How to choose bird-watching binoculars?

Have you just started birding and are looking for the best binoculars? 

Choosing the right binoculars can be confusing, especially if you’ve never purchased them before. Binoculars are used for such a wide range of purposes, from astronomy to wildlife observation. It’s important to have a pair that’s perfect for the activity you plan to use. We have developed this guide specifically to explain in detail what to consider when looking for bird-watching binoculars. 

You’ll notice that all binoculars have a set of two numbers, which can help you determine if they’re right for your needs. The first number indicates magnification (sometimes called power or zoom). The second number refers to the size of the objective lens. For example, 8×32 binoculars mean they have 32mm lenses with 8x magnification. 

apexel bird-watching binoculars

1. What are the requirements for bird-watching binoculars?

A pair of binoculars is a must for bird-watchers. They not only help us observe birds in more detail but also bring beauty and delight to our hearts! Binoculars are of moderate size and weight, suitable for carrying at any time, comfortable to observe, large field of vision, ideal for observing forest birds (forest birds are not far away from the observer, moving fast angular speed), and very easy to operate! Requirements for bird-watching binoculars are as follows:

(1) The best magnification for bird watching

The prospect of very large magnifications may be attractive, but there are a number of reasons why choosing the most powerful binoculars may not be the best choice for bird-watching. For starters, using binoculars with very high magnification (for example, 16 x or more) will require a tripod to help you get a stable image, which may be inconvenient. In addition, more powerful binoculars don’t have as wide a field of view, making it harder to focus on moving objects.

We prefer 8x magnification because it offers a wider field of view, comfort and image stability. They also tend to provide greater eye relief, making them more suitable for eyewear. Handheld devices can still use a higher 10x magnification, and if you don’t use binoculars or mind the extra weight, this might be a good compromise, better suited for hiding or viewing estuaries, reservoirs, or other large, expansive areas. We don’t recommend buying cheap, high-magnification binoculars because they performed significantly worse in our image quality, sharpness, and durability tests.

(2) Caliber

Caliber refers to the diameter of the objective lens, generally between 20 and 50 mm. Small diameter, small size, lightweight, good portability, but low imaging brightness poor observation comfort. The large diameter is a large volume, heavyweight, poor portability, but high imaging brightness and good observation comfort. The common 20 and 25 mm calibers are mainly portable and suitable for use as backup mirrors. The 30 and 32 mm diameters are a compromise between effect and portability, while the 42 and 50 mm diameters highlight the observation effect and are suitable for the main mirror!

(3) Exit pupil diameter and specification

Exit pupil diameter is closely related to imaging brightness and observation comfort. The calculation method of exit pupil diameter is objective lens diameter ÷ multiple. The 2.5mm exit pupil diameter is suitable for bird watching in a well-lit environment, such as 8×20/10×25.

The advantage of these specifications is that they are small in size, light in weight, and easy to carry, but the observation comfort is poor. The exit pupil diameter of about 4mm can relax the requirements for light, such as 8×30/8×32/10×42, which can meet the requirements of bird watching on most occasions. The exit pupil diameter above 5 mm is basically an all-day weather type, especially suitable for observing birds at dusk and dawn, such as 8×42/10×50, brightness clarity and comfort are very high.

(4) Prism

A prism must be added to the binoculars to obtain positive images. Common prisms are divided into roof prisms and Porro prisms. Generally speaking, binoculars with roof prisms are more suitable for bird watching. Their appearance is characterized by two straight tubes in the barrel and a small center distance between the objective lens, which is suitable for observing close targets.

It is also easy to be made into a nitrogen-filled waterproof structure, which is more suitable for the harsh outdoor environment. Small size, lightweight, portability! However, the use of roof prism to obtain excellent observation effect, need to use high-precision prism and complex coating, high cost leads to high price. The binoculars using the Porro prism are curved in shape, with a large center distance between the objective lens and the nearest observation distance.

It is not easy to realize nitrogen-filled waterproof structure (high sealing can be obtained by using left and right independent focusing, but this focusing method is not suitable for bird watching), and it is large in size and heavy in weight. But the advantage is the low technical content of optics, with a relatively low price can get a good effect. There are also anti-Porro prism binoculars, lighter, but small aperture, not suitable for the main mirror.

apexel binocular

(5) Closest observation distance

Bird-watchers usually want a smaller closest observation distance so that they can observe birds hidden in bushes or grass. The roof prism binoculars, its recent observation distance can do is small, can often close to 2 meters high (such as a forest with 8 x32 recent observation distance of 1.2 meters), using the Porro prism binoculars recent observation distance and perhaps even less than 1 meter.

(6) Focusing type

When observing forest birds, the distance between birds and people is sometimes far and sometimes near. Only central focusing can adapt to the rapid change in the distance of the object being observed. Some centrally focused Porro prism binoculars use o-rings to seal the active eyepiece in order to achieve waterproof construction, resulting in high focus damping and sore fingers during prolonged operation. As for the Porro prism binaries focusing left and right (such as military telescopes), the focusing speed is very slow and is not suitable for observing fast-moving birds.

(7) Waterproof and shockproof

Bird-watching activities are often carried out outdoors, and the observation environment is changeable. It is best to choose anti-immersion binoculars, so as to keep the mirror inside sealed and dry, without fog and mildew, and improve the service life of the telescope. For the surface coated binoculars, not only the shockproof effect is good, ensures the stability of the optical axis, holds up more comfortably.

(8) Coating

For Porro prism, only an antireflection film is enough. For roof prism, reflection film is necessary. In order to obtain good results, in addition to the antireflection film, phase film needs to be plated. So in the selection of binoculars, it is necessary to understand the binoculars coating situation.

(9) Eye mask and exit pupils’ distance

Bird-watching is different from watching the scenery on the balcony for nearsighted/aging/astigmatism birds. When watching the scenery on the balcony, the glasses can be taken off slowly to adjust the focus, while bird-watching usually uses binoculars to observe the birds after wearing glasses first.

Therefore, a soft eye mask that can be folded or rotated is required, otherwise, the full field of vision cannot be observed. A hard eye patch can be very uncomfortable. Also, do not choose an exit pupil distance that is too short. Exit pupil distances of less than 15mm will force the observer to keep their eyes tightly pressed against the eyepiece, otherwise, they will not see the full field of view.

2. What are the requirements for bird-watching monoculars?

Binoculars have many advantages, but if you want to see more details or water birds, you need high-powered monoculars for bird-watching. Requirements for bird-watching monoculars are as follows:

apexel bird-watching binoculars

(1) Optical type

Short focal length refraction telescope must be selected, and waterproof structure. Its small size, lightweight, sharp imaging, good durability! (Reflecting and folding types are generally used in astronomical telescopes, which are complex to operate, very heavy, inverted, can be viewed from the side of the mirror, and are not waterproof, so they are not suitable for bird-watching or scenery viewing.)

(2) Objective aperture

The aperture between 50-100 mm is more suitable, and the aperture is closely related to the volume, weight, and multiple of the telescope. Too small an aperture would result in a telescope with too low a useful multiple for fine observations, and too large an aperture would mean too much size and weight, making it difficult for birders to climb mountains and wade in the water with a large object on their back. At present, the caliber of the mainstream bird-watching mirror is about 80 mm, and the caliber of about 65 mm will be relatively light, and the supporting tripod and cloud platform can also be light.

(3) Objective material

The objective lenses of high-end bird-watching monoculars will be made of ED glass, and the objective lenses of top-of-the-range bird-watching monoculars will be made of fluorite. ED glass and fluorite are expensive and have a low processing rate, so they are also expensive. Compared with ordinary optical glass, ED glass can effectively reduce chromatic aberration and improve imaging clarity, especially in a high-power state. Fluorite is better than ED glass.

(4) Eyepiece

Bird-watching monoculars often come with a zoom eyepiece (the multiple is generally 20-60 times), which is simple to operate and convenient to use. A good zoom eyepiece will have a larger field of vision, smaller distortion, and longer exit pupil distance. Some monoculars provide fixed focus eyepieces with different focal lengths as an optional accessory, which can obtain better observation results, but the operation of switching multiple is cumbersome. And unlike astronomical telescopes, the eyepieces for bird-watching monoculars are almost universal.

(5) Antireflection film

Antireflection films can also improve the brightness and contrast of the image, reduce flares and glare, and make the image more bright and clear. Good antireflection films tend to be dark green reflective. Some bird-watching monoculars, for cost reasons, have no coating on the inner lens (the coating on the outer lens is easy to identify, so no corners are cut), or just a single blue anti-reflection film. It is recommended to choose FMC coated single barrel birdwatching mirror first!

(6) Mirror body material

Top models will use aluminum-magnesium alloy to manufacture the mirror body, strong and lightweight. Common airframes are made of aluminum alloy, which is cheap, strong, and only slightly denser than aluminum-magnesium alloys. Low-end bird-watching monoculars, on the other hand, tend to be made of plastic, which is very cheap but prone to aging and deformation. The stable structure is the guarantee of optics, but also the guarantee of durability. It is recommended to choose metal monoculars for bird watching!

(7) Nitrogen-filled waterproof

This is a very popular technology. Dry and clean nitrogen is injected into the sealed internal cavity of the telescope to prevent the invasion of fog, mildew, dust, and water inside the telescope. It can adapt to the changing climate of the field environment and greatly improve the service life of the telescope.

apexel bird-watching binoculars

(8) Oblique tube VS straight tube

It is generally recommended to choose oblique tube as bird-watching monocular, the most comfortable observation angle. If a straight tube is selected, the tripod must be raised to reach the eye, which reduces stability and makes the viewing angle uncomfortable. But a straight tube is a good way to shoot birds with a camera or phone because the line of sight is aligned with the monocular.

(9) Tripod and cradle

Many novices ignore the importance of tripod and cradle, and often do not want to spend money on the tripod and cradle. It is very important to choose a light and firm tripod. Light can reduce the burden of trekking in the field, and firms can improve the stability of observation. A carbon tripod is the best choice. Supporting the head does not choose the ball table, to choose the handle to control the left and right and pitching camera 3D head. Its operation is the simplest. conditions permit it to choose the hydraulic head, the most smooth operation.

3. The specific choice and buy

Bird-watching monoculars can be considered in Apexel, very cost-effective. Ask birders around for their opinions before you actually buy them. Or go to the corresponding monocular forum, post-bar, QQ group consultation, will find the right bird-watching monocular!


What strength binoculars do I need for bird watching?

Most birders prefer binoculars that are between 7x and 10x. In the past, 8x was the standard median power between 7x and 10x. Today, some manufacturers offer 8.5x and even 9x as a compromise between the power of the 10x and the steadiness of the 8x.

Are 10×50 binoculars good for bird watching?

10×50 binoculars are a bit too heavy for general bird watching and have some other drawbacks. The close focus distance is generally not close to these binoculars. They may not have good eye relief, either.

How do you pick wildlife binoculars?

As with many things in life, the key is finding a happy medium, so aim to get binoculars that will suit the majority of your wildlife viewing. Binoculars with a magnification of either 8 or 10, and a lens size of 40 or 42, are generally considered to be the most suitable for viewing wildlife.

What is the difference between 10X42 and 10×50 binoculars?

The 10X50 objective is larger, with better brightness and focus edges. A 10X42 center focus is probably better.

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