There are basically two types of optical equipment used for bird watching: binoculars and spotting scopes.
Binoculars are one of the birdwatcher's essential tools. While it is possible to watch birds without them, the close-up views you can get with them can be breathtaking!
Most bird watching magazines carry advertisements for binoculars and other equipment and often have regular reviews too.
Remember to try the binoculars for yourself before you buy them, because only you know what is best for your hands and eyes.
Most, if not all, binoculars have the same main features, such as eyepieces, central focussing wheel, dioptre adjustment and objective lenses. In addition, most have two numbers and usually a few letters marked on them, for example: 8x40W BGA.
|40||Objective lens diameter (mm)|
|GA||Rubber or polyurethane armour|
The first number is the magnification. In our example the magnification is 8x, which means that whatever you look at through the binoculars will seem to be eight times larger or eight times closer than if you looked at the object with just your eyes.
The second number is the diameter of the objective lens. In our example, the diameter of the objective lens is 40 mm. The larger the objective lens, the more light can enter the binoculars and the brighter the image, but the binoculars will also be bigger and heavier.
Different manufacturers often use a variety of letters to indicate various features. However, the common ones are quite standard:
Some other recent letters: AG (silver coated), PC (phase correction), HG (high-grade), P* (Zeiss phase coating), and T* (Zeiss multi-coating) provide information about special coatings used to improve the colour and clarity of the image.
Most people do not have two eyes the same - one is usually "weaker" than the other - and so it is important that this difference is accommodated by the binoculars. Binoculars should have an individual eye (or dioptre) adjustment, often on one of the eyepieces, but sometimes part of the main central focussing mechanism.
Do not be tempted to simply buy the binoculars with the largest magnification and objective lens, such as 20x50, because these will be very heavy and difficult to hold still. The most common magnifications are 7x and 8x and these are great for most types of bird watching, especially in woodlands where you are often trying to follow moving birds, but if you plan to do a lot of bird watching at lakes and estuaries where birds are often further away then 10x are better.
As a rule of thumb, the objective lens should be about 4-5 times the magnification; this provides a good compromise between the amount of light entering your eye and the weight of the binoculars (objective lens diameter); typically, therefore, 7x32, 8x40, 10x42 or 10x50.
There are basically three main types of binoculars.
The porro prism type is the classic binocular shape with the eyepieces closer together than the larger objective lenses. There is vast range of manufacturers offering a huge selection of sizes and features.
I bought my first pair of binoculars, a pair of 8x40s, when I was about 7 years old for about £20 and they last for just over 20 years before the focussing mechanism broke. I replaced these with a pair of Olympus 8x42 EXPS for about £120. These are quite lightweight at 790 g (about 28 oz) and are rubber armoured and have fold-down eyecups. The right eyepiece incorporates the dioptre ring for individual eye adjustment, this tends to move unintentionally but a rubber band wrapped around it stops this from happening.
Roof prism binoculars tend to be more compact than porro prism and have better light-gathering properties.
The Leica 10x42 BA are my main pair of binoculars, which I bought in May 2000 after starting to go out on field trips and particularly to wetlands.
I wear spectacles and so it is important to have binoculars with substantial eye-relief so as to avoid the usual "tunnel vision" problems. Also, I wanted a pair of robust and reliable binoculars, hopefully to last me a life time! The individual eye adjustment is incorporated in the central focussing mechanism. They
weigh about 890 g (31½ oz).
I was undecided between these and Swarovski 10x42 SLC binoculars. The latter have eyecups that twist out rather than pull out, which is a nice touch, and the focusing wheel turns more smoothly than the Leica's. However, I did not find the position of the wheel to be convenient, but the Leica binoculars were easy to focus - first and second fingers finding the wheel easily. Both offer magnificent images.
Compact or miniature binoculars tend to be either small roof prism binoculars or "reverse porro prism" ones, which have the objective lenses closer together than the eyepieces. Both types are handy for putting in your coat pocket when you do not plan on bird watching, but don't want to be caught without!
My compact binoculars are the reverse porro prism type: Nikon 8x21CF Sprint II, which weigh just 220 g (c. 8 oz). The eye cups fold-down and the right eyepiece provides the individual eye adjustment. I find them terrible to use with spectacles - the rubber eyecups rub against the spectacle lens and cause the dioptre adjustment to move and looking through the eyepieces feels like looking through a keyhole.
My mother has a much better pair of binoculars, a pair of 8x32 RSPB FG.PC, though not strictly compact they are small enough to put in a large coat pocket or day sack. They are roof prism binoculars with phase coated optics for extra clarity and brightness, waterproof, rubber armoured, have push down eyecups and are incredibly comfortable to use.
The image you see through them is excellent.
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