepiece, usually set to zero when it comes out of the box, but with+or – scales. Most binoculars offer a range of+/− 4 or 5. Diopter adjustment is one of the first things you will need to do in order to get your binocular working correctly. First cover the right objective and look through the binocular. Only the left-hand barrel will be showing its image. Focus the image on a target in the middle distance, at least 40 meters away. A signpost with some lettering or numbering on it is ideal. Using the central focusing wheel, bring the image to sharp focus, so that you can clearly make out the letters or numbers. Next, cover the left objective and once again look through the binocular at the same target. This time don’t touch the central focusing wheel but instead move the diopter ring either clockwise or anti-clockwise until you get the image as sharp as you possibly can in your right eye. Once you’ve done this, your binoculars are good to go. Just use the central focusing wheel from now on to get the crispest views your binoculars are capable of. Many top-rated binoculars have more sophisticated diopter compensation mechanisms usually involving a lockable diopter adjustment. Probably the most frequently encountered designs involve pulling the central focusing wheel out, which exposes a diopter scale. This is adjusted by rotating the focuser while undergoing the same procedure outlined above. Once your desired setting is achieved, the focus wheel is pushed down again, locking your desired setting into place. Locking diopters have the obvious advantage of maintaining your preferred diopter setting. In contrast, the non-locking types tend to move in field use necessitating re-adjustment every now and then. Of course, if you share your binoculars with others, a non-­ locking diopter may turn out to be a better choice, as each observer will likely require a different diopter setting.

Depth of Field If you use a variety of binoculars, chances are you’ll notice that some instruments keep targets sharply in focus over a large range of distances. The wider this range within which sharp focus can be maintained is known as depth of field. It can be shown with a bit of optical theory that magnification is the key factor determining how much depth of field your binocular will deliver. In general, the lower the magnification, the greater the field depth. More technically, the depth of field scales inversely with the square of magnification. So, if one were to compare two

Field of View

17

binoculars of the same type, say 6× and 12×, the 12× glass will have a depth of field four times smaller than the 6× glass. Depth of field is a very important consideration, especially during daylight applications. Birders, for example, find it highly desirable to use binoculars with large depths of field in order to follow their avian targets which may suddenly flit from one tree to another. Having a binocular with a large field depth means that less vigorous focusing (or none at all) is required and that means you can spend more time enjoying and studying your subject. Field depth is far less important when using binoculars to view astronomical targets since all these objects are located at infinity, or nearly so. That’s especially fortunate, as most specialist binoculars used for astronomical viewing employ high magnifications. Before leaving the subject of field depth, the above discussion did not consider near depth perception, that is, how sharp the image appears in the foreground within the closest focus distance at infinity. Field curvature can have a major impact on this and can enhance the sense of field depth of objects in the near ground. It is this near-depth perception that will probably vary most among individuals, with younger eyes experiencing the most dramatic effects owing to their enjoying greater focus accommodation. People who have strong myopia (shortsightedness) may need greater ‘beyond infinity’ focus to reach a satisfactory focus with a given binocular. That’s because a normal individual’s position of infinity focus will not be quite enough to allow a strongly near-sighted person to achieve an adequate focus of a distant object. It’s advised that such individuals always check that an object located at distance- say half a mile or more away – can be sharply focused. Furthermore, when the pupil of such an individual dilates at night, the depth of focus of his/her eyes will decrease further – requiring even more ‘beyond infinity’ focus to observe comfortably. For more on depth of field and depth perception, I would refer you to Holger Merlitz’s Binocular Handbook.

Field of View Another important binocular consideration is the field of view available for observing objects. There are various ways in which the size of the field of view can be expressed. Perhaps the most common is to use feet at 1000 yards. For example, if your binocular provides a field of view of 350 feet at 1000 yards, this means that you can view objects 350 feet across when viewed at a distance of 1000 yards. In Europe, meters at 1000 m is more commonly employed. Astronomers prefer an alternative expression for the field of view. They use angular degrees. To convert feet at 1000 yards to angular degrees divide by 52.4. So, a binocular offering a field of view of 342 feet at 1000 yards will have an angular field of view of 342/52.4 = 6.53 degrees. Put another way for my European readers, each degree of view is equal to 17.5 m at 1000 m. When surveying the specifications of a binocular, you’ll often come across the terms, Apparent Field of View (AFOV) or Apparent Angle of View (AAOV). These both refer to the same thing: the angle

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of the magnified field when you look through the optics. This figure is approximated by multiplying the actual field of view by the binocular’s magnification. Binoculars with AFOV greater than 65° are considered “wide angle.” In general, the lower the magnification a binocular provides, the wider the field of view available. The size of the field has absolutely nothing to do with the size of the objectives used but has much more to do with the types of eyepieces employed in the design of the instrument. Over the last few decades designers have steadily increased the fields of view available, so today it’s not uncommon for a typical 8×42 binocular to provide a field of view of 8 degrees or more. Throughout the golden age of the Porro prism binocular between the 1960s and 1980s Porro prism binoculars usually had much wider fields at the same magnification than the equivalent roof prism model, but in recent years the latter design has caught up, where it now offers fields of the same size or larger than current Porro prism designs. Wide fields of view have many obvious advantages, the most important of which is the swathe of terrain that can be examined at a glance. Birders typically go for binoculars with wide fields of view because their subjects – fast moving birds – can suddenly take to flight, flitting from tree to tree. Having a wider field will allow the birder to keep the subject inside the field of view as it moves around. Wide fields are also good for scanning large areas quickly. On the other hand, higher magnification fields of view are more restricted but are often better for spotting objects at a distance. Some folk get too distracted using overly large fields and prefer to ‘frame’ their subjects better in a smaller field with less distractions. In the end, there is a strong personal dimension to the size of the field of view one can enjoy. And while some claim that once you go to super wide fields of view, there is no turning back, this author enjoys binoculars with fields that vary in width from 2.2 degrees right up to 9.5 degrees!

Porro Prism Binoculars Let’s now take a closer look at arguably the most familiar type of binocular recognized by the general public; the time-honored Porro prism binocular. Prior to 1960, these were practically the only type of binocular used by outdoor enthusiasts and stargazers alike. And while the roof prism models have made great strides over the decades, Porro prims binoculars are still excellent choices for modern observers. Porro prism binoculars are much cheaper to make well compared with a roof prism model of equivalent quality. Porro prisms are of a much simpler geometrical shape than roof prisms and transmit between 12% and 15% more light through the binocular compared with entry-level roof prisms. That’s because the path the light takes through the Z-shaped Porro prism system is far less complex than in a roof prism instrument. For one thing, the light moving through Porro prisms undergoes 4 reflections, whilst the roof binocular requires five such reflections. This also contributes to the Porro prism binocular delivering brighter images. By design, a roof prism requires one surface to be coated with a reflective material like aluminum, silver or modern dielectric coatings in order to reflect light through the binocular. As

Porro Prism Binoculars

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the light strikes this surface, some of it is inevitably lost resulting in a dimmer image. Porro prisms need no such reflective surface. To complicate things a little, there are actually two types of Porro prism designs: I and II. Porro I systems use a simple symmetrical prism arrangement, where the two prisms are placed in parallel and face each other. The light enters the first prism, reflects off the surface at 90 degrees, and passes through the second prism before reaching the eyepiece. These are found in the vast majority of commercial Porro prism binoculars. Porro II designs are similar to Porro I except that the second prism is cut in half which are subsequently glued onto the first prism. Optically both Porro I and II systems are very similar. They have the same number of refections, the same glass path, using the same size prisms. The main differences between them is that the Porro II system has a smaller axis offset and are slightly harder to make. The advantage of the Porro II design lies with its shorter size of beam direction and so is advantageous to models in which the IPD has to be set on the eyepiece side of the instrument. Porro II systems are routinely used in Canon Image Stabilized (IS) binoculars and large astronomy binoculars, as well as having various applications in the military.

Porro I Optical system most commonly used in commercial binoculars. (Image Credit: Wikipedia)

BaK4 prisms are considered the best type of Porro prism, as they are made of superior optical glass to produce clearer images. The reason this is the case is because BaK4 prisms have a higher refractive index than BK7. As we saw earlier, the refractive index of a material is a measure of how much the material can bend or refract light. When light passes through a material with a higher refractive index, it bends more than when it passes through a material with a lower refractive index. In binoculars, prisms with a higher refractive index bend the light more than prisms with a lower refractive index. This bending of light helps to correct the image and minimize the aberrations, which makes the image appear clearer and sharper. The amount of light transmitted through the prism also depends on its surface area and the angle at which the light strikes it. Therefore, prisms with higher refractive index values transmit more light in binoculars because they can bend the light more, leading to clearer and brighter images. However, higher refractive index materials can also be more expensive, so binocular manufacturers need to balance the cost and performance when selecting prism materials.

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More technically, the critical angle- the angle of incidence above which total internal reflection occurs inside a prism – scales as Arcsine (1/n), where n is the refractive index of the glass, it follows that prisms which possess a higher refractive index can reflect a greater range of incidence angles than one with a lower refractive incidence and that results in more light reaching your eyes. In addition, because BaK4 glass can accommodate a greater range of incidence angles, it can tolerate steeper light cones than BK7 systems and thus can be used in shorter focal length optics to help keep the binoculars as small and portable as possible. BK-7 prisms are used, for the most part, in lower priced binoculars serving up smaller fields of view. These are satisfactory, but inferior to the BaK-4 prisms. Binoculars with BK-7 prisms can often (but not always) be revealed by a squared-off side to the general roundness of the image. BaK-4 prisms show a truer round exit pupil, which translates to better light transmission and edge-to-edge sharpness and so deliver a naturally brighter image. All that being said, the reader may be interested to know that not all BaK4 glass is created equal. The original BaK4 glass developed by Schott has a refractive index of 1.5688, but Chinese BaK4 (found in most binoculars derived from China) has a slightly lower refractive index of 1.5525, so the critical angle will be higher than Schott BaK4 (39.6 vs 40.1 degrees). This means that the Chinese BaK4 glass will reflect a smaller range of wavelengths compared with its Schott equivalent. However, the Chinese BaK4 has a higher Abbe number than Schott BaK4 which results in lower dispersion which can improve color correction. On the other hand, Chinese BaK4 has a higher bubble count than Schott BaK4, which means that light travelling through the material has the greater potential to be scattered. However, you’re unlikely to see any differences between these two glasses in actual use. Moreover, Chinese BaK4 shouldn’t really be classified as BaK4 since the original Schott glass contained Barium (chemical symbol Ba) crown glass, whereas the Chinese equivalent is a phosphate crown that happens to have a refractive index much closer to Schott BaK4 than Schott BK7. The design tolerances of Porro prism binoculars are also much higher than their roof prism counterparts. For example, the Porro prims need to be aligned to an accuracy of 10 arc minutes – 300 times higher than roof prisms. This fact alone makes Porro prism binoculars much easier to mass produce. Careful observers have noted a more enhanced 3D (image plasticity) effect using Porro prism binoculars. Is there a basis for this effect in reality? Yes, indeed there is. To see how, read on. Suppose we are looking at two objects along the same line of sight; one located at a distance of 10 m say, and another located at 15 m, as illustrated in the figure below, only with greatly exaggerated angles for the sake of clarity.

Porro Prism Binoculars

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Modelling Stereopsis

For a roof prism binocular, assume that the distance between the centers of the objectives is the same as the inter-pupillary distance which is ~6.5 cm (0.065 m) for my eyes, so half this length, 0.0325 m, represents x in the diagram above. Using simple trigonometry, at 10 m distance the half angle B subtended by the object in the roof prism binocular is given by Arctan (0.0325/10) = 0.186 degrees or 11.2 arc minutes (designated by 11.2′) Similarly, the object located at 15 m will subtend a half angle A given by Arctan (0.0325/15) = 0.124 degrees or 7.4′ Therefore, the image plasticity is provided by the angular separation B-A = 3.8′ Next consider the same scenario for a Porro prism binocular, just like my Nikon E II, with a spacing between the objective centers measured at ~12.5  cm, so x increases to 0.0625 m At 10 m distance angle B is given by Arctan (0.0625/10) = 0.36 degrees or 21.5′ and angle A is given by Arctan (0.0625/15) = 0.24 degrees or 14.3′ Therefore, the angular separation (Image plasticity), B-A, for the Porro prism binocular is 21.5–14.3 = 7.2′ Thus, without considering magnification, the Porro will show a much more discernible spatial difference between the objects than an equivalent roof prism model. Notes:  The more widely set one’s eyes are the greater the 3D effect manifested. So those who enjoy a wider IPD will experience this better, all other things being equal. The wider the separation of the objectives in the Porro prism binocular, the greater the 3D effect. The reader will also note that as the distance to both objects is increased, the differences between the roof prism binocular and the Porro will

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diminish. For example, similar calculations show that the same objects located at 60 and 65 m, respectively, would have an angular separation of only 0.15′ in the roof prism binocular and 0.3′ in the Porro prism counterpart. Since the limit of resolution of the human eye is about 1 arc minute, the differences here will be all but indistinguishable. So, we can conclude that the 3D effects of Porro prism binoculars work optimally at middle distances, and all but vanish at larger distances. The above discussion did not consider the role of magnification though. The key point here is that the binocular will magnify those small angular differences and so help the eyes to spatially distinguish the objects better. So, for example, two objects at a distance of 190 m and 200 m will subtend an angular separation of 9.1′ and 8.6′, respectively in an 8× glass. The difference is about 0.5′, which is just on the cusp of discernibility under ideal conditions. The same result at 10× gives 0.6′; only a trifle better. So we may conclude that this 3D phenomenon all but vanishes. In summary, the 3D view is most pronounced when the separation between the objectives is as large as possible, and when the magnification used is higher. Can you see these effects? Absolutely! Just compare looking at a long stretch of road with a roof prism and Porro prism binocular of the same specification. You’ll be able to discern the undulations on that stretch of road far more acutely than with the roof prism instrument. Those who enjoy architectural features of buildings will greatly appreciate the enhanced stereoscopic images generated by Porros too. It just adds another level of dimensionality to the binocular image that I especially enjoy. It’s important to note that not all binoculars using Porro prism designs provide an enhanced 3-D effect. So-called reverse Porros designs have the eyepieces further apart than the objectives – the exact opposite of that found in a conventional Porro prism binocular – making the images very flat as a result. Let’s now discuss some of the downsides to using Porro prism binoculars. Though the Porro prisms are much more forgiving to collimation errors than roofs, their components are generally not held together as tightly, with the result that they are more prone to going out of alignment than a high-quality roof prism model. But if you handle them with care, they should deliver a lifetime of good views. Porro prism binoculars do not generally have great close focus. Typically (but not always) it can be anywhere from 2.5 m to as much as 5 or 6 m. This will come as a disappointment to those who enjoy studying insects and flowers at close range. Moreover, Porro models are much more challenging to use on objects located less than about 5 meters away as one has to adjust the IPD to merge the images adequately. Roof prism models are far more comfortable to use when viewing objects located close at hand (90%) light transmission, can fulfill many of the functions of larger 42  mm formats, especially if all your glassing is carried out in broad daylight. In addition to their larger objective diameters, compact formats are often easier to hold steady in one’s hands compared with pocket models. That’s precisely the conclusions this author has reached after testing many pocket and compact binoculars in the field. Indeed the 8×30/32 is the format he most uses for serious binocular excursions. Let’s now explore a variety of popular models available on the market, staring with the more economical instruments followed by some detailed discussions on the very finest instruments available in this very popular format.

83 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_4

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Bargain Basement Compact Porro Prism Binoculars Though I’ve been investigating the binocular market for several years now, I’ve had more of my fair share of fun with a number of Opticron-branded binoculars. Opticron began trading back in 1970 here in the UK, founded by a family passionate about bringing good value instruments to a rapidly expanding sports optics market. Today, Opticron enjoys a substantial part of the global market for binoculars, spotting scopes and a host of other optical technologies, and has gained the trust of many thousands of enthusiasts on every continent on earth. Like the majority of companies in this industry, production of Opticron products has moved mostly to the Far East, either in China or Japan, where their well-orchestrated production lines continue to manufacture high quality optical products to sate the demands of customers from every economic bracket. Today, their optical wares are well respected as offering exceptional value for money and backed up by some of the best warranties in the industry. As you may have gathered, I’ve spent most of my time testing modern roof prism designs, which are understandably very popular with nature enthusiasts, birders and hunters alike. The advantages of roof prism models include their compact, sleek design, internal focusing and ease with which they can be rendered weather resistant. But for all their charms, roof prisms are much more difficult to make well compared with the older, more traditional, Porro-prism designs. For one thing, they need specialized phase correction coatings that bring the electric field vectors into precise alignment after being shifted out of phase, travelling through the roof prism. They also require aluminized, silvered or dielectric coatings to boost the light transmission to the eye to achieve their high-contrast images, before they can begin to compete with their Porro-prism counterparts. But while the market has clearly moved in favor of roof prism designs, it’s good to see that some of the leading binocular manufacturing companies have retained one or more Porro-prism models that offer wonderful optical performance in classic configurations. I speak of course of the Swarovski Habicht, for example, which is still available in 30 mm and 42 mm formats, and offer exceptional optical performance at prices substantially below their equivalent roof prism counterparts. Zeiss also continued their manufacturing of classic Porro-prism designs, like the multicoated Jenoptem 8×30, well into the 1990s, and the later models still provide fine optical performance. Nikon also makes its highly-lauded EII as a premium product, as well as a number of less expensive porro-prism models – the Aculons & Actions come to mind- that deliver decent optical performance for their modest price tags. But it’s also nice to see other binocular companies like Opticron, Vortex, Kowa, Olympus, Canon and Leupold continue to offer small Porro-prism binoculars at very economical prices. Truth be told, with vast improvements in optical glass quality, modern multi-­ coating technology, and advancements in materials science, it’s possible to produce an optically excellent Porro-prism binocular for a very modest financial outlay. The first binocular I wish to showcase in this chapter is the Opticron Adventurer 8×32 T WP.

The Opticron Adventurer T WP 8×32

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The Opticron Adventurer T WP 8×32

The Opticron Adventurer T 8×32 WP is a well-built binocular, with solid mechanics

My attention to the Opticron Adventurer T WP 8×32 was piqued after reading some reviews made by British binocular astronomer, Stephen Tonkin, who showcased a very interesting Adventurer T WP 10×50 model, and highly recommended this model as a well-built and optically excellent stargazing binocular available for under £100. Indeed, this was also reflected in the many favorable reviews left by stargazers about the same model. But there was almost nothing mentioned about the smaller models from the same line; namely the 42 mm and 32 mm models. I discovered that 32 mm Adventure T WP had a nice, light weight- 540 g – quite typical even for a roof prism model of the same aperture class. It offered a good, wide field of view too −8.2 degrees to be exact – again right up there with some of the widest fields available in the top-selling roof prism brands. But unlike many older models, which offered just coated or multi-coated optics, these porro-prism binos from Opticron were fully mutli-coated, ensuring a high light transmission – at least in theory. Holding it in my hands, I was very satisfied with its sturdy build. The central hinge is good and stiff, easily maintaining my preferred inter-pupillary distance. The focus wheel is very nicely engineered, rotating smoothly with a fair amount of tension and without any play or backlash. The eye cups are the old-school rubber design, but they felt quite comfortable to rest my eyes on. When folded down, the instrument can be used with eyeglasses, but you’ll have to move your eyeball around to see it all, so a fairly tight squeeze! Diopter compensation is achieved by rotating

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a ring located under the right ocular. It also moves smoothly but I would have liked to see that little bit more tension. I hit my one and only snag as I began to remove the nicely designed objective covers from the barrels. The rubberized armoring immediately covering the left ocular came away, as I struggled to tease the objective cover off. Fortunately, I had some Gorilla glue handy, and simply applied a bit to the inside of the armoring before putting it back on. It worked a treat, but it did leave a few glue streaks around the rim. The objectives are quite deeply recessed, with the anti-reflection coatings almost disappearing in normal daylight. That’s a good design feature, as it affords greater protection from dust, rain and stray light. I was delighted to see that Opticron made a provision for affixing the binocular to a tripod. Good move! The binocular handles very well indeed. It’s super easy to grip and wrap one’s fingers around. The focus wheel is easily accessed and moves with a very reassuring amount of tension. Fit and feel are way better than I expected, given its rock-­bottom price. But how did the optics hold up? I had read that more economically priced porro-prism binos, like this 8×32, often have stopped down apertures. This was very easy to test however, simply by directing my Iphone torch through the ocular lens and observing the size of the circle of light projected through the objectives onto a flat surface. The results were very encouraging: the effective diameter was 31 mm, quite in keeping with the 32 mm advertised aperture. Aiming at a bright light, I was pleased to see internal reflections were kept well under control with no annoying diffraction spikes, but examining the exit pupils did reveal some light leaks outside the pupils which have the potential to throw up some glare in low light situations when the exit pupil dilates. The Opticron Adventurer 8×32 T WP delivers a very good image in daylight tests. The sweet spot is generously large. Contrast and color rendering were both excellent. Images snap to precise focus, with the focus wheel moving through about one and a half full rotations from nearest focus (measured at 3.24 m) to infinity. What immediately impressed me most was the instrument’s wonderful, immersive three-dimensionality. This amazing effect is far more acutely perceived in this binocular than in any roof prism instrument I’ve had the privilege of using. Of course, Porro-prism binoculars are known for this, but it still came as quite a surprise to me when scanning a stretch of river, an open field, or a woody glade. The viewing is extremely comfortable too. I encountered no blackouts or rolling ball effects while panning large swathes of wooded terrain. The binocular does suffer a little bit from glare (including veiling glare), especially when it’s pointed near the Sun, but no more than many other binoculars I’ve tested costing many times more. In most situations, this glare can be minimized simply by outstretching one’s hand. When the light fades however, I did begin to detect additional glare in certain situations as my eye pupils began to expand and interact with the aforementioned ‘false pupils.’ I noted very little chromatic effects within the sweet spot but did begin to see traces as my eyes were directed towards the edges of the field. The periphery of the field becomes progressively blurrier, but the decline in image sharpness is very

How About a 6.5×32 in the Same Format?

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gentle and gradual. The main off-axis aberration is field curvature. While it was pretty clear from the get-go that the Opticron Adventurer T was well collimated, as evidenced by the wonderful depth perception I experienced after merging the images, I did confirm this by testing on a bright star at night and it passed. Looking at a decidedly pinkish full Moon rising low in the eastern sky, the image was bright and sharp across the majority of the field. As the Moon was moved off axis toward the field stop, I did notice a significant brightness drop off at the edges. Star fields were presented really well in the Opticron too, with stars remaining acceptably small and sharp across most of the field. Like many other binoculars I’ve showcased in the past, off axis aberrations are more pronounced panning the instrument vertically than horizontally. This will make a very decent stargazing bino for those who like to use smaller instruments. To say that I’m impressed with this little binocular would be quite an understatement. For the ridiculously low price I paid for it, the Opticron Adventurer 8×32 T WP performed WAY ABOVE expectations. It may be an inexpensive binocular, but boy does it perform! It’s lovely wide field, sharp optics and palpable stereopsis will allure many. And while it’s no Habicht, it gets my highest recommendation as arguably one of the most charming instruments I’ve had the pleasure of reviewing.

How About a 6.5×32 in the Same Format? Opticron also market a lower power sibling to the 8× model in the form of the 6.5×32 Adventurer T WP. Since many of the basic features on both the 8×32 and the 6.5×32 are identical, it provided a good opportunity to investigate a phenomenon known as depth of field, and the factors which might govern its behavior, which I shall elaborate on shortly. For now, I want to briefly summarize my findings of the 6.5×32 in relation to the 8× glass in the same series. The close focus at infinity on the 6.5× and 8× instruments were 33.9 and 44 yards, respectively. Theory predicts that the 6.5× glass will have a 8^2/6.5^2 = 1.51× greater focus depth. Plugging in the actual numbers yields 44^2/33.9^2 =1.68. Not too bad at all! Like the 8×32 model, the 6.5× glass showed excellent control of internal reflections, diffused light and diffraction spikes (i.e. none seen). Collimation was good as tested under the stars and also by checking a horizontal electricity cable in the distance. Having a look at the exit pupils, I noted only slight truncation in the left barrel, but in general, the results were very good. The first big surprise for me was its much superior glare suppression compared with the 8×32 model. For some reason that still escapes me, the 6.5× produced noticeably higher contrast images than its 8× sibling. I can only surmise that newer or better coatings were applied to these units at some time. Veiling glare was also much better controlled in the 6.5× unit. Eye relief is good: I was able to image the entire field with my glasses by rolling down the rubber eyecups, but it’s a fairly tight squeeze! Close focus was measured at just over 2.5 m, considerably better than the advertised 3  m setting. The 6.5×32 delivers a huge field of view  – fully 9.2 angular

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degrees! The sweet spot is quite large too, remaining very sharp in the inner 60% or so of the field. After that, mild field curvature sets in, becoming progressively more severe as one approaches the field edges. To my eye, about 75% of the field was acceptably sharp, with more pronounced blurring occurring in the last 25% before hitting the field stops. Sometimes I would notice a ‘fishbowl’ effect while panning large swathes of landscape. The image is very bright; noticeably brighter than the 8× glass in fact, especially in low light conditions, at and after sunset. Color correction is excellent in the center but does show a bit of lateral color as the eyes are moved off axis, but it was no more than I’ve seen in instruments costing ten times its retail cost. In terms of color balance, I judged the image as quite neutral. The image through the Adventurer T WP 6.5×32 is very stable and quite immersive. I can easily understand why an instrument like this would be ideal for a younger individual or an older observer wishing to minimize image shake while glassing. For me though, I felt the 6.5× lacked those little details I’ve come to pick up more easily in 8× and 10× instruments. In other words, it lacked a little bit of reach. But that’s an entirely personal judgement and your mileage may vary. The Opticron Adventurer T WP 6.5×32 is an excellent bargain for the rock bottom price paid. It performs very well indeed, and should delight the owner with sharp, contrast-rich details in a very impressive and immersive field of view. Some folk will find the field curvature in the outer field to be a bit distracting. Its minimum IPD of 53 mm will make it especially attractive to those who have smaller faces, and the ultra-stable views at 6.5× will likely delight individuals who suffer from significant handshake. While I’m at it, Oberwerk market a very nicely made 6.5×32 Porro prism binocular offering a wide 8-degree field of view. Weighing only 485 g, the Oberwerk LW 6.5×32 offers a great IPD range from 51 mm all the way to 74 mm, making it ideal for smaller faces. The twist-up eye cups stay in place well and offer an impressive 19 mm of eye relief, so even those wearing eyeglasses can enjoy the full field. The chassis is covered in a sand brown rubber armoring with excellent grip. It’s also waterproof and nitrogen purged – something almost unheard of in this price range. Optically, it’s received very high praise from customers and professional reviewers alike, especially when you factor in its budget price of $84.95. Though it doesn’t employ ED glass, it still achieves a high level of optical quality thanks to the use of the Bak4 Porro prisms which deliver a bright, crisp image inside a generously large sweet spot. There is some fall-off in image quality at the edge of the field but it’s nowhere near as pronounced as on the Opticron Adventurer WP 6.5×32. This is a near ideal binocular for hikers and general nature enthusiasts who don’t want to spend big money on optics but who still enjoy great views nonetheless. Check it out at Oberwerk.com.

A Sweet Deal from Nikon

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A Sweet Deal from Nikon

The Nikon Aculon A211 7×35

While it is generally true that you get what you pay for, it’s also true that you can pick up very decent optics for not a lot of money. I was very much reminded of this when I test drove the Nikon Aculon A211 7×35. This is another Porro prism binocular from Nikon having a good black rubber armoring, twist-up eye cups and a large central focus wheel. Though it’s not quite as well armored as Nikon’s more expensive and waterproof Action EX 7×35, my tests showed marginally better off-axis performance than it, possibly attributed to the aspherical lens elements employed in the design of the Aculon. At 642 g, this is not a heavy binocular. Indeed, I had no trouble carrying it round my neck for several hours while completing a 10 km trek near my home. The instrument is multicoated ensuring a high light transmission. Contrast is very good too. But what’s most impressive is its huge field of view: 9.3 angular degrees. I found that the Aculon had a small amount of glare when the eye cups were fully extended upwards but I was really surprised to discover that I could comfortably access the entire field of view without glasses when they were fully retracted! This will reduce the wear on the eyecups so extending their functional longevity. But it also had the effect of removing much of the glare I encountered in the open air. The focus is smooth and easy to turn with no backlash or free play. Indeed, of all the different brands of binoculars I’ve tested over the years, Nikon focus wheels have been consistently excellent. The ease with which I could move the focus wheel made this instrument a very enjoyable birding binocular. Indeed, I spent some time watching flocks of Long Tailed Tits flit from tree to tree across the valley. Their mode of flight – in stops and starts – reminded me very much of the way Wagtails navigate during the warmer months of the year. It was so easy to keep up with them, even as they moved off into the distance. The impressive depth of field meant refocusing was an infrequent affair. And that’s got to be a good thing for any birder.

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The enhanced 3D views through the Nikon Aculon A211 were very memorable, especially when scanning for signs of life inside a densely forested patch near my home. The field curvature actually helps keep closer objects at the bottom part of the field tightly in focus, creating a heightened sense of spatial awareness. This little 7×35 was a much better fit in my hands than the larger 8×42 Aculon I tested prior to acquiring this smaller 7×35. Does it have any flaws? Yes. When I turned the binocular on a bright streetlamp after dark, I picked up significant internal reflections. It was the same when I glassed a bright, waning gibbous Moon. Bothersome? Yes, a little, but didn’t really detract from the lovely, relaxed views I enjoyed during the day. And while the internal reflections detract somewhat from the aesthetic of Moon watching, it’s quite an impressive stargazing binocular. By studying the image of the bright, first magnitude star Rigel, I could see that field curvature and coma are strongly apparent near the field stops but to be honest, there is plenty enough field of view to thoroughly enjoy the view. Lateral color was also strong at the edge of the field but nowhere near as bad as what I saw testing the larger 8×42 Aculon A211. I spent 30 min enjoying the glories of the Winter sky on Christmas Day 2022. Orion looked magnificent riding high on the meridian, sweeping east into Monoceros where the binocular easily showed the somewhat overlapping NGC 237 and NGC 2244 and even the 8th magnitude M50 to the south was clearly discerned. I also enjoyed sweeping up the three Messier open clusters high overhead in Auriga. The large, expansive field of the little Nikon Aculon 7×35 made light work of framing all of them inside the same field. I spent some time in a zero-gravity chair sweeping through the wonders of Perseus, Cassiopeia and Cygnus, now sinking low into the northwest sky. For a binocular that you can acquire for about $100, it’s probably a best  buy in my opinion. It does lots of activities well and is sheer fun to use. If you’re on a tight budget and want very decent optical performance, go check them out.

More Sophisticated Porro Prism Binoculars Porro prism binoculars have received quite a bit of bad press in recent years. In surveying some of the literature, I’ve read that they’re heavy and unwieldy, lack water-and fog-proofing, and are more prone to misalignment of the optical elements than their roof prism counterparts. Others seem to have dismissed them purely on aesthetic grounds, citing their ‘ugliness’ as a reason to reject them. How shallow is that? But after extensively testing a thoroughly modern Porro prism binocular from Opticron – the Savanna 8×30 – I’ve discovered that many of these assumptions are either misleading or totally false. Let’s begin by listing some of the key advantages of porro prism binoculars. 1. They are much more economical to manufacture to a high standard than roofs. 2. They have much more forgiving design tolerances than roof prism binoculars.

More Sophisticated Porro Prism Binoculars

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3. They offer naturally brighter images, owing to fewer reflections through porro prisms 4. They offer very wide fields of view with simpler eyepiece designs 5. They throw up much more pronounced 3D or stereoscopic images than their roof prism counterparts and thus reveal more dimensionality in their images. Having said all that, this new model offered by Opticron promises to dispel many of the traditional reasons why porro prism binoculars have fallen out of favor with birders, hunters and outdoor enthusiasts. To see why, read on.

A thoroughly modernized Porro: the Opticron Savanna 8×30

The first thing that grabbed my attention was the feather light weight of the Opticron Savanna 8×30. Tipping the scales at just 458 g (without the strap), this is actually one of the lighter models on the market. For example, the Nikon Monarch HG 8×30 comes in at only 8 g less! The chassis is covered in a nicely textured rubber armoring that feels quite spongy to the touch, protecting the instrument from accidental knocks and bumps. The central hinge is nice and rigid, keeping my optimal IPD even after taking it out of its tightly fitting soft carry case many times during my tests. The eyecups are strong and are of good quality and twist up like most roof prism models. This is a departure from the fold-down rubber eyecups I’ve seen on a few other Porro prism designs. They click rigidly into place, but there is no provision to set them at an intermediary position. I rather like two stage eyecups like this though, as I’ve rarely found an intermediate detent in any binocular that conveys a more comfortable view. The eye relief is quite generous though. I was able to image the entire field comfortably using eyeglasses.

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The focuser is very large and easily accessed. Movement is smooth and firm with a little bit of play. What’s more, the focuser only rotates through about three quarters of a full revolution in order to go from one end of its focus travel to the other. Close focus was measured to be 2.8  m, a little closer than the advertised 3  m. It also focuses a wee bit beyond infinity, useful for snapping edge of field objects into tighter focus. The ocular field lenses are large (21  mm in diameter), making eye placement easier to achieve and comfortable to place one’s eyes against. The diopter compensation ring is located under the right ocular lens. It moves with a nice amount of rigidity. The external focuser is fashioned from aluminum which affords good tensile strength. Examining the progress of its motions, I was delighted to see there was zero wobble as it was racked in and out of focus. The binocular is advertised as waterproof and fog proof (nitrogen purged), so I assume it’s o ring sealed. This may come as a surprise to roof prism fans, but surveying the market, there are several other Porro models that now claim the same. One very welcome feature is the minimum inter-pupillary distance of 50 mm, making it eminently suitable for those of us who have smaller faces. These will work brilliantly with kids! The small 30 mm objective lenses are very deeply recessed. This is a very welcome feature, as it protects the objective lenses from rain, dust and stray light. My experiences over the last several years has taught me that models without very deeply recessed objectives generally display higher levels of glare during field use. In the hands, the Opticron Savanna 8×30 feels great. There are plenty of places on its nicely contoured body to wrap your fingers round. Indeed, I’ve not held a more comfortable binocular in quite some time! Overall, this appears to be a very nicely designed Porro prism binocular, incorporating many of the great features found in roofs costing substantially more! Now, let’s talk about optics. The binocular arrived in good collimation, as judged in daylight testing and by examining the bright star Arcturus, defocusing it using the right eye diopter. By directing a beam of intensely bright light into the binocular objectives, I was able to verify that there were no annoying internal reflections, diffraction spikes and only a very small amount of diffused light around the light source. The result was just as good, in fact, as a highly-rated roof prism control binocular I used  – the GPO Passion ED 10×32. I measured the effective aperture as effectively 30 mm by directing a beam of light through the ocular lens and measuring the diameter of the emerging disc of light. There were also no internal reflections when I tuned the binocular on a bright sodium street light after dark. The Opticron Savanna 8×30 throws up a very impressive image. The sweet spot covers about 80% of the field, with mild field curvature setting in as the target was moved to the edge of the field. Contrast is excellent too. Comparing it to the less expensive Adventurer T WP 8×32 Porro prism binocular, the Savanna displayed far less glare. Veiling glare was also far less pronounced in the Savanna too but not quite as well controlled as in the GPO 10×32 binocular costing three times its modest price tag. Though the field of view is smaller than in the Adventurer T WP 8×32 (8.1 degrees), it’s much cleaner, with nicer edges and a clearly defined field stop.

The Remarkable Phenomenon of Stereopsis

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The Savanna 8×30 image is very bright and sharp within its generously large sweet spot. In careful side-by-side tests with my GPO 10×32 Passion ED, I judged the images as equally sharp (or maybe a tad sharper in the Savanna porro) in the middle of the field, but fell short of the roof prism bino from about 50% of the way from the center to the field stops. In addition, the color tone of the Savanna 8×30 was very neutral in comparison to the warmer colors garnered with the GPO. Chromatic aberration was not seen on axis, and only a trace was detected off axis while looking at denuded branches of trees against a bright, overcast sky. This shows, once again, that a good binocular needn’t employ ED glass to deliver a really good image. Indeed, with just a few exceptions, all of the top Porro models now available don’t employ ED glass. In yet another test, I ordered up a classic Opticron Dioptron 8×32, a vintage Japanese-made instrument dating to the late 1990s. I was amazed to discover how much brighter the Chinese-made Savanna 8×30 was in comparison. Sporting a field of view of 8.25 angular degrees, the Dioptron also enjoys a large sweet spot but once outside it, the images of stars rapidly deteriorated as they were moved towards the field stops. In comparison, the 7.5 degree field of the Savanna 8×30 kept those same stars under better control even near the edge of the field. Though the Dioptron is also fully multi-coated, it showed some prominent internal reflections, unlike the Savanna, and daylight images were noticeably yellowed (warm) in comparison to the much more natural color tones served up by the modern Savanna binocular. Glare was also much better controlled in the Savanna in comparison to the classic Dioptron 8×32. Collectively, these tests convinced me that great advances in coating technology have occurred in the last two decades, with even low cost ‘econo’ binos serving up noticeably brighter and more contrasted images than some of the best Porro prism binoculars available from the late twentieth century.

The Remarkable Phenomenon of Stereopsis One of the things that struck me as being obvious and visually striking in the Opticron Savanna 8×30, was its ability to generate wonderful depth perception, or stereopsis, as it’s referred to in the technical literature. Focus the binocular in the middle distance and objects remain razor sharp all the way to infinity. What does that translate to in field use? Less frequent focusing. Looking at some conifer tree trunks lying beyond my back garden, and comparing the view in a few roof prism models, revealed the total superiority of the Savanna Porro in conveying three-­ dimensional, spatial information or contouring of the tree trunks in relation to each other. The effect becomes less pronounced at distance though. But for walks in the woods, where trees litter the landscape both near and far away, I can’t think of a better instrument than a small high-quality Porro like this to enjoy those views! Indeed, I’ve now come to see this effect as adding valuable information to the binocular image – just as our eyes were designed to do.

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The old adage is certainly true; you have to go to great lengths to make a roof prism binocular as good as Porro prism designs. The quirky little Savanna 8×30 takes a tried and trusted optical design and puts a thoroughly modern accent on it. For the modest price of just over £100, you get an instrument that has excellent optics and ergonomics. It totally smashes the stereotype of Porro prism binoculars being big and clunky too. And it’s quite a good-looking binocular, don’t you think? My experiences with this lovely little instrument has consolidated my conviction that Porro prism binoculars will be my instruments of choice in the compact-size format, with their unparalleled 3D-enhanced images and brilliant, sharp, high contrast optics. I would highly recommend this instrument to savvy binocular enthusiasts wanting to get the absolute maximum bang for buck. I would also recommend the instrument or its lower power sibling – the Savanna 6×30 – for younger individuals or adults with smaller faces. Rest assured, it will embarrass roof prism designs costing a few hundred pounds and the solid 10-year warranty from Opticron will put your mind at ease. The Savanna also comes in a handy 6×30 format, which offers more stable views for shakier hands, greater filed depth  – arising mainly from its lower magnification – and a larger field of view. Indeed, the Opticron Savanna is but one incarnation of a number of other highly successful compact Porro prisms binoculars offered by Koya (in their YF series), Vortex Raptors and the Leopold Yosemites. Be sure to check some of these models out if you fancy using quality Porro prism binoculars for regular glassing.

 conomical Compact Binocular from Nikon: The Prostaff P3 E and P7 Range In the summer of 2022, Nikon launched a new range of low priced, entry-level models packed full of ergonomic and optical features that provide a very pleasant viewing experience. Both the Prostaff P3 and P7 range include 8× and 10×30 models. The Prostaff P3 8×30 delivers a very wide field of view – 8.7 degrees in fact. The 10× model, in contrast, offers up a 6.6 degree field. Both models are waterproof to a depth of 1 meter for 10 min and are filled with dry nitrogen gas to prevent internal fogging in cold weather. The P3 models have fully multicoated optics and silvered roof prisms to deliver brighter images. The specifications do not indicate that they are phase coated though. Their light weight (under 500 g) makes them very portable. They also feature well-made twist up eyecups and decent eye relief (15.4 mm) for eyeglass wearers.

An Amazing Performer from Svbony: The SV202 ED 8×32

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The P7s are an upgraded version of the P3s, with similar eye relief, field of view and weight, but have dielectric and phase corrected optics which will deliver brighter images with finer contrast than the P3. They also have a scratch resistant and hydrophobic coating applied to the outer lenses for extra protection from the elements, as well as a locking diopter. If your budget can stretch to $50 more, the extra features in the P7 models are well worth the upgrade from the P3s. Having said all of this some users report that these new economically priced roof prism binoculars from Nikon have just too many plastic parts and feel a bit cheap in the hand. One buyer of the Nikon Prostaff P7 8×30 reported that the plastic diopter adjustment that is meant to lock into place broke after just a few days of use. I think Nikon would have done far better to stick with a simple non-locking diopter compensation ring under the right eyepiece, especially at this price point. The P3 30 mm models retail for about $140 whereas the more sophisticated P7, for under $190.

An Amazing Performer from Svbony: The SV202 ED 8×32 Make no mistake about it; we live in a golden age for buying binoculars. Never before has the consumer had so much choice available, thanks to incredible advances in optical technology which has given many other individuals access to very decent optics for a small financial outlay. In recent years, new coating technologies have greatly increased light transmission and image sharpness, to such an extent that even the budget models now available can and do outperform many top-rated models offered only a few decades ago. In addition, the incorporation of extra low dispersion (ED) glass is now common even in inexpensive models, which, if executed properly, promises to cut chromatic aberration and increase image contrast still more. As I’ve commented elsewhere, the 8×32 format is the new 8×42, as evidenced by the offering of the former by both mass market and premium binocular manufacturers alike. This is in no doubt attributed to their lower mass, improved ergonomics and very efficient light transmission, as well as their perfect suitability during bright daylight but also well into low light situations encountered at the earlier stages of dusk and dawn. After enjoying many nice pocket binoculars for a few years, I gradually came to realize that the 8×32 format or thereabouts is probably my favorite of all, owing to their more immersive images, compactness and smaller exit pupil (4 mm), which uses the best part of your eye to analyze the binocular image.

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The Svbony SV 202 8×32 ED

While many entry-level ED models are priced in the £250 to £300 range, I became very intrigued by a less well-known manufacturer, Svbony, a Hong Kong-­ based optics firm that has recently marketed a compact and mid-size model – an 8×32 and 10×42 – chock full of advanced features. But what really piqued my interest was that Amazon UK were offering the 8×32 ED model for under $100, inclusive of delivery! On paper at least, he Svbony 8×32 ED seemed to offer a number of advanced optical features that I simply wouldn’t have expected in a model at this price point, but having another binocular available – the Celestron Trailseeker 8×32 (retail price $280) – that also possesses many of the same features – I was able to conduct an in-depth study of how the Svbony ED binocular compared with it. No doubt you’ve heard that possessing a Magnesium alloy frame is a feature only common to upper-tier binocular models, I would like to take this opportunity to put this urban myth to bed, once and for all. Since both the Svbony and the Celestron Trailseeker models feature a magnesium body in this low price category, having this design feature is no longer the preserve of the best models but is now commonly available even in much more economically priced products. The Celestron Trailseeker has a large plastic focuser that becomes very hard to move in winter owing to the solidification of the grease used in its gearing. But in warm weather, it becomes much easier to turn. In contrast, the lower priced Svbony 8×32 ED has a much higher quality metal focus wheel, which is much smoother and easier to turn. Taking just one and a half revolutions to go from one extreme of its focus travel to the other, I would describe it as slow to progressive in speed, so not especially suited to either birding or hunting – more of a general-purpose instrument than anything else.

An Amazing Performer from Svbony: The SV202 ED 8×32

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The Svbony 8×32 ED (right) and the Celestron Trailseeker 8×32 (left)

Turning now to the diopter ring located under the right ocular in both models, the Svbony’s metal diopter ring is better designed than the plastic one found on the Trailseeker. Looking closely at the Svbony diopter, you can see that the markings are easier to make out, helping the user achieve his or her optimum position better. And just like the Trailseeker, the Svbony diopter ring is stiff and thus will not get nudged out of position so easily during field use. Looking next at the quality of the eyecups, I was delighted to see that the Svbony had good, high-quality rubber-over-metal twist up cups, pretty much identical in quality to those found on the more expensive Trailseeker. What’s more, they stay rigidly locked in place when fully extended. Yet again, that the Svbony possessed such high-quality eye cups was a pleasant surprise to me, as I was not expecting anything as good as that on a compact binocular costing less than $100. The matt black textured rubber armoring on the Svbony is a little bit more grippy than the Trailseeker too and the ribbing at the side of the former reminds me very much of the armoring found on the Zeiss Terra ED models I’ve sampled. The objectives on both the Svbony and the Trailseeker are equally well recessed to protect the glass from dust, rain and peripheral light. The anti-reflective coatings look to be completely different though, with the Trailseeker having a standard greenish reflection in bright daylight, as opposed to the more subdued purple hues seen on the Svbony.

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The lower-priced Svbony model has a higher quality dioptre ring compared with the Celestron Trailseeker

Overall, the Svbony 8×32 ED feels slightly lighter and more comfortable to use than the Celestron Trailseeker 8×32, which is a bit more ‘clunky’ in comparison, at least in my medium sized hands. That, together with the noticeably better focus wheel and diopter compensation ring on the former means that, from a purely ergonomic perspective, the lower-priced Svbony is the clear winner. So how well would the £99.99 Svbony 8×32 ED fare in comparison to the Celestron Trailseeker 8×32? My efforts confirmed that the Svbony also passes this test with flying colors! Specifically, the image was devoid of any significant internal reflections and with no diffused light around the beam, which often betrays the use of lower quality optical components introduced into the optical train. What is more, while the Trailseeker did show a weak diffraction spike, the Svbony had none. Indeed, I would place the Svbony slightly ahead of the Trailseeker, based solely on the flashlight test. So far so very good! But the good news only continued when I performed a daylight comparison test of both the Svbony ED 8×32 and the Celestron Trailseeker 8×32. While both

A High Power Compact Binocular from Vortex

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models have effectively the same field of view (7.87 degrees), I felt that the Svbony provided a slightly sharper image than the Celestron, with better contrast and improved control over veiling glare. Both instruments have a large sweet spot but edge of field performance was a little soft in both models, as was the degree of field curvature seen. Chromatic aberration, although quite low in the Trailseeker, was better handled in the Svbony under the same conditions. Whatever ED glass elements are present in the Svbony, it seemed to be doing its job well. Close focus is just under two meters (1.98 m measured). Another way to ascertain whether similar coating technologies were applied to both the Svbony and the Celestron Trailseeker, is to perform a low light test by comparing the brightness of the image in both instruments at dusk. On paper, I expected both to behave rather similarly, and that is exactly the result I achieved. Both 32 mm models produced a more or less equally bright image, with perhaps the nod going to the Svbony! Examining the 4  mm diameter exit pupils on the Svbony showed nice, round pupils with no signs of truncation. There was also a nice periphery of blackness immediately around both pupils, which contributes to the high contrast images I detected during my daylight tests. The Svbony 8×32 ED was a very eye-opening and pleasant experience. In terms of both optical and mechanical properties, it proved superior to the Celestron Trailseeker. Indeed, I would put the Svbony more on par with the new Celestron Trailseeker ED. The very few realistic reviews I’ve seen of the Svbony 8×32 ED claim that it performs like models double or triple the price; a sentiment that I wholeheartedly agree with. And at a retail price of less than $100, there is very little in this binocular that I can find fault with.

A High Power Compact Binocular from Vortex The US-based company Vortex, headquartered in Barneveld, Wisconisin, has enjoyed great success in bringing to market an extraordinary range of binoculars that offer exceptional value for money. Arguably their most successful range are the Diamondback series of binoculars, which has undergone two upgrades from the original models which hit the shelves back in 2014. The first upgrade came in 2016, which shaved off a significant amount of weight over the first-generation models, while the latest models introduced in 2019 gained the HD status, with improved optical performance. I ordered up the 10×32 model for field testing and I can report that it’s an excellent buy for the budget conscious.

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The Vortex Diamondback HD 10×32 is an ergonomic delight to handle

Weighing in at only 450 g, the 10×32 HD sports nicely-made twist up eyecups with one intermediate position, and which hold their positions rigidly. The focuser is very smooth and backlash free. The focus wheel is slow, taking one and three quarter clockwise turns to go from one end of its focus travel to the other. The excellent green rubber armoring is neither too thick or two thin and has a decent grip to help stabilize the instrument in your hands. Close focus is about 2 meters. All the HD models come with fully multicoated optics, phase corrected BaK4 Schmidt Pechan roof prisms and dielectric coatings which help deliver a bright and color accurate image. They are also argon purged and o ring sealed rendering the Diamondback HDs waterproof and fog proof. Optically, the Diamondback HD 10×32 delivers a crisp, high-contrast image in a very generous field of view of 6.5 angular degrees – quite good for this compact class. The sweet spot is quite generous and even at the edges of the field, distortion is quite mild. It does have a few minor shortcomings, such as showing a bit of glare when pointed in the direction of bright sunlight, but much of this can be minimized simply by shading the objectives using your outstretched hand. It can also show some mild color fringing when viewing high contrast targets against a bright overcast sky. Finally, the eye relief is a little short – just 14 mm – making it well-nigh impossible for eyeglass wearers to take in the entire field. That said, I found it to be an excellent low-weight binocular for spotting targets that are difficult to see using 8× glasses. Having undergone many significant improvements over the years, the Diamondback HDs are certainly well thought through products that offer exceptional value for money. I would be quite happy using a Diamondback HD as my

Neat, High-Performance 30 mm Roofs from Nikon

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main binocular, as to my eye they deliver maybe 85% of what a top-rated modern binocular can offer but at a price ten times lower ($220) than the most expensive 10×32 on the market today. The Diamondback 10×32 HD also comes with an impressive array of accessories, including a quality clamshell case that zips closed, a microfiber lens cleaning cloth, a well-illustrated out instruction manual, as well as a good quality neck strap and that all -important VIP warranty- probably the best in the industry. This means that whatever happens to your Diamondback HD, Vortex will repair or replace the instrument at no cost to you and with no questions asked. That alone makes them highly popular with birders, hunters and nature enthusiasts alike.

Neat, High-Performance 30 mm Roofs from Nikon Nikon has upped its game with the launch in September 2021 of 7 new Monarch binoculars encompassing their M5 and M7 range. Sitting between their entry-level Prostaff and top-tier EDG ranges, the Nikon Monarch M7 series includes 8×30 and 10×30 binoculars that are designed to provide high-quality optics and durability for outdoor enthusiasts and birdwatchers. Both the 8×30 and 10×30 models feature a compact and lightweight design, making them easy to carry on outdoor adventures. They also have a durable, rubber-­ armored body that provides a secure grip, even in wet conditions. Both Monarch M7 binoculars are equipped with a dielectric high-reflective multilayer prism coating and a phase-correction coating that helps to deliver bright, sharp, and clear images with accurate color representation. The lenses are also fully multicoated to provide maximum light transmission, even in low-light conditions. Compared to the original Monarch 7s, the newly-vamped M7s have a sleeker body design and a locking diopter situated under the right ocular. The new M7 models also feature hydrophobic coatings applied to the outer lenses. The binoculars have a wide field of view – 8.3 degrees for the 8×30 M7 and 6.7 degrees for the 10×30 – making it easier to locate and track subjects, and a long eye relief, making them comfortable to use, even for people wearing eyeglasses. The eyecups are adjustable, allowing for a custom fit and comfortable viewing. Both models are also waterproof and fog proof, making them suitable for use in various weather conditions. They come with a neck strap and a carrying case for convenient storage and transportation. The first-generation Nikon Monarch 7 8×30 proved to be a very popular with birders and outdoor enthusiasts alike owing to the impressive field of view, great sharpness and color correction and feather light weight. These newer M7 models promise even better ergonomics, though I’m not sure whether the inclusion of a lockable diopter is a real improvement. Maybe time will tell. Overall, the Nikon Monarch M7 8×30 and 10×30 binoculars are excellent choices for outdoor enthusiasts and birdwatchers who are looking for high-quality, durable binoculars that can provide bright and clear images with accurate color representation.

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A Modern High-Performance Binocular from Oberwerk

The handsome chassis of the Oberwerk SE 8×32 ED

I first got wind of the new Oberwerk binocular from online forums like Cloudy Nights and Birdforum, where it was generating quite a bit of excitement, especially from Porro prism fans. The founder and CEO of Oberwerk, Keven Busarow, seems to have a penchant for resurrecting cool instruments from the past. The company’s highly lauded Oberwerk 20×65 ED Deluxe is one such example, which Busarow described in his own words to be, “our take on the venerable Takahashi Astronomer 22×60.” Here at least, Oberwerk appears to have been vindicated, judging by the sheer number of positive reviews and comments made about it over the years since its roll-out. The Oberwerk SE 8×42 ED is the culmination of Busarow’s latest efforts to cultivate a binocular that seems to have held legendary status among binocular collectors just a few short decades ago, the Nikon Superior E (SE) line of advanced Japanese-made Porro prism binoculars that flourished for a while before being discontinued back in 2014. Since then, these fine instruments, which included 8×32, 10×42 and 12×50 models, have become as rare as hens’ teeth, and up to recently, commanding eye-watering sums on auction sites whenever they show up. Oberwerk  found a good optical design in a Porro,  and developed  a product that offers similar levels of performance at a price that won’t break the bank. Did they succeed? Yes, I think so! The instrument arrived well packaged and double-boxed. The binocular was stored inside a very attractive green canvas padded case. I really like it as it doubles up as a fishing bag. All the accessories were there too – the neck strap, lens cleaning cloth etc. Oberwerk also included a test card showing that the instrument was checked before dispatching to me. There was no instruction manual but a card accompanying the instrument has a link to Oberwerk’s website where you can find excellent start-up instructions.

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This is one chunky instrument, tipping the scales at 798 g – the heaviest 8×32 that I’ve personally encountered and much more in keeping with instruments in the 42 mm aperture class. That said, it has a beautiful, solid feel in the hands, the central hinge being good and tight, the focus wheel moving smoothly, the eye cups twisting up and down nicely. The instrument came with the thick rubber rain guard and objective lens covered attached. These were of unusually high quality, at least on a binocular that retails for just under $250. They fit on very firmly, so there’s little chance of losing them by accident. While the rubber rain guard is tetherable to the neck strap, there is no such provision for the objective caps. That wasn’t an issue for me though, as I hardly ever use them, except for storage purposes. I also really liked the antireflection coatings on the Oberwerk SE 8×32 ED. They are immaculately applied and give a pink hue in daylight. The Oberwerk SE 8×32 ED is a handsome binocular. With an aluminum chassis covered in a thick green rubber armoring, the instrument feels very secure in the hands. Like the Nikon SE, it has bulky shoulders where the prisms are located, which gives it a very distinctive look. The rubber armoring around the objectives has a rougher texture than that of the upper body, no doubt to assist the fingers in gripping the barrels. The objective lenses are exceptionally well protected thanks to about an inch of barrel overhang. This affords them excellent protection against rain, dust and the encroach of stray light. The sides of the barrels have upraised ribs to allow the palms of one’s hands to better grip the instrument. The twist up eye cups are constructed from machined aluminum and are covered with soft rubber which are very comfortable when pressed against the eyes. There are three intermediate positions between fully retracted and fully extended. At each position the cups lock securely into place. Eye relief is very generous, especially for a 32 mm instrument. I was able to access the entire field using glasses while the eyecups were fully retracted. The centrally placed focus wheel is distinctly different from the original Nikon SE in that it is placed further away from the eyecups. It’s very easily and comfortably accessed once you wrap your hands round the barrels, when the fingers can naturally fall on its prominent ridges. It turns smoothly with a fair amount of friction but my sample developed a little bit of play after a few weeks of use – not that it bothered me that much. Just shy of 1.5 revolutions anticlockwise takes you from closest focus (measured at 2.99 m) to infinity and a little bit beyond. The diopter compensation is achieved by rotating a small plastic ring under the right ocular. It moves smoothly but I would have liked to have seen a wee bit more tension to avoid it accidentally wandering in field use. For example, while out on a forest walk, I encountered some light rain which forced me to place the rubber rain guard on quickly. Once the shower passed, I began to struggle getting it off again (yes it’s that tight!), but that physical effort was enough to move the diopter slightly out of its desired position. Though it’s quite a heavy binocular for its aperture class, the supplied padded neoprene strap helped greatly to lighten the load. Handling the instrument is a real joy though. Because more of the weight is located towards the eyepiece end of the

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binocular, its center of gravity is tipped closer to your body, making prolonged viewing more comfortable. Indeed, Zeiss employ the same idea – ergobalance – on their flagship SF models. I certainly never felt any strain or fatigue while using the instrument in the field for several hours at a time. So how did it perform optically? Performing my bright light torch test to examine the images from a bright light source, I was pleased to see a few very minor internal reflections with no diffused light around the source. This is a binocular that will perform well at night watching brightly lit scenes. My next test involved looking at the exit pupils and the results were excellent: perfectly round pupils and no false pupils or stray light in their vicinity. In fact, the Oberwerk SE served up one of the best pupil images I’ve personally seen in 5 years of testing out binoculars! The day the instrument arrived was quite overcast and dull – not the best light to glass, but certainly the best conditions to ferret out any issues the binocular might have had. The images were incredibly sharp in the center and also on the edges, with bright, vivid colors, excellent contrast and superb control of glare. Examining a vertically erected scaffold pole, I was delighted to see very mild pincushion (positive) distortion in the outer part of the field. I was also thrilled to see the well-­ defined field stops with the eyecups fully extended. Unlike the Nikon SE, which was widely reported to have black outs owing to spherical aberration of the exit pupil, this instrument produced none. The view was, to all intents and purposes, sensibly perfect. Images snap to a very precise focus with no ambiguity. But what really amazed me was its complete lack of chromatic aberration! This instrument employs Chinese FK-61 low dispersion glass, roughly equivalent to Ohara FPL-51, but it was more than enough to cut out color fringing both in the center of the images and also in the outer field. Comparing it with the venerable Nikon E II 8×30, which shows some lateral color on high contrast targets like the branches of trees set against an overcast grey sky. The Oberwerk SE showed virtually none, save for the merest trace right at the field stops. Indeed, comparing the views of both instruments in a variety of lighting conditions, I formed the impression that the Oberwerk was just slightly sharper with a little better contrast and more pronounced colour ‘pop’. The biggest difference between the two was the significantly wider field of view in the Nikon E II (8,8 degrees vs 8.2 degrees). That’s quite a result for a $250 binocular!

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The Oberwerk SE 8×32 ED (left) versus the Nikon EII 8×30 (right)

On another afternoon, I chanced upon a wonderful apparition on the road leading to Culcreuch Castle. This time of year, Chaffinches, Bullfinches and other species forage in the leaflitter at the sides of the road, with many of them hopping onto the road in search of tukka. About 25 yards ahead of me, I watched in sheer amazement as a beautiful Redwing began to bathe in a water-filled pothole. Standing dead still, I brought the Oberwerk SE to my eyes and focused in on the scene. The image was superb! I could see its beautiful dark brown spots adorning its white belly, its striking red flanks and underwings and the creamy white stripe over its eyes. The contrast against the dark tarmacadam made it all the more compelling but I also became acutely aware of the bumps and depressions on the road, both in front and beyond the bathing Redwing- a consequence of the binocular’s prominent stereopsis (3D effects) at moderate distances. Centering the bright star, Procyon, in the field of view, I was delighted to see that it remained a tightly focused pinpoint nearly all the way to the field stops. I would estimate that in the last 10% of the field, the effects of very mild field curvature and a trace of astigmatism (elongation) could be made out with a concentrated gaze. This is an excellent result. I must report though that there is some modest illumination drop off as the star approached the field stops. Comparing it to the Nikon E II 8×30, the same tests showed more pronounced field curvature starting in the outer 20% of the field, becoming distinctly distorted at the field edges. Turning to the full Moon, I noted no chromatic aberration in the center of the field, but also crucially,

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virtually none right up to the field stops. Only the merest trace of lateral color – blue nearest the center and yellow furthest away – could be made out. The Nikon E II showed much more pronounced color at its field stops in comparison. The Oberwerk SE 8×32 ED is a phenomenal performer by day or by night. Though it was inspired by the Nikon SE, there are several significant design differences that set it apart from the famous Japanese optic: it has a significantly larger field of view, incorporates modern ED glass to improve color correction and doesn’t use field flatteners – a design characteristic I personally prefer. Yet it achieves a very high level of optical performance thanks to the incorporation of cleverly designed wide angle eyepieces. Moreover, it does not manifest the less desirable optical effects of the Nikon SE with its widely reported kidney beaning (blackouts). It’s also waterproof and fog proof, unlike the original Nikon SE binoculars, so can be used in a wider variety of outdoor conditions than the Nikon super glass. This is a first-rate birding binocular but will also serve up excellent views of the night sky. And if it gets a bit heavy to hand hold, stick it on a lightweight monopod and you’re off to the races. Mr. Busarow ought to be congratulated for bringing such a superb optic to market at a price that many folk can afford. It goes without saying that this product gets my highest possible recommendation.

A Neat Folding Compact Binocular from Bushnell

The Bushnell Forge ED 10×30. (Image Credit: Bushnell Sports Optics)

Bushnell is certainly a very well-established brand name in the sports optics industry. They recently launched their Forge line of ED roof prism binoculars packed full of attractive features, such as fully broadband multicoated optics, dielectric coatings, full weather proofing, phase corrected Schmidt Pechan roof prisms,

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ED prime glass and the company’s proprietary EXO Barrier protective coating. The 10×30 Bushnell Forge retails for $350 and tips the scales at 388 g, presented in an attractive sand-brown armored chassis which is both comfortable to grip and tactile. The diopter compensation on the little Forge 10×30 is also lockable, a feature usually reserved for more expensive optics. Owners are by and large pleasantly surprised by these binoculars, especially for the price. The 10×30 serves up a well corrected field of 6.3 degrees, not bad at all for a 10×30 compact. Views are sharp and bright with very good color correction. The sweet spot is quite generous but some critical reviewers have reported significant softening of the image near the field stops. Some other owners report having trouble adequately gripping the focus wheel as it is positioned rather oddly at the far end of the bridge and not near the eyepieces as it is in the larger models. The carry case is also far too big to snugly store the instrument. The Bushnell Forge series is also available in 8× and 10×42 formats, as well as a larger 15×56 and are covered by Bushnell’s lifetime no-fault warranty.

Two Classy Compacts from German Precision Optics (GPO) If you like well-built roof prism binoculars with impressive optics, you’d do well to check out the German Precision Optics (GPO) Passion ED 8× and 10×32. I first tested the 10×32 model, the package of which arrived with all of the same great quality accessories that delighted me in the larger HD binocular (discussed in the next chapter): I received the same neck strap, a smaller clamshell case, snugly fitting rain guard and objective lens covers, GPO-branded microfiber lens cleaning cloth, instruction manual and warranty card. It arrived in the same high quality presentation box as the larger HD model, with its unique serial number etched into the underside of the binocular and on the outside of the box. Very neat!

The GPO Passion ED 10×32 and its high-quality carry case

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Picking up the binocular and holding it, I was chuffed to see how well it fitted my hands. The narrow, single bridge allowed me to wrap my fingers round the barrels better than many other 30–32 mm model I’ve previously handled. And while the instrument has a lovely, solid feel about it, with its sturdy magnesium alloy chassis, I was very reassured by its considerably lower weight; just 500 g. The central hinge is nice and stiff, making it difficult to change the IPD on the fly. I like that. The binocular has a rather oversized central focus wheel, just like the heavier HD model, and I was relieved to see that it moved very easily and smoothly, with just one finger. It did have a small amount of play though. The professionally machined aluminum eyecups are, in my opinion, even more impressive on the Passion ED model than the HD, rigidly locking into place with one intermediate click stop. The immaculately applied rubber armoring has two textures, just like the HD, a roughly textured side armoring and a silky-smooth substrate covering the inside of the barrels. The GPO Passion ED shares many of the high-quality ergonomic features built into the more expensive HD models. The ocular and objective antireflection coatings are immaculately applied and have a fetching magenta hue when observed in broad daylight. The earliest models of these Passion ED binoculars did not have hydrophobic coatings on the objective lenses, but I was happy to hear that the latest models do in fact have this feature. The objective lenses are recessed quite deeply. I measured it at about 9 mm! Why so deep? Well, it could be to protect those objectives from the vagaries of the weather; rain, wind, and stray light. The eyecups are beautifully designed; absolutely world class! They extend upwards with one intermediate position between fully retracted and fully extended, and lock into place rigidly with a reassuring ‘click.’ This is one binocular you can safely store inside its case with the eyecups fully extended for quicker deployment. They ain’t gonna budge! Eye relief proved perfect for me, as I don’t use eyeglasses, but I think the stated value of 15 mm might be a bit optimistic, as I was not easily able to observe the full field of view keeping the eyecups down and wearing my varifocals. Unlike the more expensive HD models which have a center-locking diopter adjustment, the Passion ED presents a more cost-effective solution by returning it to under the right ocular lens. While adjusting it, I noted its excellent rigidity, rendering it very resistant to accidentally moving while in the field. I felt it was a very acceptable compromise. Furthermore, the+and – settings are clearly marked, and so it’s very easy to memorize its optimal positioning should the instrument be used by others. The oversized focus wheel is very easy to access and maneuver using one finger. It has a very grippy, texturized rubber overcoat, identical in fact to the more expensive HD models. Taking just over one complete turn to go from one extreme of its travel to the other, I would rate its speed as very fast; a good thing in my opinion, as I enjoyed using it primarily for birding, where big changes in focus position are often required following a mobile avian target. All in all, and with the possible exception of the Oberwerk SE 8×32 ED previously discussed, the build quality and handling of the Passion ED 10×32 are absolutely unrivalled in this moderate price class. GPO has clearly gone well beyond the

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call of duty in the design and execution of these new, highly advanced compact binoculars! The GPO Passion ED 10×32 came perfectly collimated. I was able to ascertain this by carefully focusing the binocular on the bright star Capella and then moving the right eye diopter to the end of its natural travel. The perfectly focused star from the left barrel was found right in the center of the defocused star diffraction pattern. I had no issues with internal reflections and stray light with this 10×32. The image of an intensely bright beam of light from my IPhone torch was clean and devoid of diffraction spikes. The exit pupils are nice and round and have little in the way of light leaks immediately around the pupil; a very good result but not quite in the same league as those found on the more expensive Passion HD 10×42. In broad daylight, the images served up by the GPO Passion ED are very impressive! It is bright and very sharp across most of the field, with very little in the way of distortion even at the field stops. Like the Passion HD model, it enjoys a very decisive snap to focus on whatever target I turn it on. The small exit pupil ensures that the best part of your eye does all the imaging. Colors are vivid and natural but to my eye it has a slightly warm tone, with greens and browns coming through very strongly. Its color correction was notably better than the Leica Trinovid HD 8×32, and I felt its sharpness and contrast were perhaps a shade better too. I’m confident that this 10×32 ED could hold its own against top-rated compact binoculars up to twice its retail value or more. Contrast is very good but not quite in the same class as the GPO Passion HD 10×42 I tested it against. Glare suppression was also impressive. Comparing it to my control binocular – a Barr & Stroud Series 5 8×42 ED – which exhibits excellent control of all types of glare, including veiling glare, the little Passion ED proved to be slightly superior to it. However, it was not quite as good in this capacity as the GPO 10×42 HD model, which exhibits the best control of glare that I have personally witnessed in any binocular. Close focus is considerably better than I had expected. The accompanying user manual claimed 2.5 m for this model, but I measured it at only 1.92 m! Color correction in the GPO Passion ED 10×32 is very impressive! Pointing the binocular into the branches of a leafless tree against a bright overcast sky, the center of the image is completely devoid of it, and even off axis, I could only coax the merest trace and only near the field stops. Returning to testing the binocular under the stars, I was able to verify just how well corrected the field of view is. Stars remain nice pinpoints a good way out towards the field stops. I attribute this excellent result to GPO’s optical engineers’ choice of field size. Six degrees is not large by modern standards so it’s easier to achieve optical excellence using standard eyepiece designs. More on this a little later. Venturing out on a freezing, misty December night to observe the full Moon, the GPO Passion ED 10×32 threw up a beautiful image. It was clean and sharp and contrasty. Secondary spectrum was virtually non-existent over most of the field, with only the extreme edges showing some weak lateral color. Field illumination was also excellent, as with the 10×42 HD, with very little in the way of brightness drop off as the bright silvery orb was moved from the center to the edge of the field.

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I also judged field distortion to be excellent in these tests too. The Moon remains razor sharp across most of the field, and only shows slight defocus at the field stops. The view through the GPO Passion ED 10×32 is very stable and immersive. On paper a field of view of 6 degrees might seem restrictive but in practice you never get that impression since the sweet spot is generously large. There are no blackouts, rolling ball effects or any other issues common to compact models sporting wider fields of view with field flatteners. This makes panning observations particularly pleasurable with this instrument. To be honest, I suspected that this would have been the case after I had put the Passion HD 10×42 through its paces. Indeed, I would hazard a guess that both binocular lines – the HD and ED – have substantially similar optical designs. As an experienced binocularist, I have no obsessive interest in very large fields of view. Indeed, in some cases those wide-angle binoculars as rather distracting and more suited to beginners than more seasoned observers. I also explored the 8×32 model in an attractive green and black armoring. Like its 10×32 sibling, it showed near identical results when I examined how it handled an intensely bright beam of white light, where it showed only very minor internal reflections and no prominent diffraction spikes. The same was true when I examined the entrance pupils of the 8×32 which showed no departures from circularity, and with plenty of good and dark space beyond them.

Enjoying the great outdoors with the GPO Passion ED 8×32

Right from the get go, I was taken by the quality of images served up by the GPO Passion ED 8×32, even during the dull overcast conditions on the afternoon the instrument arrived. The binocular serves up a very powerful optical wallop. Images

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snap to focus with no ambiguity across the vast majority of its impressively wide field. I would estimate the sweet spot to be about 80% of the field of view, but falls off very gently as the field stops are approached. The remaining 20% showed progressively more field curvature that younger eyes can accommodate to some degree, and some mild pincushion distortion near the field edges. Contrast is most excellent, with very good control of glare. Colors are vivid and true to form. Greens and browns are particularly well enhanced, especially as the late February-early March light faded in the evening. An overall light transmission of 90% is very credible in my opinion. I couldn’t detect chromatic aberration in the center of the image. Viewing some denuded tree branches against a uniform, grey sky did throw up a trace of lateral color from about 65% of the way out from the center, becoming a little more pronounced right at the edge of the field. Depth of focus on the GPO Passion ED 8×32 is quite good. Looking across an open field on a bright sunny day, I was able to view objects from about 50 meters all the way to infinity in wonderful, sharp focus, as if you were actually there. Examining the trunk of an old, dead tree trunk some 25 meters away generated vivid three dimensional details of the moss, fungi and wood grain, as though I could reach out my hand and touch it! I believe this very immersive depth perception was particularly vivid owing to the excellent sharpness across the majority of the image, coupled to its very generous field of view (8 angular degrees). Close focus was significantly better than advertised too. I measured it at 1.87 meters; good news if you like to observe insects, flowers, water courses and rocks at close hand. Testing binoculars under the starry heaven is arguably the best way to assess aberrations and to check alignment of the barrels. That’s because it’s easy to get overwhelmed by a daytime vista in all its rich detail, and it can be difficult to judge where off-axis aberrations begin to encroach. Stars and other celestial objects are much simpler animals in comparison, and how they distort as one moves off axis is easier to diagnose. The first thing I did was to check collimation. This was easily achieved by placing the brilliant star Sirius in the center of the field, while the binocular is mounted on a tripod. The Dog Star is close to the meridian after dark on early March evenings, and so is very well placed for testing. The star is focused as finely as possible and then the diopter ring is turned to the end of its travel to create a prominent anulus of light. If the binocular is properly collimated the perfectly focused left barrel will be located on or inside the defocused anulus. If not, you’ve got an alignment problem. Such testing confirmed that the GPO Passion ED 8×32 was very accurately collimated, with the focused star being located just off the center of the anulus. Good job GPO! Centering the magnificent and sprawling Hyades star cluster, now sinking fast into the western sky, showed that all the constituent stars were morphologically well presented in the binocular. Moving the bright, ochre tinted Aldebaran from the center of the field towards the edge revealed that it remained sharp and acceptably well focused across ~80% of the distance to the field stop, bloating moderately in the last 10% of the linear distance to the field. Much of this bloating could be removed by slight refocusing, indicating that the main culprit was mild field curvature. This test showed that the little 8×32 will make a fine star gazing instrument, as I was to discover after my formal testing ended.

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In another test, I observed how well the glorious crescent Moon retained its brightness as it was moved from the center towards the field stop. I detected very little in the way of brightness drop off, indicating that near full-field illumination was retained all the way to the edges of the field. I detected no visible chromatic aberration on axis but did detect a trace of secondary spectrum as it was moved to about 60% of the way to the field stop. And even at the field stops secondary spectrum was still fairly modest. It is also worthwhile tweaking the diopter adjustment under the stars. I often find that adjusting the diopter on a daytime target does not offer the very best correction. Usually, I obtain rough adjustment on a distant signpost, but quite often I find that when I examine the images of bright stars in both barrels, the diopter compensation can be a wee bit off and can be micro-tweaked on a star image.

Differences Between the 8×32 and the 10×32 Models Apart from the obvious differences in the sizes of the field of view served up by the 8× and 10× GPO Passion 32 mm binoculars, two other disparities are noteworthy. Firstly, the diameters of the field lenses on the eyepieces of the 8×32 are significantly larger than the 10×32. The 8× glass has a 21 mm diameter field lens compared with just 18 mm on the 10× glass.

The size on the eye lens is significantly larger in the 8×32 compared with the 10×32

Differences Between the 8×32 and the 10×32 Models

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Intriguingly, I noticed that the larger ocular field lens in the GPO 8×32 ED induces some occasional blackouts (spherical aberration of the exit pupil) when first looking through the binocular, that are all but eliminated by paying more careful attention to obtaining the optimal IPD for my eyes. This is true irrespective of the fact that the 8×32 model has a larger exit pupil (4 mm as opposed to 3.2 mm on the 10×32). Despite its smaller field lens, I rarely, if ever, encountered blackouts with the 10×32. Secondly, there is a noticeable difference in the focus tension in the 10×32 compared with its 8× sibling. The latter has more tension than the former. I have found that this is actually a good thing going forward, as the 10× glass has a shallower depth of focus than the 8×, and so benefits somewhat from a faster focusing mechanism, especially during glassing adventures in wooded areas. Finally, it’s worth mentioning that GPO also produce their Passion ED 8× and 10×42  in the same range of colored chassis. They’re well worth checking out if you’re after high quality optics in a durable magnesium alloy chassis. During the first week of March 2022, we enjoyed some cold but clear blue sky days, followed by dark, frosty nights. I enjoyed some mesmerizing views of a waxing crescent Moon, with its beautiful earthshine illumining the dark face of our natural satellite. But after the Moon set, I was able to enjoy some wonderful views of seasonal deep sky objects, such as the Pleaides, Hyades, the Alpha Persei Association and the Double Cluster. The super-wide and nearly flat field made observing these extended objects particularly pleasant. Fainter open clusters, such as M35 in Gemini, and the trio of Messier open clusters straddling the mid-section of Auriga, were also very easy to sweep up in this small binocular. As the night rolled on, other opportunities were presented to me to observe the Beehive (M44) and Coma Clusters (Melotte 111). The excellent color correction of the GPO Passion ED binocular presents stars in their natural hues, without any color fringing. I particularly enjoyed glassing some showpiece binocular doubles in Leo, especially Zeta, Gamma and Alpha Leonis. This will make an excellent binocular to observe the full glory of the summer and autumn Milky Way later this year. Birders will find the GPO Passion ED 8×32 to be particularly delightful to use also. It’s very wide, sharp, immersive and glare-free field of view, together with its responsive focus wheel, renders it especially versatile in this regard. The superb ergonomic handling of the binocular in my medium sized hands adds yet another pleasant dimension to using this instrument. I feel that its rugged mechanical design and excellent optics will provide first-rate, hassle-free views for many years to come. How can an instrument of this caliber be offered at such an attractive retail price ($360)? I think that’s probably down to the unique cross fertilization of brains behind the company; founded as it was by professionals from across the leading European optics houses, who bring an eclectic mix of ideas to the table. This, together with the fact that their products are quality controlled in Germany before being shipped out to retailers, gives the consumer much greater confidence of obtaining a quality instrument that will stand the test of time. And that 10-year European warranty (or lifetime warranty if you purchase in the USA) ensures that they will take care of your binocular should you hit any snags!

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A High Performance Porro from Opticron As I write these words in March 2023, it’s getting very difficult to source good-­ quality Japanese-made Porro prism binoculars, especially in the smaller, compact sizes. Over the last few decades aggressive marketing has promoted the roof prism binocular with all its bells and whistles, but with ever increasing price tags. That’s the road I largely followed in my exploration of the binocular market, until I decided to check out a number of Porro designs from companies like Nikon and Opticron, who maintained several high-end models worth checking out. As I explained previously, it takes a lot of effort to create a roof prism binocular that can even approach the optical performance of good quality Porro prism models. In this section, I’ll be demonstrating this proof of concept, by putting Opticron’s Japanese-made SR.GA 8×32 binocular through its paces.

The Beautiful Opticron SR.GA 8×32 binocular

Perusing the Opticron UK website, I came across details about the SR.GA 8×32 model. Featuring a whole host of attractive features, including state-of-the art Japanese Porro prim optics, a well-made chassis and rubber armoring, all for an attractive retail price of £200. Incidentally, it’s available in the US for a retail price of about $315, but was discontinued as of May 2022. I contacted a member of the sales team at Opticron, Luton, and they were able to ship me out a unit. I was very excited when the package finally arrived, double boxed, with everything packed away well. What I received was the binocular inside an attractive, black leather case, together with a nice selection of high quality accessories, including a logoed neoprene neck strap, objective and ocular lens covers, a rain guard, a microfiber lens cleaning cloth, instruction manual and that all-important 30 year warranty (in the US it’s supplied with a Premier Plus Limited Lifetime warranty).

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The reader will note that at one time no less than 4 SR.GA models were being offered by Opticron: 8×32, 7×42, 8×42 and 10×42. The larger models appear to be discontinued and I was informed that they only had limited numbers of the 8×32 model available. Opticron state that these were updated versions of their earlier HR models, but I also found a source claiming that the SR.GA 8×32 in particular, has the same optical specification to another model which just pre-dated the HRs, that is, the Dioptron 8×32. The SR.GA is a very finely made instrument. In the hands, it feels very solid, with the rubber armoring helping the user maintain an excellent grip. The oversized focus wheel is covered in fine rubber and is exceptionally fast, moving from close focus to just beyond infinity in less than half a turn (actually about 160 degrees). Some super-fast focusers make it easy to overshoot by accident, moving past the ideal focus position too easily. This is never a problem with the SR.GA 8×32 though; the gearing and tension is just perfect for high speed focusing. There is no backlash or free play either. In short, this is one of the nicest focusers I have had the pleasure of using in a binocular in this size class! The diopter compensation ring is located under the right ocular. It’s adjusted by rotating it slowly clockwise or anti-clockwise. It’s not quite as well tensioned as other high-quality compact Porros like the Nikon E II 8×30, and, as a result, it does tend to wander a wee bit in field use. This can be easily remedied by wrapping a small elastic band round the ring. For me, I just remember my preferred position and make slight adjustments every now and then when required. The eye relief on all these classic, compact Porros is poor, it has to be said. It’s just 13 mm on this model. That’s not an issue for me, as I don’t wear eyeglasses while using binoculars but those who must wear eyeglasses will find viewing the entire field problematic. I checked this by turning down the rubber eyecups. I could not image the outer part of the field while wearing eyeglasses. Just like the Nikon E II, spectacle wearers will benefit from using more contoured glass lenses with high-­ index glass. Just as the thick rubber armoring will help protect the instrument against knocks and light rain, the deeply recessed objective lenses also confer quite a bit of protection against wind-derived dust, rain and stray light. All in, this a very delightful instrument and a real joy to use. My bright light test yielded good results. There were no diffraction spikes and only a few slight internal reflections in evidence, with only a trace of diffused light observed around the light source. Compared with the older Dioptron 8×32, it was a far cleaner result. Later, I turned the binocular on a bright, yellow sodium street lamp and did manage to detect some very weak internal reflections. In this capacity, it was a notch down from the excellent Nikon E II Porro prism binocular, which shall be discussed later in this chapter. Turning to a bright gibbous Moon low in the southeast, I was pleased to see that these internal reflections were quite well subdued. This will be a good instrument to follow the phases of the Moon with, and for observing cityscapes at night. The exit pupils are round and untruncated, with little in the way of light leaks around them.

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Testing under the stars showed the binocular to be very accurately collimated. I detected a modest drop in illumination as a bright gibbous Moon was moved from the center of the field to the extreme edge, but all within design tolerances. The Opticron SR.GA 8×32 serves up a really good image during all daylight conditions. It’s bright, with excellent sharpness across about 70% of its very large field (8.25 angular degrees). The outer 30% of the field shows progressively more field curvature and pincushion distortion, but not to the extent that it is distracting. Contrast is excellent, as is color saturation. I found comparing it to the older Dioptron model to be eye opening (excuse the pun). The latter image was quite yellow and less bright in comparison to the much more neutral colors served up by the SR.GA. This probably indicates that its light transmission curve as a function of visual wavelength is flatter and brighter in comparison with the Dioptron. The other thing that was noticeably improved was glare suppression while looking near a setting Sun. The SR.GA was far superior to the Dioptron in this regard, and the same was true when testing for veiling glare. That said, the SR.GA was not quite as good as the Nikon E II 8×30 in similar, side-by-side tests. Color correction is excellent: I detected none on axis and only a trace when examining high contrast objects, like a telephone pole set against a bright, leaden sky. As I’ve come to expect from a high-quality Porro prism binocular like this, the instrument manifests vivid 3D images of the landscape over short and medium distances. Like the superlative Nikon E II 8×30, there is very much a sense of ‘focus and forget,’ especially when trained on targets beyond about 40 m or so. I measured its close focus- 2.84 m – to be significantly better than the advertised 3.7 m. Just like the Nikon E II, scanning large swathes of landscape with this instrument is supremely comfortable, with no blackouts to mention and no rolling ball effect. As a stargazing binocular, I enjoyed lying out on a recliner in my back garden in the wee small hours of an early May morning, scanning the summer Milky Way through Cygnus. Stars show up as lovely pinpoints of light across most of its expansive field, against a dark sky background. Though not the best instrument for binocular stargazing, it still showed me pretty views of the Coat Hanger asterism in Vulpecula, the great globular cluster M13 in Hercules, and some lovely views of the color contrast binocular double O^1 Cygni. This will make a rather good instrument for enjoying the up-and-coming Perseid meteor shower when truly dark skies return to our shores in early August. It has also presented some lovely, high-contrast images of the crescent Moon and earthshine, as well as tack-sharp images of crater fields and the lunar maria. In summary, the Opticron SR.GA will make an excellent general-purpose instrument. Though it’s not waterproof, it’s most certainly a tough little binocular, and ergonomically is very easy and intuitive to use. I enjoyed many hours using with this instrument, surveying the hills around my home, exploring woods and forests, stretches of river and ponds, and also for scanning trees and bushes for small, passerine birds. It even served me well on a short boat trip out to Ramsey island, Pembrokeshire, Wales, to do a spot of marine birding.

A Wide, Relaxed View from APM

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A Wide, Relaxed View from APM

The APM 6×30. (Image Credit: Paul Wehr)

Germany-based optics firm, APM, recently launched two very stylish Magnesium Series 30  mm Porros in 6× and 8× magnifications with a strong retro look. Paul Wehr, a keen binocular enthusiast based in New York, told me about the 6×30. This little beauty sports a 9.3-degree field of view, has fully multicoated optics and an ED objective lens element to reduce color fringing to a minimum. Light transmission is reportedly of the order of 90%. Central sharpness is excellent, at least as good as the Nikon E II 8×30 (discussed later) and the sweet spot is very large with only very mild field curvature at the edge of the field. Depth of focus is impressive by all accounts, thanks to the 6× magnification and the eye relief is a very decent 18.5 mm. Mechanically, the APM 6×30 is very well endowed. The central focuser moves smoothly and precisely, and the instrument is sealed and nitrogen purged so can be used in all weathers. Weighing only 530 g, you can take this little binocular practically anywhere with you. Best of all, the Magnesium Series 6×30 retails for about $250.

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A Great Performing Compact Binocular from Kowa

The Kowa SV II 8×32. The new green armoring replaces the old black rubber of the first generation SVs

The Japanese optics company Kowa has earned an excellent reputation among sports optics enthusiasts for over three quarters of a century. Today, they offer an exciting range of binoculars and spotting scopes that constantly push the envelope in ergonomic and optical performance. At the time writing, Kowa manufacture an impressive array of binoculars to suit most people’s budget, ranging from tiny, pocket-sized binoculars right up to 56 mm monsters. The SV series, Kowa’s entry level mid-sized binoculars, were first introduced in 2011, and created quite a splash, with many birders and hunters singing high praises for their innovative design and great optical performance. But in January 2020, Kowa introduced their revamped SV II series, which gives the customer a choice of six models in all – just like the original series – an 8×32, 10×32, 8×42, 10×42 and two 50 mm models giving 10× or 12×. I ordered up the 8×32 SV II model for testing an evaluation. I’m also delighted to say that it was a very pleasant surprise! To see why, read on! The binocular arrived inside a padded logoed carry case, which in turn was placed inside a small green box. The instrument has a thick green rubber armoring; very reminiscent of the Leica Trinovid HD 8×32 I tested. The chassis is fashioned from a lightweight but tough polycarbonate substrate and has extra rubber padding around the objective lenses to afford them some extra protection from stray light and the elements. The rubber is beautifully textured and very easy to grip but does attract dust rather easily. The eyecups on the Kowa SV II 8×32 were also a very

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pleasant surprise. They have four positions in all and lock into each position with a reassuring ‘click’ sound. I’m also happy to report that the eyecups don’t collapse unless a sizeable force is applied to them. Eye relief is tight though: I struggled to see the entire field with my eyeglasses on. Fortunately, that isn’t an issue for me as I don’t wear glasses while using binoculars. The focus wheel is covered in soft rubber with tear shaped indentations very much like those used on Kowa’s YF range of compact Porros. I judged its tension to be excellent – very smooth with no free play and backlash when rotated clockwise or anticlockwise. 1.75 revolutions clockwise brings you from closest focus to just beyond infinity. The Kowa SV II 8×32 feels great in the hands as it’s so easy to grip and wrap your hands around. Kowa didn’t skimp on the strap either; it was easy to attach and is nicely padded for comfortable transporting. The exterior lenses are treated to Kowa’s proprietary KR coating to repel water, dirt and oily deposits and helps protect against accidental scratching. There was no cleaning cloth supplied with the instrument. The ocular rain guard is made from standard rubber, but the objective caps are of the cheap plastic variety. To summarize, I love the thoroughly modern design of this binocular, which was very thoughtfully designed to be pushed hard in the great outdoors. I began to test the optics by examining how the instrument handled an intensely bright beam of light from across a room. The results I got were very encouraging. There was very little in the way of internal reflections and ghost images. I did see a weak diffraction spike though, but it was quite subdued compared with other instruments in this price category. There was very little diffused light around the beam, indicating the glass used was of very good quality and of high homogeneity. Later, after dark, I turned the Kowa SV II 8×32 on a bright sodium streetlamp and, as expected, I got a great result; no ghost images and only the merest trace of a faint diffraction spike. In another test I examined the light emanating from the exit pupils. The results were excellent, with nice dark areas around the perfectly circular pupils. So far, so very good! The view through the Kowa SV II is excellent; very bright, sharp and with impressive contrast. The excellent tension on the focus wheel brings the images to a very precise, razor-sharp focus, with absolutely no ambiguity. Colors are vibrant and true to life, presenting with an overall neutral cast to my eyes. The sweet spot is very large, with only the extreme edges of the field showing any significant distortion. This I was able to ascertain by star testing more fully at night. Centering the bright star Vega in the field of view, I was able to monitor how the image changed as it was moved off axis towards the field stops. I was delighted to see that even at the extreme edges, there was only very minor distortion mostly attributed to very mild field curvature. To be honest, I had expected it to fare worse in this regard as the specs of this binocular – 7.8-degree field, 15.5 mm eye relief etc. – are found on quite a few other models, such as the Svbony SV 202 8×32 and the Celestron Trailseeker 8×32, for example, each of which had quite blurry images near the field stops, as my notes showed. This Kowa SV II turned out to be in a completely different league in this regard, with a much flatter outer field.

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Glare suppression was also in a completely different league to the aforementioned models too. The excellent coatings and baffling on these Kowa SV IIs made all the difference in aggressively suppressing both general and veiling glare after extensive field testing. Close focus was measured to be just 1.68 m, considerably better than the quoted 2 m stated in the accompanying user manual. Blackouts – caused by spherical aberration of the exit pupil  – were pretty much nonexistent. Overall, I found the views extremely relaxing and engaging, a sure indicator of an optically excellent instrument. But how, you may legitimately ask, can you get such high quality at such a low cost? The answer may lie with the focal lengths of the objectives; by making the focal length longer all aberrations are reduced. This increases the physical size of the instrument, but I’d say it’s a fair trade off to get those superior images! Though the field of view is fine and wide, one gets the impression that it’s wider than it really is owing to the well corrected outer field. Chromatic aberration is very well controlled despite its non-ED billing. I could detect the merest trace of it in the center of the field on the highest contrast daytime targets though, and an average level of lateral color as one moves away from the center to the periphery of the field of view. There is a modest amount of illumination drop off as targets are moved to the edge of the field. This was easily seen by centering the Pleiades in the binocular field and then moving the celebrated asterism to the field stops. In conclusion, the Kowa SV II 8×32 is an excellent instrument for birdwatching, nature studies and even for enjoying the showpiece objects of the night sky. For its modest retail price ($259), it sure punches well above its weight. The Kowa SV IIs are also available in larger 42 mm and 50 mm formats.

 n Excellent But Recently Dis-Continued Compact Roof A Binocular from Celestron Celestron is a name that is more commonly known among amateur astronomers than birders, but together with Meade, they have recently waded into the highly competitive sports optics market, offering both advanced Porro and roof prism models at prices that won’t break the bank. I hooked up with Philip Grimsey, based in Hitchin, Hertfordshire, UK, a keen birder and amateur astronomer, who, I discovered shared many of my personal tastes in binoculars and telescopes. Philip relayed an interesting story to me regarding his experiences with a Celestron Granite 7×33 roof prism binocular, now recently discontinued but still available from some retailers and on the second-hand market:

An Excellent But Recently Dis-Continued Compact Roof Binocular from Celestron

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The Celestron Granite 7×33 open Bridge binocular. (Image Credit: Phil Grimsey)

“I purchased this glass in April 2018 and was attracted by the substantial reduction in the retail selling price which was originally in excess of £400. I paid just £169 from Carmarthen Cameras and as it has turned out it was money well spent. The binocular was a revelation. At the time I was the proud owner of the last version of the Zeiss 7×42 BGAT which was phase coated and sharper than the earlier versions of that glass. I wanted to see what the Celestron binocular was like against the Zeiss. Hardly a fair comparison I hear you say but a quick look at the Granite’s specification tempted me in to buying the Chinese made glass. In brief the main and important details for me were… A field of view of 9.1 degrees equating to 159 meters at 1000 meters (9.1 angular degrees). Multi Coated Optics including a phase coating ED Glass Long eye relief of 15 mm Close Focus of 2 meters Open bridge design Weight only 601 g Waterproof and fog proof. In practice the glass is very sharp, at least as good as the Zeiss with nice color correction. Perhaps a slightly cool image but not unpleasantly so and with very little distortion which is there if one’s eyes stray to the outside of the image. This is not a problem for me as I am generally looking in the middle of the picture. That picture

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is very steady with the 7× magnification (my favorite for a binocular), it is overall a very pleasing image being nice and bright as well. Only having 33 mm objectives the binocular is very compact having a height of only 140 mm…nice and compact. It performs well enough in poor light although of course the Zeiss will always win here. Focusing is excellent, very smooth and quick enough.

The beautiful anti-reflection coatings on the Celestron Granite 7×33. (Image Credit: Phil Grimsey)

It came with a full package of accessories namely, a neck strap, harness strap, objective lens caps and Eyepiece rain guard, carrying case, lens cloth and instruction manual. In-short a very capable binocular although the objective lens covers are a bit of a nuisance dangling down at the front. They can be detached, however. I continue to get a lot of pleasure from the glass. It may not be as well made as the Zeiss and I doubt it will last as long. Used with care though, I am sure it will give many years of good service. As mentioned earlier a revelation at the price. If you see a used example for sale in good condition, snap it up, it will not disappoint.”

A Super Fine Compact Binocular from Leica

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A High-Performance Compact from Opticron

The Opticron Traveller BGA ED 8×32. (Image Credit: Optricron)

Fancy a really great, light weight binocular for exploring the great outdoors? Look no further than the Opticron Traveller BGA 8×32 ED.  Built around a low density but high strength polycarbonate chassis, the BGA Traveller ED tips the scales at 450 g and is packed full of high-end optical features that let you enjoy a great view. The binocular features dielectrically coated and phase corrected roof prisms, Opticron’s proprietary multicoating and ED glass elements to cut color fringing to a minimum. The field of view is a very impressive 8.2 degrees for the 8× model and 6.5 degrees for the higher powered 10× version. The BGA Traveller EDs have a very nicely made twist-up eyecups offering four positions and the 19 mm eyepiece makes them easy to use with eyeglasses. The great field of view bring a lot of nature in front of your eyes. The large 22 mm ocular lenses make it easy to center your eyes in and their soft rubber cladding make them very comfortable to use for hours on end. The large centrally placed focus wheel is nicely engineered and moves smoothly using one finger for precise focusing on the fly. The Opticron Traveller BGA ED compact binoculars are backed by the company’s 30-year warranty for peace of mind and retail for $350.

A Super Fine Compact Binocular from Leica The Trinovid line of binoculars by Leica has long been considered the company’s ‘heritage’ brand. First produced in the late 1950s, the Trinovids were so named because of the three features – or Tri Novitäten in the German tongue – which combine state-of-the-art optics, true internal focusing and excellent ergonomics in one tidy package. If you think the latest incarnation from Swarovski  – the NL

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Pure’s – have a wide field of view of at 159 m@1000 m, it pays to remember that Leica was churning out Trinovids with much larger true fields – up to 170 m@1000 m by the mid-1960s. If that isn’t prestigious enough, a Leica Trinovid – really a highly specialized 10×40 monocular nicknamed the “Eye of Apollo” – accompanied the US astronauts on their epochal sojourn to the lunar surface in the summer of 1969. The Trinovid remained Leica’s flagship binocular until the introduction of their Ultravid line in the mid noughties but were continued as a lower cost alternative until Leica ceased production of the Trinovids altogether in 2015, much to the chagrin of many Leica fans. So that was the end of a line of binoculars that served the outdoor enthusiast perfectly for well over half a century right? Thankfully, no! In 2016, the company announced a new line of Trinovids, revamped with an ‘HD’ moniker. As usual, the new Trinovid HDs  – all made in Leica’s factory in Portugal – were first launched in the perennially popular 8× and 10×42 incarnations, but a year later Leica added two smaller glasses to the same family – the 8× and 10×32. This section will take a close look at the 8×32 model. Leica specifically marketed the new Trinovid HD line as “entry-level premium class,” whatever that means.

The Leica Trinovid HD 8×32

The instrument came in the standard padded grey and green Leica box, complete with neoprene carry case, a lens cloth, padded neck strap with the Leica logo, rain guard, tethered objective lens covers, instruction manual, test certificate and warranty card. I was immediately struck by the beautiful, solid build quality of the instrument, with its magnesium chassis and thick, flat black rubber armoring. The red Leica logo made for a nice aesthetic touch embedded at the end of the right barrel of the instrument. Built like a proverbial tank, the large central focus wheel moved with silky smoothness, taking just over two full revolutions from one extreme of its travel to the other. This extra-long focus travel is unusual in a binocular of

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these specifications but is required for the instrument’s amazing close focusing distance of under 1 meter – the closest I have personally encountered by quite a considerable margin, with the exception of the marvelous Pentax Papilio II 6.5×21 discussed in the previous chapter, with its unrivalled 0.5 meter minimum focus. After a few times using the instrument, I did detect a very slight amount of play in the focuser, which was a wee bit distracting but something I could live with. I was very much looking forward to examining the eye cups on this Leica, which turned out to be every bit as good as I had hoped! They are beautifully engineered with five positions from fully extended to fully retracted, and all locked into their respective positions with a loud and reassuring ‘click’ sound. Supremely comfortable, they are ‘cushioned’ in a lovely soft rubber that sanctions prolonged glassing in the field. They remain in place with a rigidity (read rock solid) that I had come to expect from this company owing to my previous pleasant experiences with its smaller sibling – the Leica Trinovid BCA 8×20 pocket glass. Sporting a very generous eye relief of 17  mm, this is one binocular that eye glass wearers will never struggle to see the full field with! That’s good news going forward, as I don’t know if I will eventually have to observe with my eyeglasses on all the time. The eye cups are also removable should I wish to give them a thorough clean. The rain guard is very snugly fitting – indeed it takes a bit of effort to prize it off if you’re in a hurry. But I find that it affords that little bit more protection to the eye pieces during rough handling, especially if dust, dirt and sand are prevalent. This is the case irrespective of whether or not the eye cups are extended or fully retracted. Same goes for the objective lens covers too. Unlike most others which are far too loose, these stay on snugly helping to protect the instrument. Unlike the older Trinovids and the current Ultravid models, the new Trinovid HDs have their diopter setting placed under the right ocular lens, as is common with the vast majority of binoculars you’re likely to come across. It has a prominent red line which one can use to mark the optimal setting for your right eye but is not lockable unlike that found on the Ultravid models. Many of the reviewers cited above view this as a retrograde step, but personally, I have always felt that having a lockable diopter is a bit of a gimmick; more an over-engineered ‘gee whizz’ solution than anything else and not really worth the extra cost incurred in acquiring a model with one installed. Other folk may have different opinions on this and that’s OK. But there are other practical reasons why I prefer to have a diopter setting that can be adjusted on the fly. Knowing my own physiology, I have come to learn that my eyesight can change ever so slightly if I glass in the early morning after resting for many hours, or after staring at a computer screen for a long period of time. I also notice small changes if I’m tired. And all of these states often have me reaching for the diopter ring to micro-adjust the focus in my right eye during critical glassing moments when I require the very finest images the binocular is likely to provide. The adjustments, though very slight, are nonetheless real, and so having a well-­ made but conventional diopter ring that I don’t have to adjust by pulling on the focus wheel and fiddling with a dial is actually a distinct advantage in my books. My first look through the Trinovid greatly impressed me; I was immediately taken by its bright, sharp and color-rich images of the creation. Indeed, that first

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look convinced me that I had an excellent optic in my hands, as I will elaborate on shortly. So, without further ado, let’s have a look at the results my tests revealed about this binocular in comparison to the other models cited above. The instrument proved excellent at suppressing internal reflections as judged by looking at a bright white light in my living room and also after dark, observing a bright yellow sodium street light. The Leica Trinovid HD will make an excellent binocular to study nighttime scenes such as cityscapes from a lofty vantage, a bright full Moon, or a distant harbor lit up at night. All binoculars, no matter how well made, suffer from some degree of veiling glare while glassing under an open sky in broad daylight. I am happy to report that the Leica Trinovid HD 8×32 aggressively minimized this effect. Kudos to Leica for addressing this niggling and pervasive problem! Glassing some late flowering Cosmos flowers in my back garden in bright sunlight was enough to show off the quality of the images in this new Leica glass. The glass is supremely sharp across the vast majority of the field, with only a little peripheral softness near the field stop. Like all the roof prism binoculars I have had the pleasure of using, lateral (horizontal) field correction is noticeably better than when the same image is examined by moving a target from the bottom to the top of the field (vertical panning). This is not unique to the Leica Trinovid HD though: virtually all other binoculars I’ve tested display this asymmetry. The Leica image has a real sparkle to it with noticeably better contrast than many other mid-priced binoculars. Reds and yellows are especially enhanced to my eyes. It was almost as if someone had peeled away a thin veil allowing my eyes to see those last fine details that had remained more elusive in other instruments. Glassing the top of a telephone pole against a bright overcast sky revealed some color fringing in the Leica Trinovid HD however. I found that by moving my eyes around the exit pupils could make much of this fringing disappear. According to Leica USA’s Jeff Bouton, the new Trinovid HDs do indeed employ some kind of ED glass but they are not as well corrected in this capacity in comparison to their more expensive Ultravid line. It just goes to show, once again, that a binocular need not exhibit overly aggressive control of secondary spectrum to deliver a gob-smackingly good image. To my mind, the Leica Trinovid HDs offer a very convincing ‘proof of concept’ in this regard. The Leica Trinovid HD boasts an excellent transmittivity of 90%, placing it just a few percentage points behind the very best binoculars currently available. But how would it fare against the much more economically priced 8×32 Trailseeker binocular in low light conditions, such as those experienced at dawn or dusk? Remembering that this glass sports fully multi-coated optics, phase corrected prisms with high reflectivity dielectric coatings but no ED glass, I performed some tests on tree branches some 50 yards distant after the Sun had set in early August skies. The results were not surprising to me, given what I had already learned from a number of other tests carried out earlier in the year; there was very little difference in perceived image brightness between all the instruments. What this tells me is that light transmission is very efficient in these mid-tier binoculars. I would be confident enough to bet that they transmit 85%+of the light they collect and that’s very good

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news for the budget conscious consumer. How times have changed from only a short few years ago! What is more, the claim that ED glass results in brighter images was not really in evidence in these tests either. The Trinovid HD 8×32 has an excellent depth of field. Anything beyond about 50 yards remains in good focus, only requiring a slight tweak of the focus wheel to obtain ultimate sharpness. But it is its remarkable close focus  – just 0.95  m as I measured it – that really distinguishes it from its competitors including the company’s more expensive Ultravid and Noctivid lines. Viewing objects at close focus – rocks, flowers, insects – has brought many joyful experiences, although I have to switch to ‘monocular mode’ to get the most comfortable views at these short distances. I estimated the field of view under the stars, where I was able to hold Alkaid and Mizar & Alcor in the Big Dipper asterism in the same field of view with a little bit of room to spare. Since these stars are ~6.7 angular degrees apart, I felt the quoted 7.1 degree field was quite accurate. I realize that many binocular enthusiasts will be a little alarmed by the smaller field of view offered up by the Trinovid HD. Most 8×32 models have fields approaching 8 angular degrees or even a little higher. I absolutely love the wonderfula, sharp field stops on the Trinovid and the way it frames each binocular scene I wish to image. I also understand from past experiences with instruments like the Nikon Prostaff 7s 8×30, which has an excellent 6.5 degree field, that optical engineers can deliver better edge to edge sharpness by cutting down the field of view. I think the folk at Leica are fully aware of this trick, opting for bigger sweet spots within a smaller field of view, rather than a larger, more conservative field of view but with the loss of critical definition as one moves from the center to the edge of the field. Truth be told, a seven degree field is more than ample for virtually every scenario you’re likely to find yourself in, and in field use I never get the feeling that the image is ‘restricted’ or ‘tunnelled.’ The Leica Trinovid HD has special coatings applied to the outer lenses which repel dirt, oil and water. Though some Leica-run websites give the impression that this coating is their patented AquaDura, I felt it best to contact the UK Leica Sports Optics team directly for clarification on this matter, and here is how they replied: The lenses of all Leica Trinovid binoculars feature an extremely effective, water-resistant and dirt-repellent coating. It is a similar style of hydrophobic coating in that it doesn’t allow water to pool on the lens should you be using them in the rain and it also makes cleaning them easier as fingerprints and dirt along with water can’t cling to the surface. The actual “Aqua Dura” coatings are reserved for our Ultravid HD+and Noctivid ranges only.

Fortunately, this is easy to test at home. I set up the Celestron Trailseeker 8×32 (which does not have such coatings) alongside the Trinovid HD glass. Both these instruments have the same ocular lens size, so I breathed heavily on them, creating a ‘fog.’ Next, I watched both to see which one dispersed that fog more quickly. The easy winner was the Leica. I would estimate that it takes about three times longer to disperse on the uncoated Celestron. This will prove to be very useful in the colder and damper months of the year, where exterior fogging is a common though inadvertent problem.

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Though you can fruitfully engage with the night sky with any binocular, large or small, I find a 30 mm aperture about the minimum that will yield views that will keep you engaged for long periods of time. And going from 30 to 32 mm results in a noticeable (~14%) increase in light gathering power. With the light from the city of Glasgow some 25 miles to the south having diminished during the lockdowns, the sky is noticeably darker to my eyes and more majestic with it. The Leica Trinovid HD 8×32 was my instrument of choice to re-explore a truly dark sky after the summer twilight had come and gone. In mid-August, with no Moon in the sky, I set up a comfortable recliner in my back garden, and lying on my back, I explored the starry heaven down to perhaps the 9th magnitude of glory. The stars appear as beautiful, tiny pinpoints and their colors true and rich. I’ve even watched falling stars streak across the field during the Perseid meteor shower in the second week of August, and even witnessed a few brilliant fireballs with this wonderful, small glass. To me the stars are like old friends that come and go as the seasons change and I have enjoyed observing all manner of deep sky objects with this little instrument – the comely Pleiads and the Hyades in the wee small hours of the morning, the Coathanger asterism, the Engagement Ring around Polaris, the majestic Double Cluster and brilliant stellar associations such as Melotte 20 in Perseus. Later in the night, Auriga begins to dominate the eastern sky and all three of its Messier open clusters can be framed within the binocular field. Scanning the Milky Way through Cygnus, I usually pause to soak up the especially rich star fields around Sadr and Deneb, before panning onwards into Cassiopeia further east. I have also enjoyed gazing at the Moon growing ever brighter as the days of August proceeded, its size appearing larger owing to its proximity to the horizon. The Leica binocular serves up tack sharp images of the lunar regolith, set against a jet-black sky and remaining pleasingly coherent even at the edge of the field. Placing a bright Gibbous Moon just outside the field stop shows that this binocular is superior to the other models in suppressing stray, off-axis light. And when the rain clouds move in from off the Atlantic, racing across the Moon’s silvery countenance, they create painfully beautiful light shows that are rich in color. In short the Leica is a wonderful companion by day or by night. I have even made some makeshift white light solar filters to fit over the instrument’s objective lenses to keep an eye on the Sun. Just a half mile from my home is Culcreuch Pond, where I have spent a few minutes on most dry days glassing a pair of Mute Swans and their new family of six cygnets. I have watched them grow from tiny hatchlings to strong and healthy juveniles. The bright, dry spring and warm, wet summer of 2021 had generated plenty of pond vegetation for them to thrive on. On many days, the adults see me observing them from the banks and begin to swim their way towards me, the cygnets following their parents gracefully in a wonderful flotilla. And they get really close too; often within a few meters of where I’m standing. The youngsters make loud whistle sounds as they approach in search of an easy meal, but I’ve always resisted feeding them. I guess other folk do throw them food, explaining why they cross the pond to see me. To the casual onlooker, they all appear more or less identical, but I have

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come to know them so well that I can identify unique markers on their body that helps me to distinguish them. The pond is also a good place to observe all manner of duck, Gooseanders, Coots and even the odd Grey Heron lurking in the reedy shallows. Unlike the swans, Herons are far leerier of humans and getting closer than a few tens of meters has proven all but impossible for me. Still, the Leica glass allows me to make up for this distancing and I have observed these magnificent birds as they patiently patrol the shores for approaching fish. Looking eastward beyond the pond, the hills soar 1000 feet or so above the valley and I can often observe majestic raptors – mostly Buzzards but also the odd Peregrine Falcon gliding effortlessly on the warm summer thermals. Much of the lower lying parts of the hills are covered by deciduous trees and bracken which change their colors as the seasons progress. I can’t think of a better binocular to explore the radiant colors of autumn than the Leica Trinovid HD 8×32.

A fine outdoor glass

I commend the Leica Trinovid HD 8×32 to the enthusiastic naturalist, birder or casual star gazer. It does exactly what it says on the tin and its robust  – indeed slightly overbuilt – construction will appeal to those who value performance over bling. It has a classical look and feel about it that is as good to look through as it is to look at. It is durable, waterproof to 4 meters depth, and can be relied upon in all weathers. It yields wonderful, bright and tack sharp images of the natural world that will delight anyone who looks through it. Is it perfect? No, but you can easily forgive its shortcomings!

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From Trinovid to Ultravid HD Plus

The Leica Ultravid HD Plus 8×32. (Image Credit: Paul Wehr)

If you’ve been delighted by the images the Trinovid HD serves up, what then can we expect from the 32 mm Ultravid HD Plus models from Leica? Widely considered to be one of the most ornate binoculars in the world, the Ultravid HD Plus exudes quality, with a treasure trove of high technology packed into a tiny body weighing just 535 g. With the exception of the Ultravid pocket binoculars, Leica employs specially formulated SCHOTT HT glass in their Ultravid line, which increases light transmission especially in the blue-violet light band, improving color fidelity, and enhancing low-light performance. Leica has also engineered scratch- and abrasion-resistant High Durable Coating (HDC) and hydrophobic AquaDura coating on the outer lenses which protect optical surfaces which causes water and oil to bead off for easier cleaning and clearer vision. The roof prisms in the Ultravid HD Plus 8× and 10×32 feature P40 phase correction and proprietary High Lux System (HLS) coatings. As you’d expect from a top-tier product from Leica, the Ultravids have uncompromising construction details. To reduce user fatigue during long glassing sessions, the chassis is made of a lightweight yet durable magnesium alloy, with a high-tensile titanium center hinge axle. The optical tubes are nitrogen filled for fogproof performance and sealed to make the binoculars submersible to 16  feet. Protective rubber armoring, provide a comfortable slip-resistant grip. To top it all off, a lubrication-free focus system provides fast and precise focusing, with

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PETP-Discs to provide smooth movement throughout the broad operating temperature range. The original 32 mm Ultravids were first brought to market back in December 2003, but within just a few short years, the Ultravid was revamped, first with the launch of the Ultravid HD and finally, in a second revamp, the Ultravid HD Plus in 2007. If you were to examine these three versions of the Ultravid externally, you’d hardly notice much difference. Optically however there have been incremental improvements in coatings and overall light transmission which is of the order of 91% across most of the visual spectrum. So how does the little Leica Ultravid HD deliver optically? Owners report excellent sharpness and very good brightness and contrast. At 7.7 degrees the view is decently wide, but certainly not exceptional by modern standards. An 8×32 unit I tested had a close focus of just 2.1 m, no better than most 8×32 roofs on sale today. What is immediately obvious however, comparing the Ultravid HD Plus to the Trinovid HDs is the color correction, with the former being noticeably better on a variety of high-contrast targets. Colors are beautifully presented in this little binocular, typical of Leica. Though the sweet spot is generously large, it’s not sharp to the edges, with just a little peripheral softness at the field stops that most users can comfortably ignore. Glare is very well suppressed but I did pick up some minor veiling glare issues while imaging the topmost boughs of some conifer trees set against a uniformly grey sky. In addition, I did detect some minor lateral color while glassing through several layers of branches on a dull autumnal afternoon. Ergonomically though, there is very little to fault. The focus wheel is much superior to that found on the Trinovid HD, with no free play or backlash. One and a quarter turns clockwise brings from closest focus to a little bit beyond infinity. The Ultravid HD Plus has a locking diopter mechanism built into to the focuser. Pull it out to expose the dial, set it to your desired setting before popping it back in again. The twist up eye cups are a real work of art, with several intermediate positions between fully extended and fully retracted. If anything, they felt a bit on the stiff side on my test unit, but better this way than to be overly loose. The eye relief of 13.3 mm is a bit restrictive to those who wear eyeglasses, and in some cases, it can be a real deal breaker. Other folk have commented that the binocular is a bit too small to fit in larger hands. That wasn’t the case with yours truly. They were the perfect size for my medium-sized hands. If you want higher power, why not consider the 10×32? It has a smaller field of view, as expected, but is still generous at 6.7 degrees so still quite wide for a 10× glass. In summary the Ultravid HD Plus 8×32 was a real pleasure to test drive. It’s one of those instruments that looks as good to look at as through. As you might expect, these don’t come cheap. Expect to pay just over $2000 for the privilege of owning one.

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A Stellar Performer from Nikon

The Nikon Monarch HG 8×30 package

If you think the Nikon M7 8×30 is good, you’ll likely be bowled off your feet by Nikon’s premium line of Monarch HG binoculars made in Japan. The Nikon Monarch HG 8×30 I tested arrived in a rather plain looking brown box. Inside, the binocular was nicely housed inside a high-quality zipper-closed clamshell case. Everything was packed away nicely, and I was surprised to see that Nikon included two different kinds of objective covers. The first has caps that can be firmly pressed into the objective. The other option is to go without them. In this case, Nikon provide the user with simple rubber covers that protect the ends of the barrels but do not include the tethered ends. Since I’m no fan of tethered caps, I elected to replace them with the sleek rubber covers. The binocular itself is very nicely finished in a leather-like textured rubber that is quite reminiscent of the BL offerings from Leica. The strong Magnesium alloy body provides light weight (just 450 g) but enough mechanical strength to meet the tough demands of outdoor work, yet I was left feeling that the armoring was a bit too meagre compared with the thicker rubber offerings found on the very popular Monarch 7 line. I began to wonder just how durable this covering would be going forward, especially while negotiating thick brush and brambles. Personally, I would have sacrificed some of the obvious aesthetic appeal of this armoring in favor of something a little bit more practical and bulkier.

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The right eye diopter is very nicely engineered. To adjust it, simply push it up, rotate to the desired position and push it back down to lock it. Unlike less expensive models which possess a similar kind of lockable diopter, Nikon’s solution is very firm. I never experienced a situation where it popped up by accident. The focus wheel is a work of art. Taking just over one revolution to go from one end of its travel to the other, it is silky smooth and completely backlash free, enabling one to easily use just a single finger to execute precise focus. Neat! While there are no thumb indents on the underside of the binocular, I found I never really desired them. The longish barrels are easy to get my medium sized hands around and the instrument feels solid and stable to man handle. The stiff, single bridge design works perfectly well with a binocular of this size too, and I was able to engage with it using one hand without any difficulty, thanks to the long barrels. Having said that, I’m not a fan of glassing this way, as two hands are always more stable than one! The eye cups are properly machined metal, with a soft rubber overcoat. They have three positions and lock firmly in place. That said, I have seen similar quality eyecups on much more economically priced binoculars, such that I didn’t consider those of the Monarch HG to be exceptional in any way. For example, I felt they were similar in quality to the Celestron Trailseeker 8×32 I reviewed some time ago. With an eye relief of 16.2 mm, I could image the entire field without glasses, but couldn’t see all the way to the field stops with my eyeglasses on, with the cups fully retracted. Collimation was spot on, as judged by examining the images of a far distant vista in both barrels. Inspecting the exit pupils, I was less than impressed with the amount of light leaks around the eye box though, as I expected a little better attention to these details in a binocular marketed as ‘premium.’ Performing my simple iphone torch test, I directed an intense beam of white light into the binocular and examined the image. I was disappointed to see a fairly pronounced diffraction spike although internal reflections were very well controlled, with no sign of diffused light around the light source. The same spike was present when I turned the binocular on a bright sodium streetlight after dark. Right from the get-go, I was extremely impressed with the brightness and sharpness of the image of the Monarch HG 8×30 in bright sunlight and its enormous field of view (8.3 degrees checked on the stars). The image sparkled with high resolution details on everything from flowers, tree trunks and distant hills. The image was unusually immersive. The image remained impressively sharp across the vast majority of the field thanks to the built-in field flattening technology, with only a minor amount of distortion seen at the field edge. Looking through many layers of fresh mature Sycamore leaves under a forest canopy against a bright overcast sky, revealed virtually no chromatic aberration. Only at the extreme edges of the huge field of the HG did I detect a trace. Glare was exceptionally well controlled on this unit and that was also the case for veiling glare. This is best tested by looking at some under growth with the Sun immediately above it. Here too, the Monarch HG 8×30 bested my Series 5 control – but it wasn’t like a night and day difference. But despite scoring very high marks optically in many departments, the little Monarch HG 8×30 was not without its issues. The most immediate problem I

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encountered was blackouts, that is, spherical aberration of the exit pupils. I found it very annoying. Indeed, it was not only present while panning with the binocular, but it also showed up quite often as I moved my eye around the enormous field while glassing a fixed target. And while one can learn to minimize these blackouts by paying more attention to proper eye placement, I could never really ‘make it go away,’ as it were. Furthermore, the effect was noted by my wife, as well as by several of my students. Looking through my notes on the Leica Trinovid HD 8×32, I also recorded some blackouts, but they were few and far between in comparison to this Nikon binocular. Nor was this entirely caused by the small exit pupil (3.75 mm), as my little Leica Ultravid 8×20, with its smaller exit pupil of 2.5 mm, is virtually devoid of this problem. I concluded that these pronounced blackouts must have something to do with the special, wide-angle eyepiece design of the Monarch HG. Indeed, the same blackouts were also mentioned by a reviewer using a 10×42 Nikon Monarch HG. In addition, I never encountered these blackouts through a Nikon Prostaff 7s 8×30, which, despite its identical magnification, objective diameter and exit pupil size to the HG, has a simpler eyepiece design and smaller field of view. Less serious was the observed rolling ball, a consequence of artificially flattening the field. It was quite apparent while panning the edge of a forest at a distance and gave me somewhat of a queasy feeling. That said, I’m confident I could unlearn this effect with more sustained use. Close focus of the Nikon Monarch HG 8×30 is very good. While advertised at 2 m, I measured a significantly closer focus of 1.81 m. Most targets from 20 feet away all the way out to infinity snap to focus merely by moving the focus wheel through about one quarter of a turn of the wheel. Because the focuser is so soft and smooth, I found this activity to be particularly enjoyable. It really is quite impressive! The image through the HG is impressively bright, with good enough transmission to allow one to continue to glass well into twilight, but ultimately proving inferior to a decent 8×42 in similar low light conditions. Nikon claims a light transmission of 92%, but two spectrophotometric measures on the 8×30 and 10×42 showed slightly lower values of 90.1% and 88.3%, respectively. That said, the light curves look almost identical and show a nice, flat profile over the most important visual wavelengths, peaking in the red. The 8×30 format is about the minimum aperture required to really enjoy the night sky. Smaller binoculars are all well and good for the Moon and some of the brightest deep sky objects, but you go a whole lot deeper moving from 20–25 mm up to 30 mm. The Moon looks very sharp, bright and color free through the Nikon Monarch HG 8×30, but I did notice a trace of the 4 diffraction spikes emanating from the Moon during waning gibbous under good, transparent conditions. Testing on a rich star field like the Alpha Persei Association afforded a good opportunity to test for field flatness/curvature. Canvassing the help of a former student of mine and keen amateur astronomer, we noted that the field is not perfectly flat to the field stops in the Nikon Monarch HG. Stars remained very tight out to about 75% of the field, with distortion increasing rapidly in the last 25% of the field. That said, in most situations, the stars remained acceptably sharp over the entire field, so should be an enjoyable companion under the starry heaven.

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Moving a last quarter Moon from the center to the edge of the field of the HG did reveal a small but significant darkening of the maria which provides strong visual evidence for a drop off in illumination in the outer 20% of the field. I found it very difficult to discern these changes during tests conducted in broad daylight.

A stylish companion in the great outdoors

For some folk, the Nikon Monarch HG might well be a birder’s dream binocular, with its very sharp, contrast-rich and extremely wide and flat field of view. For me though, the blackouts were a major issue which would make me somewhat leery of paying the relatively steep retail price for these binoculars. This concern isn’t just confined to the Nikon Monarch HG though, as another reviewer mentioned how the same phenomenon completely put off his daughter while testing the Zeiss Victory SF 10×32, so any potential buyers will be strongly advised to try them out before buying. What’s more, the small size of the Nikon Monarch HG 8×30 may not suit those who have large hands. In addition, the rolling ball effect, while mild in this binocular, may deter others in favor of models that do not have field flattening technology. In the end, the decision lies with you! One final thing about the rubber substrate used to cover the focus wheel of the Monarch HG binoculars. One very keen birder reported that after only a year of heavy use of her 8×30, the rubber covering was worn down to a thread. I think reports like this need to be taken seriously by Nikon. That shouldn’t happen in such an expensive binocular as this!

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Top Performers from Zeiss Zeiss, of course, is no stranger to the growing sports optics industry and accordingly has developed some amazing compact binoculars for the discerning outdoor enthusiast. Their Chinese-made entry-level Terra 8×32 ED has garnered a good reputation with birdwatchers. We’ve already covered quite a bit of ground on the Terra line in my chapter discussing pocket binoculars, so a lot of what was covered there also applies to the larger Terra binoculars. Like the smaller Terra Pocket model showcased in Chap. 1, the 8×32 ED models have a tough, fiberglass reinforced polycarbonate chassis with excellent handling. Its twist eye cups stay in place rigidly and provide a very decent eye relief of 16.5 mm. The Schott ED glass element in their objectives deliver very sharp, high-contrast images all in a very manageable 510 g package. Zeiss promise a total light transmission of 88% on all Terra ED models, ensuring excellent brightness, even during dull winter days or at dusk or dawn. Zeiss also added a highly effective water repelling coating to the outer lenses and filled the interior with dry nitrogen gas to render it waterproof to 1 m depth. The model I tested had an excellent close focus of 1.5 m, slightly better than advertised and the wide field of view (7.6 degrees) which provides a nice, big, sweet spot that gradually blurs as the field stops are approached. Its higher power sibling, the 10×32 Terra has a field of view of 6.3 degrees. Unlike their more expensive models, the Zeiss Terra ED 8×32 even comes in a variety of chassis colors: black, grey and green. These high-quality compacts retail for about $450. If the economically priced Zeiss Terra ED model doesn’t float your boat, why not step up to the Zeiss Conquest 8×32 HD? Made in Germany, the Conquest delivers even higher light transmission (90%), an even wider field of view (8 degrees) and guaranteed waterproofing to 4 meters depth. But all of this optical excellence comes at a price, both in terms of retail cost (its twice the price of the Terra ED) and carrying weight (630 g). Many novices find it hard to distinguish the images in the Terra ED and Conquest HD, but careful tests involving central sharpness, image contrast, low light performance and glare suppression, will see the latter emerge as the clear winner.

Top Performers from Zeiss

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The Zeiss Conquest 8×32. (Image Credit: John Magera)

The Zeiss Conquest HD 8×32 is a highly regarded binocular and its optical quality is often praised by its owners. The binocular provides a clear and sharp image, even in low light conditions. The colors are true to life and don’t appear washed out or over-saturated, providing good depth perception, allowing for a more immersive viewing experience. The images garnered by the Zeiss Conquest HD 8×32 have excellent contrast, making it easier to distinguish details in dim lighting. The wide field of view allows for a greater range of vision and easier tracking of moving objects. The Conquest is also a good step up in comfortable eye relief, making it suitable for extended use. Overall, the Zeiss Conquest HD 8×32 is well-regarded for its optical quality and is often recommended for birdwatching, wildlife observation, and other outdoor activities. The warranty on all Terra ED models is 2 years, but the better-quality control of the HD series comes with a 10-year warranty. While for most users, the Zeiss Conquest HD will provide all the pleasurable viewing experiences one could want in a modern, high-performance roof prism binocular, some demand the absolute best optics and ergonomics money can buy; enter the Zeiss Victory SF 8×32.

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Zeiss Victory SF. (Image Credit: Philip Grimsey)

The first Victory models appeared back in 2014 to great international applause, but the world had to wait a further six years before Zeiss finally launched what they claim as the finest compact roof prism binocular money can buy. Launched in 2020, the new 8×32 mm Victory SF had a few minor tweaks over the larger and earlier appearing 42 mm models, though, most notably to the eyecups, which are now a lot firmer and more comfortable to rest one’s eyes against. Let’s take a closer look at this state-of-the-art 8×32. The magnesium alloy chassis is covered in textured, non-slip rubber. Nor are there thumb-rests on the underside of the binocular. That’s sensible in my opinion, as the binocular is not heavy and pretty much anyone could hold it steady. Zeiss has maintained the open-bridge design for this smaller binocular too, so there’s ample space to wrap your fingers round thanks to the very long barrels of the instrument and leaving the index finger free to access the central focus wheel. The twist-up eyecups are finished in soft rubber and are supremely comfortable to press your eyes against, even after hours in the field and the generous 19 mm of eye relief makes use with glasses a pleasurable experience. To improve the ergonomic experience, Zeiss engineered the SF to be back heavy  – the so called Ergobalance concept – so that more of the weight of the binocular rests nearer your eyes giving less strain to your arms. While this undoubtedly helps relieve arm strain, its advantage vanishes the second you hang the binocular normally around your neck! The large centrally placed focus wheel is silky smooth, quick and easy, with 1.6 clockwise turns bringing you from closest focus to infinity and a little beyond. Close focus is about 2 m, good but certainly not exceptional in today’s market. The right eye diopter adjustment is made by pulling out the focus wheel, turning the dial to your desired setting before popping it back in again. Optically, the Zeiss Victory SF packs a very powerful optical punch. The fluorite containing Schott glass objectives, proprietary full multi-coatings and a built in field flattening optical system all help to deliver images of the highest contrast and

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sharpness, and the enormous field of view – a full 8.8 angular degrees – creates an extremely immersive perspective. The wide field of view is ideal for viewing landscapes. It’s also a world-class birding binocular. Chromatic aberration is very minimal and the image, generally, falls into the ‘cold’ category owing to the flat light transmission across the visual spectrum. Any downsides? Well, quite a few owners report black outs/kidney beaning caused by the complex ocular design and their long eye relief, necessitating more careful eye placement while glassing. By anyone’s standard this is a world class binocular, but it doesn’t come cheap. Expect to pay $2500 for the privilege of owning one.

The Zeiss SFL 8×30. (Image Credit: Henrik Rundgren)

Some owners of the Zeiss Victory SF 8×32 complained that it was a tad too big for an 8×32 format. Others hankered after a smaller and more lightweight equivalent to this high-performance glass. Zeiss listened to its fan base by bringing to market an even smaller and more compact binocular in the form of the Zeiss SFL 8×30, which saw first light in the Spring of 2023. Weighing just 460 g, the Zeiss SFL is packed full of state-of-the art optical features. Zeiss engineers, started with the Victory SF 8×32 and re-designed it from the bottom up. Gone is the open bridge chassis, replaced by a single thin bridge. The lenses are smaller and thinner too, shaving off a significant amount of weight. The built in  lockable diopter was replaced by a more conventional, low-tech diopter ring under the right ocular lens. Ergonomically, Zeiss incorporated the SF (SmartFocus) concept introduced in the Victory SFs which includes placing the focus wheel in front of the bridge and a focus speed that takes only 1.4 turns of travel between from closest focus to infinity.

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The binocular features Zeiss’ LotuTec coating that helps to repel water droplets and dust particles to ensure a clear view at all times. With 90% light transmission and ZEISS T* multi coating, you can clearly and precisely recognize details in the twilight, ensuring that you never miss a moment of the action. The field of view is not quite as impressive as the large Victory SF though, but an 8.0 degree field with edge-­ to-­edge clarity is nothing to be sniffed at. Although its dimensions are quite close to the venerable Leica Ultravid HD Plus 8×32 discussed earlier, the Zeiss SFL 8×30 is about 100 g lighter and has much better eye relief (18 mm) making it considerably more comfortable using eyeglasses. Any downsides? Well, it might prove a bit too small for those with larger hands and some early reports suggest that some kidney beaning (blackouts) may occur if your eyes are not set squarely with the instrument’s exit pupils. Other than that, there’s really nothing to dislike. Expect to pay $1500 for this highly advanced wonder glass.

World Class Companions from Swarovski

The Swarovski Habicht 8×30. (Image Credit: Paul Wehr)

No discussion on compact binoculars would be complete without a consideration of some amazing instruments offered by the famous Austrian firm Swarovski Optik. Founded in 1949, Swarovski has worked extremely hard to bring state of the art optical products to their adoring fans the world over. Today, they are arguably the manufacturers of the finest optical wares money can buy. If you’re into classic designs, Swarovski offer a range of state-of-the-art Porro prism binoculars. I speak of course of the Habicht series of binocular, newly upgraded to be fully waterproof and fogproof, unlike many other Porro prism models on the market today. These instruments have been continually manufactured by Swarovski and are among the most economical models offered by this market leading company. Indeed, of the big three – Leica, Zeiss and Swarovski – only the latter continue to manufacture classic

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Porro prism designs for their discriminating customers. Tipping the scales at 540 g, the 8×30 Habicht delivers a field of 7.8 degrees with superb central sharpness rich in contrast and detail. Fans of the Habicht revere the palpable three-dimensional views the Porro prism design guarantees. Total light transmission in these models is truly astounding – a whopping 96%, the best in the ndustry! The reader will note that Swarovski attain this superlative optical performance using a classic two-­ element objective design with no ED glass elements in the optical trains. How is this achieved? By incorporating the best figuring and polishing techniques of the optical elements and then treating them to the best optical coatings money can buy. Owners rave about the crystal-clear optical performance of these instruments, which show hardly a trace of chromatic aberration even under the harshest of lighting conditions. Anything to dislike about the Habicht 8×30? Not much, but some owners bemoan the overly stiff focus wheel on the instrument, caused, they allege, by its sealed and nitrogen purged optics. Many owners have also commented on its propensity to throw up glare in certain lighting situations. I suppose with a 96% light throughput, this kind of thing comes with the territory. The Habicht 8×30 retails for about $1300, so is not cheap, but many would say you get what you pay for. If the 8×30 Habicht is not to your liking, perhaps the stylish Swarovski CL Companions will be. The Companions come in two flavors – 8×30 or 10×30. Weighing slightly less than the Habicht at 490 g, the CL Companion has undergone a complete redesign since the first models were introduced back in 2011. The first-generation CL companions got very mixed reviews. Some loved them but others complained that their fields of view were not that impressive, especially coming from a top manufacturer like Swarovski. Others noted that they exhibited far too much veiling glare in critical tests.

The Swarovski CL Companion 8×30. (Image Credit: Chuck Hill)

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The second-generation CL Companions arrived in 2017. These had a slick new design with wider fields of view (7.6 degrees for the 8× instrument and 6.2 degrees for the 10×). Both are a pleasure to hold, with their textured rubber armoring giving a firm grip, and available in two color schemes, green and anthracite. The twist-up eyecups have only two positions: fully retracted or extended, though one can position them at any intermediate position stably. Eye relief is decent 16  mm. Many individuals found the diopter adjustment a bit fiddly however– to set it, you need to push in the center of the focus wheel whilst simultaneously looking through the instrument. The deeply ridged focus wheel is easy to use in all weathers – even with gloves on. 1.5 revolutions clockwise takes you from closest focus to infinity. That said, with a close focus of only 3 meters, this is not the best instrument if you wish to watch butterflies at close quarters. Reported image quality is excellent though, with impressive edge-to-edge sharpness. Color fringing is absent for the most part, and the images have a natural, neutral tone. And while the field of view is not class-leading by any means, it certainly is immersive and engaging. These work well in good lighting conditions but their high light transmission (of the order of 90%), ensure they will perform reasonably well for a while after the sun sets. Each CL companion comes with removable tethered objective lens covers and a good quality rain guard, but the supplied strap leaves a lot to be desired. Better to buy Swarovski’s higher quality neoprene strap that can be affixed or removed in seconds thanks to the thoroughly redesigned attachment lugs on the sides of the barrels. The Swarovski CL Companions come in a choice of three accessory packages  – Wild Nature, Urban Jungle, and Northern Lights. Retail prices start at about $1400. Swarovski are also world leaders in the manufacture of some of the most advanced compact binoculars on the market. Their EL line of binoculars long remained their flagship models, only superseded fairly recently by their new NL Pure instruments. Let’s first look at their EL range. Swarovski EL binoculars are high-end, premium quality binoculars designed for outdoor and wildlife observation. They are renowned for their exceptional optical performance, ruggedness, and durability. Here are some of the key features of the Swarovski EL binoculars: Optical Excellence: Swarovski EL binoculars use high-quality lenses and coatings to deliver excellent clarity, sharpness, contrast, and color fidelity. They typically have a wide field of view and provide bright and clear images even in low light conditions. Ergonomic Design: The EL series features an ergonomic design that makes them comfortable to hold and use for extended periods of time. They are typically lightweight and balanced, with an open-bridge design that provides a good grip and easy access to the focusing wheel. Waterproof and Fogproof: Swarovski EL binoculars are typically waterproof and fogproof, which means they can be used in all weather conditions without any damage to the optics.

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Build Quality: Swarovski EL binoculars are built to last, with a rugged construction that can withstand rough handling and extreme outdoor conditions. They are typically made of durable materials such as magnesium alloy and feature a ­rubber armor coating that provides a good grip and protects the binoculars from scratches and bumps. Advanced Features: The  Swarovski EL binoculars come with advanced features such as Swarovision technology, which provides a wider field of view and improved edge-to-edge sharpness, and Field Flattener lenses that eliminate distortion at the edges of the image. Overall, Swarovski EL binoculars are a top choice for serious birdwatchers, hunters, and outdoor enthusiasts who demand the best optical performance and build quality from their binoculars. Shortly after Swarovski launched their even more advanced NL Pure line of binoculars, they discontinued the EL 8×32. Rumors abounded online as to why this might have been the case. Many users reported excessive glare in these instruments, where otherwise excellent images were washed out anytime the instrument was pointed near back-lit targets. Whatever the reason for its discontinuation, the company quickly developed the new NL Pure line of binoculars, of which the 32 mm models were the last to be brought to market. So what did the NL Pure line bring to the table that the EL range did not? Optical Performance: Both the EL and NL Pure binoculars use high-quality lenses and coatings to deliver excellent clarity, sharpness, contrast, and color fidelity. However, the NL Pure range uses a new lens design called the Pure Fluoride lens, which offers even better image quality and improved edge-to-edge sharpness. Ergonomic Design: The EL and NL Pure ranges both feature an ergonomic design that makes them comfortable to hold and use for extended periods of time. However, the NL Pure range has a more streamlined design with a smaller hinge, which makes it more compact and easier to handle. Unlike the EL, the 32mm NL Pure instruments don’t have a locking diopter but it’s extremely rigid and won’t easily get moved out of place. Field of View: The NL Pure range offers a wider field of view than the EL range, thanks to its new lens design. This makes it easier to locate and track moving subjects, particularly in dense vegetation or other challenging environments. Weight: The NL Pure range is slightly heavier than the EL range, which can be an important consideration for those who plan to carry their binoculars for extended periods of time or over long distances. Price: The NL Pure range is more expensive than the EL range, reflecting its higher-­ end features and improved performance. Comparing the NL Pure 8×32 to the now discontinued EL model, you get a field of view of 8.5 degrees, a modest expansion of the EL’s 8.0 degree field. But you get less eye relief on the new NL Pure model (18 mm vs 20 mm). Overall light transmission has been improved by about 2% over the older EL (already at 90%), but it is doubtful whether the average user would ever notice that in practice. It’s also noteworthy that the new NL Pure 8×32 actually weighs 60g more than the EL 8×32

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(580g vs 640g) but most owners would concede that the former has better haptics. Did Swarovski resolve the somewhat erratic stray light behavior issue in the NL Pure? As far as I was able to discern the answer is no, based on several experienced user reports I’ve read. But that doesn’t seem to stop folk from investing in this model. Optical instruments like this demand top-drawer money. Expect to pay $2700 to own this Austrian beauty.

A State-of-the-Art Porro Prism Binocular from Nikon

The superlative Nikon E II 8×30

Now for something rather special. Introduced back in 1999, the Nikon EII was offered in two models, an 8×30 and a larger 10×35. What distinguishes these units from their lower-priced econo-models are their state-of-the-art optics, very large fields of view and exceptional build quality. As you may have guessed, this kind of quality doesn’t come cheap, but I hope you’ll agree that they still represent exceptional value for money, especially when you factor in how much an equivalent roof model would cost to even approach the quality of these amazing Porro prism instruments. So if you’re in any doubt about my verdict on the 8×30, it gets my top recommendation. What follows here are detailed notes on its ergonomics, optics and handling in the field.

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The box containing the instrument looks seriously plain Jane; just simple, brown carboard. But when you prize it open, you get a very fetching soft faux leather case containing the instrument. The case is absolutely useless though; there’s no strap and it won’t protect the instrument from the elements adequately. All the paper documentation, including a multi-language instruction manual, warranty details etc. are found at the bottom of the box. The binocular comes with a Nikon logoed plastic rain guard, and loosely fitting plastic objective covers. The high-quality neck strap appears to be made from woven cotton and has a matching logo inscribed, “Nikon since 1917.” The Nikon E II 8×30 is exceptionally easy to hold in my medium sized hands. It’s also very lightweight, thanks to its die cast magnesium alloy chassis, tipping the scales at just over 500 g. The fit and finish is excellent, with a strong retro look, which I adore, though it must be pointed out that the instrument is not rubber armored. I suspect that this was avoided to maximize the aesthetic appeal of the binocular in order to make it look and feel like a true classic glass. Indeed, I seem to have garnered similar ideas about the Nikon Monarch HG 8×30; it too is lightly armored for maximum aesthetic effect. The diopter setting is found under the right ocular. It moves with a fair amount of friction and holds its position very well indeed, even after months of frequent use. The focus wheel works very smoothly, with zero play or backlash. It goes through just shy of 1.5 revolutions clockwise from one end of its focus travel to another. Depth of field is impressive, especially when presented with such an enormous field of view. The eyecups are made of soft rubber that seem very durable. The ocular field lens diameter is good and large  – 20  mm. The cups can be folded down to accommodate eye glass wearers. Though I don’t personally wear eyeglasses while glassing, I did test to see if I could see the entire field with my eyeglasses on. I can report that it could just be done, but I didn’t find the experience particularly comfortable. Those of you who must wear eyeglasses would benefit from wearing more contoured spectacles with high-index glass. The serial number of my unit is 822,128, indicating a fairly recent manufacture. There has been some discussion about whether or not the anti-reflection coatings on the Nikon E II series have been improved over the years. Given Nikon’s tendency to improve their products without formal notification, I don’t see why they haven’t been modified since launching the product back in 1999. The ocular lenses are large and easy to square one’s eyes up with. They are multi-coated as seen from above: The objectives are reasonably well recessed and have a beautiful magenta hue in daylight. The Nikon E II 8×30 exhibits excellent suppression of internal reflections and I observed little in the way of stray light when I examined the exit pupils. Aiming at a bright streetlight after dark failed to show up any significant reflections. The same was true when I turned it on the Moon. The daytime images served up by the Nikon EII are outstanding! But to elaborate; the enormous 8.8-degree field of view produces a stunningly beautiful and uniquely immersive image. Sharpness is superb almost to the edge of the field and then, only mild field curvature and a bit of pincushion distortion creeps in to slightly distort the image. Some other reviewers say the sweet spot is about 75% of the field but I think that figure depends on individual

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accommodation. Younger individuals will most likely report an even bigger area over which the image remains sharp and well defined. The field is so large that it makes the 8.3-degree field of the Nikon Monarch HG 8×30 field seem small in comparison. Color correction is excellent: I detected none on axis and only the merest trace of lateral color observed under the most pressing of observing conditions, such as viewing layers of tree branches against a bright overcast sky. By the way, it achieves these stunning optics entirely without low dispersion (ED) glass, just like the highly lauded Swarovski Habicht Porros. Glare is also very well suppressed in this instrument, including annoying veiling glare that sometimes shows up in other binoculars while viewing in the open air when bright sunlight is streaming down on your target. Brightness is also very satisfactory, even while viewing objects in the late evening when its good glare suppression adds to its charm. As the guys from Allbinos.com measured back in 2015, it achieves a light transmission of the order of at least 90%, but its very neutral color cast indicates that the transmission graph is bound to be quite flat over much of the visual spectral range (410–700 nm). I measured close focus on my unit to be just 1.97 m, well below the advertised 3 m and fully in keeping with most roof prism models. This came as a genuine surprise to me, as Porro prism binoculars are not known for their good close focus. Of course, to get the most out of those close-up views, I found it necessary to reduce the IPD of the instrument to mimic the natural ‘crossing of the eyes’ that happens as an object is placed very close to the body. As discussed above, the 3D images served up by this Porro prism binocular will knock your socks off! I’ve enjoyed countless adventures over the last year glassing open fields, watching Jacob’s sheep and their beautiful new-born lambs enjoying the warm spring sunshine, and admiring the finest details on their black, brown and white fleece. In winter I’ve enjoyed glassing snow-capped mountains and hills around my home. Your eyes become acutely aware of the topology of the landscape, as you view over hillocks and small depressions in the field. Mole hills transform into architectural wonders! One of the great virtues of instruments such as this, is the significantly reduced amount of time you spend focusing and the increased time spent just observing! In a forest say, you focus once and, more or less, forget it! These special properties also make it the ideal binocular for viewing landscapes. I have been bowled over by the sheer amount of information each image relays to my eyes and the super large field helps reel in many unexpected visual trinkets. For example, one afternoon, I was admiring the gorgeous lime-green tint of the young leaves on a large horse chestnut tree some 50 yards away, only to watch in sheer amazement as a group of noisy Oystercatchers were captured flying across the valley in the deep background, some 300 yards distant. I could easily make out their long, ruddy beaks and black and white plumage as they raced through the air at breakneck speed. I have even learned to spot airborne Starlings, Redwings and even the odd Jay in the same way, and over very long distances. It’s the combination of excellent, glare-free optics, great focus depth, palpable 3D impressions and class-beating field size, that creates the most powerful Majesty Factor I have personally experienced in any binocular, period.

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Panning the edges of large swathes of forest is supremely comfortable with the Nikon E II 8×30. I have yet to experience any blackouts or the stomach-churning rolling ball effect I often experienced while observing with the Nikon Monarch HG 8×30. It’s also very well collimated. Any niggles at all? Not really! OK, It’s not waterproof but I’ve found this is not a significant drawback. Indeed, I’ve discovered a way to render such instruments effectively fog proof by storing them in desiccant-­ laden Tupperware containers that I describe more fully later in the book. I must declare that the Nikon E II 8×30 is my favorite instrument for all kinds of daytime activities. Compared with top roof prism models, it represents a most genuine bargain. Every time I bring it to my eyes, I’m amazed that such a simple optical design can create such a magnificent image without resorting to all the optical ‘electrickery,’ to borrow a phrase from Cat Weasel, needed by roof prism models just to compete with such an instrument. The Nikon E II is becoming more difficult to source and is becoming more expensive as a result. I note that several Nikon sites no longer advertise it. I received mine from Dutch stock, so I know they can still be found at reasonable prices. For sure, I’m very late to the party, but if you want to experience that superlative optical performance in a neo-classical compact porro design, now would be a good time to acquire one……………before they’re all gone! Ok, so that was a brief survey of some of the more notable compact binoculars available to today’s birder or outdoor enthusiast. It certainly is not exhaustive but merely representative of what is available. In the next chapter, we’ll do a similar survey of the full-size binocular market, which currently enjoy even more popularity than the compact designs discussed here.

Chapter 5

Full Size Binoculars

Though compact binoculars in the 30–33  mm aperture class have been steadily increasing in popularity due to their lighter weight and decent light grasp, it is arguably full-sized binoculars with apertures between 35 and 43 mm that have gained the greatest popularity among birders, hunters and even stargazers. There are a number of good reasons for the popularity of this class of binocular, as for many people, it offers the best compromise between functional performance and portability. Others would also argue that they offer the best bang for buck. Consider a typical modern 8×42 mm roof prism binocular. It will have an exit pupil of 5.25 mm, so considerably larger than an 8×32 in comparison. The larger exit pupil on the 42 mm binocular makes it easier to center your eye in the image. As a result, the majority of people will find viewing though the 8×42 more comfortable and intuitive than an 8×32. In addition, the larger objective size will gather more light than a compact model, and so will be a much better optical aid in low light situations or for use in stargazing, where a bigger exit pupil and large aperture objectives both conspire together to capture as much light as possible. The price you pay for this kind of performance is a larger carrying weight. Typically, a regular 8×42 will weigh about 30% more than an average 8×32 model. Full size binoculars remain very popular with birders, hunters and hikers because they are still relatively portable and can be stored away in a backpack or just worn around the neck. In this chapter, we’ll be taking a look at some representative models from the various price classes. But before we do that, I’d like to discuss a very nice cost-effective Porro prism binocular from Nikon; enter the Action EX 7×35.

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_5

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Ultra-stable Super-Wide Angle Viewing from Nikon The Japanese optics giant Nikon has produced some incredible binoculars over their century + years of being in business. What I think they really excel at is designing and marketing sweet binoculars at very competitive prices. That’s exactly the sentiments I felt towards their very economically priced Action EX 7×35 after spending a few days with it in the field. You might think a 7×35 format would be lightweight and streamlined: not so with this binocular! Weighing 800  g, this is one chunky binocular, overlaid as it is with a very thick rubber armoring which contributes to its wet weather resistance. This instrument is o-ring sealed and purged with dry nitrogen gas making it fully water- and fog proof.

The Nikon Action Ex 7×35 Package

Nikon states that the Action EX series have multi-layer coatings on the lenses and prisms ensuring high light transmission. One good way to test the effectiveness of these coatings is to aim the binocular at a bright artificial light source after dark and examine the images produced. I was glad to see very minimal internal reflections – and certainly less than the lower priced Aculon series marketed by Nikon. Still those coatings weren’t nearly as good as the Japanese-made Nikon E II series which cost considerably more.

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The large centrally located focus wheel moves very nicely with no free play or backlash. One and a quarter turns clockwise brings you from closest focus to beyond infinity. Unlike classic Porros, which usually come with fold-down rubber eyecups, the Nikon Action EX has modern twist up cups with three detents. Eye relief is a very decent 17 mm. I tested them while using my eyeglasses and was comfortably able to access the entire field. The ocular lenses are very large and easy to center your eyes in. The objective lenses are also very deeply recessed, further protecting them from stray light, dust and rain. Some may think the Action EX 7×35 is overbuilt. I really don’t think so. Yes, it’s quite heavy for its relatively small aperture but it feels exceptionally sturdy in the hands and its 7× gives very stable views which partially negates its bulk mass. Optically, the Nikon Action EX 7×35 is quite impressive: bright, sharp across a good chunk of the field with very good contrast. This binocular also controls glare very well. It is, for example, noticeably better than the less expensive Aculon models in this regard. The outer field does display quite pronounced field curvature, but I think this is quite acceptable given the fact that the field of view is a whopping 9.3 degrees. Depth of field is impressive too. I quickly became consciously aware of how little I had to refocus the instrument as I scanned the hills around my home. Anything beyond about 45 yards is sharply in focus. On the afternoon the binocular arrived it was a dull, overcast and drizzly late October day, but the Nikon Action EX 7×35 seem to take it all in its stride. I scanned the leaden skies in the open fields near my home and quickly picked up the silhouette of a hovering raptor, which I was later able to identify as a Peregrine Falcon from its fanned out tail feather. The enormous field of view allowed me to track the bird as it moved off toward the hills. At one stage the Peregrine entered the same field as a Buzzard which looked enormous in comparison. Nikon quote the close focus on the Action EX 7×35 to be 5 meters but I found that it is well under 3 meters! I also found the Nikon Action EX 7×35 very useful during a few forest walks. This is where the field curvature and enhanced 3D effects combine to create incredibly vivid images of treescapes with even closeup tree trunks being sharply focused. Absolutely exhilarating! As good as this binocular is for daylight glassing, I found it most excellent for stargazing too. With a decent magnifying power of 7× and 35  mm objectives providing a 5  mm exit pupil, not to mention its enormous 9.3-degree true field, the Nikon Action EX 7×35 throws up wonderful views of the night sky. On a dark, moonless night, I enjoyed sweeping the Milky Way through Cygnus, Perseus and Cassiopeia. The dazzling Pleiades star cluster looked rather small in the enormous field of this binocular. Ditto for the Hyades beneath it. The effects of field curvature are quite pronounced near the field stops but that’s a small compromise when you consider the modest cost of the instrument and the more than generous field of view. Quite simply, there is plenty to see in each new field of night sky. The Nikon Action EX 7×35 is an excellent bargain at $150.

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 Great Entry-Level 8×42 Roof Prism Binocular A from Celestron

The Impressive Celestron Nature DX 8×42

I’ve met many people who want to enjoy birdwatching but don’t want to spend a fortune doing so. If that’s you, you’d do a lot worse than checking with Celestron Nature DX 8×42 out. These tried and trusted binoculars provide a great birdwatching experience at a bargain price and have enjoyed many awards and solid recommendations over the years as a great entry-level birding binocular. Having tested a few of these, I must confess to agreeing with them. This well-thought-through binocular delivers impressively sharp and bright images, smooth and easy focus adjustment, and a whole host of other ergonomic virtues. If your birdwatching interest eventually becomes a passion, you will likely want to upgrade to a better model, but this instrument will take you a long way towards achieving your goals and without breaking the bank. The Celestron Nature DX is packed full of decent optical components essential for the functioning of a roof prism binocular. The lenses are fully multicoated, the BaK4 roof prisms are phase coated to increase brightness and image contrast. The polycarbonate chassis is o ring sealed and nitrogen purged so it can be used in adverse weather conditions, overlaid by a green colored rubber armoring for additional grip. However, in my hands, it feels slightly more plasticky and somewhat less grippy than more expensive models. The Nature DX 8×42 weighs only 630 g, very light for a full-sized binocular. This generally makes them very comfortable to hold. However, they are somewhat small in stature, so those with larger hands might struggle a bit using it. The twist

One of the Best Budget Binoculars on the Market: The Barr and Stroud Savannah 8×42

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up eyecups provide 17.5 mm of eye relief – good news for eye glass wearers – and the field of view is a very decent 7.4 degrees – nearly ideal for most birding activities. Images in the center of the field are sharp, contrasty with good control of chromatic aberration. The sweet spot in this instrument is in the central 50% of the field. I really like the Nature DX’s focus knob, which moves smoothly and accurately with just enough traction to stop when precise focus is achieved. One of the biggest challenges facing newbie birders is learning to quickly get their binoculars properly focused on a bird before it decides to fly off. I’m glad to say that this focuser will teach you those skills well. The right eye diopter is a bit on the stiff side though. This does make minor adjustments a bit more challenging. Thankfully for most folk, you’ll have to make this adjustment once. While using the Nature DX 8×42 after dark, I did notice some prominent internal reflections and more diffuse light around a sodium vapor streetlamp but less so on a full Moon. But it performs neatly on the stars so long as you keep the brighter luminaries within the central sweet spot. All in all, the Celestron Nature DX 8×42 and its higher power sibling, the 10×42, are very decent binoculars to allow you to enjoy the great outdoors. I’d say they’re a decent bargain at $170.

 ne of the Best Budget Binoculars on the Market: The Barr O and Stroud Savannah 8×42 When I first moved from reviewing telescope optics to the world of binoculars, I sought advice from an experienced birder living nearby my home who could recommend a decent entry-level instrument to get me started. He recommended I try a model from Barr and Stroud; not the old Glasgow firm which served the British Navy in two world wars but the modern company producing a range of roof prism binoculars from their factory in China. My first roof prism binocular purchase was the Barr and Stroud Sahara 8×42, which really impressed me and whetted my appetite for more sophisticated models marketed by the same company. That led me first to the Sierra 8×42 with its phase coated optics, which I could immediately discern when I compared it to the non-phase coated Sahara, that showed superior brightness and contrast. From there, I took a chance on the slightly more expensive Savannah 8×42, which literally blew me away with its enormous field of view and razor-sharp optics. This was my first encounter with high-quality optics and inevitably led me to begin testing a large range of binoculars in different price categories and sizes to build a decent portfolio for the writing of this book. After 5 years of testing, I remembered that Savannah binocular that had stoked my interest on binocular optics and decided to order another unit up to see how it would hold up considering my experiences with other models. Would I still be as enamored about the Barr and Stroud Savannah 8×42 after all these years? The instrument cost me just £129 new.

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The Barr & Stroud Savannah 8×42

When the package arrived, I was filled with a sense of child-like excitement, as I opened the colorful box containing the hard clamshell case housing the instrument. All the goodies I remember finding in my first Savannah binocular were inside; an instruction sheet, warranty card, neck and carry case strap. The instrument was stored inside a small plastic bag with the rubber rain guard and ocular covers already attached. The instrument was just as I remembered it; a rather Spartan polycarbonate chassis covered in a thick rubber armoring. This is one sturdy binocular built for the great outdoors! The eyecups were just as I remembered too: they twist up and rigidly lock into place with a reassuring click. Eye relief is a very comfortable 18 mm. That means you can easily access the entire field of view using eyeglasses as I was able to do. The central focus wheel is great; large, smooth, accurate turning with no free play encountered while racking it back and forth through its focus travel. Two full anticlockwise rotations bring you from nearest focus to infinity and a wee bit beyond. I’ve always been impressed with the focus wheels on all the Barr and Stroud models I’ve test driven over the years and this one was no exception. They are well engineered and easy to negotiate with just a single finger. The diopter setting is unusual: located just ahead of the focus wheel, the ring is marked with + and − to get you started and has a generous compensation range of +/−4. I note that the Swarovski’s new flagship NL Pure models have a similar mechanism. If I’m being critical, it can be easy to accidentally rotate it out of position owing to its proximity to the focus wheel, but a little practice will remedy that. Memorizing your ideal setting is a good idea.

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The objectives are very decently recessed to protect the lenses from rain, wind-­ borne dust and peripheral light. The ocular lenses are nice and large, making centering of your eyes child’s play. The single bridge is big and bulky making holding the instrument a little bit more challenging than open bridge designs but again your hands will quickly find their happy place. As I went back and read through my journal notes about this instrument, I was struck by how many times I wrote words such as “brilliant,” “excellent,” “immersive” and “compelling.” But these were written as a complete tyro; what did I know about binocular optics in those early days? I began, as ever, by directing a bright beam of light through the binocular to see how well it handled. Just as I reported in my first encounter with the instrument 4 years ago, the results were excellent; one of the best results I’ve personally seen in fact, there was very little in the way of internal reflections, no diffused light around the beam and only the tiniest hint of a diffraction spike. Testing the instrument on a bright sodium streetlamp showed no significant reflections and no contrast-­robbing diffused light around the lamp. Next, I looked at the exit pupils of the Savannah and the results were also very good: round and with very little encroaching of peripheral light. The big surprise for me was the view through the Barr & Stroud Savannah 8×42. It has a great, big sweet spot that I’d estimate to be about 70% of its very large (8.1 degree field) field, after which mild field curvature begins to encroach. But even the edges are acceptably sharp. Contrast is excellent and glare suppression exemplary. Indeed, when I compared the views through this economy binocular to the GPO Passion ED 8×42, I concluded that I was looking through substantially the same optics. It too has the same sized sweet spot and displays mild field curvature in the outer field of view. The Savannah was also just as good, if not a tad better at suppressing all kinds of glare, both in bright sunny conditions and on dull overcast days. I conducted more tests under the stars, where I was able to verify that the collimation of the Barr & Stroud Savannah was spot on. Stars remain respectfully tight within the central 70% and begin to morph slowly owing to field curvature and mild astigmatism as the field stops are approached. Only the last 10% showed noticeable morphing but I deemed these results very positively indeed. The Barr & Stroud has excellent close focus: I measured it at just 1.8 m, so great for exploring the nearby landscape like a long-range microscope. Indeed, this kind of activity is much better suited to roof prism models compared with their Porro prism counterparts. The Barr & Stroud Savannah 8×42 makes for an excellent birding binocular, with its smooth responsive focuser. Indeed, I’ve enjoyed watching a group of Jays gathering acorns just a few hundred yards from my home. I’ve also enjoyed glassing of the somewhat elusive Kingfisher up at the pond, with the excellent sharpness making light work of picking up its beautiful blue and orange plumage. It’s also great for scanning the hills around my home. It’s decent aperture and large exit pupil make it a very capable astronomy binocular too. I spent an hour outside with it,

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enjoying the glories of a last quarter Moon in the early hours of October 18 2022. Showpieces of the sky presented excellently in this instrument, such as the Pleiades and Hyades and, owing to its very well corrected field of view, I was able to admire the preternatural beauty of the Sword handle in Orion and the Belt stars in a single field. In conclusion, I can’t recommend this instrument highly enough! Of course, there will be sceptics who won’t lift a finger to buy a unit up and do some tests, but that’s their loss. With an age of austerity now upon us, the Barr & Stroud Savannah 8×42 will help a great many individuals enjoy the natural world at a price that they can afford. Buy from a reputable dealer and ask them to inspect the binocular to ensure the eye cups, focuser and diopter compensation ring are all working as they should before they ship it out. I guarantee it will put a smile on your face!

Low-Cost Porro Prism Binoculars from Olympus The Japanese optical giant Olympus has been trading for over a century and is perhaps better known for their cameras and lenses than their binoculars. In recent years, Olympus has brought to market a variety of entry-level and advanced binocular models to meet the demands of the growing sports optics market. Their S (or DPS I) line of Porro prism binoculars come in two flavors; an 8×40 model and a larger 10×50 instrument. These have fully coated optics and BK-7 prisms. Their more expensive Pro line include both roof prism binoculars and Porro prisms  – the so called EXPS I line – have higher quality BAK-4 prisms and fully multicoated optics. I canvassed the opinion of Welsh amateur astronomer, Rob Nurse, from Cardiff, who enjoys using his Olympus DPS I 8×40 for casual daytime viewing and stargazing at night. “Having tried out many handheld, general purpose binoculars over the past couple of years, including the likes of Nikon and Pentax through to several “vintage” Russian Tento and even East German Military Leica binoculars (very weighty), I think I now know what makes for the ideal pair  – at least, for my requirements. While some of these were very good, and some not so, they all had their own foibles. A couple even came with built-in wildlife on the internal optical surfaces. I finally settled on the Olympus DPS I 8×40 binoculars because they offer a relatively ultra-wide and flat field of view (8.2°) and are suitable for a range of subjects from sports to birding and general nature study. They work very well in low light situations with a relative brightness index of 25, meaning that they can be classified as night-vision binoculars, therefore most suitable for astronomy, my particular interest.

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The Olympus DPSI 8×40. (Image Credit: Rob Nurse)

Although these Olympus DPS I binoculars are apparently fitted with so-called “inferior” Bak7 prisms, there is no noticeable degradation of light, the image quality appears to remain intact over the whole field. Maybe Olympus has used high quality anti-reflective coatings on the prisms, or they have used good grade Schott glass. Either way I think they are a match for Bak4’s. The DPS I delivers a very sharp and well-defined field stop. There is slight pincushion distortion though it’s only noticeable when de-focusing on say a swathe of grass where the coloration is uniform; but is quite acceptable to me. Focus down to 3 meters (10 ft) – very useful for observing birds in the garden, for example. No obvious added coloration – tone remains neutral if somewhat cool. Nice coatings on all outer optical surfaces. Compact and well balanced  – feels good in the hands. Large central focus wheel – precise. Solid fold down rubber eyecups. I would have preferred the more precise twist –up/down type but not a deal breaker. Very good contrast  – no obvious fringing (chromatic aberration). No ghosting or internal reflections that I could detect. Good baffling. In short, the only way be improve on these relatively inexpensive binoculars, would be to upgrade to the Olympus Professional EXPS I binoculars with Bak4 prisms, aspheric optics and twist up eyecups. For the marginal improvement in performance one would need to spend substantially more money, about £150 currently. A negative here is that they only have a 6.5° field compared to the 8.2° field with the Olympus DPS I. The bottom line is I think you would really need to be ultra-fussy to find much to trouble your observing pleasure using these Olympus DPS I 8×40 binoculars. Personally, I think they are the perfect binoculars for general use.” Intrigued by this report of the Olympus DPS I 8× 40, I decided to buy in one of their so-called ‘premium’ Porro prism models; the EXPS I 10×42. Unlike the DPS

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I models which only has fully coated optics and BK7 prisms, the EXPS I instruments featured BAK4 Porro prisms and a full multicoating in a sleek, ergonomically advanced chassis. Unfortunately, this more expensive Olympus model proved very disappointing. The first model I ordered up had very distorted optics on one side of the field. Intrigued, I bought up a second unit for similar testing. Lo and behold, it had exactly the same issue. Definitely not recommended!

A Super Deal from Nikon: The Aculon A211 8×42 While the Olympus EXPS I was a bit of a disappointment, the next binocular discussed here is sure to put a smile on your face. The Nikon Aculon A211 is an economical series of Porro prism binoculars that replaced the company’s Action VII models back in 2013. Nine instruments make up the Aculon series: 7×35, 8×42, 10×42, 7×50, 10×50, 12×50, 16×50 and two zooms: 8–16×40 and 10–22×50. I took a detailed look at the 8×42 model. Tipping the scales at 767 g, the Nikon Aculon A211 8×42 features multicoated optics and high-index BaK4 Porro prisms. Though not as well built as the more expensive Action EX series, the Aculon still has a decently thick rubber armoring, but unlike the Action EX models, it’s not waterproof. The focus wheel is smooth and responsive with less stiction than that found on the Action EX models. This is probably attributed to the fact that the Aculon is not hermetically sealed which makes it easier for the focuser to move.

The Nikon Aculon A211 8×42

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The Aculon has nicely designed twist up eyecups, though it has significantly less eye relief than the Action EX I tested. The 8×42’s eye relief is only 12 mm so this will be a tight fit for those who wear eyeglasses. So how are the optics? When I directed a bright beam of light at the binocular and examined the resulting image, I was relieved to see that internal reflections were quite well subdued, with very little in the way of diffused light around the light source. This was also the result I got – a few minor internal reflections – when I aimed the Aculon at a bright yellow sodium streetlamp after dark. Indeed, these results were significantly better than the 16×50 Nikon Aculon model I tested. Daylight images served up by the Aculon A211 8×42 are very good; images in the center of the field are tack sharp, with good contrast and color rendering. I encountered quite a bit of glare though while the eyecups were extended fully upwards, but I was able to dramatically reduce this simply by moving them down one notch. I encountered the same thing while testing out the Vortex Diamondback HDs. The 8-degree field pf view is impressively wide and quite immersive. Image brightness is good too. Independent tests have measured a light transmission on these Aculons of the order of 80% – identical in fact to the more expensive Action EXs from Nikon. And, as I’ve come to expect from good Porro prism binoculars, the 3-D effect was abundantly in evidence. The sweet spot is large on the Nikon Aculon A211 8×42, and even the edge of field performance was quite acceptable given the aspherical elements in the eyepieces. One thing I did notice while using the 8×42 Aculon during cold dry weather was the tendency of the ocular lenses to fog up, owing to their shallow eye relief. I was able to remedy this to some extent by applying a layer of Zeiss anti-fog spray to the ocular lenses which greatly accelerates the removal of the condensation. Indeed, I would recommend this strategy for any binocular that doesn’t have special hydrophobic coatings on the outer lenses. The Aculon does display quite a lot of off-axis colour fringing though- something to bear in mind if you’re sensitive to this. I was able to do a bit of stargazing with the Nikon Aculon A211 8×42. Observing on a cold November night with no Moon in the sky, I was quite impressed by its performance. About 60% of the field shows stars as tiny, focused pinpoints, after which field curvature and coma start to distort the images. Coma is quite high near the field stops. I enjoyed some great views of the Pleaides, Hyades and the glories of Orion, where their constituent stars presented in their faithful colors. Scanning the Milky Way through Cygnus, now high overhead, was also a very enjoyable affair. And even though the edge of the field is a bit distorted, it’s not nearly as bad as I’ve seen on some roof prism models costing three times its modest cost. I picked my one for less than $80 delivered; now that’s what I call a good deal!

Remarkable, Low-Cost 42 mm ED Binoculars from Svbony The Svbony SV202 10×42 ED arrived in a similar package to the smaller 8×32 ED model discussed in the last chapter. The binocular (with objective and ocular tethers attached) was carefully packed away inside a nicely fitting soft case, with a soft lens

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cleaning cloth, a well written instruction manual, a nice quality padded logoed neck strap. The box itself was nicely made, simple and attractive to look at.

The Svbony SV202 ED 10×42

Once I removed the binocular from the case, I was immediately impressed with the build quality of the binocular. Just like its smaller sibling discussed in the previous chapter, the 10×42 felt very solid in the hand and was covered in a tough, textured rubber armoring that once again reminded me very much of the Zeiss Terra ED binoculars I had seen. Inspecting the objective and ocular lenses, I could see that the magenta-colored anti-reflection coatings were smoothly applied with no sleeks or pits. Passing a torch inside the binocular showed a nicely machined and blackened interior with no sign of dust, fingerprints or other debris. The exit pupils were round with no signs of truncation and the area around the pupils was nice and black. Nothing to concern me here! The Svbony 10×42 ED feels very sturdy in the hand but is surprisingly light weight. Usually, the lighter models in the 10×42 class tip the scales at over 700 g but this model weighed in at just 698 g, which is good news for folk who want to travel light. The eye cups are wonderfully made, properly machined and twist upwards for non-eye glass wearers. There are three positions in all, with each detent locking rigidly into place. These are top notch eye cups, as good as I’ve seen on models costing several times the retail cost of this binocular. The centrally located focus wheel is constructed from metal and covered with a finely textured rubber substrate for easy gripping. Focusing is smooth and precise with zero play. It’s a little on the stiff side but very easy to negotiate, and I’m sure

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this will relax a little further with more frequent use. The focuser goes through 1.75 revolutions from one end of its focus travel to the other. The rubber tethered objective and ocular covers fit snugly over the lenses. I generally don’t use these in the field, but I’m reassured that should I employ them, they won’t fall off easily. The metal right eye diopter ring is also nicely machined and rotates smoothly but has just the right amount of tension to stay rigidly in place. Having taken it in and out of its soft case dozens of times over a few days of testing, it never budged a millimeter. Good job Svbony! As stated above, the anti-reflection coatings applied to the ocular and objective lenses has a strong magenta hue in broad daylight. They reminded very much of those found on the new Zeiss Victory SF binoculars. Like all good anti-reflection coatings, they ought to nearly disappear when viewed nearly straight on. In summary, the ergonomics of this binocular are second to none. Really well made, with a quality fit and feel right from the get-go! Beginning, as always, with my flashlight test, I directed an intensely bright beam of white light into the binocular and examined the image visually from a distance of about 3 metres away. Like the smaller 8×32 model, the result was excellent! There were no annoying internal reflections floating about, no diffraction spikes and no diffused light around the beam. It was clean as a whistle. Later, after dark, I aimed the Svbony at a bright sodium street lamp and was delighted (but not surprised) to see that it was clean, crisp with no internal reflections, diffused light and nary a sign of any diffraction spikes. These were great results, especially for such an inexpensive binocular. Indeed, I’ve seen much more expensive instruments fare a whole lot worse in this simple test. Good job Svbony! Even before I tweaked the diopter ring for my right eye, I was very impressed with the daylight images I was getting from this binocular. The instrument arrived on a very overcast, dull day, with the worst possible lighting. Despite this set back, I was immediately taken by the sharpness of the image and its very large sweet spot. Color rendition was very neutral and accurate. Eye placement was easy to optimize, and I encountered no blackouts. The image was bright and crisp with excellent contrast. I did encounter some veiling glare under these harsh lighting conditions, but I remember thinking to myself; “If this is the worse it could be, it’s really not too bad at all!” The next day afforded much better, sunnier seeing conditions and I was further able to test the mettle of this Svbony binocular. Early autumn leaves radiated with color and the image remained pin sharp across most of the field. The images snapped to focus with absolutely no ambiguity – a property I had noted in other high-quality binoculars. On a walk by the river, I was mesmerized by the clarity of water flowing around rocks with beautiful sharpness and very little glare. Later the same afternoon, when some cloud rolled in, I examined the hills located a kilometer or so away, and I did detect some chromatic aberration on the edge of some cliffs against a uniformly bright sky. I had seen this effect before in the Leica Trinovid HD 8×32. Boy was that binocular sharp, but it also showed some chromatic aberration on high contrast targets! More on this later.

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After a few days of using the Svbony 10×42 ED on long walks through the woods, along the riverbank and through open fields, I began to appreciate the silky smoothness of the focuser. The focus wheel’s slow progression makes precise focusing a breeze, and while it’s more suited to hunting than birding, I was still able to enjoy some amazing glassing moments watching a Buzzard taking to flight from a tall conifer tree on one of my local patches. As I related earlier, the Svbony does show a very small amount of chromatic aberration on high contrast objects, yet it delivers sharper images than a more color free binocular tested against it. This shows that absolute image quality need not be conflated with the degree of chromatic correction found in the binocular. I measured close focus to be 2.8 metres – longer than the advertised 2.5 meters, but something I wasn’t too bothered with, as I usually do close up glassing using 8× models anyway. The comparatively light weight of this binocular makes it very easy to hand hold in my medium sized hands. The binocular does show some glare in the most demanding lighting conditions, but I learned to control it better by firmly holding my eye sockets to the eyecups to minimize the entry of peripheral light into the optical train. Greens and yellows are especially well accentuated in the Svbony, with the binocular delivering excellent brightness to the eyes, even during fading evening light. No matter how enthusiastic one feels about a binocular during daylight testing, observing the night sky produces still further insights into the relative quality of the glass. Luckily, I enjoyed a couple of good vigils with the Moon out of the sky. Here’s what I found. Although it’s obvious that the Svbony 10×42 ED had a large, well-corrected sweet spot as seen in daylight glassing, it becomes much clearer by seeing how bright stars morph as they are moved from the center of the field all the way to field stop. My first opportunity came on the evening of Saturday, September 11 2020. Examining the bright yellow star, Capella, low down in the northeast at 21:45 local time, I was able to see that it remained pin sharp out to within~15% of the distance to the field stop, beyond which point it started to bloat. But even at the field stop the bloating wasn’t too bad and indeed, I was able to focus most of it out. I consider this to be a very good result, especially for the very reasonable cost of the instrument ($175). I believe this is attributed to the modest choice of field size employed in the Svbony. Many inexpensive models make the mistake of opening up the field too much, with the result that the outer part of the field becomes noticeably more blurred than the center of the field. And while the field of view of the Svbony 10×42 ED is not overly restrictive at 6.16 angular degrees, the designers did not fall into the trap of making it too wide. This greatly aids in the aesthetic appeal of the nighttime binocular field. Bright stars like Vega, Deneb, Altair and Arcturus, low in the west, showed their colors very faithfully. No secondary spectrum was detected within the large sweet spot. The large and sprawling Alpha Persei Association (Melotte 20) looked magnificent in this 10×42, as did the Double Cluster a little higher up in the sky. I enjoyed lovely views of the Great Andromeda Galaxy, the Coathanger asterism and

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the Engagement Ring, Finally, observing mighty Jupiter low in the south southeast shortly before 10 pm local time, I could easily resolve, by just handholding the binocular, all four ‘Medicean Stars’ to the east of the Giant Planet. While I had intended to view the Pleaides and Hyades sometime later that evening, it clouded over. Luckily though, the next night, Sunday September 12 2020, also turned out to be clear and indeed it remained so for much of the night, well into the wee small hours of Monday morning. Beginning about 23:00 h local time and ending about half past local midnight, I enjoyed a fantastic night observing with the Svbony 10×42. Though most of my observations were handheld, lying back in a recliner, I did perform one high resolution test centering Albireo in Cygnus in the field of view with the binocular mounted on my tripod. I was delighted to get a beautiful split of this wonderful color contrast double, the emerald and golden components showing up faithfully. Indeed, I took the opportunity to micro-tweak the diopter setting just a little while observing this celebrated binocular double. I enjoyed splendid binocular views of the globular clusters, M13 and M92 sinking lower in the west in Hercules. High in the east, magnificent Perseus was very prominent and I once again soaked up the views of Melotte 20, and the Double Cluster. The lovely open cluster M34 stood out beautifully with a good sprinkling of faint stars being easily resolved within its confines. After that I just relaxed and went cruising along the river of Milky Way starlight meandering its way from Cassiopeia in the northeast, continuing through Cepheus, Cygnus, Vulpecula, Sagitta and Aquila now sinking into the southwestern sky. Before ending the vigil, I moved from by back garden to the front garden, which faces east. The Pleiades was painfully beautiful in this binocular, the stars remaining pinpoint sharp and pure white as the driven snow. Moving the little asterism from the center of the field to the edge showed a drop off in illumination of its constituent stars. I found it easier to see this fall off under these conditions than during the day. Nothing bad to report here either, as this is a common feature in even top-rated binoculars I’ve tested in the past. Finally, with the Hyades rising over the Fintry Hills to the east of my home I was able to enjoy the horns of the Celestial Bull in their full glory. The field sparkled with stellar jewels of various hues and glories; red, orange, white and yellow. Just lovely! I’m so very glad I followed up on reviewing this larger sibling from the Svbony ED binocular duo. The little 8×32 ED impressed me, but this instrument is just plain extraordinary! It feels and behaves like a much more expensive binocular. Indeed, I would go so far as to say that it will compete favorably with the best mid-tier binoculars out there… no strings. Optically it reminded me very much of the lovely Leica Trinovid HD I owned and enjoyed some time ago. I don’t know why it is priced so low, but I do know quality when I see it and this wonderfully designed binocular exudes quality, both ergonomically and optically.

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The Svbony SV202 8×42 ED

In late 2022 Svbony launched yet another high-performance roof prism binocular in the form of the 8×42 ED which I also had the pleasure of testing and reviewing. Outwardly, it’s almost identical to the 10×42 model but actually tips the scales at 720  g, so slightly heavier. In my experiences testing dozens of models in this aperture class over the years, I’ve encountered many that look the part only to discover that their optics were, let’s just say, underwhelming. I’m delighted to report that the optics of the SV 202 8×42 ED did not disappoint! To give the reader an honest and thorough idea of how good this binocular is, I took the liberty to test it alongside two other instruments in the same aperture class: the Hawke Endurance ED 8×42 retailing at just over £200 and the more expensive GPO Passion ED 8×42 costing £404. First examining the image of an intensely bright beam of white light directed into the instruments from across a darkened indoor setting, the results from the Svbony SV 202 8×42 ED were really excellent! It stubbornly refused to show up any internal reflections, unlike the Hawke Endurance ED, which showed up some prominent ones in comparison. Nor was there any diffused light around the light source in the Svbony unlike the Hawke which was easy to see in comparison. Clearly, the Svbony has noticeably superior coatings and baffles to stubbornly block off these annoying optical artefacts. Now, when I compared the Svbony to the GPO Passion ED 8×42, the results were a lot closer but I must report that the Svbony also showed slightly better resistance to internal reflections than the GPO. Indeed, predictably enough, I obtained the same results when I turned the instruments on a bright full Moon and

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a sodium streetlamp after dark. Internal reflections and diffused light were quite obvious in the Hawke and much better in the GPO but I was still able to make out some weak internal reflections in the GPO binocular in comparison to the Svbony, which showed none in comparison. These are excellent results, and quite in keeping with the two other SV202 models I purchased and tested in my past evaluations.

Testing the Svbony SV202 8×42 ED (bottom) against the considerably more expensive GPO Passion ED 8×42 (top)

Next, taking a look at the exit pupils aimed at a bright, artificial light source, I was delighted to see that the large exit pupils on the Svbony SV 202 8×42 ED were perfectly round, with little in the way of light bleeds in their vicinity. The image is very bright and razor sharp across the majority of the field. The binocular shows lovely micro-contrast details. Images snap to focus with absolutely no ambiguity. You’re either in focus or out of focus. No fiddling required! Contrast and color rendering are also excellent. Glare is very well suppressed by not quite as good as the best binoculars I’ve sampled in the £800 + range. The view is wide (7.5 angular degrees) but not overly so. This makes the sweetspot proportionately larger in the 8×42 than either the 8×32 or the 10×42 models previously assessed. How big? I’d estimate that it’s razor sharp over at least 70% of the field, with mild field curvature and some barrel (negative) distortion creeping in as one approaches the field stops. But make no mistake about it, even at the field stops, the images of stars I assessed (discussed below) were tighter than I remember on the two earlier models I field tested.

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Comparing the views through the similarly-priced Hawke Endurance ED, the difference was obvious; the Svbony was noticeably sharper, had better contrast and with better control of both general field glare and veiling glare. Color correction was maybe a shade better in the Hawke though, but I’ve noted that some of the sharpest binoculars I’ve tested over the last 4 years have had some secondary spectrum bleed. Having said that, there is only the merest trace of it within the sweet spot but as one moves to the outer field, lateral color can often be picked up when viewing tree branches against a uniformly lit grey background sky; a harsh test for any binocular, however well made. Close focus was measured to be 2.27 meters, a little longer than advertised. On the many very dull, overcast days we experienced throughout October 2022, the Svbony SV 202 8×42 ED threw up superlative images. Colors in autumn leaves really popped, with no contrast-robbing glare to reduce the intensity of the views. Greens, tans and red colors seem to be enhanced under these conditions. Near dusk, these colors really become enhanced! Imaging fallen leaves at close quarters (within a few meters) really shows off the exceptional sharpness of this binocular. I attribute this to unusually good correction of spherical aberration. Indeed, to my eye, better spherical aberration correction is more desirable than a slightly softer but better color corrected image, as was manifested in the Hawke Endurance ED 8×42 tested alongside it. I detected no blackouts while panning large swathes of hillside with the Svbony 8×42 ED, unlike I encountered with the GPO Passion ED 8×42. I attribute this to simpler eyepiece design in the former. Under bright sunny conditions, the Svbony does throw up more in the way of glare, especially in the direction of the Sun, but although I’m especially partial to this kind of defect, it was never bothersome. Indeed, comparing my notes of observations conducted using a well-heeled Swarovski EL 8.5×42, I observed similar levels of glare under the same conditions. In another low light test, I compared and contrasted the images garnered by the GPO Passion ED and the Svbony. Observing at dusk and far into deep twilight, looking into the deeply shaded undergrowth of shrubs some 20 metres in the distance, I was unable to see any significant brightness differences between the instruments. That’s good news considering the former has a light transmission of the order of 90%. Whatever the precise light transmission of the Svbony SV 202 8×42 ED, it’s likely to be impressively high. They say good things come in threes. That’s certainly turned out to be a true adage in my experience with these SV 202 compact and mid-sized ED binoculars from Svbony. Furthermore, of the three I’ve tested and reported on, this new SV 202 8×42 ED has got to be my favorite. It’s an awesome binocular, especially considering its very modest pricing. It will make an excellent birding binocular, for example, where the finest optics are required to pick off the minutest details in your avian targets. It’s also a fine star gazing binocular with its great near edge-to-edge sharpness. It will do well in any situation; bright sunlight, or at dusk and dawn, so will also be useful as a hunting glass. Indeed, the Svbony SV 202 8×42 ED turned out to be the only full-size roof prism binocular I still use. High praise indeed!

An Open Bridge Wide Angle 8×42 from Barr & Stroud

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An Open Bridge Wide Angle 8×42 from Barr & Stroud

The Barr & Stroud Series 8 8×42 Open Bridge Binocular

Of all the modern formats used for recreational glassing, the 8×42 continues to be a firm favorite amongst birders hunters and even casual stargazers. And it’s easy to see why. A magnification of 8× provides a more stable view than 10×, and a 42 mm objective diameter affords a solid compromise between smaller and larger glasses that put constraints on low light use and weight, respectively. The Barr & Stroud Series 8 8×42 has a Magnesium alloy chassis overlaid by a thick, protective rubber armoring, with the sides of the barrels being ribbed for extra grip. The underside of the binocular has two prominent thumb indentations to help the user position the binocular as firmly as possible in the hands. The eye cups consist of high-quality aluminum with a soft rubber overcoat that are very comfortable to rest your eyes on. They twist up in three stages and firmly lock in place when fully deployed, giving a very generous eye relief of 17.5 mm, which renders them especially comfortable to use with eyeglasses. I elected to use them without glasses however, so kept them in their fully twisted out position throughout this review. The Series 8 was considerably lighter than I expected. Although the official specifications stated that it was nearly 800 g, I measured its weight at just 716 g; good news if you intend to do a lot of walking with this binocular. The main advantages of the open bridge design is easier handling, especially if you must use just one hand. The open bridge design allows the user to hold the binocular and turn the focus wheel with one finger compared with the more common single bridge design.

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Another advantage is much quicker engagement with your subject if you must grab the instrument suddenly and bring it towards your eyes. This renders them more desirable if you are cycling or hiking with the binocular hanging around your neck. However, these advantages are confined mainly to full-sized instruments in the 42 mm, 50 mm and 56 mm size categories. Moreover, the design quickly becomes less manageable in smaller compact models. If you come across a compact with an open bridge design, chances are it’s more for aesthetic reasons than anything else. In the hand, the instrument feels very solid and easy to handle. The focus wheel is a little on the stiff side, but moves very smoothly, with no backlash. I would describe the focus wheel on this Series 8 as being slow but very precise, taking about 2.25 revolutions to go from one end of its focus travel to the other. That would make the binocular more suited to hunting than birding. The diopter ring is located under the right ocular, as most instruments in this price class are. It’s quite large and easy to grip though, moving with just the right amount of tension to move it smoothly so that it stays rigidly in place. Like most of their more expensive binoculars, Barr & Stroud Series 8 showed a very clean image under these harsh conditions. There was little or no internal reflections, no annoying diffraction spikes and very little sign of diffused light around the beam. This indicates that the multi-layer coatings applied to the optical surfaces were doing their job suppressing internal reflections, and the lack of diffused light indicated that the glass used in the lenses and prisms of the Series 8 are made of quality optical components. Indeed, overall, it was just as good as their more expensive Series 5 Series 5 binoculars in all such tests! Examining a bright sodium lamp after dark garnered a very clean image, as expected, with no diffraction spikes and no internal reflections. Collectively, these tests augured well for the Series 8, as my subsequent optical tests during daylight and at night were to reveal. Examining the exit pupils of the Series 8 showed nice round pupils, with no evidence of truncation, though my test unit the right pupil did show a fairly prominent arc near the pupil. As I initiated my daylight testing I began to think about the reasons the Series 8 had significantly longer barrels than the Series 5 models I had previously reviewed. In particular, I wondered whether there was a difference in focal length in going from the shorter Series 5 binoculars compared with the Series 8 models. I fired off an email to Barr & Stroud’s parent company, Optical Vision Limited (OVL) asking for some information on this. I got an immediate response, stating that they would check with the optical engineers at their production site. A few days later, they sent me this response: Firstly, the optical system of the Series 8 is different from traditional compact binoculars. It’s actually based on a modified design from an older Swarovski binocular. It focuses using a positive lens, unlike the majority of traditional compact binoculars, which focus using a negative lens. That’s why the traditional compact binoculars are shorter than the Series 8 models, but the focal length of both these series is the same; the length of binocular is not to be confused with its focal length. Secondly, this kind of optical system is more suitable for open bridge designs, with the length of the barrels being longer, so the hand can hold it better.

An Open Bridge Wide Angle 8×42 from Barr & Stroud

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This kind of optical system will also have better light transmittance, as there are only three lenses in the objective housing. Compared with more traditional compact binoculars, which have a four-lens objective system. All very interesting! So how did it perform? Very well, as it turned out! The Series 8 delivers a very bright, sharp image with great contrast inside a very big sweet spot. Like all the more advanced Barr & Stroud binoculars I’ve tested, glare is exceptionally well controlled, including veiling glare. I was able to ascertain the latter by looking up at the topmost boughs of a conifer tree in my back garden under a bright overcast afternoon sky. Veiling glare appears as a bright arc of light at the bottom of the image which, in the worst cases, produces an unsightly milky fog that robs the image of contrast. The Series 8 is right up there with the best binoculars I’ve tested in this regard. The image has a warm cast that I found very pleasant. Greens, oranges and reds are particularly vibrant in the Series 8. Chromatic aberration is also very well controlled in this binocular. As I’ve discussed in previous reviews, I never judge a binocular on the basis of whether or not it has ED glass. I’ve seen plenty of examples of ED binoculars which show more chromatic aberration than well-made non-ED models. I was only able to detect very minor amounts of secondary spectrum on very high contrast objects and only by actively looking for it. I would say that this binocular has excellent control of false color and is simply not an issue. The enormous field of view in the Series 8 is very well corrected across most of the field, just like the Series 5 42 mm models. There is some field curvature and pincushion distortion as one moves from the center to the edges, but nothing extreme or out of the ordinary. Turning to low light performance, I tested the Series 8 against the Series 5 after sunset to look for any differences in brightness between the images. Going back and forth between the binoculars on shaded leaf litter under a bush about 30 yards distant, I felt the images were more alike than different, with perhaps the edge going to the Series 8. I wasn’t especially surprised by this result, as one would really need a sizeable (~5%) difference in transmittivity to affirm a noticeable distinction in image brightness here. The instrument has very generous eye relief, and is very comfortable to use with eyeglasses, which showed me the entire field with no problems. Close focus is also very good. The quoted figure is 1.9 m and that is pretty much what I measured it to be. This is a binocular you can use as an excellent long-range microscope to examine insects, rocks, fungi, and other natural curiosities close at hand. Comparing the ergonomics on the Series 8 to the Series 5 8×42 ED, I would say that the Series 8 is just that little bit easier to use. There are just more ways to grip the barrels and the very similar weight to the Series 5 binocular means that you won’t easily tire of carrying it about. The logoed neck strap accompanying the instrument is well padded and very comfortable to use. On the evening of October 14 2021, the skies cleared and I was able to enjoy a waxing gibbous Harvest Moon low down in the south, straddled by Jupiter above it

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to its left, and Saturn to its right. Talk about a wonderful naked eye vista! The image of the Moon was excellent through the Series 8, with only the merest trace of secondary spectrum seen at the lunar limb. The crater fields were very sharply rendered, and the image was entirely free of glare and internal reflections. Turning later to some bright stars visible in the sky like Vega and Altair, I was able to show that the Series 8 was able to maintain excellent sharpness over most of the very large field. Because I was able to refocus the stars down to crisp points near the field stops, it confirmed that the main off-axis aberration was field curvature. Moving the Moon from the center of the field to the field stops did show a moderate drop off in illumination, again, pretty normal behavior for a mid-priced binocular like this. I was able to image some very faint stars very near the Moon, providing still more evidence of its excellent control of glare. Observing some rich star fields, the binocular produced some very fine images of the Alpha Persei Association, with the field filled with innumerable stars of varying glory. The Pleiades was also a real treat even with the Moon in the sky. Their comely blue- white light came out beautifully in this 8× wide angle binocular. The generous field of view and well corrected field makes the Series 8 a particularly good instrument for sweeping up myriad Milky Way stars through Cygnus, Cassiopeia and Aquila. This is clearly a binocular that can be used equally well by day and by night, thus affording excellent mileage! The Series 8 8×42 clearly represents great value for money, with optics that closely match its ergonomics. It’s very easy to use and those who are fans of the open bridge design will very quickly take a shine to this instrument. Don’t be put off by its non-ED labelling. This binocular shows just how good traditional crown & flint can be when properly executed. It does exactly what it says on the tin and makes for a very worthy addition to Barr & Stroud’s line of high-performance binoculars. I would strongly recommend this to folk looking for a no-nonsense glass for the great outdoors and various astronomical excursions. The 10-year limited warranty offered by Barr & Stroud will also be honored, as I can personally attest to.

ED Binoculars from Hawke Hawke is a British family-founded sports optics company that has established a solid reputation serving the birding, hunting and hiking community. Over the last few decades the company has expanded its business, creating a US branch in 2007. Their binoculars, monoculars and spotting scopes have received high praise over the years, producing consistent optical quality at reasonable prices. The Hawke Endurance ED series has received various makeovers over the 15 years or so since its launch and represents the company’s entry level mid-tier optic. In this blog, I’ll be reporting on the Hawke Endurance ED 8×42 model, which is available in black or green.

ED Binoculars from Hawke

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The Hawke Endurance ED 8×42 has excellent ergonomics

The instrument arrived in a small, white box containing a high quality clamshell case (with strap), a logoed neoprene strap, lens cleaning cloth, a soft pouch, rubber rain guard, permanently attached objective lens covers and multi-language instruction manual. First impressions of the instrument were good. The magnesium alloy chassis is covered in a grippy dark green rubber armoring with prominent ribbing on the sides. The central hinge has very nice rigidity ensuring that your preferred inter pupillary distance is reliably maintained. The instrument feels solid in the hands even though it tips the scales at just over 700 g. I really like the metal focus wheel. Covered in large ridges, it rotates very smoothly and accurately with no free play. Just over two full rotations anticlockwise brings you from closest focus to infinity. The bridge is narrow – something I personally like very much, as it affords plenty of space to wrap your fingers around the barrels to hold the instrument steady. The twist-up eye cups are covered in soft rubber and are very comfortable to rest your eyes on. Four different locking positions are offered from fully retracted to fully extended. Eye relief is decent, but I couldn’t quite see the entire field wearing my regular glasses. The enlarged ocular lenses are very easy to engage with and the objective lenses are quite deeply recessed to protect the optics from rain, peripheral light and wind-borne dust. The diopter compensation is achieved by rotating a metal ring under the right ocular lens. Though it’s not lockable, it has a decent amount of resistance so won’t budge easily out of your desired position. The strap lugs are among the largest I’ve experienced on any full-size binocular, protruding quite a bit from the side of the barrels making them a bit more susceptible to getting snagged on a bush or some

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such during field use. All in all, this is a very well thought-through binocular with well above average ergonomics that make it a pleasure to hold in one’s hands. Good job Hawke. My first tests involved shining a bright light located a few meters away and examining the images captures while looking through the binocular. I detected a few minor internal reflections and quite a bit of glare around the light source. The same was true when I turned the Hawke Endurance ED on a bright sodium streetlamp after dark. From previous experience, I anticipated that such glare would also reduce the contrast a tad on daylight targets, as my later tests were to establish. Examining the exit pupils, I was relieved to see that were round with no signs of truncation, though one did reveal a small false pupil very near the true exit pupil. Testing in dull winter light which generates the worst possible lighting conditions generated good results. The field stop is very easy to see and very well defined: something I’ve grown to really appreciate. The image is nice, wide (7.6 degrees) and sharp, with good contrast though a small amount of glare reduced its punch by a notch. Colors are true to life. The sweet spot of the Hake Endurance ED 8×42 is quite large with just a little bit of peripheral softness creeping in around the edges which I didn’t find particularly distracting. Color correction is very well controlled, even off axis, where only a trace was seen on some high contrast targets. Barrell distortion was also very low on this test unit. Close focus on the Hawke Endurance ED 8×42 was found to be 1.83 m, a little better than the advertised 2 m. Tracking a small flock of Redwings flying across an open field from 10 meters to beyond 100 meters only required about a one third of an anti-clockwise turn of the focus wheel to maintain a sharp image. Viewing through the instrument gives nice, relaxed images with no blackouts or rolling ball effect encountered while panning. Color rendering is what I would describe as warm, with reds and yellows being most notably enhanced. Low light performance is decent but was not as bright as my control binocular with dielectric coatings, possibly indicating lower reflectivity aluminum or silvered (non-enhanced) roof prisms. I also detected some veiling glare while glassing a group of Carrion Crows perched high in some conifer trees against a grey overcast sky. The Hawke Endurance ED served up some very nice images of the night sky. The full Moon was nice and sharp but I could see some glare in the sky around it. Moving the bright silvery orb to the edge of the field showed up some weak lateral color and some mild field curvature. The winter showpieces of the sky including the Pleiades, the Hyades, the Perseus Double Cluster and the Sword Handle of Orion were nicely framed in this light weight 8×42. Stars remain nice tight pinpoints across about 70% of the field after which field curvature begins to distort them, but overall, I judged its edge of field performance to be good. The Hawke Endurance ED 8×42 proved to be a pleasant experience. It’s very nice to hold and everything works well. And while not a world class performer, it serves up very decent optical performance at this price point. And it’s good to know that should you encounter any hiccups; Hawke’s lifetime warranty should reassure you that they will take care of any issues you encounter.

ED Binoculars from Hawke

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The Hawke Frontier ED-X 8×42

While the Hawke Endurance ED line offers very decent optical performance, their more expensive products are a good step up in both optical and ergonomic quality. I spent a few weeks test driving their more expensive Frontier ED-X 8×42 and very much enjoyed the experience. The magnesium alloy chassis is drop dead gorgeous: small, light-weight (710 g) and covered in textured rubber for excellent gripping. I elected to test a grey colored unit, although you may also choose a more traditional green colored chassis if you prefer. The focus wheel is the dream ticket, silky smooth, accurate and precise, taking just over one full revolution anticlockwise to go from closest focus (2 m) to infinity and completely controllable with the lightest touch of one’s finger. Indeed, I would rate this particular focus wheel as one of the best in the industry! The twist up eye cups are a good step up in quality from the Endurance ED models too. They have one intermediate step between fully extended and fully retracted and rigidly lock into place with a loud clicking sound. Eye relief is adequate for eyeglass wearers too as I was able to engage with the entire field with my varifocals on. The right eye diopter is nicely grooved for easy adjustment but once set maintains its position well. Like the Endurance ED models, the strap lugs are quite large and protrude a bit more than I would like, but in my tests I didn’t encounter an issue with this. The objective lenses are nicely recessed and treated to Hawke’s hydrophobic coating causing rainwater to bead and run off the lenses during inclement periods. Of course, it goes without saying that the optics are o ring sealed and nitrogen purged making it both water and fog proof.

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The interior of the Hawke Frontier ED-X is immaculately presented, very clean and dust-free. I detected only a few very minor internal reflections when I pointed it at an intensely bright light source. There were no annoying diffraction spikes or diffused light around the same light source suggestive of the use of high-quality optical components. The daytime views through the Hawke Frontier ED-X are very impressive: bright, sharp across most of the field and I was delighted to see well-defined field stops. Chromatic aberration is pretty much non-existent in the center of the field and I was only able to see an occasional flash of lateral color near the edges when glassing the highest contrast targets. The view is good, wide (a full 8.1 degrees) and engaging thanks to excellent contrast and color rendition. Those used to using the Endurance ED models will immediately see the higher quality optics on these Frontier ED-X. The fast focus on this high-performance Hawke model makes it ideal for birding. Its excellent handling and the stable, relaxed views at 8× will bring back again and again to this delightful instrument. Any downsides? Not very much, although I did notice some issues with glare when the binocular was aimed at strongly back-lit scenes but these were few and far between. It’s obvious from a few minute’s using this instrument that you’re dealing with a high-quality instrument with excellent ergonomic features. The accessories are of very high quality too, with an excellent corduroy carry case, a test certificate and wide, neoprene neck strap and the company’s excellent no-fault lifetime warranty. I’d say you get good value for money for its £399 UK price tag. Hawke have not rested their laurels on the excellent ED-X (there is also a less expensive non-ED version known as the HD-X), but have pushed the envelope even more when they brought their Japanese-made flagship Frontier Apo models to market. Available in both 8× and 10×42 models, these pack all of the features found in the ED-X model but Hawke has also added a field-flattening optical system for even better edge of field performance. The twist up-eyecups can be removed to better clean the ocular lenses, a feature usually found on the highest quality Europeanmade instruments. As you might expect, the extra optical components add a little bit more weight to these high-performance binoculars (740 g), but to be honest, this is one of the more light-weight flat field mid-size instruments on the market. Like the other Hawke binoculars, the Frontier Apo models come with an excellent accessory pack, full test certificate and lifetime warranty. Retail prices in the UK are of the order of £599.

A Solid Performer from Viking Optical The British optics firm, Charles Frank of Glasgow, has been selling and repairing optical instruments for nearly three and a half decades. In 2016, the firm moved south to Halesworth, Suffolk, where they changed their name to Viking Optical. Recently, the company launched an exciting range of affordable roof prism binoculars featuring a number of impressive optical features exhibited in their Kestrel,

A Solid Performer from Viking Optical

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Merlin and Peregrine (all keen eyed raptors) binoculars. Three models are offered in 8×32, 8×42 and 10×42 configurations, and all feature fully multi-coated optics, dielectrically coated and phase corrected BaK4 prisms and objectives containing ED glass elements in a fully waterproof housing. Although all these models are assembled in China, I reasoned that their acquired knowledge in repairing binoculars over many years would put them in a strong position to offer a quality experience, so I pulled the plug and decided to order up the 8×42 Kestrel model for optical testing and evaluation. The binocular was ordered up from Amazon and the instrument arrived in the evening of the following day. I was immediately impressed with the packaging of the Kestrel. Instead of the regular color-saturated cardboard box that usually attends many of the binoculars that have passed through these parts, I received a very fetching presentation box with the phrase “Extend Your Horizons” printed on top. After removing an outer slip case, the binocular and accessories were carefully packaged away inside.

The Viking Kestrel ED 8×42

The package contained the binocular inside its soft padded case, a high-quality padded neck strap and one page instruction sheet with details of the warranty. The company states that the binocular went through several stages of testing before the instrument was finally packaged up for distribution. Both the ocular and objective lenses came with standard soft rubber caps which can be permanently affixed to the binocular. I was half expecting a lens cleaning cloth but none was provided.

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The binocular has a very attractive appearance, with the optics housed inside a strong polycarbonate body overlaid by an anthracite-colored, textured rubber armoring. While I’ve used binoculars with magnesium alloy bodies before, I’ve not noticed any particular advantage of using metal bodies over their synthetic polymer counterparts, except perhaps to shave off some excess weight. But at 692  g, this binocular is not exactly heavy. Indeed, surveying the market in 8×42 roof prism binoculars quickly reveals that the weight of the Kestrel falls into the median in the range for instruments of this specification. The fetching anthracite color of the binocular is beautifully complemented by the sky-blue logo of the company and its ED billing inlaid on the top surface of the instrument. I’m not normally taken much aback by the cosmetic appearance of a binocular, but I must admit to really liking the color scheme of this instrument! The binocular has a single centrally placed hinge that is reassuringly rigid. Once adjusted to get your particular interpupillary distance (IPD) right, it stays in place even when taken out of and placed back inside of its padded case. Both the focus wheel and right eye diopter are constructed from metal and coarsely stippled for maximum grip. The twist-up eye cups are of very high quality, rubber over metal that offer 3 positions. With a very generous eye relief of 17.5 mm (measured), they afford very comfortable viewing for those who wear eyeglasses and those who don’t. Most importantly, when clicked into place they hold their position very solidly, even after an undue amount of pressure is applied. The underside of the body has two small thumb rests which allow your fingers to naturally gravitate towards when handling in the field. Overall, I found the Kestrel to be have very nice ergonomics. The focus wheel moves with what I would describe as slow-to-standard progression. There is a little bit of play in it which can sometimes result in over- or under- focusing, especially when imaging a fast-moving object, but overall, I felt it was perfectly adequate for most purposes one would use a binocular like this for. The wheel moves through 1.5 revolutions from its close focus to beyond infinity. Having a little extra focus travel beyond the infinity setting may not have any immediate advantages, but I’ve found that it is quite important when attempting to clean up the image at the periphery of the field. In other words, having a slightly longer focus travel can help alleviate some of the off-axis field curvature found in most any binocular image. The objective lenses on the Kestrel have very nice and evenly applied anti-­ reflection coatings. What’s more, they are very deeply recessed – exceptionally so, I’d say. I measured them at a whopping 10 mm – significantly deeper than any other binocular I have encountered. This affords exceptional protection against rain, and wind-borne dust and will also attenuate the buildup of contrast-robbing dew. All in all, I was well pleased with the ergonomics and physical presentation of the Kestrel, but all of that counts for naught if the optics are not up to scratch. Mounting the binocular on a tripod is easy to do by unscrewing the stalk at the front end of the bridge, between the two barrels, and which enabled me to test the collimation of the instrument by observing well defined targets on a hillside a few miles distant, looking for both horizontal and vertical asymmetries in the images

A Solid Performer from Viking Optical

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presented in both optical tube assemblies. To my relief, the Kestrel showed no misalignment issues. No roof prism binocular, no matter how well made, can perfectly stave off unwanted reflections, diffraction artifacts and diffused light when a very strong light source is directed inside the instrument Setting up my standard iphone torch light test, I was impressed with the results I obtained with the Kestrel, which served up an exceptionally clean image, with very low unwanted reflections and an almost imperceptible diffraction spike. Furthermore, diffused light was pretty much non-­ existent. Further testing on a sodium street light confirmed the same results; the view through the Kestrel had well-nigh perfect results with no annoying internal reflections, zero diffused light and no diffraction spikes! I did however detect rather strong off-axis flaring with the Kestrel, which was more pronounced than in my control binoculars, as evidenced by placing the streetlight just outside the field stop of the instrument. Overall, though, I was very pleased with the outcome of these stray light tests, which suggested that the Kestrel would likely deliver exceptionally punchy images, rich in contrast during normal daylight use. My first day of testing took place on an overcast June day in 2020. Examining some tree trunks a few tens of yards distant showed a very wide and sharp, vibrant image. Color tone was what I would describe as neutral. Within its large sweet spot, I judged the image sharpness to be very good. Examining the summit of a nearby hill against a bright overcast sky also revealed that the Kestrel was well corrected for chromatic aberration as judged by the absence of a very faint sliver of blue fringing at the boundary between the summit and the background sky. That said, it soon became clear to me that the Kestrel was showing some glare when pointing the instrument near a strongly backlit scene but much of it could be removed by simply placing my hand over the objectives. The flaring was also reduced by observing through an open or closed window under a roof but always reappeared once I re-emerged into the out of doors. After a day of heavy rain, the clouds cleared off in the evening, leaving a tranquil blue sky. It was the perfect opportunity to go for a long walk around the picturesque Culcreuch Castle Estate with the Viking Kestrel 8×42 ED. The instrument feels very solid in my hands and its fine mechanics work flawlessly. The quality padded neck strap with the company’s fetching color logo proved very comfortable to use. I stopped to say hello to a pair of Mute Swans and their family of five cygnets at Culcreuch Pond. The binocular served up beautiful, pin-sharp, views of the pure white plumage of the adults wonderfully contrasted with their rusty orange beaks and jet-black foreheads. The cygnets had almost lost their fluffy down feathers by now and had developed their attractive tawny drapery, which stood out well against the sullen waters beneath them. And though the surface of the pond dappled in strong reflected sunlight, the binocular served up great images with good contrast and no annoying reflections. Ambling up the path a little further, I enjoyed a fascinating 15-minute excursion watching a group of Swallows perform their incredible feats of aeronautics

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(far more advanced than any human made flying machine) swooping and gliding with great speed and agility, gorging on low flying insects along a large grassy lawn immediately in front of the castle. The Kestrel proved to be a great instrument to follow them, with its very large (8.1 degrees) and well corrected field of view. Their prominent forked tails, iridescent blue-black upper body and almost comical, chocolate-­brown faces could easily be made out as they flitted across the field of view. A lady out walking her dog, obviously curious about my glassing, stopped to tell me that a few big storms had threatened these migratory birds earlier in the year, reducing the numbers reaching our shores from Africa. It put a big smile on her face to see that it was business as usual for these noisy summer visitors! These experiences convinced me that the Viking Kestrel 8×42 will make a very decent birding binocular with its good contrast, sharpness and color correction, not to mention its super-comfortable twist-up eye cups, generous exit pupil size and smooth focusing wheel. As I continued to walk, I enjoyed glassing the intense color of mature green leaves drenched with life-giving rains that made them glisten intensely in the early evening sunshine. I almost lost myself observing the intricately textured bark high up in their canopies against a gorgeous blue sky beyond. That said I must also report that there is very mild pincushion distortion at the edge of the field but certainly not enough to cause any alarm.

Using the Sky as a Binocular Testing Ground After sunset I ventured out again to catch a nearly full Moon skirting low in the south-southeast at about 11 pm local time. To get a good unobstructed view I had to take a walk about halfway up Culcreuch Castle Road. But it was worth it. The almost full Moon in all its glory hovered just above the tree line beyond a gently sloping hill, its low altitude imparting a yellowish cast to its normal pale silver countenance. The image served up in the Kestrel was gorgeous, pin-sharp across almost the entire field, with beautiful contrast and nary a sign of any internal reflections. This will make an awesome Moon glass! As usual, I noted that the Moon remained sharper when glassed horizontally than vertically, again very normal behavior for a binocular. Round about a quarter to local midnight, the sky had gotten sufficiently dark to make out the familiar asterism of the Plough high in the northwest. This afforded a perfect opportunity to estimate the size of the field of view. Well, I was able to hold Phecda and Merak in the same binocular field, which I estimated to be 7.9 angular degrees apart, with a tiny sliver of open sky available before it reached the field stop. Thus, I was confident that the ~8.0-degree field I measured was close enough to the quoted 8.1 figure stated in its official specifications. What is more, I glassed the bright orange star, Arcturus, high in the west-­ southwest, carefully examining the sharpness of the stellar image as it moved from

A Flat Field ED Binocular from Celestron

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the center of the field all the way to the field stop. The results were good here too; Arcturus remained nice and pin sharp across most of the field with only the outer 15% showing significant distortion, but there was no ballooning of the star like some inferior models I’ve glassed with in the past. That said, I was still able to play with the focus a little to tidy the image up somewhat at the edge of the field showing that the predominant (but not the only) off-axis aberration was field curvature. All in all, I came away convinced that this would make an excellent star gazing glass. I can’t wait to use it later in the summer when truly dark stars return to our shores. There are good reasons why the 8×42 configuration is considered the darling glass for birders, hunters and general nature observers. The extreme comfort with which it meets with your eyes, moderate weight and great low light performance are just a few reasons why they have proven so popular. The Viking Kestrel 8×42 is packed full of hi-tech optical features and has very solid mechanics that will ensure it will serve you well for many years. Other testers were pretty much unanimous in their praise of this extraordinary binocular, and for a retail price of just over £200 UK, I feel it represents good value for money. Indeed, one reviewer thought that the Kestrels were the real winners from the entire Viking Optical range, especially when you consider bang for buck. While we’re discussing Viking Optical products, the reader may be interested that the company market a great variety of binoculars that are tried and trusted by UK birders and nature enthusiasts; something for everyone indeed. Interested folk should check out their higher-performance models such as the Viking Merlin, Peregrine and Osprey binocular lines.

A Flat Field ED Binocular from Celestron Celestron is normally a name you’d associate with astronomy, but in recent years they’ve entered the mid-priced sports optics market with a number of new models designed for the outdoor enthusiast. We’ve already discussed the very economically priced Trailseeker models in the previous chapter, but shortly after these models hit the market Celestron introduced a souped up version of this instrument with the launch of the Trailseeker ED series of compact and mid-size binoculars with improved optical performance. But what really piqued my attention was their launch of a new high-performance ED instrument with flat field technology; enter the Celestron Regal ED series.

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The Celestron Regal ED 8×42

You see, there’s a quiet revolution taking place in high quality sports optics. Over the last decade, Chinese optics houses are producing instruments of amazing quality, packed full of features that up to very recently would have been unthinkable. This is not born of idle speculation but from solid and extensive experience of many instruments made in China and now marketed extensively in western markets. I’ve already showcased a number of instruments produced by Svbony, Vortex, GPO, Opticron and Nikon to name just a few, that have gone well above and beyond the call of duty, producing very high-quality instruments that offer both excellent images and solid ergonomics in packages consumers could only dream of a few short years ago. The instrument I will showcase in this blog is the Celestron Regal ED 8×42, the new flagship, full-sized binocular from the well-known telescope manufacturer. The instrument was kindly lent to me by fellow binocular enthusiast, Gary, from Northern Ireland. He was keen for me to put it through its paces and to see what I thought of it. I’m delighted to reveal that I was very impressed with the instrument and would recommend it wholeheartedly to the community. For more details though, read on. Celestron has been turning heads for a while now, bringing a good range of binoculars to the low and mid-priced market. The Nature DX and DX ED ranges are very good entry-level instruments for those who wish to cut their teeth in quality binocular optics, featuring fully multicoated components, phase corrected roof prisms in lightweight, weatherproof housings. Moving up to the Traliseeker models, we see Celestron offering durable Magnesium alloy chassis, dielectric coatings and

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higher quality optical components, delivering brighter and sharper images. The next step in the intelligent design of the Celestron binocular is embodied in the Trailseeker ED range, which added extra low dispersion glass for sharper, higher contrast images. Collectively, these instruments have delighted birders, hunters and general outdoor enthusiasts alike and helped the hobby grow in ways unthinkable to the elitist attitude of top European optics houses, creating feverish competition between manufacturers to deliver the best bang for buck in a rapidly growing and evolving market. Now Celestron has gone one step further still, introducing flat field optical technology into their new flagship binocular models in the form of the Regal ED 8× and 10×42. The 8×42 binocular arrived brand new, as Gary had conveniently arranged for it to be sent to me first before shipping on to him at the conclusion of my tests. The instrument arrived inside an attractively presented black and orange box – the longstanding trade colors of Celestron. Upon opening the box, I found a beautifully designed clamshell case safely storing the instrument away inside. All the usual accessories were there: the tethered rubber objective covers, a high-quality rain guard, neoprene neck strap and binocular harness, microfiber cloth and instruction manual. Holding the instrument in my hands for the first time, I was immediately taken by the heft of it. This is one chunky binocular! Weighing in at over 800 g I was immediately struck by its attractive black rubber armoring and fetching orange touches. The heft of a binocular like this shouldn’t really surprise anyone. All those hi-tech optical components add to the weight of the instrument and, as such, is no different to anything found from the top-tier of European alpha binoculars. Irrespective of how their weight is re-distributed under the bonnet, they’re all bricks in the end. Heavy. The oversized focus wheel moves with buttery smoothness, with no annoying free play or backlash. Just short of two full rotations anti-clockwise brings you from closest focus to infinity and a little bit beyond. Tension is excellent. I was able to move it perfectly well with my pinkie! The nicely machined multi-stage, twist up eye cups are clad in soft rubber and click rigidly into place. I noted that they were not quite as firm as those I experienced on the Trailseeker model, but still presented no issues in field use. The eyecups are very comfortable, with no eyestrain experienced even after using it for a couple of hours in the field. The right eye diopter located under the ocular lens is larger than normal, and moves smoothly with a good degree of friction ensuring that it stays in place with no issues. The large ocular field lenses are easy to engage with and I found no real trouble centering my eyes on the large (5.25 mm) exit pupil. The fully broadband multicoated objectives are nicely recessed, protecting them from rain, dust and peripheral light sources. Eye relief is very generous. Though I don’t observe with glasses on, I had no trouble seeing the entire field when I donned by varifocals, with the eye cups fully retracted. The underside of the binocular has some shallow thumb indents. I found these convenient to use but it’s not something I look for specifically when shopping for an instrument. The textured rubber armoring affords excellent griping in the hands and though I personally have a preference for a slightly shorter bridge where

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I can better wrap my fingers round the chassis, I was quickly able to find a nice stable positioning with my hands, allowing me to enjoy the views. Clearly Celestron have done their homework in delivering a very solidly made instrument that looks and feels like a quality act. Top marks awarded for ergonomics! And I’m delighted to disclose that the optics too impressed me! I began, as ever, directing a bright beam of light into the binocular and examining the images garnered from across my living room. These tests revealed very good results. There were no diffraction spikes, only the merest traces of weak internal reflections and no contrast robbing diffused light around the beam, all collectively indicative of high-quality optical components. My next test involved examining the exit pupils. Both presented as almost perfectly round with very little in the way truncation, but I did record some stray light immediately outside each pupil. As soon as I brought the binocular to my eyes, and even before I had made the diopter adjustment, the image served up by the Celestron Regal ED was really impressive. That’s a sure sign of excellent optics. The image is very sharp across most of the field, with excellent contrast, casting a distinctly warm color balance. Chromatic aberration is very well controlled in the center of the image, with only a trace of lateral color appearing in the outer part of the field on the highest contrast targets. Seeing the hard field stops certainly enhanced the degree of immersivity of the images. Testing the field flatness, I was pleased to see very good control of barrel distortion. Drainpipes and telephone poles maintained their straightness even when placed near the edge of the field. Indeed, it showed up the distinct barrel distortion in my own full-sized roof prism binocular all too easily. I detected some slight blurring at the edge of the field during my daylight testing but wasn’t sure of its nature until I employed the instrument under the stars and a bright, late December Moon. By defocusing the bright star Procyon with the right eye diopter, I was able to confirm excellent collimation. Turning the binocular on a bright gibbous Moon showed some very minor internal reflections. The Moon looked razor sharp within its generously wide sweet spot, with excellent contrast and control of chromatic aberration, but when I moved the silvery orb to the edge of the field, I could see that the last 10% or so of the field produced a blurred image with some lateral colour – blue and yellow for the most part. I attempted to refocus the lunar image but was unsuccessful in doing so. This suggested the presence of astigmatism and/or coma as opposed to field curvature, which is easily focused out in contrast. Turning to some bright stellar luminaries of the winter sky, I was impressed how well they maintained their pinpoint sharpness across most of the field, showing some elongation near the field stops. Turning back once again to daylight tests conducted during some dull, overcast early January days, the Regal ED showed excellent control of glare, for the most part, but some did creep in when the binocular was pointed to targets in the general direction of the Sun. Veiling glare, on the whole, was also very well suppressed in this instrument too. Scanning a long stretch of conifer trees near one of my local

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patches did throw up some blackouts and some mild manifestations of the rolling ball effect, but it was far less severe than what I had encountered with a Swarovski EL 8.5×42 and a Nikon Monarch HG 8×30 in comparison. Comparing the images in the Regal ED to my control binocular – the Svbony SV 202 ED 8×42  – during dull overcast conditions, I concluded that the latter was slightly brighter, a consequence I suppose of it having a simpler optical design, without using field flattening lenses. More optical components usually result in lower overall light transmission. Close focus was measured to be just over 2 meters, a bit longer than the advertised value of 1.5 m, but not an issue for me. I enjoyed some stargazing vigils with the Celestron Regal ED 8×42. Its very wide sweet spot – covering about 85% of the field – made sweeping the winter Milky Way through Perseus and Cassiopeia a very pleasant affair. I enjoyed great views of the Swordhandle of Orion and the brilliant white Belt Stars. The instrument effortlessly swept up the trio of Messier open clusters through Auriga and made easy pickings of M35 in Gemini. The Pleiads were sparkling jewels in this instrument and below them, the magnificent Hyades produced some very memorable views. Mars was an intensely bright beacon high in the winter sky, its beautiful ochre tints standing out well against a jet-black sky hinterland. This will make a great binocular for astronomical viewing, but its significant heft will probably limit hand-held use to a few minutes at a time. That said, it’s easily mounted on a lightweight monopod if you’re after rock steady views of the heavens. Is the Regal ED for you? Well, that depends on how well you respond to the effects of the field flattening lenses built into the instrument. I suspect that most people will find these new Celestron binoculars to be great. For me though, I have gradually come to realize that I prefer non-field flattened optics. I prefer the more relaxed views of daytime objects without any blackout issues, even if that means sacrificing some field of view and the effects of barrel and pincushion distortion. This is definitely a binocular to try before you buy, if at all possible. But I can wholeheartedly recommend it to the binocular enthusiast looking for great optical and ergonomic performance. Celestron has really come a long way introducing these new high-performance instruments. Where next Columbus?

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A Flat-Field Binocular from Athlon

The Athlon Cronus 8.5×42. (Image Credit: David Laughlin)

US-based Atlhon Optics, whose headquarters are situated in Olathe, Kansas, offer a number of full-size binoculars packed full of sophisticated features but at process that won’t break the bank. Just like the Celestron Regal ED featured above, Athlon also sell binoculars with field flattening optics. Take for example the Athlon Cronus 8.5×42. David Laughlin from Virginia, USA, kindly provided his opinion of this instrument. “For its size and configuration my 8.5×42 Athlon Cronus presents the most pleasing and sharp views for me. They do what I expect a binocular to do. The ED glass and FMC coatings make for very bright crystal-clear views. At night it is obvious that they let in more light than my other ×42’s, including my 10×42 Oberwerk Sport ED’s and my Canon 10×42L’s. The image is flat to the edge and stars are pinpoint to the field stop. The main visual values are light, clarity, and no distortion of any kind. There are things not to like or to rectify. These I have been mentioned in the thread. (1) Weight due to hard plastic casing and perhaps more lenses and field flatteners (2) The focuser is stiff (3) The ER is so long that getting the exit pupil just right can be problematic. I rectified this with new rubber eyecups fit over the originals. It works perfectly for me with the twist up eyepieces set at two stops out. While it is not as versatile in weight and mechanical performance as many other binoculars, for casual viewing from one’s home or from a lounger the optical quality of the views are hard to beat. The slow focuser is an impediment to birding and watching moving objects. The weight means other choices are better when hiking or on outings. But for anything 8× or ×42 that I

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own, the Athlons render the sharpest and brightest views across the entire field. At night the non-IS views of the Athlons beat the non-­IS views of my 10×42L Canon. It’s a great nighttime binocular. In my opinion, the Athlon Cronae could also be described as discount Mavens. Not quite as good as the Mavens but almost. And at full price they are 1/3 cheaper than Mavens. Athlons are just not as widely known and are under-appreciated in my view. They have a big following amongst US hunters, especially their rifle scopes. Astronomy and birding are not their key market.” The Athlon Cronus retails for about $270 – that’s a lot of bang for your buck.

A Sophisticated 10×42 from Vanguard Vanguard is an international optics company founded in 1986 with over 1000 employees worldwide. As well as binoculars and telescopes, they have also marketed high quality accessories for the sports optics industry. With a manufacturing and design headquarters in Myanmar, they offer an extensive range of binoculars from entry-level to upper mid-priced models. In this review, I’ll be discussing my experiences with an Endeavour ED II 10×42 binocular. This is a second-generation ED binocular, bridging their simpler ED and more sophisticated ED IV models. Vanguard state that the ED glass elements used in their objectives are sourced from Hoya (Japan), but are assembled entirely in Myanmar, before being distributed to stores across the world.

The Vanguard Endeavor ED II 10×42

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I purchased the binocular with my own funds for £280 delivered to my door. The instrument arrived double boxed and came in a very attractive white storage box containing the binocular, a very nicely designed zipped closed logoed carry case, a padded neck strap, rubber ocular and objective lens covers, which can be tethered to the binocular, a lens cleaning cloth and an instruction sheet in many languages. The Vanguard ED II 10×42 is an impressive looking instrument, sporting a high-­ quality Magnesium alloy open hinge design, with a black pebbled rubber overcoat that has a texture more akin to bonded leather than the usual rubber-looking substrate offerings on most other models I’ve sampled. Weighing it at 770 g, it is quite hefty as 10×42 binoculars go, but still nowhere near the 850 g weight of some of ultra-premium models now on the market. The instrument feels very solid and secure in the hand. On its underside, two thumb indents suggest a place for you to properly hand old and balance the binocular. The instrument states, “made in Myanmar” and has a serial number to help identify the batch and date of production. The objective lenses have immaculately applied anti-reflection coatings and are very deeply recessed to cut down on stray light, dust and rain. The binocular has a number of notable features compared with many mid-priced instruments that I have tested in the past. For one thing, the right eye diopter is lockable. You simply push the ring up, rotate it to your desired position and then push it down to lock. It works quite well but I did notice a bit of play in it. The ring itself wobbles when a bit of force is applied and to be honest, I would have been perfectly happy with a regular non-lockable diopter ring if it offers a bit more rigidity. The more advanced ED IV models from Vanguard offer a better solution in this regard. The central focus wheel is covered in a highly texturized rubber for excellent grip. Rotation is exceptionally smooth, taking just over one revolution of the wheel to go from one extreme of focus to the other. It is also remarkably fast, taking just three quarters of a revolution to sharply focus on the vast majority of objects. This makes it especially useful for birding, where rapid focus changes can be important, but I found it to be, well, a little too fast. You can easily overshoot the focus wheel if you’re not used to it, so this could be a bit off-putting for some users. Personally, I would have been happier with a slightly slower focus but having said that, it’s all about getting used to the binocular; so, in and of itself, a super-fast focuser is certainly not a deal breaker. The twist-up eye cups are metal-over-rubber and have two intermediate positions. Fully extended, they hold their positions very well indeed. The generous eye relief of 19  mm makes it very comfortable to use with glasses (tested by yours truly), where the entire field can be reliably imaged. Another nice touch about these eye cups is that they can be unscrewed when they wear down or break. Vanguard will be happy to send you replacement cups should you run into a spot of difficulty. The binocular can also be mounted to a tripod or monopod for ultra-stable viewing. Simply unscrew the V-logoed screw on the front of the bridge and you’re in business. Conducting the flashlight test on the Vanguard showed a good clean image; internal reflections were very minimal with no discernible diffused light indicative of good, homogeneous glass through the optical train. It did show a rather

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prominent diffraction spike though that was also observed at night when I turned the instrument on a bright sodium street light. Conducting further daylight tests revealed a very sharp image with lots of contrast and excellent control of glare. Indeed, the Vanguard Endeavor ED II 10×42 showed better control of veiling glare than my control binocular. The view is good and wide for a 10×42 instrument – 6.5 angular degrees. What’s more, the Vanguard enjoys a very large sweet spot. Indeed, it’s edge of field correction is excellent, especially considering its modest retail price. There is very mild pincushion distortion near the field stops. Colors are naturally presented and chromatic aberration is, to all intents and purposes, non existent. Indeed, I could only detect a trace of lateral color at the edge of the field. All in all, the optics in this binocular are well above average, a fact that I was able to confirm by borrowing a first generation Swarovski EL Range 10×42 from a fellow villager. To my eyes, the views were very comparable in bright sunny conditions with the Vanguard having a slightly wider field of view. Only when the light began to fade late on that summer evening did I begin to notice the Swarovski beginning to pull ahead. At dusk, near local midnight here in Scotland, the greater light transmission of the EL Range was obvious, with tree branches located at a distance of 50 yards or so away being more easily seen than with the Vanguard. This is consistent with an allbinos review conducted on the Vanguard Endeavor ED II 10×42, which revealed a light transmission of only 80%. Another low light test using my control binocular (a Series 5 Barr & Stroud 8×42) also showed a significantly brighter image than the Vanguard but this could well be attributed to its larger exit pupil (5.25 mm versus 4.2 mm) kicking in during these low light conditions. The close focus on the Vanguard Endeavor ED II is very noteworthy in that it focuses down to about 1.5 meters. I could sharply focus my walking shoes, which is more than I can say for many other 10×42s I have had the pleasure of using. Depth of focus is quite shallow though – an expected result given its 10× magnification. Focusing is super-fast on this unit, but I was slightly anxious about turning the focus wheel near the end of its travel. A tyro could easily turn the wheel too far and so damage the focuser. The lockable diopter ring worked well in all situations. It remains tightly in place, so no worries there. Because of the super-fast focus wheel, I deemed it expedient to set the diopter setting while the binocular was stably mounted on a tripod. After all, you need a stable view in order to achieve optimal image sharpness in both barrels. The open bridge design of the Vanguard makes it very easy to handle, even with one hand. You can wrap your fingers around the barrels of the binocular which allows the user to get a slightly more stable view at 10×. The padded neck strap accompanying the Vanguard Endeavor ED II is of good quality but is a bit too long for my liking. Indeed, I often thought about attaching another shorter strap while making my tests. I do love the padded case supplied with the Vanguard. With its eye-catching color logo, padded interior and its ability to be zipped closed, I think it’s one of the most thoughtfully designed binocular cases I’ve personally encountered. A very nice touch!

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The Vanguard Endeavor ED II 10×42 offers a lot of bang for the buck. Optically, it serves up very nice images indeed and will hold its own against instruments costing far more. Indeed, my main take home point about this instrument is that as one invests in more expensive models, it’s mainly the mechanical and not the optical properties of such an instrument that one is buying into. More expensive binoculars will have greater light transmission (of the order of 90%) but those advantages can really only be seen at dawn or dusk. So if you do all of your glassing in broad daylight, that light transmission advantage will be of little importance to you. Just something to bear in mind. I also get the impression that Vanguard care about their customer service and one can email an employee of the company if you encounter any problems with your binocular. If you’re in the market for a sensibly priced instrument in this aperture class that will live up to the rigors of life in the great outdoors, then I would strongly recommend it. You’re not likely to get much more for an investment under £300 UK. If The Vanguard Endeavor ED II doesn’t satisfy, the Vanguard also market an even better model, the Endeavor ED IV. Outwardly it’s very similar to the ED II but the diopter adjustment is re-located to the focus wheel: pull the wheel out for adjusting to your desired setting and push down again to lock. The EDIV also features improved optics over the ED II, with SK-15 prisms coupled to Hoya premium ED glass. The coatings are also a tad better on the EDIV compared with the EDII.

A Wide Angle Binocular from Kowa

The Kowa BD II 8×42. (Image Credit: Kowa Sports Optics)

The Japanese sports optics company, Kowa, are no strangers to the high-quality binocular market. Their new BD II XD series of wide-angle binoculars was

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introduced in 2019 and generated quite a bit of attention from birders, hunters and outdoor enthusiasts alike. Initially these instruments were manufactured in Japan, but production recently switched to China. The series consists of three 32 mm models with magnifications of 6.5s, 8× and 10×. There are also two 42  mm models delivering powers of 8× and 10×. One of the most popular models is the 8×42. This is a high-quality binocular designed for birding, wildlife observation, and other outdoor activities. It features a durable and lightweight magnesium alloy body (640 g) with a green rubberized coating for a secure grip. The oversized central focus wheel is silky smooth and backlash free and the twist up eye cups offer an exceptional 19 mm of eye relief. The binocular is also waterproof and fog proof, ensuring reliable performance in various weather conditions. One of the stand-out features of the Kowa BD II XD 8×42 binocular is its advanced optical system. The binocular uses XD (Extra-low Dispersion) lenses, which minimize chromatic aberration and deliver sharp, clear images with high contrast and accurate color reproduction. The lenses are also fully multi-coated, which helps to maximize light transmission and minimize reflections, resulting in bright and clear images even in low light conditions. The binocular delivers a bright, sharp high-contrast image in a very large (8.2 degrees) field of view. Close focus distance is reportedly excellent – 1.5 m – allowing you to observe nearby objects with clarity. The binocular also has a comfortable eye relief of 17  mm, making it easy to use even for those wearing eyeglasses. Overall, the Kowa BD II XD 8×42 binocular is a high-performance binocular that provides excellent image quality and rugged durability. Small wonder it’s a popular choice among birdwatchers, nature enthusiasts, and outdoor adventurers. The Kowa BDII 8× and 10×42 retail for about $480.

An Ergonomic Delight from Barr & Stroud Want a very nicely performing binocular with a wide field of view for birding, stargazing or just enjoying the great outdoors? The Barr & Stroud (B & S) Series 5 8×42 ED may interest you. I’ve already showcased the open bridge Series 8, 8×42 from the same company, but these Series 5s also have a nice touch of class about them. There are two incarnations of this binocular, a non-ED and a model with ED glass, which are otherwise identical. Here we’ll go over some of my findings with the ED model. The instrument feels very solid in my medium sized hands. The magnesium alloy chassis and not overly thick green rubber overcoat helps keep the weight down. Indeed, I measured its weight at 710 g, as opposed to just 690 g for its non-ED counterpart. That made sense to me as ED glass elements tend to be a little heavier than regular crown and flint glass. As mentioned above, the rubber-clad metal eye cups twist up with two intermediary positions. They were easy to extend and held their positions securely, with very little wiggle room. Eye relief is a very generous 17.2 mm, large enough to see nearly the entire field with my eyeglasses on. The centrally placed focus wheel is large, very nicely tensioned and very smooth to operate, both clockwise and anti-clockwise. If anything, I thought it was a shade

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over tight compared to its non-ED counterpart but to be fair, all focusers need a bit of breaking in time to get them moving as smoothly as possible. That said, I have spoken before about the care B & S put into their focusers. They are much better tuned than the majority of other binoculars I’ve tested in this price range. Taking just over two full revolutions to go from one extreme of travel to the other, I would describe it as being intermediate between the super-fast focusers birders seek after, and the slower focusers hunters prefer.

The Barr & Stroud Series 5 8×42 ED

The metal diopter ring is located under the right ocular, and while not lockable, is quite stiff and easy to adjust. Moreover, it stays in position very well. Handling this binocular is a real joy. While not the grippiest substrate I’ve encountered, the green rubber armoring provides a very adequate level of friction with your hands. There are no thumb indentations on the belly of this binocular but I’ve never really found them to be that advantageous to the overall ergonomics compared with several other binoculars that did have them. The rubber armoring is a little thinner than other models, such as the Nikon Prostaff and Monarch 5 & 7 lines, but this does cut down the weight of the binocular, which makes transporting it that little bit easier. The Series 5 ED binocular I received did not have the ED labelling under the left ocular, as I was expecting from the images I’d seen on a few retailers’ websites. Instead, this model presents the ED moniker on the focus wheel, which might possibly indicate that this instrument was manufactured more recently.

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I’ve always been more than satisfied with the padded neck strap accompanying the more expensive B & S binoculars. It’s very comfortable to wear around your neck without much in the way of chafing after a long walk on level ground on a hot summer day. The hard clam shell case is another great accessory. It zips closed and there is a little storage area inside to carry a lens cloth or a sachet of silica gel desiccant to keep the interior as dry as possible when not in active use. Examining the exit pupils on the binocular showed nice circular openings, with a nice rim of dark around them. All in all, I was very pleased with the overall fit and feel of the Series 5 ED 8×42. Elegant and understated, it has very nice mechanics that should hold up in field use for a long time to come. I’ve noticed that many binocular reviews published in birding magazines seem a tad over generic. Indeed, in many cases one could simply remove the name of one binocular and replace it with another, and hardly anyone would be the wiser. And in some reviews, I’ve come across, the sense I get is that the writing is so contrived as to be almost fictional. Quite often, reviewers report ‘peripheral softness’ in the outer part of the field or some such. Others report that the field is either too restrictive or wide and expansive. And still others report some drop off in illumination towards the edge of the field. The trouble with this kind of reporting is that it is rather too subjective. Many birders might be interested to learn that one can get a much better handle on the extent of those properties simply by looking at the Moon in the sky or a bright star field. For example, one can use a pair of stars of known angular separation to accurately measure the field of view of any binocular. Off-axis aberrations can also be more accurately ascertained by moving a bright star from the center to the edge of the field and noting how and where the stellar images begin to morph significantly. Furthermore, moving the Moon to the outer edge of the field will easily show reduced brightness if indeed, it exists at all. What’s more, the Moon can also be used to differentiate non-ED more easily from ED binoculars at the same power by looking at the extent of fringing observed on the lunar limb. So how did the Series 5 8×42 ED fare under the starry heaven? How did it look on the Moon? After a very overcast day on August 31 2021, the clouds dispersed very late in the evening, leaving a clear and tranquil sky to verify the many properties of a binocular that can be ascertained simply by examining the images of bright stars in a binocular field. Assisting me this evening was Joe, who kindly gave me about 90 min of his time testing out several binoculars in comparison to the Barr & Stroud Series 5 8×42 ED. Starting shortly after midnight, we continued our tests on various objects until about 1:30 am, September 1. The first thing we verified was the size of the field. As stated before, if you happen to know the angular separation of two bright stars in the sky, you can use that information to measure field size. As usual, I chose the two stars in the Ploughshare asterism in Ursa Major. We were just about able to fit Phecda and Merak into the field of view of the binocular. These are separated by 7° 54′ or 7.9 angular degrees, so I’m confident that the stated field size (8.1 angular degrees) for this binocular is

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fairly accurate. As an additional control, we employed the Nikon Monarch HG 8×30, with an advertised field of view of 8.3 angular degrees, to show that it too was able to frame these two stars but with a little more room to spare. Next we tested how well corrected the field was in both the Barr & Stroud Series 5 ED and the Nikon Monarch HG 8×30. Focusing on bright yellow Capella, now low down in the northeast, we took our turns moving the star from the center to the edge of the fields in both binoculars, making mental notes of the experience and later committing those notes to pen and paper. Here’s what we found: first off, the Nikon Monarch HG, despite having a field flattener built-in, did not have an entirely flat field. Furthermore, its lateral flatness was noticeably superior to its vertical flatness. To make that even clearer, side-to-side flatness was much better than up-and-­ down flatness. Furthermore, we observed the same phenomenon in several other binoculars including the Barr & Stroud Series 5 non-ED, the Celestron Trailseeker 8×32, a Carson VP 10×42 and a Leica Ultravid 8×20. This asymmetry is a very real phenomenon. The little Leica Ultravid 8×20 exhibited by far the flattest, best corrected field of all the instruments tested. The next best corrected field was the Nikon Monarch HG 8×30, where stars began to morph in shape at about 75% out from the center, getting gradually worse as it reached the field stop. The Barr & Stroud Series 5s were pretty much identical, with distortions occurring from about 70% out from the center. What is more, apart from the extreme top and bottom of the binocular field, both Barr & Stroud Series 5s offered up acceptably small stellar images over pretty much the rest of the field, making them excellent star gazing binoculars. We were both quite shocked to see the Nikon Monarch HG behave in this way, as our daylight tests didn’t show this field curvature nearly as acutely as the star tests did. All we could say is that the Monarch HG had a flatter field than the Barr & Stroud Series 5s. By 1.00 am local time, a last quarter Moon was rising over the hills to the northeast, and we were able to test for chromatic aberration in both the Series 5 ED and non-ED binoculars. We both detected a small amount of secondary spectrum on the lunar limb in the non­ED which was all but absent in the ED, in full accordance with our expectations. Finally, by moving the Moon laterally off axis, from the center to the edges of the field, we noted how the lunar maria darkened a little near the field stop showing clear evidence of edge of field illumination drop off. That said, the same phenomenon was noted with the Monarch HG and the Leica Ultravid, although to a lesser extent. While certainly not in the same league as an alpha binocular, it does offer up very satisfying optics and ergonomics punching well above its modest price tag. I would unhesitatingly recommend this binocular as a very capable general use binocular that will sate the demands of the majority of birders, nature watchers and stargazers alike. It just does many things well and has a very wide and well corrected field. With a retail price of £219 (UK) and 10-year warranty, I’d say that’s one heck of a bargain.

Sweet Deals from Zeiss: The Terra ED 42 mm Binoculars

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Sweet Deals from Zeiss: The Terra ED 42 mm Binoculars Up to about 2005, the sports optics giants, Zeiss, produced all of their products in Germany. Between 2005 and 2012, Zeiss started up a factory in Hungary, where the original Zeiss Conquests were first produced. But in 2013, Zeiss launched their Terra line of binoculars which, with the exception of the small 25 mm pocket binoculars, were, at least at first call, assembled in China. I remember the outrage on some of the popular forums about this move by Zeiss to the Far East. What were Zeiss thinking? For some, this was going to be Terra Incognita from Zeiss, or was it? Well, it turns out that all of their top line binoculars are very expensive and so were in no direct competition with the lower end of the market, where many companies were beginning to offer good binoculars – like the Nikon Monarch 5 and 7 range – in the sub $500 price class. Zeiss clearly felt that they too could compete in this binocular price class but to do so would have to move production to China where labor costs were substantially lower than in Germany. In 2019, the Terra ED binoculars got a small face lift, with subtle improvements to the ergonomics of these binoculars and are still being offered in 8× and 10×32 as well as 8× and 10×42. I’ll be discussing the 42 mm models here. The Zeiss Terra ED 42 mm binoculars come in three colors; black, green or grey. They are both very modern-looking to the eye, with their fiberglass-reinforced polycarbonate chassis overlaid by a textured rubber armoring. They feel very nice in the hand with their single hinge design and central focuser. They’re nice and compact, being only 14 cm long, 12 cm in width, and weighing around 725 g, they are quite lightweight for their configuration. Like the Zeiss Terra ED pocket described at length in my Chap. 3 on pocket binoculars, they come with very nicely engineered twist-up eye cups that hold their positions firmly indeed. Eye relief is generous on the 8×42 model – 18 mm – but only offer 14 mm in their 10×42 model, making it a challenge for eyeglass wearers to engage with the entire field. The focus wheel is smooth and precise, taking about one and a half turns from one end of the focus range to the other. Most users describe it as intermediate in speed between very slow and very fast focusers, allowing it to be used for most outdoor activities from birdwatching to hunting. The diopter adjustment is made by turning a ring under the right eyepiece – just like many other instruments in this price class. It’s reported to move a little too easily for some people’s taste though, but I found my 8×42 sample just fine. Neither does it have a numerical scale so that you can quickly move the ring to your preferred setting. Zeiss engineered a lot of hi-tech features into these Terra binoculars; the objectives feature Schott ED glass made in Germany, and all optical surfaces are fully multi-coated to minimize stray light and internal reflections. The images are very bright (88% light transmission) and impressively sharp across most of the field of view, with a little bit of edge softness creeping in. The exterior lenses are treated with the company’s proprietary LotuTec coating, which repels water. Any condensation build-up on the binocular eyepieces simply diffuses in a matter of seconds! Chromatic aberration is well controlled – some say even better than their higher-end

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models such as the Conquest HD line of binoculars, but the field of view is distinctly average; just 7.13 degrees for the 8×42 model and 6.28 degrees for the 10×42 Terra ED. Glare suppression was also exceptionally well controlled on my test 8×42 unit and pincushion distortion is very low even near the field stops. Colors really pop thanks to their having Schott ED glass and contrast is well above average. The warranty is a little disappointing though – 2 years – compared with the 10-year warranty on their higher-­end models. The Terra EDs come with ocular and objective covers, a cute clamshell case, a lens cleaning cloth, instruction sheet and a good quality neoprene carrying strap with the pretty Zeiss logo. Are the Terra EDs for you? Well, that depends. I personally rate them very highly. If you’re a keen novice nature enthusiast, they provide very pleasant views, but more experienced observers are likely to get bored with them quickly as they don’t quite have the ultra-wide and uber clarity apparent on their more expensive offerings, but you get still get a very quality optical experience and that famous Zeiss name that cuts above many of the rest in this binocular price class. You can get substantially better bang for your buck if you do some careful research, but in my experience the Terra ED 42mm binoculars are very hard to beat in their $500 price class.

A High Class Binocular from the Czech Republic Now for a real touch of class. The highly respected Czech-American company, Meopta, has delighted customers with an excellent array of optical instruments since 1933 The company’s flagship line, the MeoStar B1 Plus, comes in a variety of formats from 32  mm right up to 56  mm models. They deliver very high-quality European optics at very competitive prices. Built on the legendary B1/B1.1 aluminum alloy chassis with a central locking diopter, the B1 Plus features enhanced optical tolerances to provide even sharper images and greater optical performance. In addition, the B1 plus feature MeoShield and MeoDrop exterior coatings that protect the lens surfaces from scratches and makes cleaning oils and other contaminants easy without leaving residue. It’s completely redesigned exterior rubber armor gives the user a more solid grip, contoured to better fit in the hand for comfortable use in the field. The diopter compensation is built into the focus wheel. Pull up the focuser, adjust as per your required setting and push it back in once you’re done. The company’s proprietary MeoBright coatings ensure an 88% light transmission (confirmed by allbinos measurements) delivering bright and crisp images in all conditions. The field of view of the 8×42 Meostar B1 Plus is 7.88 angular degrees (the 10× model has a 6.3 degree field in comparison) – not the widest by modern standards but the edge-to-edge sharpness makes it appear wider than it really is. Color tone is reported to be on the warm side, which I think looks nicer than a cooler more neutral cast seen in some other alpha class binoculars. But quality like this results in heftier weight. The 8×42 model tips the scales at 905 g, making it one of the heaviest instruments in this full-size binocular class. One wonders why such a state-ofthe art instrument as this is still being designed using aluminum when the considerably lighter magnesium alloy is now used even on mid-priced and

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budget-priced models. That said, I don’t hear many complaints from the lucky owners of these binoculars, especially when you factor in the price tag of about $1900, a saving of several hundred dollars more than the equivalents from Leica, Zeiss and Swarovski. The Meoptas are built like proverbial tanks and should endure a lifetime of regular use.

Meopta Meostar B1 Plus. (Image Credit: Meopta Sports Optics)

Upper Tier Binoculars from Vortex

The Vortex Viper HD 8×42. (Image Credit: Vortex Optics)

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A good step up in quality from the popular Diamondback HD series, the Vortex Viper binocular line was launched in 2006. In 2011 the first-generation Vipers got a makeover to the Viper HD line. Then in 2018 the binoculars got a completely new optical system but the number of models in the line decreased to just four so was limited to the instruments with the following parameters: 8×42, 10×42, 10×50 and12×50. What’s new? Well, the field of view was enlarged from 6.6 to 7.8 degrees, much more in line with most other an 8×42 instruments. The eye relief however was decreased from 20 to 17 mm and the minimum focusing distance went from about 1.7 to 2.0 meters. The new model also gained a bit of weight over earlier incarnations but is still one of the lighter offerings in this mid-tier market, tipping the scales at slightly under 700  g. The good news is that Vortex didn’t hike their prices up when the new vipers were launched. The Viper HDs feature many nice optical properties, such as extra low dispersion HD glass and HR fully multi-coated layers in the optical construction. The BaK4 Schmidt-Pechan prisms feature phase-correction and dielectric coatings for brighter, crisper and higher-contrast images. Exterior elements are protected by Vortex’s proprietary hydrophobic ArmorTek layers, which are supposed to guard them from scratches, oil, and dirt. Like other Vortex binoculars, the Viper HDs are argon purged to prevent internal fogging of the optical surfaces. These instruments also have a locking diopter located under the right ocular lens. Push the ring up to adjust and then push it down again. That said, some reviewers have reported that it’s a bit flimsy, sometimes even breaking without any notice. The well-made twist-up eye cups offer four different positions and hold them very well. Handling of the Vortex Viper HD 8×42 is excellent thanks to the thumb rests built into the belly of the binocular as well as the textured green rubber armoring. The field of view is a generous 7.8 degrees, though some reports place it nearer 8.0 degrees. Chromatic aberration is all but absent in the center but some lateral color creeps in as high-contrast targets are moved off axis. Glare suppression is also noticeably better in the Viper HDs than in the more economically priced Diamondback HDs. If you’re after a reliable binocular that delivers satisfying views in all weathers, they’re well worth a look and retail for about $640. Moving up a step or two in quality, the Vortex Razor UHDs from Vortex are the company’s flagship line of high-performance binoculars. Unlike the Viper HDs which are made in the Phillippines, the Razors are manufactured in Japan. The first thing you notice is its very pleasing ergonomic design, with a modern open bridge and oversized central focus wheel. The long barrels are slim tapered and covered with a grayish-green rubber armoring that afford excellent grip. Like the Viper HDs, the underside of the barrels have thumb-grabbing dimples on their undersides, allowing users to keep the binocular balanced in most any conditions you’re likely to encounter. That ergonomic touch renders the Razor UHDs feel lighter than they really are (918 g). That heft is worth noting, though, because it comes from a quality of glass that many entry-level and mid-price binoculars don’t use. Vortex employs a variety of

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Japanese extra-low-dispersion glass in the Razor UHDs and heavier Abbe Koenig prisms that collectively contribute to that heft. Good glass is heavy glass. The APO lens system features a number of color- and image-correcting lens elements. As you’d expect, these top-of-the-line binoculars, all the index-matched lenses are fully broadband multi coated using Vortex’s premium XR Plus coatings on the objective and ocular lenses. Those coatings help resist scratching too, as well as repelling dust and moisture, but other coatings on the UHDs reduce glare to an absolute minimum. Owners invariably report superb optical performance with the color balance veering towards the blue end of the visual spectrum.

Vortex Razor UHD 8×42. (Image Credit: Vortex Optics)

Interestingly, the Vortex UHDs don’t have a locking diopter but it’s very rigid and shouldn’t get moved out of its proper positioning easily. All the new Razor UHDs ship with the very useful and adjustable GlassPak binocular harness. It’s a $50 value, and a piece of gear that many hunters swear by. The accessories with the Vortex razor UHDs are excellent in every respect and backed the company’s lifetime VIP warranty for peace of mind. Are they worth their $2400 price tag? There are many loyal Vortex fans who’d say so!

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A Solid Performer from Leupold

The Leupold BX-4 Pro Guide HD 8×42. (Image Credit: Leupold Sports Optics)

The US sports optics company Leupold has been satisfying their customers for well over a century with high quality optics They manufacture an impressive range of roof and Porro prism binoculars. While their entry-level instruments are produced in China, their more expensive offerings are manufactured in Japan. Their Japanese-­made BX-4 Pro Guide HD series consists of six roof-prism pairs of binoculars with the following parameters: 8×32, 10×32, 8×42, 10×42, 10×50, and 12×50. Here, we’ll take a closer look at the 8×42 model. Almost uniquely at this price point, the optical system features fluorite elements that are supposed to ensure near-perfect correction of chromatic aberration. The BX-4 Pro Guide HDs have all optical elements fully broadband anti-reflection coated. In addition, the surfaces of outer elements are covered by hydrophobic coatings and the BaK4 Schmidt-Pechan prisms are phase and dielectrically coated. The chassis of the binoculars is nitrogen-purged and waterproof. Along with the instrument you get objective caps, a rain guard, a strap, a case, and a cleaning cloth for optics. The series comes with Leupold’s lifetime warranty. The binoculars have an excellent open bridge design that affords superior handling, even using one hand. The large centrally placed focus wheel moves with silky smoothness. The aluminum chassis is covered in textured rubber for excellent grip in all weathers. Tipping the scales at 680 g, you can carry these round your neck all day. One might expect a locking diopter on such a high-quality instrument but it’s located under the right ocular lens.

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So how do these $600 binoculars perform? Very well by most accounts. Chromatic aberration is very well corrected both in the center of the field and at the edges. Contrast, sharpness and glare suppression are also well above average, though with a 7 degree field of view, I’d say this could have been made a bit wider especially in this lower power, full-size class. Leupold’s Twilight Max Light Management System is advertised to maximize light transmission in low light conditions, but independent tests have showed an overall throughput of about 85%  – very good but hardly class leading. Many hunters, birders and outdoor enthusiasts return to Leupold again and again for their excellent product support. If anything happens your binocular, you can be assured that their repair team will fix it for you.

Engage Your Passion with a GPO Passion HD German Precision Optics not only produce and sell a very nicely performing Passion ED range of binoculars I showcased in the last chapter but they also offer extremely well designed Japanese-made ED binoculars embodied in the Passion HD line. Having sampled the Passion EDs, I was curious to see how their flagship HD models performed so ordered up the 10×42 for review. The package arrived double-boxed, with the instrument beautifully presented inside a very thoughtfully styled presentation box as shown above. The binocular was very snugly placed inside a high-quality foam frame, with a separate compartment for the custom- designed hard shell case. My immediate impression was “wow!” The care and attention to the presentation of this binocular was second to none: very reminiscent of what I had previously experienced with some high-end Zeiss instruments I encountered in the past! Opening up the choice quality case, I found all the accessories accompanying the binocular, including high-quality ocular and objective covers, a GPO-branded microfiber lens cleaning cloth, a very comprehensive instruction manual in several languages, a padded, logoed neck strap and carry strap for the case, and a warranty card. Everything about the package was a quality experience and it was clear to me that GPO had gone to great lengths to make this initial encounter with their product as special as possible. It certainly worked its charm on yours truly!

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The GPO Passion HD 10×42

The beautifully machined, twist up aluminum eyecups are a real work of art! Fit & finish wise: nothing like them on the market at this price level! Overlaid by soft rubber, they are very comfortable when pressed against my eyes. The long, slender barrels were very easy and intuitive to get my hands around, and on the underside my thumbs naturally settled into the two indents for a sturdy grip. Overall, I got the immediate impression that this instrument exuded quality: it had a fit and feel that is – in this size class at least – quite simply in a different league to anything I’ve had the pleasure of owning and using in the past. Without question, this is an alpha binocular build. The Passion HD 10×42 has a substantial (848 g) heft to it and feels very solid and robust in my medium sized hands. It has a small, single bridge connecting both barrels. It’s noteworthy that some of the leaders in the binocular industry have abandoned the open bridge design in favor of its single hinge counterpart. Just look at the design of Swarovski’s new NL Pure line to see what I mean. The twist-up eyecups are made from machined aluminum and are quite unlike any I had seen before. They are extremely tough and have one intermediate position between fully extended and fully retracted, with absolutely no wiggle room. Soft rubber envelopes the cups and are very comfortable to press your eyes against, even after hours of glassing. These oculars have plenty of eye relief too: I was easily able to image the entire field with my varifocals on with no issues. I would rate these eyecups as one of the very best I’ve seen and used: certainly, in a different league to anything made by Nikon and Zeiss, for example.

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The central focusing wheel is oversized compared with many other binoculars I’ve used but its exceptional quality is in evidence from the second you lay your fingers on it. Running through just 1.5 revolutions from one extreme of travel to the other, its movements are silky smooth and completely backlash free. Only minute adjustments are needed to bring an object into focus from several tens of yards distant to only a few yards distant, making it especially appealing to birders who often demand the best focusers on the market to sate their demanding schedules. I found the focus wheel on the Passion HD to be very similar to that found on the Nikon Monarch HG line, with similar levels of tension and smoothness. When considering the diopter adjustment however, the GPO Passion HD leaves many of its competitors in the starting blocks. To operate it, you simply pull out the focus wheel and adjust the image in the right barrel until it’s as crystal clear as that seen in the left ocular. Once completed, you pop it back in and voila, you’re off to the races! Compare this to the more cheaply designed locking right eye diopter on the Monarch HG or Vanguard ED II, for example, and you’ll quickly come to appreciate the sheer sophistication of the Passion HD line, which will never pop loose by accident or budge from its position once it’s set. That said however, some users have reported that the diopter shifts slightly out of the ideal position when its being locked back into the focus wheel but in my test unit, I never encountered any such behavior. Looking now at the objectives, they are deeply recessed to minimize stray light, and the encroach of rain and dust. I’m especially impressed by the truly excellent baffling of the objective lenses which really helps mitigate the most damaging effects of stray and intensely bright light sources, minimizing glare. But it takes more than good baffling do this well: the layers of coatings applied to each lens and prism surface also plays a crucial role here, as we shall see shortly. The eyecups are larger than on most other binoculars I’ve handled. They measure about 42 mm in diameter compared with 37 mm in many other models. This makes positioning your eyes that little bit easier in practice and affords greater comfort for eye glass wearers. Another important ergonomic feature is the hydrophobic coatings applied to the outer lenses of the instrument. GPO’s proprietary PASSIONdrop coating quickly disperses condensation that invariably occurs when glassing in cold or damp conditions. In a side-by-side test using a control binocular without these hydrophobic coatings, I was quite taken by the much shorter times needed to disperse a fogged-­ over ocular lens on the GPO.  Typically, such fogging can take a few minutes to dissipate without such coatings, in contrast to just a few seconds in the case of the Passion HD binocular. I carried such tests out at both room temperature and also outside, where the mercury hovered at or below zero for about an hour. Breathing on the ocular lenses only took a few seconds to clear. Playing the waiting game when this happens during field use can make all the difference between enjoying your subject or missing it entirely. The accessories accompanying the instrument are also of very high quality. The rain guard fits over the eyecups snugly. The objective cover is very reminiscent of those employed by Zeiss on their flagship Victory SF range. Instead of rubber rings that fit over the barrels, the GPO Passion HDs come with a single cap connecting both objectives by a rubber bridge. You push them into the objectives, where they

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tightly seal off the encroach of dust, water and other debris. GPO even included a spare one just in case the other gets lost. Neat! A hefty binocular like the GPO Passion HD requires a high-quality padded neoprene neck strap to get the best use out of it, and that’s exactly what one receives in the package. Such a quality strap helps to lighten the load especially when walking with the instrument over long journeys. Finally, a few words of praise for the accompanying carry case. In a word: Awesome! But to elaborate, it’s an attractive, green canvass hard shell case, which can be zip-closed. The carrying strap for the case is also padded. You have plenty of room to store the binocular with its strap inside and it even has an additional pouch to carry a cleaning cloth (also supplied by GPO) or sachet of desiccant. I rate it right up there with some of the best cases I’ve had the pleasure of using. My first test involved seeing how well the binocular handled a very bright light source. Such tests showed the GPO Passion HD produced a flawless result: there were no annoying internal reflections, no diffraction spikes and little in the way of diffused light around the intensely bright beam. That’s an excellent result, right up there with my control binocular, which also displays impeccable results in similar tests. My next test was to check collimation. It was spot on! Next, examining the eye pupils when a bright light source was passed through them displayed excellent results! The pupils were perfectly round with no evidence of truncation, and no significant light leaks around them. My notes show that these very clean pupils were considerably better than the Nikon Monarch HG I tested in a similar battery of tests. From the moment I took my first look through the GPO Passion HD I was stunned by its amazing sharpness, contrast and lack of glare. Arriving in the late afternoon with the light fading fast, it was a race against time to attach the neck strap and venture out. But even in these highly unfavorable conditions, the Passion HD threw up stunning views of the surrounding landscape. The sweet spot appeared enormous; indeed it remained impressively sharp right up to the field stops. Field curvature and pincushion distortion are unusually mild, with only slight warping of a vertical telephone pole observed at the field edge. Truly impressive! Colors really popped in this high-performance glass, especially greens, reds and browns. Micro-contrast details were abundantly in evidence when I imaged some remaining autumn leaves against a bright blue sky. The level of detail I recorded was simply breath taking! I could make out the intricate veins in the leaves and the variegated hues of the secondary pigments now on full display. Taking it off to a favorite birding haunt, the Passion HD effortlessly picked off tiny birds hopping about in bushes some 70 yards distant. The ultra-precise focusing afforded by this binocular made it child’s play to distinguish Blue Tits, Tree Creepers and Goldfinches from this range. Lesser instruments struggle in similar tests, as my experiences had found. The GPO HD 10×42 is a glare suppression beast. Indeed, even after trying several difficult back-lit targets, I really struggled to make out any at all! Veiling glare is almost eliminated in this instrument. Looking up at the topmost boughs of a conifer tree with a bright overcast sky in the

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background usually shows an arc of washed-out milky light that robs the image of contrast, showing up at the bottom of the field of view. Try as I did to bring it out, I simply couldn’t to any significant degree. I’ve had it as close as 5 degrees away from the Sun and the details still pop! These results were way above what I had come to expect from a binocular in this price class. Indeed, glare can be a significant issue even with the very best binoculars on the market. Even under dull, overcast conditions the images served up by the GPO Passion HD are bright and full of contrast. This binocular has very high light transmission. I attribute this to the application of state-of-the art multilayer coatings to the prisms and lenses but also to the rather unusual nature of the objective design, which utilizes two ED elements as part of a cemented triplet configuration. This is an old school solution to boost light transmission by minimizing the number of reflective surfaces the light must pass through. GPO claim an overall light transmission of 92% for this optic and when you look through them it’s not easy to dismiss! The boosted light transmission becomes readily apparent in low light conditions, such as on cold, dull winter days, and at dusk and dawn. My tests show the GPO Passion HD really accentuates greens and browns as the light fades. The images remain tack sharp and full of intricate detail well after sunset. In another test, I compared a very good 8×42 ED with the 10×42 Passion HD. Though the light transmission of the former is less than the latter, it does have the perceived advantage of having a larger exit pupil (5.25 as opposed to 4.2 mm). Comparing both binoculars as the light rapidly faded after sunset in late November, showed that the 10×42 produced equally bright images for most of the time, but I could still make out finer details than with the 8×42 ED even as the last vestiges of light disappeared from the landscape. These tests convinced me that this would be a fine binocular to use at dawn or dusk, for hunting or general surveillance. The thorny issue of chromatic aberration always comes up in any detailed binocular discussion. My tests show that there is vanishingly low secondary spectrum in the center of the field but can be coaxed out of very high contrast targets as the object is moved off axis. I did not find this lateral color to be distracting. And for the record, all binoculars will show some if you search for it. In yet another test, I aimed the binocular at a bright, waxing gibbous Moon. The view was razor sharp and devoid of any false colors on axis. Moving the Moon to the edge of the field does show a little lateral color; all par for the course in any top-tier binocular with these specifications. My reading of the literature uncovered some discrepancies in the size of the field of view offered up by the Passion HD. Some claimed it was as small as 6.0 degrees while the specifications on the GPO website listed it at 6.4 degrees. Faced with these discrepancies, I decided to perform the most accurate test I could think of to resolve this. Venturing out after midnight, I chose the star Mintaka, which has a declination very close to the celestial equator and well positioned at the time very close to the meridian. I centered it in the field of the binocular and timed how long it would take for it to drift across the field from the center to the field stop. The result I got was 12 min 26.45 s. Doubling this value for the entire field gives 24 min 52.9 s. Plugging these numbers into the astronomical formula yielded a true field of

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6.237 angular degrees. I suppose I should have done this a few more times and taken the arithmetic mean, but the uncertainties are small, and I do have better things to do in my life! The stars are also a great way to measure how much distortion there is at the edge of the field. Conducting such tests produced brilliant results. Stars remained beautiful pinpoints across the vast majority of the field, only showing slight distortion at the field stop. That’s an excellent result, agreeing well with my daylight tests and affirming my conviction that the Passion HD is an outstanding binocular for stargazing. In another test, I moved the Pleiades asterism and the Moon from the center to the edge of the field, looking to see if there was a drop off in illumination. I was delighted to see that there was very little loss of brightness on either target, indicating that the binocular field is quite flat and evenly illuminated. You’re going to have an absolute ball using this instrument under the starry heaven! In summary the optical performance of the Passion HD is truly world class, right up there with the best instruments manufactured by Zeiss, Leica and Swarovski, but without the hefty price tag. The GPO Passion HD 10×42 has good close focus. I measured it at only 1.9 m, so slightly less than the advertised 2 meters. This greatly increases its versatility in field use, as it enables the user to view close by objects in exquisite detail. You wouldn’t normally associate a 10×42 with a great butterfly binocular but that’s exactly what it can do if necessary. The GPO Passion HD is very easy to use with thick gloves during cold winter days. Smaller instruments, in contrast, are much more challenging to negotiate with gloves on. It’s just one of the many advantages of using a larger sized binocular. I’m especially glad that GPO did not resort to any “electrickery” here, in going for an overly complex eyepiece design for the Passion HD series, as it’s entirely without issues like blackouts and the rolling ball effect you often get while panning binoculars with built-in field flatteners and long eye relief. This instrument really comes into its own when scanning landscapes, as the views are so comfortable and immersive. It’s almost as if you are really sitting in the image. I’ve enjoyed some stunning views with this instrument on dull winter afternoons, when I used it to identify a new bird at one of my local patches: a colorful but somewhat noisy Jay, hiding out among the trees. Though I could not get closer than about 80 yards, I was still able to resolve its beautiful plumage: beige, black, blue and white. The extra reach of the 10× glass really came into its own, as an 8× would have come up a bit short on this occasion. For me, it’s magical moments like this that really help you bond with a binocular. There is little about the GPO Passion HD 10×42 that I could fault. Indeed, I cannot recommend this instrument highly enough. Ergonomically and optically it just ticks all the boxes and will delight anyone who uses it. Its robustness will undoubtedly guarantee many hassle-free years in the field, and the excellent European 10-year warranty will also put your mind at ease in the unlikely event that you hit a snag with it. The GPO Passion HDs retail for about $1000.

Two High-Performance Roofs from Oberwerk

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Two High-Performance Roofs from Oberwerk

The Oberwerk Sports ED 8×42. (Image Credit: Oberwerk)

US-based Oberwerk, a company that has established itself as a leading supplier of high-quality astronomical binoculars, has recently waded into the sports optics market with the launch of their appropriately named Sports ED binoculars. Coming in 8×42 and 10×42 formats, these feature a light-weight magnesium alloy chassis chock full of high-end features including a fully broadband multicoated optics, dielectric and phase corrected BaK4 roof prisms and an FK-61 ED objective lens element to cut chromatic aberration to an absolute minimum. I put the 8×42 model through its paces and was duly impressed with its optical and ergonomic performance. For one thing, it’s an exceptionally handsome binocular with a dark green rubber armouring contrasting well with a bright red anodized focus wheel and diopter ring. It’s fairly light weight for an 8×42, tipping the scales at just 720 g. The armouring is nicely textured for gripping in the hands. The ridged metal focus wheel moves with silky smoothness, one of the best I’ve personally experienced, with no free play that I could detect. The right eye diopter has a fair amount of tension which makes it difficult for it to move out of place accidently. Optically, the Sports ED delivers in spades; bright, sharp, with vivid colors and excellent contrast. I did detect some glare though during extensive field use but this

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can be removed by shading the objectives with your hand. Apart from this, it behaves more like a $1000 optic. The sweet spot is very generous, with some mild softness creeping in near the field stop. The 8×42 model has a very generous field of view; 8.1 angular degrees, whereas the higher power 10×42 model delivers a very respectable 6.5 degrees. The 8×42 model I tested had a close focus just over 2 m, making it an excellent choice for those who like to watch insects, rocks and plants up close and personal. Both the Oberwerk Sports ED models are available at the same price of $329.95.

The Maven B1.2 8×42

Maven B1.2 8×42. (Image Credit: Maven Sports Optics)

Established in 2013, US-based Maven is a relatively new name in the outdoor optics industry. The founders built it out of a shared vision. To deliver high-quality and high-performing binoculars directly to consumers. Maven has developed several product lines of binoculars. Similar to Nikon or Steiner, they provide a price and quality scale from which consumers can choose. One of these product lines is the award-winning B series. The Maven B1, which comes in both 8×42 and 10×42, was the flagship model under this series until the company launched the Maven B1.2 – 8×42, in early 2021. The Maven B1.2 – 8×42 is the company’s general-purpose, do-it-all binocular. Designed by sportsmen for sportsmen, it’s packed full of high-quality Japanese optical features that make it a joy to look through, including fully multi coated

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lenses, phase corrected prisms with dielectric coatings, high-index Bak4 prisms and ED glass. These features collectively ensure a great optical experience with sharp, high-­contrast images in vibrant natural color. As an updated version of the Maven B1 – 8×42, these binoculars are an improvement on the original B1s. In addition, you’ll find the new B1.2s to be significantly more compact, portable and lightweight (760 g) than its predecessor thanks to the magnesium alloy chassis without losing robustness. They are also very eyeglass friendly thanks to their generous 18.1 mm of eye relief. The all-new Maven B1.2 – 8×42 serves up a field of view of just over 8 angular degrees -ideal for many glassing activities and an improvement over the original B1 model which sported a field of view of 7.4 degrees. On paper this doesn’t sound like a lot but it amounts to a 17% hike in the field of view by area. These binoculars come with the same extra-low dispersion (ED) glass as its predecessor producing images that are tack sharp, exceptionally clear, bright and high- contrast images both at range and in low light. In addition, the external lenses have an effective oiland scratch-resistant coating increasing the instrument’s durability. As you’d expect from a high-performance instrument like this, it’s nitrogen purged and fully waterproof, tested at a depth of 1 m for half an hour (so IPX-7). This a top tier binocular by almost anyone’s estimation and it’s available at a good price – $807 – but you’ll have to order from Maven directly. The company also offers their customers a B1.2 10×42 for greater reach. It’s got an impressively wide field of view for a 10× glass – a good 6.6 degrees – making it one of the most expansive fields in the sub $1000 dollar binocular price class. Like its lower power sibling, it offers impressive sharpness nearly all the across the field. Color correction is also reported to be very good with only a trace glimpsed on the highest contrast objects. Contrast is also top notch and it’s also got a very impressive close focus of about 1.5 meters. And with 17.8 mm of eye relief, you’ll be able to enjoy the entire field using eyeglasses. The Maven B1.2s come with a nice wide neoprene strap, ocular and objective covers. I would take issue with the carry case though, or rather cloth pouch the B1.2s come with. Personally, I wouldn’t feel comfortable holding such a nice binocular in such a pouch. I would like to see a hard case offered with these instruments.

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A Top Performer Form Opticron

The Opticron Aurora BGA VHD 8×42 has a beautifully designed and rather understated chassis

In March 2021, the UK-founded company, Opticron, released their newest flagship model, the Aurora BGA VHD in 8×42 and 10×42 formats. Designed to improve on their previous high-end model the DBA HD, the Aurora sports a new apochromatic optical system with the highest-grade ED glass, field flatteners and a very impressive 8.1-degree field of view. Intrigued, I ordered up a unit for testing. The instrument arrived in a very attractively designed black cardboard box, with a magnetic fastener. The instrument itself was found inside a beautifully designed corduroy case made in Germany. I later learned that Swarovski package some of their world class optical wares inside cases made in the same factory. I really like the feel of corduroy, especially in hot, clammy weather. The instrument itself was packed with both its rain guard and tethered objective covers attached. The package also contained a very high-quality padded neoprene neck strap, a logoed microfiber cloth, instruction manual and 30-year warranty card. Holding the instrument in my hands, I was immediately taken by its very elegant, yet somewhat understated form factor. The magnesium alloy chassis is overlaid by a tough matt black rubber substrate which is very easy to grip. Unlike the DBA HD+, Opticron decided to ditch the open bridge design in favor of a tough, single bridge connecting the two barrels. Examining the underside of the binocular showed no thumb indents, which came as a relief to me. I rarely find good use for them, as I enjoy the freedom to

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find my own positions without prompting. The twist up eye cups have four positions to suit most anyone’s preferred eye relief. They lock into place and hold their position fairly well but I would like them to have been a wee bit firmer though as I found they wobble a little after being set in place. The focus wheel is a little over a finger’s width and moves smoothly and precisely. The diopter setting is achieved by pulling up the top plate on the focuser and turning it to your ideal setting. The ocular field lenses are large and easy to engage. I measured their diameter to be 24 mm. Tipping the scales at just over 700 g, the Opticron Aurora BGA VHD 8×42 is on the light side for such a high-performance instrument. The instrument feels very solid in my medium sized hands. There is plenty of room to grip it either with one hand or two. The instrument has excellent eye relief – something that Opticron seem to be especially adept at achieving. It’s a full 20 mm. Keeping the eyecups down, I was able to engage with the entire field with comfort with my varifocals on. The hinges on the central bridge are on the rigid side. But that’s a good thing. Once you’ve adjusted the binocular to accommodate one’s optimized IPD, it doesn’t budge without a reasonable degree of effort. The diopter adjustment is idiot proof: pop up the plastic plate on the focuser and rotate it to one’s desired setting and then pop the plate back down again. While it has no scale, it does not jolt out of position once the plate is pushed back in again. This is a better solution than other lockable diopter designs I’ve previously encountered, such as those seen on the Monarch HG or Vanguard Endeavor ED II, for example. The centrally positioned, milled focus wheel moves through about 1.75 anti-­ clockwise rotations from closest focus to infinity and a little beyond. The gearing is backlash free and near ideal, especially for birders, who often benefit from smooth, accurate but rapid re-focusing. I’ve learned to never underestimate the value of a comfortable strap when using larger, heavier binoculars. The padded neoprene neck strap supplied with this instrument is excellent; very easy to attach, and very comfortable to wear even after many hours of glassing in the field. All in all, the Opticron Aurora BGA VHD is a beautifully designed instrument that should meet the approval of most individuals who use it. My optical testing began as usual, by examining how the binocular handled a very bright light source. The results I obtained were excellent. There were no internal reflections, no diffraction spikes and no signs of diffused light around the light source. These results reveal the very high homogeneity of the glass and the excellence of the anti-reflection coatings applied. Turning the binocular on a bright sodium streetlamp after dark, I got a very fine image. What was even more impressive was the off-axis suppression of stray light. Bringing the sodium streetlamp just outside the field showed no ghosting of any description. I also tested this on a bright gibbous Moon in deep twilight. Putting the bright silvery orb just outside the field showed no sign of flaring or ghost images. Next I examined the exit pupils which were perfectly round with very little in the way of light leaks in their vicinity. So far so very good!

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As I put the binocular to my eyes I was amazed by the wonderful quality of the image. Indeed, it was, to all intents and purposes, sensibly perfect. The field of view is impressively large at over 8 angular degrees. Scanning the pretty flower beds on a bright sunny day in my next-door neighbor’s garden, the Aurora snapped to an ultra-sharp focus, presenting their variegated hues in beautiful natural color, owing to the complete lack of glare in the image. Contrast was superlative also, as was the edge-to-edge sharpness. Taking the instrument out on a dull, overcast day stubbornly refused to show up any glare. Usually, looking at the ridge of a hill against a bright, cloudy sky will often produce some veiling glare, but this top-tier instrument from Opticron refused to show anything of significance. Chromatic aberration tests also proved exceptional in this binocular. Carefully examining a telephone pole against a dull overcast sky near sunset showed up none in the center of the image. What was extraordinary though, is that the same instrument refused to show any lateral color until the pole was placed right up near the field stop where the merest trace of it was unveiled. The same was true when I examined several layers of leaves on a tree against a bright overcast sky. Only at the edge of the field could I detect a trace. These results were exceptional. But to elaborate, the control of secondary spectrum in the Opticron Aurora BGA VHD was much better than both the Leica Trinovid HD and the GPO Passion HD, as my notes revealed. Scanning the edge of a forest in bright summer sunshine showed no significant blackouts and very little in the way of a rolling ball effect. This was another genuinely surprising result, as I was expecting both these artefacts to be more pronounced. Barrel distortion was very mild in the Aurora too, as evidenced by examining a stretch of fencing about 50 yards distant, moving it first to the top and then to the bottom of the field. Collimation was shown to be just about perfect, as judged by using the diopter adjustment to deliberately defocus the image of the bright star, Vega. I used the gibbous Moon to test for off axis blurring, chromatic aberration and to assess illumination drop off as it was moved off axis. The results were very impressive here also. The Moon remained razor sharp, with excellent contrast nearly all the way to the field stops. No unwanted color fringing was in evidence until the orb was swung right out to the edge of the field, when a faint yellow fringe was detected. There was a modest drop off in illumination though, but no more than I’ve seen in other top-­rated binoculars. Stars remained stubbornly sharp pinpoints of light across most of the field, only showing slight distortion at the field stop. This will make a first-rate astronomy binocular, as my extended night tests were to reveal. Close focus in the Aurora BGA VHD was measured to be 1.94 m, in close agreement with the advertised stats and considerably better than their previous flagship model, the DBA HD+, with its 2.5 m close focus. Most of my targets from about 30 yards right out to over 500 yards were sharply focused simply by rotating the focus wheel a mere quarter of a revolution or so. The instrument is supremely easy on the eye  – I call it the Big Easy  – very comfortable, immersive and highly engaging.

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Indeed, I gave it to a number of my family members to test out and everyone agreed that it was a joy to hold and look through. It was a real pleasure testing out Opticron’s flagship roof prism model, the Aurora BGA VHD 8×42, which proved itself to be an excellent performer, both optically and ergonomically. I feel it is arguably one of the best buys a prospective buyer can secure for well under £1000 in today’s market. This, together with the company’s excellent 30-year warranty, makes it a viable alternative to other highend models like the Nikon Monarch HG, the Leica Trinovid HD and the GPO Passion HD, and is sure to reward the user with excellent performance in any viewing conditions thanks to its excellent hydrophobic coatings applied to the outer lenses.

Top Quality Glass from Swarovski

The Swarovski EL 8.5×42

Arguably one of the most successful binocular models in today’s market is the EL series of binoculars from the famous Austrian firm Swarovski. In particular the 8.5×42 EL enjoys great popularity among birders hunters and serious nature enthusiasts. I had a chance to spend a few days with a first generation EL 8.5×42 and was suitably impressed by the experience. The first thing that jumped out at me is how sturdy the instrument is, even after 12 years of use by a keen hunter This is one

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solidly made instrument with its curvaceous barrels, and innovative open bridge design and a tough green rubber armoring. The focusing system on the unit I tested has been upgraded as well – this optic focuses down to 2.07 meters and the viewer can go from infinity to minimum focus with 1.5 clockwise rotations of the center-focus wheel. A wide-angle field of view and truly noteworthy eye relief contribute to this fine sporting optic’s viewing performance. Even when wearing glasses, the view remains unobstructed, free from vignetting and lush with crisp details. Eye relief is a very comfortable 19 mm, which means you can easily access the entire field using eyeglasses. It’s a bit on the heavy side though at 820 g, but I suppose a high-quality glass like this ought to feel hefty given the sheer amount of expensive glass going into its design. The EL 8.5×42 has many of the state-of-the-art optical coatings seen on later models including Swarodur, Swarotop, SwaroBright and Swaroclean, making it ideally suited to harsh environmental conditions where top optical performance is a necessity. By directing a bright beam of light inside the binocular I was pleased to see good results after all those years of field use. Only a few minor internal reflections were recorded around the beam but it was certainly more than I could see in a good quality mid-priced modern binocular. I also picked up some minor reflections on a bright sodium streetlamp and when examining a bright full Moon against a dark clear sky. The images by day were very impressive however, with excellent sharpness from edge to edge thanks to the built-in field flattening lenses that form part of the eyepiece optics. Contrast was generally excellent and colors bright and vivid. I did however pick up some veiling glare in some harsh outdoor lighting and when glassing near a bright setting Sun, more glare was easy to tease out of the binocular. Swarovski are well known to have some glare issues, as reported by many experienced observers. The newer ELs are well worth checking out if Swarovski is your thing. That’s especially true now since their retail price has been lowered in the aftermath of the introduction of the company’s flagship line, the NL Pure. The newer EL 8.5×42 has a slightly wider field of view of 7.6 degrees. It also has a number of ergonomic upgrades from the original model. For example, the traditional strap lugs have been replaced by a state-of -the-art quick-release mechanism. However, the weight of the newer EL 8.5×42 has increased a little to 835 g. Anything to dislike? Not much, but a better close focus than 3.3 m would be desirable to a lot of users. Which brings me to Swarovski’s top-of-the-line binoculars, the NL Pure series. The Swarovski NL Pure binoculars were introduced in 2020. They are the latest addition to Swarovski’s binocular lineup and are designed to provide a new level of optical performance and user comfort. The first NL Pure models came in the 42 mm format with three different magnifications; 8×, 10× and 12×.Since then, Swarovski introduced two smaller models: the 8× and 10×32. The NL Pure binoculars have quickly gained a reputation as one of the best binoculars available in the market for birdwatching, wildlife observation, and other outdoor activities that require high-­ quality optics. The Swarovski NL Pure 8×42 binoculars are a premium set of binoculars designed for bird watching, wildlife observation, and other outdoor activities where

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clear and detailed views are required. The NL Pure series, is known for its worldclass optics and innovative design. Of all the NL Pure line, the 8×42 is widely touted as the best birding binocular in the world. The NL Pure 8×42 binocular has everything the EL 8.5×42 has and more besides. Let’s start with the body. Gone is the open bridge design found on the EL series and a return to using a narrow single bridge with unusually long barrels. Gone too is the locking diopter mechanism located by pulling up the focus wheel. Instead, there is a rotary lever just behind the focus wheel which can be manually adjusted. Moving the lever takes some effort but once it’s adjusted it stays in place rigidly. The scale is located under the bridge, in case you’re wondering. Swarovski must have listened to their customers when designing this diopter compensation device, as it makes it much easier to adjust while looking through the instrument. The binoculars are designed with a large focusing wheel that is easy to use even with gloves on. Close focus is reported to be under 2 meters. The NL Pure has a very ergonomic design with a non-slip rubber coating, making them comfortable to hold for extended periods of time. It’s got some heft to it though, weighing it at about 870 g without the neck strap. The NL Pure 8×42 binoculars use Swarovski’s Field Flattener technology, which ensures a sharp and clear image from edge to edge. The field of view is positively enormous- a whopping 9.1 degrees! And, as you’d expect, the NL Pure is jam packed full of Swarovski’s SWAROVISION technology, which provides a high-­ contrast, color-neutral image. The binocular is also waterproof to 4 m depth and fog proof, making them suitable for use in all weather conditions. The view really delivers a huge Wow factor; tack sharp, crystal clear, beautiful contrast and lively colors. And even though it serves up an enormous field, it’s sharp right to the edge creating the feeling that’s its even wider than it really is. Chromatic aberration is essentially absent from the image, even near the field stops. Some critical reviewers have noted that it still suffers somewhat from glare when pointed toward strongly backlit scenes. The extremely flat field delivered by the NL Pure makes it ideal for astronomy too, pulling in sumptuous details of myriad deep sky objects and the silvery Moon. As you’d expect, Swarovski provide quite a lot of accessories to get the most enjoyment out of this state-of-the-art binocular. One such example is the forehead rest. Swarovski first introduced this concept with the BTX scope binocular eyepiece, but this is the first time they’ve put it on a binocular. It is a little soft rubber piece on a curved plastic frame, that sits on top of the bridge. A little knob adjusts the extent to which the brace protrudes upward from the bridge. The idea is that you set it to rest firmly against your forehead, when it provides a third stabilizing point for the binocular, beyond just your hands. Though it sounds a bit gimmicky, many users find it to be remarkably effective. Overall, the Swarovski NL Pure 8×42 binoculars are a premium set of binoculars that offer superb image quality, ergonomic design, and rugged construction. They are ideal for bird watching, wildlife observation, and other outdoor activities where clear and detailed views are required. This state-of-the-art instrument doesn’t come cheap. Expect to pay $3300.

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Optical and Ergonomic Perfection: The Leica Noctivid 8×42

The Leica Noctivid 8×42 in Olive Green. (Image Credit: Sam Shepherd)

Leica’s flagship birding binocular, the Noctivid, is named in honor of the Little Owl, Athene noctua, which Leica describes as “a symbol of wisdom and perfectly adapted to its environment”. They might have a point there! Curiously, only two models are offered: an 8×42 and a 10×42. Built like a proverbial tank, the Noctivid’s exude ergonomic and optical excellence with some of the highest standards in the industry. Like the Swarovski ELs, the Noctivid’s have an open-bridge design that is simple and elegant. The magnesium alloy chassis is covered in a thick rubber substrate which is non oxidizing. Two color schemes are available; either an olive green featured above or black, with the beautiful red Leica logo adorning the end of the right barrel. It’s textured beautifully and has excellent grip. There are no indents or ridges on the underside of the binocular to suggest where to put your thumbs but I find this never matters much in field use. The focus wheel is a little smaller than that found on other premium roofs such as the Swarovski Els or the Zeiss Victory SFs but plenty big enough to engage with easily. 1.5 revolutions bring you from closest focus to a little bit beyond infinity. Like other high class roof prism binoculars from the European manufacturers, the diopter compensation is built into the focus wheel, which is accessed simply by pulling it up and down. The Noctivid offers up arguably one of the finest binocular view available; the 8×42, in particular, provides a relaxed, immersive view full of high contrast details and beautiful color rendition. Owners describe the glass as almost jewel-like. But

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some critical observers have noted its higher levels of chromatic aberration off axis compared to other premium models. And while the Noctivid employs field flatteners, it’s not as flat as those premium models from Swarovski and Zeiss. As a result, edge of field performance suffers a little. In addition, the field of view – 7.7 degrees – isn’t the widest by any measure – but its wide enough to entertain most anyone for hours on end. And while it’s very compact, it is rather on the heavy side – 860 g – so something to consider if you aim to travel light. The Noctivids retail for about $2850. These are just a small, but I think, representative sample of the kinds of full-size binoculars available on the market. It’s my fondest hope that the reader can use these reviews to make informed decisions about buying a high-quality optic for your intended purposes. In the next chapter, we’ll be taking a look at a rather more specialized corner of the sports optics market, where we survey the world of low light binoculars.

Chapter 6

Low Light Binoculars

The binoculars discussed so far have apertures below about 42 mm, and sporting exit pupils of about 5 mm or less. Sometimes though, it pays to have a binocular that is good at picking off details in low light conditions such as at dawn, dusk, in Moonlight, or when scanning inside a thick canopied forest where little light penetrates, especially on dull, overcast days. In such situations it’s a very good idea to investigate binoculars having larger apertures and or lower magnifications to increase the size of the exit pupil in order for your eyes to gather as much light as possible. As you might imagine, low light binoculars are very popular among hunters, who often do their best work just before or after sunset or just before the sun rises in the morning. This chapter will explore this special class of binocular – used for low light applications. Before surveying this end of the binocular market, I’d like to dispense with a widely believed myth promulgated by some binocular enthusiasts on internet forums. Some claim that it’s possible to get a brighter image through binoculars than seen with the naked eye. This simply can’t be true. To see why consider the following. The exit pupil is the diameter of the circle of light that exits the eyepiece of the binoculars and enters the eye. The exit pupil diameter is determined by dividing the diameter of the objective lens by the magnification of the binoculars. For example, a pair of binoculars with 10× magnification and 50 mm objective lenses would have an exit pupil diameter of 5 mm (50 mm/10× = 5 mm). The human eye can typically dilate to a maximum pupil size of around 7 mm in low light conditions, although this can vary depending on age and other factors. This means that if the exit pupil diameter of the binoculars is smaller than the maximum pupil size of the eye, some of the light entering the binoculars will be blocked by the iris, and the image seen through the binocular will appear dimmer than what is seen with the naked eye. For example, if a pair of binoculars has an exit pupil diameter of 3 mm and the user’s pupils can dilate to a maximum of 7 mm, then only a fraction of the light entering the binoculars will actually enter the user’s eye, resulting in a dimmer © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_6

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image than what is seen with the naked eye. In this case, the maximum brightness of the binocular image would be limited by the size of the exit pupil. So when someone claims to see brighter images through binoculars than the naked eye brightness, it’s because they are seeing a well resolved object at higher magnification which may present the appearance of it remaining brighter but in reality it can’t be. Another parameter widely used in binocular circles pertains to the so-called Twilight Factor, which is supposed to indicate the relative effectiveness of a binocular to perform in low light. To calculate the twilight factor, multiply the binocular’s magnification by its aperture in millimeters and then take the square root of the resulting product. The higher this value, the better the binoculars are supposed to perform in low light situations and for astronomical use. Let’s consider two binoculars; a 7×50 and a 10×50, which will have twilight factors of 18.7 and 22.4, respectively. This would seem to indicate that the 10×50 will be better for low light observing at dawn or dusk say, but my own experience shows that a 7×50 provides the brighter images. Now let’s consider a more ridiculous scenario, comparing the twilight factors of a 12×20 to an 8×30. Both instruments would yield the same twilight factor, namely 15.5. However, the 12×20 would be next to useless in low light conditions, while the 8×30 would fair far better, all other things being equal. The real issue here is that it’s the size of the exit pupil that will greatly influence the outcome. The 12×20 has a tiny exit pupil of 1.67 mm while the 8×30 will be much larger at 3.75 mm resulting in a huge performance difference in low light glassing excursions. The real issue I have with the twilight factor is that it only considers two variables when in reality many other factors are not considered, such as the exit pupil, the quality of the lens coatings, the transmission rate of the glass, and the design of the prism system, can also affect the binoculars’ low light performance. And when stargazing the local conditions of the night sky play an enormous role in determining how a given binocular will perform. That said, many of the top sports optics companies quote twilight factors for their products as if they have a real bearing on low light performance. My advice is to dismiss these claims. Now back to the subject matter of this chapter. There are two main low light binocular configurations; 7×50 and 8×56. Both deliver a 7 mm exit pupil, which is the maximum size of the dilated pupil in fully dark-adapted conditions. Of course, delivering a detailed image in low light also requires good overall light transmission too. For this reason, many users still opt for high quality Porro prism models because they deliver good, bright images at reasonable cost, but roof prisms have been catching up fast over the last few decades. What are also commonly found on slightly older, low light binoculars are individually focusing eyepieces. That’s because many low light observations are made on the same target at more or less the same distance from the observer, so one usually begins by focusing both eyepieces for your eye before the light fades so that there is no need to re-focus when those low light conditions prevail. Newer models have conventional designs with an adjustable right eye diopter. Yet another common feature on low light binoculars are special rubber eyecups shaped like bat wings to block off unwanted peripheral light while observations are being made.

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It pays to remember that these will not reveal all their magic during bright daylight since your pupils shrink and will thus not deliver all the light it gathers to your eyes, but once the light fades, or if you glass in a dense forest with a with a heavy canopy an 8×56 will allow you to see many fine details in the shadows that are quite invisible to binoculars with smaller exit pupils. The 7×50 configuration has been around a long time. Indeed, this author’s very first binocular was in this configuration, which he enthusiastically used for casual daylight use and astronomy. Let’s begin with a survey of some popular models in this configuration.

A Great Low Cost 7×50 from Nikon

The Nikon Aculon A211 7×50. (Image Credit: Nikon Sports Optics)

Want a decent low light binocular but have a limited budget? I’d definitely give the Nikon Aculon A211 7×50 a test drive if I were you. For a little over $100, you get large 50 mm objectives, high-index BaK4 Porro prisms and multi-coated optics for bright, high contrast images. Users report excellent sharpness across most of the field, with just a little bit of peripheral softness. This sharpness is also aided by the use of aspherical lens elements in the eyepieces to help correct for field curvature as the image is moved off axis. The large, centrally located, textured focus knob, allows the user to quickly find the best focus, and the eyecups are fully modernized being able to be twisted up or down to achieve your perfect eye relief. While the other members of the Nikon Aculon series suffer from rather short eye relief, the 7×50 model has a generous 17.6 mm, making it eminently suitable for eye glass wearers.

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The tough, black rubber armoring is easy to grip and the 7× magnification guarantees nice, stable images. The field of view is a little small – 6.4 angular degrees – but one never gets the sense of tunnel vision while looking through the instrument. But the decent light transmission of the order of 80% and the large 50 mm objectives bring home a very decent amount of light in challenging conditions. The Nikon Aculon A211 7×50 is not exactly light weight though, tipping the scales at a little over 900 g, but many users get around this by attaching the instrument to a stabilizing tripod simply by unscrewing the cap on the end of the bridge and mating it using an appropriate adapter. The instrument is also waterproof though it is not filled with inert gas to prevent fogging up in cold, damp conditions.

A Waterproof 10×50 Porro Prism Binocular from Opticron

The Opticron Adventurer T WP 10×50. (Image Credit: Opticron)

With the rise of popularity of roof prism models, classic Porro prism designs have been unfairly demurred as the less desirable of the two designs. But nothing could be further from the truth, especially for low light and astronomical viewing. One excellent example of this Opticron’s Adventurer T WP 10×50. Here we have a lightweight (757  g), fully multi-coated binocular with high-quality Bak4 Porro prisms in a waterproof housing. Optically, it punches well above its weight, delivering excellent images of stars, nebulae and galaxies across its decent 6-degree true field. I had the opportunity of test driving this model in the summer of 2022. When I first removed it from its black soft case, I was very impressed with its sleek design.

A Waterproof 10×50 Porro Prism Binocular from Opticron

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The instrument is armored in a fetching leatherette-like substrate that really adds a touch of class to the binocular. It can be readily mated to a tripod for rock steady viewing. In the hands, it feels great, with plenty of space to wrap your hands around the large objective barrels. Star testing showed it was well collimated, with excellent control of false color. The sweet spot is satisfyingly large, with bright stars like Vega and Deneb only distorting noticeably (mostly from field curvature) in the outer 20% of the field. And even at the field stops the aberrations were not too bad. Light transmission is quite high – of the order of 87% – which is excellent for a binocular that costs just a little over $100. Further testing during the day revealed that it serves up a very bright, high-contrast image with very good control of glare. I kept asking myself, “could this really be an entry-level low light binocular?” One of the great virtues of the Opticron Adventurer T WP 10×50 is its very lightweight, thanks to its clever polycarbonate chassis. But don’t be fooled; it employs aluminum in the design of the bridge so will not bend when force is applied. The focuser is rather old-school but is silky smooth and backlash free. If anything, the rubber covered focus wheel has quite a bit of tension; but that actually works in its favor, as you’re not going to be moving it much out of focus when looking at a target in the distance. On the evening of July 28 2022 from a dark sky site in Pembrokeshire, Wales, UK, I enjoyed watching the tiniest sliver of a New Moon and over the next week, watched the waxing crescent grow in size and brightness. Under the darkest conditions the Opticron served up razor sharp images of the lunar regolith, with several dozen craters being starkly defined. Chromatic aberration was excellently controlled in the center and even when panned off-axis, this nifty 10×50 stubbornly refused to show any lateral color until the orb was placed in the outer 20% of the field. From my Bortle 4 skies, I was easily able to pick off the Andromeda Galaxy (M31), the Great Gobular cluster in Hercules (M13) in the Keystone of Hercules, and turning to Perseus now climbing higher into the eastern sky after midnight, I was treated to a breathtaking view of the Alpha Persei Association. The Double Cluster in Perseus stood out starkly against a jet black sky with hundreds of stars popping into view with a steady hand. Fellow astronomer and author Stephen Tonkin claimed that he had yet to see another binocular of this caliber under £100 UK, and after using it for a whole week, I must wholeheartedly agree with his assessment. Any drawbacks? Yes; it only comes with a 2-year warranty, so you’ll need to take special care of it if you want it to last. Close focus is just under 7 meters, so not the best birding binocular in the world or for studying butterflies in a meadow at close quarters. And it does show some flares when a bright light is placed outside the field of view. That said, none of these things matter when you’re all alone under the canopy of a dark night sky, where this economical instrument truly rocks!

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Light Cups from Celestron

The Celestron Skymaster DX 9×63. (Image Credit: Celestron)

The SkyMaster DX range of binoculars offer good, entry-level performance for those who want the best bang for buck. These classic Porro prism designs come in two configurations both possessing a 7 mm exit pupil; a 8×56 and a 9×63. These Chinese-made binoculars are fully multicoated with quality BaK4  prisms. They have a smoothly operating large center focus wheel and are water and fog proof. Both models exhibit very good eye relief too (18 mm and 17 mm, respectively), which is music to the ears of eye glass wearers. And unlike older models which featured simple soft  rubber eyecups that can be folded down, these SkyMasters come with modern twist up eyecups as well as thick, black rubber armoring to protect against the elements and accidental knocks in the field. The 8×56s will focus no closer than about 7.5 meters. That’s enough for most terrestrial applications. At 5.8 degrees, the Celestron’s field of view is decidedly mediocre compared with other brands but it’s wide enough to get a satisfying sense of perspective of the landscape. And at a street price of about $210, they’re a good bargain. Just make sure that they arrive in good collimation though. If you buy these binoculars from large outlets like Amazon, there is a decent chance that the barrels will be knocked out of alignment. Remember also to factor in their weight. At just over 1 kilo, this won’t be an instrument that you can handhold for very long periods of time, so it’s always best to have a tripod or monopod handy to afford you some more stability. If you want a little more magnification at the expense of portability, why not consider its big brother; the SkyMaster DX 9×63. This is an excellent binocular if you require that little bit more reach but lose some portability (it’s 1.25 kilos) and field of view (5 degrees). Optically, the SkyMasters offer very good and bright images which are tack sharp in the middle but become progressively blurrier as one moves off axis. Still, they remain popular because of their low cost and the strong three-dimensional views only Porro prism designs can deliver.

Great Bang for Buck from Delta Optical

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Great Bang for Buck from Delta Optical

The Delta Optical Titanium 8×56. (Image Credit: Delta Optical)

The Poland based sports optics company has earned a good reputation among hunters for their excellent value for money binoculars that offer the user good ergonomics and optics at prices that won’t break the bank. One of their products; the Titaniun 8×56 is one such example. This large roof prism instrument features fully multicoated optics and phase corrected Schmidt-Pechan roof prisms in a fully waterproof and nitrogen purged rubber armored aluminum chassis. Weighing just 990 g, the Delta Optical 8×56 has an open bridge design for better gripping and very well-­made twist up eye cups offering several positions, and with its generous eye relief of 24 mm even those who wear eyeglasses will be able to see the entire field. Independent tests showed its light transmission to be very good – of the order of 88%, courtesy of its enhanced aluminum mirror coatings. A right eye diopter ring allows you to adjust your eyes to get optimal sharpness, but users report that it moves a bit too loosely to hold its position in the right place for long. The field of view is decent: 6.8 angular degrees and owners unanimously report good sharpness all the way to the edges. Glare suppression is also excellent. Of course, the lack of any ED glass in this model does show up some color fringing on high contrast objects but if the intended use is low light observing, you’ll not be able to make out much. Some have criticized Delta Optical’s claim of it being made in Poland. The truth is that it’s probably made in China and the resulting units are dispatched to Poland where quality inspection checks are made. Only those that pass some basic optical and mechanical tests are then sent out to retailers. Still for a retail price of just $300, that’s about all one can expect.

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A Tough Low Light Binocular from Helios

The Helios Stellar II 7×50. (Image Credit: Optical Vision Limited)

Helios, a company trading under the ownership of UK-based Optical Vision Limited, produce a very well-endowed 7×50 binocular, the Helios Stellar II. Covered in a dark green and black rubber armoring, the Helios Stellar II 7×50 is built like a proverbial tank with its tough magnesium alloy chassis. The optics are fully multicoated and contain quality BaK4 prisms delivering an overall 85% light transmission. The eyepieces are individually focusing and deliver a very comfortable 20 mm eye relief. The Helios Stellar II delivers a well corrected field of 7.2 degrees and a light transmission of 85%. Such a well-built binocular comes at a price though – in this case, weight. This 7×50 tips the scales at a hefty 1.15 kilos. This is a binocular that will work in all weathers with its o-ring sealed and nitrogen purged interior. BBC Sky at Night Magazine reviewed this instrument back in August 2020 and gave it a four-star rating. Points were only deducted for the small amount of distortion creeping in near the field stops. I’d say it’s a great bargain at £169 UK.

Fujinon Anyone? The Fujinon FMT-SX 7×50 is a big and solid pair of binoculars from the top-of-the-­ range series of this renowned producer which also includes the following models: 8×30 (most likely not produced any more), 7×50, 10×50, 10×70 and 16×70. All of these instruments are equipped with huge Porro prisms and flat field eyepieces for superlative edge-to-edge sharpness. The binoculars meet US military specifications regarding ruggedness and resistance against pressurized water –according to M24

A Big Roof Prism Binocular from Hawke

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specification they are shock-proof and also fully waterproof. Their lenses and prisms are digitally designed, feature BaK-4 glass and fully multi-coated using special EBC (Electron Beam Coating) techniques which allows as much as 99.9% of light pass through one air-to-glass surface. Such an antireflection layer reduces internal reflections and flares. Like most Porros, these Fujinon’s binoculars don’t employ ED glass but still deliver top-notch images. According to the producer the light transmission for the whole instrument can exceed even a very high level of 95%, making it one of the most efficient light buckets out there. The binoculars of this series are sold in two versions: the FMT-SX and the FMTR-SX.  The latter is additionally rubber-padded but both remain completely waterproof, and nitrogen filled. Buyers get a hard case, a strap, caps and a cleaning cloth in the accessory kit. The binoculars retail for about $700 and come with a 10-year warranty.

A Big Roof Prism Binocular from Hawke

The Hawke Endurance 8×56. (Image Credit: Hawke Sports Optics)

The 8×56 configuration is now a popular choice for low light glassing, particularly in the compact roof prism models now being made. The UK-founded sports optics Hawke, manufacture a good, entry-level model for under $300. Called the Endurance 8×56, out of the box they are a hefty pair, weighing in at 1005 g. They’re very well made with a strong polycarbonate chassis covered in a good, tactile rubber armored body in British racing car green. The armoring is textured on the sides of the chassis where the hands naturally hold and thumb depressions on the inside. The twist-up eyecups provide a decent 15 mm of eye relief, with multi position are very comfortable on the eye socket. They come with tethered eyepiece and objective

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covers, that attach to the body of the bins. The strap is decent quality too, made from a strong padded neoprene substrate, with a springiness to it, to counter the weight of the instrument. Like most entry level roof prism binoculars today, the Hawke Endurance is fully water and fog proof. An average quality soft carry case and a cleaning cloth complete the package. Optically, the Endurance 8×56 is fully multicoated with phase corrected BaK4 roof prisms delivering a decent field of view of 6.7 angular degrees. Central sharpness is impressive with very little false color. Moving off axis also yields good performance, but you can see some coma, astigmatism and field curvatures near the field stops. Glare is quite well controlled; a good sign of decent baffling and the application of multi-layer antireflection coatings applied throughout the optical train. For such a large binocular, its close focus is quite impressive; with a reported measurement of just 2.3  m. Their low light performance is excellent, noticeably brighter than a 7×50, owing to the instrument’s larger objective lenses. They are also terrific to use for star gazing, though they are quite heavy to use for prolonged observations. Thankfully the Hawke Endurance 8×56 can be mated easily to a tripod to steady up those views.

Engage Your Passion with a GPO Passion 8×56

The GPO Passion 8×56

In a previous chapter, I covered some excellent quality binoculars from the new German-based company, German Precision Optics (GPO). In these reviews I was

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very impressed with the outstanding build quality of their products, not to mention their excellent optical quality. But GPO have not just settled on securing a solid niche in the compact and mid-sized binocular market, they have also developed larger aperture models specifically designed for low light work and astronomy; enter the GPO Passion 8×56 and 10×56 models. I acquired an 8×56 unit on loan from Steve at First Light Optics for testing and evaluation, and I must again say how delighted I was to see that GPO really are delivering excellent value for money in this competitive corner of the sports optics market. The instrument arrived in a beautiful presentation box. The binocular was set rigidly in place in the cut-out foam section and lying adjacent to it, the beautifully designed hard case to store the instrument. Inside the case you’ll find the usual accessories; padded neoprene logoed neck strap, carrying strap for the case, a comprehensive multi-language instruction manual and microfiber lens cleaning cloth. If you take the case out, you’ll also find the 10-year European warranty card for the instrument. The GPO Passion 8×56 is one chunky instrument and you immediately get the feeling of quality the second you prize it from the box. This larger instrument is a scaled-up version of the 42 mm and 32 mm Passion ED binoculars, with a magnesium alloy chassis overlaid by a nicely textured black rubber armoring. Tipping the scales at 1257 g, this is not an instrument that many would happily trek with all day; unless you’re Hulk Hogan. It’s designed to be used for hand-held viewing for short periods of time but mostly for tripod mounted activities, such as hunting in low light or for watching the stars The focus wheel is covered in a textured black rubber which is easy to grip, rotating just over one full revolution anti-clockwise from nearest focus to just beyond infinity. Though I have reported a small amount of free play in a smaller 10×32 GPO Passion ED in a previous review, I was pleased to see that there was none apparent on the focus wheel of this 8×56 model. A closer inspection of the shape of the barrels reveals the nature of the prisms used in this binocular; the large Abbe-Koenig roof prisms that deliver higher levels of light than standard Schmidt-Pechan prisms incorporated into the smaller GPO models. It’s these Abbe-Konig prisms that contribute to the weight and the length of this binocular, but it’s all the more remarkable that this optical design is incorporated into this low light binocular at this price point. These prisms are notoriously difficult to make well and are usually only found in instruments costing at least twice as much as this 8×56 costs. The beautifully machined twist-up aluminum eye cups are covered in soft rubber for very comfortable viewing. Four positions are offered to suit most anyone’s requirement for eye relief. I’ve said it before and I’ll say it again: these are amongst the best eye cups ever designed by any binocular manufacturer, period. I was easily able to access the entire field of view with eyeglasses, so absolutely no worries there. The diopter adjustment is accessed by turning a ring under the right ocular. It moves smoothly but with considerable tension, ensuring it won’t easily be moved out of position in field use. The proprietary broadband multi-coatings present with a fetching purple hue in broad daylight and are immaculately applied. Viewed head on, they make the lenses

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almost disappear. The instrument is dry nitrogen purged internally and o ring sealed to prevent fogging up of the internalized optics. It is also waterproof, but GPO don’t mention to what degree it will withstand water immersion. The reader may be surprised to learn that, unlike the smaller ED models, the larger 8× and 10×56 models do not contain ED glass. GPO believe it wasn’t necessary to incorporate extra low dispersion glass in these models because their main use was in low light conditions, when seeing any color in a given target becomes difficult to discern, so there would be little advantage in employing an ED element which would have significantly increased its production cost. Having enjoyed many hours testing the instrument both in low light situations and under the stars at night, I can only agree with their design philosophy, as I shall report on a little later. All in all, the build quality and ergonomics of this 8×56 are exemplary, and quite in keeping with their other models I’ve reviewed from both their ED and HD lines in the past. My first optical test involved shining a bright light source into the binocular and examining the images produced. I detected a few minor reflections but noting too intrusive. Diffraction spikes were very subdued and there was no diffused light around the light source indicative of good homogenous glass. Turning the binocular on a bright streetlamp after dark did show a few minor internal reflections but by and large I was quite happy with the result. Placing the lamp just outside the field of view showed very little in the way of stray light intrusion; an impressive result compared with many other similar tests performed on other binoculars. Examining the exit pupils also yield good results. The large 7 mm exit pupils were perfectly round with little in the way of extraneous light around them. I did pick up some light leaks well away from the pupils though, a consequence of using Abbe Koenig prisms perhaps? Thankfully they appeared to make no material difference to the images garnered by the instrument. Testing the binocular out on a bright sunny afternoon revealed very impressive images right from the get-go. The image is razor sharp inside its very large sweet spot, with only a small amount of softening of the images noted near the field stops. Contrast is excellent. Scanning a large swathe of trees at the edge of a forest proved to be a very comfortable experience and extremely easy on the eyes, with no blackouts or the rolling ball effect kept well under control, courtesy of a modest amount of pincushion distortion near the field stops. Colours are very vibrant in this big glass, and I immediately noted the warm tone of the images – very much like those I reported on the smaller ED and HD models. Indeed, I had long wondered whether this warm colour tone was a manifestation of the ED glass utilised in the smaller GPO binoculars. Clearly this was not the case; those warm tones were also present in this non-ED model! Glare suppression is excellent in the GPO Passion 8×56. It stubbornly refused to show any on bright autumnal days, and also on grey overcast days in the open air. Veiling glare was also exceptionally well suppressed in this instrument to; a testament to the excellent coatings applied to the lenses and prisms, as well as the baffling used in the instrument. Close focus was also very surprising. I measured it at just 2.14 m, so slightly better than the advertised 2.3 m. I consider that amazing for

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such a large glass. Chromatic aberration was also very well controlled in this unit. There is a small amount visible on high contrast targets, such as imaging the side of a telephone pole against a bright overcast sky. Lateral (off axis) colour is a bit more pronounced in this large aperture instrument though, but I felt it was perfectly acceptable given the modest price tag of this instrument. Overall, I would rate the daytime images as quite excellent. Testing its low light capability, I compared and contrasted the views through my excellent Opticron Imagic TGA WP 10×50 Porro prism binocular with those garnered by the GPO 8×56. I found the views very comparable until about a half hour before sunset on September evenings, with the 8×56 pulling noticeably ahead on selected targets under hedgerows as the last rays of sunlight dipped below the horizon. By about 40 min after sunset, the 10×50 was really struggling in comparison with the views through the 8×56. I was dying to find out how the GPO Passion 8×56 would perform under a dark, clear sky at night and I wasn’t disappointed! In fact, the views were absolutely stunning! The very generous field of view effortlessly frames wonderful star fields. Bright stars such as Vega and Aldebaran are rendered in their natural colors. Chromatic aberration was a non-issue in the inner 50% of the field, and only showing mild splashes of bluish purple as the stars were moved to the outer part of the impressively large field of view. Fainter stars were examined to see how well they maintained their pinpoint sharpness. I was very pleased to see that they remained impressively small and tight across about 75% of the field, with some mild field curvature begging to show up thereafter. Only in the last 10% of the viewing portal, could I make out some a small amount of astigmatism and coma creeping in. I was genuinely surprised how long I could hand hold the binocular while scanning the Milky Way through Cygnus, Perseus and Cassiopeia. The low power of 8× definitely helps in this regard. For more serious studies though, I resorted to mounting the instrument on a lightweight monopod. Views of the Pleiades and Hyades in Taurus were simply stunning, its very high light throughput presenting very faint stars quite invisible to a 42 mm model, with their various hues showing up beautifully. In fact, this instrument threw up some of the best binocular views of the heavens I have personally experienced. I enjoyed exploring many early autumn open clusters, such as the M36, 37 and 38 spanning the mid-section of Auriga. M 34 in Perseus and the great globular cluster in Hercules (M13) stood out like proverbial sore thumbs in this large binocular light bucket. The Alpha Persei Association and Double Cluster in Perseus were breathtaking in this binocular too. Rising up in the wee small hours of late September, I was treated to some extraordinary views of Orion; with the white and blue-white Belt stars shining brilliantly and below them, in the famous Sword Handle of the celestial Hunter, the magnificent Orion Nebula blazing forth across the light years. The excellent light gathering power of the GPO 8×56 allowed to follow much fainter tendrils than I could make out in a optically excellent 7×50 Porro prism binocular, though I must concede to yearning at times for a comparative look through its higher power sibling; the 10×56, which probably would have knocked my socks off. All of these experiences only consolidated what I had seen during the day: this is an excellent low light/astronomy binocular that would satisfy the most discriminating of observers.

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So, here we have yet another GPO binocular offering exceptional ergonomics and really good optics for a very decent price. I say this in light of a cursory examination of other 8× or 10×56 models, built around Abbe Koenig prisms. The Kite Cervus 8×56 has very similar specifications and pricing to the GPO Passion. Indeed, it appears to be almost identical to the big GPO glass. I was alerted to this while discussing the GPO binocular on Birdforum. In which case, my advice would be to choose the one that is least expensive and buy from a reputable dealer. The Zeiss Conquest HD 8×56 (discussed below), for example, has a build quality quite comparable to the GPO Passion, but its field of view is slightly smaller (7.1 degrees), its weight slightly heavier (1265 g), its close focus distance much longer (3.5  m), and possess a light transmission of 90%, broadly the same as the GPO Passion even with ED glass. But that instrument retails for more than twice the price of the big GPO glass! Or consider the fluorite containing Maven B5 10×56 costing a few hundred pounds more than even the Zeiss Conquest HD. Seen in this light, the GPO Passion 8×56 offers tremendous bang for buck and absolutely deserves great success in the sports optics market today.

Low Light Excellence from Zeiss

The Zeiss Conquest HD 8×56. (Image Credit: Zeiss Sports Optics)

The highly lauded Zeiss Conquest HD line of binoculars not only is confined to compact and mid-sized binoculars but also includes a beautifully designed 8×56 model for those who want uncompromising performance in low light situations. This is one

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big binocular with a length over 8 inches and nearly 6 inches wide. Like its smaller siblings, the Zeiss Conquest HD 8×56 is packed full of high technology features. Introduced in 2014, this model represents a departure from the Schmidt Pechan roof prism found in smaller Zeiss Conquest models, replacing these with the greater light transmission of Abbe-Koenig prisms, which is immediately evident by examining the shape of its barrels. The large 56 mm objectives are equipped with the finest Schott ED glass and Zeiss apply their proprietary T* coatings throughout the optical train, ensuring an overall light transmission of the order of 93%. And like the smaller Zeiss Conquest models, the outer lenses are coated with the excellent  Zeiss Lotutec layer applied to the outer lenses which repels water and dirt. The field of view is good but not outstanding at 7.1 angular degrees but its great edge-to-­edge sharpness definitely makes it seem wider. The Zeiss Conquest is waterproof to a depth of 4 meters and is designed to operate at temperatures ranging from −30° C to+63° C and the dry nitrogen inside the chassis ensures it will not fog up in colder conditions. As you’d expect though, all of these optical goodies and large lenses render it quite heavy – 1265 g to be exact. Ergonomically, this big binocular feels great in the hands with its thick, non-slip black rubber armoring. The twist-up eye cups have four settings and with 18 mm eye relief, one can easily engage with the entire field of view using eyeglasses. Buyers get a rain guard and lens caps, a strap and a hard case with a strap of its own in the box. The product comes with a 10-year guarantee period. That said, as you might expect, a binocular like this doesn’t come cheap. Expect to pay $1600 for a new package.

The Ultimate Choice for Low Light Viewing?

The Swarovski SLC 8×56. (Image Credit: William Lewis)

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If you’re looking for the ultimate in low light glassing, you’ll not go wrong with the Swarovski SLC 8×56 WB.  What does SLC stand for? Slim, Light, Compact. That might be true of the smaller SLC models but certainly not this one! This amazing binocular delivers 93% of the light it gathers with its objectives to the eye. It’s field of view (7.6 degrees) is very wide and beautifully corrected. All of Swarovski’s state-of-the-art technologies are built into this wonderful low light binocular. Fluorite containing objective lenses all but eliminate color fringing, Abbe-Koenig prisms maximize light transmission, state-of-the-art eye cups provide a supremely comfortable 23 mm of eye relief and the tough Swarovski green rubber armoring affords a wonderful grip in your hands. Unlike the Zeiss Conquest and GPO Passion ED models previously discussed, the diopter setting is built into the focuser. To adjust it pull the focus wheel out and once you’ve made your adjustment, push it back in again. The focus wheel on the big SLC is buttery smooth with absolutely no backlash or free play. And of course, this premium optical instrument comes fully water and fog proof and those hydrophobic coatings on the outer lenses ensures you’ll never miss a thing even in cold, wet or icy weather. Compared with the EL and NL Pure range, the SLCs show a little more field curvature, meaning that the edges of the field are a little bit more blurred but it’s never enough to cause alarm. All of this technology doesn’t come cheap though. Expect to fork out $2500 for the privilege of owning one. While low light binoculars are most used by hunters and amateur astronomers, clever electronic engineers have devised very high-tech binoculars that can measure distances, inclinations and much more at the touch of a button. These so-called range finding binoculars will be the subject of the next chapter.

Chapter 7

Range-Finding Binoculars

Not only do binoculars deliver crisp images of the natural world and the heavens above, but they are also indispensable tools for hunters, archers and a wide range of military applications. In this chapter we’ll take a closer look at range finding binoculars; instruments that can deliver accurate information about the distance to your target. They can also provide state-of-the-art ballistic information, which can greatly improve the accuracy with which a target can be hit, removing nearly all the guesswork usually involved in their acquisition. There are two main kinds of range-finding binoculars; one that make use of a reticle scale and those that use a laser beam. The least expensive binoculars with rangefinders are those that use a marked reticle which you see in the view when looking through the eyepiece. Whilst they are in most cases substantially cheaper than laser rangers, you should not consider them to be inferior, rather just different and in the right applications, a reticle rangefinder can often be the better option: When you look through a reticle range finding binocular, the fine lines with scale markings you see in the field of view can either be digitally displayed or are physical markings in the view usually made with very fine fibers. They are similar to the crosshair that you see when looking through a rifle or finder scope on a larger telescope, and the scale that is displayed enables you to work out the distance from the object either using a simple formula (you can also work out the height or width) and/or by a system of silhouettes that enable more swift ranging without calculations. The mil dot reticle is another variation, which uses dots instead of lines and are another popular choice for long range hunters and target shooters. Some range finding binoculars will also have a number of different sized silhouettes marked in the view and all you then need to do is match them to the object to get an idea of the distance which is marked under the silhouettes. Apart from costing less than a laser rangefinder, the main advantage of ranging with a reticle is that it can be used over longer distances, and which is why it is most commonly used on marine binoculars or for long range target/hunting optics. Many military binoculars will also use this method for long range uses and because there will often be times when a © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_7

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laser is not ideal as it can give your position away. In addition, because this type of range finding devices do not generally need batteries to operate, they can be relied on in most any circumstance one finds oneself in. By far the most common and easy to use ways of estimating distance is to use a laser rangefinder. My son is a keen golfer and uses a simple monocular range finder to help him make informed decisions about which club to use when executing his next shot. The rangefinder has a sighting tube used to accurately focus on your target. It also has a built-in laser which emits an infrared laser beam that moves at the speed of light. The laser beam gets reflected off the target and a portion of the original infrared light is sent back to the range finder where a high-speed clock measures the travel time. Multiplying the speed by the time and then dividing by two provides the distance to your target.

The principle behind the laser rangefinder technology. (Image Credit: Wiki Commons)

An infrared laser beam is chosen since it lies well beyond what the human eye can detect. The exact same principle applies to binocular range finders. Gone are the days when you have to carry a small range-finding monocular and separate binocular, which saves the user time. Another advantage is that the binocular view involves using both eyes to more accurately lock onto your target. It will also have a significantly wider field of view, so you put more of the action before your eyes. Are there any downsides to using a binocular rangefinder? Some would say yes! They will say that the electronics built into the binocular will compromise the optics to some degree, by reducing the contrast in the image. That said, if properly executed, the loss in visual acuity should be minimal. So now, let’s take a look at some of the models available on the market.

The Bushnell Fusion X 10×42

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The Bushnell Fusion X 10×42

The Bushnell Fusion X 10×42. (Image Credit: Bushnell Sports Optics)

This sub $700 instrument from Bushnell comes with mixed bag of nice features. First off, the 10×42 optics are fully multicoated but instead of BaK4 prisms, the Fusion X has the inferior BK7 roof prisms. They are phase and dielectrically coated though, so should still produce bright images. The field of view is quite narrow for a 10×42 too: just 5.8 angular degrees. The Bushnell is waterproof (IPX7) and nitrogen purged so shouldn’t fog up while being used in adverse weather conditions. In addition, the outer lenses on the Bushnell Fusion X has the company’s proprietary EXO-Barrier coatings that repel water and dirt helping keep your optics clear at all times. The range finding button is found on top of the bridge and can accurately measure distances to a target up to about 1 mile in the distance. Its in-built Angle Range Adjuster can also give you accurate distance measures if you’re glassing downhill or uphill of your desired target. It also gives you drop compensation data in inches or millimeters. An LED display allows you to accurately center the target in low light conditions when hunters are most active. Of course, all of that built in technology adds to the weight of the instrument (900 g). The Fusion X 10×42 is powered by a single CR2 battery and is covered by Bushnell’s Lifetime Ironclad transferable warranty.

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A Compact Rangefinder from GPO

The GPO Rangeguide 2800 10×32. (Image Credit: GPO)

Most binocular range finders on the market today have either 42 or 50 mm objective lenses, making them rather heavy and bulky. But the new firm German Precision Optics (GPO) has bucked that trend by introducing compact 8× and 10×32 range finder. Called the Rangeguide 2800 8×32 (there’s also a 10× model), this neat little binocular is packed full of quality features that many hunters will appreciate. First let’s look at the binocular. Weighing in at just 700 g, the GPO Rangeguide 2800 8×32 features the same high-quality optics found in their Passion ED line and sports a wide field of view – an impressive 7.7 degrees. Eye relief is excellent at 18 mm, so you’ll be able to enjoy that large field with glasses. Featuring a quality magnesium alloy chassis, it’s waterproof and fog proof and just like the regular GPO binoculars, their beautifully machined twist up eyecups are amongst the best in the industry. Close focus is advertised at 8  m and features a diopter compensation range of+/−4. Now, let’s look at the electronic features. The Rangeguide 2800 can measure reflective targets at an impressive 2.8 kilometers. The distance to a tree can be measured at 1 kilometer and a deer at 800 m using a red OLED display with a choice of 9 brightness levels. Range measurements are impressively fast; you can take up to 4 every second! Other features include accurate measurements of slope, ambient temperature, air pressure and humidity, all powered off a single Cr2 battery. If an 8× magnification is not enough for you, GPO also offer a 10×32 model too. What’s remarkable about these compact Rangeguide 2800 models is how streamlined they are. Unlike many other binocular rangefinders, you wouldn’t know they have all those sophisticated electronics inside. Usually, it’s a dead giveaway with a large protrusion on top of the binocular, but not on these GPOs! What is particularly impressive is you get the same high-quality accessories that come with their regular binoculars including a choice clamshell case, a wide neoprene neck strap with the GPO logo, a microfiber lens cleaning cloth, ocular and objective lens covers and an impressive 10 year warranty. The price is very good too – you can get the 8× or the 10×32 models for about $900.

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One downside of using a 32  mm model is that it has limited light gathering power, making them especially suitable for mountain hunting which mostly occurs during the day when the light is good and strong. But for hunting in low light conditions GPO also offer two larger models in the Rangeguide 2800 8× and 10×50, which provide much brighter images needed at dusk and dawn owing to their larger exit pupils and bigger objective lenses which retail for about $1250.

Laserforce Technology from Nikon

The Nikon Laserforce 10×42. (Image Credit: Nikon Sports Optics)

The Nikon Laserforce is a 1900-yard rated laser rangefinder in a sturdy 10×42 binocular with a current street price from $1000–$1200. You’ll be able to get quick and reliable ranges from 10 yards right up to, and over, the 1900-yard rating. The angle compensation mode is accurate and reliable right down to the ranges common to archery – 10–60 yards. The CR2 battery lasts quite a while, and operates effectively right down to temperatures as low as −17° C. The optics are usable but apparently have some issues. The instrument has a decent 6.1-degree field of view but some owners have reported substantial pincushion distortion and distorted images towards the edge of the field. While sharp and bright enough for serious use, it’s got a fairly shallow field depth, which necessitates frequent re- focusing. Color fringing is apparent in the center of the field and becomes quite distracting near the field stops. One report I read claimed that the left and right barrels had a different color bias, with the left barrel displaying a warm, yellow tint, while the right barrel (where the display screen is seen) had a cold blue hue which made merging the images a bit more difficult. The build quality is solid and robust though. Perhaps that’s the reason why Nikon offer a lifetime warranty on the optics as well as the electronics, and you can see why when you hold the

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instrument in your hands. The good news is that the Laserforce retails at about a third of the price of its European competitors or compared to purchasing a binocular and rangefinder separately. Hunters requiring the convenience of a range-finding binocular, but don’t care particularly for the quality of the optics will find this a prudent choice. The Nikon Laserforce retails for about $1200.

A Furious Performer from Vortex Optics

The Vortex Fury HD 5000. (Image Credit: Vortex Sports Optics)

On a family vacation to Wigtown in southwest Scotland I was given the opportunity to test drive the Vortex Fury HD 5000 10×42 range-finding binocular. It was owned by our holiday cottage host, himself a keen hunter. I remember how well built it was, with its thick rubber armoring and its hefty weight, but what I most remember is its impressive optics, with its decent field of view of 6.1 degrees. The Vortex Fury HD 5000 has a silky smooth focuser and excellent twist up eye cups, not to mention its ability to accurately measure the distance to a target off in the distance a few hundred yards away near the Solway Firth. In short, I could easily see why this high-tech wonder from Vortex was one of the best-selling serious binocular rangefinders on the planet. The rangefinder present in the Vortex Fury 5000 rangefinder is second-generation instrument that boasts the lightest, smallest, and powerefficient modules in all rangefinder types. They can conveniently measure targets up

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to 5000 yards with high accuracy. Its range is ultra-fast and highly efficient, which is useful when you want to locate moving targets. The Vortex Fury 5000 comes with different preset target modes, including the Best Mode and the Last Mode. The Best Mode provides you with the target range with the strongest range results, while the Last Mode provides you with the farthest distance while scanning and panning. The Last Mode will work better when your target is behind a group of rocks, trees, or brush. On the other hand, the best mode is particularly suited to most hunting or shooting situations. With these Vortex binoculars with rangefinder, you can easily spot a reflective objective at 5000 yards, a deer at 1600 yards, or a tree at 2000 yards. In addition, this powerful rangefinder for your hunting excursions can produce angle compensated results with its HCD (Horizontal Component Distance) mode. The HCD sensor in the image quickly calculates the right elevation to give you an accurate reading of your prey. The Vortex Fury binoculars are endowed with quality optics with their HD optical system that reveal high-resolution images mostly devoid of chromatic ­ ­aberration. These binoculars come with multi-layered phase-corrected dielectriccoated prisms to ensure the user is provided with accurate colors with very good contrast. Vortex has used its trademark XR multi-coating on both prisms and lenses for even brighter results and  contrast. With these features, you get high-­quality images even when the light begins to fade. The outer lenses are treated with Vortex’s ArmorTek coating to prevent scratches. As you’d expect, the Vortex Fury HD 5000 is o ring sealed and is thus fully waterproof and purged with dry nitrogen gas to deliver reliable performance in foggy and rainy environments. A single CR2 battery allows for up to 4000 range measurements before its needs replacing. Of course all of that technology counts for very little unless the ergonomics are not up to scratch, but rest assured, Vortex have done their homework here too. The twist-up eyecups have several detents and plenty of eye relief for eyeglass wearers. The textured matte rubber armoring is easy to grip, even with gloves on and its shock and recoil proof. And tipping the scales at just over 900 g, it can be transported with relative ease for hours on end. The Vortex Fury 5000 10×42 retails for about $1200, making it excellent value for money and don’t forget the company’s exemplary no fault VIP warranty, which ensures that if anything happens to your investment, Vortex will either repair or replace it with no cost to you. The reader will note that Vortex also market their sister range-finding binocular in the Fury HD 5000 AB 10×42, which comes with Applied Ballistics. This is a third-party program that provides unbiased ballistics information to assist you in various long-shooting applications. The ballistic features include wind speed, temperature, pressure, and profile sections. The Fury HD AB 10×42 model is ideal for long-range shooters because it takes out the guesswork by providing highly accurate readings of the target object. Expect to pay an extra $500 more for these features when you’re going shopping.

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High Technology Range Finding from Meopta

The Meopta Optika LR 10×42 HD. (Image Credit: Meopta Sports Optics)

The Meopta Optika LR range finding binocular were introduced in 2021 and was designed for hunters, shooters, and outdoor enthusiasts who demand the highest level of precision and accuracy in their optics. The Optika LR 10×42 HD binocular offers up an impressive 6.7 degrees of true field and is equipped with an advanced rangefinder that can accurately measure distances up to 2800 yards. It features a scan mode for continuous measurements, as well as a ballistic mode that calculates the bullet drop compensation based on the selected caliber. The binoculars feature high-definition (HD) optics with fluoride lenses that provide exceptional clarity and resolution, even in low light conditions. The lenses are also treated with Meopta’s proprietary MeoBright coatings, which reduce reflections and glare for better image contrast and brightness. Tipping the scales at 900  g, the Optika LR 10×42 HD features an ergonomic design that is comfortable to hold and use for extended periods of time. The rubber armor coating provides a secure grip, even in wet or slippery conditions. The instrument is nitrogen purged and sealed to prevent moisture from entering, making them waterproof and fog proof. They can withstand immersion in water up to 1 meter deep for up to 30 min. The binoculars feature a ballistic reticle that can be used for ranging and holdover adjustments. The reticle is located in the left eyepiece and can be activated by pressing a button on the top of the rangefinder housing. The rangefinder display can be customized with different color and brightness settings to suit different lighting conditions and personal preferences. The Optika LR binoculars are powered by a single CR2 battery, which provides up to 3000 measurements on a single charge.

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In summary, the Meopta Optika LR range finding binoculars are a high-­ performance optic that delivers exceptional precision and accuracy in a rugged and durable package. All of this European technology can be had for $1900.

The Amazing Leica Geovids

The Leica Geovid 10×42 R. (Image Credit: Leica Sports Optics)

Leica has long been a leader in the optical part of sports optics, but the reader may be surprised to know that the same company led the way in laser range-finding optics when they brought the first such devices to market back in 1992. Since then, Leica have been world leaders in this new technology, producing more models than all other manufacturers to date. Indeed, at the time of writing, Leica offer no less than four range finding binocular series to suit the demands of discerning customers. Here we’ll take a closer look at two Leica models, the Geovid 10×42 R and the more expensive Geovid 3200.com The Leica Geovid 10×42 R represents the company’s best bang-for buck range finding binoculars, combining great optical performance with reliable range finding technology. Launched in 2016, the basic design of the Geovid R has been around since 2004 and represents the upgraded HDR model. Featuring high quality Schmidt-Pechan roof prisms in a completely water and fog proof housing, it’s excellently armored with thick black rubber. Produced in Leica’s Geovid R factory in Portugal, it tips the scales at 950 g, is 17 cm in length and 14 cm in width. The reader will note that the Geovid 10×42 R comes either as a yard rangefinder or a meter rangefinder, so is not capable of converting from one to the other. The Leica Geovid 10×42 R is a binocular that offers both superior optics and advanced ranging capabilities. Here are some of its key features: The Geovid 10×42

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R offers high-quality optics, including a 42 mm objective lens and a powerful 10× magnification, providing a bright and clear image even in low light conditions. The instrument features an integrated rangefinder that can measure distances up to 1100 yards (1000  meters) with an accuracy of+/−1 yard (1  meter). The rangefinder includes a high-contrast LED display that provides clear and easy-to-read distance measurements. Just like all Leica binoculars, the Geovid 10×42 R is designed for comfortable use, with a robust and lightweight aluminum housing, an ergonomic bridge, and a non-slip rubber coating for a secure grip. The twist-up eye cups afford 19 mm of eye relief, so plenty enough for eyeglass wearers. It’s built to withstand harsh weather conditions, with a waterproof and fog-proof construction that ensures reliable performance in any environment. The Geovid 10×42 R includes additional features such as a tripod mount, a diopter adjustment, and a wide field of view for easy tracking and observation. The 8×42 model offers a field of view of 7.13 angular degrees, while the 10×42 serves up a 6.3 degree field and retail for about $1400 and $1600, respectively.

The Leica Geovid 3200.com. (Image Credit: Leica Sports Optics)

Leica’s Geovid 3200.com represents the company’s most advanced range finding technology designed for hunting, outdoor and sports enthusiasts. Three models are available in this series, 8× and 10×42 and a larger 8×56 instrument, with fields of view of 7.44, 6.5 and 6.75 degrees, respectively. Here are some of the key features of these binoculars: The Geovid 3200.com binoculars feature state-of-the-art optics, including a 42 mm or 56 mm aperture models with an 8× or 10× magnification, providing a clear and bright image even in low light conditions. The instrument includes a powerful rangefinder that can measure distances up to 3200 yards (2900 meters) with an accuracy of+/−0.5 yards (0.5 meters). The rangefinder can also provide angle-­ compensated distance measurements for uphill and downhill shots. The Geovid

Top Range Finding from Zeiss

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3200.com binoculars feature an advanced ballistic system that allows the user to input their rifle’s ballistic data, including bullet type and caliber, and provides holdover or turret adjustments for precise shots at longer distances. The rangefinder includes an LED display that provides clear and easy-to-read distance and ballistic information. The Geovid 3200.com binoculars are equipped with Bluetooth connectivity, allowing the user to connect to the Leica Hunting App and input custom ballistic data. The Geovid 3200.com binoculars are designed for comfortable use, with a lightweight and durable magnesium housing, an ergonomic open bridge configuration, a non-slip rubber coating for a secure grip, as well as some of the best twist-up eyecups in the industry. These instruments are built to withstand harsh weather conditions, with a waterproof and fog-proof construction that ensures reliable performance in any environment. The Geovid 3200.com binoculars include additional features such as a tripod mount, a diopter adjustment, and a wide field of view for easy tracking and observation. They also come with a carrying case and a neck strap for easy transportation. These state-of-the-art instruments command a hefty price tag. Both the 8× and 10×42 models are priced at about $3100, while the larger 8×56 model commands a price of $3600.

Top Range Finding from Zeiss

The Zeiss Victory RF binoculars. (Image Credit: Zeiss Sports Optics)

Not to be outdone by the Leica, Zeiss has also brought to market their own range finding binoculars. The Zeiss Victory RF binoculars are a premium series of binoculars designed for birdwatching, hunting, and other outdoor activities that require a high level of precision and accuracy. They are made by the German company Carl

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Zeiss AG, a leader in the optics industry, and are known for their exceptional quality and performance. The Victory RF binoculars come in four models: 8×42, 10×42, 8×54 and 10×54. They feature high-quality Schott HT glass and Zeiss’ proprietary T* and LotuTec coatings, which ensure maximum light transmission and crystal-­clear images, even in low light conditions. The Zeiss Victory RFs sport even wider fields of view than the Leica Geovids. The 8×42 model, for example, delivers an impressive 7.7 degree field of view, whereas the 8×54 serves up a 6.87 degree true field. The binoculars also feature a rangefinder system, which allows you to accurately measure the distance to your target with the press of a button. The rangefinder has a maximum range of up to 2500 yards, making it ideal for long-distance hunting and shooting. As you’d expect from Zeiss, these instruments are also built to be rugged and durable, with a magnesium alloy housing that is both lightweight and impact resistant. They are also waterproof and fog proof, making them suitable for use in all weather conditions. Other features of the Victory RF binoculars include a comfortable grip, an ergonomic design that reduces fatigue during prolonged use, and a diopter adjustment that allows you to fine-tune the focus for each eye. They also come with a high-quality carrying case and a neck strap for easy transport. Overall, the Zeiss Victory RF binoculars are a top-of-the-line product that combines exceptional optics, range finding capabilities, and rugged durability to deliver the best possible performance during any outdoor activity. Both the 42 mm models retail for $3700, while the 54 mm instruments are about $200 more at $3900.

The Swarovski EL Range

The first-generation Swarovski EL Range 10×42

The Swarovski EL Range

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Want the very best optics coupled to state-of-the-art range-finding technology? Many will point you towards the Swarovski El-Range. The first generation of this binocular appeared back in 2011, an updated version was released in 2015, and then in early 2021, the third generation of the EL range came to market. There were only a few things upgraded in going to the second generation EL range; a rubber eye piece cover replaced one made of plastic. The neck strap attachments were also improved. The third generation EL range incorporated several more changes including Swarovision flat field technology, a 10% wider field of view, an advanced ballistic calculator with tracking assistant and the ability to be connected to a smartphone app via Wi-Fi. The El Range 8× and 10×42 have elegant open bridge designs and tip the scales at a respectable 960 g. The twist up eyepieces are overlaid by soft rubber and offer 4 positions to accommodate the needs of those who wear eyeglasses and those that don’t. The central focusing wheel is buttery-smooth and rotates through two full revolutions from one end of its focus travel to another, offering a turning speed intermediate between that ideally suited to birders and hunters. The electronics are housed under the barrels and create prominent bulb-shaped structures that do look and feel a bit odd at first. And while other leading range finder manufacturers have managed to hide these features better, Swarovski probably went with this design feature to ensure that the electronics were kept as far away from the optics as possible, as it’s known that these can actually reduce light transmission and degrade image quality. The earlier EL Range models featured one button on the top of the bridge, but the third generation has two buttons installed; one on the right-hand-side of the bridge and another on one of the bulls on the underside of the barrels. Unlike their range of conventional binoculars where the push-pull diopter setting incorporated into the central focuser, the diopter adjustment on the EL Range binoculars is featured under both eye pieces as a prominent ring that can be pushed up, adjusted and pushed back down to lock. The latest EL range can also be mated with Swarovski’s head rest system for increased stability, just like their flagship NL Pure series of binoculars, but because it’s designed differently the head rests for the NL Pure series are not compatible with the model used with the EL Range. To attach the headrest simply remove the cap covering the battery compartment and screw it in. The waterproof chassis is constructed from Magnesium alloy and it’s purged with dry nitrogen gas to prevent any fogging up in the field. The rubber objective lens covers have been incorporated into the end of the barrels so can’t easily be lost. One of the biggest advantages of the third generation EL Range series is the introduction of Swarovision technology, based on a field flattening lens system like that used in the current EL and NL Pure line of their binoculars, which gives the user wonderful high-resolution imaging with excellent edge-to-edge sharpness. The field of view on the 10×42 EL Range is an impressive 6.84 angular degrees. And unlike many other range-finding binoculars, the optical quality is just as good as their world-class conventional binoculars. I had an opportunity to test drive the first generation EL Range 10×42 and can vouch for its exceptional optical quality. With a light transmission of 90%, the views

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are bright, sharp with excellent contrast. Indeed, while looking at a variety of targets, you very quickly forget about the fact that this is a laser range finding binocular because the images look so good. The range of measurements of the built-in laser is from 10 m all the way out to 2000 m, with an accuracy of+/−1 m up to 1500 m. Swarovski also produce an 8×42 EL range which is better for beginners since it has less handshake and delivers a more stable image. The 10× instrument is more popular with experienced hunters however since you can see more details at longer ranges. The mobile app allows the user to transfer any measurements made to your cell phone from the binoculars; very handy if you need to collect such data. In addition, the App allows you to record your location (via GPS technology) and also the location of the targets you previously ranged. If you happen to get lost, the App will point you in the direction you need to go to find the exact spot you ranged from. The advanced ballistic calculator is another excellent feature of the App which allows you to calculate the precise angle you need to shoot your target at given the temperature, air pressure and other parameters that influence the kinematics of shooting bullets. The El Range binoculars come with a beautiful clamshell case with the Swarovski logo proudly displayed, a wide and comfortable neoprene neck strap, cleaning cloth, rubber rain guard. As you might expect, these instruments don’t come cheap; expect to pay in the region of $3500 for the privilege of owning one. That completes our brief survey of the kinds of range finding binoculars available on today’s market. In general you get what you pay for but there are always bargains to be had if you keep a lookout. In the next chapter, we explore the wonderful world of astronomical binoculars.

Chapter 8

Astronomical Binoculars

Binoculars are not just useful tools for birders, hunters and nature enthusiasts, they can also serve as incredibly useful tools for stargazing and amateur astronomy. In this chapter, I’ll be taking a look at some of the key features of the most commonly used binoculars used by stargazers and their various uses. Let’s first begin with some general principles about why binoculars are so good for viewing the night sky. Many seasoned astronomers will tell you that before buying a telescope, it’s best to start exploring the night sky using binoculars first. That’s because they are very intuitive to use, are generally small, portable and lightweight and offer a wide angle, ‘zoomed out’ picture of the night sky. The average binocular used for birding will greatly increase the number of stars you are likely to see in the night sky. About 4000 stars are visible to the unaided eye from the darkest, clearest skies on Earth, but a binocular will increase this tally to 100,000 or more. The greater light gathering power and magnification a binocular affords over the naked eye will enable you to make out star colors far more vividly than you can with the unaided eye. Looking at the planet Jupiter with binoculars will show you four of its large satellites as they orbit the Giant Planet and allow you to follow their movements from hour to hour and from day to day. Faint planets like Uranus and Neptune are readily seen in binoculars if you know roughly where to look. The Moon and its glorious phase changes can be watched with great interest, where a steady hand can reveal up to 100 craters under ideal viewing conditions Coupled to this, a whole suite of so-called deep sky objects are within easy reach of even small, handheld binoculars; the Great Spiral Galaxy in Andromeda, the Pleiades and Hyades open star clusters in Taurus, the Sword Handle of Orion and the Large Magellanic Clouds in the Southern Hemisphere. Wide-angled binoculars are the dream ticket when scanning the glories of the Summer and Winter Milky Way, snaking its way across the sky from horizon to horizon. They also serve as excellent tools for watching lunar eclipses, earthshine, and tracking artificial satellites.

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_8

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How much do you gain with a binocular over viewing a telescope of the same aperture and magnification? About 40% more, according to some conservative studies. How faint a star can your binocular detect? This will depend to some extent on the overall light transmission of your instrument, the aperture and magnification of your binocular, your local sky conditions and the individual’s visual acuity. First a word about how stellar brightness is measured. The stellar magnitude scale is a logarithmic scale that astronomers use to measure the brightness of stars. The scale was developed by the ancient Greek astronomer Hipparchus, who classified stars into six categories based on their brightness, with the brightest stars being classified as first magnitude and the faintest as sixth magnitude. In modern times, the scale has been extended to include even brighter stars (negative magnitudes) and fainter stars (higher magnitudes). The brightness of a star is measured by its apparent magnitude, which is how bright the star appears to an observer on Earth. The apparent magnitude of a star is affected by its distance from Earth, as well as any intervening dust or gas that may dim its light. The human eye can detect stars down to about sixth magnitude under ideal viewing conditions, such as a clear and dark night sky far from city lights. However, this varies greatly depending on a number of factors such as the individual’s eyesight, age, and level of light pollution including the presence or absence of the Moon) in the area. In general, most people will be able to see stars down to around magnitude 4 or 5 in moderately dark skies. But from the darkest places on Earth, even fainter stars can be detected. To observe fainter stars, astronomers use telescopes and binoculars that can gather more light and magnify the image of the star. These instruments can detect stars down to much fainter magnitudes, allowing astronomers to study objects that would be invisible to the naked eye. From a dark rural site, away from the bright lights of towns and cities, the table below gives some indication as to how deep you can go. Instrument 8×25 8×32 8×42 7×50 10×50 12×50 15×70 20×80

Faintest stars visible 8,8 9.1 9.5 9.5 10.0 10.2 11.0 11.4

The more popular models of binoculars for stargazing offer 8×, 10× and 12× magnifications, but larger models can go as high as 20× and 25×. It’s important to remember that higher magnifications don’t always mean better views. As brightness drops off with higher magnification, you should consider the size of the objective lens (the one you point at the sky). Larger objective lenses allow the binoculars to

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collect more light than the naked eye can, delivering the bright, sharp views you want from your nights standing out under the stars. For optical quality, I’d recommend multi-coated optics and BaK-4 prisms as a minimum. Size and weight can increase quickly as magnification and objective lens size change. These features mean quality optics combined with a good-sized objective lens. In truth any binocular is better than nothing for stargazing. This author enjoys using a small, hand-held 8×30 or 8×32 binocular for a lot of his stargazing forays. But if you’re new to the night sky, to get really hooked, you’ll need decent aperture to pull in enough light to keep you engaged. A really decent instrument that’s neither too big or too small is the ubiquitous 7×50, discussed at length in Chap. 6 on low light binoculars. Another great choice is the 8× or 10×42 roof prism binocular. It doesn’t have to have world class optics to satisfy either; just so long as it has a wide and well corrected field of view with multicoated optics. Here, I’ll discuss a few more economically priced 8× and 10×42 models worth considering if money is tight. We’ll also take a look at some state-of-the-art instruments used for astronomical viewing.

Opera Glasses on Steroids

Two super-wide angle Galilean binoculars: The Helios Starfield WA 2×40 (top) is smaller and considerably lighter than the Svbony SV 407 2.1×42 (bottom)

There’s nothing new under the Sun, and then some. Opera glasses have enjoyed a long history owing to their ability to generate low power, wide-angle views,

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enabling the theatregoer to get an ultra-stable view of the stage. In the past few years though, the opera glass has been modified to create a new type of observing experience under the starry heaven – enter the super-wide angle constellation binocular, employing powers not much more than 2× and offering up exceptionally large fields of view up to 36 degrees or so. Several models offering this kind of experience have been launched by companies such as Vixen, Orion USA and Svbony. But recently the well-known company Helios, now owned by Optical Vision Limited, has also produced their own rendition of this binocular to sate the demand of this niche observing experience; enter the Star Field 2×40 WA Galilean binocular. Having owned and tested out the Svbony SV 407 2.1×42, I was curious to learn about the Helios model, owing to its significantly smaller size and lighter weight, which would lend itself to longer hand-held views. Before getting into the details of this model, let’s look at the optical concept behind all these devices. First off, these are not true opera glasses – the eyepieces have additional lens elements to reduce aberrations inherent to the Galilean telescope design and greatly widen their field of view. The next thing to remember is that the human eye cannot harness the full light gathering power of these binoculars. On paper the exit pupil of the Helios Star Field 2×40 is 20 mm. The human eye pupil however has a maximum aperture of 7 mm, and as we age the aperture of the exit pupil decreases somewhat. So, let’s just say we have a 6 mm exit pupil (which is probably realistic for a middle-aged individual like me). Thus, the effective aperture will be 2×6  =  12  mm. So, effectively we’re dealing with a 12  mm aperture binocular offering a 2× magnification. So, what’s the deal with the 40 mm aperture of the objectives? Well, it turns out that with the Galilean optical design, the field of view it delivers is dictated by the size of the objectives – the larger their size, the greater the effective field of view. The reader will note that this principle does not apply to conventional binoculars. The 2× magnification will darken the sky by a factor of 2^2 or 4 times, and it’s the combination of the effective 12 mm aperture and the fourfold darkening of the sky that limits the faintness of stars visible through the instrument. In practice this results in a boost of about 1.5 magnitudes  – a useful gain in sensitivity over the naked eye view. Owing to the nature of the design of this super-low power modified Galilean binocular, there is no well-defined field stop and since the exit pupil of these designs is virtual, that is, it’s positioned inside the optical train, there’s no fixed locus to image the field of view. What this means in practice is that the closer one can get to the ocular field lenses the wider the field of view experienced. Unfortunately, eye glass wearers will not, in general, be able access the same size fields as non-eye glass wearers, so these are ideally suited to the latter group of individuals. Finally, despite their advertised field sizes, off-axis aberrations significantly curtail the size of the field that offers up well corrected stellar images. And this is where the quality of the optics gets factored in. Poorer quality instruments will manifest off-axis aberrations closer to the center than better made brands. Now let’s take a closer look at the Helios Star Field WA 2×40 The first thing I noted about the Helios Star Field is its light weight. At only 189 g, it’s nearly half the weight of the Svbony SV 407 2.1×42. And it’s considerably smaller too. The

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optics are fully multicoated on all lens surfaces. I was unable to detect any internal reflections when pointing the instrument at a bright artificial light source. The eyepieces must be adjusted individually by turning them clockwise or anti-clockwise. The diopter compensation range is from −5 to+3. Turning the oculars is smooth and completely backlash free. The chassis is made from high quality machined aluminum. And while lightweight, it has the feeling of quality when you hold it in one’s hands. Indeed, the Svbony model, in comparison, is just plain over-built. There’s absolutely no need for a device like this to weigh so much! The eyepieces have 10 mm of eye relief; that’s not bad considering other models only have 8.5 mm or so. That said, one of the things that niggles me about all these devices is that the lenses can get smudged from eyelashes rubbing against the surface, necessitating more frequent cleaning. This is not directed at the Helios Star field 2×40 alone. All the other models have the same issue. There’s no provision to mate the Star Field to a tripod, but such a lightweight device doesn’t need one. Indeed, I think it even defeats the purpose of these devices which were surely created to enjoy freely in the hand. The instrument comes complete with a quality neck strap, but I elected not to use it as it is so lightweight and small enough to put in a medium sized pocket. I love the carry case that accompanies the instrument; its sturdy hard shell will protect your investment from knocks and bumps while not in use. It zips closed to keep out dust and moisture and has a neat little carry strap attached for transport. All in all, the Helios Star Field is very nicely engineered product that feels good in the hand; top marks for ergonomics!

The carry case is small and elegant. It zips closed to protect the instrument from the elements and can fit inside a jacket pocket

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To be honest, I was quite underwhelmed by the performance of the Svbony SV 407 2.1×42. It had too many off axis aberrations in both daylight and night-time tests. These observations colored my opinion of these devices so much that I was under the impression that they were all pretty much the same. Thankfully, nothing could’ve been further from the truth! Comparing the Helios Star Field 2×40 and Svbony 2.1×42 in A/B tests confirmed that the Helios was in a completely different league to the Svbony. The Helios was slightly sharper on axis, with better contrast, and had a much larger sweet spot than the Svbony. I would estimate that the effects of field curvature were not at all intrusive in the central 50% of the field of the Helios Star Field but was more like ~30% in the case of the Svbony. These differences were striking and completely unexpected! After adjusting the eyepieces to accommodate my eyes and setting them at infinity focus, I was immediately taken by the huge contrast boost, as well as the resolution gain over the naked eye. The image revealed colors far more vividly and I was able to see much finer details on high-contrast objects like the grain of wooden fences in the middle distance. Field depth is extraordinary in the Helios Star Field 2×40. I estimated close focus at infinity to be about 4.5–5 m! After a few minutes glassing with this instrument, the view becomes so immersive and thought-­ provoking you can easily forget that the view is magnified. I was especially thrilled when I brought the instrument for a stroll through my local woods, where I could view vast swathes of forest with excellent clarity and depth perception. It was like having bionic eyes! Adjusting the eyepieces, I was able to obtain tack-sharp images of Red Campion beds as close as 1.9  m away, so a little better than advertised. Indeed, when they come within about 10–15 meters from you, the Helios Star Field 2×40 served up excellent details of Blackbirds, Chaffinches and Song Thrushes foraging in the leaf litter on the forest floor. I was even lucky enough to watch the climbing antics of a little Tree Creeper inching its way up the trunk of a majestic Scots Pine some 12 meters in the distance. Because of its ultra-low magnification, these devices are well suited to observing landscapes in moving vehicles. Sitting in the passenger seat of my car, I enjoyed views of hills, mountains and watercourses, while passing through scenic terrain. Another daytime activity one can engage in with this instrument is cloud watching. What’s better than a cloudless summer day? A day with sunshine and white, fluffy clouds! The Helios Star Field 2×40 is an excellent tool for watching clouds morph in real time as they race across the sky. The obvious gain in contrast and resolution can transform a rather ordinary looking cloud mass into a veritable labyrinth of form and structure. I enjoyed a few passing minutes in the late evening sitting back in my zero-gravity chair watching clouds catch the last light of a setting Sun. And even after dark, it’s wonderful to watch clouds passing by or near a bright Moon, creating wondrous spectacles of light and color. And at my high northerly latitude, I’ve used it to study marvelous noctilucent clouds during the height of our Scottish summer. Twilight can also be a wonderful time to admire beautiful silhouettes of trees, their branches showing up much more vividly compared with the naked eye. Horizons become fascinating targets with this low power glass too, with old and

Night Sky Testing

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abandoned farmhouses, hilltops, farm silos and even windmills making fascinating targets for study as the Sun races towards the netherworld. The instrument showed up no annoying internal reflections when turned toward a bright artificial light source at night, or on a bright full Moon, so this will be a good glass to enjoy panoramic views of cityscapes and harbor lights at night. I can also see a use for these glasses for short-range birding in the garden. If you have a bird table or feeder near your windows, the excellent natural, immersive views of the Helios Starfield 2×40 will serve as a great tool for those who want to get just a little closer to the action.

Night Sky Testing My first test of the Helios Starfield 2×40 under the stars in my rural Scottish backyard setting came when I compared it briefly to the Svbony model described earlier. Turning the instruments towards the main stars of Cygnus lying nearly overhead, I could immediately see a significant difference between them. Specifically, when I centered Sadr (Gamma Cygni) in the field, I noticed that Epsilon Cygni was clean and sharply focused in the Helios Star Field but conspicuously blurred in the SV 407 2.1×42. This confirmed what I had noticed during daylight testing. It was at this point that I put the Svbony away in its case and concentrated on the Helios. I consider the latter to be not good value for money, as it retails for about £20 more on Amazon compared with the Helios glass. I was immediately struck with the sheer clarity with which I could make out the entirety of Cygnus, most of Lyra and even Vulpecula. Stars quite invisible to the naked eye popped into view while glassing with the Helios and I can confirm that a solid magnitude gain of about 1.5 magnitudes was indeed realistic. I also enjoyed the view of Delphinus with its distinctive diamond asterism, as well as exploring the glories of Aquilla sat next door to it, as it were, to the west. I could immediately see how this little super-low power glass will serve as a great tool for teaching youngsters about the constellations, even from a light polluted town or city. In yet another test, I centered the Big Dipper in the Helios Star Field 2×40 and was delighted to see that it was quite well delineated throughout. Furthermore, several ‘new’ 6–7th magnitude stars popped into view in the bowl asterism confirming its modest increase in light grasp over the naked eye view. The Andromeda Galaxy (M31) was easy to make out above and to the east of the Square of Pegasus but when I scanned the region of the sky in Triangulum, try as I may, I could not make out even a trace of the famous Pinwheel Galaxy (M33), but my luck was to change when I brought the Helios Starfield 2×40 along with me on vacation to Pembroke shire, south Wales. Here, miles away from big towns and cities, the sky is gloriously dark and transparent, and even though the Moon was in the sky, it skirted the horizon for the most part, setting early enough for me to enjoy the night sky without its ‘light pollution’. Here, I was easily able to make out a faint smudge of light marking the spot of M33, but I also enjoyed many short spells, lying flat on my back on a sun recliner,

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in absolute awe of the view served up by this low power super-wide-angle binocular. The Milky Way running through Cygnus was stunning, where I could make out shoals of stars interspersed by dark, cavernous regions completely devoid of star light. In my mind’s eye, I remembered the star gazing adventures of the young Edward Emerson Barnard (whose life is celebrated in my historical work, Chronicling the Golden Age of Astronomy), as he lay down on the back of a wagon at night, mesmerized by the blazing heavens above his head. Looking east towards Perseus I was delighted to scoop up several bright shooting stars emanating from the radiant of the Perseid meteor shower culminating on the night of August 12. And while it was still quite low in the eastern sky at or around local midnight from this vantage, I came to appreciate just how useful this instrument will be for observing other meteor showers active throughout the astronomical year. The ‘Wonky W’ of Cassiopeia was beautifully framed in the Helios Star Field and below it, the famous Double Cluster was very easy to pick off. An instrument like this is brilliant for highlighting the smaller, fainter or more obscure constellations like Lacerta, Sagitta and Cepheus. I was also struck by how easily I could make out the colors of fainter naked eye stars. For example, Mu Cephei- Herschel’s Garnet Star – stood out as distinctly but faintly red, whereas, using the naked eye its colour is quite beyond me. Though there were no bright comets in the sky during my testing, I can easily see how a glass like this would be awesome for observing the tail of a bright, icy interloper from the Kuiper Belt or Oort Cloud. Here’s hoping I get a chance to put this idea to the test! It is undoubtedly the case that an instrument such as the Helios Starfield 2×40 works best under dark, pristine skies, but I can also see many uses for it in light polluted places, where its ability to darken the sky significantly will help urban or suburban amateurs to find their way round the sky more easily. I can’t think of a better binocular for youngsters to learn the constellations with. They stand out very clearly, as if you’re looking at a star map. And for daytime use, they give a good boost in both contrast and resolution without overwhelming the senses. One thing you need to watch for with smaller people is the IPD range, which is 56–72 mm with the Helios Starfield 2×40. There is a little bit more wiggle room in lower light conditions owing to a child’s larger exit pupil which makes it slightly easier to center the eyes and merge both images. In summary, I really enjoyed the views through the Helios Starfield 2×40 and would heartily recommend it to anyone. For a very modest investment of £99.00, you’ll get a nicely engineered super-wide-angle binocular that delivers excellent enhancements over the naked eye. I can’t wait to explore the glories of Taurus and Orion later in the season with this quirky little naked eye ‘extender,’ when it will help to lift the spirits above the cold and the dark of long winter nights. One more thing, there are reports that even better models are available at significantly higher retail prices. The Orion 2×54 Ultra-Wide-Angle binoculars serve up a whopping 36 degrees of true field, considerably larger than the Helios Starfield, and can be had for $159.99. Now back to more traditional stargazing instruments.

A Surprisingly Good Compact Astronomical Binocular from Nikon: The Nikon E II…

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 Surprisingly Good Compact Astronomical Binocular A from Nikon: The Nikon E II 10×35

The Nikon E II 10×35

I have cultivated a strong preference for smaller exit pupils (4 mm or less) when viewing the starry heavens, preferring 10×42 over 8×42, for example. The smaller exit pupil ensures that you’re imaging the field with the best (least curved) part of your eye. Larger exit pupils bring out the astigmatism in my eyes, distorting the images of point sources like stars. In addition, smaller exit pupils create more contrast between the stars and the background sky, painting more aesthetically pleasing vistas. Observing in summer twilight, when the sky doesn’t get properly dark, comparing the views through an 8×42 and a 10×35 shows the advantages of the smaller exit pupil. The 10×35 darkens the background sky much more effectively than the 8×42, causing the stars to stand out more. I have thoroughly enjoyed the astronomical views through the Nikon E 10×35 with its generous 6.6-degree field, discussed at length in my Chap. 30 on classic binoculars, but I must say the more advanced EII 10×35 is a nice step up, with its magnificent 7+degree true field. Stars remain tight pinpoints within a generously large sweet spot, with only mild field curvature and astigmatism creeping up as one approaches the field stop. The Nikon E II 10×35 exudes ergonomic and optical quality. It has a beautiful diecast magnesium alloy chassis, a silky-smooth focus wheel and very high light transmission. It’s also feather light at just over 600 g. Another nice feature of the E II 10×35 is that there is a negligible drop in field illumination at the field edges, making the field appear larger than it really is. Although it doesn’t have the reach of

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a more traditional 10×50, its low weight and excellent form factor render it decidedly ‘handier’ than the larger 10×50 glass. For serious astronomical forays, 10×50 is the better option, but for casual stargazing, especially doing autumn Milky Way sweeps, the 10×35 simply can’t be beat. This is a world class binocular with a price tag to match. Expect to pay $800 for the privilege of owning one.

 Classic Porro Prism Binocular from Nikon: The Aculon A A211 10×50

The Nikon Aculon A211 10×50

The Japanese Camera Giant Nikon manufacture an interesting series of economically priced Porro prism binoculars. Known as the Aculon A211 series, it consists of seven models to choose from in 35 mm, 42 mm and 50 mm aperture classes. All the Aculon binoculars are made in Nikon’s China plant. I tested out the 10×50 model. Weighing 900  g without the neck strap, the Aculon is covered in a thick armoring of rubber with excellent grip. I do like the gold lettering on the barrels, which helps give these instruments a touch of class. The central focus wheel is large, easy to access, and turns smoothly through 1.25 turns clockwise from closest focus to just beyond infinity. Close focus is about 7 meters. The eyecups on all the Aculon models are of the twist-up variety with two intermediate positions. Eye relief is very tight though – just 11.8 mm – so this will be a very difficult binocular to enjoy using eyeglasses. Nikon say that all of the optical components are multi-layer coated, but that’s strictly not the same as being fully multicoated. I also liked the nicely recessed

A Classic Porro Prism Binocular from Nikon: The Aculon A211 10×50

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objective lenses on the Aculon – a bonus since this will partly protect them from rain, dust and peripheral light. None of the Aculon models are waterproof though and their lack of nitrogen purging internally means that they are likely to fog up if taken from the cold night air to a warm room indoors. Thus, appropriate care must be taken to ensure that they perform adequately in adverse weather conditions. The Nikon Aculon A211 10×50 feels good in the hand and delivers a very decent 6.5 degree field, although I did pick up a few moderately bright internal reflections after pointing the instrument at a bright street lamp. When I compared it to another 10×50 Porro prism binocular, which has fully multi-coated optics, I could immediately see that it had very little, if any significant internal reflections on the same streetlamp in comparison. Daytime views are quite good in bright daylight conditions, with good contrast and very good center sharpness. Edge of field performance is passable too, thanks to the built-in aspherical lens elements in the eyepieces. Chromatic aberration is well controlled with only a trace seen around high contrast objects. Glare suppression is good but not the best I’ve seen in other 10×50 Porro prism binoculars. Indeed, I was able to see a small amount of veiling glare  – a washed out arc of contrast-robbing light caused by the reflection off the bottom edges of the objective lenses which was present no matter where I pointed the binocular. The Moon looks great in the Nikon Aculon A211 10×50, with crisp images of the crater fields, lunar seas and mountain ranges. Very little chromatic aberration could be seen on axis, but it was easy to pick some lateral color when the Moon was placed near the field stops. Views of Milky Way star fields are very impressive in this 10×50 too. I enjoyed searching out numerous open clusters with this nifty light cup, including M35 in Gemini, and M44 in Cancer. Views of the Orion Belt stars and Nebula were also impressive on a dark, moonless December evening. I also enjoyed some showpiece binocular double stars, such as Mizar and Alcor, O1 and O2 Cygni and when tripod mounted, I was able to resolve that beautiful color contrast double Albireo (Beta Cygni). I also had the opportunity to test its higher power sibling, the Nikon Aculon 16×50, which is super light at 940  g. This higher-power Aculon had quite a few internal reflections when I turned it on a streetlamp after dark. Daytime views were OK in bright sunlight but got noticeably dimmer when glassing in heavily overcast daylight conditions. Chromatic aberration was also much easier to see on many high contrast targets, but I judged the overall performance to be satisfactory, given its modest price tag. Surely 16× will reel in more numerous fainter stars than the 10× instrument I hear you say. Well, that’s not exactly how it turned out as a matter of fact. Let’s do the number crunching. Although they have the same aperture of 50 mm, the same light is spread over a surface area 2.56 times larger than the 10× Aculon, which helps darken the sky more. But the exit pupil of the 16×50 model is only 3.1 mm as opposed to 5 mm for the 10×50 Nikon Aculon, reducing the pupil’s surface area by the same factor  – 2.56. Thus, a darkened sky with an equally restricted exit pupil will greatly reduce one’s ability to image faint extended objects such as galaxies – something I was able to verify easily with some observations on some of the brighter Messier galaxies in Leo. The 10×50 was far better at sweeping

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these objects up than the 16×50. I did find that the latter was better at seeing fine detail on the Moon though, as one expects from its higher magnification. So what is the 16×50 good for? I would say it comes in handy for spotting objects in the distance, for daylight surveillance and maybe quick looks at the night sky. The 10×50 model is far more versatile though, making a rather good low light binocular by day and a much more capable astronomy binocular by night. Having sampled these two instruments from Nikon, I came away with the Aculons were a decent series of cost-­ effective binoculars when they first came out, but they’ve had their day in the Sun. More contemporary models in the same price range have more advanced coatings, resulting in better contrast and more aggressive glare suppression.

The Trailseeker 8×42 The Trailseeker 8×42 from Celestron is a good choice for casual stargazing. With a strong but lightweight magnesium alloy chassis overlaid with a thick layer of black rubber armoring weighing about 650 g. They’re great if you’ll be moving between temperatures (e.g., from inside with the central heating on to the great outdoors on a frosty night) thanks to the nitrogen purging and a waterproof design which means they won’t fog up. Another nice feature of the Celestron TrailSeeker 8×42 is its minimal false color which often forms a purple or blue hue around brighter targets. I detected very little in the field of view, particularly along the lunar limb. That’s down to the hi-tech goodies built into everyone of these binoculars; fully broadband multi-coated lenses, phase and dielectrically coated BaK4 roof prisms. And when you get tired of hand-holding the instrument, the Trailseeker has a built-in socket to allow it to be mated to a tripod or monopod for steady viewing. The field of view is very generous at 8.1 angular degrees. Stars remain sharp and pinpoint-like across the inner 70% of the field, after which some distortion and field curvature begin to become more noticeable, but in general it’s not a problem with this model.

A Sprightly 10×42 from Vortex

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The Celestron Tralseeker 8×42

I was able to enjoy some great views of the Milky Way with the Trailseeker 8×42 when I took it on vacation to a dark sky site at a coastal location in southwest Wales. Showpiece objects of the sky such as the Andromeda Galaxy (M31), the Coathanger asterism in Vulpecula, numerous colorful binocular doubles. And while these binoculars don’t have ED glass, the colors served up of bright stars are color pure without any fringing on-axis. These are very decent binoculars that can be used by day and by night and though they can be hand-held for extended sky watching, you can easily affix them to a tripod or monopod for ultra-stable astronomical viewing. These versatile binoculars retail for about $300.

A Sprightly 10×42 from Vortex Much as 8×42 models offer nice wide fields, I personally prefer 10×42 for stargazing. That extra magnification gains you about a quarter of a visual magnitude of fainter stars, despite the smaller exit pupil. In addition, I’ve often noticed that the star images in the smaller exit pupil of the 10×42 are a little tidier to my eye, a consequence I suppose of the smaller exit pupil cutting off the outer part of the eye lens where aberrations are more easily discerned.

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Vortex Diamondback HD 10×42 is one of the lightest binoculars in its size class

Vortex, a US-based company founded in 2002  in Middleton, Wisconsin, has grown to become one of the leading manufacturers of good but economically priced binoculars for the growing sports optics industry. Today they sell an impressive range of binoculars, monoculars, spotting scopes, rangefinders, riflescopes and other products, mainly for the American market, but have also made very solid inroads here in Europe. Arguably their best-selling product is their highly popular Diamondback binocular range, which first came to market in the early noughties, but has undergone a number of upgrades over the years. The second-generation Diamondbacks came out in 2016, and mainly involved improvements in the ergonomics of the chassis. Then in 2019, a third generation of the Diamondback series was introduced. This time, no changes were made to the ergonomic features of the binocular, but the optics received an upgrade to so-called HD status, which promised better color correction, contrast and edge of field performance. The Diamondback HD series offers an extensive range of binoculars in apertures all the way from 28 mm right up to 56 mm. This review will concentrate on the 10×42 HD, particularly popular with birders and hunters. The package arrived in a single box, housing the binoculars, the Glasspak case and strap, lens cleaning cloth, padded logoed neck strap, an instruction card and VIP warranty information. The binocular was presented with its rain guard and tethered objective covers attached. Examining the instrument, I was quite impressed with its streamlined appearance and robust build quality. The magnesium composite chassis is overlaid by a tough green rubber armoring, textured on the sides for extra grip. The twist-up eye cups worked perfectly from the get-go, and the central focusing

A Sprightly 10×42 from Vortex

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wheel rotated smoothly without any free play. The central hinge was quite stiff out of the box and held my personal IPD very well over a few weeks of testing. The right eye diopter turned only with a fair amount of effort  – a good thing surely. Overall, the cosmetic appearance of the instrument was flawless. So far, so very good. From the moment I first held the Diamondback HD 10×42 in my hands, I got the distinct impression of quality. This is a well-designed and refined binocular, and it shows. Everything is mature and well thought through. The eye cups are made from a very tough rubber substrate, which have three positions to suit various eye placements, with and without glasses. They twist up with one intermediary position, and a loud click tells you they are rigidly in place. Nice engineering! I found no issues seeing the entire field of view without glasses and the eye cups fully extended outwards. I did however have a bit of an issue seeing the entire field when I retracted them using eyeglasses, but you could get there with a squeeze… but only just. In use, I sometimes got the impression that they were a tad too hard when pushed up against my eyes, but it wasn’t a big deal in field use. The focus wheel rotates very smoothly and accurately, with a nice amount of traction. It is neither too fast nor too slow. I suspect many users will find it just fine. From one end of focus travel to the other takes just 1.5 turns. The diopter ring, which is located under the right ocular, has an acceptable amount of tension so that one needn’t worry that it will slip out of position easily. A prominently visible, white line indicates your correct setting and small but distinctly visible dots on either side presumably indicate plus and minus settings, though it’s not clear which is which until you dial in your preferred setting. The underside of the binocular has two prominent thumb indents. While many users might find them useful, I found that my own thumbs didn’t naturally rest there to obtain the most stable handheld views. The objectives are not very deeply recessed as mid-sized binoculars come. I suspect this was a design compromise to shave off as much weight as possible from the binocular in order to maximize its portability. But in my experience, this only increases the chances of picking up glare in field use. More on this later. On the plus side though, the Diamondback HD 10×42 tips the scales at just over 600  g  – a remarkable fact! Indeed, it is much lighter than the vast majority of binoculars in this size class. The internal optics are argon purged and O-ring sealed. Why argon? Well, it’s an inexpensive noble gas, so is completely unreactive. Whether argon is better than nitrogen is debatable though, as according to an analysis by Holger Merlitz, the low ambient concentration of argon would set up a larger concentration gradient than with nitrogen, resulting in a faster net diffusion outward despite it having a larger atomic mass than nitrogen. My first look through the binocular on a dull overcast winter day proved very promising. The Diamondback HD 10×42 threw up a very good image, with a big sweet spot within which the image was very sharp. Contrast and color fidelity were also very good. I detected the merest trace of chromatic aberration in the center of the image which became progressively more prominent when the targets were moved off axis, but overall, I judged the color correction to be very good. Edge of field sharpness fell off a bit, starting from about 65% out from the center of the field.

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As an astronomer, I’ve learned that the best way to test binocular aberrations is not during daylight observations, but under the night sky. Rising before the Sun on a late January morning showed a last quarter Moon to be nice and sharp within the sweet spot, with very little colour fringing at the limbs. Moving the Moon off axis showed up more lateral colour and some drop off in illumination, as the bright, silvery orb was brought progressively closer to the edge. Right at the edge of the field, the lunar image became darker and a bit fuzzy. I was able to refocus it to some degree, but was unable to obtain a perfectly sharp image. The same was true when I turned the Diamondback HD 10×42 on some bright winter stars like Capella and Procyon. Stars remained crisp and tightly focused out to about 65% of the distance from the center, before significant distortions began to creep in. Stars placed at the edge of the field could be improved somewhat by re-focusing but not entirely so, indicating that field curvature was not the only geometrical aberration in evidence, with astigmatism being the most likely culprit. Collimation was shown to be quite excellent in the Diamondback HD however, as evidenced by seeing a perfectly focused star at the center of a defocused diffraction disk, evinced by rotating the right eye diopter ring to the extreme of its travel. The Diamondback HD 10×42 did throw up some glare though. While looking towards a setting Sun behind some thin clouds, the field became a bit washed out. Veiling glare was also in evidence as a bright arc of light at the bottom of the field when I pointed the binocular high up into the canopy of some conifer trees against a bright overcast sky. And while shielding the objectives with an outstretched hand removed a lot of this unwanted glare, it couldn’t remove all of it. I believe this could be significantly improved by recessing the objectives more deeply than they are. The Diamondback HD 10×42 is a very good star gazing binocular that serves up impressive images, with no serious optical defects. It does many things very well but falls short of being considered outstanding. It’s a pleasure to use in the field, with a tough, lightweight chassis, excellent twist-up eyecups, and a well-designed focus wheel. While it is unlikely to impress those used to looking through substantially more expensive models, it will certainly deliver the readies for most applications. And when you factor in its modest cost - $250 – and VIP warranty, I believe it offers a lot of bang for the buck, making it easy to see why it remains a very popular choice for stargazers across the world.

A High-Class ED Porro Prism Binocular from Oberwerk

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A High-Class ED Porro Prism Binocular from Oberwerk

The Oberwerk SE 10×42ED

If you’re a Porro fan and enjoy a decidedly modern twist on this tried and trusted binocular design, then I’d strongly recommend giving the Oberwerk SE 10×42 ED a test drive. This high-performance binocular is built like a proverbial tank, but the handling is superb. Tipping the scales at 872 g, it’s basically the big brother of the superb 8×32 ED model I show cased in a previous chapter. Like its smaller sibling, the 10×42 SE is fully broadband multi-coated, possesses high-index Bak4 prisms and FK61 ED glass to reduce color fringing to an absolute minimum. Based on the famous but now discontinued Nikon SE 10×42, Kevin Busarow, founder and CEO of Oberwerk based in Dayton Ohio, wanted to bring to market a thoroughly modernized interpretation of a well loved modern classic. Gone are the rubber eyecups. These have twist up eye cups with 4 detents and offer up enough useable eye relief (15 mm) to allow you to engage with the entire field while wearing eyeglasses. The large central focus wheel is covered with a durable rubber substrate with deep ridges for excellent gripping. 1.5 revolutions anticlockwise takes from closest focus to infinity. Movement is a very smooth and precise and slightly on the slow side, making it especially suited to hunting. Unlike the original Nikon SEs, these Oberwerk wonder Porros are nitrogen purged and waterproof, so you can use them in any weather conditions. I tested these claims by exposing the binocular to subzero night temperatures before bringing it back into a warm living room. As expected, the outer lenses fogged up, but as soon as the condensation dispersed, I could see no internal fogging whatsoever! Good job Oberwerk. Subsequent research

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on this company revealed that Oberwerk were delivering waterproof and fog proof Porros for nearly two decades as evidenced by a reference to this fact in Phil Harrngton’s 2007 edition of Star Ware. Performance-wise the Oberwerk SE 10×42 ED delivers a powerful optical wallop, with its wide and well corrected field of view (6.5 degrees, but measured at 6.44 degrees), excellent central sharpness and well above average edge of field performance. The smaller 8×32 model displayed superb color correction thanks to the addition of an ED glass (FK-61) element in the objective. I’m happy to report that the 10×42 also has excellent color correction too, though not quite to the same degree as the 8×32. This is entirely to be expected as chromatic aberration becomes more obvious at higher magnifications and the extra light gathered by the larger 42 mm objectives. That said, in various tests conducted outside in good overcast lighting conditions, I did detect a trace on the highest contrast targets and only near the field stops. Close focus on my test unit was 4.39 meters, not ideal for close up work watching butterflies for sure, but a glass like this was really designed for long-­ range viewing, a task it fulfils perfectly. As a dedicated Porro prism binocular fan, I particularly enjoyed the greater stereopsis effects garnered by this 10× glass. Indeed, as I explained in Chap. 1, seeing 3D effects is amplified by magnification as it resolves those spatial differences between objects better. One afternoon, I was glassing at my local freshwater pond, I aimed at some fallen tree trunks at the south shore of the pond in the middle distance and was simply bowled over by the contouring of the wood – its bumps and depressions being clearly in evidence. On another afternoon, I returned with an 8×25 roof prism pocket binocular together with the Oberwerk SE 10×42 ED and compared the images of the fallen tree trunks from the same vantage. The differences were clear and unambiguous: the Oberwerk delivered a much more dramatic 3D effect than the little roof prism binocular, a consequence of its greater magnification and the larger separation of the objective lenses. The larger aperture and increased magnification of the Oberwerk SE 10×42 ED makes it an excellent choice for stargazing, where it goes considerably deeper than any 32 mm instrument. I enjoyed some magnificent views of some of early spring sky’s show pieces including the Beehive Cluster in Cancer, the sprawling Coma Berenices Cluster, the galactic duo, M81 & M82 in Ursa Major, the globular clusters M13 and M92 in Hercules and a raft of Messier galaxies in Leo, Stars are rendered in their natural colors with no visible chromatic aberration apparent. Its good edge of field correction keeps stars from morphing into unpleasant blobs or streaks. For maximum stabilization I’d recommend placing this instrument on a monopod. Indeed, on the evening of April 10, I was using this binocular on a monopod and turned it on the bright planet Venus, now sinking into the western sky. I was amazed and delighted to pick up the Pleiades star cluster in the same field of view. Although I first spied it at around 9:15  pm local time, the sky was not yet fully dark, so I decided to have another look after 10 pm. I wasn’t disappointed: the view was quite simply stunning. Venus shone with an intensely bright white hue and the fainter stars in the Pleiades were now in plain sight. It’s for apparitions like these that the Oberwerk really excels!

A Re-designed 10×50 Classic Porro from Pentax

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Oberwerk have delivered yet another excellent product to market at a very reasonable price ($279.95). Optically, I rate it very highly indeed. It’s fully equivalent to an upper tier roof prism binocular which costs double or triple its model retail price. While I’m on the subject, readers may be interested in the larger Oberwerk 12×50 SE model for higher magnification amateur astronomy and more long-range terrestrial viewing. Whichever model you choose, you’ll surely be very impressed!

A Re-designed 10×50 Classic Porro from Pentax

The Pentax SP 10×50 WP

Pentax is a company long synonymous with good optical quality. Over the last several years, I’ve reviewed a few models manufactured by this company, ranging from the very small l (6.5×21) to the very large (20×60). In particular, I’ve included an earlier incarnation of the 20×60 SP model in my own personal arsenal of binoculars (discussed later in the chapter), where it’s employed in deep sky observation and regular white light solar observing. So, I was excited to see how its smaller sibling, the 10×50 SP WP, would shape up in field tests. The binocular arrived double boxed, including the instrument itself, packed inside its soft case, together with plastic end caps for both the ocular and objective lenses, a logoed padded next strap and instruction sheet with the warranty. The plastic caps that protect the optics of the 10×50 SP looked identical to those that accompanied my 20×60, and together with the woefully inadequate soft case, represent the

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weakest links in the entire package. The caps are loosely fitting and invariably fall off when the binocular is picked up. As for the case, it does very little to protect the binocular from serious knocks so should really be upgraded to either a padded soft case or better still, an aluminum hard case to protect your investment. Thankfully, my initial impressions of the binocular itself were far more favorable. When I unpacked it, I was immediately struck by its rugged build quality. The binocular is a hefty 1 kg weight and is covered with a thick layer of synthetic rubber identical to that found on my 20×60. Like its bigger brother, it has a lockable focuser; simply push the wheel forward and it disengages with the internal gearing, preventing the wheel from being moved. Although not an essential feature by any means, I can see where it would come in useful if one observes targets at a fixed distance from the user or when observing the night sky, where all the subjects are located more or less at infinity. The twist up eyecups are very well made and very comfortable to use. There are three positions; fully down, intermediate and fully extended. Eye relief is a very generous 20 mm. Usually, I observe with the eye cups fully extended but I actually found the view to be most comfortable and immersive at the intermediate position without wearing eye glasses. The ‘WP’ part of its name, I assume, refers to ‘Water Proof,’ with a specified JIS class 6 rating. The instrument is purged with dry nitrogen gas to prevent internal fogging and is o-ring sealed. These newer SP models also feature hydrophobic coatings applied to the outer lenses to help repel water and oily fingerprints at bay. The diopter compensation ring is located under the right ocular lens and is negotiated by moving an easy to access lever which can be adjusted clockwise or anti-clockwise. It is reasonably stiff to the touch so should hold its position well. The underside of the 10×50 SP WP has two large thumb indents for easier hand holding. I found that my thumbs naturally rested in them while holding the binocular up to my eyes. The focus wheel is very stiff; a strict no-no for birding or any activity that requires rapid focus changes. But for stargazing or for stationary targets located in the distance, it works just fine. The proof of the pudding, of course, lies in the eating, and this is where this well-made classic Porro prism binocular really shines. The SP series underwent an upgrade from the first-generation models, with better multi-­ layer anti-reflection coatings being applied throughout the optical train. Allbinos tested this model out and measured a light transmission value of about 85%, which is very good indeed considering the modest price tag on this binocular, as well as the fact that some of the world’s best Porro prism binos achieve about 95% or so. Inspecting the innards of the instrument in broad daylight showed it to be clean and dust free. Setting up my iphone torch to its highest setting in my back garden at dusk and placing it a comfortable distance away revealed a few minor internal reflections and no diffraction spikes or diffused areas; another good result indicating that all was well with the instrument in keeping bright light sources under control. Placing the beam just outside the field of view showed very little ghosting so this will be a good binocular to observe bright objects in the night sky such as the full Moon and stars located near it. It will also garner excellent views of cityscapes at night. Close focus was measured to be about 5.3 meters  – a little better than

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advertised but nothing to write home about. The coatings on the ocular and objective lenses seem to be very evenly applied. In addition, the objective lenses are very deeply recessed which helps protect the optics from the vagaries of the British climate and also cuts down on stray light. In broad daylight, the view through the Pentax 10×50 SP WP is very impressive, with great contrast, good color rendition and good but not outstanding control of glare. Depth of focus is not bad, but the 3D pop that Porro prism binoculars are famous for was there in spades. Color correction is excellent, even off axis, where one can detect a small amount of lateral color. Field curvature is very gentle but does show a fairly minimal amount of pincushion distortion near the field stops. Even though the field of view is fairly narrow at 5 angular degrees, it didn’t feel overly restrictive to my eyes. At just over 1 kg weight and delivering a 10× optical boost, these are not binoculars that one could handhold for long but it’s certainly possible to scan the landscape and night sky for a few minutes before some fatigue sets in. These are however, perfect for use on a lightweight monopod or tripod for ultra-stable viewing. Further testing at dusk showed excellent control of internal reflections and clean, crisp images garnered from a bright sodium streetlamp. Placing the lamp just outside the field of view showed no significant off-axis flares. Placing the binocular on a light weight monopod and turning them on the night sky also served up excellent results. Centering the bright summer luminary, Vega, in the binocular field and focusing in showed a pinpoint sharp image with no secondary spectrum and with no diffraction spikes. Better still, moving the star to the edge of the field induced only a little distortion and some lateral color (purple fringing), indicating that the aspherical optical element built into the eyepieces of the Pentax SP binocular were doing their jobs well. And while the skies were far too bright to provide a more in-depth study, with strong Summer twilight upon us here in central Scotland, I compared and contrasted the view through the Pentax 10×50 and my trusty Barr & Stroud Series 5 8×42 mounted on a second monopod. Turning my attention to the well placed Coathanger asterism in Vulpecula revealed a cleanly resolved view in both instruments, but with fainter stars showing up better in the Pentax, albeit in a smaller true field. In recent years, thanks to great advances in technology, there has been a steady movement within the amateur community towards roof prism designs over older, Porro prism binoculars. But after spending a few weeks testing out this affordable model from Pentax, I was genuinely surprised and delighted by its optical performance. Indeed, you’d have to fork much more money for a roof prism binocular with the same specifications as this Pentax to get the same optical quality. The only real advantage of the roof prism incarnations at 10×50 are their lower mass (but not by much) and slightly smaller frames. Having sampled a few inexpensive and mid-­ priced 10×50 roof prism binoculars in the past, I can say hand on heart, that they infrequently deliver the light transmission values anywhere near those attained by this classic, affordable 10×50. Indeed, I would strongly recommend readers to look more closely at tried and trusted Porro prism designs in aperture classes of 50 mm or above over the roof prism varieties, especially now that they come with full

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waterproofing. Who would I recommend this instrument to? Amateur astronomers looking for quality deep sky views on dark, clear nights, and casual daytime viewers with permanently set-up tripods or monopods surveying targets set in the distance. Remember that five degrees is still plenty good enough for the vast majority of deep sky observing! These would work very well in holiday cottages set by a lake or overlooking a picturesque valley floor. And although they can be handheld for short excursions, they do benefit greatly from mounting. The Pentax SP 10×50 WP retails for about £189 in the UK.

A Robust 10×50 from Bresser

The Bresser Wave 10×50

Bresser is no stranger to the field of sports optics and astronomy. Recently the company launched their Wave series of grey rubber armored 42 mm and 50 mm roof prism models at very reasonable prices. The 10×50 Bresser wave caught my eye as a potentially good stargazing binocular. Let’s look at its specs; 758 g, fully multicoated optics, twist up eye cups offering 18.2 mm eye relief, waterproof and fog proof construction, a large and wide focus wheel under 2.25 turns to go from one extreme of focus to the other. There’s no mention of the prisms being phase coated though, at least according to the official specs. Users report a really great image, especially in the center of the field, with some peripheral softness near the field edges. The field of view of the Bresser Wave – 5.4 degrees – is a little restrictive compared to other 10×50 models though. Images of the Moon are razor sharp in the Bresser with great details coming through from the crater fields, mountain ranges and lunar seas. Stars are crisp and sharp, only showing some lateral color near the field stop. Open clusters like the Pleaides, the Double Cluster in Perseus and a suite

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of bright Messier objects look great in this binocular, although you’ll need to mount it on a monopod or tripod to get the steadiest views.

Stargazing Porros from Opticron The UK-based company Opticron are to be lauded for bringing to market a number of economically priced 10×50 Porro prism binoculars to explore the night sky. If you liked the Adventurer T WP 10×50 discussed in Chap. 6, Opticron offer an even better featured model which is fully waterproof and filled with dry nitrogen gas; enter the Imagic TGA WP Porros, available in 7× or 10× formats. These Japanese-­ designed models come with Opticron’s longest warranty of 30  years, so they’re bound to last a lifetime. Unlike the rather dated fold-down rubber eyecups on the Adventurer models, the Imagics have excellent twist-up eyecups, a much thicker and textured black rubber armoring and a click-stop diopter mechanism located under the right ocular lens. The optics are fully broadband multi-coated using the company’s proprietary F-coat that ensures light transmission levels of the of the order of 88%. My tests on both the 7× and 10× 50 models showed no annoying internal reflections when pointed at bright lights at night and no sign of diffraction spikes all to common on much more expensive roof prism models.

The Opticron Imagic TGA WP 7×50 & 10×50

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These instruments are both heavier than the more lightly built Adventurer T models, weighing in at about 820 g. That may sound heavy but it’s still quite light for a 50 mm Porro prism binocular. Indeed, a cursory look at some premium 8 and 10×42 models shows some of them to be heavier than these binoculars. The focus wheel is entirely different in the Opticron Imagic TGA binoculars though. It is more centrally located and is somewhat larger and thicker than those found on the Adventurer T models. Movement is slow but very smooth and devoid of any free play. That might sound like a negative if you intend to go birding with these instruments, but to be honest, they’re a bit overkill for such activities. Neither are their close focus distances conducive to regular birding either. I estimated both to have a close focus in the range of 5 meters. But none of this is important when stargazing and that’s where these instruments really shine. What distinguishes these instruments from cheaper models is their excellent edge-to-edge sharpness. And while their fields of view are on the small side (6 degrees for the 7× model and 5.3 degrees for the 10×50), it is just terrific to see shoals of stars as beautiful pinpoints across the vast majority of the field. Independent testing of a smaller model in the Imagic TGA WP showed that their light transmission is of the order of 88% – a very good result and a testament to the excellent coatings applied to the lenses and prisms within the optical train. Yes, these have quite flat fields of view, although they don’t employ field flatteners and this is very desirable for those who want pristine views of the night sky. Indeed, nothing is more frustrating than seeing nice sharp stars as tiny pinpoints in the center of the field only to be left disappointed with badly distorted star images near the field edges. How was Opticron able to do this? By keeping the field of view small; that’s it! Those who wear eyeglasses will be delighted to know that both the 7× and 10×50 Imagic TGAs have ample eye relief to accommodate their needs (21.5  mm and 19.5  mm, respectively), making them extremely comfortable to view through. Having both models at my disposal, I was able to conduct a thorough side-by-side comparison of their capabilities under dark skies. So how does the 7×50 model compare to the 10×50? Right off the bat, these binoculars are very comfortable to use. They fit nicely in the hands and the rubberized eye-cups are comfortable in the eye sockets. Both instruments are also tripod-mountable, using a standard L-bracket. Both these large aperture binoculars are extremely comfortable to look through, with no blackouts experienced while panning across a landscape. Close focus on the 7×50 was measured to be 5.6 yards while the 10×50 was slightly longer at 5.9 yards. Both instruments present nice, well-defined field stops, as well as instantly recognizable stereopsis. This is especially noticeable when viewing objects in close proximity to each other, such as in a forest, with the 10× glass being a little bit more pronounced in this regard. This is yet another feature I find particularly charming about Porro prism binoculars in that they readily deliver views with more spatial information owing to the larger separation of the objectives than in their roof prism counterparts. I had a particularly vivid experience of this stereoptic effect in the very early morning of August 7 2022, when I sat, completely enchanted, observing a magnificent dragonfly hovering over my brother’s garden pond in South Wales. The mist was still dissipating from the water’s surface in the cool of the morning, as I

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watched in sheer amazement its iridescent wings, bulging compound eyes and body glistening in the feeble, hazy sunshine some 10 meters in the distance. I became totally captivated by the dexterity with which it manipulated its two sets of wings, changing both their orientation and power stroke from moment to moment before accelerating at breakneck speed off into the distance. I later found out that these giants of the flying insect world have been clocked moving at more than 18 miles per hour! The 7×50 gives an ultra-stable viewing experience owing to its lower power, allowing the user to view for significantly longer periods of time. That said, I found viewing through the 10× glass to be the more immersive of the two, despite its smaller field of view (5.3 degrees as opposed to 6.0 degrees for the 7×50). Depth of field is noticeably deeper in the 7× instrument though. Indeed, having both instruments readily at hand, I conducted some measurements of this with the help of my son’s golf rangefinder. Carefully targeting well defined objects in the center of the field to minimize the effects of field curvature, the 7×50 unit delivered a close focus at infinity of 50.9 yards, while the 10×50 produced a value of 70.5 yards. In previous work, I fleshed out some of the details of the factors that influence depth of field, showing that the most important parameter was magnification and which scales inversely with power. I thus expected a (10/7)^2 or twofold greater field depth in the 7×50. Plugging the figures in yielded (70.5/50.9)^2  =  1.92, in close agreement with theory. Neat! Large aperture instruments such as these naturally come into their own in low light situations, such as late evening viewing. Observing at sunset, and about half an hour into the dusky twilight, I was readily able to discern that the 7×50 yielded brighter images of targets set in the shade, such as leaf litter under bushes. But here’s the thing; I was very impressed by how well the 10×50 was keeping up! Magnification is, of course, at play here, providing a more enlarged view of targets which partially compensates for the grater brightness of the lower power glass. I mean, what good is a brighter image if it doesn’t show detail? Although I could more or less instantly tell both instruments were well collimated in daylight tests, I was easily able to verify this under the stars. Centering the bright star Altair in both the 7×50 and 10×50, I turned the diopter setting to the end of its travel, defocusing the star from a tight pinpoint to a defocused anulus of light. Both instruments showed the focused star well inside the anulus, indicating that both instruments had their barrels well aligned. Turning to the Big Dipper, I took the opportunity to test the size of the field of view in the 10× glass by noting that the pointer stars (which show the way to the North Star, Polaris), Dubhe and Merak are precisely 5 degrees 21′ apart, or 5.3 angular degrees. I was delighted to see that both stars could just fit inside the field of view, so no discrepancy here with the stated field size. Impressive! While I was in this part of the sky, I took the opportunity to hunt down the two Messier galaxies in The Great bear – M81 and M82 – easily swept up by drawing an imaginary line from Phecda through Dubhe and extending that line as far again until I could see both galaxies close to each other in the same field of view.

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Comparing the views in the 7×50 and 10×50, it was immediately obvious that the 10× glass showed these faint fuzzies considerably better than the 7× glass. This is all textbook behavior for these binoculars. The 10× glass delivers ~0.5 magnitude boost over the 7× glass. The main reason is the larger magnification of the 10×50, which darkens the sky approximately (10/7)^2 or 2× greater than the 7×50, making these faint objects stand out better in the former. This is a very convenient way to see the immediate benefits of a 10×50 over a 7×50 under dark skies. But it was also obvious when I turned the binoculars over to the Alpha Persei Association in Perseus, where the 10×50 swept up more stars than the 7×50. The same was also clear from looking at the Double Cluster, located roughly midway between Cassiopeia and Perseus. Fainter stars could be seen in the 10× glass than the 7× glass. Bringing both the 7×50 and the 10×50 to a very dark site in rural South Wales during warm and settled summer weather afforded ample opportunities to do some quality stargazing. For the steadiest, deepest views, a monopod is recommended with either of these instruments, but on this occasion, I enjoyed simply handholding them while lying back on a zero gravity chair. Views of the Milky Way through Cygnus were breath-taking in both binoculars, particularly in the region around Sadr. What I really like about these binoculars is their very well corrected fields. As I’ve stated before, optical defects are much easier to see under the stars than during the daytime, when the eye tends to be overwhelmed by the amount of detail seen in and around the center of the image, but star images are less forgiving. Under some super dark skies and the Moon setting early in the first week of August, I could see that the central 80% or so of the field of these binoculars produced sensibly perfect star images, but in the outer 20%, the effects of field curvature began to manifest themselves. Thankfully, these aberrations were very mild, with the images nearly all the way up to the field stops still being acceptably small and sharp to my eyes. Indeed, the views very much reminded me of those served up by my largest binocular – the Pentax PCF 20×60 WP, with its aspherical eyepieces – only with a much wider field (5.3 compared with just 2.2 degrees). Images of the Moon in both binoculars displayed excellent contrast and sharpness, and I could detect very little in the way of chromatic aberration in the center of the field, with lunar craters peppering the southern highlands with impressive clarity. Off axis, a small amount of lateral color (mostly yellows and a splash of purple) began to creep in but that’s all par for the course in most any 10×50 you’ll look through. The formidable light gathering power of these high-quality Porro prism binoculars from Opticron proved very beneficial for enjoying the colors of bright stars. I enjoyed some magnificent views of the Pleiades in the wee small hours of late August, as well as M34  in Perseus, and the ghostly light from the Great Spiral Galaxy in Andromeda (M31). The Dumbbell Nebula (M27) in Vulpecula looked terrific too in the 10×50 but less impactful in the lower power of the 7× glass. The same was true when I turned the instruments on the Coathanger asterism (Brocchi’s Cluster) nearby. And moving back across the sky into Cassiopeia, I compared and contrasted the view of the ET Cluster in both instruments, with the victory, once again, going to the 10×50.

A 10×50 ED from APM

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The excellent sharpness and contrast of these binoculars proved ideal for observing colorful single, double and multiple stars, with the 10×50 coming out on top once again. Mu Cephei – Herschel’s Garnet Star – was compelling in deep red, as were the beautiful colour contrast binocular doubles O^1 Cygni and Delta 1 & 2 Lyrae sailing high in the late Summer sky. Colorful stellar associations, such as brilliant white Altair contrasted against the orange giant star, Tarazed, in the same field, were admired in all their preternatural beauty. I’m of the opinion that star images are more aesthetically pleasing through good Porro prism binoculars, owing to their complete lack of diffraction spikes. I came to notice this in comparing a few bigger roof prism binoculars with the 10×50, and in particular, a Vortex Diamondback HD 10×50. During daylight tests, for example, the Opticron Imagic TGA WP 10×50 produced crisper images with noticeably better contrast and less glare than the big Vortex roof. But that really didn’t surprise me as you’d probably have to fork out at least two or even three times more money to get a roof prism model that can compete favorably with these very well appointed Porro glasses. Under the stars though, the Diamondback HD did quite well, but didn’t quite deliver the same off-axis performance to the 10×50 Imagic TGA WP I compared it to. Eye relief is noticeably shorter on the big Diamondback HD too (16 mm). It was also a little bit heavier (~850 g) than the Opticron, which counts in extended hand-held use. Are there better Porros out there? Yes, the Nikon SE 12×50 comes to mind, or a Fujinon FMT 10×50, or even a classic Swarovski 10×50, but these cost several times more than either of these binoculars – if you can even get them. But if you can live with the smaller field of view offered by these instruments, you’re in for a real treat when you test them out in daylight or better still, under dark, starry skies where they’re in their element. Couple all this to their modest cost – both under £200 – and Opticron’s excellent 30-year warranty, and you may begin to see why it’s really hard not to like them!

A 10×50 ED from APM Another binocular held in high esteem among amateur astronomers is the APM 10×50 ED. This is a beautifully designed binocular with a magnesium alloy chassis overlaid by a textured leatherette finish giving it somewhat of a retro look, high-­ index BaK4 prisms, and an ED element in the objective to give crisp, high-contrast images. The APM ED also has some of the best anti-reflection coatings on the market ensuring very high light transmission. Somewhat unusually for an astronomy binocular, the eyepieces are individually focused, so not ideal for watching fast moving wildlife (it has a close focus of 6 m which is not ideal for birdwatching), but once adjusted on an astronomical target, you need only occasionally adjust these, as all astronomical targets are set at infinity. The instrument is fully water proof (IPX7 rating) making it a good choice as a marine binocular (see the next chapter for more on these instruments), offers a very generous 20  mm of eye relief and an

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impressively wide 6.5 angular field of view. Owners report nice tight star images nearly all the way to the field stops. All of these quality features means that its not exactly light weight at 1329 g, without the strap. The APM ED 10×50 retails for about $400 dollars plus shipping.

A Big ED Glass from Svbony In previous chapters I showcased some of the smaller members of the Svbony SV202 ED binoculars. They also market a larger 10×50 ED, which proved to be an impressive stargazing binocular.

The Svbony SV 202 10×50 ED

I immediately noticed the greater weight of the 10×50. I measured it at just 914 g without the strap and lens covers. That’s actually lower than the quoted weight of 951 g and rather good news if you like to handhold binoculars for prolonged periods of time. The coatings looked identical to those on the smaller models; a deep and beautiful magenta hue as seen in daylight. These anti-reflection coatings were applied very carefully and evenly, with no sleeks or pits. The larger 10×50 ED has very comfortable eye relief; good news for eye glass wearers. The textured rubber armoring affords excellent protection against the elements and makes the binocular very easy to grip and hold steady. And yet it is not overly thick, helping to keep its weight down. The focuser moves very smoothly an accurately, going through about three

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quarters of a turn from closest focus to infinity. Like the smaller models, the twist up eyecups are of excellent quality, rigidly maintaining their positions at each detent. In summary, this is a very well built binocular which handles well. To be honest, I was expecting great things from this 10×50 ED based on what I experienced with the smaller models. Did Svbony deliver? Yes, in spades! Performing my flashlight test on the 10×50 ED, showed another excellent, clean result. There was no sign of any significant internal reflections, no annoying diffraction spikes and no sign of inferior optical components causing the light to diffuse around the light source and cut down on contrast. Absolutely brilliant! Looking at some bright sodium streetlights at night showed zero problems with diffraction spikes, glare or internal reflections. “Will make a great Moon gazing ‘scope’.” I remember writing in my notebook. More on that later! Examining the eye pupils of the 10×50 ED showed great results, as you can see from the images presented below. Both pupils looked nice and round, with no annoying light leaks near them. I would rate this result as excellent. Well done Svbony! The wonderful light gathering power of this 10×50 presents a very large sweet spot, making the view especially delightful. Depth of focus was good for a binocular with these specifications and the close focus was astounding – I measured it at only 2.09 m – a jolly good result. Indeed, the reader will note that the close focus on the 10×50 is significantly shorter than the 10×42 model – which came in at 2.8 m in comparison. That’s actually considerably closer than many premium alpha models typically coming in at 3 meters or more! This remarkable result will make the 10×50 an excellent choice for those who like using their binoculars as long distance microscopes to study insects, leaves, rocks and fungi in glorious detail. Indeed, I’ve personally never heard of anyone using a 10×50 to do this kind of work! I received the 10×50 ED during a spell where a bright Hunter’s Moon graced the sky, drowning out the light from the faintest stars. Thus, I was unable to fully test the binocular as well as I had initially intended. But I was able to confirm some excellent results just by looking at the full Moon of October 20 2021, as a rash of blustery showers moved away inland from off the Atlantic. Comparing the 10×50 ED to the smaller 10×42 ED model, I immediately noticed how much brighter it was compared with the latter. Indeed, it was almost blindingly bright in the clear and dust free sky, swept clean of particulates. Just like the 42  mm model, the larger 50 mm served up a beautiful, high-contrast image of the lunar regolith, and once again, I came away with the distinct impression that the lunar orb was slightly larger in the 10×50 than in the 10×42. The image was free of glare and internal reflections, as my preliminary tests showed. Later, as more clouds began to move across the face of the Moon, I enjoyed some awesome light shows with the 10×50, with beautiful colors as the refraction of light through raindrops played out their magic, approaching and receding from the Moon. The grey maria really stood out cleanly as did several marble-white ray craters. I detected a trace more chromatic aberration in the 10×50 ED compared with the 10×42 ED model, a natural consequence of the larger glass gathering more light. But what little I did see was quite sensitive to eye placement. By taking an extra moment to center my pupils in the eyecups, I was able to make it all but disappear.

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Moving the Moon from the center to the outer part of the field did introduce some lateral color in both instruments but I judged this to be largely inconsequential. Turning next to the Pleiades, off to the east of the bright Moon, I was able to show at a glance that the 10×50 ED was pulling in more light as evidenced by brighter and more numerous stars compared with the 10×42 ED.  Turning to the magnificent Alpha Persei Association very high in the midnight sky, I was once again bowled over by how good and sharp the fields of view presented in both binoculars. Though this stellar association is large and sprawling, filling most of the field of view in these 6-degree field instruments, I was impressed by how well they focused the stars even in the outer part of the fields near the field stops. The cluster was that little bit more impressive in the 10×50 ED however, a natural consequence of its greater light gathering power. Bright white stars like Vega easily show up chromatic aberration in less well-­ corrected 10× binoculars in these larger formats, but on axis, both these binoculars delivered very clean, sharp and high contrast images with hardly a trace of false color. Again, only by moving the star off axis, did I see some secondary spectrum creeping in. That said, it was only slight and quite non-injurious to the aesthetics of the view, and I admit to liking a bit of the sparkly blue. Some modest bloating of the star did occur near the field stops in both instruments, but I consider this edge of field distortion to be quite acceptable for general star gazing. All in all, the 10×50 ED will make an awesome stargazing binocular, which can be enjoyed for decent long spells just hand held, but you’ll go a whole lot deeper by mounting it on a lightweight tripod or monopod. I’ve gone on quite a journey with these wonder glasses from Svbony! They have phenomenal optics that will surprise and delight even the most discriminating of observers, especially when you factor in their modest cost. To be frank, they are worth considerably more in my opinion, than what their modest retail cost suggests (the 10×50 model costs about $200). But that’s life; sometimes fortune smiles your way. I give these instruments my highest recommendation.

Big Roofs from Maven If big roof prism binoculars are your thing, you ought to at least consider the line of 10×50 binoculars marketed by the US based company, Maven. Their entry-level model comes with a ‘C’ labelling, while their more advanced products are all in the B series. The C3 10×50 comes in an attractive grey and orange polycarbonate chassis. The optical components for the C3 are sourced from both Japanese and Chinese optics houses and the instrument is assembled in the Philippines. Weighing 850 g, the C3 10×50 has a host of advanced features such as an extra low dispersion glass element in the objectives, a hydrophobic coating applied to the outer lenses, a full waterproofing (IPX6) as well as being filled with inert dry nitrogen gas to prevent internal fogging in low temperatures. Despite having a fairly narrow field of view just under 5 angular degrees wide, owners report a very sharp image in the center but also on the edges, with a close focus of just 2.5 meters. Chromatic aberration is

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also reported to be very well controlled on the C3 thanks to its ED glass billing. Light transmission is very high for such an entry level model – the company claim 90% transmission across the visible spectrum! That’s thanks to fully multicoated optical components and dielectrically coated Schmidt-Pechan roof prisms. The central focus is big and composed of metal overlaid with rubber armoring. The turning is slow but very accurate; all you really need for astronomy. The twist-up eyecups are decent and have a number of intermediate positions to suit most anyone’s eyes, whether wearing glasses or without. Eye relief is a comfortable 19.5  mm. Some users report that the eyecups can be a bit uncomfortable in prolonged use though. One excellent feature not found very often on roof prisms offered at this price point is that the eyecups can be screwed off to better access the eye lens for cleaning or if they get damaged or worn down. The C3 can be easily mated to a monopod or tripod to enjoy rock steady views of either the daytime landscape or the glories of the night sky. You get soft rubber oculars and objective covers, a logoed padded neck strap and a comprehensive user manual. The storage pouch is woefully inadequate to store these binoculars safely however, but I suppose Maven skimped on this to keep the overall price of the package as low as possible. On the plus side though, Maven offers a no-fault lifetime warranty with all of their products, which means you can be assured of getting a repair or a replacement of the binocular if you hit any snags. For a retail price of $475, you certainly get a lot of bang for your buck.

The Maven B.6 10×50. (Image Credit: Maven Outdoor Equipment)

Maven also market a more sophisticated 10×50 roof prim model in their B.6 10×50, which builds on the success of their very popular B1 line. Fans report excellent performance in the field, comparable, they say, to premium models that cost

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nearly twice as much. Compared with the C3 model, the B6 has a noticeably wider field of view (6.5 degrees), amazing light transmission (94.8%), and a higher waterproof assurance (IPX7). Considered one of the brightest mid-sized binoculars in the market today, they are built to maximize optical light gathering for an improved overall glassing experience. The polycarbonate chassis on the C3 is replaced by a more robust magnesium alloy on the B6 chassis, but all the while keeping the weight down to just 870  g. You also get a choice of two colors on the B6 model; grey-­ orange or just grey. This kind of quality demands high standards, explaining its entirely Japanese design and place of manufacture. But expect to pay more than the price for this very high-level performance – $1050. One more thing: both the C3 and B6 models are accompanied by higher power siblings in 12×50 configuration should you require more magnification.

A High-Powered Light Cup from Pentax The achromatic telescope has enjoyed a long and illustrious career in the hands of skilled observers. In my historical work, Chronicling the Golden Age of Astronomy, I have documented and shared with you the amazing achievements of the classical refractor over three centuries of time. But it would be quite inaccurate to claim that it has been really superseded by anything else in the modern age. This is especially true in the case of binocular manufacture, where sales of achromatic instruments still vastly outsell models which possess modern ED glass. And there’s a good reason for this: ED is an expedient luxury that impacts little to the binocular view, what with their low magnifications and wide fields. For every ED model offered, there are a great deal more made with traditional crown & flint, and that is true even for some premium brands, especially in the smallest apertures. Take for example, the venerable Leica Ultravid 8×20 and 10×25, or my personal favorite, the Nikon EII 8×30 discussed in earlier chapters.

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The Pentax PCF WP II 20×60

We still live in the achromatic age. Having enjoyed and appreciated the achromatic refractor for decades, I have come to the conclusion that it’s in the binocular that achromatic optics has reached its zenith. Properly made, achromatic optics provide wonderful, sharp and contrasty images of the natural world. This conclusion has been reached by extensive field experience of a variety of achromatic binoculars that show vanishingly small amounts of secondary spectrum and which are far more alike than different to models with ED glass, but at a fraction of their cost. These sentiments are also reflected in the models still being marketed by some big names in the large binocular world, including Celestron, Fujinon and the earlier models marketed by Oberwerk. What these manufacturers offer is great performance at prices that won’t leave you out in the cold. For certain kinds of visual astronomy, large binoculars simply can’t be beaten. The ability to use two eyes rather than one greatly influences the quality of the views, where it impacts depth of field perception, faint object detection and significant improvements in perceived contrast. Without a shadow of a doubt, large binoculars are the single most powerful way to enjoy larger deep sky objects, where telescopes simply cannot offer the same ‘zoomed out views.’ That said, it’s very much a Goldilocks scenario; increase the magnification too much and you lose those gorgeous panoramic sights, but when the power is too low, finer and fainter details remain elusive. It was with this realization that I took a punt on a curious large achromatic binocular made by Pentax; enter the PCF WP II 20×60. That Pentax were prepared to put their name on the PCF WP II 20×60 is a lesson in objectivity. Why would such a prestigious manufacturer of high-end cameras and

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sports optics decide on a well-appointed, large achromatic binocular? The answer is that when well made, even a 20× model would deliver wonderful, tack sharp views of the landscape by day and breathtaking celestial vistas by night. And this has been achieved at a price point that suits the budgets of discriminating amateur astronomers, who just appreciate well designed classical optics. Though the instrument can be acquired at a good, price new (£250 UK for the latest SP model), I was lucky enough to acquire this binocular in excellent, used condition for a little over half the retail price. The former owner had taken very good care of it, added a sturdy carrying strap and dispensed with the flimsy carrying case, replacing it with a sturdy foam-lined aluminum case. This large Porro prism binocular weighs just 1.4 kilos (~3 pounds), surprisingly light for an instrument of these specifications and is water and splash proof. This may account for the WP (water proof?) in their name. The interior is purged with dry nitrogen gas to prevent internal fogging and to minimize corrosion. The body, which is constructed of a lightweight magnesium alloy, is covered with a protective rubberized substrate that is easy to grip and is tough and durable in all weathers. The optics are fully multi-coated to maximize light transmission to the eye and to reduce contrast-robbing internal reflections to a minimum. The center focusing wheel is remarkable in two respects. Firstly, it’s quite tight in comparison to other binoculars I’ve used. This was intentionally done by the manufacturer, as you’re not likely to use this instrument watching fast moving birds or some such, necessitating the rapid change of focus position. This increased tension does however allow for very precise focusing to be achieved. Secondly, there is a facility on the focuser to lock it in place. Simply push the focusing wheel forward and it’s locked in; a nice design feature that can be advantageous. For example, if you end a session with the binocular focused on the stars at infinity, locking the focuser in place ensures that you can re-engage with the sky whenever you’re next out, with minimal (if any) re-­ focusing necessary. The strong bridge connecting both barrels of the binocular is reassuringly stiff, allowing one to easily obtain the correct inter-pupillary distance (IPD) and only requires occasional adjustment in field use. The diopter setting is found under the right-hand eyecup allowing independent focusing of both barrels. It has just the right amount of tension and stays in place without any fuss. I really like the twist up eyecups on the Pentax PCF WP II 20×60. Like my smaller binoculars, they click into place and are quite secure. Eye glass wearers just need to hold the eyecups down, while those who don’t (yours truly included) can extend them upwards for very comfortable, full-field viewing. The texture of the cup is hard rubber which is a far cry from the cheap fold up/down eyecups seen on many other large binoculars in this price range. Indeed, it is my experience that the latter can fragment in prolonged field use, necessitating their replacement from time to time. These sit very comfortably against the eyes and never need to be adjusted. Eye relief is exceptional; a very comfortable 21 mm. It’s not the weight per se that forces one to mount this instrument. As stated above, they are quite light for their optical specification. Rather, it’s the 20× magnification that limits their hand-held use. That said, I can hold them reasonably steady

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by extending my hands a little further forward on the barrels than with my smaller binoculars and this strategy can work quite well for short, ‘quick peek’ sessions. Incidentally, I discovered thumb indentations on the belly of the instrument presumably designed to assist hand holding! Golly gosh! Still, whatever jitter you have, it will be magnified 20 times while looking through it. Such high powered binoculars definitely require some kind of stabilizing action and, in this capacity, one can either elect to use them tripod-mounted or by using a monopod. A word of caution; avoid using those cheap plastic tripod adapters that often attend bargain basement large binoculars such as the ubiquitous 15×70. These introduce an annoying level of flexure that will almost certainly detract from enjoying the instrument in the field. It’s strongly advisable to invest that little bit more in a good quality, all-metal unit sold by Opticron and other companies. Indeed, I found the same adapter that fits my 10×50 roof prism binocular also works swimmingly well with this larger instrument. Tripods have their pros and cons though. Although they offer the maximum level of stability and have built in slow-motion controls on both axes, they are fine for terrestrial viewing where the angles of elevation are not too severe, but become quite uncomfortable to use when aimed high in the sky. I found it quite hard to find a suitably comfortable positioning of my eyes when used in the seated position. That said, a tripod was useful in checking collimation of the barrels and certain daylight activities, but in the end the most suitable way I’ve found to use this instrument is by mounting it on a simple monopod. Using a high quality (solid aluminum) ball & socket adapter, mounting the 20×60 on a monopod is quick and easy to execute. Using the monopod, I have been able to get very stable views during daylight and extended periods of night use. For quick looks, I usually stand and adjust the angle of either the monopod itself or the ball & socket head. For the most stable viewing sessions however, I relax in a recliner and, securing the monopod base between my feet, have attained nearly jitter-free viewing. I have learned to place some of the weight of the binocular on my face, which increases the overall stability to a significant degree this works great for both stargazing or long-range birding activities. As the size of binoculars increase, it makes a lot of sense to decide on a Porro prism design, rather than their roof prism counterparts. Porros are less expensive and just easier to make well and, at least in the low to mid-priced range, also offer slightly more light throughput than their roof prism counterparts. The optics of the Pentax PCF WP II 20×60 are notable. All lenses are fully multi-coated with a protective overcoat. The BaK-4 prisms are also multi-coated. The oculars are constructed from aspherical lenses which offer several advantages over conventional lens systems, especially in the suppression of spherical aberration and a number of off-axis aberrations that plague conventional Porro binoculars. In addition, fewer elements are needed with aspherical designs, significantly reducing weight. Rather than rambling on with this, it’s best to hear it from an established optics firm.

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Collimation of binoculars is important especially on these high-power units. One quick way to test for collimation is to mount the binocular on a tripod and select a bright star. Focus the star as tightly as possible and then rotate the diopter ring until you see a fuzzy egg-shaped disk. If the binoculars are collimated properly, the tightly focused star in the left barrel should sit on or inside the defocused star image. If it’s not, then you have a collimation issue that needs to be rectified if you intend to do any prolonged observing with this instrument. Thankfully, this particular instrument was nearly spot on, so no misalignment issues here! Misaligned prisms can also be revealed by examining the shape and size of the exit pupil when the binocular is pointed at a source of light. In my tests, both exit pupils were perfectly round and of the same size indicating that all was well. Daytime tests: The binocular has a 3 mm exit pupil, nearly the maximum resolution value for the human eye. This ensures the best part of your eye is sampling the field. And oh what a field! When precisely focused images of daytime targets are bright and tack sharp across nearly the entire field (read 95%), indicating that that aspherical optics were working well. Contrast is excellent with very effective baffling of stray light. On axis, there is some color fringing as you’d expect from a binocular of this specification but to my eye at least, it’s not in the east bit distracting. I could see that off axis some lateral color was evident. That said, it was modest and totally acceptable to my eye. In comparison to a side-by-side test made with my ShortTube 80 f/5 achromatic telescope charged with a power of 16× (5 mm exit pupil) in a wider 3.75 degree field showed much higher levels of lateral color. Close focus was estimated to be about 8.5 meters. For nighttime testing, I mounted the 20×60 on a simple monopod, as described previously. This is a very quick and effective way to get going with these large binoculars. Some users of the instrument complained about the small field of view offered by the Pentax PCF, what with its 2.2 degree true field. Others commented on the sensitivity of the instrument to eye placement, but truth be told, I found neither of these things to be in the least bit distracting. You see, I’m used to very small fields working with close double stars at very high magnifications and with fields that are far smaller than what is offered by this big gun. Right off the bat, I was enjoying very comfortable, stable images. A 2.2 degree field is small as 60 mm binoculars go, but it is plenty good enough to frame larger deep sky objects. To my mind, it simply boils down to training. My first light target was the Pleiades cluster in Taurus. Getting myself comfortably positioned on my recliner and adjusting the monopod, I was absolutely blown away by the sight of this magnificent open cluster in the 20×60! More like an Astro photo than anything else, the entire cluster was beautifully framed, crammed full of gorgeous blue-white starlight and razor sharp from edge to edge. The sky hinterland was jet black with none of the flaring of stellar images that I had experienced in my brief rendezvous with budget 15×70 models. It is immediately apparent that the field is very flat from edge to edge, with no distortions that I could register. It just exuded quality! And although I own a number of good telescopes that can collect far more light than this 20×60 instrument, they could not beat it in terms of delivering

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such a magisterial image. Focusing the binocular was particularly satisfying; because of its very shallow depth of focus very small motions can make the difference between seeing the faintest stars and not seeing them at all. Turning next to the Sword Handle in Orion, which is also perfectly framed in the 2.2 degree field, I was deeply impressed at the wonderful contrast and color rendering of the bright O/B stars in the field; tiny little pinpoints of light bathing my retinas. I could easily make out the greenish hue of the great Nebula in Orion (M42) and a steady hand revealed at least two of the tiny quartet of stars comprising the famous Trapezium (Theta Orionis complex). Though the field of view is not large enough to frame the three bright Orion belt stars, the 20×60 pulls out many more faint stars in Collinder 70 that are quite beyond the reach of my regular astro binocular; my trusty 10×50. Suddenly, this preternaturally lovely open cluster has become a whole lot more crowded! In the wee small hours of freezing January nights, I would watch the sky, waiting for the Beehive Cluster (M44) in Cancer to approach the meridian. Having experienced the Pleiades, I was very much looking forward to seeing this large and sprawling open cluster in the 20×60. And again, it did not disappoint; the view was enthralling! The entire field was filled with pinpoint stars against a jet-black sky. Using two eyes greatly enhances the view and there is a lot to be said for seeing these wonders of in their correct orientation, as if they were made for such instruments. The 20×60 is tailor-made for objects such as the Double Cluster in Perseus, which was an absolute joy to behold in this high-power binocular; great mounds of starlight of varying hues with curious fans and spirals of distant suns meandering their way from their crowded centers. Compared with a 10×50, the view was simply in a different league! I didn’t notice much in the way of chromatic aberration in the images, save for a brief spell with the Dog Star, Sirius. Its brilliant light is dazzling in the 20×60, coruscating with various colors from moment to moment. In my opinion, secondary spectrum is a complete non-issue with this instrument for astronomical use; just set it up and go stargazing!

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A Great Performer under the Stars

Although smaller deep sky objects are best examined in telescopes with more light gathering power and their ability to take higher magnifications, I nonetheless enjoyed some very pleasing views of the Auriga trio of Messier open clusters; M36, M38 and especially the sumptuously rich M37, which appears satisfyingly large, well defined and glistening with the light of many faint suns. M35 was also big and prominent in this large binocular with dozens of its constituent stars being easily made out. This is a wonderful instrument for framing and observing the Engagement Ring: a circular arrangement of faint stars encrusted with the creamy bright Polaris as the principal gemstone. Smaller, more conventional binoculars really don’t show this structure half as well, owing to their lower power, wider fields and reduced light grasp. With such a large and powerful binocular, the colours of stars really stand out; marmalade orange Propus, sanguine red Mu Cephei, the soft yellow pastels of Capella and the Orion belt stars, white as the driven snow. This instrument would also make a dedicated variable star observer very happy, what with its impressive light gathering power (reaching down to perhaps+11 magnitude from a dark site with good transparency) in a very well corrected, wide field. The 20×60 might not be the first instrument that comes to mind for a budding comet hunter, but I am reminded of the advice of the great nineteenth century observer, William F. Denning, recounted in my historical work, Chronicling the Golden Age of Astronomy, who recommended an instrument with a field of view of between 1 and 1.5 degrees for

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such work. And in more modern times, the distinguished comet discoverer, David H.  Levy, advises that the comet-seeking instrument delivers a field of just 0.75 angular degrees! Seen in this light, the suggestion doesn’t seem quite so far-fetched. The big Pentax glass provides wonderful views of some prominent binocular doubles; Mizar & Alcor, o1 Cygni, Albireo, Mintaka and Cor Caroli, to name but a few. The Pentax PCF 20×60 is a formidable instrument for delineating structures within larger asterisms. Just have a look at the stars around fiery red Aldebaran with this bazuka! Sure, you can’t see the entire Hyades but with its pinpoint stars, wonderful contrast and generous ‘space penetrating power’, as Sir William Herschel of old liked to say, it allows you to capture painfully beautiful star fields, rich in light and color against a velvet black sky. It’s even more amazing when pointed at Alpha Persei; the field is littered with lovely stellar jewels sparkling through the cold dark of interstellar space. This will be a great instrument to begin a study of stellar hinterlands around the brightest stars in general, something I thought about in the past but never pursued because of other diversions. I think it’s tailor made for such projects! Starting in Gemini and running the binocular haphazardly across the sky through Auriga, northern Orion, Taurus, Perseus and ending in the gloriously rich Cassiopeia, the binocular shows me many new asterisms which I had not witnessed before, a consequence of its unique field of view, magnification and image orientation. Almost every field stumbled upon brings new bounties, delicate arrangements of stars unnoticed in smaller binoculars; vast shoals of starlight in the open ocean of space. In the early days of February 2019, I got several opportunities to observe the waxing crescent Moon through the monopod-mounted Pentax PCF 20×60 binocular. The views were amazing; razor sharp, beautiful contrast, most excellent suppression of internal reflections that can easily plague lesser binoculars. Indeed, I’ve devised this simple but highly discriminating test as a way to quickly establish whether a binocular is fit for general astronomy use. If the unit shows flare and/or internal reflections when pointed at the Moon, it’s leaking light. The image scale of the Moon seemed larger than I expected it to be in going from a standard 10× binocular to this 20× unit. It just seemed like I was getting a higher power than the 20× marked on the Pentax binocular tube. This is no doubt an illusion, a consequence I suppose of the Moon‘s taking up a larger fraction of the area of the field than seen in a traditional 10×50 binocular. The earthshine from the dark side of the Moon was very prominent and as the crescent continued to grow, the binocular revealed more and more details of the lunar regolith. The image scale is great for seeing high resolution details of the battered southern Highlands. On the evening of February 10, I enjoyed a wonderful view of the three large craters; Theophilus, Cyrillus and Catharina on the eastern shore of Mare Nectaris. Up north, Atlas and Hercules could be clearly made out with a steady hand. The limb displayed a sliver of color; sometimes green, sometimes yellow, depending on where my eyes were positioned. I judged the chromatic aberration on this tough target to be minimal and completely non-intrusive to a seasoned telescopic observer. Contrast between the bright lava fields and darker

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maria was very well presented, producing an extremely immersive, aesthetically pleasing view. This will be a great binocular to observe the early waxing Moon during March and April, when earthshine is at its most prominent and I look forward to fielding the instrument for this purpose. Sure, the binocular cannot substitute for the telescope proper, but it certainly complements those high-power, high-resolution views. The big binocular has a charm all of its own and should really be enjoyed on its own terms. As you can probably discern from the above write up, I took to this instrument like a proverbial duck to water! Less experienced observers have complained that the binoculars have too small a field, but I am reminded of the superbly designed (but very expensive!) Takahashi Astronomer 22×60 binocular (discussed later in the book) which sported a field of view of just 2.1 angular degrees, so slightly smaller than that offered up by the Pentax 20×60! The binocular is ideally suited to framing showpiece deep sky objects for careful study, such as the Double Cluster, the Pleiades, the Beehive Cluster and other large Messier objects, but is also well appointed for use in comet hunting/observing and variable star work. Its high magnification and excellent contrast produce magnificent views of the Moon that will impress anyone who uses it. By attaching homemade white light solar filters, I use the 20 ×  60 to regularly observe the solar disk. The Pentax PCF 20×60 WP II can also be employed as a two-eyed spotting scope in long-distance daylight viewing/surveillance, e.g. observing a bird’s nest at a comfortable distance or in a variety of maritime applications. Its very reasonable retail price makes this a most attractive instrument for budget conscious amateurs who do not want to compromise on optical performance.

 he Celestron SkyMaster 15×70: Affordable Large Aperture T for the Masses The Giant Celestron 15×70 Skymaster binoculars offer very good on-axis performance at an incredible price (~$70). Designed for astronomical viewing, SkyMaster binoculars delivers a 4.4-degree field of view and its large 70 mm objective lenses bring star fields, Jupiter and its moons, Saturn’s rings, and globular star clusters into clear view, affording you a unique peek at the universe. What is also fantastic about this Celestron binocular is its versatility as they can also be used for other uses including bird watching over longer ranges and wildlife viewing or any other terrestrial use that requires long distance observation. The 15×70 Skymaster also feature decent quality BaK-4 prisms and have multi-coatings for enhanced contrast and to transfer the maximum amount of light to your eyes. And from dark-sky environments, even objects like fainter galaxies and nebulae are within reach of this nifty binocular lightcup.

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The Celestron Skymaster 15×70 on a lightweight tripod

The Celestron SkyMaster 15×70 binocular is water-resistant and has an adaptor allowing it to be fitted to a standard tripod fitting. Other features include a protective rubber covering for ultra-firm grip, a large center focus dial for easy focusing, long eye relief ocular lenses ideal for eyeglass wearers and a soft case included for travel and safe storage. The Celestron No Fault Warranty gives you peace of mind with one of the best protection and product support on the market. Though the Celestron SkyMaster 15×70 was introduced a few decades ago, a few clones of this highly successful product have come and gone over the years. In preparing for the writing of this book, this author bought in the latest rendition of this binocular for a fresh look. While it’s unquestionably a large binocular, it’s not all that heavy. My sample tipped the scales at 1251 g, so quite light for this configuration. During the day, the SkyMaster 15×70 produced bright and sharp images, with very good contrast. I could instantly see how it’s so popular as a long-range optic, for studying targets in the far distance. Collimation was perfect – unlike what I’d seen on some of the Celestron clones I’ve used in the past – and close focus was measured to be about 14.17 meters. The central focus wheel is covered in textured rubber and rotates very smoothly with no free play or backlash. The diopter adjustment is located under the right eyepiece. It moves with a fair amount of friction, ensuring it won’t wonder during use. The large achromatic doublet objective has immaculately applied multi-coatings contributing to the bright image and high contrast views. The SkyMaster has a big sweet spot in the center of the image but does show significant softening at the edges of the field, mostly in the form of field curvature. This is courtesy of the binoculars longer than average focal length of 280 mm, making it a very decent f/4

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focal ratio. Of course, a large light cup like this really shines under a clear, dark sky. To get the best use out of it, it needs to be stabilized on a monopod or lightweight tripod. The package I received also included a decent quality tripod adapter but I’d encourage folk to invest in a higher quality unit, made out of machined metal rather than hard plastic. Examining the exit pupils of the instrument, I was delighted to see that they were round and untruncated. When I directed a bright light through the ocular lens and measured the size of the resulting disk projected onto a flat surface, I measured its diameter to be about 63 mm. That didn’t come as a big surprise though, as these budget instruments are known to have stopped down optics. I did not however consider this to be a serious handicap though, as the instrument still lets through a large amount of light. In another test, I tested for ghosting and internal reflections by turning the SkyMaster 15×70 on a bright sodium streetlamp in the distance. I did detect some minor reflections, but they weren’t that prominent based on some other instruments I’ve tested. Star testing on bright stars showed that the inner 50% of the field shows very nicely focused stars, but as one moves further out, the effects of field curvature astigmatism and coma gradually increase. The outer 20% of the field is pretty much unusable but that’s a small trade off considering what the binocular can show in the middle of the field. Let me explain. Views of the Moon are spectacular in the Celestron SkyMaster 15×70. Its intensely bright silvery surface is tack sharp with excellent contrast. A modest amount of chromatic aberration can sometimes be glimpsed at the center of the field but I found that it was very sensitive to eye placement. Internal reflections were very minor and weren’t in the least bit intrusive. The vast crater fields of the southern highlands were beautifully rendered as were the mountain ranges and ray craters peppering its ancient and battered surface. This is also an excellent instrument for observing earthshine on the crescent Moon when it’s particularly prominent in March and April. With a steady view, the tiny globe of Saturn can be glimpsed as well as its magnificent ring system. Jupiter can also be glimpsed as a tiny globe together with its four large Galilean moons. You can watch them change from hour to hour and from day to day. The very generous field of view is perfect for framing large open clusters. The Pleiades is stunning through this large binocular, as is the Double cluster in Perseus and the Beehive Cluster in Cancer. I enjoyed a spellbinding view of the Sword handle in Orion on a frosty December night, the sheer brilliance of the belt stars and the great Orion Nebula beneath them. Another great use of this 15×70 is white light solar observing. The 15× magnification provides a very decent-sized solar disk to allow you to clearly see any sunspots present on its surface. I’ve used my own home-made filters fashioned from a sheet of Baader Astrosolar material, placing them over the large 70 mm objectives to get excellent views of our nearest star. In summary, for the modest price paid for this binocular, the Celestron SkyMaster 15×70, certainly represents great value for money. Some critics have noted that many of these units get whacked out of collimation all too easily. Fortunately,

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re-­collimating this instrument is relatively straightforward, using a simple screwdriver to turn two screws (one for vertical movement and the other for horizontal adjustments) which are easily accessed under the rubber armoring of the binocular. You can find several YouTube presentations to see how it’s done. Doubtless, a savvy and resourceful individual can achieve a great deal with this economically priced instrument, whether it be deep sky observing, comet hunting, solar observing or studying a bird’s nest from afar. it’s simply imagination limited!

Top Performers from Fujinon Ask any seasoned binocular astronomer which brand is best for general stargazing and chances are the name Fujinon often trips off the tongue. One such amateur astronomer is Richard Duff, from Derbyshire, UK, who has used two Fujinon models for over a decade and still swears by them. Richard spoke to me about his two models: the 16×70 FMT-SX and the smaller 10×50.

The Venerable Fujinon FMT-SX 16×70. (Image Credit: Richard Duff)

“The 16×70 FMT-SX is often thought of as the reference standard for this size of binocular for astronomy, though over the last few years there have been some very good quality imitators produced that are not far off. Its outstanding feature for astro use is the superbly corrected field. Stars are pinpoints out to around 90% of the

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width of the field of view. Even the last 10% is still useable. Contrast is also outstanding, if a little more difficult to measure. Faint, low surface brightness objects like M33 and M101 “pop” from the background more easily than in other instruments. Sky background is perhaps a tad darker. It’s subtle but noticeable to the experienced eye. Glare suppression on the 16×70 is good; there is a little glare if the Moon is placed just beyond the field, but it’s minor. On-axis they are wonderfully sharp and focus down easily to pinpoint stars. One of the best things about them is the mechanical quality however. They exude a solid feel and the hinge and focus mechanism is firm yet smooth. I should add mine are the older black and yellow model from around 2000. They are slightly heavier than the newer version. Chromatic aberration seldom a problem for astro users of binoculars is actually quite bad in the 16×70, by day it can show quite a bit of it. Any high contrast situation will show yellow or violet fringing readily. Not too much of a problem for astro use but it’s worth noting if the intended use is daytime observation. These were famous for their electron beam coatings that are blueish in tone on the 16×70, but show almost no reflections even in bright daylight, something that must be helping the outstanding contrast. The 10×50 I think was added later on to the series, around the mid-2000s when Fujinon realized that amateur astronomers loved the FMT line, even though they had originally been aimed at the commercial fishing industry. They are only available in the newer green trim and are now only available I think in the rubber covered version, the leatherette version I have being discontinued. They are very similar in performance to the 16×70, but in my opinion even better. They seem even sharper on axis, have even better edge of field correction (they are sharp out to around 95+% of the field) and contrast is better yet than the 16× model. It is astonishing how good the contrast is in these, I have seen M101 from quite light polluted sites with them with little trouble. The Crab Nebula is easy. I believe the coatings were updated at some point. They are less blueish than the 16× and a tad more purple. They reflect even less light than the 16×. If they have one weakness, it’s stray light. They show a fair amount of glare in certain situations and when panning across the night sky beneath a bright star like Capella or Vega, a ghost image of the bright star will transit diagonally across the field. I think this is due to the “baffle cone” being a tad short in the barrel and not extending close enough to the prism cluster. The ghost image transits diagonally because it is a reflection from a prism edge, which is set at that angle in the binocular. Interestingly, this issue is not seen in the 16× model. It’s not a major problem and doesn’t seem to affect contrast negatively. I have actually made two 10″ long dew shields from black packing foam for them which reduce the intensity of the ghost image by about 3/4. They look faintly ridiculous but what do I care when I’m out on my own at night?!

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The superlative Fujinon 10×50 FMT-SX. (Image Credit: Holger Merlitz)

I will just mention apparent fields lastly, the 16× has around 64 degree (rough calculation) which is pretty wide. But the 10×50 is noticeably wider. Ed Zarenski at CN measured them at around 70 degrees as they are actually a 10.4× and the field is wider than advertised at 6.7 degrees. The end result is a beautifully wide, immersive and exquisitely well corrected field with outstanding contrast. Sweeping the Milky Way is a wonderful experience. There is a little magic in the 10×50 and it’s the one I would never sell, it’s that good.”

Realm of the Giants If you think astronomy binoculars can’t get any bigger, think again! They grow bigger, much bigger! Let’s take a look at the budget end of the market first. Celestron offer a range of very economically priced binoculars in apertures between 70 and 100 mm. We already discussed the deservedly very popular SkyMaster 15×70, but Celestron also offer a substantially larger model in the same series in the 20×80 which retails for about $129. Like its smaller sibling, the SkyMaster 20×80 features multicoated optics for bright, high contrast images. The higher magnification however, delivers a smaller field of view but it’s still quite decent at 3.7 degrees. The larger lenses and prisms add quite a bit more heft to this binocular, tipping the scales at 2126 g, so this will require stabilization using a tripod. Performance-wise, these binoculars passed nearly all the basic tests with muster. Central image sharpness is very sharp, with good contrast and good control over color fringing, with stars appearing circular (and not distorted) when out of focus. These giant binoculars serve up great views of the showpiece deep sky objects such as the Pleiades and Beehive Clusters rivaling any through a small telescope, except that you’re getting that added boost from using both eyes. That said, there was some significant color

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fringing around the lunar limb as you’d expect from a binocular with these specifications. Like the smaller 15×70, image quality drops off outside the sweet spot, but not nearly so much as the smaller Celestron. That’s because the diffraction limited area of the smaller field of view of the 20×80 is larger.

The Celestron SkyMaster 20×80

I spent an evening test-driving a well collimated celestron SkyMaster 20×80 with a local amateur astronomer The first quarter Moon was quite simply stunning, with beautifully delineated shadows along the terminator. Crater details were also excellent are also visible. Turning to the Giant Planet, Jupiter, all four of its large Galilean satellites were picked off very easily, but you won’t see anything on the planet itself. 20× is just not high enough to provide enough contrast to see any band details in its turbulent atmosphere. I was a little surprised with Saturn though, located quite close to Jove in the autumn autumn night sky. Unlike my 20×60 Pentax SP, I could not make out a clear disk with its magnificent rings. Rather it just looked like Galileo once saw it; elongated with ‘ears’. A big, powerful binocular like this provides a ring-side seat on innumerable double stars that we visited. Albireo (Beta Cygni), consisting of a bright, golden-yellow primary star and a fainter, blue secondary star. Mizar and Alcor (Zeta Ursae Majoris) – easy to find in the Big Dipper. Mizar is the brighter of the two stars, and can actually be resolved into a double star itself with a higher magnification (about 30× required).

Realm of the Giants

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Gamma Andromedae – This double star is located in the constellation Andromeda. It consists of a bright, white primary star and a fainter, blue secondary star. Epsilon Lyrae  – located near the famous Ring Nebula. It is also known as the Double-­Double, because each of the two stars can be resolved into a double star with a higher magnification telescope. Theta Cassiopeiae – This double star is located in the constellation Cassiopeia. It consists of a bright, white primary star and a fainter, blue secondary star. Since a 20×80 binocular can theoretically reach about magnitude 12, the views of Milky Way sweeps through the autumn sky were truly awesome! That being said, while these are fine for astronomy (after all, that’s what they’re made for) they’re not really recommended for terrestrial viewing unless its over very large distances. For one thing, they have a close focus distance of about 33 m, so you won’t be able to focus on anything in your vicinity. Secondly, these binoculars are a little too heavy to be hauled about, as you’d do with smaller binoculars. They’re just not designed to be taken on hikes or hunting trips. Beginners should avoid an instrument this big or bigger, as they might be biting off more than they can chew! If you think 20×80 is big, wait till you see the biggest binocular in Celestron’s line up; the SkyMaster 25×100! Here we get a completely different design philosophy. You see, as the magnification grows ever higher in a binocular the more difficult it is to collimate accurately. Coupled to this is the necessity to rigidly hold the barrels in place so it’s not surprising that larger binoculars have to be bult much more solidly, increasing their weight in the process. Celestron’s SkyMaster Series of large aperture binoculars are a phenomenal value for high performance binoculars ideal for astronomical viewing or for terrestrial (land) use – especially over long distances. Each SkyMaster model features high quality BaK-4 prisms and multi-­ coated optics for enhanced contrast. Celestron has designed and engineered the larger SkyMaster models to meet the special demands of extended astronomical or terrestrial viewing sessions. For maximum stability and secure optical alignment the 100 mm SkyMaster model features enhanced structural reinforcement to the main binocular body. As an additional convenience, the 100 mm SkyMaster model also includes an integral super rigid photo tripod adapter. The SkyMaster Series binoculars are built to provide years of magnificent views of the world around you and the heavens above. The fold-down rubber eyecups offer 15 mm of eye relief, so should work OK with those who have to wear eyeglasses. The instrument offers up an impressive 3-degree field, so large enough to frame many deep sky objects easily. The eyepieces on this instrument are individually focusing, so no need for a separate diopter compensation mechanism. Some owners have complained about how difficult it is to adjust the IPD for your eye settings. The best kind of mount for the Celestron Skymaster 25×100 binoculars is a sturdy and stable tripod mount. Due to the weight of these binoculars (3.97 kilos), it’s important to use a heavy-duty tripod that can

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support their weight and provide a stable platform for viewing. A good option would be a tripod with a large and sturdy head that can handle the weight of the binoculars without any wobbling or instability. If you don’t adequately mount this binocular, you’ll soon tire of it! Check out my Chap. 26 on binocular accessories for some examples of the kind of mounting options that are available. Optically, these deliver crisp images within its sweet spot, which is quite large in this instrument. Views of the Moon are quite simply stunning in these large ‘4-inch’ aperture binoculars. I’ve personally enjoyed some of the best views of the Orion Nebula (M42) with this giant instrument. The Andromeda Galaxy also looks brilliant in these binocular light cups. Of course, everything you can enjoy in the 20×80 binocular looks even more spectacular through this instrument. You’ll also be able to make out the phases of Venus with this binocular although chromatic aberration might ruin the view for some (Venus is a killer for color fringing, even in ED models!). The supplied nylon carry case is next to useless though; better to invest in a proper hard case to protect your binocular. The 25×100 retails for about $215. Now that’s what I call great bang for buck and a very decent introduction to large binocular astronomy. Finally, Celestron offer some of their models in the Pro series, with upgraded ergonomics and optics for a higher price. Check them out online!

High Power Optical Performance from Oberwerk While the Celestron SkyMasters satisfy the needs of many amateur astronomers, more discerning folk may tire of using them. Thankfully, going a step up in quality needn’t cost the earth. That’s where Oberwerk can fill that void. For nearly a quarter of a century, Dayton Ohio-based Oberwerk has been supplying very high-quality binoculars that cut well above the usual entry-level gear the masses tend to go for. But if large binocular astronomy is your passion, Oberwerk is sure to impress. We’ve already covered a few smaller binoculars from this company, but it’s in the large binocular world that Oberwerk excels.

High Power Optical Performance from Oberwerk

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The Oberwerk 20×65 ED Deluxe. (Image Credit: Oberwerk)

The 20×65 ED Deluxe binocular was launched in 2018, are built around a pair of 65 mm f/6 doublet ED objectives. That’s a nice, slowish focal ratio that’s easier on eyepieces. A lot of binocular astronomers were surprised with these specifications. Usually, 20× binoculars come in 70 mm or 80 mm apertures. The smaller 65 mm aperture gathers less light but with a smaller exit pupil of 3.25 mm, it also darkens the sky more than your usual 20×80 and thus should help somewhat if you’re observing in light polluted skies. The Oberwerk 20×65 ED Deluxe employs high-index BaK4 prisms to ensure maximum light transmission. The eyepieces are a five-element modified-Erfle design set in three groups yielding a very well corrected 3.2° of binocular sky. As you’d expect from Oberwerk, all optical surfaces are fully broadband multicoated to reduce glare and off-axis flaring. The eyepieces are adjusted individually avoiding the necessity of having a diopter adjustment. That’s perfectly acceptable for their main intended purpose, observing the night sky or distance viewing by day. And there’s plenty of eye relief at 18 mm, but eyeglass wearers will need to fold down the rubber cups to access the entire field. To take in that full view, a binoculars’ interpupillary distance (IPD) must be adjusted to match the distance between the observer’s eyes. In the case of the 20×65s, the IPD can accommodate a range between 2.2 and 2.9 inches (5.6 and 7.4 cm), a good range of adjustment. Optically, user reports are almost invariably excellent. Chromatic aberration is almost entirely absent and the instrument is very well corrected for astigmatism and barrel distortion, important optical attributes if you do most of your observing

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during the day. The Oberwerk 20×65 ED Deluxe serves up stunning views of the night sky and is well worth the modest price tag for such a high-quality instrument – $539.95. Check out the review in the September 2021 issue of Astronomy magazine by noted amateur astronomer and author Phil Harrington for more details. While we’re discussing Oberwerk, it pays to know that the company also offer even larger Astro-binoculars in their XL series, some with whopping 5-inch (127 mm) objectives, and all at reasonable prices.

Giant Astro-Binoculars from APM

APM’s flagship 150 mm 90 degree SD Apo. (Image Credit: APM)

Back here in Europe, APM (Astro-Physics and Mechanics) is a German-based company that specializes in producing high-quality binoculars and telescopes for astronomical and terrestrial use. Their range of large ED/Apo binoculars includes several models with different specifications and features, including either FK-61 or FCD100 low dispersion glass, fully broadband multicoated optics, quality highindex prism in a robust, waterproof housing. Although they come supplied with APM eyepieces the user can use any eyepiece of their choice. Good collimation is ensured at powers up to about 100× but with some tweaking magnifications of up to 200× can be coaxed from these large binoculars. Here are some examples: APM 100 mm 45 Degree SD Binoculars: These binoculars feature a 45-degree angled eyepiece design and a 100 mm objective lens diameter. They come with a choice of either 45-degree or 90-degree prism diagonals, and can be used for both astronomical and terrestrial viewing. The binoculars are relatively lightweight and can be mounted on a tripod. Most folk opt for 90 degree diagonals for stargazing and 45 degree prisms better suited to terrestrial viewing.

World Class Performance from Fujinon

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APM 120 mm 45 Degree SD Binoculars: These binoculars have similar specifications to the 100 mm model, but with a larger 120 mm objective lens diameter. They are designed for high-resolution astronomical observations, and are suitable for viewing deep-sky objects such as galaxies, nebulas, and star clusters. The binoculars are heavier than the 100 mm model and require a more robust mount. APM 152 mm 90 Degree ED APO Binoculars: These binoculars are the largest in APM‘s range, with a massive 152 mm objective lens diameter and a 90-degree angled eyepiece design. They are designed for serious astronomical observers who require the highest level of performance and image quality. The binoculars feature either FK-61 ED glass in the lower priced offering and FCD100 glass in their most expensive model, and are capable of delivering a bright, sharp, and color-accurate image. However, they are also extremely heavy and require a specialized mount and tripod. Product support for these high-quality astronomical binoculars is excellent. APM even wrote comprehensive collimation instructions for these instruments and are available as PDFs downloadable from their website. These are expensive instruments – the buyer will have to shell out as much as 10,000 Euro – for the biggest and the best of their line – but you do get what you pay for.

World Class Performance from Fujinon If you think the giant astronomy binoculars from Oberwerk or APM are the cat’s meow, then you should also take a long, hard look at Fujinon’s state-of-the art LB150 series of 6-inch aperture binoculars. Three models are offered at the time of writing: the 25×150 MT-SX, the 25×150 ED-SX and the 40×150 ED-SX. These state-of-the art instruments are what many would consider to be the nirvana of large aperture binoculars for astronomy. We’ll briefly take a look at just one of these; the 150 MT SX.  With its massive 150  mm objective lenses, these allow for excellent light-­ gathering ability and clear viewing even in low-light conditions. The 25× magnification is also very powerful, making it easy to see distant objects with great clarity. The binoculars are built to withstand the rigors of marine and nighttime environments, with waterproof and fog-proof construction that protects against moisture and temperature changes. The optics are fully multi-coated using the company’s highly advanced electron beam coating technology for the highest levels of light transmission in reducing glare, resulting in clear, tack-sharp images from edge to edge. Eye relief with this individual focus instrument is a reasonable 18.6 mm and seems likely to accommodate most eyeglass wearers while not being so great as to cause problems. The interpupillary distance adjusts from 56 to 72 mm and the field of view with the 25× eyepieces is 2.7 degrees. While the field of view isn’t outstanding for many optical configurations, it’s actually not bad for a 25×150 binocular! With a 6.0 mm exit pupil, you can be assured of relaxed comfortable views of the night sky. Close focus distance is nearly is about 17 m. The Fujinon 25×150 MT binoculars are also equipped with a range of features that make them easy to use and

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adjust. These include individual eyepiece focus, a tripod mount, and a built-in reticle for measuring distance and size. The binoculars come with a sturdy carrying case for transportation and storage. However, it is worth noting that these binoculars are quite heavy, weighing in at over 30 pounds, and are therefore best used with a very sturdy tripod or dedicated permanent mount. Additionally, they are quite expensive – you’re talking $6500 for the unmounted instrument alone – so may not be the best option for casual users or those on a budget. That completes our brief survey of the kinds of binoculars used for astronomical viewing. In the next chapter, we’ll survey the marine binocular market to see what’s what.

Chapter 9

Marine Binoculars

On the hot, sunny afternoon of August 8 2022, our family took a boat trip around Ramsey Island, off the Pembrokeshire coast, Wales. It was not my first boat trip, far from it, but it was my first-time carrying binoculars to spot birdlife, porpoises, dolphins and seals. I brought along my trusty Opticron SR.GA 8×32 Porros. Visibility was perfect that day, allowing me to enjoy wonderful views of the coastline beautifully illumined in late afternoon sunshine. But even on this relatively calm day, the sea could be quite choppy and the reflection of intense sunlight off the water made glare a real problem. Indeed, every time I turned my binoculars anywhere near the Sun, glare became a real issue, drowning out details of the cliffs above. And while I got my very first sighting of a number of new bird species that day, including Kittywakes, Razorbills and Choughs gliding on the summer thermals above the cliffs, it gradually dawned on me that a slightly lower power might have served me better. Normally 8× provided ample stability for me, but on the rolling seas, the same magnification proved a little too unstable. Our tour guide on that afternoon also carried binoculars and kindly offered the crew members to have a look through them. I couldn’t wait to compare and contrast the images through my own instrument and his. It was a bigger binocular than mine, another Porro prism design, covered with a rather worn-out black rubber armoring. The specifications were very interesting; 7×50. It didn’t recognize the make; it looked foreign, probably Russian. When I finally looked through them, I was alarmed to discover that they had rather poor optical quality. They weren’t anywhere near as sharp as my instrument and had quite a narrow field of view compared with the sumptuous 8.25 angular degree field offered up by my 8×32. Contrast was poor too. Still, the 7× magnification proved quite stable, significantly more in fact than my 8× glass, and after a while I convinced myself that this lower power glass was probably that little bit more useful than my 8× instrument. I was able to see details more stably at 7×, even though the views were not anywhere as good as my 8× Porro.

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_9

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The SR.GA 8×32 had good, thick rubber armoring, which afforded some protection against sea spray, but it was not waterproof, which presented some cause for concern. And though I was lucky to avoid any serious issues from the sea water, when I examined the binocular lenses upon arrival back at our holiday home, I could make out quite a bit of caked salt that had been deposited on both the ocular and objective lenses of the instrument. I immediately washed off the salt deposits as these could potentially degrade the delicate anti-reflection coatings on the lenses before finally giving them a thorough clean with lens cleaning fluid. What’s the moral of this story? Well, it taught me the challenges of glassing at sea. 7× was better than 8× and the larger exit pupil made engaging with the image that little bit easier. Waterproofing was an absolute must, especially if you’re using the instrument every day. Protection from glare was also very important – at sea you’re guaranteed to get a lot of it, even on an overcast day. I could also see that larger objectives would prove indispensable, especially when the light begins to fade. It made perfect sense to me, in retrospect, that a good, waterproof 7×50 with advanced coatings applied to the outer lenses to protect against the harsh saline spray and the intense UV irradiation might prove to be the ideal marine binocular. And as I began to do more research on this interesting topic, I was not surprised to learn that the tried and trusted 7×50 format was indeed the most common choice used by mariners the world over. Many binocular novices, regardless of the planned use for their instruments, start off by looking for the highest magnification available. Afterall, high powers get you closer to the action, right? The problem is that when you increase magnification, you also increase image shake due to unsteady hands. No matter how steady you think your hands are, you simply can’t avoid image shake when binoculars exceed more than 10×. Compounded with this, the vessel you’re floating on introduces its own shake. The result; a blurry picture, a churning stomach and maybe even headaches. Regardless of the type of vessel you find yourself on, movement will occur while underway, and the best way to make your viewing reasonably steady is to limit the binocular’s power to somewhere around 7×. Lower powers are, of course, more stable again, but at the expense of seeing details. The 50 mm objective is also highly recommended though not essential, as this relatively large aperture is ideal for gathering a decent amount of light, which facilitates viewing in less-than-ideal lighting conditions that many mariners find themselves facing on a daily basis, especially when entering and leaving port in the early or late hours of the day. Another advantage of the classic 7×50 binocular is that the combination of power and objective size produces a large exit pupil – the size of the image at the eyepiece. If your eye pupils are larger than the exit pupil, you will have the unfortunate experience of looking at a small image surrounded by darkness. When the exit pupils are larger, your eyes will see the image from edge to edge. The larger exit pupil allows you to view an image even when the motion of the vessel is changing the alignment of your eyes and the binoculars.

More Detailed Considerations

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More Detailed Considerations Most marine binoculars are of the Porro prism design that features the more traditional Z-shaped chassis. The objective lenses on the Porro prism binoculars are more widely spaced, and this provides a stronger 3D view of your target and the lower 7× providing excellent depth of field for the viewer. The roof prism binoculars are more streamlined and can be more compact laterally, while being generally longer than their Porro counterparts. This makes them ergonomically preferable for some users. BK7 prisms are not as good as BaK4 prisms and do not have as high a light-transmission. This is not to say that BK7 prisms are poor; in general, however, they are of lower quality than the BaK4. An easy way of identifying the prism of a binocular, if you’re unsure, is to hold them away from your face and look at the shape of the exit pupil: if it’s round it’s got BaK4, if it’s diamond-shaped, it’s probably BK7. This becomes more important if your eye is moving around a lot while surveying a marine scape, because you may hit the edge of the exit pupil and see a bit of vignetting. Of course, prisms from different manufacturers will have differences in quality and clarity, regardless of their configuration. It might be stating the obvious here that when you’re deciding on binoculars to be used in the marine environment, please make sure you buy a water-and fog-proof pair. Some binoculars designed for marine use will literally float if dropped in the water, and some may use polycarbonate chassis for enhanced corrosion resistance. Eye relief is also something to be considered if you’re a wearer of eyeglasses. Many binoculars offer diopter adjustments to allow eyeglass-free viewing, but if you want to leave your glasses on, make sure your chosen binoculars have collapsing eyecups, either rubberized or the twist-up variety, to accommodate eyeglasses. What about field of view considerations? The narrower the field of view, the more difficult it is to locate and track what you’re trying to view. The eye relief can also limit the size of the field you can image. If you wear eye glasses using a binocular with poor eye relief (say less than 12 mm) you simply won’t be able to access the entire field. Binoculars offering more generous eye relief (at least 16 mm) won’t give you this problem, so keep those numbers in mind when comparing binoculars. The wider the view, the easier tracking a target will be, but that may come at the expense of image sharpness, especially on the edges. Most 7×50 marine binoculars have fields of view in the 7° neighborhood. However, some pairs are relatively narrow at less than 6° and others are as wide as 8.3°, so, when shopping, keep an eye on this figure and keep the pros and cons in mind. Individual Focus versus Center Focus: This is a matter of preference. Most marine binoculars are of the individual focus variety; meaning the user focuses each eyepiece separately, negating the need to focus every time you use the instrument – once adjusted, everything past a certain distance will be in focus. Center focus is more traditional, where a focus knob changes the focus on both eyepieces. If you are sharing binoculars with your crew, center focus is advantageous and easier to use for most people. Individual focus is also good for observing in low light, where targets are often poorly seen and hard to make out. By adjusting them accurately

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during broad daylight, you can be assured that they will remain sharply focused when ambient light becomes scarce. Lens coatings exist to improve the performance of the lens by reducing reflections and increasing contrast. Lenses are multicoated, coated, or not coated. Prisms get the same treatment, this time to increase reflectivity, and roof binoculars may get treated with phase-correction coatings. The other goal of the coatings on both the lenses and prisms is to increase light transmission. On marine-specific binoculars, hydrophobic coatings serve to help bead and remove water spray on the optics. On smaller vessels, stuff gets knocked around while underway. Many marine binoculars feature a suit of armor made of rubber, or the tubes themselves are made from a rubber-coated polycarbonate, to help protect the binoculars. This rubber treatment also can help provide a surer grip for your hands or for whatever surface you place your binos on. Check to see if your marine binocular of choice has a bearing compass. Having one means there will be a superimposed image of a compass bearing in the image that you see. A bearing compass is a useful navigational aid for the boater and fisherman. An internal rangefinder reticle gives you the ability to calculate your distance from an object. You need to know the height of an object, and then measure the angle to its top using the rangefinder reticle. Remember that navigation charts often include heights of navigation markers that can be used as your reference height. This wouldn’t be much of a binocular buying guide if it failed to talk about weight. A heavy binocular would be considered to be over two pounds in weight. Some mariners find heavy binoculars to be easier to hold steady and better for viewing objects on a rocking boat, albeit for shorter periods. Many marine binoculars ship with floating straps, but you can also add one after purchase. If your optics decide to go swimming, a floating strap may be a great investment! And, since you purchased a waterproof pair of binoculars, rinse them off with fresh water and keep on going! It’s worth noting that there are a number of image stabilized binoculars on the market today. Using optical image stabilization technology that first appeared in camera lenses, they allow the boater to achieve a steady view at magnifications that are far more stable than a  traditional 7× marine binocular. Even though they are packed with electronics, some are waterproof but most are not. You will likely want to avoid pairs that are only “weatherproof” for marine use. One disadvantage is that they are battery powered. If you run out of juice, you will be left with a pair of binoculars that are far too powerful, and that may have an objective that is too small for comfortable and effective marine use. Manufacturers also have developed stabilized binoculars that integrate night vision technology into the package. Some allow day use and then nighttime viewing with the addition of Night Vision (NV) eyepieces.

Some Nicely Appointed Binoculars from West Marine

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Possible Alternatives 7×50 is the traditional marine binocular, due to its comfortable magnification power, very good light-gathering capabilities, and large exit pupil. In reality, any binocular can be used on the water regardless of size, features, or power. There are alternatives that you can explore as long as you know the limitations. The mainstream birding binocular is 8× and has an objective around 42 mm. The difference between 8× and 7× is not huge, but it can make a difference when out at sea. I have personally used 8×42 binoculars on board a large ferry boat across the English Channel in summer but I can tell you in no uncertain terms that using those same binoculars on a small sailboat in a seaway will be very challenging indeed. Smaller and lighter 7×35 or 7×42 binoculars might be an attractive option, especially on smaller craft when space is tight, or for smaller hands. However, the 35 mm objective will simply not let as much light in as a 50 mm pair, all other things being equal, and that can make a huge difference at night or around dawn and dusk. Now we’re ready to have a look at some of the more popular marine binoculars readily available on the market today.

Some Nicely Appointed Binoculars from West Marine West Marine, a company based in Southwest Harbor, Maine, USA, specializes in supplying a number of marine binocular models to suit most anyone’s budget. They have also brought out their branded version of sea-worthy instruments including the Coastal 200 7×50. This instrument has a durable polycarbonate chassis overlaid by a tough blue colored rubber armoring. The Coastal 200 has a nicely tuned central focuser, is filled with dry nitrogen to prevent fogging. Internal O-rings create a seal to ensure adequate protection from the encroach of seawater.

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West Marine’s Coastal 200 7×50. (Image Credit: West Marine)

They come with a certified IPX7 waterproof standard, so should hold up very well. They also feature multi-coated lenses for increased brightness in low-light conditions and BaK-4 prisms for sharp images. Light transmission efficiency is a very respectable 85% and delivers a well corrected 6.5-degree field of view. The eye relief on these units is very generous – 27.4 mm – so they can very comfortably be used with or without eyeglasses. Tipping the scales at just over a kilo, you can pick one up for a decent price of $219.99 with free shipping. West Marine also offer a more sophisticated binocular with a built-in rangefinder and illuminated compass in an otherwise similar chassis to the Coastal 200 7×50. Called the Coastal 400C 7×50, it’s significantly lighter than the 200 at 850 g and comes with a three-year no-fault warranty. But you’ll have to fork out nearly twice as much for the privilege of owning it.

A Rangefinding Marine Binocular from Bushnell

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A Rangefinding Marine Binocular from Bushnell

The Bushnell Marine 7×50. (Image Credit: Bushnell Sports Optics)

US-based sports optics company Bushnell sell a good quality 7×50 binocular especially designed for work at sea. Two models are available; one with a range finding reticle installed and another without. The range finding Mariner 7×50 is not only hermetically sealed and nitrogen charged, it also has a grippy rubber armoring that is resistant to salt water. Special UV protective coatings and an internally placed UV filter protect your eyes from the Sun’s most harmful rays. The fully multicoated Porro prism optics have roll-down eyecups, important for those who wear prescription eyeglasses or sunglasses. These binoculars are also tripod adaptable and have a 3-axis digital compass. The field of view is a decent 6.7 angular degrees. To estimate distance to marine targets you use the built-in reticle. In essence, the range finder is a reticle visible through the binoculars that allows you to calculate the distance to an object based on its height. The reticle is a vertical scale located above the compass display on the left side of the binoculars. Each mark on the vertical scale corresponds to a value of 5 MIL, with 1 MIL representing an angle that can determine an object one meter in height at a distance of 1000 meters. By sighting on an object and counting the number of MILs, you can determine its distance using a simple formula: (Objective Height (m)/Scale Reading)  ×  1000  m  =  Distance in Meters. Similarly, if you know the distance to an object, you can calculate its height using the formula: (Distance (m) × Scale Reading)/1000 = Object Height in Meters. The basic Bushnell Marine 7×50 retails for $164.99, while with rangefinder and compass costs $209.99.

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A Sea-Hardy Binocular from Oberwerk Good Marine binoculars needn’t cost the earth. For example, US-based binocular company, Oberwerk, sell a very well armored waterproof 8×40 Porro prism model offering a whopping 8.4-degree field of view – one of the widest in the industry. The Marine 8×40 is built like a proverbial tank, weighing in at just under 1 kilogram. It’s thoroughly modern with twist up eyecups offering 10  mm of useable eye relief, fully broadband multicoated optics and high-index BaK4 prisms. The objectives are nicely recessed to cut down on glare and afford good protection against the elements. The 8× is useful for bringing objects at sea that little bit closer than 7× models and the spacious field of view greatly helps in tracking fast moving targets. The guys at Space.com gave it a glowing review as “Editor’s Choice” but concentrated more on its astronomical prowess more than anything else. Optically, this is an impressive binocular with a nice big sweet spot but with a field this large, there is some peripheral softness to the image but in practice, there is ample field of view to impress the vast majority of users.. Owners report no issues with glare or internal reflections – a particularly important result if you’re glassing out at sea. With a retail price of only $149.95, these are a terrific bargain in today’s market and the company’s excellent customer service will quickly solve any issues you might have with your purchase.

The Oberwerk Marine 8×40. (Image Credit: Oberwerk)

State-of-the Art Marine Optics from Steiner

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A Sea Friendly Glass from Helios

The Helios Oceanmaster-RC 7×50. (Image Credit: Optical Vision Limited)

Helios, a well-established optics company now owned by the UK-based Optical Vision Limited, has also brought to market a nicely featured marine binocular. Called the Oceanmaster-RC 7× 50, it’s covered in a thick blue and black armoring, and equipped with high quality BaK4 prisms, o-ring sealed and filled with dry nitrogen gas to ensure it’s fully seaworthy. The Helios Oceanmaster also comes with a built-in compass with illuminator, and a rangefinder with reticle for navigational purposes. It’s on the heavy side though, tipping the scales at 1140 g. Optically, the images are bright, clean and sharp across most of its 6.6-degree field. You can pick one of these up for £170 (UK).

State-of-the Art Marine Optics from Steiner Steiner has long been recognized as a world leader in the design of marine and military binoculars, with over 75 years of market experience. One of their best-selling lines of marine binoculars is their newly redesigned Navigator series, Steiner’s entry level line of marine hardy instruments. They offer four models in this series consisting of a 7×50 and smaller 7×30 model as well as the same models with a built-in compass (denoted by a c after the name) The highly ergonomic open-bridge chassis is made from makrolon, a tough, polycarbonate material designed to absorb shocks as great as 11G and can be used in temperatures ranging from −20°  C to+70° C. One might legitimately ask why a top temperature of 70° C is quoted, but anyone working in a marine environment will tell you that exposure to intense sunlight for hours on end will quickly render less well-built binoculars useless. The supplied binocular strap clicks into a slot on either side of the eyepiece lenses. By

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pressing a button on the top of the chassis, the straps can be released. This is arguably one of the most sophisticated straps ever designed; one that other manufacturers are sure to adopt in the future.

The Steiner Navigator Pro 7×50C. (Image Credit: Steiner)

The Steiner autofocus system ensures that once you’ve adjusted the eyepieces to give sharp focus in both eyes, everything beyond 20 yards remains in crystal clear focus in all weathers. The field of view is 7.06 degrees in the 7×50 models while the 7×30s deliver a wider, 8-degree true field. All the Navigator models are waterproof to a depth of 5 meters. Steiner was the first company to add an integrated compass into their binoculars so you can purchase the Navigator with (denoted by C) or without a compass. The compass enjoys a special Steiner patent with a built in LED light and window for easy reading. The focusing mechanism is not central, just like many other marine binoculars but instead the eyepieces must be adjusted individually. Steiner claim that this ensures that a higher level of waterproofing can be achieved without having a more conventional central focus mechanism as well as the certainty that they will remain sharply focused in low light settings often encountered at sea. Like nearly all Porro prism binocular, the Steiner Pro series come with soft rubber eyecups that can be folded down for use with eyeglasses. Eye relief on the Navigator Pro 7×50 is a generous 20 mm. Optically, the Navigators are quite excellent. The smaller 7×30 models have the advantage of lower carrying weight (500 g) and are considerably smaller than the 7×50. The downside of the 7×30 model is a smaller exit pupil and lower overall light gathering power. In terms of value for money, the Navigator series are very hard to beat; built to last and made in Germany, with a 10 year no fault warranty. And even after the warranty runs out, Steiner will repair or replace parts at a very reasonable cost. The 7×30 models sell for about $400, while the larger 50 mm models cost $690. For those who must have the absolute best marine optics, Steiner offer their highly advanced Commander series of binoculars packed full of state-of-the-art technology. These military-grade, Porro binoculars are the choice for anyone who makes their living on the water. These binoculars are also for those who live abroad or spend weeks on the water – yacht owners, blue water sailors and racers – who need the finest in marine optics. The Commander Series has every feature and all the

Breaking the Mold: Hawke Endurance ED Marine 7×32

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performance serious mariners demand, backed by Steiner’s unrivaled reputation for total reliability on land and sea. They promise to deliver world class image clarity, sharp edge-to-edge definition and contrast, and high light transmission for navigating in low light or fog. The Commander 7×50 is a much bulkier binocular than the 7×50 Navigator and offers a wider field of view to boot −8.4 angular degrees in fact! The instrument comes with a dual valve system so that fresh dry nitrogen gas can be injected into the instrument quickly and precisely. Winged rubber eyecups ensure the minimization of glare from peripheral light – a common problem on a bright day at sea. The optics have also been upgraded from the Navigator series, with state-of-the-art exterior nano coatings to prevent against oil, salt water and dust. The Steiner Commander binoculars comes in the standard form without a compass or you can choose the Commander C 7×50 which features a built-in digital compass that allows the user to know their precise location on earth. A patented memory diopter system allows you to store and easily relocate your personal diopter setting. The Commander binoculars from Steiner also come in with a floating yellow neck strap with a 3 M reflective trim, allowing it to be easily located should the binocular fall into difficulty. Unlike the Navigator series, Steiner do not offer a smaller 7×30 instrument in the Commander series. As one might expect for all of this technology, the Steiner Commanders retail at $1470 for the basic instrument and $1795 for the built-in compass model.

Breaking the Mold: Hawke Endurance ED Marine 7×32

Hawke Endurance ED Marine 7×32. (Image Credit: Hawke Sports Optics)

While heavily-armored Porro prism binoculars have dominated the Marine binocular market for quite some time now, the British-founded company, Hawke, has moved in a completely different direction in launching their new line of marine hardy roof prism binoculars. Offered in two formats; 7×32 and 7×50, these feature a completely waterproof (IP67-rated) and fog proof optical system that also enjoy a number of features that arguably make them even more versatile than any other marine

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binocular on the market. Tests have actually been conducted on its water proofing too and report no problems with water infiltration even after 30  min of immersion in depths from 15 cm to 1 meter. Taking a closer look at the 7×32 model, the Hawke Endurance ED Marine tips the scales at only 545  g. The polycarbonate chassis is covered with a thick blue colored rubber armoring offering exceptional grip. The eye cups are of the traditional twist-up variety offering a number of intermediate positions to enable those who wear glasses to fully engage with the field of view. Eye relief is a very decent 17 mm. The metal focus wheel turns through just over two full revolutions from closest focus to infinity. And speaking of close focus, users report a value of just 1.3 meters; an exceptional result for an instrument not especially designed for such purposes. The objectives feature ED glass elements to reduce color fringing and the field of view of the 7×32 is an awesome 8.3 angular degrees. Users report excellent central sharpness and quite good edge-of-field performance thanks to BaK4 silver coated Schmidt-Pechan roof prisms. Unlike more traditional Porro prism marine binoculars, the Hawke Endurance ED Marine have enough eye relief to allow you to view through them while wearing sunglasses. In addition, the standard rubber fold down eyecups found on other marine binoculars are prone to splintering under the harsh environments encountered at sea, so the rubber-over-metal eye cups on these new Hawke models should hold up that little bit better. One of the most endearing things about the Hawke Endurance ED Marine binoculars is their versatility. The 7×32 can be used profitably for short-range birding, star gazing and hiking in the mountains. The excellent close focus will allow you to image targets at close quarters, such as Dragonflies and even the curious bird that may serendipitously land on your boat. All said, when you factor in their low retail price ($250 for the 7×32 model and $370 for the larger 7×50), you can see why they are enjoying great popularity among those who enjoy life at sea.

A Sea-Worthy Binocular from Fujinon

The Fujinon WP-XL Mariner 7×50. (Image Credit: Fujinon)

A Sea-Worthy Binocular from Fujinon

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For many binocular enthusiasts, and especially those who love classic Porro prism designs, the Fujinon binoculars tick all the boxes. Though the company’s 7×50 models are often specialized for marine use, they are also enjoyed by birdwatchers, hunters and general nature lovers because of the uncompromising optical and ergonomic features they pack into their products. Fujinon’s entry-level model, the WP-XL Mariner 7×50, features a fully multicoated optical system, a tough polycarbonate chassis, and a very well corrected 7.5-degree angle of view. Like many other 7×50s, the WP-XL Mariner possesses individual focus eyepieces with a comfortable 18 mm of eye relief. You’ll also note its much lower weight over the other models previously discussed, tipping the scales at just 820 g! Indeed, when the carrying strap is attached, the WP-XL 7×50 has an overall density less than water, allowing it to float! How cool is that! Don’t expect these to compare well with their more sophisticated instruments though. The WP-XL Mariner is manufactured in China to lower production costs. They are quite durable with some users getting 15 years of continuous use out of them. And the good news is that one can acquire these for about $200 in today’s market. That completes our brief survey of Marne binoculars. In the next chapter, we’ll explore the wonderful world of image stabilized binoculars that has taken the sports optics industry as well as the amateur astronomy community by storm.

Chapter 10

Image Stabilized Binoculars

Image stabilized binoculars are instruments that use advanced technology to reduce the effects of shaky hands and other movements, providing a stable and clear image. They are becoming increasingly popular among outdoor enthusiasts, nature watchers, amateur astronomers bird watchers, hunters, and other professionals who require a steady view of distant objects. The technology used in image stabilized binoculars is based on gyroscopes and sensors that detect and compensate for this undesirable movement. The most common source is hand tremors, which can occur at frequencies ranging from 3 to 10 Hz. At higher frequencies, the jitters may appear more like a blur rather than individual shakes. Higher magnifications can exacerbate any hand tremors, and small movements can cause the image to appear jittery. In addition, windy conditions make the image shake with much higher frequencies (typically 20–30 Hz), as can hot air rising from the ground on warm summer afternoons. Atmospheric turbulence or heat waves can also distort the image and cause it to appear shaky. When a person holds a binocular, the slightest hand movements can cause it to shake or jitter. This can be more pronounced when using a lighter binocular because it has less mass and therefore less inertia. This means that small movements, such as breathing or the beating of the heart, can cause the binocular to shake more. A heavier binocular, on the other hand, will be less sensitive to these small vibrations. This is because it has more mass and therefore more inertia. The additional weight also makes it easier to hold the binocular steady because it is less prone to being moved by hand tremors or slight movements. That being said, heavier binoculars induce muscular fatigue faster than lighter instruments, so there must exist an optimum binocular mass that can minimize hand jitters and muscular fatigue. Some sources I’ve read suggest this is in the region of 800 g but will, in all likelihood, exhibit considerable interindividual variation. Image stabilized binoculars employ sensors to determine the direction and magnitude of movement, and then adjust the internal optics to provide a stable image. Some image stabilized binoculars also have a mode that allows users to choose the © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_10

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degree of stabilization, depending on the level of movement or shaking. One of the main benefits of image stabilized binoculars is that they allow users to view distant objects in more detail and clarity than traditional binoculars. This is particularly important for birdwatchers and nature enthusiasts who need to observe animals in their natural habitat, and hunters who need to see their prey clearly and accurately. Image stabilized binoculars also make it easier to follow moving objects, such as birds in flight, as the image remains stable even when the observer is moving. Another benefit of image stabilized binoculars is that they reduce eye strain and fatigue. Traditional binoculars require the user to maintain a steady hand and hold the binoculars still for extended periods, which can be tiring and uncomfortable. Image stabilized binoculars eliminate this problem, allowing users to view objects for longer periods without experiencing discomfort. Despite their many benefits, image stabilized binoculars have some drawbacks. They tend to be larger and heavier than traditional binoculars, which can make them more difficult to carry and use for extended periods. They are also more expensive than traditional binoculars with similar optical quality, which may make them less accessible to casual users. They certainly don’t appeal to all binocular enthusiasts. This author would count himself in that camp. Somehow, the images seem somewhat contrived to me and are not as ‘real’ as the views through a regular binocular. In addition, these instruments are power-hungry requiring regular installment of new batteries. If you glass regularly, this additional cost adds up, so that, in a real sense, you go on paying for your IS binocular over the years. As a person who appreciates old-school, stand-alone gear with no electronic gizmos, looking through image stabilized binoculars feels like you’re looking through a camcorder. I’m fortunate enough to live in a small, rural village, where I can get to know many of my neighbors and learn about their interests. For example, just a stone’s throw away from my home lives a young man who works for the RSPB, and who routinely employs binoculars and a high-end spotting scope. Further up the village, I know a keen deer hunter who’s allowed me to test drive his very impressive Swarovski EL Range 10×42 on a number of occasions. And not far from him lives a retired psychiatrist who enjoys using image stabilized binoculars. One day, when I was out for my daily stroll, I met up with him as he walked his dog, and asked if I could borrow one of his Canon IS binoculars for testing. He agreed and offered me the choice of a 10×30 or a smaller 8×25. I chose the larger 10×30 model, as I wanted to test the image stabilizing technology at the higher power of 10×. What follows is a brief review of how it performed, based on a few days of use.

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A First-Generation Canon IS 10×30

The Canon IS 10×30 is an earlier model and is about 8 years old as of 2022. It has now been replaced with the Canon IS II 10×30. I was quite taken aback by the size of this instrument. Weighing in at 660 g (without its strap) it’s bulkier in real life than I had imagined it would be. I found the handling of this binocular to be quite difficult and awkward. It was hard to find a comfortable position in my medium sized hands. The objective lenses are well recessed – a good thing as the unit is not waterproof or dustproof. They do have rather nice, dull greenish antireflection coatings applied to the objective lenses which do not show much signs of degrading over the years. The ocular lenses also show nicely applied antireflection coatings but the eye cups are old-school soft rubber – you know the kind that fold down for use with eye glasses. The focus wheel is on the small side and I found the turning to be very smooth but somewhat stiff. It takes a bit of getting used to compared with my regular compact instruments which are much faster and easy to turn in comparison. Moving from close to far away focus takes quite a while to get there, so maybe not ideal as a birding binocular. The diopter setting is conventional. Located under the right ocular; it is very stiff and hard to rotate – just what you want if you don’t have a built-in locking mechanism. My first impressions of the Canon IS 10×30’s optics were very good. The 6-degree field is very sharp, nearly all the way to the edge of the field, thanks to built-in field flattening lenses. Contrast is good, although I did detect some weak

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internal reflections when I pointed it at a bright waning gibbous Moon and some streetlights at night. I experienced no blackouts with this model. The view is very comfortable and quite immersive, with a beautifully defined field stop which I always like to see. The eye relief proved perfect for my needs. Glare suppression is also good. By pressing the small button just ahead of the focus wheel, the gyroscopes are activated, and the magic begins. The small shaking movements in your hands are cancelled out and even more details pop into view. It’s quite amazing! I compared the views of the Canon IS 10×30 to a GPO Passion 10×32 ED in un-­ stabilized mode, which has the same size field (6-degrees). Going back and forth between the images for a few minutes revealed the latter to be the superior optic. Chromatic aberration could be clearly seen in the Canon on high contrast targets against a grey, overcast December sky. The GPO displayed virtually none in comparison. Furthermore, the GPO displayed noticeably better contrast and a significantly brighter image to boot. That said, once the IS button was activated, the Canon showed more than the GPO, with very fine details jumping out of the image! The stabilized image clearly resolved finer details on all the targets I tried it on. I would say that the effect was immediately noticeable and dramatic. To verify that the increase in resolution was attributed to the stabilization, I placed the GPO 10×32 on a tripod and compared the images; sure enough, I could see the same additional details- and a bit more besides – on the same targets, only that they were brighter, better contrasted, and presenting with a little more color ‘pop’. Turning to the Pleaides star cluster well placed in the evening winter sky, I compared the non-stabilized view to the IS-activated view. Just pressing the button showed faint stars popping into view which were quite invisible in the non-­stabilized image. Consulting some older literature on the effects of image stabilization, I read that some observers report an enhancement as much as one stellar magnitude. I wasn’t able to confirm this figure but I don’t doubt the claim. Again, very impressive! I would say that the stabilization makes the small 10×30 optics behave more like a significantly larger un-stabilized instrument, like a 10×40 or some such. Looking at a last quarter Moon also showed me more details than the 10×32 ED when the IS button on the Canon was engaged. I could resolve finer crater detail, although it did show up more chromatic aberration than the GPO control binocular. So what did I think of the Canon IS 10×30? In a word, Groovy! Sure, it’s not got the best ergonomics and is big and bulky for its aperture, but there is no doubting the technology behind the instrument! If you can live with its less-than-ideal handling and lack of weather proofing, you most certainly will be very impressed with it. The optics are very good but maybe not excellent, but when that stabilization button is activated, it leaves even top-rated 32 mm models in the dust. Stabilized images just show you more details! Overall, my experience with the older Canon IS 10×30 was very favorable. Indeed, it had gotten me curious about two smaller models that were recently released by Canon; the Canon IS 8×20 and 10×20, both of which are significantly smaller and lighter than the 10×30. The small exit pupils on these sub 500 g models are no deterrent for me either, as I’ve come to appreciate the coupling of good optics with the best part of the human eye. Stars should be beautiful pinpoints in these models!

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Curiosity got the better of me, so I decided to buy and test the smaller 8×20 IS, the subject of this next section. The Canon 8×20 IS arrived neatly boxed away inside its soft carry case, together with a comprehensive user manual, lithium ion battery, and warranty card. Weighing in at 420 g without the battery, the binocular has a tough, grey colored plastic chassis which I immediately found much easier to handle than the larger 10×30 IS, which weighs about 50% more in comparison. Like the older generation models, the new Canon 8×20 IS has soft rubber eye cups that can be folded down for use with spectacles. Turning next to the objectives, I was quite surprised but very happy to see that the 20 mm objectives on the Canon were very deeply recessed; far more deeply in fact than any other binocular I’ve thus far encountered. Doubtless, this helps quite a lot in keeping stray light, dust and rain at bay; a good thing surely, as these units are not waterproof.

Two 8×20 binoculars: the Leica Ultravid 8×20 (left) and the Canon IS 8×20 (right)

The focus wheel on the Canon IS 8×20 appears to be made of metal. It has very good grip and is large enough to access and maneuver even while wearing thick winter gloves. The diopter compensation is achieved in the traditional way, by rotating the base of the right eye cup until you achieve your desired setting. The single CR123A lithium-ion battery is easily installed in a pull-out compartment located under the focus wheel. The image stabilization is achieved by pressing a small button offset onto the right barrel of the binocular, causing a small green LED to light up while it’s being activated. The instruction manual states that the

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battery has a lifetime of about 12 h at room temperature but is reduced to just 8 h at −10° C. During my tests I never encountered any problems using the image stabilization function, which involved a few hours of testing at temperatures ranging from PLUS_SPI 20° C to −2° C. The objective lenses on both the ocular and objectives have very nice and evenly applied anti-reflection coatings. The objective coatings have a pale, greenish tint while those on the eyepieces appeared magenta in daylight. In comparison with my experiences with the older generation Canon IS 10×30, the smaller 8×20 model was much easier to use in my medium sized hands. For example, it was considerably easier to hold it with two hands, and accessing the off-­ center stabilization button did not present any problems. The large, centrally placed focus wheel turns very smoothly, with excellent inertia and with no play while rotating clockwise or anti-clockwise. The rather old-school, flexi-rubber eyecups proved reasonably comfortable when they were pressed against my eyes. When I folded them down to test the eye relief for spectacle wearers however, I found it difficult to image the entire field of view using my varifocals. I think this is an area that Canon can improve on in the future. Playing around with the Canon IS 8×20 in my hands, and comparing it to a conventional 8×20 pocket binocular, I felt the latter was much easier to achieve a stable, comfortable grip with. So, while the newer 8×20 IS units are a big improvement over say a larger 10×30 IS, they are still nowhere near the comfort levels I experience using a conventional, dual-hinge 8×20 glass. I was quite impressed with the optical quality of the older generation Canon IS 10×30 but my tests on the newer IS 8×20 showed it to be a good deal better again. Conducting a bright light torch test showed no annoying internal reflections, diffraction spikes or diffused light. Indeed, it was a good step up from the results I achieved with the older, Canon IS 10×30 in this regard. No doubt, this is largely attributed to the improved ‘Super Spectra’ coatings applied to its optical elements. Looking through the Canon IS 8×20 during dull, overcast winter weather, I was immediately impressed with the excellent sharpness, contrast and brightness of the image from edge to center. Like the older models, these smaller Canon IS binoculars have built-in field flattening lenses which reduces field curvature and other off axis aberrations when viewing a target away from the center of the field. Indeed, in low light tests I conducted alongside my excellent Leica 8×20 BR Ultravid, I judged the Canon IS 8×20 to be equally bright, but just falling short of the sharpness of the Leica. Glare suppression, however, was noticeably better in the Canon though. This is probably attributed to the very deeply recessed objective lenses on the Canon IS binocular in contrast to the Leica, the objectives of which are not at all recessed (maximizing its compactness) and so are at the mercy of intrusions of stray light. One aspect of the view was less engaging with the Canon IS 8×20 over the hand-­held Leica Ultravid 8×20 though. Despite having a slightly larger field of view (6.6 vs 6.5 angular degrees), I felt the field was significantly more immersive in the Leica compared with the Canon 8×20. It almost felt as if I were watching a scene on a movie screen in the latter compared with the feeling of being much more ‘in the image’ using the Leica.

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Chromatic aberration was an absolute non-issue in the Canon IS 8×20, unlike the larger and older Canon IS 10×30. Indeed, it was fully the equal of the Leica Ultravid 8×20, with only the extreme edges of the field showing up the merest traces of secondary spectrum whilst glassing high contrast daylight targets. Close focus was found to be very good in the Canon IS 8×20 too. I measured it at just over 2 meters, in accordance with the stated numbers issued by Canon. Still, the Leica Ultravid 8×20 BR was noticeably better at 1.8 meters. I perceived slightly better stereopsis in the Canon compared with the Leica glass. This was largely to be expected, as the objectives of the Canon are slightly further apart and so creating better depth perception in comparison to their roof prism counterparts. All in all, I judged the Canon IS 8×20 to have excellent optics, as good or better in many respects to the best roof prism instruments models available today. The real magic of these binoculars takes place when you press the image stabilization button. Like the larger 10×30 IS I tested prior to this, the smaller Canon 8×20 IS works brilliantly. Aim at your target, focus as sharply as you can and press the IS button. You can immediately see finer detail that’s quite invisible in the non-­ stabilized views. The stabilization function works in two modes: sporadic and continuous. Most of the time, I used the button to stabilize the image for a few seconds before disengaging. But the IS function can also be used continuously for up to 5 min. I got on less well with the latter mode, as I felt a bit queasy moving the binocular from one target to the other and watching the images ‘swim’ into stabilized mode. In another test, I compared the stabilized views on the Canon 8×20 IS to a tripodmounted Leica Utravid 8×20. Carefully going back and forth between the instruments, I discerned slightly more details in the tripod-stabilized Leica than the Canon 8×20 IS. This is in keeping with my results with the older generation 10×30 IS. The tripod-stabilized view offers a little more in the way of resolution at the cost of losing portability. In yet another test, I aimed the Canon IS 8×20 on the Pleaides star cluster high in the winter sky, comparing the non-stabilized view with the images served up when the IS function was engaged. The results were quite dramatic; many fainter stars popped into view when the IS button was engaged. Very impressive! The Canon 8×20 IS serves up very impressive views, even when the image stabilization function is dis-engaged. These newer models have noticeably improved optics over their older counterparts, especially in terms of brightness and contrast, and in the control of stray light. Indeed, optically, they are very close to the quality served up by the world’s best pocket binoculars. Having said that, while I fully acknowledge that the smaller weight of these new Canon IS binoculars is a big step in the right direction in terms of ergonomic handling, they still fall quite a bit short in terms of how good they feel in my hands compared with the little Leica Ultravid. Indeed, I think the engineers at Canon could make some significant improvements in the shape of the chassis to allow a better grip in the hand. What’s more, their lack of waterproofing will put others off, especially if they intend to use them for long periods in the field, when the weather can change without warning. So, all in all, a terrific product, but still some room for improvement.

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Is there a collective noun for Canon IS Binoculars? (Image Credit: Gary Murphy)

So, what about the larger Canon IS models. How do they perform in the scheme of things. To help answer this I canvassed the opinion of Gary Murphy, a keen amateur astronomer and birder who owns and uses several of the larger Canon IS models. Here’s what he had to say: “The IS binoculars are each unique in their own right, except for the commonality of the ×15s and ×18. The ×15 has a bit wider field of view and with the lower magnification, it’s a tiny bit easier on the IS electronics. The ×18 has better reach, but benefits from a bit of bracing when held; but it can still be used okay when standing. Both have large rubber eyecups that work fine for me, but many dislike them. The most noticeable point of difference is that the ×15s are right on my maximum overfocus limit without glasses, whereas the ×18s have a bit of an additional margin. They are both fairly heavy, but most ×15/×18 ×50s are. These bigger magnifications are probably the most noticeable when the magic button is pressed. Hand holding this magnification is impossible and most noticeable when pointed skyward, until the button is pressed and, ‘as if by magic’ a steady image appears. Perhaps not as good as a tripod or parallelogram mount, but far more portable and better suited for quick viewing sessions. The small, light 12×36 III is probably the most used so far. Yet, it is not at the 10×42L in terms of optical quality. No real reason for this except perhaps that the 10×42L is the more recent purchase. The ×10 is very good optically. The major downside is size and weight. Ergonomically, I find all these fine, but many don’t. The eyecups of the ×12 are small rubber, whereas the ×10s are large click up (modern) type. Again, some have problems with the eyecups, but I don’t. Both these sizes also work without glasses for me, so eye relief is so far not a limitation either. I don’t really have a preference for any one of these. Like most binoculars, it seems to be more about which I feel like using on the day. The ×15 and ×18s won’t be together, as I’ll bring one pair to Spain and the other will stay at our home in Northern Ireland. One thing for me is that most of my use cases for IS binoculars is for longer distance viewing. I rarely use IS for close distance. My ×6.5–×8s porro/ roofs are usually used for this. In the mountains, I use small 8×25s, due to weight and size. But maybe in the future I’ll get a 8×20 IS, but I doubt it.”

Image Stabilization from Fujinon

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Image Stabilization from Fujinon

Fujinon’s 14×40 TSX1440 Techno-Stabi Image-Stabilized Binocular. (Image Credit: Fujinon)

Recently, the Japanese optics giant Fujinon has also entered the Image Stabilization binocular market with their range of Techno_Stabi TS binoculars. To date, three models are offered: a 12×28, 16×28 and a 14×40. The 28 mm aperture models replace an older 32 mm model. These binoculars feature a robust image stabilization system ideal for vibration-free observation from boats, automobiles and other vantage points subject to vibration. The compact 12×28 binocular is lightweight and ideal for nature, sports, concerts, or astronomical use where the user may want to view the event at a higher magnification and without a tripod. The optics are fully multi-coated, and the prisms are phase corrected for bright, high-contrast images. With a vibration correction range of PLUS_SPI /−3 degrees, they can be effectively used in even the wobbliest of situations, such as on a boat on choppy water. The body structure is designed to protect the optics and prevent dirt or dust from adhering to the optical elements. The precise center focus wheel makes it possible to bring details into sharp focus with just the movement of the finger. Twist-up eyecups are easy to use and offer comfort for the user. The TS 12×28 is made of fiberglass-­reinforced, high durability plastic, which helps keep the carrying weight down. Indeed, the 12×28 tips the scale at less than 500 g. The field of view is understandably narrow in the 12×28; just 4.2 degrees. Rather bizarrely, the 16×28 model has only a slightly smaller field of view of 4 angular degrees. Eye relief is a very generous 17.5 mm on the 12×28 though, so should be ample enough even for eyeglass wearers. The 16×28 is a bit tighter at 16 mm. The small aperture and exit pupils delivered by these 12 and 16×28 models (2.3 mm and 1.75 mm, respectively), means they are ideally suited to good lighting conditions. Retailing for $600 and $650 for the 12 and 16× models respectively, they represent good value in today’s market. The larger 14×40 Fujinon Techni-Stabi X is packed full of even higher tech features than the smaller 28 mm models. For one thing it offers the best stabilization on the market with an impressive PLUS_SPI /−6 degrees. It’s also fully waterproof,

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making it suitable for all-weather use. With a 2.66 mm exit pupil and 13 mm eye relief, some users report increased difficulty centering their eyes to avoid blackouts. As you’d expect, this larger Fujinon model isn’t exactly light at 1.3 kilos. Expect to pay $1100 for the privilege of owning it.

Three Compact IS Binoculars from Opticron The UK-based company, Opticron, has also introduced their own line of small, compact IS binoculars. The Imagic IS range comprises three models, a 10×30, 12×30 and 14×30. Suitable for almost all types of daytime wildlife and nature observation, surveying and lunar astronomy, the Imagic IS binoculars gives you the freedom to observe ultra-stable views of your surroundings.

The Opticron Imagic IS 12×30. (Image Credit: Opticron)

Let’s take a closer look at the 10×30 model. The optics are fully multicoated, delivering sharp and bright images. The field of view is decently large – 5.2 angular degrees – and it exhibits dual axis (X-Y) stabilization over PLUS_SPI /−3 degrees. Weighing a little over half a kilo, the Opticron Imagic IS 10×30 has a 3 mm exit pupil, giving decently bright images even in compromised lighting conditions, such as under a forest canopy, on an overcast day, or when the light begins to fade in the evening. The twist-up eyecups have decent eye relief at 15 mm and the unit is covered with a nicely textured black rubber for good gripping even in wet conditions. The unit is not waterproof though, but merely splashproof (IPX4 rating). Close focus on the 10×30 Imagic IS is just under 3 m. And if you happen to forget to leave the power on, it automatically switches off after 5 min. These little Opticron IS binoculars really come into their own watching small birds at a distance in windy conditions, where holding a regular binocular can prove

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difficult. The higher magnification models (12× and 14×) give you extra reach of course, but at the expense of a smaller exit pupil and thus dimmer images. You need to decide the best model for you. The good news though is that these excellent, compact IS binoculars can be had for a very reasonable price of just over $500. All the Opticron Imagic IS binoculars come with a 10-year warranty and are supplied with a soft vinyl case with rain guard, a neoprene strap and a pair of AAA 1.5 V batteries.

High-Powered Image Stabilization from Bresser

Bresser 16×42 Stabilizer OiS. (Image Credit: Bresser Sports Optics)

German-based sports optics company, Bresser, market their own image stabilized binoculars in the form of the 16×42 Stabilizer OiS. High quality optics are standard with this mode, including BaK4 prisms, fully multicoated optics, and long eye relief twist-up eyecups. A two-axis gimbal ensures good optical stabilization up to 2 degrees of image shift. The field of view (3.8 degrees) is a bit narrower than other models with similar magnification but close focus is a very decent 4 m. Though not waterproof, it is rated as IPX4 which should be ‘spashproof.’ The Bresser 16×42 is powered by a single AA battery for up to 30 h of use. It’s quite lightweight to boot at 644 g. Bresser offer their extended 10 year warranty with this product and retails for abut $1000.

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Could This Be the Cutest IS Binocular on the Market? Nikon has also entered the IS binocular market by developing what could arguably be the most elegant or cutest IS binocular yet developed. Called the Nikon Stabilized 10×25, it features fully multicoated optics, phase corrected Schmidt Pechan roof prisms, a decent 5.6 degree true field of view and 14 mm eye relief. Uniquely, these Nikon high tech binoculars fold on two hinges making them portable in an average pocket. When stored in this way, they are only 10 cm long, 7 cm wide and 6.5 cm high! A single CR2 battery gives you about 3.5 h of continuous use at 20C but the specs say that it can be operated at temperatures between −10° C and PLUS_SPI 50° C, so should work in most conditions binocular enthusiasts are likely to find themselves in. The Nikon Stabilized 10×25 tips the scales at just 430  g, making them one of the lightest image stabilized binoculars currently on the market.

Nikon Stabilized 10×25. (Image Credit: Nikon Sports Optics)

Users almost universally report great results, with sharp, high-contrast optics, good contrast and color rendering. Nikon state that they reduce shaking by as much as 80%, which will unquestionably allow the user to discern details quite invisible in a non-stabilized 10×25. Chromatic aberration is reportedly very low but, in my experience, this is more a result of the small aperture than anything else. Small lenses collect less light than larger models and that includes chromatic aberration. If you forget to turn the IS function off, never fear, it will automatically turn off after 10 min saving valuable battery time. One online critic stated that since his birding excursions last more than 3.5 h in the field, he would be forced to buy a new battery every time he went out! He’s got a point I suppose, as CR2 batteries cost about $1 at the current time of writing. Others have noted that although the Nikon Stabilized 10×25 has nicely designed twist-up eyecups, the rather short 14 mm eye relief is going to be tight for eye glass wearers. Others are put off by the small exit pupil (2.5 mm), making it of limited use in compromised lighting conditions.

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So why are they not more popular with birders? I think they’d work fine in good lighting conditions, where much birding takes place, but the rather small field of view of 5.6 degrees might make them less versatile than full-size instruments with their wider fields (6–6.5 degrees for 10× instruments and 7–8.5 degrees for 8× instruments). The only way to know for sure if they’re for you is to try before you buy. This is where Part I of the book ends. In Part II, I’ll be discussing some of the more well-known binocular companies as well as looking at some classic binoculars from yesteryear. This part will also take a closer look at testing binocular optics as well as exploring some of the accessories commonly used by binocular enthusiasts.

Part II

Binocular Companies, Classic Instruments, Accessories and More

Chapter 11

Leica Binoculars

The Leica Noctivid 8×42. (Image Credit: Sam Shepherd)

Leica binoculars are among the most highly respected and sought-after binoculars in the world. The brand has a long and storied history dating back to the late nineteenth century, and the company has become synonymous with quality, precision optics. The Leica brand was founded in 1914 by Ernst Leitz, who had been working in the optics industry since the late 1800s. Leitz was already well-known for producing high-quality microscopes, and he saw an opportunity to expand into the field of binoculars. He believed that there was a need for high-quality, portable binoculars that could be used by scientists, explorers, and other professionals in the field. The first Leica binoculars were introduced in 1920, and they quickly gained a reputation for their precision optics and exceptional build quality. These binoculars were designed with the same attention to detail and precision engineering as the company’s microscopes, and they quickly became popular with birdwatchers, © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_11

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hunters, and other outdoor enthusiasts. Over the years, Leica continued to innovate and improve its binoculars. In the 1930s, the company introduced the first binoculars with a roof prism design, which allowed for a more compact and lightweight design. This innovation set a new standard for binocular design, and it quickly became the industry standard. During World War II, Leica shifted its focus to producing military-grade optics for the German army. These binoculars were designed for use in combat situations, and they were highly prized for their durability and reliability. After the war, Leica returned to producing civilian binoculars, and the company continued to innovate and improve its designs. In the 1960s, Leica introduced a new line of binoculars that incorporated new materials and designs. These binoculars featured lightweight, aluminum bodies and multi-coated lenses, which improved image quality and brightness. The company also introduced a range of different magnifications and objective lens sizes, which allowed users to choose the right binoculars for their needs. In the decades that followed, Leica continued to innovate and improve its binoculars. The company introduced new features like waterproof and fog-proof construction, as well as high-performance coatings that improved light transmission and reduced glare. Leica also expanded its product line to include a range of different binoculars for different applications, including birdwatching, hunting, and outdoor recreation. Today, Leica remains one of the most respected names in the optics industry. The company continues to produce high-quality binoculars that are prized for their precision optics, exceptional build quality, and innovative designs. Whether you’re a professional scientist or an amateur birdwatcher, a Leica binocular is a top-­ of-­the-line choice that is sure to provide years of reliable performance and exceptional image quality. The Leitz Binuxit line of Porro prism binoculars were manufactured from 1927 through 1962 and were very popular back in the day. Even today, these beautifully made classic binoculars put up great images which are surprisingly bright and rich in color contrast. Today they are valuable collectors’ instruments. Leica’s most famous binocular, the Trinovid, is a line of binoculars that has been in production since the mid-1950s. The Trinovid was initially designed as a high-­ performance binocular for outdoor enthusiasts, birdwatchers, and hunters. Over the years, the Trinovid line has undergone several revisions and upgrades, incorporating new materials, designs, and features. The first Leica Trinovid binoculars were introduced in 1956. They were designed with a roof prism design, which allowed for a more compact and lightweight construction than traditional Porro prism binoculars. The Trinovid binoculars were also notable for their exceptional optical performance, with high-quality lenses that produced bright, clear images. In the 1960s, Leica introduced the Trinovid B series, which featured an improved design and a more robust construction. The Trinovid B series was also the first line of binoculars to incorporate rubber armoring, which made the binoculars more durable and resistant to damage from impact and moisture. Over the years, Leica continued to innovate and improve the Trinovid line. In the 1980s, the company introduced the Trinovid BA series, which featured an improved optical design and a multi-coated lens

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system. The BA series also incorporated a new eyepiece design that provided a wider field of view and greater eye relief, making the binocular more comfortable to use for extended periods. In the early 2000s, Leica introduced the Trinovid BN series, which incorporated new materials and features. The BN series featured a lightweight magnesium alloy body and a new focusing system that provided smooth, precise focusing. The BN series also incorporated a new anti-reflective coating on the lenses, which reduced glare and improved image clarity. In 2017, Leica introduced the latest iteration of the Trinovid line, the Trinovid HD. The Trinovid HD binoculars incorporate the latest advancements in optical technology, including high-definition glass and a new coating system that provides exceptional light transmission and color fidelity. The Trinovid HD binoculars also feature a new ergonomic design that provides a comfortable grip and easy handling. The Trinovid remained Leica’s flagship binocular until the introduction of their Ultravid line in the mid-2000s, but were continued as a lower cost alternative until Leica ceased production of the Trinovids altogether in 2015, much to the chagrin of many Leica fans. In 2016, Leica re-introduced their so-called entry-level premium binocular range in the Trinovid HD, which comprises four models; a 8× and 10×32 and an 8× and 10×42. Leica’s main production facility is still located in Wetzlar, Germany, where a small number of their employees are still located. Today, all of their binoculars are assembled in their large plant in Portugal, where Leica has been investing in since the 1970s.

The Trinovid 8×32 HD

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The Leica Trinovid HD range are very robust binoculars, with very thick rubber armoring. The eyecups are amongst the best in the industry and twist up to give the user several positions to suit their particular needs. They also can be removed from the binocular, which assists in cleaning the ocular lenses. Unlike their more advanced models, the Trinovid HDS don’t have a centrally locking diopter, but instead is located under the right ocular lens like that seen in the majority of mid-range models on the market. Like all Leica binoculars, they have a high aesthetic appeal, and indeed, just like all of their other optical wares, are widely accepted to be amongst the most beautiful binoculars to look at as well as look through. The Trinovid HDs are fully waterproof and fog proof, have very high-quality Schmidt-Pechan roof prisms, where the finest optical coatings are applied to generate their bright, high-contrast images. They also feature ED glass elements, although the company do not say what grade of ED glass they employ. The focus wheel is silky smooth for the most part, although my 8×32 unit did show up a very tiny amount of free play. Ergonomically, these are beautiful instruments to handle, right up there with the best binoculars currently available. And while they may not have their top of the line Aquadura hydrophobic coatings, the outer lenses do have a lesser grade of such coatings which is a lot better than none at all. Optically the Trinovid HDs are very good, yet many would also add “not outstanding.” My experience with the 8×32 model was very favorable but it did show up a fair amount of chromatic aberration, maybe too much for some people to tolerate. But having compared it with several excellent lower priced models, its overall optical performance proved to be a little lackluster among the better models out there. That’s partially reflected in the price tag though. These Trinovid HDs can all be had for under $1000 and that’s with a 10-year European warranty. The next series offered by Leica is their Ultravid HD line of high-performance binoculars. Widely considered to be one of the most beautiful binoculars to look at and through, these world-class instruments exude quality on every level. First introduced in August 2003, the Ultravid incorporated a host of state-of-the-art optical technologies built into a very compact optical tube assembly. The next development in the Leica Ultravid series came in 2007 when they added HD to their name. Finally in 2015, Leica launched their HD Plus series, which are currently still in production. The HD series introduced a fluorite objective lens element for better color correction and improved light transmission, going from 90% to 92%. The HD plus incorporated the finest Schott glass – the same as used by Zeiss in their flagship Victory SF models. In total Leica offer the Ultravid HD plus in no less than eight models: 8× and 10×32, 7×, 8× and 10×42, 8×, 10× and 12×50. Until recently, all Leica Ultravid binoculars were manufactured in Germany but the latest models are now being produced in Portugal. Ergonomically, the Ultravids are the dream ticket. The central focus wheel is ultraprecise and very reliable no matter what the weather throws at you. That’s due to the central hinge axle being made from titanium which is wear resistant. No matter if its −20° C below in winter or above+40° C in summer, the kinematics of the focus wheel remains the same. In a step up from the Trinovid HD series, the diopter

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adjustment is built into the focuser. Pull the wheel out to expose the scale and after making your desired adjustment, pop it back in again. Optically, the Ultravid HDs are a step up from the Trinovid HDs too with sharper images, better contrast and superior control of stray light and glare. Indeed, Leica are widely known for their superlative control of internal reflections and glare suppression. The color tone of the Leica Ultravids is also stunning to behold. Greens, browns and reds are beautifully reproduced, so much so that viewing through these binoculars can quickly become addicting. As you might expect, the Ultravid HD Plus range of binoculars are very nicely armored, totally waterproof to 5 m depth immersion and filled with dry nitrogen to keep the internal optical components from fogging up. The outer lenses are treated with Leica’s award-winning AquaDura coatings that makes water and oily deposits bead together and fall off so that you can continue to observe even in very wet weather. A few of the Ultravid HD line are especially noteworthy. The smallest and arguably the most beautiful of the series is the 8×32. Adored by birders especially, this marvel of optical and mechanical engineering weighs just over half a kilogram and delivers tack sharp images from edge to edge with wonderful color fidelity and that famous Leica contrast. Maximum brightness is ensured by Leica’s proprietary P40 coatings and their High-Lux system. Delivering a field of view of 7.7 angular degrees, it’s ideal for watching fast moving birds move from close by to far away. And because it’s so small and light, it can tucked away in a medium-sized coat pocket. The only gripe some customers have with the 8×32 Ultarvid HD Plus is the rather short eye relief: just 13.3 mm, making it quite a bit of a struggle for those who wear eyeglasses.  It may also be too small for some individuals who possess larger hands.

The Leica Ultravid HD Plus 8×32. (Image Credit: Paul Wehr)

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Another notable model in the Ultravid HD Plus series is the 7×42 model. This rare configuration offers a very large exit pupil (6 mm), which is especially useful in low light situations, such as dawn and dusk. And its generous 17 mm eye relief makes it especially easy to use with those who wear eyeglasses. For these reasons, the 7×42 is especially popular with hunters with its great 8-degree angle of view. Like all Leica binoculars, you’ll get a nice, padded case to protect your investment, a high-quality logoed neoprene neck strap and excellent quality rubber rain guards and objective lens covers. You’ll also receive a test certificate indicating that the instrument was quality assessed at several stages before it was shipped to the retailer, a 10-year warranty card and comprehensive user manual in multiple languages. As you might expect, the Ultravid HD Plus binoculars don’t come cheap. Expect to pay $1800 for the 32 mm models and $2500 for the largest 50 mm instruments. Leica also offer a dual magnification binocular in their innovative Duovid series. The Leica Duovid 8 + 12×42 and 10 + 15×50 binoculars are a significant departure from everything else on the market today. As their name implies, these binoculars actually feature two magnifications each. The 8 + 12×42 model can switch between 8× and 12× magnification, and the 10 + 15×50 model can switch between 10× and 15×. In so doing, the Duovids force us to adjust our thinking about multiple power binoculars in general. Normally, the reader would be ill-advised to purchase any binocular having a zoom capability, as their quality is almost invariably poor. But the Leica Duovid is not a zoom binocular, rather it offers two fixed magnifications: an 8 & 12×42 mm or a 10 & 15×50 mm. One amazing feature of these binoculars is that they are parfocal, that is, when switching magnification, the image remains in focus – if it’s sharp at 8×, it’s still sharp at 12× without re-focusing! The diopter adjustment is located in front of the focus knob. To adjust, pull it up towards the ocular lenses until it turns freely. The Duovids can be adjusted+/−3 diopters in a mechanism that is very sensitive – the slightest touch makes a big change. Push the knob back in to lock it in the desired place. The diopter also compensates automatically to retain sharpness when the magnification is switched. As you might expect from all the sophisticated optics inside, the Douvids are heavy instruments. The 8  +  12×42 model weighs over a kilogram. For handheld use, the 8 + 12×42 is the better option, as the 10 + 15×50 weighs significantly more (it’s 200 g heavier) and introduces more noticeable handshake. One other thing to mention about the Duovids is their short eye relief: 14.5 mm at the lower power and 14.3 mm at the higher power in either model. That might present some issues for those who wear eyeglasses. At $2500 and $2800 for the 8  +  12×42 and 10  +  15×50  mm, respectively, these instruments don’t come cheap. But in a way you’re almost getting two binoculars in one when you make your purchase, so the steep retail price doesn’t seem so high when you think about it in those terms! As discussed at length in previous chapters, Leica also market an extensive range of high-quality pocket binoculars in their Trinovid BCA and Ultravid series. The Trinovid BCA binoculars enjoy a very long and distinguished pedigree. The earliest models had rather low transmission owing to their lack of phase coatings and inferior antireflective coatings, but over the years these elegant instruments have been

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greatly improved. Today, they all feature Leica’s P40 coating technology and High-­ Lux treatments giving them light transmissions of the order of 90% over much of the visual spectrum. The BCAs come in two models; the 8×20 and 10×25 and are well armored in a grippy black rubber. The diopter is located on the right barrel near the objective and can be adjusted simply by rotating it clockwise or anti-clockwise. Described as splashproof, they are OK to use in light rain. They are also nitrogen purged internally to prevent them fogging up in adverse weather conditions. The eyecups are a real work of art. They simply pull up and lock rigidly in place.

The Leica Trinovid BCA 10×25

All the Leica pocket glasses are very elegantly designed in a dual hinge configuration. That means that they fold around two axes so that can easily fit in the palm of one’s hand. The focus wheel on the Trinovid BCAs is a little on the small side though, especially if you intend to use them while wearing gloves. The Ultravids come in two models; the 8×20 and 10×25. The basic models are armored in vulcanized black rubber and thus are known as BR. Leica also armor the Ultravids in an attractive leatherette covering (BL) but costs a few hundred dollars more than the BR models. And while it could be argued that the BL Ultravids look even more stylish and grand than the BRs, I have no doubt that the latter are better suited to extensive use in the great outdoors. The Ultravids have a more sophisticated locking diopter system too. There’s a little button located on the underside of binocular near the ocular lenses. By pressing and holding it in, you can then move the focus wheel to adjust your diopter setting which is indicated by a simple dial built into the focus wheel. By disengaging the button, your diopter setting is then locked in.

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Optically all of the Leica pocket glasses are excellent, but careful tests will show that the Ultravids are that little bit better. The aspherical lens elements ensure noticeably better off-axis performance than the Trinovid BCAs, yet all of these fine pocket glasses achieve this high level of performance without using ED glass. Could you live with only one of these optical and mechanical marvels? Well, I tried very hard for about a year, but ultimately larger formats won me over – particularly the 8×30 format – which is simply easier to use and offers a much more immersive experience, much closer to a full-size instrument. Having said that, I had great fun trying. These would make great gifts for those who like expensive gadgets. And because you can slip them in a handbag or small pocket, they can go everywhere with you. Expect to pay $400 for the Trinovid BCAs and $600 for the Ultravid pocket binoculars. Leica’s flagship models are the Noctivids. Considered by many to be the pinnacle of optical and mechanical engineering, their name is inspired from the Latin appellation for the Little Owl, Athene Noctua, and consist of just two models: an 8× and 10×42. Built like a proverbial tank, Leica first introduced the Noctivids in August 2016. These world-class instruments come in two colors: olive green or black. Following the example of Swarovski’s highly successful EL series with its innovative open bridge design, Leica based their Noctivids on a similar chassis design for better handling. The Noctivids feature the highest quality Schott Fluorite glass for very high contrast with those famous Leica colors. The so-called self-­ lubricating focus wheel ensures that it will operate flawlessly in temperatures as high as 50° C or as low as −40° C. Like the Ultravids, the diopter adjustment is made by popping out the focus wheel and rotating the dial until your preferred setting is achieved, then push the focus wheel in again and you’re good to go. The Noctivids have field flattening lenses but the field is not as flat as the Swarovski Els. The reason for this was that many EL users reported feeling a bit queasy from the rolling ball effect while panning them in the field. Leica reduced the degree of flattening at the edges so as to counteract the worst of these effects and, as a result, users report a far more natural, relaxed perspective. Compared with the top tier offerings from Swarovski and Leica, you might find the field of view of the Noctivids a little underwhelming; 7.7 angular and 6.4 angular degrees for the 8 and 10×42, respectively. In addition, those especially sensitive to chromatic aberration have reported significant false color issues with the Noctivids on certain targets, but for most users this is quite an acceptable compromise. All the Noctivids come with an excellent ensemble of accessories including a very high-quality cordura hard case to protect your investment. As you’d expect, these instruments don’t come cheap. Expect to pay $2800 for one. Finally, we’ve already discussed a number of state-of-the-art range-finding binoculars from the same company in a previous chapter. If you thought the aforementioned Leica binoculars were all that the company were about, you might be surprised to learn that Leica also are in the business of melding art and science together in the creation of their Trinovid classic series. Although their famous Trinovid line goes all the way back to the 1960s, the

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company recently re-invented this classic line with state-of-the-art optical technologies, combing the best of the old with the new including full nitrogen purging and waterproofing. One such model will be discussed later in the book. Make no mistake about it, these are arguably the world’s most beautiful binoculars with their gorgeous retro look but this author thinks they might be overkill for someone wanting to use them as day-to-day observing tools. Expect to pay a high price for these almost bespoke optical gems.

Chapter 12

Zeiss Binoculars

Zeiss is a company that has been producing high-quality optical instruments since the mid-nineteenth century. The company was founded by Carl Zeiss, a German optical designer, in 1846 in Jena, Germany. The first Zeiss binoculars were introduced in 1894 and quickly gained a reputation for their exceptional quality and precision. In the early years of the company, Zeiss focused on producing microscopes and other precision optical instruments. However, as the technology for making binoculars became more advanced, Zeiss saw an opportunity to expand into this market. The company’s success was in large part attributed to the hiring of optical geniuses such as Ernst Abbe and Otto Schott, whose many inventions led directly to improving optical quality in all of Zeiss’ early products. Today Zeiss continues to be a world leader in the design and marketing of high quality binocular optics in all price categories.

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A mid-1980s vintage Zeiss Jenoptem 10×50

Today, Zeiss is one of the most respected names in the world of optics, and its binoculars are used by hunters, birdwatchers, and other outdoor enthusiasts around the world. In recent years, Zeiss have outsourced some of their manufacturing to the Far East, first in Japan and most recently in China, where their entire Terra line of binoculars are now being assembled. The Zeiss Terra ED line are the company’s entry level series of binoculars, which comprises two pocket models: the 8× and 10×25, a compact 8× and 10×32 and finally their full-size 8× and 10×42. When I first got interested in binoculars, I was surprised to learn that the Zeiss Terra ED 8×25 I was using was actually made in Japan, but this was only for a short spell. Now, even the pocket Terras are being made in China. The move to Chinese production of the Zeiss Terra ED line raised quite a few eyebrows when it was first announced, with some folk expressing their horror that a world leader in sports optics production could invest in a communist regime. The reality on the ground revealed a different picture however. China is in the enviable position to have the manufacturing infrastructure needed to create exciting optical products at prices many more consumers can now afford. Without these products there would be far fewer stargazers and birders in the world. In a very real sense, the rise of China as a manufacturing superpower has grown these hobbies more than any other single event in human history. What’s more, the majority of entry-level and mid-priced binoculars on the market today are manufactured in China and the quality has steadily improved over the years, so much so that these other brands were undermining Zeiss sales. The Terra ED line was Zeiss’ answer to that challenge. They introduced the Terra ED line with the aim of becoming the best in the lower priced binocular class, and to some extent they have been successful.

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The Zeiss Terra ED Pocket 8×25

The Zeiss Terra ED binoculars are constructed from an advanced polymer chassis covered in grippy rubber armoring. They are fully water and fog proof and are packed full of quality optical components; Schott ED glass to minimize color fringing, BaK4 Schmidt Pechan roof prisms deliver an overall light transmission of 88%. The outer lenses are coated with Zeiss proprietary hydrophobic coating that repels water and greasy dirt thus requiring less cleaning. The focus wheels on the Terra EDs are quite impressive; they move smoothly with no play or backlash and allow good close focus but some individuals may find it too fast. Except for the pocket models which have their diopter adjustment mechanism located at the end of the bridge, all the larger models have a non-lockable diopter ring located under the right eyepiece. The twist-up eyecups are clad in soft rubber and rigidly click into place. My experience of the eyecups a few Terra ED models has been uniformly positive. They are very cleverly engineered and work better than many others I tested – sometimes on much more expensive models. I also like that Zeiss offer their Terra ED line in a variety of colors; green, black, grey and even orange! Optically, the Zeiss Terra EDs are quite impressive; sharp nearly to the edge, bright and vivid colors. Contrast is also excellent. In comparison to a number of other mid-priced models, they stand out for their exceptional control of glare. Their warranty is just 2 years though, not the 10 years you get by purchasing their more expensive models. That said, these economically priced binoculars from Zeiss are probably enough for the vast majority of people and there are plenty of positive testaments to their optical quality, ruggedness and versatility. My personal favorite from the Terra line is the 8×42 instrument which delivers great optical performance

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especially in dull lighting conditions where it really excels. It’s just a great travel binocular! The next line from Zeiss offers a noticeable step up in optical performance and ergonomic handling. I speak of course of the Zeiss Conquest HDs. This line comprises of 7 models: an 8× and 10×32, an 8× and 10×42, and three 56 mm aperture models in 8×, 10× and 15×. Manufactured for a time in Zeiss’ factory in Hungary, the Conquests are now exclusively made in Germany. The Conquests have better glass offering an even brighter view than the Terra EDs thanks to their 90% light transmission. Moving up to the Conquests, the polymer chassis is replaced by one made from Magnesium alloy, the waterproofness increases from 1 to 4 m, and the field of view is increased over the equivalent Terra ED model. Color correction is reported to be excellent in the Zeiss conquest, easily beating out lower-tier offerings from Leica for example, such as the Trinovid HD line in this capacity. The 32 mm and 42 mm aperture models of the Conquest series employ Schmidt Pechan roof prisms but the largest models in the series – those with 56 mm aperture – feature Abbe Koenig prisms – to maximize light transmission. As you might expect, these better built binoculars from Zeiss are also substantially heavier than the equivalent Terra ED model. For example, the 8×32 Terra weighs in at 510  g whereas the 8×32 Conquest tips the scales at over 630 g. So if you aim to travel light, you may wish to consider something lighter like the Terra. All of the Conquests come with an improved 10-year European warranty, so if anything should happen to your chosen instrument, Zeiss technicians will be able to take care of it for you. The Conquests vary in price from about $980 for the 32 mm models right up to $1800 for the 56 mm units. If the Zeiss Conquests fail to impress, why not move up to the company’s flagship line: the Victory series. There’s something for everyone here. Starting with two small pocket binoculars – the Zeiss Victory pocket 8× and 10×25 – these are widely regarded as some of the most advanced pocket binoculars in the world. Unlike most other pocketable glass out there, the Zeiss Victory pockets have an asymmetrical hinge design, which means they fold around a single hinge rather than the more common double hinge design. This may sound strange but it’s a very clever bit of engineering and works extremely well in practical use. What distinguishes the Zeiss Victory pockets from the Terra ED pocket binoculars is the use of even higher quality ED glass in the form of fluorite crystal as well as their noticeably wider field of view. The 8×25 Victory pocket, for example, puts 7.6 degrees of field before your eyes. Compare that to the Terra ED 8×25 which delivers a 6.8 degree field. It also delivers a very bright image with 91% light transmission. The view, as many user reports attest, are uniformly excellent. Indeed, many have compared it to that delivered by some of the best 30–32  mm models. Its only weakness is the small exit pupil, which limits its use in low light situations. It’s also a bit underwhelming for astronomical observations, except perhaps on a bright Moon. As you might expect, these hand sized binoculars don’t come cheap. Expect to pay $900 for the privilege of owning one. The Victory line doesn’t end with these wonderful pocket binoculars. Zeiss has developed a series of state-of-the-art compact and full-size binoculars in their

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Victory SF, SFL and HT ranges. The Zeiss Victory SF binoculars are the ultimate in nature watching binoculars. Made with Zeiss’ new proprietary Ultra-FL glass, these binoculars have their optical components rebalanced to push the center of gravity of the instrument towards the eyepiece end, so they feel lighter than their published weight, at least while you’re looking through them. A triple open bridge design provides structural stability while still leaving room for three fingers from both hands between the barrels. A newly designed 7-lens configuration with a field flattener lens provides edge-to-edge sharpness while yielding an astonishing 92% light transmission. The Zeiss Victory SF binoculars are available in 8× and 10× magnifications with apertures in the 32 mm and 42 mm class. Here we’ll take a closer look at the technology behind the 8×32 mm Zeiss Victory SF. The 8×32 Zeiss Victory SF has a very impressive field of view of 8.9 degrees. If you’re not familiar with this field size, you’ll be blown away when you first look through it. That’s an enormous field – even larger than my beloved Nikon E II. The newly re-designed twist up eyecups offer 19 mm of eye relief which is even more generous than what the 42  mm models offer. The prisms are fashioned with the highest quality phase-coated BaK-4 glass. They are still fully broadband multi-­ coated with Zeiss’ proprietary T* coatings and the outer lenses are treated with the LotuTec coatings to repel water and dirt and to protect them from accidental scratching. The Zeiss Victory SF 8×32 binoculars are quite lightweight, tipping the scales at only 612 grams due to their low-density magnesium alloy chassis. They also feature an over-sized focus wheel that is centrally located and silky smooth to operate. Furthermore, the matte black rubber armoring provides a secure grip, almost as though the binocular is clinging to your hand. Additionally, the balance on the 32-mm SFs is perfect, making them feel lighter than their actual weight. These binoculars are also compact, measuring just 5.9 inches (15 cm) long with the eyecups folded down and just over 6.25 inches (16.1 cm) long with the eyecups extended. The binoculars are comfortable to wear all day long, with an interpupillary distance range of 54–76 mm. The 8×32 Victory SF binoculars are also dry nitrogen-purged and sealed, making them completely waterproof, dust-proof, and internally fog-proof. The focusing mechanism of the 32-mm Victory SFs is smooth and precise, requiring only 1.6 turns of the focus knob to go from minimum close focus to infinity. The focus knob is covered in broad ridges, providing a secure grip even when wet. The minimum close focus distance is 6 feet (about 2 meters), although this can vary somewhat depending on the user. The helically adjustable eyecups have two stable detents between fully in and fully out, making it easy for most users to find a comfortable position. The locking diopter mechanism is easy to use and located on the ocular side of the uppermost bridge. The rain guard is made of two soft rubber cups linked by a flexible bridge that fits firmly over the eyecups, while the objective lens caps are made of flexible rubber and fit up into the armoring of the barrel ends. The strap provided is comfortable, but a harness strap is recommended. The case is well-padded and made of water-shedding, Cordura-like material, but it is only large enough to accommodate the binocular with lens caps on, and it won’t fit anything

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else. The Zeiss Victory SF 8×32 binoculars retail for $2500, while the 42  mm Victory SF costs an additional £300. One complaint made by some Victory SF users was their heftiness. That comes with the territory for such an advanced optical system unfortunately. The 32 mm models weigh in at just over 600 g and the 42 mm units are close to 800 g. Recently Zeiss addressed this issue by bringing to market two new models in the SFL series; an 8×40 and a 10×40 and more recently the smaller 8× and 10×30 models. The slight reduction in aperture allowed Zeiss engineers to use thinner lenses and space them closer together than in the SF models, making the instrument about 20% lighter and 13% smaller than the 42 mm SF models. But in other ways, the SFL models are quite a bit different to their more expensive SF cousins. For example, the diopter is non-locking and relocated under the right ocular, the field of view is also reduced compared to the SF models. The light transmission of the SFL binoculars is also reduced from 92% to 90%. Retailing for about $1800, some experienced observers have quipped that although the optics are really good, it performs more like other $1k binoculars, so maybe not the best value for money. Another new series launched by Zeiss are the so-called HT models, currently available in 8× and 10×54 mm. The ‘HT’ in the name stands for High Transmission and a cursory look at their light transmission reveals an extraordinarily high 95%! The Zeiss HT were the replacement for their now discontinued FL series. To achieve this level of light transmission Zeiss combined HT Schott glass, their famous T* multilayer coating and the employment of Abbe Koenig prisms. Optically, the Zeiss HTs are real sharp shooters, with central sharpness right up there with the best. The HT glass has higher transmission at blue wavelengths making particularly good to use in low light conditions. Their edge of field performance is not as good as in the SF models however, owing to the lack of field flattening lenses. That said, the HT binoculars are a little lighter (weighing in at about 1100 g) than standard 8×56 low light binoculars and perform excellently at dusk and dawn, so popular choices for discriminating hunters wanting to squeeze the last details out of their targets when the sun falls out of the sky. These big glasses command big retail prices of the order of $2800.

Chapter 13

Swarovski Binoculars

Swarovski binoculars are renowned for their exceptional quality and precision, and are highly regarded by birdwatchers, hunters, and other outdoor enthusiasts. The Swarovski company has been producing binoculars since the 1930s, and over the years, they have developed a reputation for producing some of the finest optics in the world. The story of Swarovski binoculars begins in 1895, when Daniel Swarovski founded his crystal manufacturing company in Austria. Swarovski crystals quickly became known for their exceptional quality and brilliance, and the company soon expanded its operations to include a range of optical instruments, including telescopes, binoculars, and rifle scopes. The first Swarovski binoculars were introduced in the 1930s, and they quickly gained a reputation for their high-quality optics and precision engineering. These early binoculars were designed for military use, being used by the German army during World War II. After the war, Swarovski began to focus on the civilian market, and their binoculars became popular with birdwatchers, hunters, and other outdoor enthusiasts. Throughout the 1950s and 60s, Swarovski continued to refine their binocular designs, introducing new features and improvements that made their binoculars even more reliable and effective. In 1967, they introduced the Habicht binocular, which quickly became one of their most popular models. The Habicht was known for its lightweight design, wide field of view, and exceptional image quality, and it remained a popular choice for birdwatchers and hunters for many years. In the 1980s, Swarovski introduced their EL (Ergonomic and Light) series of binoculars, which represented a major step forward in binocular design. These binoculars featured a revolutionary new focusing mechanism that made them much easier to use than traditional binoculars. They also incorporated a number of other features that made them more comfortable and convenient to use, including a lightweight design, ergonomic grip, and adjustable eyecups. Over the years, Swarovski has continued to innovate and improve their binoculars, introducing new features and technologies that have made their optics even more reliable and effective. In 345 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_13

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2008, they introduced their Swarovision technology, which dramatically improved image quality and clarity. This technology has since been incorporated into many of their binocular models, including the EL, SLC, CL and NL Pure series. Today, Swarovski binoculars are considered some of the finest optics available, and are highly prized by birdwatchers, hunters, and other outdoor enthusiasts. They continue to innovate and push the boundaries of what is possible in binocular design, and are likely to remain at the forefront of the optics industry for many years to come. Though officially founded in 1949, the first Swarovski binoculars, a little 6×30 Porro prism binocular, were in fact being made as early as 1935 by the company’s founder, Wilhelm Swarovski. Their first products were classically designed Porro prism binoculars – the famous Habicht series – which I’m delighted to say are still in production today. It is these binoculars that we will first turn. As explained earlier in the book, Porro prism binoculars are a study in optical simplicity. Compared with roof prisms, they avoid a whole host of technical problems that need to be alleviated before they can even compare with decent Porro prism designs. Today, the Swarovski Habichts boast the highest light transmission of any modern binocular – a staggering 96%! This parameter was actually measured by the Dutch physicist, Gijs van Ginkel, who declared, “I have investigated the quality of the Habicht 8×30 Porro and at first I could not believe what we found. I have had many Porro binoculars in my hands, but the image quality of the Habicht is excellent: very sharp image quality, bright and with perfect color reproduction. We measured 95% light transmission, but the latest ones come up to 96%, while the spectrum is flat as the Dutch country side”. Indeed this figure is better than any modern roof prism model with the finest glass and coatings – something that is truly humbling in my opinion. And it’s even more remarkable considering the Habichts do not employ ED glass! The smallest Habicht is the 8×30 W model. Delivering a 7.75 degree field, the images are stunningly bright, vibrant and color pure. Contrast is also exceptional. The sweet spot is large but becomes noticeably more blurry right near the field stops. The Habicht series is also notable for its waterproof sealing and dry nitrogen gas purging; the first company to do so with Porro prism binoculars. But this waterproofness comes at a cost: the sealing off of the interior makes the focus wheel very stiff making fast focusing a bit of a chore. That’s not something desirable if you intend to watch fast moving targets like birds in flight. That said, for most users, a stiff focuser is an acceptable compromise for such excellent optical performance. Another deficiency in the Swarovski Habicht – and indeed most other Swarovski binoculars – is that there is some glare and internal reflections – a consequence I suppose of their extraordinary light transmission. The Habichts are available in larger sizes including a 7×42 and 10×40  in armored (the GA models) or nonarmored versions. These can be had for quite reasonable prices (as Swarovski binoculars go): $1000 for the 8×30 W and $1200 for the 7 ×42 model. Swarovski are world leaders in the design and marketing in elegant and durable pocket binoculars, including their long-established CL pocket binoculars in 8× and 10×25. These dual-hinge designs ensure that they fold down neatly into

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pocket-­sized instruments you can hold in the palm of your hand. These ruggedly designed pocket binoculars come in two colors, green and anthracite, offer excellent eye relief with their beautifully engineered twist up eye cups and impressive fields of view. They are also fully waterproof and fog proof. They are considered near ideal as travelling binoculars, or for those who want maximum optical performance from a small, ultraportable package. Most recently, to much international clamor, Swarovski launched their latest pocket glass, the 7×21 CL Curio. The brainchild of the distinguished Australian designer, Marc Newsom, the CL Curio exudes elegance, with its dual hinge design and broad rectangular bridge. Two color choices are offered: burnt orange and anthracite.

Ultraportable Elegance: The CL Curio 7×21. (Image Credit: Sam Shepherd)

The diopter adjustment is a small ring located at the far end of the bridge. The central focus wheel is silky smooth, but some users may find it a bit small, especially when using gloves. As you’d expect from a top manufacturer like Swarovski, the CL Curio offers excellent edge-to-edge sharpness with top-notch contrast and color rendition. It’s also fully waterproof and fogproof. The twist up eyecups offer 21 mm of eye relief, though the real value is closer to 18 mm, as some experienced binocular enthusiasts have noted. What is perhaps most impressive is the Curio’s expansive field of view: a whopping 7.7 degrees, making it the widest of any pocket binocular currently on the market. This is in part attributed to the choice of 7× magnification. Such engineering elegance doesn’t come cheap though. Don’t expect much change out of $750. The Swarovski CL series doesn’t end there; perhaps the most popular choice among birders especially is the CL Companion, available in 8× and 10×30. The CL Companion has enjoyed several design alterations since it first appeared some 20 years ago. The latest models have several attractive design features that make them easy and comfortable to hold. The textured rubber armoring provides a firm grip and at just 490 g, they can be held steady with one hand while the other hand carries other items. The eyecups can offer a maximum of 16 mm eye relief and can be twisted up and down, even staying in place halfway down. However, setting the

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diopter requires pushing the center of the focus wheel. Once set, it stays in place well. The focus wheel is slightly wider than a finger and has ridges that make it easy to use while wearing gloves. It turns smoothly, taking just over one-and-a-half clockwise turns from close focus to infinity. The binoculars have a close focus of around 3 m and produce a bright, natural-­ colored image with a field of view of 7.5 degrees. The image is sharp up to the edge, providing no tunnel vision feeling. They come with removable tethered objective lens covers that are excellent, without bouncing up and obscuring the lens. There is also a good rain guard, although the strap is just decent and could be replaced with Swarovski’s neoprene strap for long-term use. The binoculars come with one of three accessory packages- Wild Nature, Northern Lights, and Urban Jungle. Each package contains an excellent, roomy carrying case with a strap. The Urban Jungle package was tried, and the strap was good, but the other packages’ straps looked more suitable for carrying them around all day. The cost for one of their packages is around $1300.

Big, high-quality glass: the Swarovski SLC 8×56. (Image Credit: William Lewis)

Swarovski Optik’s SLC series of high-performance binoculars have earned high praise, and the range currently includes three models with varying magnifications and objective lens sizes. The Swarovski SLC 8×56 is an excellent option for wildlife observation during low light conditions due to its 93% light transmission, thanks to the 56 mm HD objective lenses with sharpness and light response to the edge. These binoculars are well-balanced, making them suitable for extended viewing sessions without causing fatigue to the user’s arms. The SLC 8×56 also has a generous 23 mm eye relief, providing relief to the eyes. The 7.6-degree field of view adds to its searching capabilities. The 10× and 15×56 models are designed for customers who want to observe more detail at longer distances but require proper mounting on a tripod or monopod to prevent shake-induced image blurs. As with all SLC models, they are waterproof, nitrogen purged, and rubber armored, and the company offers a global lifetime warranty.

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One of the most innovative binocular series developed and marketed by Swarovski Optik is their world-famous EL series of high-performance instruments. First launched back in 2007, a second-generation EL series hit the market in 2012, followed by a slightly tweaked third generation EL which came out in 2015. The El series  originally  compromised six models in all, an 8× and 10×32, an 8.5× and 10×42, and the largest models of 10× and 12×50. At the time of writing the 32 mm models have now been discontinued. Swarovski has packed an incredible amount of high technology features into these binoculars including their Swarodur, Swarotop and Swaroclean coatings which ensure long life, high light transmission as well as exceptional protection from the elements.

A First-Generation Swarovski EL 8.5×42

I had the opportunity to test drive a first generation EL 8.5×42. After 12 years of use in all sorts of conditions, it was still functioning perfectly. The lockable diopter setting was easy to access by popping the focus wheel out, turning it to your desired setting before popping it in again. Swarovski were the first to introduce their innovative open bridge design, which was followed by the other big binocular companies like Zeiss and Leica, who eventually introduced open bridge models of their own. This design allows one to get an excellent grip of the binoculars even with one hand. And it certainly does what it says on the tin. The focus wheel moves with a feeling like its gliding over sandpaper, creating just the right level of friction against your finger. The image is extremely sharp, right to the edge, thanks to the built-in field flatteners, but the extreme flatness of the edge of the field makes many users sick, including yours truly, while panning across a scene. That’s the dreaded rolling ball effect. Contrast and color correction are very true to life. This earliest model EL 8.5×42 delivered a field of only 7.4 degrees but the later models have widened this significantly. I did notice some glare though, while panning in the direction of the Sun, and also some prominent veiling glare looking up at the topmost boughs of a tree against a bright overcast sky, as other have reported, but otherwise the

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experience was impressive. After Swarovski introduced their new flagship series in the NL Pure, the cost of the EL binoculars was significantly reduced and can be secured for about $1600 for the 32 mm models and $3000 for the 12×50. Swarovski has launched the NL Pure series of binoculars, which many believe to be the next step in the evolution of binocular optics and ergonomics. With a sleek, single bridge connection and a slim body, the NL Pure is a radical departure from the EL series, which was Swarovski’s flagship model. While the EL series will continue to be available, the NL Pure leads the way. The new binoculars are built like a tank and have a weight of 640 g for the smallest 32 mm models and 840 g for the 42 model, excluding the strap. The NL Pure was designed to achieve two main objectives: to improve the viewing experience by increasing the field of view and to improve its handling in the field. The field of view is just over 9 angular degrees  in the most popular  × 42 model, which greatly enhances the overall viewing experience. The new body shape, with its mid-line barrel narrowing, and flattening, allows for perfect balance while also providing superb comfort for fingers to wrap around the chassis, maintaining grip and allowing for perfect control of the focus wheel. The central focus wheel, which is just over one finger’s width, takes approximately one quarter of a turn to sharply image targets between 10 m and infinity. The close-focus distance of 2 m is a significant improvement over the EL series. The NL Pure also has a diopter system that is a complete departure from the EL series, with an integrated narrow ring within the bridge for fingertip adjustment with a subtle click stop, allowing for easy and precise adjustment. The twist-up eyecups are state-of-the-art, ‘semi-locking’ in six positions, allowing the entire field of view to be viewed with glasses or without. The image quality of the NL Pure is stunning, with impressive color fidelity, brightness, and sharpness. The wide, flat field of view creates a sensation of depth and 3D imagery, with sharpness to the very edges and negligible curvature. Chromatic aberration is vanishingly low, creating world-class contrast. The NL Pure comes with a heavy-­duty rain guard to protect the oculars and clip-in objective covers that were introduced on the EL back in 2015. The soft, padded carry case is eco-friendly. However, the NL Pure’s weight of 840 g may be a drawback for some users during prolonged use, and the price tag of £2370 may be too high a barrier for some.

Chapter 14

Nikon Binoculars

Nikon is a well-known brand in the world of optics, and their binoculars are highly regarded for their precision and clarity. The history of Nikon binoculars stretches back more than a century, and the company has been at the forefront of optical innovation since its inception. The story of Nikon binoculars begins in Japan in 1917, when a group of leading Japanese optical manufacturers formed a company called Nippon Kogaku K.K. The company’s mission was to produce high-quality optics for a range of applications, including cameras, microscopes, and telescopes. In the 1920s, Nippon Kogaku began to focus on the development of binoculars, and in 1921, they introduced their first model, the Porro I. This binocular was notable for its compact size and high-quality optics, and it quickly became popular with birdwatchers and other outdoor enthusiasts. Throughout the 1920s and 30s, Nippon Kogaku continued to refine their binocular designs, introducing new features and technologies that improved performance and reliability. In 1933, they introduced their first waterproof binocular, which was designed for use in marine environments. During World War II, Nippon Kogaku produced binoculars and other optical instruments for the Japanese military, and their products were highly regarded for their quality and precision. After the war, the company resumed its civilian operations, and began to expand its product line to include a range of consumer optics. In the 1950s and 60s, Nippon Kogaku continued to innovate and push the boundaries of binocular design. In 1955, they introduced their first high-powered binocular, the 8×30 Monarch. This binocular was notable for its exceptional image quality and brightness, and it quickly became popular with birdwatchers. In the 1970s and 80s, Nippon Kogaku changed its name to Nikon Corporation, and continued to develop new and innovative binocular designs. In 1988, they introduced their highly popular Action Series binoculars, which featured a new focusing mechanism and improved image quality. In the 1990s and 2000s, Nikon continued to innovate and improve its binocular designs, introducing new features and technologies that improved image quality, durability, and performance. In 1999, they introduced their ED (Extra-Low © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_14

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Dispersion) glass technology, which dramatically improved color accuracy and image sharpness. This technology has since been incorporated into many of Nikon’s binocular models, including the Monarch and EDG series. Today, Nikon binoculars are highly regarded for their precision, clarity, and reliability. They also have some of the best quality control in the entire industry. They continue to push the boundaries of what is possible in binocular design, and are a popular choice for birdwatchers, hunters, and other outdoor enthusiasts around the world. With a long history of innovation and excellence, Nikon is sure to remain a leading brand in the optics industry for many years to come. In 2001 Nikon established a separate, independent company for its sport optics – primarily made up of Nikon binoculars and spotting scopes. Today, you’ll find Nikon optics in daily use by bird watchers, biologists, astronomy enthusiasts, hunters, golfers, and many more. Starting at the cheap end of the market, Nikon’s Chinese factories are churning out decent quality pocket binoculars in the multicolored Aculon T51 in 8×24 and 10×24. Users report good results with these inexpensive and ultraportable instruments. These Aculons sport decent sized fields of view- 6.2 degrees for the 8× model and 5.4 degrees for the 10× instrument. The eyepieces twist up but those who wear eyeglasses might find their eye relief a little tight (~12 mm). Although these are roof prism models, it is doubtful that they have any phase correction coating, which might render the images a bit dimmer than higher quality pocket binoculars. Still for about $100, they’re not bad at all.

The Nikon Aculon 16×50

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The Aculon range also extends to larger binoculars – all Porro prism design. The Aculon A211 series consists of a number of models including a 7×35, 8×42, 10×42, and models in the 50 mm aperture class with magnifications of 7×, 10×, 12× and 16×. Incidentally, Nikon also market a zoom Aculon 10–22×50 but I’ll confine my discussion to the fixed magnification here. The A211 Aculons have a classic Porro prism design with good quality BaK4 prisms and all optical surfaces have a multilayer coating delivering bright and high contrast images. I tested two of these models, the 8×42 and the smaller 7×35. The Aculons are covered in a decently thick rubber armoring, have a large, smoothly moving central focus. The Aculons have twist up eye cups, but eye relief is tight for eye glass wearers. The 8×42 offers a very generous 8.0 degree field and the aspherical elements do help keeping the image sharp across most of the field. I normally extend the eyecups up to their furthest setting, but I found that moving them down one step helped decrease glare somewhat. The 8×42 displayed quite a lot of lateral (off axis) color though. Indeed, I don’t think I’ve experienced such high levels of lateral color in any other binocular I’ve tested. The 7×35 is considerably lighter and has a wider field of view (9.3 angular degrees to be exact). Nikon have not rested on their laurels with the Aculon series. They also market a much more heavily armored product in their Action EX series, which consists of a 7×35, 8×40, and no less than four models in the 50 mm aperture class with magnifications of 7×,10×, 12× and 16×. I field tested the 7×35 some time ago and the first thing that strikes you about it was its chunkiness. The armoring makes it very easy to grip securely. These Action Exs are all waterproof and fogproof, making them suitable for hard work in the great outdoors. Optically, they are very decent with wide and well corrected fields of view. The 7×35 I field tested had an impressively wide field over 9 degrees. As you’d expect from a binocular in this midpriced price range, there is some field curvature which blurs the edge of the field but the field is so wide that there is plenty to keep you occupied. It’s a great binocular for scanning landscapes with its pronounced 3D images. Depth of field is very generous. Focus in the middle distance and everything in the background is still sharply in focus. Despite its small aperture, the exit pupil of 5 mm means that images remain bright even in low light situations. It’s also a very decent stargazing binocular, great for sweeping up vast shoals of stars in the Milky Way. The Action EX binoculars retail for between $150 and $220, so offer great value for money.

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Built for the great outdoors: the Nikon Action EX 7×35

Both the Aculon and Action Ex models are made in China, but Nikon have reserved their finest Porro prism binoculars for their Japanese plant. I speak of course of the venerable Nikon EII 8×30 and 10×35. These state-of-the-art compact Porro prism binoculars have immaculately sculpted magnesium alloy chassis and wonderful expansive fields of view (8.9 degrees for the 8×30 and 7.2 degrees for the 10×35). Widely regarded as one of the best binoculars in their aperture class in the world, they deliver tack sharp images across most of their fields, with excellent brightness and contrast thanks to highly advanced antireflection coatings. The 8×30 remains my personal favorite binocular. It never fails to throw up truly remarkable images and is a pure joy to hold in my hands. The focus wheel of the EIIs is covered in soft rubber and smooths with silky smoothness. The diopter ring is located under the right ocular lens. It takes a considerable amount of effort to move it, so there’s little chance of it moving out of place in field use. And while they are not waterproof or nitrogen gas filled, my own tests show they can be used perfectly well in cold weather. Furthermore, if stored in an airtight Tupperware container with lots of activated silica gel desiccant it can be rendered effectively fog proof. As you might expect, the Nikon E IIs don’t come cheap. And I hear they’re becoming difficult to find. But if you’re a diehard Porro prism binocular fan, these instruments are a must have.

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Portable Perfection: The Nikon E II 8×30

Nikon don’t just produce an extensive range of conventional Porro prism binoculars, they also market a number of compact reverse Porro prism binoculars in their Travelite series. The Nikon Travelites come in a variety of magnifications; 8×, 9×,10× and 12×25. The reverse Porro prism design, where the eyepieces are further apart than the objective lenses instead of the other way around, is a popular one for compact binoculars. While reverse Porro prism designs won’t usually fit comfortably in a shirt pocket, they come pretty close, sometimes have excellent optics and carry a significantly lower price tag than comparable roof prism “pocket binoculars.” The Travelites come in two choices of chassis. The Travelite VI is made from polycarbonate ensuring a tough but sturdy housing for the optics. All the Travelite VIs weigh about 270 g. The Travelite EXs, in contrast, have a die cast aluminum chassis for extra durability. They are also nitrogen gas filled and o ring sealed making them fully waterproof. I tested an older Travelite EX 8×25 out but had some issues with it optically, so I returned to using true pocket sized binoculars (of the folding variety). Most users report decent optical performance with these reverse Porro prisms binoculars though, and so represent good value for money overall. We now turn to the extensive range of roof prism binoculars developed by Nikon, all the way up to the most expensive binoculars ever made – the famous WX series. Nikon recently revamped their Prostaff range of roof prism binoculars, launching their new Prostaff P3 and P7. These are both offered in four models: 8× and 10×30 and 8× and 10×42. Owners report very good optics, with the P3 and P7 8×30 models offering one of the widest fields of view of any roof prism binocular at a

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whopping 8.7 angular degrees! The images are bright, with excellent sharpness and contrast. They are also very lightweight thanks to their plastic housings. They are also fog proof and waterproof. Their downside? Too much plastic. One buyer of the 8×30 P7 reported that the lockable diopter ring broke after just a few days of use! One wonders whether the P3 might be the better buy since the right eye diopter is non lockable. But their very economical prices will likely attract a lot of customers. Moving up in mechanical and optical quality, Nikon have also revamped their Monarch 5 and 7 series, adding M5 and M7, respectively to their names. The Monarch M5s come in three models, 8×, 10× and 12×42, feature ED glass and dielectric coatings for brighter images than the Prostaff series. Finally, the Monarch M7s are another step up in optical performance offering larger and better corrected fields of view. All of the Prostaff and Monarch M5 and M7 binoculars are manufactured in China, but Nikon reserve their best roof prism instruments for their best Japanese factories. The Monarch HGs are another leap forward in optical and mechanical features and come in four models, the compact 8× and 10×30 and the full size 8× and 10×42. Their chassis of the HGs is made from a more durable and tough magnesium alloy covered by a thin rubber armoring which gives them a very stylish, retro look. Optically, these high-end instruments have the highest-grade ED glass for superb color correction and contrast rendering. They also feature a field flattening optical system for improved edge-to-edge sharpness. The wide-angle eyepieces slightly wider fields of view than the Monarch M7s. Mechanically, the focuser is buttery smooth and responsive to the slightest touch. I also liked the locking diopter under the right eyepiece. The Monarch handles beautifully but some feel it is a bit too lightly armored no doubt to increase its esthetic appeal. The 8×30 Monarch HG I tested was a very fine binocular with great contrast, edge of field sharpness and very low regarding chromatic aberration. It did have a couple of issues with it though; I experienced frequent blackouts and the rolling ball effect common on binoculars with flat field optics. If you think the Nikon Monarch HG represents the pinnacle of optical and ergonomic performance form a roof prism binocular, you might be surprised by Nikon’s flagship binocular offerings in the form of the EDG series, which comprises of 5 models in all: an 8× and 10×32, and a 7×, 8× and 10×42. The EDG brand was born of Nikon’s commitment to provide a premium lineup of the finest instruments in the field of sport optics. In combination with Nikon’s many leading-edge technologies, including both optical and mechanical  touches, these exceptional products can deliver a spectacular field of view, and performance that Nikon claims, “goes beyond the nature and outdoor enthusiast’s wildest dreams.” The original EDGs received some modifications before Nikon launched their EDG II series, the current series in production. The EDGs are packed full of state-of-the-art features that exceed the quality of even the Monarch HGs; the finest BaK4 prisms, dielectric coatings, ED glass and a built-in field flattening system. The armoring is more substantial than that found in the HG series and feel great in the hands. The diopter system is integrated into the focus wheel like that seen in high-end Zeiss, Swarovski and Leica binoculars.

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Owners report sensibly perfect images with amazing brightness, contrast and color correction. Indeed, the EDGs are reported to have some of the lowest chromatic aberration levels of any binocular on the market, with one reviewer calling them “Japanese Ultravids.” Unlike other binoculars with field flattening optics, many owners report the lack of the dreaded rolling ball effect by introducing just the right amount of pincushion distortion. Any room for improvement? Well, measurement of light transmission levels show yield values of about 88% – a tad lower than the top offerings from the leading European manufacturers and so may benefit from a new High Transmission (HT) glasses, but the improvement would probably be perceived as marginal by most users. Will we see a EDG mark III? Time will only tell. Last but certainly not least, Nikon have also produced arguably the most sophisticated binocular dedicated to low power star gazing. Called the Nikon XW 10×50 IF, this 2.5 kilo monster is universally considered to be the jewel in the crown of optical and ergonomic excellence, and is especially designed for the most discerning stargazers who want the very best that technology can deliver and are willing to pay for it. It features a highly advanced field flattening optical system with edge-to-­ edge sharpness, with a huge field measuring 9 angular degrees. 3 ED elements built into the optical train help deliver uncompromising clarity and color correction unmatched by any other binocular on Earth.

The Superlative Nikon WX 10×50. (Image Credit: Holger Merlitz)

The highest light transmission is guaranteed thanks to phase corrected Abbe Koenig prisms. As you’d expect, the entire optical system is treated to Nikon’s finest multilayered coatings. The Magnesium alloy chassis ensures a durable and tough

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housing. You might think individual focus eyepieces are not necessary these days but for astronomical observations they are ideal as you can micro-adjust both barrels for the finest, pinpoint stellar images. Both eyepieces offer a generous 15.3 mm of eye relief and the instrument is waterproof down to 5 meters for 10 min. One gets the impression that the 10×50 WX IF was a labor of love for Nikon optical and mechanical engineers and the owners of this instrument have only expressed universal praise for this magnificent instrument. Expect to pay up to $8800 for the privilege of owning and using such an instrument!

Chapter 15

Vortex Binoculars

The Vortex Diamondback HD 10×50

Vortex Optics is an American company that has become a major player in the optics industry, particularly in the field of binoculars. The company was founded in 2002 in Middleton, Wisconsin, and has quickly gained a reputation for producing high-­quality binoculars that are both rugged and affordable. The history of Vortex binoculars is relatively recent, but the company has made a significant impact on the market in an impressively short amount of time. From the beginning, Vortex has 359 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_15

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focused on producing binoculars that offer exceptional value for the price, without compromising on quality or performance. One of the key features of Vortex binoculars is their rugged construction. Vortex uses high-quality materials and construction techniques to ensure that their binoculars can stand up to the toughest conditions. Many Vortex binoculars are also waterproof and fog proof, making them ideal for use in a variety of outdoor environments. One notable feature of Vortex binoculars is that they are not purged with dry nitrogen gas but with the weightier noble gas, argon. At first glance, since its atomic mass is greater than that of nitrogen, it has been claimed that it ought to diffuse out more slowly than nitrogen. But after consulting with some work by Holger Merlitz, in his excellent book, The Binocular Handbook, such reasoning turns out to be flawed. Merlitz pointed out that the predominant factor influencing the rate of diffusion is the difference in partial pressure of the gas between the inside and outside of the binocular. Since the level of argon in the outside air is only about 1%, filling the binocular with dry argon gas will create a much stronger concentration gradient (100% inside to 1% outside) than that obtained using dry nitrogen (100% inside to 78% outside). And this means that the argon will actually diffuse out at a faster rate than nitrogen, all other things being equal! Another key feature of Vortex binoculars is their impressive optical performance. Vortex uses high-quality lenses and coatings to ensure that their binoculars produce clear, bright images with excellent color accuracy and contrast. Many Vortex binoculars also feature phase-corrected prisms and ED glass, which help to improve image sharpness and clarity. The company offers a wide range of binocular models, from compact models that are perfect for hiking and travel, to larger models that are ideal for birdwatching and other outdoor activities. In addition to its high-quality binoculars, Vortex is also known for its excellent customer service. The company offers a VIP Warranty, which covers all Vortex products against defects in materials and workmanship, regardless of the cause of the damage or the age of the product. This warranty is transferable and does not require a receipt or proof of purchase, making it easy for customers to get their Vortex products repaired or replaced if they encounter any issues. Overall, Vortex binoculars are an excellent choice for anyone who is looking for high-quality optics at an affordable price. As mentioned in a previous chapter, Vortex also market their well-regarded Fury range-finding binoculars. Vortex’s business model is to offer up the best quality binoculars within their price class. Starting with their least expensive binoculars, Vortex market a few Porro prism binoculars in the form of their Vanquish and Raptor. The Vanquish series includes two models, 8×26 and 10×26, both of which are reverse Porro design. They are small, lightweight and compact. I tested out the 8×26 but wasn’t too impressed. Even though the optics are fully multicoated and have high quality BAK-4 prisms, the image it served up was low in contrast due to the presence of too much glare. Still they seem popular enough with outdoor enthusiasts. The Vortex Raptors are traditional Porro prism binoculars and come in a choice of two models: 8.5×32 or 10×32. These are a good step up in optical performance from the Vanquishes, offering bright and sharp images with a nice 3D pop owing to the greater separation of the objective lenses. They are waterproof and fog proof, so can be used in all weather conditions. With a minimum IPD of 50 mm they are ideal for smaller framed faces

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so work perfectly well with kids. Best of all the Raptors can be had for about $100, so represent an excellent bargain in today’s market. Vortex’s lowest cost roof prism binoculars is the Crossfire series, which comprises of four models: 8× and 10×42 and 10× and 12×50. They feature a well-­ designed metal chassis, fully multicoated optics and are both water and fog proof. Many owners are quite pleased with their optical and mechanical performance, but what makes them very attractive to a lot of beginning binocular enthusiasts is the company’s VIP warranty scheme. The Crossfires are good, no-frills, general purpose instruments that will do a good but not outstanding job. Having sampled several of Vortex’s Diamondback HDs I can vouch for their great bang for buck. These are packed full of attractive features including a newly designed HD optical system. Vortex don’t reveal whether they contain ED glass or not though, so the jury is still out on that one! The Diamondbacks went through 3 makeovers before launching their latest HD models, which come in 32 mm, 42 mm, 50 mm and 56 mm aperture classes They have everything the Crossfires have and more including dielectric prism coatings to maximize light transmission, as well as argon purging. They deliver sharp and bright images with lots of contrast. They have very streamlined barrels for excellent gripping and their twist-up eye cups are more than decent. I was particularly impressed by the 10×42 Diamondback HD. Weighing just 604 g, which has got to be one of the lightest models on the market. These are the nearest thing I can think of as ‘do it all’ binoculars. Any drawbacks – a little too much glare when pointed toward the Sun, but most users tolerate this and just get on with their observing. And while Vortex claim to offer the best bang for buck through their HD series, this author has found a few well-designed instruments that serve up noticeably better optical performance with price tags lower than the Diamondback HDs. The next step up in optical quality in the Vortex menu is the Viper HD series. Optically they show better sharpness especially round the edges of the field. They also have better glare control and contrast than the Diamondback HDs and have a better built chassis offering more comfortable eye relief and very high-quality twistup eyecups. Typically they cost about twice as much as the corresponding ­ Diamondback HD. Four models are available: 8× and 10×42 and 10× and 12×50. Vortex’s flagship binocular range is the Razor HD and UHD series. Unlike all of Vortex’s other binocular offerings which are manufactured in China  or the Philippines in the case of the Viper HD, these high-performance binoculars are made in Japan. Vortex Optics has been attempting to create a suitable replacement for their premier binocular (the DLS) for a number of years. Unfortunately, they have struggled to do so until now. Previous iterations of the Vortex Razor binoculars were respectable, but the design and features varied significantly, suggesting that there was no clear vision of what their top-of-the-line optic should be. However, it appears that on their third attempt, they have finally succeeded! Vortex has hit their stride with the Razor HD binocular line. Currently, there are four versions available: 8×42, 10×42, 10×50, and 12×50. The build quality of the binoculars is impressive, as expected from Vortex. The 8×42 model costs $979.99, while the 10×42 model costs $999.99. It is likely that Vortex will expand this line to include a 32-mm line at some point. The new Razor HD binoculars have a simpler roof prism design, which is smaller, sleeker, and more appealing than the previous

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open bridge look. They are also lighter due to their magnesium chassis, which offers greater strength and durability than traditional aluminum frames. The armoring is thinner and clad in a natural green color with gray and black accents and a knubbled texture that provides a secure grip. The barrels are more slender, and the thumb pads are well-placed and shallow, making it comfortable to hold the binoculars even with smaller hands. The Razor HD binoculars are vacuum-sealed and purged with argon, making them waterproof and internally fog proof. The image quality of the new Razor HDs has substantially improved compared to the old Razors. Vortex has not disclosed any changes to the HD glass lens elements, so it’s likely that the coatings have been improved. The coatings include Vortex’s proprietary XR lens coating, which increases light transmission, reduces image-degrading reflections, and improves image brightness. The prisms are BaK4 glass, and Vortex adds a dielectric coating to the prism faces for vivid image color. The prism faces are phase-coated to ensure all wavelengths of visible light are focused to the same plane, resulting in sharper images and more vibrant colors. The ArmorTek coating on the lenses repels oil and salts and reduces dust adhesion, making them easy to clean. Dioptric adjustment is achieved with a twist ring on the upper right barrel, which locks in position when not in use. The diopter adjustment mechanism is a little stiff, but overall it’s a great mechanism. Compared with other binoculars marketed in the $1000 price range, the Vortex Razor HDs do not have a field flattening optical system, but that’s not necessarily a drawback in my opinion. Many binocular enthusiasts, including yours truly, don’t like models with artificially flattened fields and a little natural field curvature is perfectly acceptable. In summary, there is an awful lot to like in the Vortex Razor HD series. You’ll be very hard pressed to see any differences between these instruments and the best offerings from the top European brands. The combination of optical excellence, ergonomic comfort, styling and features is a great value relative to the high-end binoculars offered by many big-name optics companies, which can easily cost twice as much. Personally, I think that once people become aware of just how good they are, we will start to see a lot more of these in the field. And that leads us to Vortex’s new flagship models; the Vortex Razor UHDs. The main upgrade that I can discern is the use of Abbe Koenig prisms for even higher light transmission, but I suspect they have slightly better coatings than the Razor HDs as well. The field of view on the UHDs is noticeably wider too and they have better eye relief than the older HD models. Owners report excellent edge-to-edge clarity. The Razor Ultra HD series comprise 5 models: 8× and 10×42, 10× and 12×50 and a high power 18×56 model. A brief test I conducted with the 8×42 revealed excellent optical performance. Sporting a great 8- degree field of view and an excellent close focus of 1.4 m, the Razor UHD had vanishingly low chromatic aberration, excellent contrast and color rendition. Glare was very well controlled as shown by pointing the binocular near a setting sun. Ergonomically they feel great in the hands, with excellent twist up eye cups, a locking diopter under the right ocular lens. My only gripe with the Razor UHD was its weight- a whopping 913 g! But that seems to be par for the course these days if you want top optical performance. A complex optical system like that found in the Vortex Razor UHD is going to be on the heavy side. You can secure one of these high-end binoculars for retail prices in the range of $1500 for the 42 mm models up to $1700 for the 18×56 Razor UHD.

Chapter 16

GPO Binoculars

The GPO Passion ED 8×32

German Precision Optics (GPO) are new kids on the block. Founded in 2015 by ex-­CEO and Head of Development of Carl Zeiss Sport Optics, Richard Schmidt (who spearheaded the development of Zeiss’ current line of Terra, Conquest and Victory SF binoculars), recruited a world class team of chief executives, scientists and optical engineers from Zeiss, Leica, Swarovski, Meopta and other companies, to bring to market products offering top-drawer optical performance at much more reasonable prices to the consumer. All their products are designed at their © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_16

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headquarters at Inning am Ammersee, in the suburbs of Munich, Germany. Their entry level binoculars – the Passion ED – are assembled in China while their flagship HD series is manufactured in Japan. Once assembled, they are shipped back to Munich, where extensive in-house inspection and quality control takes place, before being dispatched to retailers or individual customers across Europe and North America. GPO now manufacture and sell high-end binoculars, rifle scopes and range finders for the growing sports optics industry. Readers will note that GPO Europe and GPO USA are entirely separate businese. GPO USA is owned by former Zeiss chief executive, Mike Jensen. Although they sell identical products, GPO USA has a superior warranty service. Having sampled almost the entire line of GPO binoculars for myself, I can personally vouch for their excellent quality. The GPO Passion ED line is described as “entry-level premium” by Mike Jensen. The Passion EDs come in four models, 8× and 10×42 and 8× and 10×42. The feature fully multicoated optics using the company’s proprietary treatments, dielectric coatings on the Schmidt-Pechan roof prisms, and ED glass to reduce false color fringing. The most recent Passion ED models have a new Passiondrop hydrophobic coating on the objective lenses which prevents water or oily dirt adhering to the lenses. All these models are fog proof and waterproof too.

A Class Act: the GPO Passion HD 10×42

In regard to mechanical quality, the GPO Passion EDs are very well built. The chassis is fashioned from durable Magnesium alloy which is tough yet light weight. The beautifully machined twist up aluminum eye cups are amongst the very best I’ve encountered. Covered in soft rubber that is very comfortable to rest your eyes

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on, they click into place with great rigidity. I found the eye relief to be just fine on all of the models though some will find them a tad too short when using eyeglasses. The image quality is really good: sharp, high contrast and a nice, big sweet spot. Color tone is warm and vibrant and they control glare very well indeed. For a $500 dollar outlay, they represent really good value for money and come with either a no fault lifetime warranty (in the USA) and a 10 year European warranty if purchased in Europe. If you’ve been impressed with the GPO Passion ED binoculars, then you’ll likely be quite enamored with their flagship Japanese-made Passion HD binoculars, currently available in several formats; 8×42 and 10×42, 8.5×, 10× and 12.5×50. These high-class performers are packed full of premium features including HD optics, the finest multi-layer coatings for excellent contrast and light transmission, a lockable diopter system built into the focuser and GPO’s proprietary Passiondrop hydrophobic coatings on the outer lenses to repel water and grease. My experience with the 10×42 Passion HD was very memorable indeed. The images had excellent contrast, almost no glare even when glassing very close to the Sun and great edge-to-edge sharpness. Light transmission is an impressive 92%! If there was anything to detract from the images it was the occasional detection of chromatic aberration around high contrast targets but it was never enough to distract. As you might expect, these binoculars are quite hefty. The 10×42 Passion HD tipped the scales at 860 g, and the larger models are significantly heavier still. You might think these excellent binoculars would cost a lot but at prices as low as $1000 to $1350, these are really good value for money. GPO also market two larger binoculars with 56 mm aperture, the Passion 8×56 and 10×56. These low light binoculars have Abbe Koenig prisms delivering the brightest images possible – and impressive 91%. Unlike the Passion ED and HD models, they are not equipped with ED glass, as their designers reasoned that in low light conditions such as experienced at dawn or dusk you can’t see chromatic aberration and so special glass isn’t needed. Having said that, my tests on the GPO Passion 8×56 showed that it had very low levels of chromatic aberration. Amazingly, these big and powerful binoculars can be had for about $850. Finally, it would be remiss of me not to mention their innovatively-designed Range guide binoculars in 32 mm and 50 mm apertures that are proving to be quite popular. GPO take great pride in the high-quality accessories they provide with all of their products. You get a beautiful presentation box, an excellent quality padded clamshell case, and a first-rate wide neoprene neck strap with every item. They really are a quality act! Check them out!

Chapter 17

Opticron Binoculars

The Opticron Aurora BGA VHD 8×42

Opticron is a British-based company that specializes in manufacturing binoculars and other optical equipment for birdwatching, hunting, and other outdoor activities. The company was founded in 1970 by David Arnold, an avid birdwatcher who saw a need for high-quality binoculars that were affordable for amateur enthusiasts. In its early years, Opticron was a small company operating out of Arnold’s home. The company focused on importing binoculars from Japan and other countries and 367 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_17

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then selling them under the Opticron brand name. These early binoculars were well-­ regarded for their quality and affordability, and the company quickly developed a loyal following among birdwatchers and other outdoor enthusiasts. As Opticron grew in popularity, the company began to expand its product line and develop its own proprietary binoculars. In the 1980s, Opticron released its first waterproof binoculars, which were designed to withstand the harsh weather conditions often encountered during outdoor activities. This was a major breakthrough for the company, as it allowed Opticron to compete with other major binocular manufacturers like Nikon and Leica. In the 1990s, Opticron continued to innovate with the release of its Imagic and Oregon binocular lines. These binoculars featured highquality optics and ergonomic designs that made them ideal for birdwatching and other outdoor activities. The Imagic binoculars, in particular, were a huge success for Opticron and helped establish the company as a major player in the binocular market. In the 2000s and beyond, Opticron continued to build on its success with new product lines like the DBA and Discovery series. These binoculars featured advanced technologies like phase-corrected prisms and multi-coated lenses that helped deliver crystal-clear images and improved brightness in low-light conditions. Opticron also began to expand its product line beyond binoculars, with the introduction of spotting scopes and other optical equipment. Today, Opticron is a well-respected brand in the world of outdoor optics. The company continues to innovate with new technologies and product lines, and it remains committed to delivering high-quality optics at affordable prices. With a loyal following of outdoor enthusiasts around the world, Opticron is sure to continue its success for many years to come. Starting with their pocket binoculars, Opticron manufacture an extensive range of small ultraportable binoculars that you can take anywhere with you. The Opticron Aspheric 3 WP comes in two flavors; 8×25 and 10×25. It’s predecessor, the Aspheric LE WP was reviewed in the Chap. 3 on pocket binoculars. It has very nice optics, with good sharpness and contrast across nearly the entire field. It folds down into a tiny size that can fit in the palm of one’s hand. It has a built-in lanyard that is a little on the thin side and makes it difficult for it to hang properly on your chest. It’s an enjoyable little glass though, even though both models have a rather restricted field of view (the 8×25, for example, sports a 5.2 degree field). They certainly are elegant little glasses, especially for their modest (~$120 price tags). Indeed, the higher priced Opticron pocket binocular – the BGA T Oasis 8×25 – I tried had far too much glare for my liking, despite its razor sharp Japanese-made optics. It was rather disappointing for a pocket glass with a $250 price tag. Fans of the reverse Porro binocular design will enjoy the Opticron Taigas which come in three magnifications, 8×, 10× and 12×25. Though not nearly as compact as the folding binocular designs, some folk prefer them because they are larger and easier to hand hold. They only have fully coated optics though, so the higher power units will give rather dim images, but they still deliver decent optical performance for a modest investment (~$120). One of the notable and frankly admirable things about Opticron is that they have maintained a good  range of Porro prism binoculars at very decent prices. As I explained earlier in the book, Porro prism binoculars can produce excellent images rivalling the top roof prism models for a small fraction of the price of the latter. The

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Opticron Adventurer T WP Porro prism binocular range offers excellent optical performance at prices that won’t break the bank. The Adventurer T WPs are a fresh look at a great classical optical design. Featuring fully multicoated optics, BaK4 prisms in a stylish aluminum and polycarbonate chassis, they look and feel great in the hands. The central focus wheel is smooth and backlash free and the chassis is covered in a leatherette substrate giving them a rather retro look. All the Adventurers have old school rubber eyecups that can be folded down for use with eyeglasses. Opticron claim that all these models are waterproof, but to what degree remains uncertain. There are several models to choose from: 6.5×32, 8×32, 8× and 10×42, and 10× and 12×50, so something for everyone you might say. These are excellent binoculars in the ~ $100 price class that I would recommend to anyone, especially those on a tight budget. If you like Porro prism binoculars, and like to keep things compact and lightweight, then you ought to check out the Opticron Savanna 6×30 or 8×30 models. Built around the same optical and mechanical qualities found in the Leupold Yosemites and Kowa YFs, these feature a thoroughly modern chassis design, with twist up eyecups offering more comfortable eye relief than the Adventurer T WPs and have nicely padded rubber armoring to ensure a good grip. They are also nitrogen purged and waterproof, so ready to use in any outdoor conditions you’re likely to meet with. What is especially endearing about the Opticron Savannas is their generous IPD range which will allow younger individuals to fully engage with the images. Optically, they’re really good. I thoroughly enjoyed using the 8×30 model, though their fields of view are not quite up there with the widest Porro prism binoculars I’ve used from other manufacturers in the same aperture class. They are real fun to use and are great value for money at under $150. Just when you thought Opticron had exhausted the Porro prism binocular with the Adventurer T WPs and the Savannas, you might be surprised to learn that they offer even more choice through their Imagic TGA WP binoculars. Though a few of these models have been sadly discontinued, Opticron still offer two excellent models to their customers, the 7×50 and 10×50. I tested both of these out in the summer of 2022, and was very impressed with both, ultimately choosing the 10×50 as the better astronomy binocular. They have fully multicoated optics, with the company’s proprietary F coat which really suppresses glare and internal reflections well. Possessing an aluminum chassis covered with excellent rubber armoring makes holding them steady a breeze. They have superb, multi-position twist-up eyepieces offering excellent eye relief so eye glass wearers can comfortably engage with the entire field of view and their right eye diopter system has click stops holding their positions rigidly in place. And even though they are larger-framed binoculars, they tip the scale at just over 800 g making them just a light as a typical full size roof prism binocular. Optically they make a seriously good punch, with excellent light transmission (of the order of 88%), excellent contrast and great near edge-to-edge sharpness. Though the field of view of the 7×50 and 10×50 is 6 degrees and 5.3 degrees, respectively, their excellent sharpness and clarity across the field will endear them to their users. 10×50 is the better option for astronomy, as my tests showed. These excellent binoculars come with a 30-year warranty and certainly are

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built to last. Best of all, they come with very reasonable price tags: $220 or less will secure one. Opticron also market perhaps the most extensive range of quality roof prism binoculars of any current manufacturer. As with other companies, their less expensive offerings are made in their factories in China, while their most expensive models are manufactured in Japan. At the more budget-friendly end of the market, Opticron produce one of their most popular lines of roof prism binoculars in the Discovery PC WP series, which comprises of several models including an 8×32, 7×, 8× and 10×42, as well as larger 8× and 10×50. Apart from the smallest 8×32 compact instrument, all of these models have fully multicoated and phase corrected optics housed inside a sturdy and lightweight Magnesium alloy chassis. Water and fog proof, they have very good eye relief for eye glass wearers. The 42 mm models tip the scales at less than 700 g and even the 50 mm models are not much heavier than 800  g, making them amongst the lightest and most compact models on the market. Owners report sharp and contrasty optics with excellent control of chromatic aberration and an impressive close focus. Another great feature is their unusually small minimum IPD of just 52 mm making them especially suited to those of us how possess smaller faces with more closely spaced eyes. Best of all these models can be had for between $200 and $300. One standout Opticron product for me is the Traveler BGA ED 8×32, a very high-quality compact binocular. Maximizing the portability of this binocular, Opticron’s engineers designed the BGA around a strong but lightweight polycarbonate chassis that keeps their weight down to just 450 g. The BGA features high-­ quality ED glass to minimize color fringing, a whopping 8.2 degree field of view placing a large target area before your eyes. The twist up eye cups lock into place rigidly and have 19 mm of eye relief for comfortable viewing either with or without glasses. Owners report great optical performance with excellent sharpness across most of the field. In short this is one the best compact travel binoculars on the market and retails at about $350 and that’s with a 30-year warranty– a terrific bargain in today’s market by most anyone’s standards. Moving to their flagship models, the Aurora BGA VHD 8× and 10×42. These highly advanced, Japanese-made roof prism binoculars render sensibly perfect optics in a lightweight Magnesium alloy chassis. Packed full of state-of-the-art optical features, such as fully broadband multicoated optics, ED glass, phase corrected roof prisms of the highest quality and field flattening eyepieces, these instruments produce outstanding images, as I was to discover while putting the 8×42 model through its paces. In these tests I was very impressed with its complete lack of glare and almost non-existent chromatic aberration, either on or off axis. Colors are vibrant and contrast is first rate, with excellent edge-to-edge sharpness. Ergonomically, the Aurora BGA VHD is superb, with a locking diopter system built into the focus wheel, multi-position twist-up eye cups offering 20 mm eye relief and a silky-smooth focuser. This is a world class binocular in no uncertain terms! Indeed, it proved to be one of the best instruments this author has personally had the pleasure of experiencing. And with a price tag under $1000, it’s a great buy!

Chapter 18

Meopta Binoculars

The Meopta Optika 8×42. (Image Credit: Meopta Sports Optics)

Meopta Optika is a Czech-based company that has been producing high-quality optical instruments since 1933 and manufacture high quality products for the military, and medical industry, as well as civilian devices for hunters birders and other outdoor enthusiasts. Meopta also produce the optical components for other high-­ end brands too. Their range of binoculars are amongst the best in the market and are widely used by hunters, bird watchers, and outdoor enthusiasts for years. Here, we will explore the features and benefits of Meopta binoculars and why they are a popular choice among nature enthusiasts. Though little known in the UK and USA, Meopta is actually one of the larger sports optics firms in Europe and continue to 371 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_18

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produce binoculars, range finding optics, rifle- and spotting scopes and of the highest optical quality. Indeed, some optics aficionados would argue that Meopta produces some of the world’s best optical products especially when you factor in their competitive prices. One of the key features of Meopta binoculars is their exceptional optical quality. They are built using premium quality optical glass that offers high light transmission, making them ideal for use in low-light conditions. Meopta also uses a proprietary ion-assisted lens coating technology that increases the durability of the lenses while providing excellent image clarity and contrast. This technology allows for maximum light transmission, resulting in bright and clear images. Meopta binoculars also have a robust construction that is built to last. They are made using high-quality materials that can withstand harsh weather conditions and rough handling. Their ergonomic design makes them easy to handle and comfortable to use for long periods of time. Additionally, Meopta binoculars come with a lifetime warranty, which is a testament to their durability and quality. Meopta offers a wide range of binoculars that cater to different needs and preferences. They have compact binoculars that are perfect for travel and outdoor activities, and full-size binoculars that offer a more immersive viewing experience. They also have specialized binoculars for bird watching, hunting, and marine activities. This variety ensures that there is a Meopta binocular for every user and every occasion. Whether you’re looking for a compact binocular for travel or a specialized binocular for bird watching, Meopta has a wide range of binoculars to suit every need and preference. With a lifetime warranty, you can trust that Meopta binoculars are built to last and provide years of reliable use. Starting with their least expensive products, Meopta market a rather nicely made pocket binocular embodied in the MeoSport 8×25. As we all know, carrying standard sized or even compact size binoculars on day-long adventures can be difficult for most people, especially beginners. With an 8×25 specification, the MeoSport has fully multi-coated and phase corrected roof prisms for bright, high-contrast images. It’s also nice and lightweight, tipping the scales at only 390 g so is easy to carry about. Despite their size, they feature a 100% fog proof and waterproof design, which makes them an ideal choice for day-travelers and novices. Additionally, they have a brilliant 18 mm eye relief, which is rare for a pocket-sized binocular. Field of view is not overly large – just 6.3 degrees in fact – but the optical quality is very very good. If you want this nice Czech-made pocket glass, prepare to pay $250 for the privilege. The MeoPro HD binoculars are designed to be affordable but it surprisingly perform at par with premium devices that cost several hundred Euros more. The housing features the same magnesium-alloy material and the rubber armor ensures a comfortable grip, increased durability and protection from accidental damage. Meopta’s MB5501 ion assisted multi-coatings enable objectives to transmit a staggering 99.7% of incident light through a single surface, which is outstanding for budget optics. Also, a second MeoShield coating ensures safety from abrasion, a common problem with exposed glass surfaces. This objectives have fluorite to cut color fringing to an absolute minimum and daylight light transmission of 86%.

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Curiously these high-performance binoculars are available in only three formats – 8×32, 10×42 and a larger 8×56 mm instrument for low light use. The Optika HD series is one the newest addition to the Meopta’s line of binoculars. Unveiled in 2019, these binoculars feature a rugged, lightweight, and shockproof construction, all with ultra-modern ergonomics. The Optika HD is the only binocular series to be partly manufactured in the Philippines, while its assembly is carried out in the Czech Republic. The series feature Meopta’s iconic HD lenses with in-house developed dielectric and phase correction coatings that ensure consistently bright images with unparalleled color-fidelity and superior contrast levels. Like premium models, the housing of Optika HD series binoculars is fashioned from strong but lightweight magnesium alloy and covered in a tough, durable rubber armoring which protects the mechanical and optical systems in case of a hard fall. The Optika HD series is only available in standard objective size of 42 mm along with two magnification options of 8× and 10×. Many hunters have noted their excellent performance in low light conditions, near and after sunset. Indeed, there is more than a grain of truth to the notion that how a binocular performs in poor lighting conditions is the best test for high quality optics. The MeoStar B1 Plus series of binoculars are the company’s highest performing instruments. These instruments have garnered the reputation of one of the finest all-­ round binoculars in the world. The series features multiple lens coatings from MB5501 ion-assisted multi-coatings for an improved light transmittance (88%) to MeoShieldTM which offers excellent resistance to abrasion. The coatings enable MeoStar binoculars to perform in the dimmest of dusk and dawns, especially for hunting enthusiasts. Other features include a locking diopter, excellent rubber armoring, magnesium-alloy housings and an ergonomic design for fatigue-free use for longer periods. These binoculars also feature the Schmidt-Pechan roof prisms to minimize their size and weight, so even with standard sizes, they’re not overly heavy. The MeoStar B1.1 binocular series is available in several magnification and objective variants: including 32, 42, 50 and 56 mm aperture classes.

Chapter 19

Maven Binoculars

The Maven C1 10×42. (Image Credit: Maven Optics)

Maven is a relatively new company in the world of binoculars, having been founded in 2014 by Brendon Weaver and Mike Lilygren, two avid hunters and outdoor enthusiasts. The company is based in Lander, Wyoming, and specializes in manufacturing high-quality binoculars and other optical equipment for hunting, birdwatching, and other outdoor activities. Maven is known for its commitment to quality and craftsmanship, and the company prides itself on using only the best materials and manufacturing techniques for its products. Maven binoculars are designed to be rugged and durable, able to withstand the harsh weather conditions and rough handling often encountered during outdoor activities. One of the unique features of Maven binoculars is the company’s customization options. Customers can choose from a variety of different colors and finishes for the binoculars’ exterior, as well as select the magnification, objective size, and other 375 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_19

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features. This level of customization allows customers to tailor their binoculars to their specific needs and preferences. Maven offers two lines of binoculars, including the B and C series. The B series offers the company’s highest quality instruments, whereas the less expensive C series provides very good all-round performance but not quite reaching the levels of excellence found in the B series. Despite being a relatively new company, Maven has already garnered a strong reputation in the world of outdoor optics. Its binoculars are well-regarded for their quality and performance, and the company has developed a loyal following of hunters, birdwatchers, and other outdoor enthusiasts. Maven is also committed to sustainability, using eco-friendly materials and practices in its manufacturing process. As a result, it’s quickly establishing itself as a major player in the world of binoculars and outdoor optics. With its commitment to quality, customization, and sustainability, Maven is sure to continue its success for many years to come. Their entry-level binoculars comprise the Maven C range, but don’t be fooled, these are still packed with quality optical components, sourced from Japan and China and assembled to their specification in the Philippines. The C2s are their least expensive binocular and come in two models: the 7×28 and the 10×28. These handy compact roof prism binoculars come in Maven’s custom grey and orange polymer chassis. They have fully multicoated optics, phase corrected and dielectrically coated Schmidt Pechan roof prisms and ED glass. The twist-up eye cups give decent eye relief for such small binoculars – 16 mm for the 7×28 and 15 mm for the 10×28. These entry-level Mavens have high light transmission too – of the order of 90%! Furthermore, Maven has added an oil and scratch resistant coating to the outer lenses. Anything not to like? Well, the field of view is rather restricted – just 6.5 degrees for the 7× model and 5 degrees for the 10×. The C1 series is just a scaled-up version of the C2 models and come in three mid-­ sized instruments, 8×42, 10×42 and 12×42. Owners of the Maven C1 8×42 report excellent optics with a slightly warm color tone. The sweet spot extends over about 80% of the field and color correction is apparently excellent. This is a great general-­ purpose binocular that performs well for birding and general nature study. What seems to limit all of the C1s however is there narrow fields – the 8×42 only has a 6.5 degree field – of view which might give the user a tunnel vision like effect if they are used to using binoculars with wider fields. Still for about $400, many feel it’s a very good deal. The last members of the Maven C series comprise the C3 and C4s, which have 50 mm and 56 mm apertures, respectively. Despite being larger binoculars, there isn’t a huge difference in price between them and the C1s. Both the 10×50 and 12×50 retail for just $475 and $500, respectively. The larger 56 mm aperture C4s retail for $700 and $725, respectively. Moving up to the company’s flagship models - the B series - these offer much wider fields of view, better optical quality and a more robust, Magnesium alloy chassis. The B1.2s are an improved version of their original B1 models and are offered in two magnifications; 8×42 and 10×42. Both of these models were introduced in July 2021. Coming in two color schemes, either grey or orange, these

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binoculars use Japanese optical components which are assembled in the US. The B1.2s are slightly smaller framed than the original B1s for improved ergonomic handling. Optically users invariably report excellent image quality both in the center and on the edges. They also have excellent close focus capability to just 1.5 m distance. One very nice feature of the twist up eye cups is that can be screwed off the chassis – handy for cleaning purposes or if they are damaged in field use. Maven cover their binoculars with a lifetime warranty. Are they worth the $1 K price tag? Most would say yes! Maven also offer the same high quality optics in larger models such as the B2 9× and 11×45 – a format that is rather rare in today’s market. Intriguingly, Maven also market the B3 series of 30 mm binocular formats in 6×, 8× and 10×30. Retailing for just over $500, they offer much greater portability than a full-size instrument, tipping the scales at under 500 g, they can be stored in a large pocket. While the 8×30 sports a field of view of 8.2 degrees, the 6×30 is a bit disappointing at just 8.5 degrees. But while many 6×30 models do sport a wider field of view, some have reported that the model is plagued by strong field curvature at the edges of the field which detracts somewhat from the views. If you’re interested in larger aperture binoculars from the Maven B series, you could do worse than check out the B6s in 10× and 12×50 formats for just over $1k or the B5s in 10×, 12×, 15× and 18×56 which retail for about $1500.

Chapter 20

Kowa Binoculars

The Kowa BD 10×56 XD Prominar. (Image Credit: Kowa Sports Optics)

Kowa is a Japanese manufacturer of high-quality optical equipment, including binoculars, spotting scopes, and telescopes. The company was founded in 1894 in Nagoya, Japan, by Tsunejiro Miyazaki, and started as a cotton-spinning company. However, in 1921, the company shifted its focus to optics and began producing lenses for cameras and projectors. By 1952, Kowa had expanded its product line to include binoculars, and the company has been producing high-quality binoculars ever since.

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The early Kowa binoculars were designed for military use, and the company’s reputation for producing high-quality optics quickly spread throughout Japan. In 1954, Kowa introduced its first civilian binoculars, the Kowa 6×30, which quickly became popular among birdwatchers and nature enthusiasts. Over the years, Kowa continued to refine its binoculars, incorporating new technologies and materials to improve their performance and durability. One of Kowa’s most significant contributions to the binocular industry was the introduction of the Prominar line in 1983. The Prominar series featured a high-­ quality fluorite crystal lens, which significantly improved image clarity and color accuracy. The Prominar line quickly gained a reputation for being one of the best binoculars on the market, and they continue to be popular among birdwatchers, hunters, and nature enthusiasts today. In the 1990s, Kowa introduced the Genesis series, which featured a unique prism design that provided a wide field of view and reduced eye strain. The Genesis line quickly became popular among birdwatchers, who appreciated the binoculars’ lightweight design and excellent image quality. In recent years, Kowa has continued to innovate, introducing new technologies such as the XD lens, which provides exceptional image resolution and color accuracy. Kowa’s latest binoculars, the BDII-XD series, features this technology and has received high praise from birdwatchers and nature enthusiasts for their performance and reliability. Today, Kowa is recognized as one of the top binocular manufacturers in the world, and their products are highly sought after by outdoor enthusiasts and professionals alike. The company’s commitment to quality and innovation has earned them a reputation for producing some of the best binoculars on the market, and they continue to be a trusted brand. Kowa market binoculars in all price categories from entry-level right up to world class optics. Let’s start by taking a look at their extensive range of pocket binoculars. Starting with their entry-level, Chinese-made SV II 8× and 10×25, both are dual-hinge folding binoculars that can be taken anywhere at a moment’s notice. Both have phase corrected roof prisms and are treated to Kowa’s proprietary multicoating. Weighing just 260 g, these green rubber armored pocket binoculars offer very decent optics for their modest price tags (~$120), with fields of view of 6.2 and 6.5 degrees, for the 8× and 10× models, respectively. That’s not a misprint by the way. The 10×25 SV II really has a wider field of view. Both models are water- and fog proof. For improved handling, the Kowa BD series, which includes 8× and 10×25 models, offer an alternative offering to the folding dual hinge design of the SV II binoculars in having a larger chassis size. Though it is doubtful that they are true pocket binoculars in the traditional sense of the word. Designed and manufactured in Japan, the BD25s are still a highly compact class binocular. These instruments pack features that are normally only found on much larger models. The fully multi coated lenses and C3 prism coatings, allow for first class light transmission and guarantee for brighter and sharper images. All the internal optics are made from eco glass, making the manufacturing process very environmentally friendly. The dual barrel design makes the binoculars easy and comfortable to hold even for long periods of

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time. They also have a very close focus distance of just 1.8 m. They are 100% waterproof and have also been purged and sealed with dry nitrogen gas to prevent internal fogging. The body is rubber armored to safeguard the internal optics and also provides a firm grip which allows you to hold the binoculars even in wet conditions. These are a good optical step up from the SV IIs hence their higher price tags of about $270. Kowa did not rest on their laurels in creating the BD series of pocket binoculars. Their Genesis Prominar range features 2 Kowa high grade XD objective lenses. This high-resolution ED glass contains large amounts of fluorite crystal – the best material available today for avoiding chromatic aberration & intensifying contrast resulting in a simply stunning view of the natural world. The folded Kowa Genesis Prominar 8×22 binoculars are compact, measuring just 65 mm in width. The binoculars feature a gently curving bridge that supports two hinged barrels made of magnesium alloy. The barrels, covered in non-slip, green rubber armor, house the optics. The ocular and objective sizes are the same, and the small, knurled focusing knob is positioned ergonomically and offers ample grip. At the opposite end of the bridge, there is a second knurled wheel that is narrow and has an incremental scale. This wheel allows for single-eye focusing adjustment but is not lockable. The 8×22 model has an impressive 7.5-degree field of view, while the 10×22 model has a 6-degree field. These high-class pocket glasses don’t come cheap though. Expect to pay in the region of $800 for either. The Genesis Prominar series also includes larger 33 and 44 mm aperture models packed full of state-of-the-art optical technology. Contrast and color correction are excellent  – right up there with the best European brands within their wide sweet spots, but many users report some noticeable softening of the images near the field stops. For some reason or other, these flagship Genesis models from Kowa have not enjoyed the kind of popularity in the west as they seem to do in the Far East. The 8× and 10×33 models tip the scales at under 600 g, while the 8.5× and 10.5×44 models are much heftier at 940 g. The 33 mm models retail for $1100 while the larger 44 mm instruments will set you back $1300. Kowa also produce a couple of lightweight, portable Porro prism models in their YF II series. Two models, the 6× and 8×30 models replace the original YFs. These sport high-quality BaK4 Porro prisms, Kowa’s full multicoating and the outer lenses are treated to the company’s proprietary KR coating that repels water and oily dirt. Both models are also dry nitrogen purged to prevent internal fogging and fully waterproof. The 6×30 sports a field of view of 8 degrees whereas the 8×30 serves up a slightly smaller 7.5 degree. These high quality Porros deliver excellent images, bright, sharp and with high contrast. Unlike older classic Porros, the YFs are equipped with modern twist-up eye cups offering excellent eye relief. And they’re featherlight, tipping the scales at less than 500 g, so you can wear them round your neck all day long. Best of all though, their price won’t break the bank at $120. Kowa also manufacture an extensive range of compact and full-size roof prism binoculars. Starting with their entry level line, embodied in the SV IIs, these instruments have received a makeover from their predecessors in having an all-new green

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rubber armoring unlike the original SV models which had black armoring. Made in the Philippines, the SV IIs come in several sizes, 8× and 10×32, 8× and 10×42 and 10× and 12×50. Having field tested the 8×32 SV II, I can vouch for their excellent ergonomic and optical quality. These instruments have a slightly longer focal length compared with other binoculars and this contributes to the optical quality. Like the YFs, these new SV IIs are fully multicoated and also have the water and oil repelling KR coating on their outer lenses. They contain high quality phase corrected roof prisms for bright and sharp images. The rubber armoring extends well over the objective lenses protecting the optics from rain, dust and stray light. The twist-up eye cups are of very high quality and the soft-rubber covered focus wheel is buttery smooth and super responsive. The SV IIs offer exceptional value for money ranging from $250 for the 32 mm models to just $300 for the 50 mm instruments. In 2015 a new series of binoculars from the Japanese Kowa company was launched under a name of BD XD Prominar. It consisted of seven roof-prisms models: 8×32, 10×32, 8×42, 10×42, 8×56, 10×56 and 12×56. Then in the middle of 2019 Kowa announced that in the fall a new BDII-XD series would hit the shelves, this time without the ‘Prominar’ word in the name. They also decided to change the number of models and some parameters – this time the new series would consist of: 6.5×32, 8×32, 10×32, 8×42, and 10×42 models. The BDII-XD series are engineered to enhance your viewing experience with their comfortable eye relief. They have a sleek, ergonomic design with a specially selected tactile rubber armor layer ensuring easy and comfortable operation all of which enhance your viewing experience. Operation is reportedly flawless. A fluid, responsive focus wheel delivers pin-point accuracy and smooth twist eyecups ensure optimum viewing for both spectacle and non-spectacle wearers. You can tailor the BDII-XD specific to your own viewing requirements with an easy-to-use diopter adjustment system. All the BD II series have high-quality magnesium alloy chassis. Kowa boast of multi-layer coatings covering all elements and C3 and phase-­ correction coatings on Schmidt-Pechan prisms. The outer elements also feature KR hydrophobic layers. The XD objective lens elements have fluorite glass to reduce color fringing to a minimum but what most people buy these for is the superb ergonomics and impressively wide field of view. The 8×32 model, for example has an 8.8-degree field, right up there with the widest available. The lower magnification BD II 6.5×32 has a whopping 10-degree field of view, making it ideal for casual viewing. Many consider this model to be the real jewel in the BDII series, ideal for children and folk with smaller faces. That said, some critical reviewers have noted the excessive field curvature at the edge of the field of these ultra-wide field binoculars. The Kowa BD IIs are very attractively priced at $400–$450. Finally, Kowa also market a range of large aperture binoculars in the Prominar BD XD series, offered in three models with specifications 8×, 10× and 12×56. These Chinese-made binoculars are quite hefty – about 1.15 kilograms – but they can easily be mounted on a tripod or monopod. The XD in the name tells us that they have ED glass which minimizes chromatic aberration. The image is sharp at the center but becomes progressively more blurred near the edges. The field of view

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is not that impressive – just 6.1 degrees for the 8×56 model and 5.5 degrees in the 12×56 unit. The metal focuser takes about two turns to get from closest focus (~3 m) to infinity and the diopter adjustment is made by moving a plastic ring located just ahead of the focus wheel. The Prominar BD XD 56 are a good choice for astronomical viewing on a monopod and the large exit pupil on the 8×56 model is ideal for low light work. These are decent bargains, retailing for about $600.

Chapter 21

Pentax Binoculars

The Pentax 20×60 PCF WP II

Pentax is a well-known brand in the optics industry, producing high-quality cameras, lenses, and binoculars. The company was founded in 1919 in Tokyo, Japan, as Asahi Optical Joint Stock Co. and began producing lenses for cameras. Over time, the company expanded its product line to include binoculars, and today, Pentax binoculars are known for their quality, durability, and performance. Pentax has a wide range of binocular models, from compact and lightweight models to full-size binoculars for birdwatching, hunting, and other outdoor © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_21

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activities. A popular line from Pentax is the S-Series, which features a variety of models that are designed for different outdoor activities. The S-Series includes compact models that are easy to carry, full-size models that are ideal for birdwatching and hunting, and even marine binoculars that are waterproof and fog proof. The S-Series is known for its high-quality optics, including fully multi-coated lenses and phase-corrected prisms, which provide clear and bright images even in low light conditions. Pentax also has a range of high-end binocular models, including the Z-Series and DCF-ED line. The Z-Series features a unique hybrid aspherical lens element, which provides excellent image quality and sharpness, while the DCF-ED series features Extra-low Dispersion glass, which reduces chromatic aberration and provides accurate color reproduction. These binoculars are designed for professional use and are popular among birdwatchers, nature photographers, and other outdoor professionals. In addition to their high-quality optics, Pentax binoculars are also known for their durability and ruggedness. Many of their models feature rubberized armor coatings that provide a secure grip and protect against impacts and scratches. Some models are also waterproof and fog proof, making them ideal for use in wet or humid environments. Whether you are a beginner or a professional outdoor enthusiast, there is a Pentax binocular model that is designed for your specific needs. With a long history of excellence in the optics industry, Pentax is a trusted brand that continues to innovate and provide top-quality binoculars for outdoor enthusiasts around the world. Starting with entry level gear, Pentax market an impressive range of roof, Porro and reverse Porro instruments that offer good value for money. Perhaps the dinkiest is their UD series. Two models exist: a 9×21 and a 10×21 and come in a variety of colored chassis. I tested a black colored 9×21 and was actually quite impressed with the build quality and optical performance. The lenses and prisms are fully multicoated, but no phase correction is made to the roof prisms which cuts down on light grasp and contrast, but for a retail price of about $70 they are very hard to beat. You just have to put up with a lot of plastic. The Pentax AD series market two pocket binoculars with specifications of 8×25 and 10×25. These are folding, dual hinge designs with fully multicoated optics and phase corrected roof prisms. Optically they are quite capable but suffer from rather restrictive fields of view (5.5 and 5.0 degrees for the 8× and 10× models, respectively). Retailing for about £125, they are nicely made pocket binoculars for those who like to carry their optics everywhere. Arguably one of Pentax’s best-selling binoculars is the Papilio II reverse Porro prism binoculars. Coming in two models, a 6.5×21 and 8.5×21, these double up as a regular binocular for viewing distant targets but also as a long-range microscope, capable of getting excellent close-up views of targets as close as 0.5 m. The design of these instruments is intriguing. The focus wheel has an unusually long focus travel. It functions like any other focuser on distant targets but on close objects like butterflies (after which the Papilio is named) or flowers, the objectives turn inward mimicking the tendency of our eyes to cross over when trying to observe an object just a few inches in front of our faces. The eyepieces have twist-up eye cups that

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click firmly into place and the objectives are mounted behind a flat plate of optical glass trated to some anti-reflection coatings to increase light transmission and reduce internal reflections. Having field tested both models, I would say that the 6.5×21 is the more versatile model, offering a nice, wide field of view (7.5 degrees). Optically both models are very capable offering up sharp, high contrast views of their surroundings. Insect lovers will find these great as will artists and photographers to study their subjects in great detail. Any downsides? Not many. Ok, they’re not waterproof or fog proof, but an enterprising owner could get by using them in adverse weather conditions by storing them in a desiccant filled Tupperware container. Some would also say that they are not exactly pocket sized, so despite their specifications they are considerably larger and less compact than a pocket binocular. Regardless of these issues, they sure are a fun binocular to use and own. Indeed, I think all aspiring naturalists should have a Papilio II in his/her collection. The 6.5× Papilio II retails for about $119, while the 8.5× model will set you back $139. Speaking of quirky little optical devices, Pentax recently introduced a multi-­ purpose 4×20 VD binocular. The VD is a three-in-one binocular serving as a 4× magnification conventional binocular with a 10-degree field of view. The barrels can be separated into two independently functioning monoculars; or as a 16× telescope, by connecting the barrels inline. The combination of full multi-coating, phase coating and super-high-reflection dielectric multi-layer coating converge to produce a bright, clear image while reducing flare and ghost images to a minimum. The little Pentax VD has a washable, waterproof construction equivalent to JIS Class 7 (protected against immersion to one meter under the water). While some will no doubt see the Pentax VD as a bit of a niche product or even a gimmick, others will find it wondrously versatile and handy for pursuing all sorts of outdoor activities. As you can imagine, these don’t exactly come cheap at $250. Pentax also market several economically priced full-size Porro prism binoculars in the Jupiter and SP series. The Jupiter series consists of four models in all: 8×40 and 10×50 and 16×50. These have multicoated optics and nice ergonomics with a smooth central focus wheel and grippy black rubber armoring covering the lightweight polycarbonate chassis. These are great entry-level binoculars that will provide the budding birdwatcher or star gazer with a very decent start in the hobby and for about $100 for the largest model, you simply can’t complain about the price. The slightly more expensively priced SP series are classic Porro prism designs with aluminum alloy chassis, an oversized and smoothly operating focus wheel and thick dark grey rubber armoring. The Pentax SPs have been treated to a new fully multicoated antireflection coating ensuring minimal internal reflections and bright, high contrast images. Three models are offered at the time of writing, a 10× and 12×50 and a 20×60. Build quality is excellent, as are the optics. Edge to edge sharpness is impressive thanks to the built-in aspherical lens elements in the eyepieces. One unique feature of these SP binoculars is the lockable focus wheel. Push it forward to lock and backwards to unlock. This author has been using the larger 20×60 SP model for several years now, where it has served as an excellent astronomical binocular for homing in on deep sky objects and also during the day as a great

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alternative to a lower-power solar and spotting scope. The 50 mm models retail for about $200 while the larger 20×60 retails for about $280. Pentax also market an extensive range of mid-sized roof prism binoculars to suit just about everyone’s budget. Starting with their Chinese-made  AD series, these come in a variety of smaller apertures; 9×28, and an open-bridged 9×32. These feature high quality optics and excellent ergonomics as you might expect from Pentax. They have good eye relief, twist up eye cups and are water and fog proof. The 9×32 open bridge binocular is a particular delight. It feels great in the hand, offers a good field of view at 9× – 6.7 degrees – and has very good control of glare and internal reflections. Pentax recently updated their coatings to improve the light transmission for all of their higher end models and you’ll notice this improvement if you compare them to older ones. These handy AD mid-sized instruments can be purchased for about $250. Made in the Philippines Pentax’s SD series are offered in three models, an 8×, 9× and 10×42. Built around a lightweight polycarbonate (640 g) housing, the SD binoculars offer excellent quality twist up eye pieces with 3 intermediate click stops so that anyone can comfortably engage with the full field these instruments serve up. The diopter adjustment is located just ahead of the focus wheel and is adjusted by moving it clockwise or counterclockwise. Like the AD series, they are fully multicoated with high-index phase corrected BaK4 roof prisms. Fully water- and fog proof, they also have Pentax’s proprietary nano-coatings applied to the outer lenses to repel, water, oil, dust and other dirt making the need for cleaning less frequent. The 8×42 offers up a very nice, wide field of 7.5 degrees whilst the 10× model delivers a 6 degree true field. The SD full size binoculars retail for under $300. Incidentally, Pentax also brought out an open bridge version of the SD series which offers improved handling. This 9×42 serves up a field of view of 6.1 degrees and costs just over $300. Pentax’s flagship binocular series is embodied in their Z line of highly advanced roof prism binoculars. A number of models are offered in the Z series including an 8× and 10×43 and larger 50 mm models with (ZD) and without (Z) ED glass. As well as having all the features found in the SD series, these have more durable magnesium alloy chassis and offer superior light transmission and better edge-to-edge sharpness than the former thanks to the incorporation of hybrid aspherical lens elements in the eyepieces. The ZD series all have a locking diopter mechanism built into the base of the right eyepiece. Intriguingly, these more expensive Pentax binoculars don’t offer the buyer an increased field of view though. The 8×43 only serves up a 6.3 degree field while the 10× a mere 6 degrees. But what you do get is extreme ruggedness and capability of functioning flawlessly in all weathers. All the ZDs have ED glass elements to reduce color fringing with the exception of the non­ED 10×50 ZD model. As you’d expect, these don’t come cheap with price tags between $800 and $1000.

Chapter 22

Oberwerk Binoculars

The Oberwerk SE 8×32 (left) & 10×42 ED Porros

Oberwerk is a US-based company that specializes in manufacturing high-quality binoculars for astronomy, birdwatching, and other outdoor activities. The company was founded in 1986 by Kevin Busarow, an avid birdwatcher and amateur astronomer. 389 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_22

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In the early years, Oberwerk focused on selling binoculars for birdwatching. The company’s first product was the 10×50 Mariner, a waterproof binocular that quickly became popular among birdwatchers. Oberwerk continued to develop new binoculars, including the 15×70 Ultra, which was designed for astronomical observations. In 1999, Oberwerk introduced the BT-100XL, a binocular telescope that quickly became one of the company’s flagship products. The BT-100XL featured a 100 mm objective lens and a magnification of 25×, making it an ideal tool for astronomy enthusiasts. With the success of the BT-100XL, Oberwerk began to focus more on development of new binoculars for astronomy. The company introduced several new products, including the 25×100 mm Deluxe and the 20×80 mm Deluxe III. In 2010, Oberwerk announced a partnership with Vixen, a Japanese company that specializes in manufacturing telescopes and other optical instruments. The partnership allowed Oberwerk to expand its product line and offer more advanced binoculars, including the 22×100 mm LX, which was designed for serious astronomers. In recent years, Oberwerk has continued to develop new and innovative binoculars, including the BT-82XL-ED, which features an 82 mm objective lens and extra-­ low dispersion glass for superior color accuracy. The company has also expanded its product line to include tripod mounts, adapters, and other accessories. Overall, Oberwerk has established itself as a leading manufacturer of high-­ quality binoculars for astronomy, birdwatching, and other outdoor activities. The company’s commitment to quality and innovation has made it a favorite among enthusiasts and professionals alike, and its products continue to be among the most respected and sought-after in the industry. Oberwerk first came on my radar over a decade ago when I was leafing through Phil Harrington’s Star Ware back in 2010. In his section on binoculars, Harrington had noted that many of Oberwerk’s early products were gaining momentum with binocular astronomers across North America. His Deluxe II 80, 90 and 100  mm were singled out as being quite excellent. I also learned that even back then, Oberwerk were churning out these large binoculars with full waterproofing and nitrogen purging. And I thought this was only a recent phenomenon, particularly for Porro prism models! Today, Oberwerk markets a variety of excellent large astronomy binoculars as well as smaller instruments for the burgeoning sports optics industry. Over the years they have made incremental improvements to all of their products and the company is now concentrating on upgrading all of their models to ED status. They also produce all-American-made wooden tripods to support their optical wares. Starting with their smaller binoculars, the Oberwerk Sports ED 8× and 10×42 models have received very high praise from the astronomy and birding community alike with their ED objectives, high quality phase and dielectrically coated BaK-4 roof prisms and fully broadband multicoated optics in a lightweight but durable magnesium allow chassis. Owners report bright and sharp images with excellent color correction and contrast. The 8×42 model serves up an impressive 8.1-degree field, whereas the 10×42 model provides a very decent 6.5-degree true field. As you’d expect,

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these Sports ED roof prism binoculars are water proof and nitrogen charged to prevent internal fogging. I love the black and red color combination of the rubber armoring. These make great outdoor companions by day and by night and will set you back $360. One of the great things about Oberwerk is that they still offer a good range of Porro prism binoculars. We’ve already touched on the notable Oberwerk SE series of high-performance ED binoculars which bring this classic design screaming into the twenty-first century. I’ve also discussed the Oberwerk 8×40 Marine, an extremely rugged outdoor instrument with a whopping 8.4-degree field. The Mariner serves as an excellent portable instrument for daytime or nighttime use, although it was especially designed for nautical applications and has rubber armoring to convince you. Perhaps one of the nicer features of the Mariner is that they can be easily self-­ collimated if they happen to get whacked out of alignment and there are plenty of tutorials online to help you with this should they ever require adjusting. Best of all, the 8×40 Oberwerk Mariner retails for just $160 shipped to your doorstep. Oberwerk also cater for the smaller nature explorers of the world in the form of their excellent little Porro prism 6.5×32 LW binocular. Featuring fully broadband multicoated lenses, high quality BaK-4 prisms in a fully waterproof and fog proof lightweight chassis the LW delivers a bright and sharp 8-degree field, plenty enough to take in a lot of the action. The brown colored chassis is covered in a grippy rubber armoring for very effective grasping but best of all the LW has the largest IPD range of any binocular currently on the market – 51 to 74 mm – allowing kids to enjoy the great views. The twist up eye cups provide plenty of eye relief – a full 19.3 mm in fact – and the oversized central focus wheel will enable little fingers to accurately focus on targets. Best of all is the modest price tag. For $84.95, I’d call it one heck of a bargain. Another excellent addition to the Oberwerk line up is their newly introduced Oberwerk SE 8×32. This high-performance binocular was inspired by the legendary Nikon SE. Quite a lot of internet interest was aroused by this binocular, with some individuals openly accusing Oberwerk of intellectual property theft. I didn’t see it that way at all. It was Kevin’s studied attempt at recreating a highly lauded (but long discontinued) Porro prism binocular and upgrading it with an ED objective element, modern twist-up eye cups, waterproof construction and nitrogen filled to prevent internal fogging. Optically, this is an extremely sharpshooter, with excellent color rendition, contrast and showing very little in the way of glare thanks to the exceptionally recessed objective lenses, great baffling and fully broadband coated optics. The aluminum chassis and thick rubber armoring make this a fairly heavy binocular for its specification. My test unit weighed in at 798 g! Edge sharpness is also exceptional. Indeed, it proved sharper in fact than the already excellent Nikon E II 8×30 I tested it against. This is an exceptional binocular for the money. $249.95 gets you the binocular, a very high quality padded carry case made of canvas, snugly fitting rubber rain guard and objective caps, a microfiber cloth and test card. The higher power SEs are worth looking at too, especially for longer range or astronomical work. The 10×42 retails for $279.95 while the 12×50 sells for $319.95.

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The bulk of Oberwerk’s business comes from supplying quality large binoculars to the amateur astronomy community. One of Oberwerk’s recent success stories is the 20×65 ED Deluxe. The 20×65 ED is a relatively new addition to Oberwerk’s range of binoculars. According to Oberwerk, this is their take on the legendary Takahashi 22×60 (discontinued some years ago), which means the 20×65 should provide particularly good correction of chromatic aberration and good edge sharpness. At the same time, the 20×65 Oberwerk features a much wider field of view (3.2 degrees to be precise) than the Takahashi did. The 20×65 is a mid-price instrument that comes into a market of 20× binoculars  – mostly 20×60, 20×70, and 20×80 – with a number of competing products in all price categories (including one from Oberwerk itself, the new 20×70 ED Ultra). The 20×65 Oberwerk is both heavier and larger than almost all other 20× instruments; perhaps that was necessary to achieve the level of optical excellence it achieves. In fact, the Oberwerk exhibits almost no color fringes, whether on axis or towards the edge of the image, better than competing ED binoculars. In addition, sharpness is very good for about 90% of the field. Initial user reviews on the internet confirms this positive impression. The 20×65 is a further example that shows how good China-made binoculars have become now even in the quality segment of the market. Bear in mind that to get the most of this instrument a good solid mount will be required. But you can get hold of the Oberwerk 20×65 ED for just $539.95 and that’s excellent value in today’s market. Oberwerk are also specialists in supplying 100 mm+aperture binoculars. Their flagship models, the BTXL ED and SD ranges offer incredible features for the die hard large binocular enthusiast. These come in apertures from 70 mm right the way up to 125 mm. These beautifully crafted instruments offer excellent color correction thanks to the incorporation of either FK-61 or FCD100 low dispersion optical glass, and nearly flat fields thanks to Oberwerk’s use of excellent wide-angle eyepieces, so images stay sharp nearly right across the field from edge to edge. As we’ve discussed in my chapter on astronomical telescopes, achieving and maintaining accurate collimation on these high-power instruments is always a challenge but Oberwerk pride themselves in ensuring super accurate collimation well above the magnification ranges these instruments are designed to operate at. Owners report stunning high-power views of the night sky and those of us lucky enough to have a home with a great view use these instruments to obtain excellent terrestrial daylight views of wildlife and other natural beauties. Of course, these instruments need to be properly mounted to get the most out of them, but Oberwerk also stock a great range of tripods and mount heads to get you going.

Chapter 23

Leupold Binoculars

Leupold is a leading American brand that produces high-quality optics for hunting, birding, and other outdoor activities. The company has been in business since 1907 and has built a reputation for producing some of the best binoculars on the market. In this chapter, we will discuss the history of Leupold binoculars, their features, and why they are considered one of the best options for outdoor enthusiasts. Leupold began manufacturing binoculars in the 1950s, and since then, they have continued to innovate and produce some of the best optics in the market. The company is known for its rigorous testing and quality control processes, ensuring that every product that leaves its factory is of the highest quality. One of the key features of Leupold binoculars is their optical performance. They use high-quality glass and coatings that enhance the image quality and provide a bright, clear view of the environment. The lenses are coated with a proprietary coating that helps reduce glare and increase contrast, making them ideal for use in low-light conditions. Leupold binoculars are also known for their user-friendly design. They are lightweight, compact, and easy to use, making them ideal for outdoor enthusiasts who need to carry their equipment with them on long hikes or expeditions. They also feature a comfortable grip and are designed to be used with one hand, making them easy to use in the field. Another notable feature of Leupold binoculars is their durability. The company builds its products to withstand harsh outdoor conditions and rough handling. They are made of high-quality materials and come with a lifetime warranty, ensuring that they will last for years to come. Leupold offers a wide range of binoculars, each with its own unique features and specifications. Their entry level roof prism binocular series, the BX-1 McKenzies include 8× and 10×42 models, as well as larger 10× and 12×50. All the BX-1s have fully multicoated optics, phase corrected BaK-4 roof prisms and are fully waterproof and fog proof. One gripe I have with these is their rather restricted field of view. The 8×42 model, for example, only sports a 6.1-degree field of view. Built around a polymer chassis, they have excellent rubber armoring to enable you to 393 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_23

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engage with the action in any weather. These are decent entry-level instruments that will set you up well in whatever hobby you wish to get into. The BX-1s vary in price from about $185 to $230. Incidentally, Leupold also offer two small reverse Porro designs, the BX-1 Rogues in 8×25 and 10×25. These also feature multicoated optics and are also water and fog proof, so good for travel and hiking. Moving up a notch from the BX-1s, Leupold market their BX-2 Alpine HD line of more advanced roof prism binoculars. This series has four models; 8× and 10×42 and 10× and 12×52. These sport wider fields of view than the BX-1s and have better coatings to suppress glare better – Leopold’s Advanced Light Management System. The chassis is made from a lightweight Magnesium alloy for improved durability in extreme weather conditions. The BX-2 Alpine HDs retail in the range of $230 for the 8×42 model and $290 for the 12×52 unit. Leupold’s BX-4 Pro Guide HD takes optical and ergonomic performance to the next level. Manufactured in Japan, these models feature a roof prism design and is built to be durable and lightweight. The binoculars have a high-definition optical system with dielectric coatings, ED glass that provides clear, bright images with excellent color fidelity. The binoculars are available in 8×32, 10×32, 10×42, and 12×50 configurations and have a close focus distance of 2 meters. The larger 42 mm and 50 mm models have an open bridge design for improved handling. Leupold add a special Diamond Coat to their BX-4 Pro HD binoculars, which, they allege, improves light transmission and suppresses glare better. They also have a hydrophobic coating applied to the exterior lenses which makes any water settling on them bead together and run off. Like all Leupold binoculars, the BX-4s are backed up by a limited lifetime warranty. Mind you, these don’t come cheap: expect to pay from $580 for the 32 mm models up to $770 for the 50 mm units. The Leupold BX-5 Santiam binoculars are the company’s flagship products. They come in three different magnifications – 8×, 10×, and 12×. They also feature large objective lenses ranging from 42 to 56 mm, which allows for a wide field of view and enhanced low-light performance. The open-bridge binoculars use a combination of high-quality lenses and coatings to deliver exceptional clarity and contrast. They also feature a phase-coated roof prism system that enhances resolution and image brightness. The Santiam BX-5 binoculars are built to withstand tough outdoor conditions and possess all the features of the BX-4 line and more besides. They are made with a durable magnesium chassis and are filled with nitrogen to prevent fogging. They are also waterproof and shockproof. These state-of-the-art Japanese- made binoculars are designed with a comfortable grip and a large focus wheel that can be easily adjusted even when wearing gloves. They also feature twist-up eyecups with multiple click-stop settings, which allow for comfortable use with or without eyeglasses. All the BX-5 Santiam binoculars come with a variety of additional features, including a built-in tripod adapter, a carrying case, and a lifetime warranty. Prices for these excellent instruments start at $1000 up to $1400 for the larger members of the series.

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In conclusion, Leupold binoculars are a popular choice for outdoor enthusiasts, especially in the USA, who demand the best performance and durability from their optics. With their high-quality optics, durability, and user-friendly design, they are an excellent choice for hunters and birders. The company’s commitment to quality and innovation ensures that Leupold binoculars will continue to be a popular choice for years to come.

Chapter 24

Fujinon Binoculars

The Fujinon FMT-SX 16×70. (Image Credit: Richard Duff)

Fujinon binoculars are a high-quality line of binoculars manufactured by Fujifilm, a Japanese multinational company that is well-known for its cameras, lenses, and other imaging equipment. Fujinon binoculars have been in production for over 60 years, and they are highly regarded by birdwatchers, hunters, astronomers and outdoor enthusiasts worldwide. One of the key features of Fujinon binoculars is their exceptional optical performance. They are equipped with high-quality lenses that provide clear, sharp images even in low light conditions. The lenses are 397 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_24

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coated with Fujinon’s proprietary EBC (Electron Beam Coating) technology, which enhances light transmission and reduces glare, resulting in brighter, more vivid images. Fujinon binoculars are also designed with the user in mind. They are ergonomic and comfortable to hold, with a non-slip rubber coating that provides a secure grip. They come in a range of sizes and magnifications to suit different needs, from compact models for easy portability to larger models with higher magnification for long-­ distance viewing. Another notable feature of Fujinon binoculars is their durability. They are built to withstand tough outdoor conditions, with a rugged, waterproof construction that protects them from moisture and dust. They also come with a limited lifetime warranty, giving users peace of mind that they are investing in a quality product that will last for years to come. Fujinon binoculars are also versatile, with a range of features that make them suitable for a variety of activities. Many models have a close focus feature, allowing users to observe objects at close range. Some models also have image stabilization technology, which reduces hand tremors and provides a more stable image, making them ideal for activities such as boating or viewing from a moving vehicle. In addition to their exceptional performance and durability, Fujinon binoculars are also reasonably priced, making them an excellent value for money. They are a popular choice among enthusiasts who want a high-quality binocular without breaking the bank. The Fujinon Polaris Series of advanced Porro prism binoculars offers six models and are the pinnacle of performance with a reputation of providing outstanding optics at a reasonable cost. The Fujinon Polaris series binoculars offer superb optical performance and value. They deploy Fujinon’s unique Electron Beam Coating (EBC) coating, allowing 95% light transmission. With Fujinon’s built-in field flattener lens, they offer great edge-to-edge sharpness, free of any discernible astigmatism or distortion. All Fujinon binoculars are fully sealed and nitrogen purged to withstand the harshest conditions mother nature can throw at you. Interestingly, the Polaris series all consist of individual focus (IF) eyepieces, which is fine for marine work or astronomy but less desirable for birding, which often requires frequent refocusing on targets at various distances. They are guaranteed to work in temperatures ranging from −20 to+50° C. The FMT-SXs lack rubber armoring while the FMTR-SX have this extra padding. Finally, the FMTRC have an inbuilt compass for worldwide navigation. Fujinon manufacture 7×50, 10×50 and larger 10× and 16×70, offering fields of view of 7.5, 6.5, 5.3 and 4 degrees, respectively. The 7×50 models have 23 mm of eye relief, the 10×50s have 19.8 mm, while the 10× and 16×70 models have 23 mm and 15.5 mm of eye relief, respectively. Make no mistake about it, these represent some of the very best binoculars money can buy. However, the reader should also bear in mind these instruments have considerable weight. For example, the 7×50 FMT-SX tips the scales at 1380 g, so not exactly feather light! Fujinon also markets two binoculars specifically designed for maritime use. The Mariner WP-XL and WPC-XL both sport the exact same 7×50 optics – a beautifully corrected 7-degree field in a lightweight polycarbonate chassis that shaves down the weight to under 1000  g for more manageable handholding. Both models have

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generous 18 mm eye relief and IF eyepieces. The WPC model has a high precision compass built-in with an accuracy of+/−0.5 degrees. Of course, Fujinon are no strangers to the high-tech optics market either. Their line of Techno StabI image stabilized binoculars (discussed in more detail in the next chapter) are perhaps some of the most advanced in the world, offering stabilization over a larger range of angles than other competitors. Several models are offered, 12× and 16×28 as well as a larger 14×40 model. The two smaller models weigh 550 g (16×) and 485 g (12×), whereas the 14×40 tips the scales at a much bulkier 1300 g. But I guess that’s the price you have to pay for packing all that technology inside what is otherwise a fullsize binocular of 40 mm specification. But the good news is that all the Techo StabI binoculars are water proof to 1 m depth for 5 min. The 28 mm models run of a single CR2 lithium-ion battery whereas the larger 14×40 Techno StabI requires 4 AA alkaline batteries to work. In recent years, Fujinon surprised the sports optics world by bringing out a couple of high-performance roof prism binoculars. Their Hyper Clarity series consist of 8 and 10×42 models, which bring quality Japanese optics to the birder and outdoor enthusiast. These high-end roof prism binoculars come with Fujinon’s proprietary EB coatings for super high light transmission as well as their newly designed dielectric and phase coatings on the roof prisms. And the inclusion of ED glass helps reduce chromatic aberration to vanishingly low levels. The 8×42 serves up a very well corrected 8-degree field whereas the higher power 10×42 model delivers a very decent 6.5 degrees. Both models sport state-of-the-art hydrophobic coatings on the outer lenses to repel water and dirt and both have twist up eye cups providing generous eye relief for eye glass wearers. These Japanese made binoculars don’t come cheap but I wouldn’t say they’re overly priced either. You get a lot of binocular for your hard earned dollars. Finally, Fujinon offers world class giant binoculars in the LB150 series. These state-of-the-art instruments offer exceptional high-power astronomical views. And they’re also amongst the most sought-after comet seeking instruments on the planet.

Chapter 25

Bushnell Binoculars

The Bushnell Forge 8×42. (Image Credit: Bushnell Optical)

Bushnell Optical is an American company that specializes in the manufacture and distribution of high-quality optics and imaging equipment. The company was founded in 1948 by David P. Bushnell and his wife, Lenne. The couple started the company in their garage in Pasadena, California, with the aim of producing high-­ performance binoculars that were affordable for the average consumer. Initially, the company focused on producing binoculars for the outdoor and hunting markets. However, it soon expanded its product line to include riflescopes, spotting scopes, and other optical equipment. Over the years, Bushnell has developed a reputation for producing high-quality, reliable products that are both affordable and durable. Some of their earlier instruments are still highly lauded today, such as the Bushnell Custom Compacts and the Rangemasters  – both Japanese made  – with © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_25

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their super-wide angle fields of view. In the 1980s, the company was acquired by Bausch & Lomb, a major American optics company. Under Bausch & Lomb’s ownership, Bushnell continued to expand its product line and market reach. In 2007, Bushnell was acquired by the private equity firm Wind Point Partners, and then in 2013, Bushnell was acquired by another private equity firm, MidOcean Partners. Today, Bushnell continues to be a leading provider of sports optics and imaging equipment, with a product line that includes binoculars, riflescopes, spotting scopes, trail cameras, and more. The company’s products are used by hunters, birdwatchers, hikers, and outdoor enthusiasts around the world. Like most large sports optics companies, Bushnell has adapted its business model to accommodate the changing nature of the consumer market. In this capacity, it offers both entry-level instruments manufactured in China as well as higher end products which are assembled in Japan. Bushnell’s entry level binoculars encompass the H20 series, which consist of many models, from small pocket binoculars to full size instruments with roof prism and Porro prism designs. The H20 series, as their name implies, are all waterproof (IPX7) and fogproof, so can be used in all weather conditions. They feature fully multicoated optics for maximum light transmission. The roof prism models have Bak4 prisms but they’re not phase corrected, some loss of contrast and brightness is to be expected. Their fields of view are also somewhat restricted. The 8×25 H20 for example, has a field of view of only 4.77 degrees, much smaller than any other model the author knows of. The 8×42 H20 only provides a 5.8-degree true field. Anyone used to looking through binoculars with average sized fields may succumb to severe tunnel vision. Still, you can’t expect too much considering their very low asking prices – just $44.99 for the 8×25 and $99 for the 8×42 roof prism model. You’re probably far better off going with the Porro prism models from this series as they don’t require all that much technology to deliver good images and their fields of view are wider to boot. For example, the Bushnell 8×42 Porro H20 model sports a much more decent 6.5-degree field and its retails for just $84.99. Bushnell’s mid-range binoculars encompass the Engage EDX series which feature much more advanced features than their lower tier products including ED glass, phase corrected roof prisms and dielectric coatings for improved brightness, resolution and color correction. The 8×42 has a wide (8.1 degree) field of view, making it a rather nice birding binocular. Bushnell‘s latest EXO Barrier Protection coating – said to be the best protective lens coating technology the company has ever developed – has been applied to external glass surfaces to repel water, debris, oil and fog, as well as helping to prevent scratches. If you’re after more magnification there is also a 10×42 EDX. These instruments retail for about $350. Bushnell’s new flagship range of binoculars – the Forge 8× and 10×42 – have all the features of the EDX range but has a more advanced open bridge chassis, better color correction, and a locking right eye diopter. The twist up eyecups are fashioned from machined aluminum and provide excellent eye relief (19 mm). They also have nicely made built-in objective lens covers. Reviews of the Bushnell Forge

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binoculars are invariably positive, but some have noted that they are very much on the heavy side, tipping the scales at about 877 g. That said, the Forge models have excellent close focus at 1.6 m, so great for viewing butterflies, flowers and insects at close range. As you’d expect from Bushnell the Forge binoculars have an IPX7 rated waterproofing and are also nitrogen purged to prevent internal fogging in cold weather. These high performance instruments retail for about $459.99 and come with Bushnell’s excellent lifetime warranty.

Chapter 26

Popular Binocular Accessories

Just like telescopes, binoculars come with a wide variety of accessories that can further enhance your visual and ergonomic experiences. This chapter will explore the most commonly used and arguably, the most important accessories used by binocular enthusiasts.

Zeiss Lens Wipes and Microfiber Cloths

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I take one of these whenever I’m out for an extended length of time with my binoculars. Sometimes you can find yourself moving through difficult terrain like dense scrub and your optics can sometimes pick up water drops which dry into spots. And on windy days, wind-blown matter may accidentally get on your lenses. If you stop to eat a snack, crumbs and other debris may accidently settle on your optics, so these wipes are great for cleaning your optics while in the field. Why Zeiss wipes? They’re the best, period. After blowing away any large deposits on the lenses, I open one of these individually packed wipes and apply circular strokes to the lenses to remove any remaining crud. I also like how they do not leave any residue on the lenses – just clean, transparent optics. You need to be quick though; the fluid-soaked wipe evaporates away very quickly. If you’re not up to bringing along some Zeiss lens wipes with you then you should consider carrying a microfiber lens cleaning cloth with your binoculars. They come in very handy if you have to clean your optics in an emergency. Because the fibers are very fine, they will not scratch your optics. Just keep it clean inside its plastic sleeve.

Neck Straps Very few binocular enthusiasts pay close attention to the quality of the neck strap they use to carry their binoculars. All too often many budget binoculars will come with neck straps that are only so-so quality wise and are often inappropriately matched to the weight of the binocular. Heavier instruments require stronger and wider neck straps to effectively counteract neck strain. Using too thin a neck strap will also cause chaffing. In general, try to use the strongest and wide-rimmed neck strap that is comfortable to use with your binoculars. That little extra support results in much greater comfort and less neck fatigue if you intend on using them for prolonged periods of time in the great outdoors. Always examine the lugs of your strap to ensure it is properly fastened to the binocular. I’ve discovered some can come loose if not monitored occasionally. Older straps can begin to fray and thus are more prone to snapping. Indeed, on one occasion, one 8×32 glass I was testing had one lug come completely loose so much so that it became detached from the binocular. Luckily, I was able to catch the instrument before it hit the ground. Phew!

Rain Guards and Objective Lens Covers

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BlueCabi neck straps provide excellent support for your binoculars

I can personally recommend BlueCabi neck straps. They are well made and provide excellent support for my heavier binoculars. The wide neoprene neck support makes carrying heavier equipment much easier to deal with. They’re also available in a range of colors if that means something to you.

Rain Guards and Objective Lens Covers Imagine you’re out on a walk through the countryside; your adventure starts out well; conditions are sunny and the light is good and strong, but then some clouds appear on the horizon, and as the minutes pass, the sky darkens and the heavens open. You’re carrying a large binocular round your neck, so there’s no way it’ll fit in your jacket pocket and you’ve neglected to bring something to cover the lenses. You can’t duck for cover because there are no trees or hedgerows to huddle under. Your binoculars are going to get soaked. Or imagine exploring a dry and dusty environment where the winds get up and blow fine sand and dust onto your expensive optics. Without protection, some of that dust ends up on your binocular lenses. These scenarios, which are not at all uncommonly experienced, serve to illustrate why you need to carry a protective rain guard for your optics. Thankfully many binoculars these days come with rubber structures that fit onto your eye lenses, but the quality can vary a lot. Many of the cheaper rain guards are made from plastic but rubber is a much better material to use. Plastic rain guards can actually scrape away at the rubber on your eye cups and in the long term can cause significant damage to them. Because rubber is softer and more flexible, far less damage is done in the long term. The rain guard often has the provision of being tethered to the neck strap. This is a practical solution to always keep it with you.

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That said, I personally never tether anything to my binoculars as I don’t like having dangly bits anywhere near my optics, but I still carry one, even when the chances of rain are minimal. Rain guards should also be food guards. Many birders and hunters bring lunch with them and end up eating snacks while their binoculars are still round their necks. And if you thought water is not good for your lenses, food landing on your optics can potentially be far more harmful. I’ve personally encountered binoculars with breadcrumbs, mayonnaise, tomato ketchup, or butter find their way onto ocular lenses. If that does happen, use fresh water from a stream or a river to wash it off gently. Your skin acts as a very effective cleansing tool in emergencies like this. Circular strokes work best. Then allow it to air dry. That should keep you observing. Once you’re home and have access to proper lens cleaning fluid you can do a more thorough cleaning job using a fine microfiber lens cleaning cloth. Better still, bring a Zeiss lens wipe with you. They work great to clean up your optics to allow you to re-engage with your subjects more quickly. Objective lens covers are popular with many binocular enthusiasts. These are either built into to the end of the barrels or have a rubber ring that enables the user to mount them on the end of the binocular barrels. Personally, I never see much point in using these as even when the binocular is not in use, they are still hanging around your neck and pointed straight down so avoiding getting wet. In addition, these add more weight to your load and anywhere you can shave off an ounce or two is a good idea, especially if you are using the binoculars for prolonged periods. Others will no doubt disagree with me here. They will claim that they are excellent for protecting the objectives from other things such as wind-blown dust and sand. For storage purposes they also come in handy as they will protect your optics if the instrument is being stored inside a case for long periods of time.

Winged Eyecups and Glare Suppressing Devices

Winged eyecups protect against the encroach of stray or peripheral light

Antifogging Spray

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Sometimes, when you’re out and about with your binocular, peripheral light or strong illumination emanating from behind your line of sight can introduce glare or unwanted glints or reflections from the eyepiece lenses which can be annoying and in the worse cases, reduce the contrast of whatever targets you may be viewing. That’s why some binocular users employ special winged rubber eye cups that have upraised shielding to black off peripheral light and so reduce glare and the unwanted effects of peripheral light. They simply attach to your existing eyecups and can be rotated into any position you personally favor. Most of the main binocular manufacturers sell their own versions of these in a variety of different sizes to match the specifications of your instrument. You can also buy them from companies like Field Optics Research which trade on Amazon. Do they work? Yes, to some degree. But I’ve found that they can be hard to engage with, as you must push your eye sockets deeply into the ocular lenses to make the most use of them. I’ve found that they can slow you down a lot, especially if you frequently bring the binocular to your eyes. As a result, you’ll probably swear by them or at them! Bigger binoculars really benefit from peripheral shielding even more than smaller instruments, especially if they’re being used in bright sunlight or at night in the presence of strong light pollution. Products such as the Alpine Bino Bandit have proved very popular with many binocular enthusiasts. These fit over the eye cups of your binocular and provide an effective shade by creating a miniature awning that cuts out peripheral light and can make smaller binoculars appear to give brighter images as a result. They also block off peripheral wind and rain that can interfere with your glassing. The Bino Bandit can also be folded over the eye cups and clipped closed so acting as a makeshift rain guard. It can also be folded downwards so that it can fit over your binocular carry case if need be.

Antifogging Spray Zeiss don’t just market great lens wipes, they also market a new antifogging spray if you happen to be working in a high humidity environment or if your binoculars don’t have hydrophobic coatings applied to the outer lenses. Simply spray some of the fluid onto the supplied microfiber cloth and then apply to the lenses with circular strokes. It works well. If you apply some to the objectives of a binocular, it will quickly disperse any fog or condensation that happens to form on it in seconds. Any downsides? Well, it doesn’t last very long – only a few days – so needs to be applied regularly to stop your lenses fogging up.

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Defense against lens fogging: Zeis AntiFog Spray

A Lightweight Monocular Have you ever found yourself in this predicament? You’re out glassing and hit on an interesting or unusual target in the distance. The 8× glass you’re carrying doesn’t quite do you justice as the target is located just a bit too far away to see any details. You could do with a quick magnification boost. That’s why I find having a lightweight monocular very handy. I have a Barr & Stroud 15×50 Sprite Plus monocular. Weighing just 440 g, it features fully multicoated optics, phase corrected BaK4 roof prisms and is both water and fog proof. This nifty little instrument fits in any pocket and can be deployed in seconds without the need for a stabilizing tripod. The Sprite Plus has a decent sized exit pupil despite its high power – 3.33 mm – which is a close match to my favorite birding glass – the Nikon E II 8×30 with its 3.75 mm exit pupils – so there is little in the way of image dimming compared with the images served up by my binocular. If you need some extra stability, I usually steady the monocular on a fence post or tree trunk. Works great!

Monopods and Tripods

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Monopods and Tripods Monopods and tripods are essential accessories for mounting binoculars and stabilizing the viewing experience. While monopods and tripods serve the same basic purpose, there are some key differences between the two. A monopod is a single-­ legged support structure that can be used to stabilize a binocular. It’s similar to a tripod, but it has only one leg instead of three. Monopods are typically lightweight and easy to carry, making them a popular choice for outdoor enthusiasts who need to move around frequently. Monopods are also relatively inexpensive compared to tripods, making them a good option for those on a budget.

The Oberwerk Series 2000 Monopod with grip action ball head. (Image Credit: Oberwerk)

Monopods can be used for both seated and standing observations but few are sufficiently long to enable you to carry out high altitude observations comfortably. One exception is the Oberwerk 2000 Monopod which extends to 78 inches in length and so can easily allow people well over 6 feet tall to observe high altitude objects in the sky. It comes equipped with a strong grip action ball head so that you can use binoculars up to 80 mm in diameter with loads as heavy as 4 kilograms. I’d say it’s a bargain at just over $100. The addition of a trigger grip ball head makes the monopod much more versatile as it removes the need to constantly adjust the tension by tightening or loosening a screw.

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26  Popular Binocular Accessories

That said, I personally find observing high altitude objects using a monopod-­ mounted binocular to be uncomfortable, much preferring seated observing or reclining on a zero-gravity chair.

An ordinary photographic tripod suffices for most terrestrial binocular viewing

Tripods, on the other hand, are three-legged support structures that provide a stable and secure base for a binocular. They are typically larger and heavier than monopods, making them more suitable for stationary use. Tripods come in a variety of sizes and designs, ranging from small and lightweight models for travel to large and sturdy models for professional use. When selecting a tripod or monopod for use with binoculars, it is important to consider several factors, such as weight, height, stability, and portability. The weight of the support structure should be appropriate for the weight of the binoculars and other accessories being used. The height of the tripod or monopod should be adjustable to accommodate different users and viewing positions. Be sure to select a tripod that can accommodate a good pan handle in order to move your optics around easily.

Monopods and Tripods

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The SnapZoom Universal Binocular Mount

The stability of the support structure should be sufficient to keep the binoculars steady during use, and the portability of the support structure should be suitable for the intended use, whether it be hiking, bird watching, or other activities. A lightweight photographic tripod is fine to use for terrestrial observations as you’ll not need to tilt the binocular very much, but they simply don’t work well for astronomical observations as the legs always get in the way making it very difficult to get comfortable behind the eyepieces. You’ll need to mount the binocular as securely as you can to the tripod though, so will need a suitable platform to place the instrument on. I highly recommend the Snapzoom Universal Binocular Mount. It fits any photographic tripod and is great for quickly mounting any binocular. The binocular is held in place by a loop that goes over the binocular and is secured by Velcro.

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The Oberwerk PM2 Parallelogram Mount. (Image Credit: Oberwerk)

Larger binoculars used for astronomy require much more robust mounts. One of the best solutions I’ve seen is embodied in the parallelogram mount. The first thing this type of mount does is move the observer well away from the supporting tripod. Secondly, they allow you to easily change the height of the binocular to allow a number of individuals with different standing heights to comfortably view through the binoculars. Thirdly, parallelogram mounts enable you to observe up to a quarter of the night sky without having to move. They do have a number of disadvantages though. For one thing they are heavy and cumbersome to erect and the long moment arm can take longer to settle down, especially if you encounter windy conditions. Large and heavy binoculars may require the installation of counterweights which increase the hassle of setting them up. Despite these drawbacks, they have proven quite popular with binocular astronomers who either purchase them complete or are constructed from a DIY project. Perhaps one of the best is Oberwerk’s PM2 parallelogram mount. Fashioned from maple wood, stainless steel, and aluminum, it

Binocular Harnesses

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mates seamlessly with the company’s heavy-duty TR3 maple wood (or Walnut) tripod. Owners report excellent, hassle-free observing, whether sitting or standing. The parallelogram mounts retails for $679.95 while the tripod will set you back an additional $449.95. For much more on binocular mounting, I’d recommend Stephen Tonkin’s book, Binocular Astronomy, which goes into quite a bit of depth concerning all of the types of mounts you can consider before embarking on a purchase or a DIY project.

Binocular Harnesses If you’re binocular adventures carry you out for many hours on end, and if you like taking along a full-size instrument, then a binocular harness might be a very wise choice. While a high-quality padded neck strap can do a lot to lighten the load, a binocular harnesses is often a better choice. Why? Because it distributes the weight of the binocular around both your shoulders and your back. A strap on the other hand distributes the weight of the binocular only around your neck. Granted, most binoculars are not that heavy but if you find yourself out birding or hunting for several hours many times in every week, your poor neck muscles will feel the strain. The other reason for wearing a harness is it greatly reduces the movement of your binocular as you move around. Imagine climbing a hill or negotiating a stone wall. If you just use a strap, the binocular will end up swinging to and fro and that can be a problem if you want to keep your binoculars perfectly collimated for as long as possible. On one occasion, one of my binoculars ended up whacking me in the knee. I ended up having a small bruise from the impact but it also was enough to offset the collimation on a budget Porro the strap was attached to. With a harness, these accidental events are greatly minimized. Many outdoor and sports optics dealers sell various kinds of harness. I would advise trying one on with your binocular before making a purchase. Some companies like Vortex supply harnesses that can attach the binocular and its case securely on your chest- very handy if you’re ducking a rain shower or protecting your optics from wind-blown dust etc.

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Notebooks and Journals

As a keen naturalist, a good quality ledger is an absolute must have

I’ve said it before and I’ll say it again – a naturalist without a notebook has no past! Note making is an essential activity for anyone wanting to accurately record their experiences and can prove invaluable at some future time when a detail previously considered superfluous suddenly becomes apparent in the present. I keep a ledger with me in my rucksack when I’m out for any extended length of time. I usually do all of my note writing during or shortly after observing a target of interest. I use a note pad covered in a leather cover which can be replaced once it’s filled. The ledger also has a provision to store a pen or pencil away at the side, so I don’t need to rush to find it when I’m writing up. The other reason why I like taking notes is that they’re very interesting to look back over at some later time. Indeed, note making can bring you right back to a time or a place to jog your memories of some of the fondest moments you enjoyed in the field. As well as taking notes on my subjects, I generally include the date and approximate time of day I recorded it on, not to mention details about the weather conditions that day.

Chapter 27

Testing Binoculars: Notes from the Field

Binoculars are like shoes, one size doesn’t fit all. That’s why they are best tried before you buy. But what sorts of tests should you do to make sure you’ve found the right instrument for you? This chapter aims to answer this question. Accordingly, we’ll be taking a closer look at the things you can do to test the mechanical and optical quality of a binocular to make sure it’s right for you.

Ergonomics When you first take hold of a binocular, the first thing to check is that you can get the right interpupillary distance (IPD) to suit your eyes. The central hinge should be quite stiff but still move smoothly when some force is applied to it. The hinge should be moved enough to get the eye cups perfectly centered on your eye pupils, such that a single image is seen when you look through the eyepieces. Take the binocular away from and then back to your eyes to make sure the image is stably held. Another useful test is to pan the binoculars across an extended target in the distance to test for blackouts. Ideally you should know your IPD prior to buying the binocular. Most optics companies state the IPD range in the specifications, so you should get a good idea if they fit your eyes correctly. Hold the binocular in your hands. Does it feel good? Can you obtain a good grip on the rubber armoring? Can you wrap your fingers around the barrels to access to focus wheel while looking through the binocular? Next, examine the focus wheel. It should rotate smoothly and consistently in both directions all the way through its travel. Do this a number of times to see if you pick up any free play or backlash in the movement. If you’re purchasing a binocular for the purposes of birding, you’ll likely fare better with a fast-focusing speed. Fast focusers don’t need much in the way of rotation to go from closest focus to infinity. If you are buying a binocular for

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_27

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hunting, a slower focus is often preferable, taking longer to go from one extreme of travel to the other. Next examine the eye cups. If they are the twist-up variety, do they twist up and down smoothly? Do they lock in place at every detent? Do the eyecups sit comfortably on your eye sockets? If you wear glasses, you’ll likely need to use the eyecups in their fully retracted position. Can you see the entire field of view while using your glasses? Next, test the diopter system. Usually this is found under the right ocular lens. Does it rotate smoothly but firmly i.e., with a fair degree of tension? Next, you’ll need to make sure you can adjust the diopter compensation for your particular eyes. Select an object away in the middle distance. Ideally it ought to have writing on it like a road sign or car number plate. Cover the right objective with its cap and looking through the binocular with both eyes open, use the central focus wheel to bring your target into the sharpest focus you can achieve. Next, cover the left objective and look through the binocular once again using both eyes. This time don’t touch the central focus wheel but instead rotate the right eye diopter until the target comes into sharpest focus. Now remove the cap from the left objective and look at the target again through the binocular. It should be tack sharp in both eyes. That’s it, your binocular has been correctly adjusted for your eyes.

Examining the Exit Pupil Point the binocular at a soft artificial light source or the sky overhead on a bright day. Examine the shaft of light emerging from the eye pupils. Are they round? If so, that’s good news. Sometimes you might notice that one or more of the pupils departs somewhat from circularity, where the eye pupil is somewhat truncated. In most situations a small amount of truncation is tolerable but do bear in mind that exit pupil truncation cuts the amount of light reaching your eyes, reducing the effective aperture of your binocular.

Examining the Exit Pupil

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An example of a very good exit pupil appearance

You can also use the pupils to verify whether your binoculars have BK7 prisms or BaK4. Lower quality BK7 prisms will often (but not always) appear diamond-­ shaped and  show shaded or blurred edges when you perform the same tests, as opposed to higher quality BaK4 prisms which should present perfectly round pupils which are evenly illuminated from edge to edge. The exit pupils can also be used to verify the magnification of the binocular. Since the exit pupil is calculated by dividing the diameter of the objectives by the magnification, measuring the size of the exit pupils also provides a means of checking the magnification. For example, suppose you have a 8×32 binocular and find that while the aperture is accurate, the exit pupil turns out to be 3.9 mm instead of 4 mm, then the real magnification will be 32/3.9 = 8.2×. Ideally the pupils should be surrounded by perfect darkness – a sure sign that there are no light leaks or interference from reflected light within the barrels. It’s actually not very common, in my experience at least, to see pupils that are surrounded by perfect darkness. Often, I’ve found one or more ‘false’ pupils – a bright shaft of light outside the exit pupil. This is quite often seen in binoculars sporting Abbe Koenig prisms but unless it’s located very close to the true exit pupil, it won’t affect the views appreciably in my experience. Now, depending on how close these false pupils are to the real pupil, they can introduce varying amounts of glare in the image. I’ve noted this effect in some binoculars I’ve tested. During bright sunny conditions the exit pupils of your eyes shrink to reduce the amount of light entering the eye and you notice little or no glare but go out at dusk when your exit pupils

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27  Testing Binoculars: Notes from the Field

increase in size and may now overlap with the false pupil showing you unwanted glare. This is far more likely to occur in models having intrinsically small exit pupils like pocket and compact binoculars.

Testing for Internal Reflections To see how well your new binocular responds to an intensely bright light source, use a torch adjusted to its brightest setting. Set the torch a few meters away from the binocular, but not so close that you can’t focus on it sharply. Now turn on the light source – I use my iPhone torch light at its brightest setting – and look through the binoculars. Do you see internal reflections where the light bounces off one or more surfaces in the optical train? If so, are they bright? How many are there? The reader will note that this is quite a demanding test on your optics. It will tell you something about how your binocular will behave if it is pointed toward a bright light source like the Moon or a streetlamp after dark or how the instrument might behave when pointed toward a strongly backlit target in the vicinity of a setting sun for example. Most binoculars – even very good ones – will show some reflections in this test, but if they are small and quite well controlled you have nothing to worry about. Can you detect any diffraction spikes emanating from the light source? This is quite commonly seen on roof prism binoculars but never in Porro prism designs. For example, my little Zeiss Terra Pocket 8×25 binocular shows up a prominent diffraction spike on bright light sources like streetlamps but is quite passible when viewing the Moon. Another thing to check for is diffused light or glare immediately around the beam. This is a good test to see how your binocular will handle glare during daylight activities. The worse it is the lower the overall contrast of the images it will generate.

Collimation Tests No matter how well made the optics are in your binoculars, they will be next to useless if the barrels are not collimated. This simply means that the two images from the barrels of your binocular merge to create a single image with one-to-one correspondence. The most commonly reported phenomenon that results from mis-­ collimation is a double image, where your brain just can’t merge the two images properly. In my experience when you struggle to get a good focus or are constantly adjusting the diopter ring, a collimation issue may lie at the heart of the problem. Perhaps the simplest way to check collimation is to select a terrestrial object at least 100 yards away. Now cover one of the objectives with your palm whilst keeping both eyes open. Now quickly remove your palm from the objective. If there is any misalignment, two distinct images will be seen for an instant before your brain begins to snap the images together.

Tests for Distortion

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What a perfectly collimated binocular looks like

Another useful procedure to test collimation involves using the stars. Select a bright star in the sky and focus it so that it’s a sharp pinpoint of light. Now, while continuing to look through the binocular, rotate the diopter ring to the farthest it will go in its travel. What you will see if the binocular is properly collimated is a bright star inside or on a defocused anulus of light. If the star appears outside or disconnected to the anulus you have a mis-collimated binocular. It’s important to move the star around the field to see if the defocused and focused star remain associated with each other. I’ve tested some units which looked reasonably well collimated when the star was kept in the center of the field, but once moved to the top or bottom of the field, or from one edge of field to the other, the images became detached indicating a collimation issue. Mis-collimation will make your binocular glassing hell on earth, by causing headaches after any prolonged length of time in the field.

Tests for Distortion Distortion is caused by variations in the magnification of the image depending on the distance from the optical axis. There are two types of distortion: positive and negative. For a single lens image distortion, irrespective of image visibility, increases in proportion to the incident angle cubed, so the further an object is placed from the

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center of the image, the greater the distortion. For complex optical systems such as binoculars, the story is far more complicated and in fact, most of the distortion is generated by the eyepieces. Positive distortion is often referred to as pin cushioning and is seen when a vertically erected target like a drainpipe or telephone pole bends away from the center, while negative distortion, also known as barrel distortion, bends towards the center of the image. Pincushion distortion occurs when magnification increases toward the edges, while barrel distortion results from decreased magnification as the subject is moved away from the center. Perhaps the most infamous of all distortion profiles is the so-called ‘moustache distortion’ where the center of the image manifests pincushion distortion, crossing over to barrel distortion at the edge of the field.

Tests for Chromatic Aberration Chromatic Aberration (CA) results in different colors of light being focused at different positions, resulting in color fringing – usually blue or purple – around high contrast objects. Because most binoculars operate at low magnifications, the amount of chromatic aberration you see is usually very minimal, but some folks are more sensitive to it than others. In general, the larger the aperture and the higher the magnifications used, the greater the effects of color fringing become. In addition, CA can derive from the objective lenses and also from the eyepieces. There are in fact two types of chromatic aberration: longitudinal/axial and lateral. Longitudinal color fringing occurs in the center of the field, while lateral chromatic aberration appears off axis, in the outer part of the field of view. The latter is caused by the focus point of the different colors appearing at different positions on the same plane. To correct for color fringing some binoculars incorporate extra low dispersion (ED) glass which has the effect of tightening up the focus of two or more colors to reduce fringing. This effect also improves the contrast in the images, though in my experience, these effects can be quite subtle. To test for CA point your binocular at the branches of some trees or a telephone pole against a bright overcast sky. If your binocular has CA it will show up some blue/purple fringing at the edges of the branches. Many binoculars, even those without ED glass can show very little CA on axis but if the target is moved off axis the effects of lateral CA become apparent. Bear in mind that small binoculars will likely show less CA than larger ones, so don’t be surprised if you can’t see any in your small pocket glass but see significantly more in larger aperture instruments simply because you’re gathering extra light, and the brighter images help you see this CA better.

Spherical Aberration

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Chromatic aberration: Because the refractive index (degree of bending) of light varies with wavelength, different colors are focused at different points along the optical axis resulting in color fringing i.e. chromatic aberration. (Image Credit: Wikipedia)

Spherical Aberration Spherical aberration is present when the outer parts of a lens do not bring light rays into the same focus as the central part. Images formed by the lens at large apertures are therefore unsharp but get sharper at smaller apertures. If the peripheral rays are brought to a closer focus than the near-axial rays, the optic is said to be undercorrected. Conversely, if the same axial rays are brought to a more distant focus the system is said to be overcorrected. Spherical aberration scales with the cube of aperture and is independent of angular displacement from the center. Strong spherical aberration is quite uncommon in binoculars. By stopping down the lens diameter you can reduce the effects of spherical aberration. Moderate spherical aberration results in a softening in the focus of the image, in such a way that you find yourself trying to find the best focus constantly. Binoculars having the best spherical correction snap to focus with no ambiguity. You’re either in focus or you’re not.

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Spherical aberration: the top image shows a perfect lens focusing all rays at the same point. The bottom image shows spherical aberration, where rays coming from different parts of the lens are focused at different points. (Image Credit: Wikipedia)

Field Curvature This aberration occurs when the light rays coming from a point apart from the optical axis are focused at one point. But this point may not always be included in the vertical plane to the optical axis. The result is called curvature of field. With a lens having this aberration, even if you focus around the center of the field, the periphery of the field appears out of focus and vice versa. It can cause very bad effects especially on wide-field-type binoculars, especially the less expensive models. Field curvature is easy to recognize because it’s the only aberration that can be focused out. To see its effects more clearly, center a bright star in the binocular and then proceed to move it to the edge of the field. Usually, the star will bloat in size as it becomes more and more out of focus. Now, move the focus wheel to see if a touch of re-focusing diminishes the size of the star. If you can focus the star down to a nice tight pinpoint again, you’re seeing the effects of field curvature. If you can’t focus it out, the aberration is most likely attributed to something else like coma or astigmatism or a combination of both.

Astigmatism

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Field curvature: the image “plane” (the arc) deviates from a flat surface (the vertical line). (Image Credit: Wikipedia)

Coma Comatic aberration results when each cone of light focuses on different planes along the optical axis. While spherical aberration is caused by a difference in focus point, coma is caused by a difference in magnification. A point source such as a star tails toward the exterior like a comet, hence the term “coma.” Coma strongly influences image quality in the periphery of the field. And unlike filed curvature, it can’t be focused out. Coma often occurs with astigmatism in binocular optics.

Coma: Each cone of light focuses on different planes along the optical axis. (Image Credit: Wikipedia)

Astigmatism This optical aberration is caused by parts of the optical system like lenses or prisms not being completely rotationally symmetric which results in its inability to get a cross to optimal focus – either the horizontal line is sharp and the vertical line fuzzy, or vice versa. If you look at landscape or birds, it will mean that you cannot get a clearly defined focus point. This results in two different images superimposed on

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the retina. Of all the aberrations experienced by binocular enthusiasts, it is arguably astigmatism that is the most common. Indeed, according to recent studies, it’s estimated that two thirds of all US patients undergoing eye tests had astigmatism to varying degrees. Astigmatism in binocular optics is most often caused by misalignment of the lens elements. Astigmatism will result when lens elements within the optical path are not centered on each other (i.e. their principle axes do not align) or when lenses are tilted relative to the principle optical axis. Since astigmatism increases rapidly off axis it greatly influences image quality at the peripheral area of binoculars with a wide field of view. Thus, the effects of astigmatism become more prevalent in wide angle binoculars possessing large exit pupils and becomes far less pronounced when smaller exit pupils are employed. For example, I would expect astigmatism to be far more pronounced in the outer field of a 7×50 than a 10×30 instrument, with exit pupils of 7 mm and 3 mm, respectively. Astigmatism is best observed when a binocular is trained on a bright star at night. If the star is moved off axis, the effects of astigmatism become more pronounced near the field stops where the star appears to elongate. Just like coma, astigmatism cannot be focused out.

Illumination Drop-Off at the Edge of the Field Many binoculars I’ve tested don’t have even illumination from the center to the edge of the field. But that’s hard to test during daylight conditions when the sheer complexity of a typical binocular field overwhelms the visual senses. That’s why I always recommend testing for this at night when a bright Moon is in the sky. First center the Moon in the field of view and make a mental note of how bright it appears. Now move the Moon slowly away from the center of the field towards the field stops and observe how the brightness of the Moon changes. Chances are good that when the Moon is placed near the edges of the field it will appear significantly dimmer. Unfortunately, there isn’t very much one can do to ameliorate this effect. But it’s important to acknowledge, nonetheless. It will mean, for example, that fainter stars will fade and even disappear from view if imaged near the field stops, so it’s always best to view faint star clusters in the center of the binocular field to get the most out of your stargazing binocular.

Testing for Glare Glare is a very common phenomenon in binoculars and like many other things, some people are more sensitive to it than others. It’s caused by stray or peripheral light entering the optical train in such a way that it reduces contrast in an image. It can also be seen when the binocular is aimed near a bright light source, such as near

Field of View Estimation

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a setting Sun or artificial light source after dark. Another type is veiling glare, which occurs when light from above a target bleeds into the image causing an arc of diffused light usually seen at the bottom of the image. You can test for veiling glare simply by viewing the topmost boughs of a tall tree against a grey, overcast sky. It is most pronounced when you’re glassing in the same general direction of the Sun. Glare is generally most pronounced in the open field with a bright sky above your head. Maybe you’ve noticed that your binoculars deliver especially punchy images under the canopy of trees in a forest or while glassing from a hide or observer’s cabin. In these situations, the light from the sky is blocked by the trees or the roofs of those structures and so many folk could miss this altogether if they don’t observe out in the open. Pocket binoculars are especially prone to glare since they usually have very shallowly recessed objective lens. In addition, wide angle designs seem to have more of this also in my experience, How is glare minimized? By using the best antireflection coatings applied throughout the optical train, as well as having the objective lenses properly baffled immediately beyond the glass surfaces. Having decently recessed objectives is also helpful in this regard. Fortunately, veiling glare can be significantly reduced by shading the objectives with an outstretched hand in worst-case scenarios. It may also be reduced somewhat by experimenting with the positioning of the eyecups on your binocular. In some models I’ve noted that by moving the twist-up eye cups down one notch can significantly improve glare suppression.

Field of View Estimation Field of view estimates can be done in a variety of ways under the stars. If you know the angular separation of two stars, you can use it to estimate the size of your binocular field. I often use the stars of the familiar asterism of the Big Dipper which being circumpolar, is always above the horizon at my latitude. Here are a few measures: Alkaid to Mizar = 6.66 degrees Mizar to Alioth = 4.37 degrees Megrez to Dubhe = 10.37 degrees Dubhe to Merak = 5.35 degrees Merak to Phecda = 7.9 degrees Here’s a few other well-known star distances from around the sky, including the southern hemisphere: Beta Aurigae to Alpha Aurigae = 7.58 degrees Alpha Lyrae to Mu Lyrae = 2.57 degrees Delta Centauri to Pi Centauri = 8.10 degrees Beta Crucis to Delta Crucis = 4. 27 degrees

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For more accurate results, you can perform a star timing measurement. To do this, mount your binocular on a tripod and select a fairly bright star within 20 degrees of the celestial equator. Place the star in the exact center of the binocular field of view and time how long it takes in seconds for the star to reach the field stop. Then double this number to get how long it will take to cross the entire field. The size of the binocular field in angular degrees is given by the following formula:



 Number of seconds to cross the field  Cosine   of the star’s declination  360

  / 86164 

For example, suppose the star is Regulus with a declination of+12 degrees. That’s how far it’s located from the celestial equator. Suppose it takes 1500 s to cross the binocular field. Then the angular size of the field in degrees will be:

1500  cos12

o



 360 / 86164  6.13 degrees.



You should do this a few times to obtain an averaged value.

Resolution Tests Some binocular enthusiasts like to test how sharp their optics are by placing a special resolution chart at a distance and seeing how their binocular behaves resolving markings of various sizes. One of the most popular charts is the USAF 1951 resolution chart illustrated below. Do these charts tell you much about your binocular? In my experience, the answer is no. For one thing, visual acuity is a function of so many factors including: The precise magnifying power of the binocular The lighting conditions under which the observations are made The physiological state of the observer: e.g. fully alert vs. fatigued

Resolution Tests

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The USAF 1951 resolution test chart. (Image Credit: Wiki Commons)

Some other binocular enthusiasts place a monocular behind the eye piece of their binoculars to magnify the images still more. For example, an 8× monocular placed behind the eyepiece of an 8× binocular will yield a magnification of 8×8 = 64×. This kind of activity will show up aberrations in the binocular image that are quite invisible at 8× and to some extent is useful for assessing quality control between sample binoculars and also for determining quality differences between the barrels of the same binocular. But yet again, how useful are these kinds of tests? For one thing, there’s an enormous difference between 8× and 64× and truth be told you’re very unlikely to see these hyper-magnified aberrations in the 8× image because they’re way beyond the detection limit of the eye. To my mind doing these kinds of tests is more akin to torture than fun! You may also be surprised to learn that most binoculars are not even diffraction limited when viewed at the resolving magnification for a given aperture since most binocular optics have very low focal ratios (typically f/3.5 to f/5), compared with telescopes which have focal ratios of the order of f/6 to f/10. And what is the point of showing up your binocular’s weakness at 64× when it delivers perfectly fine images at 8× as it was intended to do so? For more on all things aberrational, be sure to check out Holger Merlitz’s excellent book, The Binocular Handbook, where he goes into great depths discussing the technical side of binocular optical aberrations amongst other things.

Chapter 28

Top Bargains in Today’s Market

While it’s generally true that you get what you pay for, it’s also true that there are some exceptional binocular bargains to be had. In this chapter I’ll be giving my top ten recommendations for those who wish to get the very best bang for buck. I’ll be covering binoculars from all categories from small pocket-sized instruments to large hand-held instruments. I’d be happy to use any of these instruments.

Zeiss Terra ED Pocket 8×25

An excellent pocket binocular: The Zeiss Terra ED 8×25 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_28

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The Zeiss Terra ED pocket glass offers excellent optics in an ultra-light-weight package. Serving up a wide 6.8-degree field, the images are razor sharp in the center and also at the edges. Though the original models were made in Japan, all the newer models are manufactured in China under Zeiss supervision. If you’re wondering if there are any quality differences between the Japanese and Chinese made models, the answer is no. Having tested both the Japanese and Chinese made units, they have identical ergonomics and optics, so nothing to worry about here. While there are more expensive pocket binoculars offered from Swarovski, Leica and Zeiss, the Terra ED pocket offers the best bang for buck in my opinion. The majority of binocular enthusiasts will not consider such a small instrument as their only instrument or even their most used binocular. Pocket binoculars are great if you must keep weight and size to an absolute minimum. They’re fantastic for casual birding, visiting museums and theatres and as a companion on walks or hikes. Having had plenty of experience with smaller 8×20 pocket glasses, I can safely say the 8×25 format is significantly easier to use. It has a larger frame than any 8×20 and a larger exit pupil so squaring on of one’s eyes is significantly easier to achieve. The Zeiss ED pocket is a tough little binocular and is fully water and fog proof and even has great hydrophobic coatings on the outer lenses reducing their need for cleaning. For $250 I think they represent excellent value for money.

Svbony SV 202 8×42 ED

An astonishing bargain in today’s market: the Svbony SV 202 8×42 ED

Oberwerk SE 8×32 ED

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The Svbony SV 202 series represent exceptional value for money in today’s market. Featuring ED glass, dielectric coatings and excellent broadband multi-coatings, the 8×42 ED is my favorite from the series. It has a nice wide field of view (7.5 degrees), and big sweet spot. The images it generates are excellent, high in contrast, great color correction and excellent sharpness across most of the field. It’s waterproof and fog proof. But it’s also a joy to hold in one’s hands and at 720 g, is quite light weight. Everything about the instrument seems well thought out; it has a very nice focus wheel, excellent quality twist up eyecups with plenty of eye relief, and the basic diopter compensation system located under the right ocular lens stays rigidly in place. I love its sleek but tough black rubber armoring too. The Svbony SV 202 8×42 ED is a sensational performer. For a bargain basement price of $179.00, it breaks all previous contenders for best price to performance ratio.

Oberwerk SE 8×32 ED

An Excellent compact binocular: the Oberwerk SE 8×32 ED

This new kid on the block totally stunned me when a unit arrived from Dayton, Ohio, the headquarters of Oberwerk. The brainchild of company founder, Keven Busarow, the Oberwerk SE 8×32 ED is a modern re-interpretation of the Nikon SE 8×32, a legendary Japanese binocular that was discontinued in 2014. Unlike the

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Nikon though, the Oberwerk SE incorporates ED glass in the objectives, has modern twist up eyecups with excellent eye relief, and is also nitrogen purged and sealed so its totally waterproof – an unusually weather resistant Porro prism binocular. It also has a similar field of view to the venerable Nikon SE 8×32 though. The views through the Oberwerk SE are quite simply stunning! The image is tack sharp from edge to edge and color correction is exemplary. Indeed, it’s one of the sharpest, contrast-rich compact binoculars I’ve had the pleasure of experiencing. This binocular has a heavy duty cast aluminum chassis overlaid by a thick layer of green rubber armoring. But while it does have some heft to it (798 g without the strap), it handles supremely well, with much of its weight tipped towards the rear which helps maintain a more relaxed, stable viewing experience. What’s most amazing about the Oberwerk SE 8×32 ED is its modest price: just $250 secures you one of these instruments.

Kowa SV II 8×32

Designed to be used: the Kowa SV II 8×32

For those who prefer compact roof prism binoculars, this quirky instrument from Kowa offers great optical and ergonomic features at a modest price. Most newbies are attracted to binoculars having ED glass, but, as I’ve demonstrated time and time again throughout this book, you don’t need fancy glass to get great optical performance. Recently re-vamped with a new green thick rubber armoring, these Philippines-made SV IIs have an unusually long focal length which minimizes all

Pentax Papilio II 6.5×21

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aberrations. The field of view is generous – 7.8 degrees – and it’s unusually well corrected at the field edges. My test unit had an impressive close focus of 1.68 m and some of the best-looking exit pupils on any binocular in any price range. These binoculars are fitted with high-quality lenses and coatings to deliver exceptional clarity and contrast. They feature a roof prism system that enhances resolution and image brightness. The binoculars are built to withstand tough outdoor conditions. They are made with a lightweight, durable polycarbonate body and are filled with nitrogen to prevent fogging. They are also waterproof and so can be used in wet weather conditions. The binoculars are designed with a comfortable grip and a large, smooth focus wheel that can be easily adjusted even when wearing gloves. It also features excellent twist-up eyecups that can be easily adjusted to accommodate eyeglass wearers. The Kowa SV II 8×32 binoculars come with a variety of additional features, including a carrying case, neck strap, and a limited lifetime warranty. They are also tripod adaptable, which allows for steady viewing during extended periods of use.

Pentax Papilio II 6.5×21 This excellent little reverse Porro binocular from Pentax has taken the naturalist world by storm. With really nice optics and a wide 7.5-degree true field, the Pentax Papilio II 6.5×21 has specially designed objectives that taper in when you want very close focus, just as human eyes begin to cross as an object is brought steadily closer to the face.

An Extraordinary Performer: The Pentax Papilio II 6.5×21

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As a result, these have the closest focus of any known binocular – just 50 cm in fact – making it ideal for studying objects up-close and personal such as insects, rocks and flowers. Focus back out and you have a normal functioning binocular magnifying at distance. Weighing just 290 g, it’s lighter than some pocket binoculars I’ve tested, so is ideal for all sorts of activities, including hiking in the mountains, birdwatching in good light, as well as watching sports events and travel. Its only downside is that it’s not waterproof, so extra care must be taken to keep the optics in tip top condition.

Opticron Imagic TGA WP 10×50

A Nicely Designed Classic Porro: The Opticron Imagic TGA WP 10×50

This sturdily built Porro prism binocular from Opticron has very nice optics, a 30-year warranty, treated with the company’s proprietary F multicoating ensuring bright, high-contrast images. Like the Oberwerk SE, it’s waterproof and nitrogen purged so will present no problems in even the wettest of conditions. Unlike older Porro designs, the Opticron Imagic TGA WP 10×50 features modern twist up eye cups and excellent eye relief for eye glass wearers. I love the design of the right eye diopter adjustment on this instrument. It has nicely machined mini grooves that click into place so maintaining its position indefinitely. Although its field of view is only 5.3 degrees, it’s very well corrected, even at the edges, and its relatively low weight of about 820 g means it won’t put too much strain on your neck if you carry

Barr & Stroud Series 8 8×42

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it round for prolonged periods of time. What the Opticron really excels at is astronomy: it’s brilliant for sweeping up open clusters, nebulae and the brighter galaxies that grace our skies. It’s also excellent for following the phases of the Moon. For the steadiest views, I’d recommend a monopod with this instrument.

Barr & Stroud Series 8 8×42

A Very Affordable High-Performance Roof Prism Binocular: The Barr & Stroud Series 8 8×42

If you’re after a really good binocular with an open bridge design, then you ought to check out Barr & Stroud’s economically priced Series 8 8×42 roof prism binocular. Optically and ergonomically, these instruments are a real treat with excellent build quality for their modest price tag. Featuring a very well corrected 8.1-degree field, the images are bright, sharp and contrast rich. Glare is very well suppressed. Handling is exceptional. The open bridge design is easy to get your fingers wrapped around the barrels for an extremely relaxed view. It’s also ideal if you need to use the instrument single handedly. The fully multicoated and phase corrected roof prisms deliver very delightful images in all weathers and the twist up eyecups offer ample eye relief to use with glasses. Barr & Stroud is not a name very familiar to US-based binocular enthusiasts but are growing in popularity here in the UK and in Europe. Sold by their parent company, Optical Vision Limited (OVL), they can be

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ordered from the UK to just about any location in the world. One slight niggle is the overly stiff focus wheel but over time and a bit of use, this should loosen up a bit.

Canon IS 8×20

High-Tech Stabilization: The Canon IS 8×20

If you’re after a taste of image stabilized binocular viewing, check out this dinky little instrument from Canon. Though it has the specifications of a pocket binocular, it’s considerably larger and thus is easier to use. Press the stabilizing button and you get rock-steady images allowing you to see many more details than you would otherwise see. Optically, it’s quite excellent; far better in fact than I had anticipated and has a wide field of view (6.8 degrees). Powered by a small lithium-ion battery, it can be operated for many hours in the field. The Canon IS 8×20 is the least expensive of this company’s extensive range of image stabilized binoculars but it will certainly whet your appetite for some of the larger models. The Canon IS 8×20 retails for about $499 in today’s market.

Helios StarField 2×40

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Helios StarField 2×40

Explore the Heavens with the Helios Starfield 2×40 binocular

Now for something completely different. This nifty little Galilean binocular is fantastic for viewing constellations from a dark sky site. Featuring fully multicoated optics, during daylight hours it serves to greatly enhance human vision, by boosting the eye’s natural magnification and increasing resolution and contrast. It can be used in many situations including watching sports events, inspecting buildings, watching meteor showers, and even some short-range birdwatching. I can’t think of a better instrument to learn the constellations as they move across the sky with the march of the seasons. It comes with a lanyard if you wish to wear it round your neck and a nifty clamshell case that can fit in any pocket or glove compartment. The Star field retails for about $120.

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Celestron SkyMaster 15×70

Explore the Deep Sky with a Celestron SkyMaster 15×70

If you’re looking for a decent entry-level high-power binocular for long range terrestrial viewing or deep sky astronomy, then look no further than this best-selling binocular from Celestron. The optics are multicoated and employs BaK4 prisms for nice high-contrast views. A basic instrument like this will show up a bit of color fringing on high contrast targets but it is acceptably low and largely unobtrusive. The 4.4 degree field is large enough to frame a whole host of the glories of the night sky, including the Pleiades, the Hyades, the Sword Handle of Orion, the Perseus Double Cluster, brighter galaxies in Ursa Major and Leo and even hunting for comets. It’s also great for looking at the Moon at higher power than normal binoculars. Weighing in at just over 1200 g, you’ll need a monopod or lightweight tripod to get the steadiest views but it can also be enjoyed for quick handheld use. At $75, it’s arguably the best selling astronomy binocular in the world!

Chapter 29

A Brief Survey of Classic Binocular Literature

As an enthusiastic, life-long collector and reader of astronomical and natural history literature, I’ve always appreciated the power and value of the printed word. Having re-ignited a keen interest in binocular observing, I was somewhat saddened to see that many great works of binocular optics and astronomy were being largely ignored by amateurs. To help redress this balance, this chapter will take a close look at a number of books dedicated to the art of visual observing using ordinary binoculars, where I offer short reviews of a number of inexpensive works. Their value lies in the collective knowledge of the authors who have produced these works; experience that far exceeds those offered by the self-proclaimed ‘experts’ constantly chattering on internet forums. And you will save yourself a small fortune – time and money – by heeding their advice.

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_29

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Exhibit A: The Binocular Handbook

Author: Holger Merlitz Publisher: Springer Nature ISBN: 978-3031444074 1st Edition: 2023, pp. 300 Price: £39.99

This new English edition based on Dr. Merlitz’s original German book, explores the technical side of binocular optics in exquisite detail. Recognized worldwide as an authority in binocular history and optics, Merlitz walks the reader through the physics of optical aberrations as applied to binoculars, explaining how and why certain design features are selected by optical engineers. It’s also a mine of information on the human eye and why binoculars behave as they do and how human vision impacts on the perception of optical quality. In just nine chapters, it’s packed full of the relevant physical principles and important historical tidbits, I consider it complementary to the approach adopted in this book, helping readers make informed decisions about the binoculars they should avoid or buy. This is like having an expert right by your side as you explore the fascinating world of binocular optics. It’s also extremely well referenced for those who wish to conduct further research in a variety of esoteric topics. A fascinating read!

Exhibit B: Choosing Binoculars for Bird Watching and Wildlife

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 xhibit B: Choosing Binoculars for Bird Watching E and Wildlife

Author: Calvin Jones Publisher: Ireland’s Wildlife ASIN: B00GMSZPE0 1st Edition: 2017, pp. 51 Price: Paperback $7.44

This neat little booklet written by Welsh naturalist, Calvin Jones, goes through the basics of binoculars, offering some solid advice on what features to look for in a good birding binocular. Jones does a good job explaining the jargon associated with binoculars helping you make a more informed decision about which models to avoid and which to pursue. Jones, who founded Ireland’s Wildlife back in 2011 to encourage the general population to explore and engage with Ireland’s wild places has lots of experience using binoculars in all price categories and can recommend bargain models that won’t break the bank. A short, quick read.

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Exhibit C: How to Become an Urban Birder

Author: David Lindo Publisher: Princeton University Press ISBN: 978-0-691-17962-9 Price: £13.75 First Edition: 2018, pp. 232

David Lindo is one of the UK’s most accomplished birders. An inveterate traveler and writer, Lindo is famous for bringing the wonderful world of bird watchers to an urban audience. With a foreword by celebrity chef, Jamie Oliver, Lindo launches the book with an excellent overview of the urban landscape and the surprisingly rich habitats they sustain. Lindo then covers the techniques of urban birding before going over all the tools of the trade, including binoculars. Though it’s obvious he’s a Leica fan, Lindo does his best to remain objectively neutral offering his advice on binoculars. The book is lavishly illustrated throughout. This is a great resource for the many millions of people who live most of their lives in a town or urban environment, from car parks to canal walks, birding from roof tops and skyscrapers. Overall, the Urban Birder is an inspiring and very enjoyable read.

Exhibit D: Discover the Night Sky through Binoculars: A Systematic Guide…

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 xhibit D: Discover the Night Sky through Binoculars: E A Systematic Guide to Binocular Astronomy

Author: Stephen Tonkin Publisher: BinocularSky Publishing ISBN: 978-1-9164850-0-6 Price: £10 1st Edition: October 2018, pp. 145

Want a good binocular astronomy guide for Christmas? I have the perfect recommendation for you! Stephen Tonkin’s new book is sure to appeal to binocular enthusiasts of all ages. Tonkin is no flash in the pan. He has authored or contributed to many books I’ve acquired over the years and writes a monthly column on binocular astronomy for Britain’s BBC Sky at Night magazine. He also maintains an excellent website dedicated to binocular astronomy, which can be accessed here. So I was in no doubt about my expectations concerning his new offering and boy does it deliver! Though it looks like a self-published book, Discover the Night Sky through Binoculars, is a witty and authoritative survey of what can be realistically achieved with binoculars. After a short introduction, the first three chapters cover all the technical stuff you’re likely to need to know about how to get the best out of a decent binocular. There is a particularly humorous mention of some rubbish

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models, which Tokin refers to as “binocular-shaped objects.” He avoids making specific recommendations about specific models though, which is a good thing, as many units can now be purchased fairly inexpensively that can provide a lifetime of great astronomical views. The remainder of the book is divided up into the many binocular sights arranged in a month-by-month sequence. His superlative first-hand knowledge of the heavens shines through as he clearly and effectively shows the reader how to locate each target. All the showpiece binocular targets are covered in this book, and many more besides. Though the sky maps printed in the book are a bit small to see well, one can always download higher quality maps from his website which you can study at your own leisure. I love his description of a phenomenon called pareidolia, which describes the psychological condition of seeing patterns in the starry heavens that are not really there! It’s very easy to use this book, especially if you already have some experience of the night sky, but it will work equally well for newbies. Indeed, it’s almost like having an expert right beside you as you make your own binocular observations. The end of the book features several useful appendices, which cover important topics, such as how to determine the size of your dilated pupil, how to test your binocular for defects, as well as sound advice on how to maintain your binocular in tip-top condition over the months and years. This is a great, no-frills book, with simple black & white illustrations, but it’s packed full of excellent observing projects that will keep you blissfully happy for many years to come.

Exhibit E: Binocular Highlights: 109 Celestial Sights for Binocular Users

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 xhibit E: Binocular Highlights: 109 Celestial Sights E for Binocular Users

Author: Gary Seronik Publisher: Sky & Telescope ISBN: 978-1-940038-44-5 Price: £18.99 2nd Edition 2017, pp. 112

Gary Seronik is no stranger to those who have enjoyed Sky & Telescope magazine over the years. He wrote a regular column; Binocular Highlights; for Sky & Telescope between 1999 and 2016, where he thereafter became the editor of the well-regarded Canadian astronomy periodical, SkyNews. This neat little book features 109 objects from all over the northern sky that can be enjoyed with binoculars. After a good introduction, Seronik summarizes all the things you need to know about binoculars and makes a specific recommendation that a 10×50 unit is probably the best compromise between power and portability. That said, he admits that he is an avowed fan of image stabilized models, such as his favorite; a Canon 10×42IS. The remainder of the book is divided up into chapters covering the four seasons of the year, where he presents a series of brief but very engaging mini-essays on the most celebrated of all binocular targets, concentrating on those objects that are best seen from mid-northern latitudes, though he does have an occasional entry of sights only visible in the deep south, such as the illustrious Omega Centauri. The book is lavishly illustrated throughout, with full color charts typifying a 10×50 binocular view, on pages made from thin cardboard rather than regular paper, and is ring bound for convenient use in the field.

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If I have any quibbles to make about this book, they are minor; I just wish he could have included more objects. That said, I suspect that, for the vast majority of observers, yours truly included, binocular observing is not really about pushing the envelope to observe overly difficult or challenging objects. The targets themselves are so beautiful that you’re likely to observe them many times during a season, where their orientation in the binocular field changes as they wheel across the sky. Thus, Binocular Highlights is designed for observers who just enjoy looking at the same objects as the season’s progress; and that’s fine. Now in its second edition, Seronik has added 10 new entries over the original book, which is a bonus. In short, you can’t go wrong with this excellent little field guide but all the while, I can’t help but think those lovely colored charts go a bit to waste when manhandled in the field.

Exhibit F: Stargazing with Binoculars

Authors: Robin Scagell & David Frydman Publisher: Philips ISBN: 978-0-540-09022-8 Price: £13.74 (second edition) 1st edition, 2007, pp. 208

It is oft stated that the best way to start out in the fascinating hobby of astronomy is to purchase a good binocular. There is a great deal of truth to this sentiment. Many folk who express a casual interest in stargazing quite often become disillusioned by

Exhibit F: Stargazing with Binoculars

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it, perhaps because they live in a heavily light polluted location, or they made the mistake of purchasing a large, complicated telescope that is just a pain to set up in the field. The wonderful thing about binoculars is that they are much more versatile than dedicated astronomical telescopes, since they can be used during the day to have a good look around, for nature treks, birding, camping, watching sports and the like. Stargazing with Binoculars takes a much more pedestrian path through the fascinating world of binocular observing. Written by two veteran stargazers, Robin Scagell and David Frydman, who have amassed an enormous amount of field experience with more binoculars than you could shake a proverbial stick at. Their book, now in its second edition, shows you how the sky works and then presents a month-­ by-­month overview of what can reasonably be seen using binoculars of various sizes. Unlike the aforementioned books, the authors include sections on lunar, planetary and solar observing, before engaging in a comprehensive survey of the binocular market. This is a great book to learn about how binoculars are made, what the various models offer the observer and how to test binoculars prior to purchasing. It also features an excellent chapter on how best to use a given binocular; whether it be hand-held, harness stabilized, or securely mounted in a variety of configurations, from simple monopods to complex binocular mounts. Stargazing with Binoculars provides a wealth of information that any interested reader will find useful, including how to estimate binocular fields using star tests, making sketches of what one sees in a binocular, as well as sections on observing comets, meteors, artificial satellites and much more besides. It also provides a comprehensive overview of the southern sky, so it is equally useful to those observers who enjoy life in the antipodean. This is a fabulous, cost-effective book for all binocular enthusiasts, featuring a generous number of full colour images to complement the text, and although I have not seen the second edition (2013), I’m sure it will be just as good if not better. All in all, a great stocking filler for the binocular enthusiast!

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 xhibit G: Observing the Night Sky with Binoculars: E A Simple Guide to the Heavens

Author: Stephen James O’Meara Publisher: Cambridge University Press ISBN: 978-1843155553 Price: £24.99 2008, pp. 148

I’ve always been a fan of Stephen James O′ Meara, a highly accomplished visual observer, who served on the editorial staff of Sky & Telescope for many years before joining Astronomy (USA) as a regular columnist. I have collected and enjoyed all of his books over the years and would heartily recommend them to anyone. Though he is perhaps better known for his studies of deep sky objects, observing from the big Island of Hawaii using 4- and 5-inch refractors, I was glad to see that he produced a book dedicated to binocular observing to complement his telescopic adventures. Observing the Night Sky with Binoculars is a large book compared with all the others mentioned above, with dimensions of 12×8″. The book opens with a great introduction to exploring the night sky, featuring the Big Dipper as a starting point to find your way around the sky. Here, you’ll learn how to estimate angular separations between objects, how best to perceive star colors, as well as a good introduction to the physiology of the human eye. A surprising amount of information can be gleaned by studying the Big Dipper and how it points to many other interesting objects nearby in the sky. What is somewhat surprising about this work is that O′ Meara categorically states that he used inexpensive binoculars  – 7×50s and

Exhibit H: Handbook of Binocular Astronomy: A Complete Guide to Choosing and…

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10×50s – in preparing the material for this book. He does not dwell on the intricacies of binocular construction or advocate any particular brand of binocular, in contrast to his other books, where he strongly advertises the virtues of small, expensive TeleVue refractors (been there, done that, not going back). The book continues by taking a seasonal look at the treasures of the binocular sky, covering each season from spring, summer, autumn and winter. What is immediately obvious is that O′ Meara has an encyclopedic knowledge of the mythology of the heavens, with a particular interest in ancient Egyptian sky lore. While this is all very good, I personally would have liked less discussion on mythology and more about actual observing, but everyone has their own take on how best to present the wonders of the night sky and, in this capacity, O′ Meara carries his own torch. All the illustrations in this book are black & white, but the charts and diagrams are very easy to read and assimilate. In addition, there is a wealth of good drawings made by the author in this book which greatly adds to the value of this work and while many targets can be seen by the averagely keen eye, some are very challenging, requiring both very dark and transparent skies and a very keen eye to fully appreciate. Though it is a bit more pricey than the other books discussed above, anyone with a keen interest in the binocular sky will appreciate this very well written book, and I for one feel fortunate indeed to have a copy in my personal library.

 xhibit H: Handbook of Binocular Astronomy: A Complete E Guide to Choosing and Using Binoculars for Astronomers – Whether Beginners or Not-So-Beginner

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Author: Michael Poxon Publisher: Starman Books ISBN: 97809562394-0-2 Price: £12.96 2009, pp. 397

Now for something completely different! Michael Poxon is a name unknown to me, but that ought not deter a curious individual from investigating a book. Often times, to my growing knowledge, it’s ordinary folk who come across as being the most sensible and the most experienced, as opposed to the loud-mouthed guffaws you see on internet forums. And Poxon puts his all into this very large book! It begins, as all the others do, by stressing how important binoculars can be to the novice and dedicated astronomer alike. He offers sage advice in purchasing good binoculars, you know; what to avoid and what not to avoid. Curiously, he advises against image stabilized binoculars for the following reasons; they’re often very heavy (over a kilogram) and so do nothing to stave off arm ache, they rely on battery power (which he finds to be a nuisance) because they lose their charge in a few hours. They are also very expensive and the author feels that the money is better spent on conventional optics. Furthermore, he rightly points out that better stabilization can be achieved by using a homemade monopod. In this, I wholeheartedly agree; my brief experiences with image stabilized units a few years back left me feeling a little underwhelmed and I felt the images were, let’s say a tad “artificial.” And although Poxon certainly advocates the cheap and cheerful Porro prism varieties, he also sings the praises of compact, roof-prism models because of their labor-­ saving low mass in comparison to the former, albeit at some additional cost to the consumer. It is also clear that Poxon is a highly seasoned enthusiast, who has travelled to many places around the world to observe the binocular heavens. Ever the practical man, he has the presence of mind to include the construction of effective, low-tech dew shields for his 10×50s used during his prolonged binocular surveys, which he often mounts astride his 36 cm telescope. Chapter 2 deals with the basics of the celestial sphere, the magnitude scale of stars, as well as a very useful table indicating the magnitude limits, field of view and angular resolution of various popular models used by the amateur community. He also offers up valuable advice on how much one can gain in stabilizing a binocular; on page 31, for example, we learn that one can go a hefty 1.5 magnitudes deeper on a stabilized system compared with hand holding; and I’d call that significant! What follows are excellent general overviews of the Sun, Moon and planets, eclipses etc. Poxon does an especially good job in helping the reader recognize the many lunar craters and mountain ranges within the resolution remit of a typical 10×50 binocular with simple but very effective lunar maps. In Chap. 5 (which is mistakenly printed as Chapter 3), he delves into the fascinating world of deep sky astronomy and what follows is a very impressive listing of interesting variable stars, double and multiple stars (both wide and close-in) as well as a treasure chest of deep sky objects from the entire pantheon of constellations in the sky (the whole 88 are represented).The data is arranged in the form of notes which can be easily followed by the interested observer.

Exhibit I: Deep Sky Observer’s Guide

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While the illustrations are not of the highest quality, they are generously presented and can be followed without much fuss. The end of the book contains a series of useful appendices with particular emphasis on variable star monitoring. This is an excellent book and, true to its opening lines, has something for every level of enthusiast; from newbie to veteran. I was pleasantly surprised by its excellent content, written by a well-heeled amateur.

Exhibit I: Deep Sky Observer’s Guide

Author: Neil Bone Publisher: Philips ISBN: 0-540-08585-5 Price: £9.99 2004, pp. 223

An honorary mention. The late Neil Bone (1959–2009) was a highly accomplished deep sky observer, public speaker and writer. A microbiologist by profession, he spent many of his evenings observing the glories of the deep sky from his Sussex home. Despite his notoriety and universal respect by the British astronomical community, Bone used simple equipment throughout his life, which included a ShortTube 80, a 10×50 binocular and a small Dobsonian telescope to accomplish all his observing goals. Deep Sky Observer’s Guide is a wonderful little book for beginning stargazers, featuring a rich selection of deep sky objects that are accessible to anyone with the same equipment. The first two chapters cover the basics of deep sky

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observing, including a great overview of the celestial sphere as well as the equipment and observational skills amateurs use to good effect to divine its many secrets. The rest of the book has chapters dedicated to particular deep sky real estate, including galaxies, asterisms, globular clusters, diffuse nebulae, open clusters, planetary nebulae and supernova remnants. Although the book is not about using binoculars per se, Bone used his 10×50 to make excellent observations of many of his subjects and are preserved for posterity in the pages of this literary gem. To see just what can be accomplished with a humble 10×50 binocular, this now classic text is a great place to spend some time. Many of the deep sky objects he describes were observed using his trusty binocular, and despite his premature passing, his rich word pictures still have the ability to inspire me. In amatam memoriam.

Exhibit J: Binocular Stargazing

Author: Mike D. Reynolds Publisher: Stackpole Books ISBN: 978-0-8117-3136-2 Price: £5.99 2005, pp. 213

The late Mike D.  Reynolds is a name familiar to many American and Canadian observers. A professor of astronomy and Director Emeritus at Chabot Space & Science Center at Oakland, California, he is probably best known for his popular writings in Astronomy Magazine, as well as his excellent books on eclipses and

Exhibit J: Binocular Stargazing

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meteor watching. Binocular Stargazing is a very well written and thought-out book, covering a lot of ground. After a short foreword from celebrated comet discoverer, David H. Levy, the first three chapters provide all the information you’re likely to want to know about binoculars, past and present, written in a friendly yet authoritative style. What is very refreshing to see in this title is that, like nearly all the other authors of binocular astronomy, Reynolds emphasizes that one can obtain excellent results with only a modest investment; a philosophy yours truly also shares. Chapters 4, 5, 6, and 7 offer excellent overviews of how binoculars can be used for lunar & solar observing, before engaging in a thorough but non-technical treatise on the wider solar system objects, the distant stars, as well as presenting a great introduction to deep sky observing. One slight niggle pertains to the author’s persistent use of the term “pair of binoculars” throughout the book. Though certainly not a big deal and still used my many observers, the phrase doesn’t really make a whole lot of sense. The word ‘binocular’ implies duplicity. Better to use ‘binocular’ to refer to a single instrument and ‘binoculars’ when referring to more than one such instrument. Chapters 8, 9, 10, 11, and 12 offer up one of the best surveys of the binocular sky I’ve seen, arranged in seasons, ending with a special chapter devoted to observing from southern skies. Throughout, Reynolds displays his first-hand experience in the field and has a talent for making the subject matter very accessible. The science presentation is first-rate, as one would expect from a guy with an advanced degree in the science. Variable stars are particularly well represented in this title. What I particularly liked is the inclusion of extensive appendices (A through I) at the back of the book. One appendix in particular, emphasizes the age-old tradition of note-making and keeping, sketching and the like; an activity of great importance even in this age of instant digital gratification. The text is quite generously illustrated in monochrome, though some of the images could have come out better, they are certainly good enough not to distract or confuse the interested reader. All in all, Binocular Stargazing is a highly recommended book for binocular enthusiasts, and I for one will continue to enjoy dipping in and out of it in the future.

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 xhibit K: Touring the Universe Through Binoculars: E A Complete Astronomer’s Guidebook

Author: Philip S. Harrington Publisher: Wiley ISBN: 978-1620456361 Price: £18.34 1990, pp. 306

It is hard to believe that nearly 30 years has gone by since the publication of Philip Harrington’s, Touring the Night Sky with Binoculars. Back then, I was still an undergraduate, with only a 7×50 porro prism binocular and a 60  mm classic refractor which I used to explore the night sky. Pluto was still a planet and the first CCD imaging pioneers were beginning to tinker with their crude chips to obtain electronic images of the celestial realm; most were still using photographic film. And while amateur astronomy has changed beyond measure in only three decades, Harrington’s book provides solid evidence that some texts will never go out of fashion. The preface of this now classic text reveals the modus operandi of the author, who admits that the book was primarily written for himself! Giving an honourable mention to Garrett P.  Serviss’ 1888 work, Astronomy with an Opera Glass, Harrington weaves together an enormous body of field knowledge, which both complements and far exceeds the collective wisdom of his distinguished Victorian predecessor.

Exhibit K: Touring the Universe Through Binoculars: A Complete Astronomer’s…

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Harrington was one of the earliest amateur astronomers to call attention to the considerable advantages of using two eyes, explaining that gains of up to 40% can be achieved in resolving fainter, low-contrast deep sky objects. This much is made clear in the short introduction to the book, but the march of time has thoroughly vindicated his binocular evangelism, as evidenced by the great popularity of bino-­ viewing, as well the growth of binocular astronomy in general among the global amateur community. The book, as Harrington makes clear, is actually a collection of concise notes which he himself compiled in his adventures under the night sky. Eschewing any discussion on equipment, the author launches into fabulous discussions of the Moon, Sun, planets and minor bodies of the solar system, before wading into the pantheon of objects existing far beyond our shores. Beginning in Chap. 7, Harrington provides concise but highly accurate depictions of a sumptuous listing of deep sky objects:- stars, open clusters, nebulae and galaxies, as seen in a variety of binoculars, both large and small. In a departure from most other authors, Harrington recommends the 7×50 above the 10×50 as the best all round instrument for hassle-free binocular observing, but it is also evident that he has gained a considerable amount of experience behind a larger 11×80 instrument. Every constellation in the heavens is discussed separately, rather than approaching the subject from a season-by-season perspective. This works supremely well, being more reminiscent of Robert Burnham Junior’s three volume work, Burnham’s Celestial Objects, than anything else. While this hardback text was not designed to be used in the field, it is an indispensable work for planning and reflecting upon the sights seen on a clear, dark night. I find myself using it to compare and contrast it to my own observations and notes and to challenge myself to see more with a given instrument. Remarkably, any discussions on binoculars per se are reserved for short appendices at the back of the book. Like all truly seasoned observers, Harrington avoids making specific recommendations, emphasizing that one can do a great deal with modest equipment. Appendix B in particular, discusses how resourceful amateurs have hobbled together exceptional mounting strategies that greatly increase the comfort of viewing through truly giant binoculars, featuring such individuals as Norm Butler, Jerry Burns and John Riggs, to name but a few. Although technology has certainly moved on (just look at the quaint photographs used to illustrate the text!) since Harrington first collated the work for this text, it is unlikely to be superseded by anything in the modern age. Indeed, it remains, for me, the definitive volume of binocular astronomy and shall continue to hold a special place in my astronomical library. Thoroughly recommended!

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Exhibit L: Exploring the Night Sky with Binoculars

Author: Patrick Moore Publisher: Cambridge University Press ISBN: 0 521 30756-2 1986, pp. 203

Some books just never go out of fashion. As a long-time fan of the late Sir Patrick Moore, I can vouch for having enjoyed many of his astronomy books over the years. This charming book on binocular astronomy is a real classic, as enjoyable to read today as it was when it first came off the printing press. Moore vehemently defends the use of binoculars  – particularly 7×50s  – by beginning sky gazers and offers much advice in support of considering binoculars over a telescope to newcomers to the night sky. After walking the reader through the various binocular formats used by amateur astronomers, he explores a wide variety of celestial objects accessible to binoculars, including double and variable stars, clusters nebulae and galaxies, the march of the seasons and the appearance of new constellations in the sky. Following these chapters, Moore concentrates on each constellation in turn, highlighting the showpieces from each of them and how best to observe them. Later in the book, Moore writes an excellent chapter on observing the changing phases of the Moon and what the binocular observer can glean from such observations. The book ends with a short but informative chapter on observing the planets as well as hunting down comets and shooting stars. This a great book that has a permanent place in my astronomical library.

Exhibit M: Binocular Astronomy

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Exhibit M: Binocular Astronomy

Author: Stephen Tonkin Publisher: Springer ISBN: 978-1-4614-7466-1 Second edition, 2014, pp. 435 Price: £34.99

In this the second book by the author Stephen Tonkin, the reader gains a much deeper understanding of the workings of binoculars for astronomical observing. Taking a semi-technical approach, Tonkin includes invaluable data on binocular optics, including interesting discussions on prisms, lenses and the most widely used eyepiece designs making up binoculars. He then describes the relative strengths and weaknesses of using binoculars of various sizes as well as excellent chapters on how best to observe the night sky through binoculars, by hand holding, using a monopod and other types of mounting conjured up by clever amateurs. Tonkin does a great job clarifying many technical terms encountered in the world of binoculars but in such a way that the reader is not left overwhelmed. There is also an excellent chapter discussing the maintenance of binoculars. The second part of the book is devoted to the full pantheon of astronomical targets accessible to the binocular astronomer throughout the astronomical year. Comprehensive charts and maps make finding these objects much less challenging than you might expect. Each binocular object explored is accompanied by the size of instrument best employed to see it together with some basic notes on each target. The book ends with a series of very useful appendices, including the angular distances between many of the brighter stars in the sky. I found this particularly helpful whilst determining the size of the field of view served up my different binoculars and checking manufacturer claims. Make sure you get the latest, second edition version of this book.

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Concluding Words Just like in the case of telescopes, we are fortunate to live at a time in history where quality binoculars can be had for relatively small amounts of money. There is a bewildering number of models available to suit everyone’s budget, and even the least expensive units are immeasurably superior to the naked eye. But as all the authors of these books make clear, what is most important is that one gets out under a starry sky and use the instrument. Of course, one can decide to avoid the collective wisdom of these writers, but it will most likely lead the researcher down many dead ends (I speak from the well of my own experience), where one is tempted to keep buying ever ‘better’ models in the mistaken belief that grass is really greener on the other side. Unfortunately, this is largely the state of affairs on our telescope and astronomy internet forums, where folk seem to be more interested in a said instrument than actually using it. This is highly regrettable; indeed it is a very real kind of poverty, missing, as it were, the woods for the trees, but it can easily be countered by just getting on with the equipment we have whether it be birding or stargazing. I hope you have found these mini-reviews of some use and I do hope that amateurs everywhere will avail of these well thought out resources, written by people who have a real passion for all things binoculars and observing the natural world and for sharing their knowledge with others.

Chapter 30

Classic Binoculars

A Fully restored Opticron Dioptron 8×32

With all the great gear that’s now available to the consumer, it’s easy to dismiss binoculars that were made in the past. But that’s an unfortunate position to adopt because my own experiences of some classic binoculars have been nothing short of thrilling. Moreover, some are so good and so well made that they present a viable way to acquire high quality optics at prices that won’t break the bank. In this chapter, I’ll be taking a look at some classic models I’ve explored, as well as my © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_30

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experiences with them. I’ve also invited a few other individuals to discuss some models I’ve not had the pleasure of trying out in person. In my exploration of the binocular market, I spent the majority of my time testing and evaluating roof prism binoculars, but as I gained some experience of Porro prism binoculars, I quickly came to appreciate their many virtues, so much so that I personally prefer them as a general rule to roof prism models. That led me to explore a variety of older models from respected binocular makers to learn more about their ergonomic and optical qualities.

The Zeiss Jenoptem 8×30

A late 1980s Carl Zeiss Jenoptem 8×30 with the T3M Multicoating

The Carl Zeiss Jenoptem 8×30 binoculars are a classic model of binoculars that were produced by the famed German company Carl Zeiss Jena from the 1950s until the early 1990s. These binoculars were highly popular and widely used by nature enthusiasts, bird watchers, and hunters during this time. The history of the Carl Zeiss Jenoptem 8×30 binoculars dates back to the nineteenth century when Carl Zeiss, a German optical instrument maker, founded his company in 1846. Zeiss was a pioneer in the field of optics and made significant contributions to the development of the microscope and the telescope. In the early twentieth century, Carl Zeiss

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Jena began producing binoculars, and their products quickly gained a reputation for being some of the best in the world. During World War II, the company was heavily involved in the production of military equipment, including binoculars and other optical instruments. After the war, Carl Zeiss Jena became a state-owned company in East Germany, and the production of binoculars continued. The Jenoptem 8×30 binoculars were first introduced in the 1950s and quickly became popular due to their high-quality optics and durability. The Jenoptem 8×30 binoculars were designed to be lightweight and compact, making them ideal for use in the field. They were also affordable, making them accessible to a wide range of people. Indeed, it is arguably true that the Zeiss Jenoptem 8×30 was one of the best-selling binoculars for civilian use ever produced. Despite being produced for nearly  40 years, the design of the Jenoptem 8×30 binoculars remained relatively unchanged, and they continued to be highly regarded by nature enthusiasts, bird watchers, and hunters alike. Today, the Carl Zeiss Jenoptem 8×30 binoculars are considered a classic model of binoculars and are highly sought after by collectors and enthusiasts alike. Although they are no longer in production, their legacy lives on, and they continue to be regarded as one of the better binoculars ever made. I purchased my classic Zeiss Jenoptem from ebay, but it wasn’t easy to make the right choice. There were many Zeiss DDR Jenoptem models available for sale in all sorts of condition. That helps stabilize their market price to between about £60 and £100 UK. I settled on a late-1980s model (serial # 6722320), with the famous T3M multi-coatings, which, for their day, were well ahead of anything else on the market. The unit I purchased was in excellent working condition, without any visible damage to the optics, and devoid of internal fungus infestations. The binocular came in its original brown leather case, which needed a few stitches to restore it to full working order, as well as a nice leather lanyard. The objectives looked pristine after I gave them a thorough clean. Some background research informed me that the leather case originally supplied with the instrument was lined in a fetching rose-­ colored lining.

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They certainly don’t make binocular cases like they used to: check out the high-quality leather case with beautiful rose colored lining

The ocular lenses of the Zeiss Jenoptem 8×30 with their pretty magenta colored lens bloom

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The instrument arrived well collimated. The central focus wheel operated smoothly, with no free play or backlash. I was very impressed when I took my first look through it. The image was bright and very sharp within its very generous sweet spot. I was especially taken aback by the enormous field of view; fully 8.4 angular degrees! The diopter compensation ring, located under the right ocular, moved smoothly but was easily nudged out of place. Observing in an open field, in bright, spring daylight, showed that glare was quite well controlled but certainly more than I’ve seen in most modern instruments. Still, the sheer majesty factor of the field of view made a very deep impression on me. I was especially taken by the wonderful 3D pop to the images, which I found very engaging. As this instrument was more than 30 years old, I was expecting some internal reflections when I turned the instrument on a bright light source; and rest assured, a few did show up. The instrument presented a very warm image but it was not as yellow as other reports have suggested. The reason why so many of these classic Porro prism binoculars from yesteryear possessed BaK4 prisms with a lower light transmission at shorter (blue) wavelengths, resulting in a higher proportion of green and red (hence yellow) being transmitted to the eye. Maybe this was because I had a quite late model of this world-famous binocular – I’m not entirely sure- but I was surprised to learn that its maximum light transmission peaked at about 91% in the optimal, green-yellow visual range, according to spectrophotometric measurements conducted by Allbinos on a slightly earlier, 1985 model. Like so many classic binoculars, it’s very short on eye relief, but amazing if you manage to hook your eyes up with those ocular field lenses! All in all, a very nicely operating classic compact Porro, and quite collectible even in the twenty-first century. It certainly puts a smile on my face every time I use it. Eventually I bequeathed it to a former student of mine, who has since become a keen birder and lives in the United States.

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The Opticron Dioptron 8×32 Classic Porro

The Opticron Dioptron 8×32 is an elegant instrument with wonderful optics and ergonomics

The next model I explored was a later dated instrument from the UK-founded Opticron optics firm. Called the Dioptron 8×32, it was manufactured in Japan and dates to the mid-1990s. Thus, it represents the next step in the intelligent design of the compact Porro prism binocular. I picked this model up for just £50 plus shipping. Though of slightly lower profile than the Zeiss Jenoptem, the Dioptron weighs roughly the same as its German counterpart  – under 500  g  – so it’s a very light weight field glass. The Japanese origin of the Dioptron is betrayed by the stamp on the front of the binocular, which unscrews to allow it to be mated to a tripod. The instrument also arrived well collimated, which flies in the face of those who insist that Porro prism designs are much more susceptible to misalignment than their roof prism counterparts. If you mistreat any binocular, you’re in for trouble. But treat them well and they will serve you for a lifetime. The objectives show a very prominent blue anti-reflection coating, unlike the prominent purple hue on the Jenoptem objectives. I’ve learned to expect a yellowing of the image, and that’s what my observations confirmed after I had looked through it. The big difference between this model and the Zeiss Jenoptem is the focus wheel. In a departure to classic German compact binoculars, the Dioptron focus wheel is much larger and easier to access than that of the Jenoptem. Even after all these years, it works like a dream. Very high quality indeed!

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Check out the prominent blue anti-reflection coatings on the Dioptron objective lenses

When the Dioptron first arrived, I had not really examined its interior thoroughly enough to see whether or not it needed cleaning. However, after carefully examining its innards in good light, I was surprised to see that it did have a thin veil of haze and the beginnings of a fungal infestation which fell below my radar. So, I decided to get it professionally cleaned. I phoned Tony Kay at Optrep, who had done a great job cleaning up my Nikon E 10×35 WF (discussed later in the chapter), and asked him if he’d be willing to clean up the little Opticron Dioptron. He said yes and gave me a very reasonable quote. So off it went to his workshop in Selsey- the home of the late Sir Patrick Moore – on the English south coast. A couple of weeks later, I got it back, all cleaned up and looking like new. The optics were de-stained, cleaned, set and collimated. The hinges of the instrument were also freed – all ready to enjoy a new lease of life. All that remained was to give it a good clean with an Armor All wipe to condition the soft rubber eyecups and the chassis leatherette. The view was terrific: very wide (8.25 degrees), bright, extremely sharp with a great big sweet spot. It was a little brighter than I remembered it prior to dispatching. The slight yellow tint was still there though; a common feature of good optical glass from this era. There was also a bit of glare when pointed towards strongly backlit scenes but I felt it was perfectly acceptable. All in all, I was thrilled with its performance after I spent the afternoon glassing birds at two of my local patches. Here, I’d like to flesh out some more details concerning its ergonomic and optical design, as well as disclosing more information about other incarnations of this instrument I’ve discovered since first acquiring it last year.

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This has got to be one of the lightest and smallest 8×32s in existence, weighing in at 494  g without the strap  – that’s 10% lighter than the Nikon E II 8×30 and almost as lightweight as the Nikon Monarch HG 8×30 high-performance roof prism binocular. The diopter compensation ring, located under the right ocular lens has clearly delineated markings to quickly enable the user to set and remember his/her desired settings. However, it does tend to move, but that was easily remedied by affixing a very tightly fitting o ring around the bottom of the eyepiece that increases the frictional torque considerably. Since doing this, I’m delighted to say that the diopter setting hasn’t budged a millimeter. What’s more, it’s nicely color-matched with the rest of the chassis so you’d hardly notice it’s there unless you point it out.

A tight-fitting o ring all but stops the diopter wandering while in field use

The eyecups give some eye relief but not a great deal. You can better access the field with glasses on by folding them down but even so, it’s difficult to engage with the entire field. That said, I had absolutely no problem seeing the entire field without glasses, even with the rubber cups extended. The central focus wheel is much larger and considerably faster than most other instruments I’ve used. Just half a turn clockwise brings you from closest focus – measured at 2.56 m – all the way to infinity and a little bit beyond. The chassis is mostly composed of high-quality machined aluminum with only a few plastic and rubber parts found on the bridge and around the objectives. Having rubber surrounding the objectives is a good move as it won’t scuff the paintwork like it does on my metal-rimmed Nikon E objectives. And unlike my Nikon E II 8×30, which cannot reliably stand upright on a flat surface, the Opticron Dioptron can!

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The instrument feels great in my medium-sized hands. The leatherette provides excellent grip and there is ample room for your fingers to engage with the focus wheel, either from the top or, indeed, from the bottom. It has a beautiful, high-­ quality feel about it. Indeed, you instantly get the feeling you’re handling a durable, high quality optical instrument. The Dioptron  is fully multicoated with the best coatings available at the time. The objectives have a strong blue tint in broad daylight, while the eye lenses display a purple-green bloom. Coatings have improved somewhat from the 1990s, but the ones applied to this instrument are more than adequate for use in most lighting situations, but maybe not my first choice on dull winter days or at dawn and dusk, where newer coating technologies clearly excel over older treatments. The Dioptron shows some internal reflections when pointed at a bright streetlight but they are fairly weak and not especially consequential. The exit pupils look good with minimal levels of peripheral light around them. Optically, the view is very impressive; sharp, nice contrast, and in possession of a large sweet spot. The instrument shows some mild pincushion distortion and field curvature out near the field stops as well as lateral color. The field stops are beautifully delineated in the Dioptron, something I’ve really come to appreciate in binocular optics. This nifty little 8×32 Porro delivers terrific 3D impressions of the landscape, a feature that continues to endear these instruments to me. Comparing the Dioptron to the Nikon E II 8×30, I judged their central sharpness to be very comparable. The latter serves up a brighter image with more contrast though and its superior coatings were better at suppressing glare. The Nikon E II has a noticeably wider field – 8.8 degrees versus 8.25 degrees – too but the Dioptron is plenty wide enough for most applications. In addition, the Nikon E II has a significantly better close focus than the Dioptron (1.96 m versus 2.56 m). I really like the focuser on the Dioptron. It’s super smooth, gliding with all the gracefulness of the innards of a Swiss watch. Images snap to an absolute focus with no ambiguity. This renders it an excellent birding glass in good light. As the light fades however, in the evening, the superior light transmission of the Nikon glass is easy to see. The images are significantly brighter. Again, these comparative tests are not meant to portray the Dioptron in a negative light, only to show how it’s a product of its time. Optical coatings have improved quite a bit since the 1990s and the Nikon has some of the very best available. As soon as it arrived back from its restoration, I took it off for a saunter to one of my local patches. I was lucky enough to register my first sighting this season of a group of Swallows. At first, I was overjoyed to see just one, its distinctive fork tail gleaming in weak Spring sunshine, perched high in the trees near Culcreuch Pond, resting from its long sojourn from North Africa. But as I scanned the high branches of a few other trees in the vicinity, I caught sight of several others. Some of them took to flight, flying low over the fields with breakneck speed. What a thrill! On another occasion, I brought both the Dioptron and my small Zeiss Terrra ED 8×25 pocket binocular into the west end of Glasgow to visit my in-laws and to do a spot of urban birding. I’m glad I brought both along, because it gave me an opportunity to compare the instruments. The Zeiss is a nice pocket glass to be sure, but it can

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never approach the huge step-up in performance of a high-class 8×30. Size-wise, there’s not an enormous difference between these instruments either – both could pass as pocket binoculars – but from a performance point of view, the Zeiss didn’t even come close! When the Dioptron was first marketed in the UK, it commanded a price tag of about £120 back in the early 1990s. But there’s an interesting twist to the story of the Dioptron. Phil Grimsey informed me that he had acquired a Japanese-made 8×32 from a charity shop going under the name of Panorama Puma. The chassis was identical to the Dioptron as were the antireflection coatings applied. This suggests the instrument was rebadged under several names and was not exclusively developed by Opticron. That said, Phil is also chuffed to bits with his own lucky acquisition.

A Dioptron Dead Ringer: The Japanese-made Panorama Puma 8×32. (Image Credit: Phil Grimsey)

Both the Carl Zeiss Jenoptem and the Opticron Dioptron classics can be enjoyed entirely on their own terms. I’ve taken both instruments out on long walks in the countryside and have thoroughly enjoyed the lovely large fields of view and very large sweet spots, as well as the characteristic 3D pop they both command. The worst of the glare is seen when these instruments are pointed near bright light sources, but a lot of this can be removed simply by shading the objectives with your hands. Both instruments helped me to finally make the transition to using high quality Porros in preference to roof prism models when using compact binoculars in the field. The transition feels entirely natural for me. After all, I’m a dyed-in-the-wool classicist don’t you know!

A Couple of Great Modern Classics from Nikon

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A Couple of Great Modern Classics from Nikon

The excellent Nikon E 10×35 WF

The reader will already be aware of my great affection for the Nikon E II 8×30. From the moment I put it to my eyes, I was stunned by the magnificent views it served up: a wonderful, tack sharp, ultra-wide view, rich in contrast and detail, and all with an enchanting 3-dimensionality. That experience got me curious about other small Nikon Porros and I became intensely interested in the now discontinued E series, especially after reading glowing reports on the Nikon E 8×30. I decided to bite the bullet and purchased a used Nikon E 10×35 WF from a seller based in Tokyo, Japan. The seller stated that the instrument was in good condition, with no fungus and a small amount of dust that had made its way inside the instrument. Checking the serial number, I was relieved to see that it was one of the later, multi-coated models, which were manufactured between 1988 and 1998, after which time Nikon introduced their latest, greatest small Porros – the venerable E IIs and SEs. Judging by the numbering – 611675 – I guessed that it was made in the mid -1990s. It took just a week for it to travel from the Far East to my home here in rural central Scotland, and I was very excited about the prospects of holding the instrument in my hands. The binocular was exceptionally well packed, taking what I felt was an eternity to remove all the bubble wrap before I could finally hold it! Straight from the get-go I was extremely impressed with the instrument, coming only with a neck strap of extremely high quality. The instrument looked very lightly used, with

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no significant scuff marks on the body. I could instantly tell that this instrument was made during an era where craftmanship was at a much higher level than it is today; the beautiful contouring of the solid metal chassis, overlaid by an immaculately applied retro leatherette armoring. As one reviewer noted, you simply don’t get instruments made to these standards today! I was relieved to see that the instrument arrived in excellent collimation. The exit pupils were nice and round, with very little extraneous light around them. Performing my Iphone torch test showed no significant internal reflections, diffused light or diffraction spikes, all characteristic of a well-executed Porro prism design. But I hit a snag when I examined the interior of the binocular from the objective end. Yes, there was a small amount of dust visible on the prisms, a very thin veneer of haze, but also significant fungal growth on the prisms of both barrels – something I was assured was not present by the Tokyo seller. Fortunately, the fungal growth and dust didn’t significantly compromise the view. How was it? This a good step up in quality from the classic Zeiss 8×30s. Compared with my late 1980s multicoated Zeiss Jenoptem 8×30, the Nikon view was indeed much better. 10× in a very well corrected 6.6-degree field offers a unique perspective; at least from my own experiences. Brightness, contrast, glare suppression and sharpness were all very good in this modern classic. And just like my smaller E II, the view is supremely comfortable, with no problems with eye placement and zero issues with blackouts. In the wee small hours of the morning of September 6, I enjoyed sumptuous views of the Hyades in Taurus and right above it, fiery red Mars and the Pleiades. 10× has been my personal favorite magnification for stargazing of late. It just goes that little bit deeper than an 8× equivalent. I was very impressed by the Nikon E 10×35’s wide field of view, with pinpoint stars across most of the field. Near the field stops, you can readily make out some field curvature, which can be focused out to some degree. Moving higher into the sky, the Nikon E served up excellent views of the early autumn Milky Way through Cygnus, Cassiopeia and Perseus. Views of the Double Cluster were also highly captivating, following the curving chain of stars northwards to commune with the lovely starry patch, Stock 2. I enjoyed one more day with the Nikon E 10×35, taking it up to one of my local patches – Culcreuch Pond – where I enjoyed some great views of Mute Swan cygnets learning how to fly. It’s all about mimicry. The adult directs the cygnets to one end of the pond, then takes to flight, keeping low above the water. The cygnets began flapping their wings frantically but as yet, they had not mastered the power of the air. I was also lucky enough to watch a magnificent Red Kite circling over the newly cut hay in a nearby field, the 10× glass showing some nice details quite invisible to an 8× equivalent. Close focus was measured to be 3.7 yards – plenty close enough for the vast majority of birding activities. It was during such a time that I thought about what I’d do about this very good modern classic, and I decided on getting it professionally serviced by skilled experts. I wanted to have the fungus removed from the prisms and the optics thoroughly cleansed so that it would enjoy a new lease of life. Once again, Tony Kay, technical director of OPTREP, would refurbish it for me. So I fetched my leatherette pouch that came with my Nikon E II 8×30, which also proved to be a snug fit for the larger 10×35 glass, packing it away

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in a small box with plenty of bubble wrap. The next day, September 7 2022, it was winging its way to his workshop. On Saturday September 24 the instrument arrived back safely from its journey to the English south coast. I’m happy to report that the Nikon E 10×35 was thoroughly cleaned internally, with no sign of fungus, haze or dust inside the barrels. Collimation was perfect also. I was keen to do more glassing with my newly restored Nikon E 10×35 and took it along with me to one of my local patches. From the moment I put it up to my eyes I was very impressed with the quality of the images delivered by this instrument, now approaching 30 years of age. Homing in on a young Cormorant perched on a fallen tree, the image was very sharp both on-axis and off axis. The contrast is very good; not quite in the same league as a top roof prism binocular but not far off either. The focus wheel was still on the stiff side but it’s less critical in a 10× glass as you’re less likely to use it to follow fast moving targets. I also found that folding down the rubber eyecups enabled me to better engage with the field and to clearly see the field stops. The instrument feels lovely to hold in the hand; one of the nicest I’ve experienced, the leatherette armoring affording excellent grip. I spent a half hour watching familiar water birds at the pond: noisy Mallards, a male Tufted Duck and charming Moorhens. On another afternoon, I was lucky enough to get one of my best views of a gorgeous Kingfisher arrayed in its beautiful blue plumage and I appreciated the extra reach of a 10× glass over my standard 8× birding binoculars. And while time has marched on since these high-quality Nikon classics were made, its field of view is still impressively wide even by modern standards. 6.6 degrees at 10× is a great place to be, especially in an elegant, lightweight binocular such as this. During a forest stroll in early winter, the Nikon E 10×35 served up some excellent views of the treescape now denuded of leaves after several autumn storms. This is where the marvelous three-dimensional views of high power Porro prism binoculars really come into their own. Every little detail of the tree trunks, rain-drenched moss glistening in weak December sunlight, the delicate texture of the wood grain all stood out as though I could touch it with an outstretched hand. Of course, many are quick to point out that these classic Nikon glasses are not waterproof, but I think we’ve became far too timorous about this. You’d be forgiven for thinking that birding only began as soon as soon as waterproof and fog proof instruments became available. Nothing could be further from the truth, of course. Many seasoned birders just got on with things for decades before these innovations were even dreamt up! My exchanges on Birdforum on the alleged weakness of the Nikon E Porros regarding not being waterproof or fog proof, left me puzzled. I asked what I felt was a completely legitimate question: “What did folk do before the advent of full waterproofing and nitrogen gas purging?” Were there no birders before Steiner introduced the first fog proof binocular back in 1973? The response I got was rather telling. Only a single person eventually gave an answer of sorts, which indicated to me that not a great deal of thought was put into this issue. Instead, I got rather glib responses like, “folk moved with the times and just bought waterproof instruments.” That wasn’t good enough for me. Several

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generations of birders got on just fine before such an issue was “solved.” I perceived an altogether timorous culture of individuals who simply bought into the ‘roof prism solution.’ So how did they do it? And more importantly, what could I do about it? I wanted to find workable solutions. And this led me to initiate an investigation into how effective simple, interventive measures could make to keeping such instruments fog free, both internally and externally, while glassing in cold and damp conditions. My first approach was to construct proper storage containers for my non-waterproof Nikons. Theses comprised of simple Tupperware plastic containers filled with silica gel desiccant that were both air and watertight. You can see one such arrangement in the photograph below:

Tupperware containers laden with silica gel desiccant will keep your non-waterproof binoculars bone dry

My plan was to simply leave the empty box in a cool, dry, unheated outhouse before venturing out into the cold and humid air. Such an outhouse would be at most just a couple of degrees higher than the outside air. I would wear gloves to minimise the transfer of heat from my hands to the Magnesium alloy chassis of the binoculars. And immediately after my return from my glassing excursions, I would then place the instruments inside their containers before bringing them into a cool back lobby. Then, after a spell there, I would return them to room temperature. Taking advantage of a cold snap, which would endure for at least a few weeks from the beginning of December 2022, I began daily experiments, taking some

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notes on ambient temperature, wind speed and humidity, as well as the duration of my walks. The reader will note that I did not use any anti-fogging agent during the course of these experiments. This two-week+-long study, conducted over a long cold spell, as well as some drizzly days showed that these non-waterproof Porro prism binoculars fare just fine, so long as some simple interventive measures are set in place like wearing gloves when the temperatures are low, and returning the instruments slowly to ambient temperature once returned to their desiccant filled Tupperware containers. Some fogging of the ocular lenses tends to occur on colder days with reduced wind, but that’s exactly the same for waterproof roof prism binoculars, as my parallel experiences attest to. After these experiments were conducted, it occurred to me that a small binocular like the Nikon E 10×35 WF and my smaller 8×30 Porros being stored in a water and airtight Tupperware container with desiccant at room temperature will allow efficient diffusion of gases. The container has 20 sachets each containing 10 g of activated silica gel. This desiccant can absorb up to a third of its own weight in surface water and can be re-activated by placing it in an oven at 125–200°  C for a few minutes. That amount of desiccant ought to create a strong concentration gradient for the net diffusion of a small molecule like water vapor (molecular weight 18 which is considerably smaller than the average molecular weight of air) out of the inside of the binocular. Such a long-term storage strategy ought to thoroughly dehydrate the air in the interior of the instrument. And if that were true, I reasoned, it wouldn’t matter if I treated the binocular like any waterproof, nitrogen-gas-filled roof prism instrument. It should not fog up internally under any conditions so long as I kept to this storage routine. I tested this hypothesis in early 2023, by subjecting these binoculars to several hour-log exposures in cold, high humidity weather before bringing them straight inside to a warm living room and watching what happened. I also included a control in these experiments, that is, a non-waterproof binocular not stored in a desiccant-­ filled Tupperware container. I can disclose that only the outside lenses fogged up after being brought in from the cold in this way but did not fog up internally. The control binocular, in contrast, did fog up both inside and outside. Eureka! My non-­ waterproof Porros were now effectively fog proof. Furthermore, so long as I returned them to their desiccant-filled containers, they remained effectively fog proof! Moreover, this will work anywhere on Earth. For example, if you want to take your favorite Porro to a steaming hot jungle, you can create a makeshift container in situ for it so that it can keep moisture out of the interior of the binocular. The Nikon E series also includes a lower power 7×35 instrument that many binocular enthusiasts still enjoy using for its sharp optics and great field depth.

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 n Extraordinary Nikon Action 7×35 Widefield A from the Mid-1980s

A mid-1980s Nikon Action 7×35 package

I knew and read about some classic Porro prism binoculars from yesteryear that sported enormous fields, sometimes up to 13 degrees or more, but I wondered whether their edge of field performance would also let them down. So I began looking at classic Nikon Porros that offered something of a compromise and 9.3 degrees seemed to fit the bill the best. I’d lose a little magnification but gain a whole half a degree over my Nikon E II. But which model to choose? Having never tested any of these out in real life, it was somewhat of a guessing game, but I had to start somewhere. The condition of the instrument ranked high on my list of priorities too. I wanted an instrument that was in good condition, with no large build up of internal haze on the prisms or, worse still, fungus. Did such an instrument exist? The answer, I’m delighted to say, is yes! While browsing on eBay, I came across a very intriguing instrument. This was a Japanese-made 7×35 Widefield 9.3-degree binocular in what looked like excellent working condition. It even had the original eyepiece and objective caps as well as the black bonded leather case – Japanese made also. And it was going for £85 inclusive of free delivery! The seller had the presence of mind to include some photos taken through the objective lenses against a plain white background, which allowed me to assess the condition of the interior lenses and prisms. It looked amazingly good for the age, which the seller informed me dated to the mid-1980s. So I pulled the trigger and sure enough it arrived 2 days later. Opening the package, I removed

An Extraordinary Nikon Action 7×35 Widefield from the Mid-1980s

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the case from the wrapping to find the instrument perfectly positioned inside. When I picked it up, I was quite taken aback by its rather large frame. This was a longer-­ barreled binocular than I expected any 35 mm Porro to be.

The Nikon Action 7×35 has large prisms

Upon inspection with a flashlight I confirmed that the innards of the instrument were indeed pristine. How on Earth could a binocular that first saw light when I was a middle schoolboy still look so good after all these years? Well, the excellent condition of the chassis – with a couple of minor scuffs on the metal rims on the instrument’s mid-section– and the fact that it still had its original caps and no internal haze suggested to me that it must have been very lightly used. But it must also have been stored in a good, dry place to prevent the growth of internal fungus. The instrument is fully coated – most probably using a single layer of MgF2 on all optical surfaces. Thus, I fully expected that it would not be nearly as bright as instruments treated to a full modern multicoating. More on this later. Unlike the later E series, the focus wheel, which also appears to be made of some kind of tough plastic, is much larger and placed right between the barrels. It was a bit stiff coming right out of the cold box, which had travelled the length of the country from the seller, but after I ‘thawed’ it out, as it were, it came back to life moving smoothly in both clockwise and counterclockwise directions, with no free play or backlash. Splendid! The eyepiece housings appear to be made of some kind of tough plastic too, as were the rim of the objective barrels, which surprised me. The eyecups are made from rubber though, a significant departure from the hard plastic of the old classic

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Zeiss Porros. The diopter ring is very similar to that of my Nikon 10×35 E, which has a tendency to wander while in field use, but I soon remedied that by fitting a very tight rubber o ring immediately under it which keeps it in place much better. The chassis is ‘armored’ in an attractive, textured leatherette which is very nice to the touch as well as to visually inspect. Despite it being a big glass for a 35 mm format, I was surprised that it tipped the scales at only 665 g – much lighter than the Action EX and also lighter than the Aculon 7×35! The only disappointment with the instrument was a somewhat frayed neck strap, which I might have got by with, at least for a while. But having taken a short stroll with it, paranoia got the better of me, and I decided to replace it with a nice, old fashioned leather lanyard which supports its moderate weight well. The handling of this instrument is superb. I can wrap my hands round those curves in the mid-section with wonderful ease and comfort, using my middle fingers to fall naturally on the deeply ridged focus wheel. Less than half a turn clockwise brings you from closest focus (measured at 4.1 yards) to a little bit beyond infinity. All in all, this instrument, which has travelled nearly 40 trips around the Sun since it saw first light, is an ergonomic delight! Bravo! After about an hour of warming the instrument up to room temperature, I noted that all was well. The optics were clear both internally and externally. And it was at this moment that I brought it outside for a gander. Wow! This thing is super sharp! But what really impressed me was how big the sweet spot was: it was in a totally different league to the Nikon Aculon or the Action EX, which always gave me that funny goldfish bowl feeling as soon as my eyes drifted to the periphery of the field. No, this instrument was optically far superior to those other Nikon’s both on axis and especially off axis. Pure, indulgent pleasure! Glare was surprisingly well suppressed for a singly coated optic like this; far better, for example, than my multi-­ coated Zeiss Jenoptem from the same era. It has a slight yellowish color cast, very much like that achieved by a very mild photographic warm-up filter. Both longitudinal and lateral color correction are very well controlled. Hardly any was seen even on the most difficult high-contrast targets. Barrell distortion is mild. My first stroll with the binocular was during dull, overcast conditions. I brought it to one of my local patches, where a fallen tree occupies the far end of a pond. I’ve come to use this to judge how big the sweet spot is in many binoculars I test because it crosses the entire field. I could immediately see that its optical behavior was much more like that of my Nikon E II 8×30 than either the Aculon or Action EX models. Far superior off axis performance, with the sharpness being maintained nearly right to the edge. Vertical correction was not as good though, but that’s true even with my Nikon E II 8×30 and virtually all others I’ve tested. My next tests took place in brilliant winter sunshine, on the afternoons of both January 25 and 26. The views in this fabulous light were breath-taking. I could see details on the far hills that simply didn’t stand out in my tests with the Aculon and Action Ex. I quickly came to realize how little refocusing I was doing owing to the instrument’s impressive depth of field. The focus is a little stiffer than a top-rated birding binocular, but this turned out to be largely immaterial, owing to the generous field depth. I’m really coming round to appreciating this wonderful optical

An Extraordinary Nikon Action 7×35 Widefield from the Mid-1980s

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property! In bright sunlight, one hardly notices the slight yellow tint of the old Nikon Widefield 7×35, but as the light fades more tests conducted with my Nikon E II showed up the clear advantages of modern broadband multi-coatings. Venturing out just before sunset on a cold and cloudless late January day, I glassed some tree trunks about 80 yards in the distance. Comparing the images side by side, I could see that the Nikon E II 8×30 was already pulling ahead of the old classic. It had an unquestionably brighter image and better contrast between the browns of the tree bark and the green moss and lichen mottling its surface. In yet another test, carried out in the early evening of January 26 2023, I mounted both instruments on a tripod and studied the images of a beautiful crescent Moon sinking towards the western horizon. Apart from more internal reflections in the 7×35 I was genuinely impressed by how comparable the images were. The Moon had a very faint fawn tint to it that I didn’t really find distracting, comparing it with the marble white color served up by the Nikon E II 8×30. Color correction was actually better on the Nikon Widefield 7×35 than the E II, both on and off axis. I would estimate its sweet spot is a good 70% or 75% of the field, about the same, in fact, as the 8×30. Illumination drop off was a bit more pronounced on the 7×35 though, but the effects of mild field curvature near the field stops could be easily focused out – just like the venerable E II. Venturing out after midnight in the wee small hours of January 26 2023, the Moon had set and the full glory of the winter night sky was presented to me. Cassiopeia, Perseus and Taurus were now hanging low on the north-western sky, Gemini was near the meridian and brilliant Arcturus was rising fast in the east. I enjoyed fabulous views of the Hyades and Pleiades. Framing the Auriga Messier open cluster trio in the enormous 9.3-degree field proved child’s play. I swept up the Beehive cluster in Cancer, and looking eastward I enjoyed some marvelous views of the Coma Berenices Cluster. Stars were beautiful pinpoints across most the field of view, with only slight distortion seen on the brighter stellar luminaries near the field stops. Despite its lower overall light transmission, this is a better glass than the Aculon or Action EX 7×35s for stargazing. What it lacks in light gathering power is easily offset by its better corrected field of view. I was reminded of how charming a good wide angle 7×35 can be on the evening of January 28 2023. With a first quarter Moon in the sky, I located Kochab, a 2nd magnitude red giant star in the Little Dipper and placed it at the bottom of the Nikon Action 7×35 field of view. And there at the top of the same field I spied the bright Comet 2022 E as a faint fuzzy. I estimated their angular separation at the time to be 7.5 degrees. This is the brightest comet I’ve seen since Comet NeoWise graced our skies. After I had received the instrument and done some preliminary testing, I did a search to see if others had reviewed the Nikon 7×35 Widefield 9.3. My searches came up empty at first, as all I got was a number eBay links here and there showing some photos of the instruments for sale. Puzzled I began to read older threads on past Nikon Porro prism binoculars and eventually hit on the issue: this model was apparently known as the Nikon Action 7×35. What’s more, there were apparently several incarnations of the Action, with the later models being switched to production in China. What nailed it for me was finding a very interesting post on Birdforum

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dating to January 2012 made by Henry Link, an experienced US-based binocular enthusiast who discussed the same model. What’s more, he came to largely the same conclusions about this binocular as I did: a Mark1 Nikon Action 7×35 Widefield. Furthermore, in his post he described the results of tests of this binocular, concluding that it was one of the sharpest shooters in its genre. It was, in his own words, “as good as it gets.” Link also provided a really good explanation for why the Action Mark I worked so well. It has a longer than average focal length – a full 120 mm in fact – making it a slower f/4 optical system. Increasing the F ratio of any telescopic system is a way to reduce all geometric (Seidel) aberrations as well as chromatic aberration. I contacted Henry to tell my story with a few photos of the instrument. He confirmed that it was the original Nikon Action as described. Moreover, in subsequent forum discussions, Link revealed that the original Action 7×35 used a better corrected 4 element Konig eyepiece, unlike the 3 element designs of the later Nikon E and E II series. In his opinion, the Action had better axial aberration correction than the former. All, of this, of course, was music to my ears! What a marvelous find! To say that I’m delighted with it would be an understatement. This is a higher-class binocular than anything Nikon is currently churning out in the 7×35 format. But it raises as many questions as it answers. Why give up on such a great optical design? Can it be resurrected? It’s also taught me a valuable lesson; there is nothing new under the Sun and great optics can be had from pretty much any era if you’re lucky enough to stumble on them! Later in the Spring of 2023, I discovered that the Nikon Action 7×35 is the ideal instrument for watching the extraordinary aeronautical displays of fast-moving Swallows returning from North Africa where they spent the winter. Its extremely large and well corrected field of view makes following these extraordinary birds more east to track. And while 9.3 degrees is very generous indeed, I sometimes hankered other classic Porros with even wider fields of view. Can you imagine how much fun you could have with an instrument sporting an 11- or 13-degree field? More generally, the 7×35 is a greatly underrated format which has many things going for it: decent light grasp, stable magnification for handholding, a very wide field of view and a large exit pupil of 5 mm. I think of all the formats set to make a comeback the 7×35 must be.

A Classic Astronomy Binocular from Takahashi Classic binoculars come in all shapes and forms. One of the most lauded and sought after binoculars for the ardent binocular stargazer is the Takahashi Astronomer 22×60. This legendary instrument consists of two f/6 fluorite refractors mounted in binocular mode. The reason that the Takahashi Astronomer looks as if someone stuck a pair of small telescopes on the front end of a regular binocular is because that’s essentially what happened. But these are no ordinary telescopes; they are the four-element fluorite objectives from Takahashi’s premium 60-mm f/5.9

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refractor – the FS-60C. This prestigious lineage puts an unusual spin on the binocular. In the arena of expensive astronomical gear, a binocular with mere 60-mm objectives would hardly seem like a major player, but most amateurs would agree that the idea of viewing the heavens with a pair of Takahashi FS-60C refractors has considerable merit.

The Takahashi Astronomer 22×60. (Image Credit: Dean Davidson)

The back end of the Takahashi Astronomer appears to be a standard, albeit rather rugged, Porro-prism binocular made for 60-mm objectives. The prisms are sufficiently large to illuminate the entire field without vignetting, even at the field stops. A conventional central hinge arrangement allows the interocular distance to be adjusted from about 50 to 75  mm, so the smallest faces can view comfortably through it. Eye relief for the individual-focus eyepieces is a generous 18 mm, which should comfortably accommodate most people who wear eyeglasses viewing through the instrument. Close focus of the Takahashi Astronomer is stated to be about 43 meters. The Takahashi Astronomer binocular offers individual-focus eyepieces that maintain sharp stars, even with pressure against them. The field of view is slightly over 2 degrees, and stars are pinpointed for about four-fifths of its diameter, becoming slightly soft at the outer edges but not distorted. The binocular’s twin optical tube assemblies have star maps  beautifully embossed on their exterior. Although there is some falloff of the image towards the edge, it is minor and comparable to some of the best flat field optics available. The binocular has a minute amount of

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pincushion distortion, which can reduce the “rolling” effect when panning and is sometimes intentionally engineered into  the optics. It is also useful for daytime observations of distant targets and is particularly adept at viewing smaller deep sky objects such as the Pleaides, Messier open clusters, the Orion Nebula, and the Trapezium at its center. However, its field of view is smaller than the industry norm at 2.1 degrees, and it lacks angled 45- or 90-degree eyepieces for more comfortable nighttime viewing. Despite being discontinued, the Takahashi Astronomer is still available for purchase online, often fetching prices as high as $2000.

A Blast from the Past: Swift Audubon Porro Prism Binoculars Swift Instruments was founded by Edward G. Swift, a former employee of Bausch & Lomb. The company initially produced microscopes, but in the early 1930s, they expanded into the production of binoculars. In 1933, Swift introduced their first binoculars, which were well-received by the market. Over the years, the company continued to refine and improve their binoculars, and in 1965, they introduced the Swift Audubon Porro prism binoculars. These beautifully crafted instruments were designed specifically for bird watching and nature observation. They were named after John James Audubon, the famous ornithologist who is known for his detailed illustrations of North American birds. The binoculars were designed to provide a clear and accurate view of birds and other wildlife, with superior image clarity and color fidelity. The Swift Audubon Porro prism binoculars were a significant improvement over previous models on the market. They featured high-quality optics, with lenses made from high-quality glass and coated with multiple layers of anti-reflective coatings to reduce glare and enhance contrast. The binoculars also had a wide field of view and long eye relief, making them comfortable to use for extended periods. Over the years, the Swift Audubon Porro prism binoculars continued to evolve and improve. In the 1980s, the company introduced new models with waterproof and fog-proof construction, making them more durable and suitable for use in all weather conditions. In the 1990s, Swift Instruments was acquired by Meade Instruments, which continued to produce the Swift Audubon Porro prism binoculars under the Meade brand. Today, Swift Audubon Porro prism binoculars are still popular among birders and wildlife enthusiasts around the world. They are known for their high-quality optics, comfortable design, and durability, making them an excellent investment for anyone who wants to enjoy the natural world in all its beauty and detail. I canvassed the opinion of binocular enthusiast and Audubon collector, Paul Wehr from New York. Here’s what he had to say about each of the models.

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Is there a collective noun for a group of Swift Audubon 8.5×44s? (Image Credit: Paul Wehr)

“The iconic and superlative Swift Audubon 8.5×44 Porro prism binoculars were introduced by Swift Optics in the beginning of the 1960s. To many birders these were the premier birding binoculars for decades. The first iteration known as the Audubon 804 model was marketed in the early 1960s. Swift later became Swift Instruments inc. There was also a 10×50 version known as the Swift Audubon Kestrel 10×50 (model 826). Here we discuss the original the 8.5×44 models. When first introduced they were a milestone in binocular design, with an 8.5 magnification and 44  mm objective lenses. There were multiple models starting with the 804 in the 1960s, all the way to the early 2000s and ending with the last production model, the 820 ED. The 820 line had a few variations and was remade into a rubberized water proof model. The 820’s had click adjustable eye cups to adjust eye relief. Two versions were available at the same time, a standard version and an improved ED version which would help reduce chromatic aberration. The ED version was of course the most expensive and not necessarily the best, IMO. We’ll discuss the last model in more detail a little later. Although not advertised there seems to be some agreement that the early models initial ocular design was a 5 element Erfle and BaK4 prisms designed by Tamron Optical and manufactured in Japan. Field of view on the first 804 (type 1a) model was 8 degrees, which at the time was considered quite large for an 8.5 magnification. All other 804 models starting from the type 1b had a field of view of 8.5 degrees. These binoculars were heavy at approximately 1077  g and built extremely well and made to last. There were a few 804 models. A breakdown of Audubon models are as follows: 804: The introduction: these went through some minor optical coating changes throughout their production, many changes were cosmetic and rebadged, possibly for different markets. Whether they were marked MKII or Wide Field, they were essentially the same binocular. All 804 Audubon models were known as the large version and usually and ironically marked featherweight. The later 804R and HR5 models were known as the small Audubon, also known as type 4. All dates are approximate, some newer models overlap earlier models in the lineups.

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804 type 1a 1960–1963 made by Tamron optical JL E45, Single coated, 1077 g, field of view 8 degrees. 804 type 1b 1964–1967 made by Tamron optical, JL E45, Single coated, 1077 g, field 8.5 degrees. 804 type 1c 1968–1970 made by Tamron optical, JL E45, some marked coated and others marked fully coated, 1077 g, field of view 8.5 degrees. 804 type 2a 1971–1979 made by Hioshi Kogaku JL B56, fully coated, 38 ounces, FOV 445. Focuser position and style was changed from a central long barrel type on the hinge to a smaller wheel style on the ocular bridge. 804 type 2b 1980–1984 made by Hioshi Kogaku JL B56, fully coated, 1077 g, field of view 8.5 degrees. Other than markings and a few possible minor changes to slotted prisms. 804 type 3a, 3b and 3c dates are a little confusing on these three but they may have run concurrent with earlier models up until 1984. These were made by Hioshi Kogaku JL B56, fully coated fully coated,1077 g; all had a long barrel type focuser and positioned on the hinge. 804R type 4a (R standing for revised), 1985–1989, made by Hioshi Kogaku JL B56 new lighter design weighing approximately 822 g, multicoated, field of view 8.2 degrees. Focuser between the hinge. Eye relief was increased from 13 mm on the older models to 14 mm. 805R/HR5 type 4b 1989–2000 made by Hioshi Kogaku JL B56 29 ounces, Filed of view 8.2 degrees. Focuser between the hinge, eye relief was14 mm. The HR5 could mean high resolution 5 element. These are marked with a gold medallion on the right barrel. There were two models, one marked multicoated and a fully multicoated version. Some might disagree but, in my opinion, these two are the best of all the Audubon 804R/HR5 and later introduced 820’s models. To me these offer the best combination and compromise in resolution, sharpness, control of chromatic aberration and edge clarity. The largest sweet spot and most gradual edge fall off of every model before or after. The Audubon 804R/HR5 MC and FMC are my absolute favorite Audubon binoculars. 804R/HR5 ED type 4c 1992–2000 made by Hioshi Kogaku JL B56 822 g, field of view 8.2 degrees. Focuser between the hinges. These have the gold medallion on the barrel, ED in red lettering on the prism cover, as well as a red band on the objective rubber safety ring. These models incorporate an extra low dispersion air spaced objective lens to help with better control of chromatic aberration and resolution. There really doesn’t seem to be much of a bump in either area, but the sweet spot is noticeably smaller and the edge fall off is inferior to the non-ED version. There is a very noticeable warmer (red/yellow) color hue to this model, very similar to many Nikon Porro and roof binoculars of the time. 820 and 820ED introduced around 2000. I have no information when production stopped. Both modernized rubberized armor and fully waterproof. I’m guessing this model’s optics were the same as the previous non water proof 804/HR5 ED model. I don’t see any difference optically between these two models. ED models: As mentioned earlier the later 804/HR5 and 820 ED models seems to have been an attempt to improve chromatic aberration control and possibly for

A Neo-Classical Roof Prism from Leica

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some other improvements that escapes me. Although a slight improvement in chromatic aberration can be noticed with a side-by-side comparison to the earlier 804R and 804R/HR5 models, it appears to have come with some other negative attributes to the field of view. The edge distortion is very evident and abrupt. The center is sharp and bright but starts to get a very blurry edge from almost 50% of the FOV to the edge. I believe that Swift may have been swayed to marking pressure to add an ED lens component that was not very well thought through to compete with other optics companies adding ED components to their products, but this is just a guess. The addition of this lens may not have worked well with the rest of the optical design. I have confirmed by testing multiple copies of the ED versions to convince myself this is or was not a sample variation issue and that it carries through the whole ED line.”

A Neo-Classical Roof Prism from Leica The German optics firm Leica produces some of the best binocular views in the industry, but they also have a penchant for re-creating celebrated products from the past. One such product is their Trinovid 7×35, a format that has almost gone extinct in recent years. Fellow binocular enthusiast and author, Holger Merlitz, offered his opinions on this beautiful new binocular from Leica.

The Leica Trinovid 7×35. (Image Credit: Holger Merlitz)

“This is a peculiar binocular in many respects, whereby its specialness already begins with the specification: 7×35 is an almost extinct format today, and wrongly so, in my opinion: The 7× magnification produces handheld a jitter-free image with

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a large depth of field, and the 35 mm objectives guarantee large exit pupils and thus an excellent twilight performance in combination with a relaxing ease of view. The Leica 7×35 Trinovid was modelled on the 7×35 B from the 1960s and 1970s and has therefore half-jokingly been dubbed the “Retrovid”. In fact, the similarities between the two generations are limited to the external appearance. Internally they differ in their prisms (Schmidt-Pechan instead of the Uppendahl) and the focussing mechanisms (focussing lens instead of the internal eyepiece focussing). Further, the new Trinovid uses adjustable (pull-up) eyecups instead of the former foldable rubber eyecups. The Trinovid shines with a very bright image and a Leica-typical high colour saturation. Outstanding is its suppression of stray-light, which is actually more effective than in most of the premium binoculars. The field of view is only moderately wide at 140 m/1000 m, and it lacks both the field-flattening lens which would provide a perfect edge-sharpness, and ED objectives to suppress the colour fringes. In this respect the optical design of this binocular is indeed retro, albeit in combination with state-of-the-art coating technology. Compared to modern 8×32 binoculars, this 7×35 is astonishingly compact, and with 570  g (without rainguard and carrying strap), it falls in the same weight class.

Easy on the Eye: the Leica ‘retro’ Trinovid 7×35. (Image Credit: Holger Merlitz)

With a price of 1500 euros, these binoculars are no bargain. The majority of semi-professional birders, who complain about the poor close-focus distance of 4 m, the slow focus wheel and the absence of fully waterproof sealings, will definitely find more suitable alternatives for less money. The nature lover, however, who wants a compact, optically and mechanically excellent binocular for unforgettable observation experiences, will certainly enjoy this little gem.”

A Well-Loved Classic from Zeiss: The 7×42 Dialyt

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A Well-Loved Classic from Zeiss: The 7×42 Dialyt Another highly-regarded glass no longer in production is the Zeiss 7×42 Dialyt. This instrument first hit the market back in 1981. Sporting a very relaxed 8.6-degree field, the Dialyt featured Abbe-Koenig roof prisms for enhanced light transmission. The earliest models (pre-1988), lacked phase correction, but thereafter Zeiss upgraded the Dialyt with their proprietary T*P* coating which do have phase corrected coatings. The T*PP logo appears as red lettering on the front end of the bridge. Though the instrument looks rather bulky with its deeply ridged rubber armoring, it actually weighs only 800 g. The view, according to some lucky owners, is excellent, pretty much indistinguishable from contemporary high-end roof prism binoculars. Light transmission is of the order of 86% very impressive for a classic instrument, though edge-of-field correction lags behind the best available today owing to the lack of field flattening lenses. Though the optics are sealed, it’s not nitrogen purged so some additional care must be taken if the user intends to use it in the rain and also storing the instrument.

The Zeiss Dialyt 7×42. Note the lack of the T*P* logo on the front of the bridge indicating a earlier, non-phase-coated model. (Image Credit: Holger Merlitz)

The anti-reflection coatings are the typical deep purple reminiscent of contemporary Zeiss Victory SF models. Despite its lack of extra-low dispersion glass, owners report very little chromatic aberration within its wide sweet spot, with only a trace seen on high contrast targets at the edge of the field. This could be attributed to the design of the Dialyt’s unusual focusing mechanism which, like conventional Porro prism designs, is external. This removes the need for an internal focusing lens which reduces color fringing. Another neat feature of the Zeiss Dialyt 7×42 is a scale built into the focus wheel which allows the user to mark the position of best focus for targets located at varying distance from the observer. Curiously, the non-phase

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coated, and later T*P* endowed models seem to fetch the same prices on the used market for about $700–$900.

From Russia with Love: A Classic Tento BPC 7×35 After enjoying a variety of classic Japanese and German Porro prism binoculars, I began to hanker after a classic Russian glass to explore their optical quality and ergonomics. Several names crossed my radar including Komz and Tento. That led me to do a search on eBay for instruments that might whet my appetite and it wasn’t long before I came across an intriguing Tento-branded 7×35. It was going for an unbelievably low price – just £25 plus £8 shipping. The unit looked to be in very good condition, with a clean interior and the seller assured me the optics were in good order. So I pulled the trigger and the instrument arrived just a few days later. Meanwhile I did some research on Tento, which I’ll briefly discuss next.

From the Soviet Era: a Zomz Tento BPC 7×35 (c 1988)

Tento is a Russian optical company that has a long and interesting history dating back to the Soviet era. The company was established in 1968 in the city of Kazan, which is in Tatarstan, Russia. Initially, Tento produced military optical equipment such as rangefinders, binoculars, and telescopes for the Soviet army. The company’s products were known for their high quality and reliability, and they were widely used by military personnel.

From Russia with Love: A Classic Tento BPC 7×35

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In the 1970s, Tento began producing binoculars for civilian use, and the brand quickly gained popularity among nature enthusiasts and hunters. The company’s binoculars were known for their excellent optics, robust construction, and resistance to extreme temperatures and humidity, making them ideal for use in harsh environments. In the 1990s, following the collapse of the Soviet Union, Tento faced many challenges, including a loss of funding and a decline in demand for military equipment. However, the company continued to produce binoculars and other optical instruments, and it gradually expanded its product range to include spotting scopes, night vision devices, and other specialized optical equipment. Today, Tento is still based in Kazan, and it continues to be a leading manufacturer of optical equipment in Russia. The company’s products are sold in Russia and in many other countries around the world, and they are highly regarded for their quality, durability, and affordability. The instrument arrived well packaged inside a soft case – not the original leather one. I didn’t mind however, as if all went well, I wouldn’t be storing it inside any conventional case. The binocular apparently was originally sold with orange filters, which would have been kind of groovy, but this one didn’t unfortunately. The instrument was manufactured in 1988, so near the end of the Soviet era, based on the small circle near the serial number found on the front end of the instrument. The binocular has a solid feel and has quite a bit of heft to it – 700 g in fact -but it handles very well. I’d definitely describe it as ‘Spartan.’ I was able to confirm that the optics were extremely clean with no fungus or haze inside the instrument. The instrument appears to be multicoated as far as I could tell, but looking at the objectives in daylight revealed a possible uncoated element somewhere in the optical train. The outer objective lens element also had a pale amber coating, a common feature, apparently, on many Russian binoculars from this era. The objectives are very deeply recessed however, conferring that extra bit of protection from the environment as well as stray light. The rubber eyecups looked in good condition, but I immediately treated them with some Armor All to protect them better. After looking through the instrument, I found I couldn’t see the field stops so I folded them down and hey presto – I could now engage with the entire field! The focus wheel is made from a tough plastic material, but I was really impressed with its smoothness. It’s very easy to turn and boy is it fast, taking less than one revolution to go from closest focus to infinity. The right eye diopter compensation is achieved by turning a ring under the right ocular lens. It moves smoothly and holds its position well. In a previous life as a telescope tester and reviewer, I spoke of my admiration for Russian optics in the form of the Tal 100R (Novosibirsk), a classic 4-inch f/10 achromatic glass which produced sharper images of the Moon and planets than a 4-inch TeleVue Genesis Fluorite F/5. I’ve also owned and enjoyed its larger sibling, the Tal 125R 5-inch F/8 refractor, so I was hoping that some of the same magic would rub off on this robustly designed binocular. I wasn’t disappointed! The optics for the BPC Tento 7×35 were provided by Zagorsk Optical-Mechanical Plant (Zomz), based at Sergiyew Posad, about seventy miles from the center of

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Moscow. It’s a classic Porro design with oversized, high-index BaK4 prisms delivering a very wide field of view (8.5 angular degrees). The exit pupils are perfectly round with no stray light or false pupils appearing in either of the barrels. Eye relief is quite generous for an older glass like this. I was able to see most of the field with my eyeglasses on and the rubber eyecups turned down. Internal reflections are very well controlled  – a little better, in fact, than a high-quality Nikon Action 7×35 I recently put through its paces. Only a few minor ones were seen when I turned the instrument on a bright streetlamp after dark. Optically, the Tento BPC 7×35 delivers a delightfully sharp image in the center, with a decent-sized sweet spot covering about 60% of the field. The instrument delivers a slight yellow tinge which I really like! Indeed, I think it adds quite a bit of vibrancy to the images. One reviewer claimed the image is reminiscent of a fine portrait painting and I tend to agree with that description. Glare is well controlled in the BPC Tento 7×35 too, including veiling glare. Chromatic aberration is also very well controlled in the center of the field, and also at the edges. Off axis, the image shows moderate pincushion (positive) distortion and field curvature. I was also able to check collimation by defocusing a bright star using the right eye diopter. All was well here too. Indeed, I doubt it ever needed recollimation in all its years of service. I was keen to compare this Soviet era glass to my excellent Nikon Action 7×35 (Japanese-made) dating from around about the same time (mid-1980s). Aiming at some moss-laden tree trunks in good March light some 40 yards in the distance I was able to clearly ascertain that the BPC Tento 7×35 had a little bit better contrast which brought out slightly more details in the trunks than the Nikon glass. Greens and browns are especially enhanced in the Russian glass, although the old Nikon offered up a wider (9.3 degrees) and better corrected field of view. On axis, both instruments served up equally sharp images. In yet another test, I compared both instruments in a low light setting, observing the same tree trunks immediately after sunset. While the result was close, I felt the Nikon delivered a slightly brighter image, which surprised me, as this glass has just a fully coated billing while the Tento was understood to be multicoated. It just goes to show that you can’t really judge how bright an image can be based solely on what coatings a binocular has. The Allbinos test of the larger Tento 10×50 sibling revealed a light transmission in the low 70s percent, typical for a quality glass from this era. They also noted that its poor transmission at shorter wavelengths readily explains why it gives a warm yellow tint. Some folk will be put off by this but I find it quite endearing. What’s more, it will never be enough to misidentify a bird  – even the most variegated  – in actual use. Looking at both the Nikon Action and Tento BPC 7×35 (see below), the reader will note their very similar dimensions. As I’ve discussed in my review of the Nikon Action, its great optical performance is the result of using large high-quality prisms as well as having a longer focal length than most other 35 mm Porros on the market. Could the excellent optical performance of the Tento BPC 7×35 be attributed to its longer than average focal length also? Maybe so!

From Russia with Love: A Classic Tento BPC 7×35

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The Nikon Action 7×35 (right) and the Tento 7×35 (left)

The Tento BPC 7×35 serves up a very relaxed viewing experience owing to its 7× magnification. Depth of field is also fantastic in this glass, minimizing the need to re-focus on targets beyond a few tens of meters in the distance. Close focus was measured to be 4.39 m. The fast focus wheel works brilliantly, allowing the user to rapidly refocus when the need arises. This makes it especially useful to birders. As I spent more time with this classic Soviet era glass, I became acutely aware of why it performs so well after all these years. They were built for the harsh Russian environment. Taking advantage of a long and unseasonably chilly March cold snap in 2023, I tested how the focuser would behave in the late evening as the temperatures fell below zero outside. I had already extracted any water vapor inside the glass by storing it in one of my desiccant-filled Tupperware containers – a simple way to keep all of my Porros from fogging up internally. I can report that even after a couple of hours in these conditions the tension of the focus wheel hardly changed at all.

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The Tento BPC 7×35 enjoying the great outdoors

I’ve thoroughly enjoyed test driving this charming glass from behind the Iron Curtain. It works flawlessly and delivers excellent images. Let’s just say it’s the best £25 I’ve ever paid for a binocular! But it has also consolidated my belief that roof prism binoculars are just not good value for money. I would recommend this binocular to anyone looking for a fine, robust glass that has already stood the test of time and will likely last another generation if looked after carefully. To render it fog proof, prepare a watertight Tupperware container filled with 20×10 g sachets of activated silica gel. Make sure to rack out the focuser a little to ensure efficient diffusion of gases. Store your instrument inside this container at room temperature for about 4 days (revised down from 7 days). It will draw out any remaining water vapor inside the chassis, so it can’t fog up inside. And if you continue to store it in this way, it will remain so indefinitely.

A Brief Exploration of a KOMZ 8×30 Classic Porro

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A Brief Exploration of a KOMZ 8×30 Classic Porro

A 1977 Vintage KOMZ 8×30

After the rather joyful experience with the Tento BPC 7×35, which turned out to be a real peach of a binocular, my interest in classic Russian glass was piqued, so I decided to investigate a couple of 8×30 Porro prism binoculars manufactured by another Russian optics house, KOMZ, which stands for Kazan Optical and Mechanical Plant, that specializes in the production of high-quality optical equipment. The company was founded in 1940  in the city of Kazan, located in the Republic of Tatarstan in Russia. Initially, KOMZ produced military-grade optical devices such as binoculars and telescopes for the Soviet Union. Today, the company continues to produce a range of optical equipment including riflescopes, binoculars, telescopes, and spotting scopes for both civilian and military use. KOMZ is known for its high-quality optics, which are made using advanced technology and precise manufacturing processes. The company’s products are also known for their durability and reliability, making them a popular choice among hunters, shooters, and outdoor enthusiasts. In addition to producing its own line of optics, KOMZ also provides components and optics for other companies in the industry. The company has a strong presence in the international market and exports its products to over 30 countries around the world. Overall, KOMZ is a respected and well-established optics firm that has been producing high-quality optical equipment for over 80 years.

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I bought two of the 8×30 KOMZ binoculars, both from Oxfam stores; one model dated to 1977 (USSR) and the other a later 1992 (Russia) which had an 8×30 M designation. Both instruments have an all-metal quality construction, weighing about 600 g. The 1977 instrument came with the groovy orange eyepiece filters, shown below: Why, one may ask, did KOMZ manufacture these filters? Well, it turns out that older Russian binoculars often came with orange eyepiece filters because they were designed for use in  snow-covered terrain where the strong orange filter greatly improves contrast. The orange filters also helped to improve image clarity and contrast by blocking out blue light, which can cause glare and reduce visibility in the same situations. In addition, the orange filters also provided some protection against harmful UV radiation from the sun, especially when exposed to blinding winter snow. This was particularly important for people who used binoculars for extended periods, such as hunters and military personnel. Although both instruments are separated by 15 years according to the serial numbers, their design features look pretty much identical to my eye. The large central focus wheel on the 1977 model worked well but had a significant amount of play. The later 1992 model had a better focuser, with less free play, though I did note that a small amount remained. Testing these in some subzero night time temperature exposures showed that they continued to work well even after exposing them for a couple of hours. Like the Tento BOC 7×35 I tested, these KOMZ focus wheels did not slow up. The eyepieces are made from some hard plastic and are decently comfortable but do not have enough eye relief to accommodate eye glass wearers. The right eye diopter worked well in both instruments, and I was impressed by how rigidly they kept their positions compared with several more recent Chinese and Japanese-made 8×30 Porro prism models I have personally tested. Both models had accumulated quite a bit of dust and grime on the outside of the chassis, but after cleaning them carefully, I was able to see that the insides had not accumulated much in the way of haze, and both were fungus free. Both instruments appear to have decent quality BaK4 Porro prisms. Examining the exit pupils of these instruments revealed consistent results. The antireflection coatings applied to the 1997 and 1992 models looked different in daylight though. The 1977 model had a pronounced purple bloom on both the objective and ocular lenses, but those on the 1992 unit were far more subdued. Testing both instruments in bright overcast conditions showed that the optics were pretty much identical in both instruments, which genuinely surprised me as I had expected the 1992 model with the ‘M’ billing to be brighter. That’s because I understood the 1992 model to have a full multicoating. Both served up sharp images within a nice big sweetspot very reminiscent of a mid-1980s Zeiss Jenoptem 8×30 I showcased a while back. Conducting some tests after dark showed very similar results when I turned them on a bright sodium streetlamp. There was some glare and a few significant internal reflections in both instruments. The same was true when I used them in the open air, where both units exhibited quite high levels of glare; too much, in fact, for my liking. Overall, I was a little underwhelmed by these sexy

A Classic Asahi Pentax 8×40

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looking compact 8×30 Russian glasses. They are nice collector’s items, but not something I would like to use on a regular basis.

A Classic Asahi Pentax 8×40 I’ll be honest: when I first viewed through this binocular I asked myself, “What on earth is this for?” These Pentax Asahi binoculars were manufactured in Japan from the 1950s through to the early 1970s. I bought mine off an amateur astronomer from eBay for the princely sum of £40. The build quality is exemplary: all metal housing, lovely leatherette armoring and large oversized prisms. The focus wheel is silky smooth to operate and moves through about four fifths of a revolution clockwise from closest focus (measured at 5.2 yards) to infinity. Even though the instrument must have been close to half a century old, it was in tip top condition, so it must have been stored capped, and in a dry place at room temperature to avoid internal fungal growth.

A 1970s vintage Asahi Pentax 8×40 Wide Field

The objectives have good antireflection coatings  – probably single coated Magnesium fluoride – and they still looked immaculate after all these years. The eyecups are fashioned from a very hard plastic and eye relief is very short – par for the course in these old Porro prism binoculars. The right eye diopter ring is

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beautifully delineated and stays in place firmly – unlike many other diopter rings I’ve sampled from this era.

The basic antireflection coatings on the Asahi Pentax 8×40 still look immaculate after all these years

Things get a bit weirder when the ocular lenses are examined. They have a very bright gold colored hue. Things get a whole lot stranger when you look though the instrument. The color cast is a bluish green! That said, the field of view is a very impressive 9.5 angular degrees, larger than my Nikon Action 7×35 and also my Nikon E II 8×30. And the image is very sharp with a huge, big sweetspot. Indeed, it would make the Swarovski NL Pure 8×42 blush with its smaller 9.1 degrees!

Check out the gold coatings on the ocular lenses

A Classic Asahi Pentax 8×40

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Doing some research on this model revealed some very interesting information. First of all, the coatings are not actually gold but simply reflect gold light from the image – a consequence of the thickness of the coatings used. Because longer visual wavelengths are effectively removed from the image, it readily explains the blue-­ green cast to the images. Apparently, these coatings were applied to the ocular lens in order to mimic the effects of sunglasses, to cut down on glare in bright sunny conditions. Furthermore, some inveterate tinkerers disassembled the ocular lens assembly to find the gold layer and using isopropyl alcohol or some such applied considerable elbow grease to remove the coating, which created a much more neutral color cast. Was it worth the effort? To some, the answer appears to have been yes. But other accounts I’ve read claimed that this made the images significantly worse, with reduced contrast and even dimmer images. It turns out Pentax optical engineers added these coatings at some stage during the production run of these instruments, as some models don’t have them while others do. What’s more, the intensity of these coatings apparently varied over time too. Spending some time with the instrument, I continue to be quite impressed with its enormous and well corrected field. This was confirmed by viewing the Moon and bright stars at night, where the images remained sharp pretty much all the way across the field. And this was achieved without the use of modern field flattening lenses. I did detect some significant internal reflections when I turned the instrument on a bright gibbous Moon or sodium streetlamp. The eye quickly becomes adjusted to the colour shift in the Pentax Asahi 8×40, yet despite its very sharp, high contrast images in a very well corrected 9.5-degree field of view, I cannot recommend it as a birding glass, simply because the color information so essential for confirming an avian species would be mostly lost or distorted beyond recognition. But otherwise, it’s quite a fun glass to use. One other drawback deserves mention. It tips the scales at 979 g without the strap; so this is one heavy instrument. The good news is that it can be mated to a tripod for steadier viewing.

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The Pentax Asahi 8×40 can be mated to a tripod for steadier viewing

The Tip of a Proverbial Iceberg The whole experience with the Pentax Asahi 8×40 got me thinking about just how wide these old classic binoculars could go. And it turns out that 9.5 degrees was quite pedestrian compared with some of the ultra-wide field instruments I began to hear about. Paul Wehr, who kindly cataloged the evolution of the venerable Swift 8.5×44 mm Audubons discussed earlier in the chapter, informed me of some amazing instruments once available to the binocular enthusiast. Take the Swift Holiday 7×35 MKII with its 11-degree field of view. Though it lacks a full multicoating, the images are tack sharp within an enormous sweetspot. Paul informed me that in good lighting conditions, the views are spectacular through this old 7×35, but fall off a bit compared to the best modern instruments in dull overcast conditions.

The Tip of a Proverbial Iceberg

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This old Swift Holiday 7×35 MKII has an enormous 11 degree field. (Image Credit: Paul Wehr)

The era – from the 1960s to the1980s – in which these ultra-wide angle binocular models were made should really be considered to be a golden age for wide angle binoculars. Many established optical firms were in on the race to create stunning wide-angle views. Another example Paul brought to my attention was the Bushnell Tamron 7×35. Fashioned in Japan, its small, lightweight and also delivers an 11-degree field of view. Wider still, Paul showed me his 7×35 Sans & Streiffe with a 13-degree field of view! I was also informed on an online forum that the Russians once built an 8×30 model with a 13-degree field! These would surely cause pronounced tunnel vision in even the widest-angle modern binoculars available today!

The Sans & Streiffe 7×35 with a whopping 13 degree field of view. (Image Credit: Paul Wehr)

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Grandfather of the Widefields: The Zeiss Delactis 8×40 Digging more deeply, we can trace the origin of wide-angle binoculars back a whole century or more. For example, consider the Delactis 8×40 was one of Zeiss’ first commercially produced wide-field binoculars. It was manufactured between 1921 and 1936 with a rarer center focus version, the Delactem, being brought to market from 1931 to 1938 for civilian use and from 1943 onwards for military use only. It was probably discontinued because of the great popularity of the Deltrintis and Deltrintem 8×30 models which delivered similar but not quite as good optical performance but were more compact with  lighter weight. Optically, most users still consider this to be a wonderful binocular, with much better than expected since the lenses are entirely uncoated. With a 5  mm exit pupil and 70 degree AFOV it’s extremely comfortable to look through with an exceptionally sharp central image, going a little soft at the field edges but in a way that is very gradual and largely unobtrusive. With modern anti-reflective coatings this Zeiss Delactis would be an outstanding instrument. The build quality is superb, with prisms which seem to fit so perfectly and tightly in their bases. Today the Delactis 8 × 40 is about as good as you’ll get for a pre-World War II binocular in terms of overall innovation and quality (all the original sealings looked intact), and although it has obviously seen some use, it was still in perfect collimation. You can still pick these up for a few hundred dollars on eBay.

The Zeiss Delactis 8×40. (Image Credit: Holger Merlitz)

Of course, enormous fields were not just the preserve of Porro prism binoculars. For example, Leitz produced a cute little 6×24 pocket binocular called the Amplivid produced between 1956 and 1962 sporting a whopping 12.1-degree field of view. Weighing just 360 g, and roughly 11 cm square, this would have made an awesome pocket binocular back in the day. The prisms were coated with aluminum and were

Back to the Future

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not phase corrected reducing the light transmission to about 60%. The outer field was poorly corrected though, showing strong field curvature, coma and astigmatism. Eye relief was very tight too at 11 mm. That being said, can you imagine what a modern version of this pocket glass would perform. The mind boggles! The little Amplivid regularly shows up on eBay for prices of about $400–$600.

The Leitz Amplivid 6×24. (Image Credit: Holger Merlitz)

Back to the Future These revelations collectively raise significant questions in my mind about the future of binocular designs. If these classic binoculars were capable of serving up such enormous fields, why are designers not looking at these afresh today? I believe that as the demand for wider and wider fields becomes the driving factor in future binocular design, these older models must be re-examined with a view to designing modern glasses sporting these enormous fields. The inclusion of field flattening optics in the eyepieces of such instruments would help keep the image crisp right the way to the field edges. It would be a market game changer for sure! I’d also recommend these classic glasses to readers of this book. If you hunt online auctions like eBay and others, you’re quite likely to get very high quality classic Japanese, Russian and German glass for a relatively small financial outlay. And even if they’re not in tip top condition they can likely be restored to a full bill of health for a small additional restoration fee.

Chapter 31

Earth and Sky

Moonburst: Local Midnight, April 8 2020

We live in very uncertain times, with wars in Ukraine and the Middle East, famines and pestilence never far from our thoughts. The COVID pandemic has wreaked havoc with countless millions of people across the world, economies decimated, and whole ways of life destroyed. Watching the news brings nothing but misery, as © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_31

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we see whole nations struggling to make ends meet amid an energy crisis of gargantuan proportions. It’s all too easy to feel helpless and overwhelmed by all the events in the human world but for me, binoculars have given me a new lease of life, a vehicle to rise above the drudgery of the workaday world, to seek out beautiful, wild and quiet places unscathed by human calamity. Our planet is ripe for exploration. Protected by a just-right atmosphere of mainly nitrogen and oxygen, the earth is chock full of living things and amazing geological features that bring joy to the human heart. Our atmosphere is neither too dense nor too rarefied, allowing us to peer deeply into the Cosmos, where we can catch a glimpse of eternity. If the atmosphere were only slightly thinner, we’d freeze to death. But if it were too dense, it would extinguish the light from the stars altogether. The human eye can only see so much, but with optical instruments we can improve our lot, to see things in new and unexpected ways. That’s how I see my binoculars; simple tools that bring heaven and earth closer, providing a perspective that transcends the limitations of my corporeal form. I am especially fortunate to live in a beautiful part of the world, away from the cities. Out here in the sticks, I can enjoy the beauty of the natural world more fully, in quietness, surrounded as I am by hills and valleys, green fields and lovely streams of cool, fresh rainwater that sustain the lives of all living things. My binoculars are the perfect tools for combining the beauty of the night sky with that of the comeliness of terra firma. In this final chapter, I’d like to share with you some of the kinds of activities I get up to in order to bring these worlds together. My wide-angle binocular provides a power of just 8 diameters but has an angular field of view wide enough to fit 17 full Moons in the same wonderful portal. And with their decent light grasp, especially in fading or low light, they’re powerful enough to allow me to simultaneously appreciate sights in the heavens and on earth. Surrounded by mature trees, sometimes many times older than myself, I have grown terribly fond of framing familiar celestial sights, such as the Pleiades and the Hyades in the foreground of their impressive branches. Sometimes, I would wait for the stars in these clusters to fall in altitude after they culminate in the south, when they’re seen to ‘hover’ over the conifer trees beyond my back garden. And if, by chance, the presence of a gentle breeze in the binocular image is witnessed (and it can happen a lot!), then you’ve got a home run; an epiphany of sorts! At other times, I will plan a vigil where the soft light from the stars fills the background whilst the foreground is occupied with denuded winter branches of the deciduous trees near my home. A little light pollution can be advantageous in such circumstances, as it can help illuminate the tree branches making them stand out more boldly against the stellar backdrop.

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Even in low light, binoculars bring out details quite beyond the reach of the naked eye: Sunset, Culcreuch Pond, March 1 2021

Living inside a long valley with verdant hills that soar to about 1000  feet on either side, my binocular is good at framing the rising Moon as its silvery light clears their summit in the east, or as it sinks behind the hills in the west. There are many times where I can plan to observe the Moon and the hilltops in the same field, creating visual scenes that leave a deep impression on me. How fortunate we are to witness such scenes, safe and secure at the bottom of a great sea of fresh, clean air. Ever since childhood, I have been attracted to storms, often venturing out to feel the energy they generate in the atmosphere. Sometimes these storms occur on moonlit nights, and I would think it nothing to grab my binocular and carry myself off to some favorite haunts, woody glades and the like, where moonbeams create wonderful atmospheric scenes, complemented by the sound of wind whistling through their branches. My binocular has renewed my interest in observing the full Moon, not in and of itself, but when it is surrounded by low lying and fast-moving rain clouds, as often happens here in the British Isles. I watch as these clouds enter the outer field, inching their way toward our bright satellite, and all the while lighting up with beautiful colors caused by refraction of moonlight through raindrops. The colors often start off deep and moody, like dried-in blood, when far from the Moon, but as they move ever closer, the colors they generate; gorgeous shades of pink, yellows and even rose tints; saturate the cones on my retina, upwelling feelings of great happiness.

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A gorgeous place to watch the Moon’s silvery reflections upon the water. Culcreuch Pond, November 24 2021

The structure of clouds backlit by moonlight reveals wonderful, highly complex structures– knots, filaments and pleated sheets. Often the scene reminds me of the play of light on the matter which is expelled into the shells of planetary nebulae as imaged by a great telescope, with a white dwarf star being replaced by our very own Moon at its epicenter. Such natural shows of light and form rank as some of the loveliest and most surreal binocular images one is likely to capture. Sometimes, great gaping holes in the heavens open up around the clouds, allowing the light of the distant stars to be seen near the full Moon. Another worthwhile project is to image the bright Moon over a large expanse of water, especially during calm conditions, when its reflection is quite mirrorlike. Under the light of a town or city, smaller binoculars do just fine, like my little Zeiss Terra pocket instrument. You can even wander through your neighborhood finding interesting foreground subjects to frame your celestial scenes in advance of an event.

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Check out the details on those rocks: Ramsey Island, Pembrokeshire, Wales, August 8 2022

Venturing out on the water with binoculars in hand on a bright summer day is a great way to explore the coastline. The British Isles have undoubtedly some of the prettiest coastlines in the world, shaped by millions of years of geological activity and erosion. My little 8×30 Porro prism binocular, with its enhanced 3D views, is ideal for studying the relief in the rock structures and the various layers laid down over the ages.. But choosing the right light is crucial to seeing the finest details. For example, while taking a boat on the Irish Sea off the coast of Pembrokeshire, south Wales, it’s best to wait until the late afternoon when the Sun falls into the western sky illumining the coastline in beautiful golden sunlight.

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Magical Noctilucent Clouds at local midnight. June 2023

At my high northerly latitude, summer brings amazing noctilucent clouds during June and July. Noctilucent, or ‘night shining’ clouds, are tenuous cloud-like phenomena in the upper atmosphere of earth, detectable as a diffuse scattering layer of water ice crystals near the summer polar mesopause. They are most often observed during the summer months from latitudes between ±50° and ±70°. Too faint to be seen in daylight, they are visible only when the observer and the lower layers of the atmosphere are in our planet’s shadow, but while these very high clouds are still in sunlight. Recent studies suggest that increased atmospheric methane emissions produce additional water vapor once the methane molecules reach the mesosphere – creating or reinforcing existing noctilucent clouds. I enjoy sitting out on a comfortable reclining chair with my 10×35 binocular, studying their delicate forms: herringbone arrangements like sand ripples on a beach at low tide, whirls and delicate gossamer strands lit up from a Sun just a little bit below my northeastern horizon. Noctilucents are the highest clouds in earth’s atmosphere, located in the mesosphere at altitudes of around 76–85 km (249,000–279,000 ft). Truly magical! Dawn and dusk are good times to see some spectacular sights, such as the bright planet Venus sinking low into the sky, often silhouetted by interesting terrestrial structures, such as a distant hill, an old barn house or silo, church or windmill. By getting to know your horizons, sublime scenes can be captured with your binocular, bringing heaven and earth together.

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Cityscapes can also be used to enhance the binocular view. Framing bright star clusters like the Pleiades or a crescent Moon in the background to an old church spire, domed cathedral, or grand municipal building, can make for a very fetching sight. Photographers imagine likewise, of course, but the impromptu binocular experience is an even greater liberal art! One of my favorite activities on Spring evenings is to take a saunter with a good quality glass and observe the beautiful gloaming light as it falls on freshly sprouted leaves shortly before sunset. The forest walks are adorned with bright yellow Daffodils that delight the eye with a blaze of color. This early in the season, the leaves on the deciduous trees emerge with an intense lime green hue which can mesmerize the eyes. Soon they’ll be wide open and harvesting sunlight for the trees. But I also love looking at the amazing details coming through on tree trunks, the moss and lichens glimmering after a brief shower of rain and the contours in the bark coming through in astonishing detail.

The Gloaming: May 2023

Spring is also the time when Swallows come back from their long sojourns from North Africa, where they spend the winters. Most times, I’ll hear their characteristic high-pitch screeches away off in the distance before ever seeing them. Over the weeks, their numbers grow stronger until you can see them in pretty much every direction you turn your glass. I cherish the amazing, high-speed aerial displays these birds perform almost effortlessly as they swoop down from on high to gorge

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on early hatching flying insects. For such activities, it’s a case of horses for courses with me. For these observations I always reach for either my Nikon E II 8×30 or Nikon Action 7×35 for their large and superbly corrected fields of view – 8.9 and 9.3 degrees, respectively – to help me follow them as hey flit from field to field over water ponds and rivers of the Endrick Valley.

A bicycle ride and a binocular bring magical views of the Endrick valley> June 2023

The summer brings many new visitors to the British Isles, including busy Pied and Grey wagtails. The Pied variety mainly inhabits the fields near my home, while the Grey Wagtails hang out beside the river feeding on insects. Sand Martins make their nests on the muddy riverbanks. To see them at their best, I select a spot on the opposite bank of the river where they’re nesting, and lying low, I bring the binocular to my eyes and drink up the views. This stretch of river runs through an old football field with trees on either side. This is where I go and watch Buzzards. They nest in the taller trees, and I often see them setting to flight when they see me walking along the well-treaded path through the field. On a warm summer’s day, I would lie on my back and glass them as they glide on the summer thermals. More curious individuals will often come closer to investigate and that’s when I get the best views when they can get within 20 meters above my head.

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As summer gives way to autumn, the Scottish landscape turns from a verdant green to riot of tans, reds and browns as the leaves shut down their chlorophyll production exposing the accessory pigments – xanthophyl, phycocyanin and phycoerythrin – creating a riot of autumnal color. On bright days, when weak fall sunshine drenches the dying leaves, the binocular views are truly magical. The Swallows that provided such entertainment during the summer gather to perch on telephone lines in large groups before beginning their long journey back down to southern Europe and North Africa. The hills begin to change color as the heather matures and paints the uplands in gorgeous shades of purple which I enjoy scanning with a wide-angle glass. Autumn migrants, such as handsome Redwings and Fieldfares grace the countryside, creating fantastic new birding opportunities. With the arrival of autumn, the skies get truly dark once again and the nights lengthen, encouraging me to turn my binoculars skywards once again in search of celestial booty. The Pleaides and Hyades are the first of the autumn star clusters to appear over the eastern horizon. The Milky Way through Cygnus, Lyra, Perseus and Cassiopeia are ripe for exploration, inviting me to pull out my zero-gravity chair and lay on my back with my binoculars to survey its cavernous reaches. The Perseid Meteor Shower on August 12 is always a joyful experience where I break out my little 2×40 super-wide angle Galilean binocular to count shooting stars as they blaze from their radiant in Perseus. As the days get shorter, mighty Orion appears on the eastern horizon heralding the onset of winter. The days get frightfully short during the last months of the year, and I’m drawn to the outdoors earlier and earlier to catch the best light. But even though there are some bright days with brilliant winter sunshine, most afternoons are dull, necessitating the use of larger binoculars that can collect more light. It’s during these days that I get most use out of my 8 × 42 mm binoculars to watch wildlife at my various local patches. On the coldest, gloomiest winter days, I stay at home and engage with the bird feeders in my back garden which attract all manner of birds; Bluetits, Great Tits, Long Tailed Tits – veritable flying spoons – Robins, Dunnocks, neurotic Nuthatches and even the odd Wren. I leave my little pocket glasses on the kitchen window ledge, watching to see which birds turn up next. Surprises are always to be expected!

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Binoculars are indispensable tools for glassing birdfeeders

The woods near my home are great places to observe colorful Jays during the winter. I often see them quietly searching for acorns under the leaf litter but on other days I catch them flitting between the trees, communicating with each other in loud, rasping screeches. Roe deer roam the forests too and I’m always delighted to catch a glimpse of Red Squirrels scampering among the trees. A burn runs through the woods carving out a rather deep channel with steep banks on either side. It is these water holes that are well worth glassing for small birds such as little Wrens which often make their nests nearby.

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Glassing on a snowy day can be thrilling. River Endrick, February 11 2021

When the first snows fall, the landscape is transformed into a veritable winter wonderland and the surrounding hills gleam when weak winter sunshine illumines the higher peaks, creating wonderful glassing opportunities. After dark, the great winter constellations, Orion and Gemini, grace the meridian providing ample opportunities to explore their splendid stellar associations and nebulae. Sometimes I’d rise in the wee small hours of the morning and glass coruscating Sirius hanging just above the tree lines to the south, connecting earth and sky at the close of the year. These are just a few of the activities I enjoy throughout the year, exploring the wild places near my home. But you too can find your wild or quiet places to contemplate the wonder of the natural world. And your binoculars will only serve to enhance those experiences. So happy glassing!

Correction to: Binoculars 101

Correction to: Chapter 1 in: N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-­3-­031-­44710-­5_1 The original version of the chapter “Binoculars 101” was inadvertently published with incorrect equations. The chapter has been updated with correct equations.

The updated version of this chapter can be found at https://doi.org/10.1007/978-­3-­031-­44710-­5_1 C1 © Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5_32

Binocular Repairs and Restorers

Netherlands De Kijkerspecialist Malerstraat 5 1531 NW Wormer Nederland [email protected] UK 16, Wheatfield Road, Selsey West Sussex, PO20 0NY, United Kingdom Telephone: 01243 601 365 [email protected] East Coast Binocular Repairs Stable Yard, Ryston Hall Ryston Norfolk PE38 0AA info@http://binocular-­repair.co.uk/ Viking Optical Ltd, Blyth Road, Halesworth, Suffolk IP19 8EN [email protected] USA Suddarth Optical Repair 1408 Briarwood Ln. Henryetta, OK. 74437 [email protected]

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5

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Binocular Repairs and Restorers

Canada La Maison de l’Astronomie P.L. 8074 St-Hubert Street, Montreal Quebec, Canada H2R 2P3 https://maisonastronomie.ca/en/product/e-­binocular-­repairs/ Sweden Kameraservice Köpingsvägen 12 732 31 ARBOGA [email protected] Switzerland Optik Riesen Toffenhohle 4 3125 Toffen [email protected] Australia Optical Repairs PO Box 3344 Darra QLD 4076 Australia. [email protected]

Glossary

Aberration  An optical defect that degrades an image Achromatic  A combination of crown and flint glass which greatly improves color fringing Angle of Incidence  The angle between the ray of light and the normal as it enters the glass Angle of refraction  The angle between the refracted ray and the normal as it travels through the glass Apparent Field of View (AFOV)  The angular size of the entire image True Field of View (TFOV)  The angular size of the object. It can be calculated by dividing the AFOV by the magnification Diopter  Usually located under the right eyepiece or built into the focus wheel which allows one to adjust the focus in one eye independently of the other Depth of Field (DOF)  The range of distances from the objective where the image appears sharply focused. DOF drops off with the square of magnification Stereopsis  The ability to perceive the world in 3 dimensions. Stereopsis is better in Porro prism binoculars because the objectives are further apart than eyepieces. It is more pronounced at higher magnifications Extra Low Dispersion (ED) Glass  glass composed of exotic materials like fluorite which helps reduce chromatic aberration (color fringing) Exit Pupil  The round shaft of light emerging from the eye lenses Inter Pupillary Distance (IPD)  The distance between the exit pupils Eye Relief  The distance from the eye lens to the exit pupil Refractive Index  A measure of the relationship between the incident and refracted rays as it passes through a lens. The greater the refractive index, the more light bends as it passes through a transparent material Vignetting  the drop off in the illumination of the image at the edge of the binocular field Phase Coating  A coating applied to roof prisms that corrects the differential phase shift in the beams of light passing through the optical system

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Glossary

Critical angle  the angle of incidence above which total internal reflection occurs Porro Prism  A right-angled isosceles prism that uses total internal reflection to bend light passing through a binocular Schmidt Pechan  a type of roof prism found in many commercial roof prism binoculars BaK4  A type of Barium crown glass commonly found in binocular prisms BK7  A type of Borosilicate glass which is lighter and less dense than BaK4 glass Off-axis  relating to a part of an image away from the center Lateral Color  A type of chromatic aberration that is seen towards the edges of an image Magnification  A measure of how much an image is enlarged relative to the naked eye Anti-reflection coatings  These are the coatings applied to an optical system that increase light transmission and image contrast Resolution  The degree to which two objects can be distinguished from each other. In general resolution scales with the aperture of the objective lenses and magnification. Spherical aberration of the exit pupil  a spherical or oblate shadow (blackouts) that appears to move around the image resulting from misplacement of the eye with respect to the eyepiece lenses. Total internal reflection  A type of reflection within a prism which occurs when the angle of incidence exceeds the so-called critical angle. Spherical aberration  a phenomenon in which the outer parts of a lens do not bring light rays into the same focus as the central part Coma  An aberration in the lens or other components that results in off-axis point sources such as stars appearing distorted, appearing to have a tail (coma) like a comet Astigmatism  An optical aberration where rays that propagate in two perpendicular planes have different foci. Field Curvature  An aberration which occurs when the sharpest image is formed not on a flat plane but on a curved surface. Chromatic aberration  this results when the lens system fails to bring all colors of light to the same focus point resulting in blue-purple fringing around highcontrast objects which reduces contrast

Index

A Adapter, 220, 281, 288, 293, 390, 394 Albireo, 163, 257, 285, 292 Alpha Persei Association, 65, 113, 134, 162, 170, 221, 229, 272, 276 Altair, 162, 170, 271, 273 Andromeda Galaxy, 52, 162, 221, 253, 259, 294 Aperture, 4, 7, 10–11, 23, 25, 31, 44, 52, 59, 65, 74, 81, 83, 85, 86, 92, 103, 128, 134, 149, 151, 155, 164, 188, 217, 218, 227, 229, 242, 248–250, 256, 257, 260, 264, 267, 270, 271, 278, 286–289, 291, 293–295, 297, 300, 307–309, 321, 324, 342–344, 353, 354, 361, 365, 369, 373, 376, 377, 381, 382, 388, 392, 418, 419, 422, 423, 429 APM, 117, 273–274, 296–297 Argon purging, 361 Astigmatism, 105, 155, 182, 229, 255, 262, 288, 295, 398, 424–426, 501 Athlon Cronus, 184, 185 B Baader Astrosolar material, 288 Barr & Stroud Savannah, 153–156 Series 5, 41–45, 70, 109, 189–192, 267 Series 8, 167–170, 437 Betelgeuse, 52 Blackouts, 8, 9, 39, 44, 50, 66, 72, 86, 106, 110, 113, 116, 120, 134, 135, 140, 147, 161, 166, 172, 183, 204, 210, 228, 270, 304, 322, 356, 417, 472

© Crown 2024 N. T. English, Choosing & Using Binoculars, https://doi.org/10.1007/978-3-031-44710-5

Bresser, 268–269, 323 Bushnell, 106–107, 235, 305, 401–403, 499 C Canon, 19, 37, 84, 184, 185, 301, 302, 304–311, 319, 320, 438, 447 Celestron Nature DX, 152, 153 Outland, 33, 34 Regal ED, 179–184 Trailseeker, 56, 59–60, 96–99, 119, 127, 192, 258, 259 Chromatic aberration (CA), 11–13, 40, 44, 53, 56, 64, 66, 80, 93, 95, 99, 104, 105, 111, 112, 120, 133, 139, 141, 153, 157, 161, 162, 169, 174, 177, 182, 187, 189, 192, 193, 196, 198, 199, 203, 205, 210, 213, 215, 221, 229, 239, 257, 261, 264, 272, 275, 276, 283, 285, 288, 290, 294, 295, 305, 306, 310, 324, 332, 336, 350, 356, 357, 362, 365, 370, 381, 382, 386, 392, 399, 422–423, 480, 483–485, 487, 490 Clouds, 36, 52, 128, 161, 177, 191, 247, 252, 254, 262, 275, 407, 505, 506, 508 Coma, 90, 113, 159, 182, 229, 264, 288, 424–426, 479, 501 Craters, 116, 170, 221, 247, 257, 268, 272, 275, 285, 288, 292, 306, 452 D Deneb, 128, 162, 221 Depth of focus, 17, 111, 113, 117, 187, 267, 275, 283

519

520 Diopter, 16, 32, 35, 39, 42, 44, 45, 47–49, 55, 62, 66, 69, 71, 74, 75, 77–79, 85, 92, 95, 97, 98, 101, 103, 107–109, 111, 112, 115, 125, 131, 133, 138, 139, 142, 145, 153, 154, 156, 161, 163, 168, 171, 173, 176, 181, 182, 186–188, 190, 193, 194, 196–198, 201, 205, 209, 210, 213, 214, 218, 223, 227, 232, 236, 242–245, 251, 261, 262, 266, 269, 271, 280, 282, 287, 293, 295, 301, 303, 308, 309, 332, 334–336, 341, 343, 344, 347–350, 354, 356, 362, 365, 369, 370, 373, 382, 383, 388, 402, 418, 421, 433, 436, 465, 468, 478, 489, 490, 494–496 Double Clusters, 52, 65, 113, 128, 162, 163, 172, 221, 229, 254, 268, 272, 283, 286, 288, 440, 472 E ED glass, 12–15, 44, 50, 71, 88, 93, 99, 106, 121, 123, 126, 127, 136, 141, 169, 175, 184, 185, 188, 189, 193, 207, 208, 223, 225, 228, 230, 231, 259, 263, 264, 274–279, 297, 310, 332, 336, 341, 342, 346, 356, 360, 361, 364, 365, 370, 376, 381, 382, 388, 394, 399, 402, 422, 433, 434 Eschenbach, 46–48 Exit pupil, 7–8, 10, 11, 20, 31, 36, 43, 44, 47, 57–59, 64, 67, 68, 71, 72, 76, 77, 80, 83, 86, 87, 95, 99, 104, 109, 113, 119, 120, 126, 133, 134, 140, 145, 149, 151, 155, 160, 165, 168, 172, 178, 181, 182, 184, 187, 191, 203, 209, 217–219, 222, 228, 237, 250, 254, 255, 257, 259, 282, 288, 295, 297, 300, 301, 303, 308, 321–324, 334, 342, 353, 383, 410, 418–420, 426, 432, 435, 469, 472, 480, 486, 490, 494, 500 F Field curvature, 17, 36, 40, 44, 47, 48, 51, 76, 79, 87, 88, 90, 92, 99, 105, 111, 116, 117, 119, 145, 151, 155, 159, 165, 169, 170, 172, 176, 179, 182, 192, 202, 219, 221, 229, 232, 252, 255, 258, 262, 267, 271, 272, 287, 288, 309–310, 353, 362, 377, 382, 424–425, 469, 472, 479, 490, 501 Field of view, 4, 9, 15, 17–18, 27, 28, 33, 36, 40, 43, 45, 50–53, 56, 58–60, 64–67, 71, 72, 76, 79, 81, 85, 87–90, 92–95, 99–101, 104–106, 108–113, 117,

Index 119–121, 123, 124, 127, 131, 133–137, 139, 140, 142, 143, 145, 151, 153–156, 162, 163, 169, 170, 178, 183, 187, 189, 191–194, 196, 199, 203, 206–208, 210, 212, 213, 215, 220–223, 226–238, 242–245, 249, 250, 258, 261, 264, 266–268, 270, 271, 273, 274, 276, 278, 282–286, 288, 290–292, 297, 299, 301, 304–306, 308–310, 320–325, 331, 333, 336, 342–345, 347, 348, 350, 353, 356, 362, 368–370, 372, 376, 377, 380–382, 387, 388, 392–394, 402, 418, 422, 426–428, 433–436, 438, 452, 459, 465, 472, 473, 479–486, 490, 496–500, 504 Focus wheel, 16, 22, 32, 35, 37, 43, 47, 48, 50, 55, 58, 67, 69, 70, 74, 75, 78, 81, 85, 86, 89, 96, 98, 103, 107, 108, 113, 115, 119, 123–125, 127, 131, 133–135, 138, 139, 141, 142, 145, 151, 154, 157, 158, 160, 162, 167, 168, 171–173, 176, 181, 186–190, 193, 194, 196, 198, 201, 205, 209, 210, 213, 214, 221, 222, 227, 232, 255, 256, 261–263, 266, 268, 270, 287, 303, 305, 308–310, 321, 332, 335, 336, 341, 343, 346–350, 354, 356, 369, 370, 382, 383, 386–388, 391, 394, 417, 418, 424, 433, 435, 438, 465, 466, 468, 469, 473, 477, 478, 486, 487, 489, 491, 494, 495 Fresnel equations, 14 Fujinon, 224–225, 273, 279, 289–291, 297–298, 310–311, 321–322, 397–399 G Galilean binoculars, 249, 250, 439, 511 Galileo, 27, 28, 292 German Precision Optics (GPO) Passion ED, 92, 93, 107–111, 113, 155, 164–166, 199–204, 210, 211, 227, 232, 363–365 Passion HD, 109, 110 H Harness, 122, 181, 197, 250, 343, 415, 449 Hawke, 164–166, 170–174, 225–226, 309–310 Helios Starfield, 249, 253, 254, 439 I Image stabilized binoculars, 299–301, 309, 311, 319–325, 399, 438, 452

Index

521

K Kite, 230, 472 Kowa BD II, 188, 189, 382 Genesis Prominar, 75–76, 381 SV, 35, 37, 43, 118, 382 SV II, 36–37, 118–120, 380, 382, 434, 435

Meopta, 195, 240–241, 363, 371–373 Monocular, 124, 127, 170, 234, 260, 387, 410, 429 Monopod, 35, 39, 106, 183, 186, 229, 258, 259, 264, 267–269, 272, 276, 277, 281, 282, 288, 348, 382, 383, 411–415, 437, 440, 449, 452, 459

L Leica Amplivid, 500, 501 BCA, 44, 47, 53–58, 60–65, 67, 68, 70–72, 125, 334–336 Noctivid, 66, 127, 214–215, 329–333 Trinovid HD, 109, 118, 124–131, 134, 161, 163, 210, 211, 331–333, 342 Ultravid, 42, 44, 47, 67–75, 124–127, 130–131, 134, 140, 192, 278, 308, 310, 319, 331–334, 336 Leupold, 84, 198–199, 369, 393–395 Light transmission, 5, 7, 13, 20, 29, 30, 35, 45, 56, 60, 71, 75, 78, 80, 83–85, 89, 95, 101, 111, 116, 117, 126, 130, 131, 134, 136, 139–143, 146, 150, 159, 166, 183, 187–189, 193, 194, 199, 203, 218, 220, 221, 223–225, 230–232, 244, 245, 248, 255, 266, 267, 269, 270, 273, 277, 278, 280, 295, 297, 301, 302, 304, 309, 330–332, 335, 341–344, 346, 348, 349, 357, 361, 362, 365, 369, 372, 376, 380, 387, 388, 394, 398, 399, 402, 465, 469, 479, 487, 490, 501 Action, 159 EDG, 101, 352, 356, 357 Monarch HG, 91, 132–135, 145–147, 183, 192, 201, 202, 209, 211, 356, 468 Monarch M7, 101, 356

N Neck straps, 34, 46, 55, 62, 77, 81, 101–103, 107, 114, 122, 124, 145, 160, 169, 174, 175, 177, 181, 186, 187, 191, 199, 202, 208, 209, 213, 227, 236, 243–246, 251, 256, 260, 277, 309, 334, 365, 406–407, 415, 435, 471, 478 Nikon Action Extreme, 84, 89, 149–151, 158, 159, 353, 354, 478, 479 Aculon, 84, 89, 90, 150, 151, 158–159, 219, 220, 256, 257, 352–354, 478, 479 E II, ix, 21, 104–106, 115–117, 144, 145, 147, 150, 255, 343, 355–357, 391, 410, 468, 469, 471, 472, 476, 478–480, 496, 510 Travelite, 355 WX, 355, 358 Nitrogen purging, 30, 45, 257, 258, 337, 390 Noctilucent clouds, 252, 508–509

M M13, 116, 163, 221, 229, 264 Magnification, 4, 7, 9–12, 16–18, 21, 22, 24, 27, 30, 31, 33, 34, 61, 64, 65, 67, 80, 81, 94, 117, 122, 134, 167, 187, 189, 212, 217, 218, 220, 222, 236, 242, 247–250, 252, 258, 259, 264, 265, 271, 272, 278–280, 282, 284–286, 288, 291–293, 296, 297, 299, 300, 302, 303, 320, 321, 323, 330, 334, 343, 347, 348, 353, 355, 368, 373, 375, 376, 382, 387, 390, 392, 394, 398, 402, 410, 419, 421, 422, 425, 429, 439, 472, 476, 480, 483, 485, 491 Maven, 185, 206–207, 230, 276–278, 375–377

O Oberwerk 20×65 ED Deluxe, 102, 295 LW, 88, 391 SE, 102–106, 108, 263, 264, 389–392, 433, 434, 436 2000 series monopod, 411–412 Sports ED, 205–207, 390 TR3 tripod, 415 XL series, 296 Opticron Adventurer T WP, 85–88, 92, 220, 221, 269, 369 Aurora BGA VHD, 208–210, 367–370 Discovery WA ED, 368 Imagic IS, 322–323 Imagic TGA WP, 23, 229, 269–273, 436–437 Savanna WP, 90–94, 369 Traveler BGA ED, 370 Orion belt stars, 257, 283, 284 Orion Nebula, 229, 288, 294, 482

522 P Parallelogram mount, 320, 414, 415 Pentax AD, 41, 388 Asahi, 385, 495–498 Papilio II, 22, 76–78, 80–82, 125, 386, 435–436 PCF WP, 272, 279–283, 286, 385–388 SP WP, 265, 268 UD, 34–36, 386 ZD, 388 Pleiades, 52, 120, 151, 156, 163, 170, 172, 204, 229, 247, 264, 272, 276, 282, 283, 286, 288, 291, 440, 472, 479, 504, 509 Porro, I., 28 Porro prism, 29 Porro I, 19, 351 Porro II, 19 R Range-finding binoculars Canon, 37, 84, 184, 185, 314–320, 438, 447 Leica, 241, 242, 244 Nikon, 237 Opticron, 23, 37–41, 57, 79, 80, 84–88, 90–94, 114–116, 123, 180, 208–211, 220–221, 229, 269–273, 281, 299, 322–323, 367–370, 436–437, 461, 466–470 Zeiss, 243, 244 Rigel, 52, 90 Rolling ball effects, 86, 110, 116, 135, 147, 172, 183, 204, 210, 228, 336, 349, 356, 357 Roof prism, xi, 3, 4, 18, 20–25, 29–31, 35, 54, 77–80, 84–86, 90–95, 106, 107, 114, 120, 126, 137, 138, 146, 147, 149, 152–153, 155, 156, 159, 164, 166, 174, 176, 177, 182, 198, 211, 214, 220, 223, 225–226, 231, 249, 264, 265, 267–270, 273, 276, 281, 301, 309, 311, 319, 330, 346, 352, 355, 356, 361, 368–370, 376, 381, 388, 391, 393, 394, 399, 402, 420, 434, 435, 437, 452, 462, 466, 468, 470, 473–475, 485–487, 492 S Schmidt Pechan prism, 24, 25, 56, 100, 106, 196, 198, 223, 227, 231, 241, 277, 310, 332, 341, 342, 364, 373, 376, 382

Index Stars color, 52, 247, 259, 272, 284, 450 double, 52, 257, 273, 282, 292, 293, 452 multiple, 273, 452 Steiner, 30, 206, 307–309, 473 Stereopsis, 21–23, 87, 93–94, 105, 264, 270, 310 Svbony SV202, 95–99, 159, 160, 164–166, 274 Swarovski CL Companion, 141, 142, 347 CL Pocket, 43, 44, 51, 56, 61, 65, 67, 346 Curio, 47, 65–67, 74, 347–348 EL-, 54, 142, 143, 166, 183, 187, 211–213, 232, 244–246, 301, 336, 345, 346, 349–350 NL Pure, 123–124, 142–144, 154, 200, 212, 213, 232, 245, 346, 350, 496 SLC, 231, 232, 346, 348–349 Swift, 233, 482–485, 498, 499 T The Moon, 10, 27, 40, 48, 52, 56, 59, 81, 87, 110, 113, 115, 128, 134, 145, 162, 170, 178, 182, 191, 192, 203, 204, 210, 247, 248, 253, 257, 258, 262, 268, 272, 275, 276, 285, 286, 288, 290, 294, 420, 426, 437, 440, 457, 458, 479, 489, 497, 505, 506 Tripod, 10, 35, 39, 44, 78, 81, 86, 111, 163, 176, 186, 187, 220–222, 226, 227, 242, 243, 251, 257–259, 267–269, 276, 277, 281, 282, 287, 288, 291, 293, 294, 296–298, 305, 320, 321, 348, 382, 390, 392, 394, 410–415, 428, 435, 440, 466, 479, 497, 498 V Vega, 52, 80, 119, 162, 170, 210, 221, 229, 267, 276, 290 Vortex Diamondback HD, 100, 101, 159, 196, 260–262, 273, 359–362 Fury, 238, 239 Razor, 196, 197, 361, 362 Viper HD, 196–197, 361 Z Zeiss Antifog, 410 Carl, 29, 243, 339, 363, 462, 463, 470

Index Conquest HD, 136, 137, 194, 230, 342 Delactis, 15, 500 Jenoptem, 84, 340, 462–466, 470, 472, 478, 494 SFL, 139, 140, 343, 344

523 Terra ED, 49, 50, 52, 53, 56, 58, 74, 80, 97, 136, 160, 193, 194, 340–342, 432 Victory SF, 135, 137–140, 161, 201, 214, 332, 343, 344, 363, 487 Wipes, 406, 409