WHAT BINOCULARS SHOULD I CHOOSE?

Dom Holtam sifts through the jargon to help us understand binos better – and how to choose the right ones

There are lots of complicated terms and numbers used in the marketing of binoculars. But which ones are there to impress the potential punter and which ones really help you understand what you are buying?

What do the numbers mean?

When you are looking at binoculars, they are always described with two numbers. For example, 8x32 or 10x42. The first number refers to the magnification – in other words, how much closer to you whatever you are looking at will appear to be. The second refers to the effective diameter of the objective lenses at the front of the binoculars. So a 10x42 binocular has a 10 times magnification and 42mm objective lenses.

A low diameter objective keeps the overall size and weight down – ideal for compact travel optics. However, a large objective lets in more light, allowing for superior performance in low light conditions. The downside is increased size and weight.

While a high magnification can really help with long-range quarry or trophy identification, anything over 10x is very hard to use without the aid of a rest or tripod. If you feel you really need more than 10x, you might be better off with a spotting scope.

Prism systems

Every binocular has a system of glass prisms inside. The prism system reduces the size required for the optical path, keeping the length of the binocular compact and user-friendly. The prism also turns what would be an upside-down image the right way up. There are two types of prism systems: roof and porro.

ROOF PRISM SYSTEM

In roof prism binoculars, the prisms overlap closely, allowing the objective lenses to line up directly with the eyepiece. The result is a slimmer and more streamlined shape in which the lenses and prisms are in a straight line.

Roof prism binoculars are less bulky than an equivalent porro model and often considered more ‘modern-looking’.