Thebinocularshop Binocular Buying Guide

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Welcome to thebinocularshop Binocular Buying Guide




With this guide we hope to help you to buy the binocular that is perfect for your needs. We at thebinocularshop know all about binoculars, after all we sell THOUSANDS each year. Have a read through this guide and feel free to email us with any queries you may have.



Binoculars are normally referred to by two numbers eg 8x40, 10x50. The first of these numbers is the actual magnification of the image: the size to which the subject is enlarged. The second number is the size, in millimetres, of the objective (front) lens. This is an important figure: for the same given magnification the bigger the objective lens the brighter the image will appear. Therefore, an 8x40 will have the same magnification as an 8x30 but the image will appear brighter.

A tiny (honest) bit of maths follows: The brightness of binoculars of differing magnifications can be ascertained by dividing the objective lens size by the magnification. This gives us the exit pupil diametre in millimetres.. Therefore a 10x50 (exit pupil 5mm) will have the same brightness as an 8x40 (exit pupil 5mm) and brighter than a 16x50 (exit pupil 3.1mm). This figure should always be kept in mind when purchasing binoculars, especially if they are to be used in poor light.




Binoculars can be categorised into the traditional size (8x40, 10x50 etc) and the smaller, more lightweight compact binoculars (8x21, 10x25 etc). If the brightness of them image is of most importance then we would recommend either a 7x50, 8x40 or 10x50; if a small size and weight is more important then take a look at our large range compact binoculars.

We strongly recommends a magnification of around 7,8 or 10x. Higher magnificatios may make the subject appear larger but they have a much narrower field of view (so you infact see less) and you will need to carry around a tripod, monopod, beanbag or a stone wall to rest the binos onto to hold the image steady.

General Use

Any binocular in our range with a magnification of 8x or 10x is perfect. Points to consider are the size/weight against the brightness of the image. Remember that a compact binocular is likely to be used much more than frequently than a large pair. In recent years compact binos have become more popular and while they do not offer the brightness in poor light of an 8x40, they are significantly lighter and smaller.

Bird Watching

The traditional binocular for birdwatching has been the 8x40/42. These offer the advantages of brightness, wide field of view and a binocular that can be held steady.

Hiking and Walking

In these activities where size and weight are of maximum importance and we have no hesitation in recommending a 8x21(25) or a 10x25 compact.


Here people have traditionally chosen a 7x50 which offers wonderful low light capabilities along with a manageable magnification on a moving boat. Try to get one with waterproofing (for obvious reasons) and nitrogen filled. This last feature stops the internal lenses steaming up should the binos be taken from a warm cabin to a cold deck. We do a really easy to use focus free marine binocular for minimum fuss.

Night Sky

When viewing the night sky we want a binocular that gives a reasonable magnification with a large exit pupil diameter. A 7x50 fits the bill perfectly and will enable you to see stars that are less bright than say a 12x50 would.

Air Shows and Sporting Events

Here we have fast moving objects a reasonably long distance away. Popular choices for these activities are either an 8x or a 10x magnification. Choose either a traditional for brighter image eg 8x40 or 10x50 or a more compact 8x21(25) or 10x25.


We hope this guide has been of use to you. Please feel free to email us with any queries you may have.

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