Bird Watching Binoculars Buying Guide

Bird Watching Binoculars Buying Guide

In this guide we cover

What To Look For In a Birding Binocular?

Whether you’re buying your first pair of birding binoculars, or looking to upgrade an existing pair, shopping for binoculars today can be a bewildering experience. With so many options to consider, and so many models to choose from, where on earth do you start?

Here at Stealth Birding, we know binoculars, and we’ve pooled our knowledge and expertise to bring you this handy binocular buyers guide. We cut through the marketing hype and technical jargon, providing exactly what you need to make an informed decision about the right birding binocular for you.

Focus On Your Ideal Binocular

When shopping for binoculars it’s vital to remember that the relationship between a birder and his or her optics is a very personal one. What’s perfect for me may not suit you at all, and vice versa. There really is no such thing as one universally ideal birding binocular -- it’s all about finding that elusive blend of features and performance that suits your particular needs within your budget.

As you consider the rest of the points in this guide, always bear that in mind, and apply the advice based on what you need from your binocular.

Types Of Binocular: Porro Prism Versus Roof Prism

Perhaps the first thing to decide when narrowing down the field of possible binoculars on your shortlist is to select the type you’d like to buy. Binoculars today fall into two main types:

Porro Prism Binoculars

This is the traditional binocular design where the eyepiece lenses are closer together than the objective lenses (the large lenses at the end of each barrel). Prior to the 1960s all binoculars were made this way. In recent times though Porro Prism binoculars are very rairly used by serious birders. This is because they are usually bulkier and ergonomically less comfortable to hold and carry than roof prism binoculars. They are also usually less robust than roof prism binoculars.

Roof Prism Binoculars

This more contemporary, straight-barrelled design results in a more compact, sleek looking binocular that is more robust and ergonomic.

  • Because of the straight barrels, roof prisms are generally more compact and are more comfortable to use and carry for extended periods than porro prisms.
  • Roof prisms tend to be more robust: sealed, nitrogen-purged metal or polycarbonate barrels, often covered in rubber armouring, mean your optical investment is well protected.

Which option you choose is a matter of personal preference, if you’re willing to invest a little more, a high-quality roof prism binocular will generally prove a more versatile all-rounder for birding and wildlife observation in the field.

NB. All of the high-end birding binoculars from leading manufacturers employ roof prism designs.

An example of roof prism binoculars are the Avalon 10x42 PRO HD Binoculars

Avalon 10x42 PRO HD Binoculars

These Binoculars Are Available

In Both Black And White

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Binocular Magnification: Bigger Is Not Always Better

Every binocular has two numbers printed somewhere on the instrument (10x42, 8x32, etc.) -- the first of these numbers (before the x) signifies how much the binocular will magnify the view you’re looking at.

A pair of Bresser Binoculars showing the 10×42 (10x Magnification, 42mm objective lens) printed on the focus wheel.

The higher the magnification, the smaller the field of view

 

Many first-time binocular buyers make the mistake of assuming that higher magnification is better. After all, the whole point of a binocular is to give you a closer view of your subject, so surely more magnification is a good thing.

Unfortunately, when it comes to optics nothing is ever that simple. While higher magnifications will bring your subject closer, they will also reduce image brightness, decrease focus depth, reduce your field of view and accentuate hand-shake and atmospheric aberration. Magnifying hand-shake can be a real issue, particularly as we get older, so for many people, lower magnifications actually work better.

The sweet-spot for birding and wildlife watching binoculars you can comfortably hand-hold in the field and that can be used in a variety of different habitats, falls between 7x-12x, with 8x and 10x being by far the most popular variants.

Binocular Brightness

Image brightness is one of the most important things to consider when choosing your new birding binoculars. Birds are often active in the early morning or late evening when the light is subdued. Even in the middle of the day, in shady habitats like woodland, light is often in short supply, so you’ll need a binocular that can deliver a bright, clear image in poor light.

The principal factors governing brightness in a binocular are the diameter of the objective lens (the second number after the x printed somewhere on the binocular) and the magnification.

Objective lens diameter: more light in = more light out

Larger objective lenses let more light into the optical system… so binoculars with larger objective lenses have the potential to deliver a brighter image at the eyepiece than those with smaller objectives. There’s a caveat though: as you increase the size of the objective lenses binoculars become steadily bulkier, heavier and more expensive.

In practice, for a binocular you want to carry with you and use in the field, the useful range of objective lens sizes is from 30mm-50mm, with 32mm (mid-size binoculars) and 42mm (full-size binoculars) being the most popular. Smaller “pocket” or “compact” binoculars can be useful in situations where you can’t carry a larger binocular, but are not really suitable as an all-round birding binocular.

Field of View

Binoculars with a wide field of view have a number of advantages for birders. A wider field of view makes it easier to scan large open areas quickly, and makes it much easier to find and follow fast, erratically moving subjects like small birds.

Higher magnification reduces the field of view, but a lot of other factors in the optical design can also influence it. Field of view is measured either as an angle (typically between 6°and 8°) or as a linear measurement of how many metres are visible across the diameter of the field at a range of 1,000 metres (or feet/1,000 yards) and is usually printed somewhere on the binocular.

Optical Quality

The optical design, the quality of optical components and the precision of their manufacture all have a huge impact on the quality of the overall image you see through a pair of binoculars. Here are some of the factors that contribute to the overall quality of the view through your binoculars… and features you should look out for when choosing your next birding binocular.

ED or HD Glass

ED (Extra-low Dispersion) or HD (High Density) elements in the objective lenses of some high-performance binoculars are designed to improve resolution and contrast by reducing or eliminating a phenomenon known as Chromatic Aberration (CA), which can cause a bright colour fringing to appear around high-contrast subjects when you look through binoculars

Images through binoculars with ED/HD elements in their optical system tend to appear crisper, more defined and have truer colour fidelity across the spectrum -- resulting in a more natural, realistic image that’s ideal for birding.

A popular ED binocular are the GPO Passion ED Binoculars

GPO Passion ED Binoculars

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Close Focus

Another aspect of the optical design that it’s important to consider is how close your binoculars can achieve sharp focus. Most contemporary binoculars will focus as close as 2m or closer… but some, particularly at the lower end of the market, may have a specified close-focus distance of 3m or more, and some can focus as close as 1.5m or less.

Generally, for birding, 3m isn’t an issue, but if you’re likely to use your binoculars to look at insects (dragonflies and butterflies, for example) or to get a closer look at inaccessible wildflowers on the far side of a ditch or fence, then close-focus could be more important for you.

Lens and Prism Coatings

High performance anti-reflective, high-transmission coatings are critical to the design and performance of contemporary optics. The quality of the optical coatings is one of the key differentiators between mediocre binoculars and truly outstanding ones.

All binoculars on the market today employ some form of coating on the lenses and prisms to improve light transmission and reduce internal reflection. These coatings vary enormously from manufacturer to manufacturer, and at different price-points in the marketplace, but broadly speaking binoculars sold today are either:

  • Coated: some, but not all air-to-glass surfaces in the optical system have a special coating applied to them.
  • Fully-coated: all air-to-glass surfaces in the binocular have a special coating applied to them
  • Multi-coated: some air-to-glass surfaces in the binocular have multiple layers of coating applied to them
  • Fully-multi-coated: all air-to-glass surfaces in the binocular have multiple layers of coating applied to them

For serious birding and wildlife observation NEVER consider buying anything but fully-multi-coated optics.

Anti Reflection, High Transmission Coatings

By applying layers of anti-reflection, high-transmission coatings to optical surfaces, manufacturers optimise the transmission of visible light through the binocular’s optical system, minimising internal reflection, and delivering a brighter, sharper more defined image at the eyepiece. The very best anti-reflection coatings are expensive and technically difficult to apply evenly, adding considerably to the cost of the finished binocular, but dramatically improving its performance.

Phase Corrected Roof Prism Coatings

The way roof prism binoculars work means that the light passing through the optical system is split and then recombined as it passes through the prism system. These separate light paths end up “out of phase” with one another, resulting in less contrast and detail in the recombined image.

To combat this “Phase Shift” good roof prism binoculars will have a special Phase Correction coating applied to the prism surface to correct this phenomenon.

Roof Prism Mirror Coatings

The roof prism design also requires a special reflective mirror coating applied to one of the prism surfaces to reflect light through the prism system to the eyepiece. The higher the light transmission of this mirror coating, the brighter the binocular will appear in low light situations.

The three most commonly applied mirror coatings, in order of increasing brightness (and cost), are:

  • Aluminium mirror coating: typically result in light transmission of 87-93% through the prism.
  • Silver mirror coating: result in light transmission of 95-98% through the prism.
  • Dielectric mirror coating: a special coating technique used in very high specification binoculars to achieve >99% light transmission through the prism.

Protective/Water Repellent Coatings

Premium binoculars often have a special high-tech coating applied to external lens surfaces designed to protect the more fragile coatings underneath. These coatings are very tough, to resist abrasion and scratching, and actively repel water and dirt particles, meaning your lenses need cleaning less often, and are much easier to clean when the need arises.

This feature that’s starting to appear in some mid-market binoculars now -- and where available within your budget is something to consider.

Weatherproofing

Binoculars for birding have to be able to cope with whatever the weather can throw at them. Make sure the binoculars you choose are waterproof and fully sealed. As well as protecting against rain, or accidental immersion, this will also mean your binoculars are impervious to dust and other airborne contaminants.

It’s also important to ensure your binoculars have been purged with an inert gas (usually nitrogen but occasionally argon) at the factory. This drives out the air (and the water vapour it contains), eliminating the risk of internal condensation/fogging as your move between dramatically different temperatures (from a warm car, for example, to a freezing lakeshore, or vice versa).

Balance, Handling and Durability

How comfortable a binocular is to hold and carry has a big impact on your enjoyment when using it. The size and shape of binocular you prefer is largely a matter of personal preference. Because of constraints imposed by the optical design, porro prism binoculars tend to come in a variant of the traditional porro prism design we’re all familiar with. When it comes to roof-prism binoculars, however, you have more choice in terms of style.

Traditional Single-bridge

The original roof-prism design with a single wide hinge joining the two binocular barrels spanning most of the binoculars length. An example of the single bridge design are the Kite Caiman Binoculars.

Kite Caiman Binoculars

Available In Either

8 Or 10 Magnification

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Open-bridge / Double-hinge

The barrels are joined by two hinges, one high on the barrels close to the eyepiece, and one close to the end of the barrels leaving the middle of the barrels exposed for a “wrap-around” grip that many people find more comfortable. An example of the open bridge design are the Avalon Titan ED Binoculars.

Avalon Titan ED Binoculars

Available In Either

8 Or 10 Magnification

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A Word About Weight

The weight of a binocular will, of course, depend on its size, but also on the type of housing/body material used in its construction, and the quality of the optical components it contains. It’s important to remember that while keeping weight down is important, high-quality optical glass is dense and heavy. Binoculars that seem unusually light for their size should ring warning bells about the quality of the optical components inside.

Having a reasonable amount of weight in a birding binocular is desirable for another reason. A bit of weight, and the inertia that comes with it, often helps dampen some of the effects of hand-shake. Counterintuitively, and within reason, weightier binoculars tend to be easier to hold steady than very light ones.

Housing & Rubber Armour

One of the principal components that adds weight to a binocular is the body or housing material. It is also the key component that protects the delicate optical system from the knocks and bangs that are a fact of life out in the field.

So binocular housings need to be lightweight, but they also need to be very strong. The quest for that elusive balance between weight and durability has led to three key materials being used in contemporary binocular construction:

  • Polycarbonate: light, very strong and relatively low cost, polycarbonate bodies are typically used in many budget- to mid-range binoculars
  • Aluminium alloy: light and very strong metal, many manufacturers employ aluminium alloys in the construction of their mid- to high-range binoculars
  • Magnesium alloy: the strongest, lightest and most expensive material currently used for binocular housings, magnesium alloy is generally used on premium models from high end optics manufacturers.

As well as a solid housing almost all contemporary binoculars will have some degree of rubber armour applied to both barrels to protect against minor impact in the field, and also to improve grip and comfort for the user. Sometimes armour will include sculpted thumb indents and textured surfaces to improve the grip and handling of the binocular.

Eye Cups and Eye Relief

 

Contemporary binoculars feature adjustable eyecups to make viewing more comfortable. Older or cheaper models will have rubber eyecups that can be folded up or down, whereas newer, higher quality models will have plastic or metal rubber-coated eye-cups that twist up and down as required, often with intermediary “click-stop” points in between.

Eye cups help you to hold the binoculars at exactly the right distance from your eyes to see the full field of view comfortably, and shade out external light. For users wearing eye glasses, these eyecups can be twisted all the way down to bring their eyes closer to the eyepieces and allow them to see the full field of view while still wearing their glasses.

Eye Relief

The eye-relief of an optical instrument refers to the maximum distance behind the eyepiece that a user can place his or her eye and still see the full etent of the field of view. When viewing without glasses, you can position your eye wherever is most comfortable within this range (by setting the twist-up eyecups to your preferred height).

For those who need to wear their glasses when using binoculars, having enough eye relief can be critical. Because the glasses have to sit between the binocular eyepiece and the viewer’s eyes, eyeglass wearers need a binocular with sufficient eye-relief to accommodate the thickness of their glasses, and the distance between the inside lens surface of their glasses and their eye, in order to see the full field of view.

If you wear glasses pay particular attention to the eye relief quoted in a binocular’s specs. Long-eye-relief binoculars with a quoted eye-relief measurement of 16mm or more should work well for most eyeglass wearers… however some may find they require a eye relief of up to 18mm or even more to experience the full field of view.

Setting Your Budget - Think Value, Not Price

When deciding how much to spend on your new birding binoculars, it’s important to remember that the cheapest option almost never represents the best value. Investing a bit more in a quality optical instrument is always worth it.

Binoculars are probably the single most important piece of equipment a birder will own. They are something you will use regularly (perhaps every day), and that will continue to repay your investment with exceptional views for many years. Our advice is always to buy the best pair of binoculars you can realistically afford: then to get out and enjoy them, every chance you get.

Below are the 6 binoculars we believe offer the best value

All sizes of the 6 binoculars recommended in this guide are waterproof and fog proof.


Binoculars are listed in price order starting with the lowest

Please View Our Choices below

All binoculars in this list include free binocular harness which usually costs £50

Stealth Birding Quick Release Binocular Harness

The Stealth Birding Quick Release Harness secures your binoculars to your torso, preventing them from bouncing about as you walk, and ideally distributing the weight. This ensures it is always comfortable to carry your binoculars, especially when out on a birding trip.

 

Bresser Condor Binoculars

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Consisting of six different roof prism models, spread between four different size categories, the Bresser Condor series can be summarised as a diverse, affordable mid-level range of binoculars with an excellent performance to cost ratio.

 

Particularly notable at this price point are the number of metal components used and the high level of optical glass and coatings which directly contributes to their class-leading performance.

 

Built around a single bridge body shape all Condor binoculars have a lightweight polycarbonate housing commonly found at this price point because it is relatively low cost to make, yet is robust, lightweight and completely resistant to corrosion.

 

All models also have a large, easy to reach central focus wheel, comfortable twist-up eyecups with intermediate click stops and a right eye diopter adjustment to calibrate the binocular to match your particular eyesight. Unlike many binoculars at this price range, Bresser has chosen to use aluminium and not plastic for these components. Not only does this look great, but they are more robust and generally have a far nicer action.

 

The level of optics incorporated into all Bresser Condor binoculars is very impressive at this price range: The whole optical system is fully multi-coated with anti-reflective coatings that reduce undesired reflections as well as increase light transmission resulting in brighter, more defined images.

 

Roof prisms are made from quality BaK-4 glass and are phase-corrected. As well as this, Bresser uses their Silver "Ultimate Reflection Coatings" prisms which certainly contributes to a brighter, better quality view.

 

The warranty on these binoculars is an impressive 30-years. After you register the binoculars online you are then guaranteed for life.


Bresser Pirsch Binoculars

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The full range of Bresser Pirsch binoculars range from the 8x26 magnification option all the way up to the 8x56 model. They come with standout features that add elegance and practicality.

Each set has a stunningly simple matt green finish on the outside, and they are all relatively lightweight enough to be useful on any camping trip or hiking expedition.

They have several key features that will give crystal clear viewing quality for their entire lifetime. The nitrogen purged internals paired with the brilliant phase coating allow second to none view quality that will never disappoint.

You can choose from multiple magnifications and lens sizes to suit your needs.
The compact 26mm and 34mm models are great for a cheaper, pocket sized option.
The 42mm binoculars provide a wider image, but can still be easily carried along on any trip. For the best low light performance however, the 8x56 model is a brilliant option that balances price and view quality perfectly.

Between the design features, the aesthetics and the included extras, these binoculars truly are a beautiful set and their quality is well worth their price.

The warranty on these binoculars is an impressive 30-years. After you register the binoculars online you are then guaranteed for life.


Bresser Pirsch ED Binoculars

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Containing five different models, spread between three different size categories, the Pirsch ED series of roof prism binoculars from Bresser is aimed at the more serious observer looking for a professional level instrument, but also with an excellent price to performance ratio.

 

Based around an open bridge body design that reduces weight and frees up more space on the barrels and thus offers a more secure area with which to hold onto.

 

All models in this series have a large, centrally located focus wheel, click-stop twist-up eyecups and a right eye diopter enabling you to calibrate the instrument to your particular vision.

 

As the name suggests, all Bresser Pirsch “ED” binoculars incorporate ED or extra-low dispersion glass elements within their lenses. This enables them to better direct each of the wavelengths of light as they pass through the lenses and results in less colour fringing along the edges of objects in the view.

 

As well as this, the entire optical system is fully multi-coated with anti-reflective coatings that increase light transmission by reducing undesired reflections for brighter, higher-definition images.

 

Made from high-quality BaK-4 glass, the Schmidt-Pechan roof prisms not only contain phase-correction coatings that further improve image definition, but they also use the very best dielectric mirror coatings. With more than 99% reflectivity, they ensure as much light reaches your eyes for as bright an image as possible.

 

The warranty on these binoculars is an impressive 30-years. After you register the binoculars online you are then guaranteed for life.


GPO Passion ED Binoculars

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GPO stands for German Precision Optics. Their products are built to high-quality standards.

PASSION™ ED binoculars offer the perfect entry into the world of high-quality observation optics at an unbeatable price-performance ratio. The sleek and ergonomic design has been combined with the use of high quality materials. The entire housing is made of pure magnesium. Thanks to ED lenses, multi-layer coatings and adapted optics, they offer a wide field of view, high edge-to-edge sharpness and transmission values as well as a shortened close focus. Their robustness and optical performance make them unique performers in their class.

PASSION ED binoculars are built to the highest standards within their price class, and in the same factories as other European brands. Their unique magnesium body makes them ultra lightweight yet incredibly durable, and their cutting edge field of view makes these binoculars an instant classic among outdoor enthusiasts.

The lenses on these binoculars feature ED glass elements. The extra-low dispersion properties of this high-quality glass enable them to better direct the individual wavelengths of light so that an even higher resolution image is possible.

As well as the ED glass system these binoculars includes GPObright lens coating technology. GPObright is a proprietary coating process that maximizes light transmission through each surface of an optical element. As light hits an optical surface, normal uncoated high-performance glass can reflect up to 5% of that light, redirecting this light so it does not transmit through the optical system. However, when these high-performance lenses are vacuum-coated with GPObright lens coatings, up to 99.7% of the available light passes through each optical surface. Furthermore, when every surface of the entire optical system is properly coated, total light transmission can reach up to more than 92%, making the optical image of a GPO binocular “bright,” even in the lowest light conditions.

The 32mm models are GPO most compact, lightweight binoculars yet sacrifice next to nothing in terms of optical performance and durability. The 42mm models provide big-time performance in a compact, lightweight package. Ideal for all outdoor enthusiasts.

Completing the package is German Precision Optics Lifetime Warranty that not only comprehensively protects you, but also demonstrates the complete confidence that they have in their instruments.


Kite Lynx HD + Binoculars

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With five separate models, split into between three different size categories, Kite Lynx HD+ binoculars incorporate a very high level of optical components, coatings and body parts and are aimed at those needing a professional level instrument to do more than simply get the job done.

 

Based around a single, “top-hinge” body design and with a tough outer rubber armour, all models are not only comfortable and secure to hold onto but the optics contained within are well-protected.

 

Going even further, the outer lenses surfaces have also been treated with a hardened, scratch resistant as well as water and dirt repelling material for further protection and ensuring you are able to enjoy the best possible view no matter the conditions.

 

As well as these protective coatings, the ED + optical system used on these binoculars includes multiple anti-reflection coatings on all air to glass surfaces and highly reflective phase-corrected Schmidt-Pechan roof prisms enabling them to produce extremely bright, high-definition views even in low light situations.

 

All Kite Lynx HD + binoculars feature a large, centrally located focus wheel, multi-position twist-up eyecups and a right eye diopter ensuring a perfect match for your particular vision.

 

Completing this incredibly impressive package is the equally impressive 30-year guarantee highlighting the incredible level of confidence Kite Optics has in these instruments.


GPO Passion HD Binoculars

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GPO stands for German Precision Optics. Their products are built to high-quality standards.

GPO PASSION™ HD binoculars represent the absolute premium class from GPO. HD/ED optical design combined with state-of-the-art multi-layer coatings creates optical excellence in transmission, field of view, edge-to-edge sharpness, close focus and color reproduction. Thanks to our hydrophobic coating PASSIONdrop™ all optics are dirt and water repellent. The innovative microbridge offers a high quality and very ergonomic design. Magnesium housing, coated magnesium bridge and the fully machined aluminium rotary eyecups provide maximum ruggedness with minimal weight. The diopter adjustment was integrated in the central focusing wheel to provide comfortable ease of use. If you do not want to compromise on the quality of your binoculars and are looking for an extremely fair price-performance ratio, you will find it here.

The lenses on these binoculars feature Double ED/HD Double Lens glass elements. This special glass is created when multiple extra-low dispersion lenses are chemically laminated to make a single, multilayer high-performance optical lens. Laminating multiple lenses minimizes light reflection on the surface of multiple lenses, creates enhanced resolution and color contrast images, and minimizes chromatic aberrations. This benefit is clearly visible with all GPO products supporting this feature. This high-performance process is routinely found in the photographic market and with the highest quality photographic lens manufacturers, but has now transitioned into premium sporting optics.

These binoculars include GPObright lens coating technology. GPObright is a proprietary coating process that maximizes light transmission through each surface of an optical element. As light hits an optical surface, normal uncoated high-performance glass can reflect up to 5% of that light, redirecting this light so it does not transmit through the optical system. However, when these high-performance lenses are vacuum-coated with GPObright lens coatings, up to 99.7% of the available light passes through each optical surface. Furthermore, when every surface of the entire optical system is properly coated, total light transmission can reach up to more than 92%, making the optical image of a GPO binocular “bright,” even in the lowest light conditions.

The 42mm models are compact, lightweight and high-quality options for all your outdoor needs. The 50mm models are characterized by large objective lenses to allow for higher light transmission for the most challenging light conditions.

Completing the package is German Precision Optics Lifetime Warranty that not only comprehensively protects you, but also demonstrates the complete confidence that they have in their instruments.


In this guide we cover

What To Look For In a Birding Binocular?

Whether you’re buying your first pair of birding binoculars, or looking to upgrade an existing pair, shopping for binoculars today can be a bewildering experience. With so many options to consider, and so many models to choose from, where on earth do you start?

Here at Stealth Birding, we know binoculars, and we’ve pooled our knowledge and expertise to bring you this handy binocular buyers guide. We cut through the marketing hype and technical jargon, providing exactly what you need to make an informed decision about the right birding binocular for you.

Focus On Your Ideal Binocular

When shopping for binoculars it’s vital to remember that the relationship between a birder and his or her optics is a very personal one. What’s perfect for me may not suit you at all, and vice versa. There really is no such thing as one universally ideal birding binocular -- it’s all about finding that elusive blend of features and performance that suits your particular needs within your budget.

As you consider the rest of the points in this guide, always bear that in mind, and apply the advice based on what you need from your binocular.

Types Of Binocular: Porro Prism Versus Roof Prism

Perhaps the first thing to decide when narrowing down the field of possible binoculars on your shortlist is to select the type you’d like to buy. Binoculars today fall into two main types:

Porro Prism Binoculars

This is the traditional binocular design where the eyepiece lenses are closer together than the objective lenses (the large lenses at the end of each barrel). Prior to the 1960s all binoculars were made this way. In recent times though Porro Prism binoculars are very rairly used by serious birders.

This is because they are usually bulkier and ergonomically less comfortable to hold and carry than roof prism binoculars. They are also usually less robust than roof prism binoculars.

Roof Prism Binoculars

This more contemporary, straight-barrelled design results in a more compact, sleek looking binocular that is more robust and ergonomic.

  • Because of the straight barrels, roof prisms are generally more compact and are more comfortable to use and carry for extended periods than porro prisms.
  • Roof prisms tend to be more robust: sealed, nitrogen-purged metal or polycarbonate barrels, often covered in rubber armouring, mean your optical investment is well protected.

Which option you choose is a matter of personal preference, if you’re willing to invest a little more, a high-quality roof prism binocular will generally prove a more versatile all-rounder for birding and wildlife observation in the field.

NB. All of the high-end birding binoculars from leading manufacturers employ roof prism designs.

An example of roof prism binoculars are the Avalon 10x42 PRO HD Binoculars

Avalon 10x42 PRO HD Binoculars

These Binoculars Are Available

In Both Black And White

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Binocular Magnification: Bigger Is Not Always Better

Every binocular has two numbers printed somewhere on the instrument (10x42, 8x32, etc.) -- the first of these numbers (before the x) signifies how much the binocular will magnify the view you’re looking at.

A pair of Bresser Binoculars showing the 10×42 (10x Magnification, 42mm objective lens) printed on the focus wheel.

The higher the magnification, the smaller the field of view

Many first-time binocular buyers make the mistake of assuming that higher magnification is better. After all, the whole point of a binocular is to give you a closer view of your subject, so surely more magnification is a good thing.

Unfortunately, when it comes to optics nothing is ever that simple. While higher magnifications will bring your subject closer, they will also reduce image brightness, decrease focus depth, reduce your field of view and accentuate hand-shake and atmospheric aberration. Magnifying hand-shake can be a real issue, particularly as we get older, so for many people, lower magnifications actually work better.

The sweet-spot for birding and wildlife watching binoculars you can comfortably hand-hold in the field and that can be used in a variety of different habitats, falls between 7x-12x, with 8x and 10x being by far the most popular variants.

Binocular Brightness

Image brightness is one of the most important things to consider when choosing your new birding binoculars. Birds are often active in the early morning or late evening when the light is subdued.

Even in the middle of the day, in shady habitats like woodland, light is often in short supply, so you’ll need a binocular that can deliver a bright, clear image in poor light.

The principal factors governing brightness in a binocular are the diameter of the objective lens (the second number after the x printed somewhere on the binocular) and the magnification.

Objective lens diameter: more light in = more light out

Larger objective lenses let more light into the optical system… so binoculars with larger objective lenses have the potential to deliver a brighter image at the eyepiece than those with smaller objectives. There’s a caveat though: as you increase the size of the objective lenses binoculars become steadily bulkier, heavier and more expensive.

In practice, for a binocular you want to carry with you and use in the field, the useful range of objective lens sizes is from 30mm-50mm, with 32mm (mid-size binoculars) and 42mm (full-size binoculars) being the most popular. Smaller “pocket” or “compact” binoculars can be useful in situations where you can’t carry a larger binocular, but are not really suitable as an all-round birding binocular.

Field of View

Binoculars with a wide field of view have a number of advantages for birders. A wider field of view makes it easier to scan large open areas quickly, and makes it much easier to find and follow fast, erratically moving subjects like small birds.

Higher magnification reduces the field of view, but a lot of other factors in the optical design can also influence it. Field of view is measured either as an angle (typically between 6°and 8°) or as a linear measurement of how many metres are visible across the diameter of the field at a range of 1,000 metres (or feet/1,000 yards) and is usually printed somewhere on the binocular.

Optical Quality

The optical design, the quality of optical components and the precision of their manufacture all have a huge impact on the quality of the overall image you see through a pair of binoculars. Here are some of the factors that contribute to the overall quality of the view through your binoculars… and features you should look out for when choosing your next birding binocular.

ED or HD Glass

ED (Extra-low Dispersion) or HD (High Density) elements in the objective lenses of some high-performance binoculars are designed to improve resolution and contrast by reducing or eliminating a phenomenon known as Chromatic Aberration (CA), which can cause a bright colour fringing to appear around high-contrast subjects when you look through binoculars

Images through binoculars with ED/HD elements in their optical system tend to appear crisper, more defined and have truer colour fidelity across the spectrum -- resulting in a more natural, realistic image that’s ideal for birding.

A popular ED binocular are the GPO Passion ED Binoculars

GPO Passion ED Binoculars

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Close Focus

Another aspect of the optical design that it’s important to consider is how close your binoculars can achieve sharp focus.

Most contemporary binoculars will focus as close as 2m or closer… but some, particularly at the lower end of the market, may have a specified close-focus distance of 3m or more, and some can focus as close as 1.5m or less. Generally, for birding, 3m isn’t an issue, but if you’re likely to use your binoculars to look at insects (dragonflies and butterflies, for example) or to get a closer look at inaccessible wildflowers on the far side of a ditch or fence, then close-focus could be more important for you.

Lens and Prism Coatings

High performance anti-reflective, high-transmission coatings are critical to the design and performance of contemporary optics. The quality of the optical coatings is one of the key differentiators between mediocre binoculars and truly outstanding ones.

All binoculars on the market today employ some form of coating on the lenses and prisms to improve light transmission and reduce internal reflection. These coatings vary enormously from manufacturer to manufacturer, and at different price-points in the marketplace, but broadly speaking binoculars sold today are either:

  • Coated: some, but not all air-to-glass surfaces in the optical system have a special coating applied to them.
  • Fully-coated: all air-to-glass surfaces in the binocular have a special coating applied to them
  • Multi-coated: some air-to-glass surfaces in the binocular have multiple layers of coating applied to them
  • Fully-multi-coated: all air-to-glass surfaces in the binocular have multiple layers of coating applied to them

For serious birding and wildlife observation NEVER consider buying anything but fully-multi-coated optics.

Anti Reflection, High Transmission Coatings

By applying layers of anti-reflection, high-transmission coatings to optical surfaces, manufacturers optimise the transmission of visible light through the binocular’s optical system, minimising internal reflection, and delivering a brighter, sharper more defined image at the eyepiece. The very best anti-reflection coatings are expensive and technically difficult to apply evenly, adding considerably to the cost of the finished binocular, but dramatically improving its performance.

Phase Corrected Roof Prism Coatings

The way roof prism binoculars work means that the light passing through the optical system is split and then recombined as it passes through the prism system. These separate light paths end up “out of phase” with one another, resulting in less contrast and detail in the recombined image.

To combat this “Phase Shift” good roof prism binoculars will have a special Phase Correction coating applied to the prism surface to correct this phenomenon.

Roof Prism Mirror Coatings

The roof prism design also requires a special reflective mirror coating applied to one of the prism surfaces to reflect light through the prism system to the eyepiece. The higher the light transmission of this mirror coating, the brighter the binocular will appear in low light situations.

The three most commonly applied mirror coatings, in order of increasing brightness (and cost), are:

  • Aluminium mirror coating: typically result in light transmission of 87-93% through the prism.
  • Silver mirror coating: result in light transmission of 95-98% through the prism.
  • Dielectric mirror coating: a special coating technique used in very high specification binoculars to achieve >99% light transmission through the prism.

Protective/Water Repellent Coatings

Premium binoculars often have a special high-tech coating applied to external lens surfaces designed to protect the more fragile coatings underneath. These coatings are very tough, to resist abrasion and scratching, and actively repel water and dirt particles, meaning your lenses need cleaning less often, and are much easier to clean when the need arises.

This feature that’s starting to appear in some mid-market binoculars now -- and where available within your budget is something to consider.

Weatherproofing

Binoculars for birding have to be able to cope with whatever the weather can throw at them.

Make sure the binoculars you choose are waterproof and fully sealed. As well as protecting against rain, or accidental immersion, this will also mean your binoculars are impervious to dust and other airborne contaminants.

It’s also important to ensure your binoculars have been purged with an inert gas (usually nitrogen but occasionally argon) at the factory. This drives out the air (and the water vapour it contains), eliminating the risk of internal condensation/fogging as your move between dramatically different temperatures (from a warm car, for example, to a freezing lakeshore, or vice versa).

Balance, Handling and Durability

How comfortable a binocular is to hold and carry has a big impact on your enjoyment when using it. The size and shape of binocular you prefer is largely a matter of personal preference. Because of constraints imposed by the optical design, porro prism binoculars tend to come in a variant of the traditional porro prism design we’re all familiar with. When it comes to roof-prism binoculars, however, you have more choice in terms of style.

Traditional Single-bridge

The original roof-prism design with a single wide hinge joining the two binocular barrels spanning most of the binoculars length. An example of the single bridge design are the Kite Caiman Binoculars.

Kite Caiman Binoculars

Available In Either

8 Or 10 Magnification

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Open-bridge / Double-hinge

The barrels are joined by two hinges, one high on the barrels close to the eyepiece, and one close to the end of the barrels leaving the middle of the barrels exposed for a “wrap-around” grip that many people find more comfortable. An example of the open bridge design are the Avalon Titan ED Binoculars.

Avalon Titan ED Binoculars

Available In Either

8 Or 10 Magnification

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A Word About Weight

The weight of a binocular will, of course, depend on its size, but also on the type of housing/body material used in its construction, and the quality of the optical components it contains. It’s important to remember that while keeping weight down is important, high-quality optical glass is dense and heavy. Binoculars that seem unusually light for their size should ring warning bells about the quality of the optical components inside.

Having a reasonable amount of weight in a birding binocular is desirable for another reason. A bit of weight, and the inertia that comes with it, often helps dampen some of the effects of hand-shake. Counterintuitively, and within reason, weightier binoculars tend to be easier to hold steady than very light ones.

Housing & Rubber Armour

One of the principal components that adds weight to a binocular is the body or housing material. It is also the key component that protects the delicate optical system from the knocks and bangs that are a fact of life out in the field.

So binocular housings need to be lightweight, but they also need to be very strong. The quest for that elusive balance between weight and durability has led to three key materials being used in contemporary binocular construction:

  • Polycarbonate: light, very strong and relatively low cost, polycarbonate bodies are typically used in many budget- to mid-range binoculars
  • Aluminium alloy: light and very strong metal, many manufacturers employ aluminium alloys in the construction of their mid- to high-range binoculars
  • Magnesium alloy: the strongest, lightest and most expensive material currently used for binocular housings, magnesium alloy is generally used on premium models from high end optics manufacturers.

As well as a solid housing almost all contemporary binoculars will have some degree of rubber armour applied to both barrels to protect against minor impact in the field, and also to improve grip and comfort for the user. Sometimes armour will include sculpted thumb indents and textured surfaces to improve the grip and handling of the binocular.

Eye Cups and Eye Relief

Contemporary binoculars feature adjustable eyecups to make viewing more comfortable.

Older or cheaper models will have rubber eyecups that can be folded up or down, whereas newer, higher quality models will have plastic or metal rubber-coated eye-cups that twist up and down as required, often with intermediary “click-stop” points in between.

Eye cups help you to hold the binoculars at exactly the right distance from your eyes to see the full field of view comfortably, and shade out external light. For users wearing eye glasses, these eyecups can be twisted all the way down to bring their eyes closer to the eyepieces and allow them to see the full field of view while still wearing their glasses.

Eye Relief

The eye-relief of an optical instrument refers to the maximum distance behind the eyepiece that a user can place his or her eye and still see the full etent of the field of view. When viewing without glasses, you can position your eye wherever is most comfortable within this range (by setting the twist-up eyecups to your preferred height).

For those who need to wear their glasses when using binoculars, having enough eye relief can be critical. Because the glasses have to sit between the binocular eyepiece and the viewer’s eyes, eyeglass wearers need a binocular with sufficient eye-relief to accommodate the thickness of their glasses, and the distance between the inside lens surface of their glasses and their eye, in order to see the full field of view.

If you wear glasses pay particular attention to the eye relief quoted in a binocular’s specs. Long-eye-relief binoculars with a quoted eye-relief measurement of 16mm or more should work well for most eyeglass wearers… however some may find they require a eye relief of up to 18mm or even more to experience the full field of view.

Setting Your Budget - Think Value, Not Price

When deciding how much to spend on your new birding binoculars, it’s important to remember that the cheapest option almost never represents the best value. Investing a bit more in a quality optical instrument is always worth it.

Binoculars are probably the single most important piece of equipment a birder will own. They are something you will use regularly (perhaps every day), and that will continue to repay your investment with exceptional views for many years. Our advice is always to buy the best pair of binoculars you can realistically afford: then to get out and enjoy them, every chance you get.

Below are the 6 binoculars we believe offer the best value

All sizes of the 6 binoculars recommended in this guide are waterproof and fog proof.


Binoculars are listed in price order starting with the lowest

Please View Our Choices below

All binoculars in this list include free binocular harness which usually costs £50

Stealth Birding Quick Release Binocular Harness

The Stealth Birding Quick Release Harness secures your binoculars to your torso, preventing them from bouncing about as you walk, and ideally distributing the weight. This ensures it is always comfortable to carry your binoculars, especially when out on a birding trip.

 

Bresser Condor Binoculars

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Consisting of six different roof prism models, spread between four different size categories, the Bresser Condor series can be summarised as a diverse, affordable mid-level range of binoculars with an excellent performance to cost ratio.

 

Particularly notable at this price point are the number of metal components used and the high level of optical glass and coatings which directly contributes to their class-leading performance.

 

Built around a single bridge body shape all Condor binoculars have a lightweight polycarbonate housing commonly found at this price point because it is relatively low cost to make, yet is robust, lightweight and completely resistant to corrosion.

 

All models also have a large, easy to reach central focus wheel, comfortable twist-up eyecups with intermediate click stops and a right eye diopter adjustment to calibrate the binocular to match your particular eyesight. Unlike many binoculars at this price range, Bresser has chosen to use aluminium and not plastic for these components. Not only does this look great, but they are more robust and generally have a far nicer action.

 

The level of optics incorporated into all Bresser Condor binoculars is very impressive at this price range: The whole optical system is fully multi-coated with anti-reflective coatings that reduce undesired reflections as well as increase light transmission resulting in brighter, more defined images.

 

Roof prisms are made from quality BaK-4 glass and are phase-corrected. As well as this, Bresser uses their Silver "Ultimate Reflection Coatings" prisms which certainly contributes to a brighter, better quality view.

 

The warranty on these binoculars is an impressive 30-years. After you register the binoculars online you are then guaranteed for life.


Bresser Pirsch Binoculars

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The full range of Bresser Pirsch binoculars range from the 8x26 magnification option all the way up to the 8x56 model. They come with standout features that add elegance and practicality.

Each set has a stunningly simple matt green finish on the outside, and they are all relatively lightweight enough to be useful on any camping trip or hiking expedition.

They have several key features that will give crystal clear viewing quality for their entire lifetime. The nitrogen purged internals paired with the brilliant phase coating allow second to none view quality that will never disappoint.

You can choose from multiple magnifications and lens sizes to suit your needs.
The compact 26mm and 34mm models are great for a cheaper, pocket sized option.
The 42mm binoculars provide a wider image, but can still be easily carried along on any trip. For the best low light performance however, the 8x56 model is a brilliant option that balances price and view quality perfectly.

Between the design features, the aesthetics and the included extras, these binoculars truly are a beautiful set and their quality is well worth their price.

The warranty on these binoculars is an impressive 30-years. After you register the binoculars online you are then guaranteed for life.


Bresser Pirsch ED Binoculars

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GPO Passion ED Binoculars

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GPO stands for German Precision Optics. Their products are built to high-quality standards.

PASSION™ ED binoculars offer the perfect entry into the world of high-quality observation optics at an unbeatable price-performance ratio. The sleek and ergonomic design has been combined with the use of high quality materials. The entire housing is made of pure magnesium. Thanks to ED lenses, multi-layer coatings and adapted optics, they offer a wide field of view, high edge-to-edge sharpness and transmission values as well as a shortened close focus. Their robustness and optical performance make them unique performers in their class.

PASSION ED binoculars are built to the highest standards within their price class, and in the same factories as other European brands. Their unique magnesium body makes them ultra lightweight yet incredibly durable, and their cutting edge field of view makes these binoculars an instant classic among outdoor enthusiasts.

The lenses on these binoculars feature ED glass elements. The extra-low dispersion properties of this high-quality glass enable them to better direct the individual wavelengths of light so that an even higher resolution image is possible.

As well as the ED glass system these binoculars includes GPObright lens coating technology. GPObright is a proprietary coating process that maximizes light transmission through each surface of an optical element. As light hits an optical surface, normal uncoated high-performance glass can reflect up to 5% of that light, redirecting this light so it does not transmit through the optical system. However, when these high-performance lenses are vacuum-coated with GPObright lens coatings, up to 99.7% of the available light passes through each optical surface. Furthermore, when every surface of the entire optical system is properly coated, total light transmission can reach up to more than 92%, making the optical image of a GPO binocular “bright,” even in the lowest light conditions.

The 32mm models are GPO most compact, lightweight binoculars yet sacrifice next to nothing in terms of optical performance and durability. The 42mm models provide big-time performance in a compact, lightweight package. Ideal for all outdoor enthusiasts.

Completing the package is German Precision Optics Lifetime Warranty that not only comprehensively protects you, but also demonstrates the complete confidence that they have in their instruments.


Kite Lynx HD + Binoculars

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With five separate models, split into between three different size categories, Kite Lynx HD+ binoculars incorporate a very high level of optical components, coatings and body parts and are aimed at those needing a professional level instrument to do more than simply get the job done.

 

Based around a single, “top-hinge” body design and with a tough outer rubber armour, all models are not only comfortable and secure to hold onto but the optics contained within are well-protected.

 

Going even further, the outer lenses surfaces have also been treated with a hardened, scratch resistant as well as water and dirt repelling material for further protection and ensuring you are able to enjoy the best possible view no matter the conditions.

 

As well as these protective coatings, the ED + optical system used on these binoculars includes multiple anti-reflection coatings on all air to glass surfaces and highly reflective phase-corrected Schmidt-Pechan roof prisms enabling them to produce extremely bright, high-definition views even in low light situations.

 

All Kite Lynx HD + binoculars feature a large, centrally located focus wheel, multi-position twist-up eyecups and a right eye diopter ensuring a perfect match for your particular vision.

 

Completing this incredibly impressive package is the equally impressive 30-year guarantee highlighting the incredible level of confidence Kite Optics has in these instruments.


GPO Passion HD Binoculars

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GPO stands for German Precision Optics. Their products are built to high-quality standards.

GPO PASSION™ HD binoculars represent the absolute premium class from GPO. HD/ED optical design combined with state-of-the-art multi-layer coatings creates optical excellence in transmission, field of view, edge-to-edge sharpness, close focus and color reproduction. Thanks to our hydrophobic coating PASSIONdrop™ all optics are dirt and water repellent. The innovative microbridge offers a high quality and very ergonomic design. Magnesium housing, coated magnesium bridge and the fully machined aluminium rotary eyecups provide maximum ruggedness with minimal weight. The diopter adjustment was integrated in the central focusing wheel to provide comfortable ease of use. If you do not want to compromise on the quality of your binoculars and are looking for an extremely fair price-performance ratio, you will find it here.

The lenses on these binoculars feature Double ED/HD Double Lens glass elements. This special glass is created when multiple extra-low dispersion lenses are chemically laminated to make a single, multilayer high-performance optical lens. Laminating multiple lenses minimizes light reflection on the surface of multiple lenses, creates enhanced resolution and color contrast images, and minimizes chromatic aberrations. This benefit is clearly visible with all GPO products supporting this feature. This high-performance process is routinely found in the photographic market and with the highest quality photographic lens manufacturers, but has now transitioned into premium sporting optics.

These binoculars include GPObright lens coating technology. GPObright is a proprietary coating process that maximizes light transmission through each surface of an optical element. As light hits an optical surface, normal uncoated high-performance glass can reflect up to 5% of that light, redirecting this light so it does not transmit through the optical system. However, when these high-performance lenses are vacuum-coated with GPObright lens coatings, up to 99.7% of the available light passes through each optical surface. Furthermore, when every surface of the entire optical system is properly coated, total light transmission can reach up to more than 92%, making the optical image of a GPO binocular “bright,” even in the lowest light conditions.

The 42mm models are compact, lightweight and high-quality options for all your outdoor needs. The 50mm models are characterized by large objective lenses to allow for higher light transmission for the most challenging light conditions.

Completing the package is German Precision Optics Lifetime Warranty that not only comprehensively protects you, but also demonstrates the complete confidence that they have in their instruments.


In this guide we cover

What To Look For In a Birding Binocular?

Whether you’re buying your first pair of birding binoculars, or looking to upgrade an existing pair, shopping for binoculars today can be a bewildering experience. With so many options to consider, and so many models to choose from, where on earth do you start?

Here at Stealth Birding, we know binoculars, and we’ve pooled our knowledge and expertise to bring you this handy binocular buyers guide. We cut through the marketing hype and technical jargon, providing exactly what you need to make an informed decision about the right birding binocular for you.

Focus On Your Ideal Binocular

When shopping for binoculars it’s vital to remember that the relationship between a birder and his or her optics is a very personal one. What’s perfect for me may not suit you at all, and vice versa. There really is no such thing as one universally ideal birding binocular -- it’s all about finding that elusive blend of features and performance that suits your particular needs within your budget.

As you consider the rest of the points in this guide, always bear that in mind, and apply the advice based on what you need from your binocular.

 


Types Of Binocular: Porro Prism Versus Roof Prism

Perhaps the first thing to decide when narrowing down the field of possible binoculars on your shortlist is to select the type you’d like to buy. Binoculars today fall into two main types:

Porro Prism Binoculars

This is the traditional binocular design where the eyepiece lenses are closer together than the objective lenses (the large lenses at the end of each barrel). Prior to the 1960s all binoculars were made this way. In recent times though Porro Prism binoculars are very rairly used by serious birders. This is because they are usually bulkier and ergonomically less comfortable to hold and carry than roof prism binoculars. They are also usually less robust than roof prism binoculars.

Roof Prism Binoculars

This more contemporary, straight-barrelled design results in a more compact, sleek looking binocular that is more robust and ergonomic.

  • Because of the straight barrels, roof prisms are generally more compact and are more comfortable to use and carry for extended periods than porro prisms.
  • Roof prisms tend to be more robust: sealed, nitrogen-purged metal or polycarbonate barrels, often covered in rubber armouring, mean your optical investment is well protected.

Which option you choose is a matter of personal preference, if you’re willing to invest a little more, a high-quality roof prism binocular will generally prove a more versatile all-rounder for birding and wildlife observation in the field.

NB. All of the high-end birding binoculars from leading manufacturers employ roof prism designs.

An example of roof prism binoculars are the Avalon 10x42 PRO HD Binoculars

Avalon 10x42 PRO HD Binoculars

These Binoculars Are Available

In Both Black And White

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Binocular Magnification: Bigger Is Not Always Better

Every binocular has two numbers printed somewhere on the instrument (10x42, 8x32, etc.) -- the first of these numbers (before the x) signifies how much the binocular will magnify the view you’re looking at.

A pair of Bresser Binoculars showing the 10×42 (10x Magnification, 42mm objective lens) printed on the focus wheel.

The higher the magnification, the smaller the field of view

Many first-time binocular buyers make the mistake of assuming that higher magnification is better. After all, the whole point of a binocular is to give you a closer view of your subject, so surely more magnification is a good thing.

Unfortunately, when it comes to optics nothing is ever that simple. While higher magnifications will bring your subject closer, they will also reduce image brightness, decrease focus depth, reduce your field of view and accentuate hand-shake and atmospheric aberration. Magnifying hand-shake can be a real issue, particularly as we get older, so for many people, lower magnifications actually work better.

The sweet-spot for birding and wildlife watching binoculars you can comfortably hand-hold in the field and that can be used in a variety of different habitats, falls between 7x-12x, with 8x and 10x being by far the most popular variants.

Binocular Brightness

Image brightness is one of the most important things to consider when choosing your new birding binoculars. Birds are often active in the early morning or late evening when the light is subdued. Even in the middle of the day, in shady habitats like woodland, light is often in short supply, so you’ll need a binocular that can deliver a bright, clear image in poor light.

The principal factors governing brightness in a binocular are the diameter of the objective lens (the second number after the x printed somewhere on the binocular) and the magnification.

Objective lens diameter: more light in = more light out

Larger objective lenses let more light into the optical system… so binoculars with larger objective lenses have the potential to deliver a brighter image at the eyepiece than those with smaller objectives. There’s a caveat though: as you increase the size of the objective lenses binoculars become steadily bulkier, heavier and more expensive.

In practice, for a binocular you want to carry with you and use in the field, the useful range of objective lens sizes is from 30mm-50mm, with 32mm (mid-size binoculars) and 42mm (full-size binoculars) being the most popular. Smaller “pocket” or “compact” binoculars can be useful in situations where you can’t carry a larger binocular, but are not really suitable as an all-round birding binocular.

Field of View

Binoculars with a wide field of view have a number of advantages for birders. A wider field of view makes it easier to scan large open areas quickly, and makes it much easier to find and follow fast, erratically moving subjects like small birds.

Higher magnification reduces the field of view, but a lot of other factors in the optical design can also influence it. Field of view is measured either as an angle (typically between 6°and 8°) or as a linear measurement of how many metres are visible across the diameter of the field at a range of 1,000 metres (or feet/1,000 yards) and is usually printed somewhere on the binocular.

Optical Quality

The optical design, the quality of optical components and the precision of their manufacture all have a huge impact on the quality of the overall image you see through a pair of binoculars. Here are some of the factors that contribute to the overall quality of the view through your binoculars… and features you should look out for when choosing your next birding binocular.

ED or HD Glass

ED (Extra-low Dispersion) or HD (High Density) elements in the objective lenses of some high-performance binoculars are designed to improve resolution and contrast by reducing or eliminating a phenomenon known as Chromatic Aberration (CA), which can cause a bright colour fringing to appear around high-contrast subjects when you look through binoculars

Images through binoculars with ED/HD elements in their optical system tend to appear crisper, more defined and have truer colour fidelity across the spectrum -- resulting in a more natural, realistic image that’s ideal for birding.

A popular ED binocular are the GPO Passion ED Binoculars

GPO Passion ED Binoculars

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Close Focus

Another aspect of the optical design that it’s important to consider is how close your binoculars can achieve sharp focus. Most contemporary binoculars will focus as close as 2m or closer… but some, particularly at the lower end of the market, may have a specified close-focus distance of 3m or more, and some can focus as close as 1.5m or less. Generally, for birding, 3m isn’t an issue, but if you’re likely to use your binoculars to look at insects (dragonflies and butterflies, for example) or to get a closer look at inaccessible wildflowers on the far side of a ditch or fence, then close-focus could be more important for you.

Lens and Prism Coatings

High performance anti-reflective, high-transmission coatings are critical to the design and performance of contemporary optics. The quality of the optical coatings is one of the key differentiators between mediocre binoculars and truly outstanding ones.

All binoculars on the market today employ some form of coating on the lenses and prisms to improve light transmission and reduce internal reflection. These coatings vary enormously from manufacturer to manufacturer, and at different price-points in the marketplace, but broadly speaking binoculars sold today are either:

  • Coated: some, but not all air-to-glass surfaces in the optical system have a special coating applied to them.
  • Fully-coated: all air-to-glass surfaces in the binocular have a special coating applied to them
  • Multi-coated: some air-to-glass surfaces in the binocular have multiple layers of coating applied to them
  • Fully-multi-coated: all air-to-glass surfaces in the binocular have multiple layers of coating applied to them

For serious birding and wildlife observation NEVER consider buying anything but fully-multi-coated optics.

Anti Reflection, High Transmission Coatings

By applying layers of anti-reflection, high-transmission coatings to optical surfaces, manufacturers optimise the transmission of visible light through the binocular’s optical system, minimising internal reflection, and delivering a brighter, sharper more defined image at the eyepiece. The very best anti-reflection coatings are expensive and technically difficult to apply evenly, adding considerably to the cost of the finished binocular, but dramatically improving its performance.

Phase Corrected Roof Prism Coatings

The way roof prism binoculars work means that the light passing through the optical system is split and then recombined as it passes through the prism system. These separate light paths end up “out of phase” with one another, resulting in less contrast and detail in the recombined image.

To combat this “Phase Shift” good roof prism binoculars will have a special Phase Correction coating applied to the prism surface to correct this phenomenon.

Roof Prism Mirror Coatings

The roof prism design also requires a special reflective mirror coating applied to one of the prism surfaces to reflect light through the prism system to the eyepiece. The higher the light transmission of this mirror coating, the brighter the binocular will appear in low light situations.

The three most commonly applied mirror coatings, in order of increasing brightness (and cost), are:

  • Aluminium mirror coating: typically result in light transmission of 87-93% through the prism.
  • Silver mirror coating: result in light transmission of 95-98% through the prism.
  • Dielectric mirror coating: a special coating technique used in very high specification binoculars to achieve >99% light transmission through the prism.

Protective/Water Repellent Coatings

Premium binoculars often have a special high-tech coating applied to external lens surfaces designed to protect the more fragile coatings underneath. These coatings are very tough, to resist abrasion and scratching, and actively repel water and dirt particles, meaning your lenses need cleaning less often, and are much easier to clean when the need arises.

This feature that’s starting to appear in some mid-market binoculars now -- and where available within your budget is something to consider.

Weatherproofing

Binoculars for birding have to be able to cope with whatever the weather can throw at them. Make sure the binoculars you choose are waterproof and fully sealed. As well as protecting against rain, or accidental immersion, this will also mean your binoculars are impervious to dust and other airborne contaminants.

It’s also important to ensure your binoculars have been purged with an inert gas (usually nitrogen but occasionally argon) at the factory. This drives out the air (and the water vapour it contains), eliminating the risk of internal condensation/fogging as your move between dramatically different temperatures (from a warm car, for example, to a freezing lakeshore, or vice versa).