How to coose binoculars

How to choose binocularsWhich binoculars should you use?

This guide includes an extensive description of the various technical terms used for binoculars. But even without knowing all the ins and outs, here is a rough guide for what models you should consider for particular jobs.

'Opera glasses' are specialist binoculars for shows

Whichever you choose, stay between 6x and 10x magnification unless you plan to use a tripod. Check the magnification before you buy, and only go over 8x magnification if you have unusually steady hands. The higher the magnification, the more shaky hands will affect the image.

Which binoculars work best for which activities?

On a budget

Poro prisms, which have better image quality at lower prices.

Walking tours and holidays

Again, if you’re on a budget, look at poro prisms. But if you can afford it, also consider more expensive roof prisms, which are more compact and lighter.

Shows

There are standard types of binoculars known as 'opera glasses' designed specifically for watching theatre or opera. Or if you want something a bit more rugged you can also use outdoors, go for standard binoculars around 6x30 strength.

Sporting events

Look for binoculars with a wide 'field of view' (this is explained in 'Features Explained').

Hunting

If you are hunting in woods, you want a wide view and a strong image. So objective lens diameter may be more useful than magnification – at least until the binoculars become so bulky that they can’t be carried easily. 7x35 is ‘good for all-round field use’, where 6x30 is adequate for looking around a woods, or 8x35 or 9x35 for looking at birds of prey at a longer distance.

Star gazers need binoculars they can hold steady or mount on a tripod

Hunters should also ask about the 'twilight factor' of a pair of binoculars – how easy they are to use in reduced light. But be aware that this measurement is not measured in a standard way across all manufacturers, making it hard to compare different brands.

Astronomy

A pair of binoculars is quite a lot like two telescopes lashed together. But where telescopes are usually placed on tripods, binoculars are handheld, so it’s important that you pick a binocular with a magnification you can hold steady. For most people, this is 8x or below.

You also need as much light as possible, so pick the largest objective lens diameter you can easily carry. 7x50 to 9x63 are all useful, and even larger sizes can be used if you want to lug around a tripod.What binoculars are made of

A lens coating helps make things look brighter

What’s the difference between weather resistant and waterproof binoculars?

Waterproof binoculars are also known as 'nitrogen-filled'. If neither term is printed on the casing, the binoculars are probably not waterproof.

Waterproof binoculars are usually designed for marine use, and can be submerged in water. They typically cost more than £100, and are usually no more than 7x magnification. Any higher magnification would be wasted: it is even more difficult to hold binoculars still underwater than it is on land.

Weather resistant binoculars, on the other hand, should not be submerged.

Armouring

This is the covering that prevents a pair of binoculars being banged about. ‘Smooth’ armouring is easier to clean, ‘rugged’ armouring easier to grip.

Lens coatings

Before it reaches your eye, light can be reflected up to 16 times through a set of lenses in your binoculars.

If your lenses are not ‘coated’, each time light is reflected, some light is lost. As well as making the final image darker, the 'lost' light will reflect inside the binoculars, confusing the final image.

If you can afford it, try to get better lens coatings. Today, new surfaces called 'multi-coatings' are the best available.

From least to most effective, these are the coatings available:

• Coating optics: some surfaces, but not all, are coated.
• Fully coated: all air-to-glass surfaces are coated, but probably not any plastic surfaces.
• Multi-coated: some surfaces, but not all, are multi-coated.
• Fully multi-coated: all air-to-glass surfaces are muti-coated (this is the most effective, and the most expensive, approach).

Glass - BAK4 and BK7

BK7 is the cheapest grade of glass commonly used in binocular prisms. BAK4 is better quality. If your budget allows, buy BAK4-prism binoculars.