Why Are Prisms Used in Binoculars Instead of Mirrors? – Here’s All You Need to Know!

People often wonder why are prisms used in binoculars instead of mirrors

Let’s find out!

Why are Prisms Used In Binoculars Instead of Mirrors?

Binoculars are used to enhance the view. Modern binoculars use prisms instead of mirrors because they’re better at enhancing the view.

Note: If you want t know a complete guide and tutorial about Binoculars click HERE.

What Is A Prism?

Prisms are shapes that refract light. They are used to separate white light into its colors. They work by bending light rays.

A rectangular prism is a 3D shape made up of 4 rectangles. Rectangular prisms are used in many different ways. For example, they can be used to hold things together or to make a building.

Prisms are three-dimensional figures with rectangular flat faces and 2 identical ends.

Prisms vs Mirrors


Galilean Binoculars

Galilean binoculars are commonly used by astronomers because of their ability to magnify distant objects. However, Galilean binoculars do not allow you to see both sides of an object simultaneously.

Prismatic Binoculars

Prismatic binoculars, on the other hand, allow you to see both the front and back of an object simultaneously.

This allows you to get more information about your subject than you could with a mirror.

Note: If you want to know Where Are Swarovski Binoculars Made? Click HERE.


Binoculars are now smaller than before. People use them to see distant objects or to watch sports events. There are many kinds of prisms in binoculars. These prisms make the image clearer.

Reflection and Image Quality


Prism has more TIR than a mirror. Hence, it provides more optical advantages than a mirror.


Mirrors often result in reflection distortion that reduces the image quality. Also, the light absorption rate for a mirror is 95%. Whereas, prism provides the appropriate TIR angels.

In short, a prism produces high magnification and creates bright images of the objects you sight at.



Prisms are used to make images by reflecting light. These are much more reliable than mirrors because they do not require regular maintenance.


Mirrors are used as optical devices to reflect light. However, mirrors are also used to create an image of something else. When the coating wears off, the mirror loses its ability to reflect light. This causes problems when the mirror is used as an optical device.

Hunting binoculars usually use prisms instead of mirrors because prisms can provide better optical quality than mirrors. For example, BAK4 can still produce a better image in bad weather or low light conditions.

Note: If you want to know How to Choose Binoculars? Click HERE.

Magnification and Stability


A prism is an optical device used to separate white light into its component colors. Prisms are also used to create rainbows. Rainbows are formed by sunlight passing through water droplets suspended in the air.


A mirror is used to magnify objects. A prism is used to create an enlarged image.



Mirrors, when used in binoculars, need to be cleaned carefully. Their surface gets damaged easily.


Prism, on the contrary, is thick and sturdy. It doesn’t scratch easily.

Note: If you want to know Where Are Zeiss Binoculars Made? Click HERE.

Why Are Prisms Used in Binoculars Instead of Mirrors?

Why Are Prisms Used in Binoculars Instead of Mirrors?

What Are The Types of Prism Used In Binoculars

Binoculars are used by people to see distant objects. They are usually attached to telescopes or microscopes.

There are many different kinds of binoculars available in the market today. These include

  1. Porro Prism Binoculars
  2. Roof Prism Binoculars
  3. Hybrid Binoculars.

Porro Prism

Porro prisms are triangular-shaped devices used in binoculars. They are named after their inventor, Ignazio Porro who invented them in the year 1960.


The mechanism of the Porro prism is not so complex. However, these kinds are paired together. In binoculars, the lenses stay in the correct position. The image of the object is reversed through the objective lens.

A 90-degree mirror reverses an image by flipping it vertically. This means that the image is upside down when it enters the second prism.

Then the second prism flips the image back over so that it appears right-side up.

Finally, the third prism sends the image into the eye.

If you want to know more information about Binoculars click HERE.

Roof Prism

A roof prism is a type of prism used in binoculars. This prism is made up of two pieces of thick glass. The shape of the prism is similar to a hexagon, but it isn’t exactly.

Porro PrismRoof Prism
Porro prisms come in triangular shapesRoof prisms come in various shapes
Porro prisms are less waterproofRoof prisms are more waterproof


Binoculars are used by people who want to see things up close. Prism is used in binocular lenses because it allows light to pass through them without being distorted. This makes objects appear clearer than if they were viewed through a mirror. A prism works well for viewing distant objects because it spreads out the light coming from far away.

If you have any more questions comment below.


  • John Moses

    John is the Editor in Chief here at The Outdoor Stores. His area of expertise ensures that there is no one better to suggest which rifles are most suitable for your hunting experience. He is also available for you to contact him personally to discuss the types of animals you want to hunt and the terrain you will be hunting on. Feel free to read his posts for expert opinion on Rifles, Scopes, Rangefinders, Bonoculars and Monoculars.

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