A History of Binoculars

With the help of binoculars, you can view distant objects near you even if they are located very far away. Most of the binoculars are held by two hands and they are large in size but there are some binoculars that are smaller in size and can be held by one hand only. There are several different types of binoculars. Some of them are listed below:

Galilean binoculars

This type of binocular has been in use since 17^th century because of its advantage of allowing an individual to mount it side by side for a proper binocular vision. A Galilean binocular uses a concave lens and a convex objective. The only problem with a Galilean binocular is its narrow vision and low magnifying power. Even today, many people use Galilean binoculars in theatres because of their low price.

Prism binoculars

Prism binoculars provide an enhanced image along with better magnification when compared to Galilean binoculars. The major disadvantage of prism binoculars is that the image is presented in an inverted manner, i.e. a reverse position of the image is shown. This disadvantage could be rectified by using various correcting methods.

Porro Prism binoculars

Porro Prism binoculars are named after an optician Ignazio Porro from Italy. He patented his invention in 1854 and later on it was modified by Carl Zeiss in 1890. These binoculars use a double prism configuration to erect the image. The major advantage is that with a double prism configuration, a wider view is presented and the user can concentrate on objects more closely. Also, a better view is presented that gives a better sensation of depth.

Roof Prism Binoculars

Roof prism binoculars appeared in the beginning of 1970 and these were named after Albert Koenig and Ernst Karl Abbe. Later on these were patented by Carl Zeiss in 1905. These binoculars used objective lenses and the design was such that the image was erected with a folded optical path.

While purchasing binoculars, you must consider the magnifying power and the field area as the two important factors. Magnifying power of binoculars is determined by focal length of the objective (objective means how much light is accumulated to form an image) that gives the linear power of the binoculars. For example, a liner magnifying power of 10 means that if you see an object from binoculars, it will look as if it was 10 times closer to you. If you are using handheld binoculars then you will be able to see the image without any problem. In other binoculars the image shakes. Also, large magnification leads to a smaller area of visibility. A field of view means the area that is visible with the binoculars. It is usually measured in yards or meters. For example, 900 meters or 900 yards

You can search for different types of binoculars on the internet. If you are interested in purchasing them, search on Google or ebay or other auctioning websites for cheap binoculars.