How to choose a binocular

Have you ever wanted to buy some binoculars ?
Maybe you've been thinking about it for a while but you don't know what you can use it for, maybe you're just wondering how it works or you're just trying to figure out which binoculars are right for you. This guide will try to answer these and other questions.

Choosing binoculars starts with familiarizing yourself with some technical terms. These terms will identify the field performance of a particular binocular. Once you are familiar with these terms, you will be able to understand the peculiarities of one binocular compared to another and which brands are right for you. There are many brands. Among these we propose some of the best, such as Leica , Kowa , Fujinon , Steiner , Celestron and others.

Leica Noctivid 8x42 Binoculars

Let's take a closer look at these technical terms and what they really mean.

In any binocular, the numbers preceding the "x" or multiplication symbol refer to the magnification of the binocular. The numbers following the "x" or multiplication symbol refer to the aperture of the binocular.

Aperture size simply refers to the diameter of the lens, or its diameter at the front of the binoculars.

Enlargement

The magnification of a binocular refers to how much an object is magnified compared to the naked eye. For example, if you are looking at an object 100 meters away through binoculars with 10x magnification, the object will appear to be only 10 meters away.

Are you wondering how much magnification you need in your binoculars?

Your magnification will need to be appropriate for what you need – think about the needs of your hobby before you think about purchasing binoculars.

1. Will you be using them to see things up close or far away? If you plan on looking into the distance, you will need high-powered binoculars or telescopes (instead of binoculars).
2. How much detail will you need to see? If you need to see a lot of intricate detail, consider high-powered binoculars with a large aperture - just be aware that this will exponentially increase the size and weight of the binoculars.
3. Will you be able to rest your arms on something for support, or will you need something small and compact? If you need something small and compact, you will be better off with binoculars with a smaller aperture size to ensure they are lightweight and a corresponding magnification to ensure you maintain image resolution.

The most popular binoculars are those with lower magnifications (such as 8x binoculars). They have wider fields of view - which makes sense, since you see much more of a scene using lower magnifications. A wide field of view is important when you are trying to follow fast-moving action (e.g., a game in progress; sports), birds in flight, or athletes in a fast-paced sporting event. Therefore, think about how much of the scene (or frame) you want to see at one time - this is very important when deciding what type of binoculars to buy.

Higher magnifications give you more detail, but are harder to hold still: they amplify every little movement based on their magnification factor, and you may find that a tripod is the most convenient way to correct for this.

Lens diameter (aperture)

The size (diameter) of the lens at the front of the binoculars determines the amount of light collected and is called the aperture. The larger the aperture, the more light it can collect, which results in a brighter image. For example, a 10x50 binocular offers better light gathering capabilities than a 10x42 binocular . Although both binoculars have the same magnification, a 10x50 binocular produces relatively brighter images and will give you a superior viewing experience.

However, the larger the aperture size, the bulkier and heavier the binoculars. While 8x20 binoculars offer a less bright and detailed view, they are also smaller and lighter, making them a better choice for those who require more portable binoculars.

Remember: the diameter of the objective lens is directly related to the size of the binoculars: the larger the objective lens, the larger (and often bulkier) the binoculars. So you always have to consider this: if you are looking for portability, you will sacrifice image resolution and vice versa.

Binocular Design - Porro Prisms and Roof Prisms
There are 2 main types of binoculars: porro prism and roof prism. Both use image-building prisms to provide properly oriented images.

Porro prism binoculars

Porro prism binoculars are generally recognized as the "traditional" binoculars. They have staggered prisms and are recognizable by their "V" shaped tubes. Inverted Porro prism binoculars, on the other hand, allow for compact binoculars that fit easily in your hand and are recognized by their "inverted" tube shape.

Kowa 8x30 YFII Porro Prism Binoculars

The technology used in Porro prism binoculars produces large binoculars with lenses that are well separated, but offset from the eyepieces. They generally provide good depth perception, due to the way they are constructed. Porro prism binoculars occasionally need their prisms realigned to bring them into collimation.

When you buy porro prism binoculars you get the best value for your money, but keep in mind that they are not as durable or compact as roof prism binoculars (see below). However, they will generally provide brighter images than roof prism binoculars with the same specifications since roof prism binoculars use silvered surfaces that reduce the transmission of light through their optics.

Roof prism binoculars

Roof prism binoculars are generally more compact than porro prism binoculars and feature a parallel cylindrical style, which allows them to be more compact and durable.

Steiner Observer 8x42 Roof Prism Binoculars

Roof prism binoculars offer greater durability, but tend to cost a little more to get good optical quality in this design.

Field of view

Field of view refers to the size of the viewing window. In essence, this refers to the widest dimension visible through the binoculars. Some binoculars will have unique lenses to provide a larger "field of view" than is typically seen through binoculars of the same magnification.

These binoculars are generally called wide angle binoculars. Wide angle binoculars are preferred if you are looking to observe closely in the woods, or if you are interested in picking up things that move quickly through the viewing area (think bird watching).
Note: The field of view decreases as the magnification increases and vice versa. Choose to buy binoculars with lower magnifications if a wide field of view is important to your activity or buy wide angle binoculars instead. Also, large objective lenses (aperture) provide a wider field of view. Porro prism binoculars also offer wider fields of view than roof prism binoculars, given the same specifications.

Pupillary extraction

Many people wonder what they should do if they wear glasses while using binoculars. Most binoculars are designed to allow comfortable viewing even with glasses, and thus provide greater relief to the eyes.

Eye relief simply refers to the distance that images are projected from the lens to their focal point and ranges from 5mm to 23mm. If you are looking for binoculars to use with sunglasses or glasses, try to look for binoculars that offer at least 15mm of eye relief. Note: Without adequate eye relief, you will not be able to see the entire field of view with glasses.

When using binoculars, make sure you understand how to use the eyepieces: all binoculars allow you to control them. There is a rubber eyepiece that can be folded down or, more commonly, a newer type that twists or slides up and down over the binocular eyepiece.

If you wear glasses, you will definitely want to purchase binoculars with sufficient eye relief. You will want the binocular eyepieces to be rolled down (i.e. positioned down, close to the binocular) when in use. This ensures that you see the maximum field of view.

Conversely, if you don’t wear glasses, try leaving them fully extended (positioned away from the binoculars), allowing the eyepieces to lightly touch your face. This helps block peripheral light.

Diopter adjustment

The best quality binoculars allow you to adjust the focus on one eyepiece (usually the right eye) of the binocular using a diopter adjustment.

The purpose of a diopter adjuster is to compensate for differences in your eyes, so you can see the clearest image possible through the binoculars.

To make the diopter adjustment, choose an object to focus on in the distance. Try to choose something distinctive that is past the close focus distance of your binoculars, but not too far away.

Now

1. Focus on the object using the center or individual focus of your binocular (with the correct eyepiece diopter locked/eye closed).
2. Once the image is in focus as sharply as possible, close that eyepiece / close your eye on that side.
3. Now, open the other eye (on the correct diopter side) and without moving the center or the individual focus ring, try to improve the sharpness of the image by moving the diopter adjustment.
4. Now that you have found the setting that gives you the sharpest image, write it down and leave it there - that's it! From here on, use only the center focus to adjust both eyes while viewing.

Note: You must set the diopter adjustment when you first use the binoculars and make a note of the settings. Check the diopter setting on your binoculars to make sure it has not changed, and again after sharing the binoculars with someone else.

Cleaning the binoculars

So now that you have a pair of binoculars of your own, you're probably wondering how to clean binoculars.

First of all, always use common sense in the care and maintenance of your binoculars. Try to remove any visible dust and dirt before brushing or wiping anything on the glass lenses of your binoculars.

Otherwise, use a lens cleaning tool such as a lens pen or lens cleaning tool to gently remove any remaining marks or smudges from the binocular lenses. If the marks are stubborn, such as dried water spots, remove them by misting the lenses with your breath and drying them with microfiber cloths.

Note: DO NOT use shirt tails or tissues to clean binocular lenses, as they contain fibers that can damage or scratch the coatings on the lenses. After purchasing the perfect binoculars, the last thing you want to do is permanently scratch those beautiful lenses!

Do your best to keep your binocular lenses as clean as possible, free of dirt and oil. Occasional cleaning with vinyl and rubber preservatives will prolong the life of your rubber eyepieces.

Other features

Image stabilization

Stabilized binoculars are designed to counteract the natural instability of the hand. This feature uses gyroscopes and liquid-filled prisms that automatically correct jitters and tremors.

Fujinon TS 12x28 Stabilized Binoculars

As the magnification increases, so does the image instability, no matter how steady the user's hand is. Therefore, image stabilization is especially important for high-magnification binoculars. Image stabilization is also useful for use in unstable situations, such as when navigating, or for long-term observations where muscle fatigue can amplify the instability. So, with image stabilizers, you can enjoy a clearer view for a longer period of time.

Focus: individual vs central

Center focus binoculars allow you to adjust both eyepieces at the same time. This is useful for applications that require quick and frequent adjustments. Center focus binoculars are a popular choice for hunting, bird watching, and general wildlife observation.

Individual focus binoculars require each eyepiece to be adjusted separately each time you change focus. These binoculars are suitable for applications that do not require frequent adjustments, such as marine, surveillance and astronomy.

Water resistance and nautical binoculars

Waterproof binoculars feature tight seals and exterior coatings that provide protection from precipitation, dew, and accidental splashes and spills. This is usually sufficient protection for most binocular applications.

Fujinon 7x50 FMTRC-SX-2 Marine Binoculars with Compass

Truly waterproof binoculars have features that allow them to function even when fully submerged in water (usually up to 5 meters deep). This type of binoculars is a wise choice for boating and/or marine use.

Zoom Binoculars

Zoom binoculars are sometimes called "variable zoom binoculars" because they allow you to "zoom in" and "zoom out" just like you would with a standard camera. The main advantage of zoom (variable) binoculars is that they are capable of multiple levels of magnification, but keep in mind that the lens size does not change. This means that as you increase the magnification, you reduce the diameter of the exit pupil, which results in a darker image. With zoom binoculars, the magnifying power is there when you need it, but the resulting high-magnification images will be dark and unstable.

Note: If most of your viewing will be at low magnification, but you want the option for occasional magnified viewing, zoom binoculars are a practical choice. However, if you plan to use high magnification levels frequently, you may want to consider higher powered binoculars with objective lenses of an appropriate size for comfortable viewing.

One important thing you need to know about binoculars is that they are actually two independent telescopes connected to each other.

It sounds pretty primitive, and it still is - despite many improvements with technology. Zoom binoculars must maintain some sort of synchronization between the two scopes, consisting of a movable lens element inside each eyepiece. This is usually accomplished by a flexible metal band - known as a "zoom link band" - that passes through the eyepiece arms to connect the zoom mechanisms on either side.

Due to the sheer number of moving parts, it is impossible or very, very difficult to get both scopes aligned properly. Therefore, collimation problems often occur. Each image will shift slightly as the lens elements move, and while this is not noticeable in a monocular, binoculars end up never being in “perfect” alignment.

In general, unless a zoom feature is very important to you, we recommend purchasing binoculars with a fixed magnification instead. Fixed magnification binoculars will be less versatile than variable zoom binoculars, but they will be more robust and will provide a far superior viewing experience.