Ever Wonder The Mechanics Behind The Workings Of A Pair Of Binoculars?

A lot of people use binoculars on a daily basis for a variety of reasons and they certainly know how to use them in terms of pointing and observing at anything of interest, but a question widely asked is how do they work? For such a product that is really only used to magnify anything in its field of view, it is actually very technical and there are a lot of features and clever materials to make binoculars work. When you look at a set of binoculars you will find it much resembles two telescopes that are simply connected together – and that uses roughly the same technology except binoculars require a couple of extra “mirrors” to work with.

Below we will look at the individual materials used to build the binoculars and what each of them does to produce the end results.


Firstly we will have a look at the structure of a set of binoculars, you will notice that the eye cups you look through in some cases do not align with the lenses at the other end, so in theory if a set of binoculars didn’t have anything inside, it would almost be like looking through a dark tunnel with a little bit of light at the end of it. This is why the lenses play an important role, and depending on the size of the lenses will depend on how much light they can capture – the more light will provide a brighter and clearer view through the binoculars.


The object Lens comes from the Latin word Lentil, which is more or less a piece of glass that is curved in shape. This is important when it comes to reflecting light behind it and into the binocular structure ready for other materials to do their work. Lenses come in different shapes and sizes depending on what the specific manufacturer of the binoculars wants to achieve. They also come in different forms of glass and are often coated in different materials to provide an enhanced crystal clear view for the binoculars users. You will find that the more expensive binoculars use their own lens technology to produce better results for their users.


Carrying on from above, for binoculars to work properly requires a lot of science to be involved. Firstly, a term called refraction is used when the light bends in the air and another material “captures” it, that is what refraction is and the material can be anything such as liquid water or glass. This is primarily what the lenses achieve by capturing the light and that then gets sent into the binoculars to be used for other materials to do their next job. The next job would be for the selected prism design to do its work and we’ll have a look below at what that involves.


If you look through a magnifying glass sometimes the view will look upside down, which is why the introduction of “Prisms” are introduced at this point of the binoculars structure – these Prisms will put the observation the right way up again. There are 2 different types of prisms, again depending on the manufacturer’s preference, and these are the PorroPrisms and the Roof Prisms. The Roof Prisms are often just back to front chunks of glass, and the Porro Prisms are also back to front chunks of glass but aren’t completely aligned, they often mirror the light 90 degrees towards the next prism, and the next prism then mirrors the light towards the eye cups which allows you to see. Depending on which prisms the manufacturers use will change the overall design of the binoculars, some Roof Prism designs are quite narrow and lighter, whereas Porro Prisms provide better quality sights but are heavier and in turn makes the binocular design a bit chunkier. This then brings us to the eye piece lenses.

Eye piece lenses

There are usually two lenses that are back to front again which magnifies the view for the user to see, the prisms and the front lenses have done all the work and these eye piece lenses are just there to magnify the view.


This is just a simple guide of how a set of binoculars work and you will find that a lot of binoculars produced by different manufacturers uses differently technology to produce different quality results, and the higher-end binoculars have better ways of producing such results thanks to the more expensive materials they implement into their designs. If you are very interested in seeing how a set of binoculars work in close detail, the best thing you can do is buy a cheap set of binoculars you can open up and mess around with – check out their individual components and you will have a better understanding of how they work and what kinds of materials they use.