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Different Parts of a Binocular | Explained in Simple Terms

parts of a binocular
Written by Dan Goldsmith
Last Update: August 11, 2023

Binoculars are a pair of telescopes installed alongside and brought together so viewers can pair through for a magnified view of objects from a distance.

They are usually compatible, and you can hold them with both hands.

However, they vary in size and can be as small as opera glasses to as large as mounted military models.

Have you ever wondered what’s inside those handy tools? What are the different parts of a binocular? How do they work seemingly to provide sharp images?

That’s what we’re about to explore today. Let’s get started!

Binoculars are different from monoculars and would give the user three-dimensional images way if the two views, giving the user two merged perspectives, and creating an impression of depth.

You can use a pair of binoculars in different ways.

They are used popularly by the military both on land and sea and are a tool of choice by hunting enthusiasts and birdwatchers.

Anatomy of a Pair of Binoculars

The binocular parts can be classified into two categories: mechanical parts and optical parts. The optical parts, as the name implies, is the part we see-through.

Simultaneously, the mechanical parts of the binocular are the extra functions to optimize the user experience.

This article will try to get you familiarized with the different parts of a pair of binoculars.

Optical Parts of a Binocular

Optical parts of a binocular

  • Objective Lenses

They reflect and magnify the light to the different parts of your binoculars. They will give an accurate and clear image.

The size of the objective lens is a factor in the amount of light the binoculars can get from the focused object.

The objective lenses vary in size and shape. However, how light or heavy the binocular is depends on the affected parts that come with the objective lenses.

Contemporarily, special coatings are added so that the lenses can reflect more light.

The coatings increase the optical performance of your binoculars. We recommend holding the objective lenses with care as they are the most fragile part of the binoculars.

A binocular pair with a broken objective lens is considered damaged.

  • Eyepiece Lenses

This part of the binocular magnifies the light field on each lens.

The eyepiece is the part closest to the eyes when you look through the binoculars, and they are noticeably smaller than the objective lenses.

The function of the objective lens is to gather light. When it does this, all of the magnified images are focused on the binoculars.

The focal length of eyepieces might vary; they all play an essential part in magnifying an image. There are various lenses contained in the eyepiece.

It is through these lenses that the image is focused once you move the eyepiece lens close to eh objective lens.

  • Prisms

We know that the objective lens collects light and forms an image.

However, the image is not correct and has been distorted.

In order to correct this distorted image into an actual practical image, the prism is between the eyepiece and the objective lenses.

Those crystals aid the binoculars in decreasing them to a smaller size, for it to be compatible and comfortable on the hand.

There are mainly two types of prisms that a binocular has. They include a roof prism and a Porro prism.

  • Porro Prisms

Ignazio Porro invented the Porro prisms in the mid-1800s in Italy.

Porro prisms are multicoated, making the lens’s surface reflective, and maximizing the amount of light in the binocular, thus having a sharp image.

A Porro prism’s optical path has a bent Z-like structure, increasing its sight, and also the size of the binocular.

  • Roof Prism

The roof prism corrects the binocular image: containing various surfaces of which one of the surfaces prevents an internal reflection of the image, making the binocular lose some of the light and a duller image.

The roof prisms are coated to get sharper images, without the loss of light.

Mechanical Parts of a Binocular

Mechanical Parts Parts of a Binocular

  • Diopter Adjustment

The diopter adjustments are rings that are individually placed after the eyepiece lens.

One can find the diopter adjustments either on the right or left objective lens or eyepiece lens.

Furthermore, with the adjustments, one can set the eyepiece lens individually. They help those who wear glasses to focus on images without stressing their eyes.

  • Focus wheel

The focus wheels are usually placed close to the eyepiece lens and can be found close to the objective lens. It is through the focus wheel that the image is focused.

When the image is focused, it comes to the center, and then it is called a center focus.

However, when the image is focused on aside, they are called left or right binoculars depending on which parts.

The focus wheel moves the eyepiece lens creating clarity in the image. They help people who use glasses to focus on images without removing their glasses.

  • Chassis

The chassis holds everything in the binoculars in place.

They are made of different materials, which is why they vary in durability, strength, and weight.

  • Barrel-Bridge with Hinge

We know that binoculars are two individual telescopes paired together; however, for an accurate image, they have to point in the same direction so that the observer can have one view from two different perspectives.

The barrel bridge keeps the binoculars aligned parallel against each other for a parallel optical axis.

The hinges help the user to adjust the eyepieces directly to the user’s individual eye.

  • Barrel or Tube

This holds all of the optical parts together. They cover and protect all optical parts, holding them in a stable position, such that they cannot shift easily after a drop.

Some binoculars often come with a ring to keep water out of the binoculars, while others can even feel the binoculars with glasses to also get the air out.


With the information you have now, you can get your binoculars since you’re aware of all the parts.


Q. 1: What Is a Good Binocular Magnification?

Ans: The popular recommendation is to look for a binocular with a 7x to the power of 10x. A good binocular magnification, all depends on what you want to use the binoculars for.

A theatergoer only has to choose something in the range of 3-5x while hunting binoculars’ magnification range should be 10×50.

Q. 2: What Are the Two Different Types of Binoculars?

Ans: The two main types of binoculars are the roof prism and the Porro prism. The Porro prisms create a sharper image than the roof prism.

About the author

Dan Goldsmith

Hi, this is Dan. We all know firearms are dangerous, but only when one doesn’t know how to use and care for them. I have 30+ years of experience with different types of guns and for the last 10 years, I have taught numerous people how to hold and shoot a gun while staying safe and keeping the surroundings unharmed.

My neighbors are some of my biggest admirers who enjoy talking to me about their guns, firearms safety and maintenance.

Whenever I am able to catch a moment of free time, you will find me enjoying my family or heading to the range on my motorcycle. I have enjoyed shooting sports ever since my dad introduced them to me as a child.

I like to think of myself as an outdoorsman who lives his life to the fullest. I hope you will benefit from my efforts to create valuable resources on this website. Happy reading!

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