How To Read Binocular Specs – Guide to figure out it

Binocular specs are not the easiest thing to read or understand. There are many numbers, letters, and symbols that you need to understand. This post will help you learn how to decode binocular specs so that you know what everything means about your binoculars.

What does the focal range mean? What does a° stand for? How do you find the eye relief of your glasses? The answer is all in here. It’s better to read the entire post, so that you get the entire picture. Some numbers can be big (or small) and confusing, but if you understand the gist of things you’ll know what they mean.

How do your binocular specs work?

Converging lenses are used to magnify whatever you look at through them. This is how binoculars function. It is like a camera lens that narrows down light rays and creates an image on film or digital chip that we can see.

The lenses are usually made of high quality optical glass that’s suitable for magnifying things. An objective lens collects light and focuses it at a certain point. The second lens, called the ocular (or eyepiece) is the one that shows you the image of whatever you are looking at.

A binocular is a compact device so there’s no way to move your head around to look at things separately with each eye. Instead, they have a mechanism inside them (usually located between the two lenses) called a prism. It’s a glass block that is placed in front of the ocular lenses.

A prism bends each light ray individually and focuses it on your retina so you can see a clear image. The prism also helps to focus the image into the eye so you can see it clearly. This is why most binoculars have two different lenses because they need both to be able to function.
If there’s only one objective lens, then the eye relief would be too short. If there are only two, then it would be too long. So there needs to be a balance of both. Some binoculars can have only one lens, but for most it’s two.

How do you use your binoculars?

Binoculars are very important devices that are used for a variety of purposes. You can use them to see what’s on the other side of the lake or in the woods or even at a concert! They’re great to have when you’re camping, hunting and even traveling.

Usually the lens comes in two parts. The objective one and the ocular one. The lens is held by a frame that can attach to your belt or even your pocket. You can use your arms to hold them if you want, but the most common way is to hold them up to your eyes and get a better view of what you are looking at.

The arms on binoculars come in many different sizes, shapes, and colors. Some are more comfortable to hold than others, but most of them can be adjusted to fit your hand better. Just make sure that you adjust them to the right size before you decide.

The lens can be moved in and out of the frame so you can get them closer or farther from your eyes. This is called eye-relief and is a very important aspect of binoculars. The higher the number, the more eye-relief a pair has and the easier it will be for you to see things clearly through them.

Eye-relief is what separates quality binoculars from cheap ones, believe it or not. Most binoculars are fine with 6′-10′ of eye-relief. The more you have on a pair of glasses, the better it will be for you to see things.

If you wear glasses and want to use them for looking at things, then you should probably get 10′ or higher. If you don’t like wearing glasses, then 6′ will most likely be fine.

How do you find the specs of your binoculars?

The easiest way to find out what your binoculars are is from the tag on them. Most companies print their specs on the side or back so that you can see them. If not, then there should be a description somewhere on the item about what it does and how to use it.

If neither of those things works for you, then the Internet is one of the best places to go to find out more about your binoculars. You can search for the model and brand, and there should be a website or FAQ that explains what certain numbers mean. This post is another good way to find out more as well!

How do you read binocular specs?

There are plenty of numbers on every binocular so you should know what they all mean. This can be difficult, but if you read the whole article, you’ll know what everything means by the end.

Here are a few examples of the types of numbers that you can find on your binoculars.


This number is very common and refers to how much closer or farther away something can be viewed through your binoculars. Most binoculars are around 10x magnification, which means they let you see things close to 100 feet away clearly. This is similar to a telescope.


The lenses in binoculars can be adjusted so that you can focus on objects closer or farther away. Most binoculars have a focus of around 1.5x, which means they use a cylindrical lens to magnify the image of something differently. This is similar to a microscope or telescope.


This is one of the numbers you will find on your binoculars and most often corresponds to how bright the image appears through it. There are different levels of power and some are better than others. The higher the number the brighter it is, so this should always be taken into account when choosing a pair!

Peripheral illumination

This is the light that shines around your field of view, which most often happens because of reflections off the ocular lenses. This can be problematic if you look at bright lights or something, so it’s important that yours match up with your environment.

Exit pupil

This is a measurement of how much light passes through the lens into the eyes. It’s important that you adjust your binoculars to match this number, so this number should always be taken into account.

Field of view

Most binoculars operate on a system known as the “field of view” (FOV). FOV is the area of your field of vision that can be seen through the eyepieces. A binocular’s FOV is often described in terms of a circular area with a diameter equal to half the width of one eyepiece. For example, if you have 20x magnification, the FOV would be 5 inches.

To help you visualize this, you can use a simple formula that relates magnification to FOV. For every 1x of magnification, the FOV is equal to half the width of the eyepiece. Therefore, if you have 15x magnification, the FOV will be half the width of one of your eyepieces, or 6 inches. Again, if you have 20x magnification, then the FOV will be half of 10 inches (5 inches).

For example, if you have binoculars with 10x magnification, then the FOV will be 1/2 the width of one eyepiece. If you have 15x binoculars, then the FOV will be 1/2 of 1.5 inches (3/4 inch).

The higher the magnification, the smaller this area can be. At 8x magnification, for example, your FOV will measure 10 inches in diameter . At 20x, the FOV will measure 2 inches in diameter.

A basic rule of thumb is that if you have a pair of binoculars with a wider field of view, they’re easier to use, but harder to hand-hold. This is because your eye doesn’t have that much space for movement, which can make it difficult to follow objects up close. On the other hand, narrow field binoculars tend to be easy to hold and can often provide higher magnification with less effort.

This is where the exit pupil comes into play. The exit pupil is found by dividing your binocular’s objective lens by your magnification. In other words, it’s the amount of light that reaches your eye after being transmitted through the lens and pupil of your eye.

It’s also worth noting that low-light performance will be affected by a number of factors, including a binocular’s diameter, glass quality and coatings, along with how much ambient light around you. Binoculars designed for low light use, such as night vision, are typically designed with a wider exit pupil to ensure a high level of contrast.

According to the International Organization for Standardization , exit pupil diameter is the standardized measurement used when referring to binocular lenses and should be listed in millimeters. For example, if a binocular’s objective lens measures 50 millimeters (mm) in diameter and you get 25x magnification, the FOV will measure 325 mm.


This means that you can see straight through the lens and all the way to the inside of your eye. This can be helpful when looking at things, but it’s not necessary for all use cases.


These coatings on the lenses help you see better and are more common than they used to be. They’re usually found on higher-end binoculars so it’s important that you take them into consideration when choosing your pair!

Achromatic Glass objectives

This means that your objective lenses are made with two different types of glass and have low dispersion. The less this number means, the better it is because it makes the image brighter and clearer.

Chromatic aberration

This number shows how much there is of something called chromatic aberration, which is when different wavelengths interfere with each other. This can cause the image to appear blurry or distorted so it’s important that this number is low.

Eyeglass Compatible

This is a measurement of how your binoculars will look to you if you wear glasses. If this number is higher, then your glasses will not interfere with the image. Focal length: This is how long the distance between two of your lenses are, which should be labeled on the binoculars. It’s measured in millimeters and can range from 50mm to 200mm+.

High magnification

Binoculars with a high magnification are very helpful if you want to see something far away but don’t have much time to do it in. If you’re interested in sports or wildlife, then getting a high magnification is important. Not to be confused with power!

Minimum Focus Distance

This measurement shows how far away your binoculars can see something clearly since it’s the closest point at which you can get an image. If your minimum focus distance is 200m, then this means you can see things that close to you clearly, but anything closer than that will not be as clear.

Porro Prism

These are the types of prisms that your binoculars have. They can be cheaper, but they’re not as clear or crisp as other kinds.

Roof Prism

This is the best kind of prism that you can get on your binoculars and help them give you a clearer image. They’re more expensive, but definitely worth it if you want to spend money on your binoculars. Size: This tells you how big your binoculars are and what kind of case to buy for them.

Tripod Adaptable

This is important for nature and sports lovers, but not so much for others. If you want to take your binoculars on trips and hikes without a tripod, then this is something that might interest you.


If you plan on using your binoculars in wet conditions, then this can be important. If not, it’s not that necessary.

UV Locking

If you’re going to be taking your binoculars into the sun, then this might be useful for you. It means that your lenses can block the harmful UV rays from the sun. More about UV and sun glasses here.


This is the maximum magnification your binoculars can achieve which will obviously be higher than your minimum focus distance. These are usually not the best pair for sports because of the lack of precision.


This is a form of binoculars that aren’t as regular in shape as regular binoculars and often have an eyepiece sticking out of one end. They can be more compact and easier to carry around than regular binoculars.

Binocular specifications are commonly listed as weight and magnification. In fact, you’ll find separate specifications for each. These measurements are useful when comparing different models, although for most people the differences won’t be very large. For example, if you have binoculars with 20x magnification and 17-ounce glass, you’ll have a FOV of 6 inches when using both eyepieces. And if you have binoculars with 20x magnification and 8-ounce glass, you’ll get a FOV of about 4 inches.

The following is a sample list of the most common specs for binoculars that can be found on the market:
+/- 2.5% @ 28° F (±3° C)
Diopter Adjustment Range: +/- 7 Dpts (±1 Dpt = 1/6400 mm) for differences between + and -2.5 Dpts

Dioptric Correction Range: ± 5 Dpts (±1 Dpt = 1/6400 mm) for differences between + and -5 Dpts.

In addition to these, you’ll often find specs related to Exit Pupil and FOV. The former is located in the “Objective Lens” section of the specs, which refers to the largest lens on the binoculars. You can easily find this number by dividing the diameter of the lens by your magnification level.

The FOV is located in the “Field of View” section of the specs. You can find this value by dividing the diameter, or exit pupil, by your magnification. For example, if you have 15x magnification and a 5.3mm exit pupil, your FOV will be 3 inches.

As mentioned above, you’ll rarely see differences between specs that are more than 2-3% unless they’re very expensive binoculars.


Hopefully this guide has provided you with some useful information. If you want to learn more about binoculars, make sure to check out our product reviews on the website. It’s likely there will be something that fits your needs!

– Check this hunting binoculars guide know more how it will be.

– Read more on bird watching & hiking binoculars less than $100.

– Read how a marine image stabilized binocular.

Matthew Koch

Hi, I'm Matthew, a passionate blogger and traveler. I'm also a hard-core hiker. Hiking with friends and visiting new places is what I live for. Currently, I'm working at Gear Odds as CEO & Columnist. I would like to provide my best outdoor experience possible.

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