The key to choosing binoculars and telescopes comes down to the ability to test in 'field' conditions, comparing like for like products in an unhurried manner. If you cannot see further than a few hundred yards/metres, and/or find yourself looking at the inside of a shopping centre or high street it's unlikely you'll have made the correct choice.
All in focus shops and field events have the viewing facilities that will allow you to make the right decision, guided by our highly knowledgeable staff that work commission free and have many years experience in both optics and birding.

Choosing binoculars isn't always easy, and sometimes advertisements make exaggerated claims. Only you can make the choice, bearing in mind price, performance, size, durability, and your own particular needs. At the bottom line, ask yourself 'Does this binocular feel OK to me?' If the answer's a definite 'Yes', go ahead and buy.

What do the figures mean?

In all binocular specifications, two sets of figures are supplied (eg 10x40). Sometimes there's a letter as well, such as B or GA. The first figure indicates magnification the number of times the image is enlarged. This is usually 7x, 8x, 9x or 10x, but you can get binoculars of 12x and 16x as well. The second figure indicates the diameter of the 'objective lens' - the lens furthest from your eye. (The measurement is in millimetres.) The larger this lens, the more light reaches your eye. It's this measurement that determines the physical size of the binoculars. The letter B means that the eyepieces (usually with fold-down rubber cups) aresuitable for people who wear glasses. You can use these binoculars while wearing your glasses without losing much field-of-view.
'GA' means that the binoculars are rubber covered to protect them against wear and tear. Some manufacturers use 'BA' to mean that the binoculars are rubber-covered and have fold-down eyepiece cups.
The field-of-view is sometimes given in degrees, rather than, for example, '140m at 1000m'. A rough guide: 1 degree is approximately '17m at 1000m'.

What magnification do I need?

Generally, the lower the magnification the wider the field-of-view the brighter the image the easier to use without a support the closer you can focus. So 7x or 8x are ideal if you are using a telescope as well, or for woodland use, or at sea, or in poor light. They are recommended if you're walking, too, being easier and quicker to use. You get good depth of field, and you don't have to keep refocusing.
10x are the best compromise, however, if you aren't using a telescope as well. They focus down to about 15 feet as a rule, but are still manageable for distance work.
The higher the magnifications the narrower the field-of-view, the duller the image, the more difficult to hold steady.
High magnification binoculars are more suitable for hidework, viewing at estuaries and reservoirs, and when you're not using other optical instruments as well.

What type of binoculars do I need?

There are two main body types: the traditional porroprism design, with an angled body shape, and the roofprism (or 'Dach') design, with its 'straight through' look. Roofprisms are more expensive. They have internal focusing which is more robust and protects the optics, and they are more compact.
Both designs are available as fullsize instruments (eg 10x50 or 10x40). You can also get them in a more compact form (eg 8x30) or as a pocket field glass (eg 8x20 or 9x25).
Miniature binoculars are fine as backups to your fullsize ones and when you need them to be small and light. But miniatures don't have the same light gathering power or field-of-view as the larger binoculars do. Undoubtedly the best for birdwatching are the top quality roof prisms.

Conclusions

As well as magnification and type, you need to think about the way the binoculars handle: are they comfortable to use? Is the weight and size manageable? Think about the optical quality, the image brightness, the field-of- view. What are you going to use the binoculars for hide-work, estuary viewing, in woodland or in the garden? Are you going to use them frequently and in rough conditions? if so, you need to choose a durable pair, maybe checking for waterproofing. Are you going to use them for insect watching and long range plant study as well? If so, make sure they have good close-focusing ability.
For general birdwatching, go for the lowest usable magnification together with the most compact body shape (eg 8x32 or 8x42). If you need high-definition, a wide field-of-view and brightness of image, more than you need to consider size and weight, then try 7x42 or 8.5x42. For hide work, the best bet is around 10x40 or 10x50.