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by Mike Stiles
BinocularsWhen beginning birders start to get more serious, they feel the need to put down their grandfather's hunting binoculars, or the tiny opera glasses they had lying around the house, and purchase something they can actually see through. Binoculars come in a dizzying array of sizes, magnification, and even the types of glass used in construction, with prices to well over $2,000. There are three main aspects to keep in mind when binocular shopping - magnification, eye relief, and close focus. Every binocular has two numbers associated with it, 10x42 for example. The first number is the magnification and the second number is the diameter of the objective lens (the big end) in millimeters. Dividing the second number by the first will give you the exit pupil diameter, which relates to the amount of light delivered to the eye. In our example above, our exit pupil diameter is 4.2mm. In an 8x35 binocular, another popular size, the exit pupil is 4.37mm (35 divided by 8), which allows slightly more light to reach the eye and allow more detail, especially in low light situations. As you can imagine, there are trade-offs and considerations for both numbers. While the 10 power brings the subject in closer, the binoculars tend to be slightly heavier. 10x50 binoculars are very big and hard to hold still. They would be great for hawk watching but not for finding small warblers in the willows. An 8x26 binocular is compact and easy to carry all day, but allows far less light through the glass. Keep in mind that larger magnification will slightly decrease the field of view. For eyeglass wearers, the eye relief number is an important consideration. This number is the distance between the lens closest to your eye, and where it focuses with the entire field of view visible. Try this. Look through your binoculars and move them away from your eye. The field of view will decrease as you move away. Glasses hold the binoculars away from your eye, so to obtain the greatest field of view, eyeglass wearers will need 15mm or more in eye relief. Remember to fold or twist the eye cups down if you wear glasses. Believe it or not, birders need a binocular that focuses at a very close range. When that mega-rare bird is in the branch just above your head, you don't want to have to back up to see the bird clearly. Some binoculars will allow you to focus on your shins. A close focus of around six feet will be appreciated by all birders, and is great for butterflies too. Spotting ScopesMany birders will never buy a spotting scope, but to get that far away look at a bird, or to study birds in great detail, a scope is essential. Here again, the choices are daunting and a good scope, tripod, and swiveling head can be downright expensive. The two main choices are size of the scope and the eyepiece magnification. Scopes are measured by the diameter of the objective lens. Smaller scopes range in the 600mm size to around 800mm for a larger scope. Remember, you have to carry the thing around, so the weight of the larger lensed scope is worth considering. Eyepieces come in either a zoom (20X-60X is a common size) or a lens of fixed magnification. It's a matter of personal choice, and every birder will tell you why theirs is better. My scope has a wide-angle eyepiece of 32 power. It is a great lens, but sometimes I wish for the higher power for distant birds. On many scopes the eyepieces are interchangeable and if I had an extra $400, I would have both. TripodsBe sure to purchase tripod legs that are tall enough for you to stand erect while viewing, and are sturdy enough to hold your scope upright in the wind. The swiveling head should be easily moveable in all directions, such as a video type head. It is always worthwhile to look through many different binoculars and scopes to see which one you prefer. Participate in a field trip and talk to the birders about their optics. Most will let you look through them, especially if the birding is slow. How they feel in your hand and ease of focusing are important considerations. Study the online sites and pay attention to the specifications. Visit local vendors and birding festivals (the Morro Bay Winter Bird Festival is on Martin Luther King weekend) and look through the binoculars and scopes there to see which feels right to you.
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