Choosing the right binoculars
When choosing a pair of binoculars, it is well worth spending some time on deciding what you want them for. Binoculars go hand in hand with watching birds, so for this exercise I will take bird watching as the preferred interest.
Deciding what to buy can be daunting, as there is a vast number of makes and models to choose from. I will assume that the bird watcher will visit moorland, woodland, lakes and waterways and probably the coast. This would also include watching birds in your own garden. The first consideration will be magnification, and x7 to x10 would be a good range to choose from. If much of the bird watching will be done in the garden then x7 will suffice, but if you will be spending more time on moorland or lakes, it would often be better to have a higher magnification such as x10. The best all rounders would be x8 or x9.
The diameter of the objective lens usually balances with the magnification, so x7 comes with a 30mm objective lens, x8 with a 40mm lens and x10 with a 50mm lens. These figures are commonly written as 7×30, 8×40 and 10×50. There are many variations but for our purpose here, it is not necessary to describe every one.
If you expect to be going out in all weathers, waterproof models would certainly be best.
Cost is a major factor for most people, and while you can buy a decent pair of second hand binoculars for £50, spending more on a good quality pair can make all the difference. Whilst there are some excellent quality binoculars on the market costing well over £500, it is worth noting that as the cost increases, the quality usually becomes more marginal. You are also paying for the latest innovations of engineering of which some are arguably unnecessary.
An essential part of choosing binoculars is to test a few pairs. See how they feel in your hands. Take them outside the shop and see if they are comfortable with your eyes against the rubber eyecups. Adjust the focusing and look for sharpness and clarity. Check that the image through the eyepieces is sharp, not only in the centre but around the edges as well.
New binoculars should have been thoroughly tested and checked before leaving the factory, but there is one fault that can sometimes be found on brand new instruments. This is collimation errors. More commonly known as alignment, these errors occur when binoculars are knocked and a prism moves out of alignment. So look for double vision, and if there is any, ask for another pair to test. A case or bag should be supplied with your new binoculars, as well as lens caps, strap and a lens cleaning cloth. Straps on cheaper binoculars are often narrow and uncomfortable, so spending e few extra pounds on a wider and cushioned strap is well worth the investment. This is especially the case if you envisage spending a lot of time using your binoculars in the field. Tripods can be a very useful accessory for prolonged observational work, and especially when using higher magnification models.
Spectacle wearers need to take extra care when choosing binoculars, with the main consideration being eye relief and field of view. (see section on Field of View). The type of eyecups fitted should also be tested. Most are now rubber and either fold back, lift up or screw on. It is a matter of what works best and feels comfortable with the size and shape of spectacles worn.