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Focusing Scopes |
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Every birder should use a spotting scope. This is a sure way to open new birding opportunities and add more species to a bird list. Whether you observe in the great wide open or locally at your city park, a spotting scope will add a new dimension to your birding.
We all know that there are times when you need more than the usual 7x to 10x binoculars. On a recent eagle count, for instance, we used spotting scopes to find several eagles that were missed by observers with binoculars. The scopes were essential for distinguishing adult birds from immatures at those extreme distances.
But spotting scopes are not just for eagle counts and other specialty work. Many birders today use a spotting scope at least as much as binoculars, if not more, and for all types of birding. My scopes see constant use as I drive my bird routes or watch the action at several of my neighbors' feeders (with permission). For me, and many others, a spotting scope is as much a necessity as binoculars.
What I like best about a spotting scope is the way it allows a birder to observe sensitive species such as cranes, eagles, and shorebirds at safe, friendly distances. As more and more people take to the field, it is becoming more important to observe in ways that are minimally disruptive and stressful to birds and other wildlife. The greater reach of the spotting scope makes it ideal for any time I need to keep my distance. It is my first choice for observing nesting birds, or for birding in many refuges, sanctuaries, and other sensitive areas where access is limited.
Yet some birders avoid spotting scopes because they are more difficult to use than binoculars. Higher magnifications with smaller fields of view and the discomfort of one-eyed observing can be frustrating, especially when the action is fast and furious, but all these obstacles can be mastered with a little practice. Any birder who can use binoculars can learn to use a spotting scope.
The higher magnification of a spotting scope is, of course, a double-edged sword. As magnification increases, many other things decrease: field of view, image brightness, image steadiness, and sometimes image sharpness. And higher magnifications are much more sensitive to atmospheric turbulence and pollution. This is a big price to pay for a larger image, but in optics there are no free lunches.
The challenge in using a spotting scope is to make magnification work for you and not against you. The basic rule of thumb is to use magnification sparingly--never sacrifice image detail or steadiness for image size. Small, steady, and sharp beats big, wobbly, and fuzzy every time, especially on small subjects like birds. Too little magnification in a spotting scope is better than too much, especially with a scope that does not offer a choice of magnifications (after all, you may be able to get closer).
When using a scope, always begin at the lowest available magnification (widest field of view) and work up as needed. If you start at high magnification, a bird often flies away before you find it in the narrow field of the scope. Find that sparrow in the wider, more friendly field of 20x (20 power) first, then switch to 40x or higher if necessary. When you've finished, be sure to switch back to lower magnification to be ready for the next bird.
The first skill to master with a scope is lining up the target -- finding a bird in the narrow field of scope. This can be frustrating at times, but there are ways to make it easier.
As mentioned, a wide field of view is still the best solution. This invariably means low magnification, but special wide-field eyepieces can help. These eyepieces are available as options on many scopes and are usually 20x to 25x in magnification. They can offer as much as 40 percent more field than a conventional eyepiece of the same power, and nearly 100 percent more field in some cases than a zoom eyepiece at the same magnification. Add a standard eyepiece of 40x to 50x to one of these special eyepieces for a scope system that will handle nearly any situation.
If you wear glasses, pay particular attention to eye relief; this will be the single most important feature for determining the field of view. Look for eyepieces that offer at least 14 mm or 15 mm of eye relief if you expect to see a full field of view with glasses (remember more is better when measuring eye relief—18 mm is better than 14 mm). My favorite scope sports a 20x eyepiece with 20 mm of eye relief and a nice wide field of view. I don't miss too many birds with that combination.
Some scopes feature aiming devices such as peep sights or notches in the body. These are useful at any magnification but are real stress reducers at high magnification. If your scope doesn't have one, you may be able to fabricate one with some tape or by marking the barrel of your scope.
You can also learn to point your scope without the help of an aiming device, although this takes more skill. The best approach is to keep magnification low and practice. Since every scope is a little different, you will have to work out a pointing system that works best for you.
Spotting scope eyepieces can be fit to a scope body at different angles, which also affects a scope's pointability and ease of use. Straight-through eyepiece scopes are the most common and feature an eyepiece that is in line with the scope body. Angled-eyepiece scopes, on the other hand, have the eyepiece mounted at 45 degrees or so to the scope body. Although some observers have a strong preference for one or the other, each configuration has its advantages.
Most people find the straight-through models to be the easiest to aim, at least at first. The straight-through scope is also the best choice for observing birds on the ground or at eye level. This is also the most convenient version to use when viewing from the tight quarters of a vehicle or a small blind, or when your scope is attached to a camera or a shoulder stock.
Angled-eyepiece scopes are awkward to aim at first, but with a little practice they line up as quickly as straight-through models. This version eliminates much of the neck strain that occurs when observing birds perched high in a tree or on a mountainside. This is also the best scope to use on a tripod, since it can be kept lower, which adds to stability. There are two additional advantages of scopes with angled eyepieces. They are easier to share among birders of differing heights, and they are more comfortable to use for nighttime stargazing. Personally, I find angled eyepeices to be the most comfortable for extended viewing.
No matter what scope you choose, practice is the key. Take your scope out in the backyard and randomly line up on convenient objects until you build up speed. This will pay off in the field when that rare or accidental species makes a sudden appearance. Don't worry if you sometimes miss a bird when the action is hot -- even experts fumble at times.
Eye fatigue is the second big obstacle to overcome in a spotting scope, and it is more of a problem than in binoculars. Two eyes are definitely more comfortable to use than one, especially if you don't learn to use the one properly. You can't use a spotting scope comfortably for long periods until you develop good observing techniques.
First, use your better eye if one is stronger or sharper than the other, as is the case for most people. This will help minimize eye strain to some extent and will give you the sharpest possible view. If you have astigmatism, wear your glasses when you observe, for the same reason. If you are nearsighted or farsighted, this can be corrected by focusing the scope.
Next, keep both eyes open when you observe. This is by far the most difficult technique to learn when using a scope, but it is also the most essential. Contrary to what some experts might tell you, closing one eye when you observe is the worst thing you can do. This pulls the muscles of one eye more than the other, which quickly leads to tired eyes and blurry vision. You simply cannot use a scope for long periods if you observe with one eye squeezed shut.
Of course, leaving both eyes open is much easier said than done; it requires some practice. At first you will be distracted by the image from your off-eye (non-scope eye) as you try to concentrate on the image in the eyepiece. This is natural, and to be expected, so you will have to make a conscious effort to keep your off-eye open.
First, relax both eyes totally when you observe. Squinting in your scope eye quickly leads to squinting in the other eye, and squinting is a very difficult habit to break. To avoid squinting, use the focuser on the scope constantly to make fine adjustments -- that's why it's there. Relaxed eyes are the key to all-day observing in a spotting scope, or even with binoculars.
Second, use your master eye as your scope eye. This is your stronger eye, but not necessarily the right eye if you are right-handed or left eye if left-handed, since many people are cross-dominant in this regard. At any rate, it is easier to ignore the image produced by your weaker eye when it, instead of your dominant eye, is used as your off-eye.
It also helps keep your scope eye as close to the eyepiece as possible. This will minimize the effect of the unwanted image from the off-eye and also keep unwanted lateral light from causing a glare in the eyepiece.
If you absolutely cannot manage the both-eyes-open technique, you can compromise by only partly closing the off-eye. This is still much better than squeezing it all the way shut. Another solution is to place a hand over the off-eye (but keep it open) as you observe, assuming you have one hand free to do so.
Anyone who is not using a spotting scope these days is missing out on some wonderful bird watching opportunities. I know a few birders who use a spotting scope for virtually all of their birding. That's a bit extreme, but there's no question that the scope is a potent observing tool, albeit a demanding one. It is well worth the effort to learn how to use it.