How do Binoculars Work

Binoculars are also known as binocular telescopes and are being used since hundreds of years for different purposes. They have made it easy to closely view far away objects. Binoculars are defined as handheld magnifying devices, that are made of two similar telescopes attached side by side. Understanding the way binoculars work, can be helpful in case you decide to buy one. Though there are various types of binoculars available, the basic mechanism remains the same for all.

Binocular Parts
To understand how a binocular works, it is first important to understand the various parts of a binocular. It has three important parts - the larger lens known as the objective lens, the smaller lens and a prism that functions as a mirror.

• Lenses: The lenses used in binoculars are convex lenses and they may have two or more lenses. The more number of lenses they have, the greater is their magnification power.
• Eyepiece: The eyepiece performs the function of bringing the image into focus and makes it visible to the eye.
• Prism: The prism, located between the lenses and the eyepieces, performs two functions - it bends the light rays that enter the binoculars, it magnifies the image and then it flips the image. If a prism is not present in the binocular, the image would appear upside down.

How do Binoculars Work?
The functioning of binoculars is based on the principles of light refraction, distance and light reflection. When the binoculars are pointed at an distant object, the light rays from the object falls on the objective lens. The objective lens picks up the light rays and makes a focused image. This image is picked up by the smaller lens and is then magnified. The magnified image is then sent to the prism. It flips the image and sends it to the eyepiece to make a three-dimensional image, available for viewing by the human eye. Some binoculars also permit focusing adjustments through a 'center focus wheel'. It is a movable dial and is located between the eyepieces. The magnification can be adjusted and a sharper image can be viewed. A binocular may also consist of more than one prism to increase their functionality. They may consist of porro prisms or roof prisms. The magnification of the image would depend on the size and placement of the lenses. For example, a binocular rated 7x50 would mean that the image can be magnified up to 7 times and the size of the objective lens is 50 millimeters. The lenses should be aligned appropriately to obtain a clear and bright image. A larger objective lens would be able to collect more light rays and present a brighter image.

Binoculars are usually made of plastic but may be reinforced using metal. They are used for various purposes like birdwatching, safaris, military purposes, hunting, etc. binoculars should be selected according to the purpose for which it would be used. After you have a fair idea of how a binocular works, you would find it much easier to buy one as per your requirement.