Binoculars Meaning Everything You Need To Know About Binoculars

I will Start this article with a brief sentence, this sentence will including the binoculars meaning that you already read it, but it still the exact definition you can get for a binocular.

Binoculars is an optical instrument known with different names such as Binocus, Field Glasses, and Spyglass.

Binoculars are built with a series of lenses and prisms. This good construction leads to magnifying objects. So that we can see objects better from a long-distance Using our both eyes. So the main role of binoculars is to view distant objects with both eyes.

Binoculars Structure?

Binoculars Meaning Everything You Need To Know About Binoculars

After finishing with the binoculars meaning, That i hope you understand it. Let’s move to the structure of a binocular.

each binoculars made of two Monocular attached to the same frame. each monocular Has 3 parts, Objectif lens, Dual Prisms, and eye piece. the binoculars has a Central focus Wheel, this piece Helps You adjust the focus of both Left and right eyepiece at the same time for a clear image. 

each individual eyepiece has its Focus wheel helps you to adjust its Focus in case you have different eyes Strengths.

How do Binoculars work?

how binoculars work

Well, I will try to make it simple for understanding. The magnifying process passes through three parts inside the binoculars.

The first thing happens in the objective lens, where the object turns into a magnified upside-down image, but we want the see the image in the right shape. Now we move to the part where the dual prisms do the job can make it straight up by turning it 90 degrees after each prism, then we have the correct magnified object image to be seen.

But to see if we need to situate our eyes with the correct distance after the dual prism system, we use the eyepiece that comes with a ring or a wheel to adjust the clarity of the final image by changing the distance between the eyepiece and dual prism system.

how to choose the best binocular for your needs?

Before choosing a good binocular for our use. First, we need to understand the binoculars meaning and all factors and specifications of a binocular. For this, I decided to share and explain to you the meaning of different binocular specifications. So let’s start.


Binoculars exist in the market with three different sizes, Compact, Mid-size, and full-size. Based on their objective lenses size (the second number in the model name). 

When I mentioned the size. I addressed the diameter size of the objective lens. Due to the different designs and construction, We still can find compact-size binoculars weightier than mid-size and full-size binoculars:

Compact binoculars: objective lens size is less than 30mm.
Mid-size binoculars: objective size is between 30mm and 40mm.
Full-size binoculars: objective size is greater than 40mm.

Binoculars Meaning Everything You Need To Know About Binoculars


by Understanding the binoculars meaning, you will get that the main role of binoculars is to magnify an object image located a long distance from you.

You may find it in other places Defined as magnification or magnification power. (it’s the first number in the model name).
You will find different magnification out there, starting from 4x to 100x or even more.

First, let’s see what binoculars magnification power means. Simply, if our binocular is 8×30 where 8 is the magnification power, that means we will see the object image bigger 8 times than if we use only our eyes.

The greater the magnification power, the larger the image of the object, then the distant object can be seen.

Not only this, if we use 8 power binoculars, we will get a wide field of view, but if the binoculars have 10 power magnification, we will get a closer field of view and a more detailed look.

It looks like more power is always better, but no, it’s not always true, because stability plays an important role here, But how? The high magnification requires steadiness. So if you are in movement, in a boat or maybe a car, or any other moving platform, having high magnification binoculars may be a wrong choice. 

for this reason, it’s better to go with binoculars with a magnification less or equal to 10x.

Field of view:

The binocular magnification also affects the field of view. High magnification will lead to a narrow field of view, and a lower magnification results in an expanded field of view.

If the field of view is small, it would be hard for you to locate your Small-Object all moving objects, also narrower field of view, the images will be a little bit darker.

On the other side, low magnification results in an expanded field of view. So will not be able to get a detailed look for long-distance objects. But you will be able to locate your objects without effort. Also, you will be able to follow moving objects like birds or animals.

Binoculars Meaning Everything You Need To Know About Binoculars

 objective lens diameter:

In a few simple words, the objective lens diameter affects the brightness of the final image. If we take two Binoculars with similar specifications. The one that has a bigger objective lens diameter will result in a lighter picture. 

Also, to get a brighter image, exist another factor that affects the final results, which is the quality of Optics. Good quality Optics lead to Images that are clear and brilliant.

Exit pupil:

The exit pupil on a binocular is the shot of light exits from the eyepiece of the binoculars and hits your eye. With a simple formula, we can determine the exit pupil of any binoculars. It’s the objective lens / the magnification power.

For example:
10×42 binoculars => exit pupil = 4.2 mm
8×42 binoculars => exit pupil = 5.25 mm
8×25 binoculars => exit pupil = 3.125 mm

By Analysing the information obtained, If we increase the magnification power and decrease the objective lens, this will scale down the exit pupil. Small exit pupils mean we will get a dimmer image.

Conversely, if we decrease the magnification power and increase the objective lens diameter will lead to a big exit pupil, which means we will get a Brighter Image, such as the 7×15 binoculars with 2.14 mm in the exit pupil. These kinds of binoculars are great in low light, which means they are great for astronomy.

All this will help you understand the relationship between the magnification power and objective lens size, that’s will make you measure this combination and find what you are looking for.

eye relief:

Eye relief just by seeing the expression is something related to the Comfort of your eyes while using binoculars.

Eye relief is the distance between your eyes and eyepieces of the binoculars at a condition of seeing the world field of view. If you have glasses, you should go for an eye relief of 11 mm and more.

Most binoculars have an adjustable eyepiece, so you can set them to their maximum eye relief value.

Prism type:

There are two types of prism used in binoculars, older ones called (Porro prism). And this type of binoculars, the front lens(objective lens) is not aligned with the eyepiece. While in (roof prism) binoculars, the objective lens he’s aligned with the eyepiece and the prisms.

You can’t recognize the change by seeing the final image in the eyepiece. Both types generate the same image if they have similar specifications.

But having a roof prism system inside binoculars leads to having small and light binoculars, and most, if I don’t say that all Porro prism binoculars are sizeable and heavier.

Waterproof / fog-proof:

When you buy a binocular. I am sure you plan to use it in different places while Traveling or camping, in a kayak, or maybe while it rains, or on the Mountaintop. Where there is different weather. Binoculars are risky to fog-up when you shift from a cold to a warm location. Not only this, but it can also be dangerous if moisture becomes trapped Within.

Binoculars designers Purge the air within the binoculars and replace it with nitrogen, which has no moisture content and hence does not condense. 

This only protects interior lens surfaces from fogging. Not the outer one. Then you have to do your job and protect the outer lens.


We comes to the end of this article, I hope that you find the exact information you were looking for, from the binoculars meaning to the factors and specifications of a binoculars. I I would be happy if this article helps you understand different definitions and information.

If you find this helpful let me know in the comments section.