Hunting Optics
Optical Equipment for the Hunter
Today’s hunter is faced with a terrific array of optical equipment: spotting scopes, binoculars, telescopic sights, and assorted aiming devices. The optics simplify sighting by placing all the images on the same focal plane. They define objects better; that is, they provide a very sharp image of the object in question. The sharp definition combined with magnification and the ability to focus clearly on an object helps in identification and evaluation of wildlife, whether as potential trophies or simply for viewing enjoyment.
Power, focusing ability, and definition affect the clarity of an image; and some understanding of that interaction is needed to select the right tolls for the job at hand. Power refers to the magnification of the image. Focus defines the sharpness of an image, much like the focusing knob of a projector permits the operator to adjust for image clarity. Definition depends on power, stability, and the sharpness of the focus. Technically, it is the resolving power or the ability to separate lines that are close together. Different situations demand different selections. A sighting device for close range pistol shooting may be very different from one intended for hunting pronghorns on the prairies. One may have a fixed focus, while the other may be adjustable for various ranges. A spotting scope serves a similar but different function from a pair of binoculars. That difference is based largely on the power of the optics.
Telescopic sights have a variety of reticules or aiming devices, too. They may have cross hairs (or wires), tapered or duplex cross hairs, posts, dots, or some combination. Each one has advantages and disadvantages. Posts are heavy and easy to see under poor light conditions or when sighting on moving game. Dots give some measure of distance by subtending (covering) a certain number of minutes of angle (one minute of angle or MOA is approximately 1 inch at 100 yards), but they may cover too much of the field at longer ranges or may be too fine for use under poor light conditions. Cross wires may be difficult to see if fine and may share the disadvantages of posts if they are coarse. Duplex reticules are a compromise, relatively coarse cross wires or tapered posts with fine cross hairs between them. Some scopes even include stadia lines to help estimate distances. Those multiple cross wires can be confusing in situations demanding rapid sighting. The bottom line is that there is no single best reticule. You need to pick one that matches the conditions and the preferences you face.
Some Numbers and Their Meanings
Power is usually defined by X’s. A 6X telescopic sight, for example, magnifies an image 6 times or makes it appear to be only 1/6th as far away. As power increases, the size and mass (weight) of the optical device usually increases. Sensitivity to movement and to mirage (the shimmering effect of “heat waves” or differences in air density) also increases with power. Both the width of the field of view and the relative brightness of the instrument decrease with power unless the power increase is balanced by an increase in the size of the objective lens (the lens toward the object being viewed).
The size of the objective lens is usually stated in binoculars. The binoculars may be 7x35, 8x44, or some other designation. The first number states the power. The second number states the diameter of the objective lens in millimeters. As with power increases, increases in objective lens size involve some increase in bulk and weight. Relative brightness or exit pupil size increases with increasing lens diameter within a given power. Thus, brightness is about the same for 7x35, 8x40, and 10x50 glasses.
Many scopes or binoculars will list the field of view or the width of the area that can be seen through them at some specified distance, usually 100 or 1000 yards. That field of view increases with lens diameter and decreases with power. Wide-angle lenses will increase the field of view, but they do so at some cost in sharpness or image clarity near the edges of the field. A wide field of view makes finding an object in the lenses easier.
Selecting Tools to Fit the TaskOptical equipment should be selected with the intended uses in mind. How far away will the objects being viewed be? Binoculars used for close range bird watching may not be appropriate for the hunter in mountainous country or on the prairies. What kind of light conditions will prevail? The deep woods hunter may require much higher relative brightness than would the desert or prairie hunter.
What kind of objectives do you have for the tool? Will your scope be used to evaluate trophy quality or merely to find bedded game? Will you be looking for fine detail or merely trying to see if a large animal is present? Will the riflescope be used for short ranges (under 75 yards) or for precision varmint hunting at 400 yards?
How much precision is needed? Will it matter if you make a mistake of a couple minutes of angle or fail to see a pale spot in front of the eye?
How important are the size and weight of the equipment? The still hunter who is using glasses merely to check for antlers at moderate ranges may be able to get by with very small glasses. The trophy hunter for mountain or plains game may feel that the extra size and weight of the spotting scope and big binoculars are simply part of doing business.
What kind of treatment will the equipment need to face? Armored optics are designed to take a fair amount of abuse without damage. Some of the less expensive equipment may be ruined by a minor amount of abuse. The equipment that is to be bounced around behind the seat of a 4x4 needs more protection than that worn carefully around the neck of a foot-borne hunter.
Some optical equipment is chosen for a single purpose. A varmint hunter may want a high-powered scope with fine cross hairs and parallax adjustment for precision, long range shooting. A squirrel hunter may want a .22 scope with heavy cross hairs and permanent parallax adjustment to 25 yards. IF the same rifle were to be used for both situations, a different, more versatile scope would be the answer – perhaps a variable scope with duplex reticules. Equipment for special applications may be ideally suited to that application but poorly suited to others. Versatile equipment may not be the best for any given situation, but well adapted to a wide variety of situations.
Consider the features of any item you may select. High quality lenses are the beginning of high quality optics. They should be bright, clear, and free of distortion. Pick optics that are bright enough for the conditions that you will face. Be sure the reticule fits your needs, not those of the sales person or the advertiser. Ask questions about durability (check the warrantee) or toughness. Talk to people that have used the equipment, asking them specifically about any problems they may have encountered.
Availability and cost will influence your selection. To some extent, you get what you pay for; but you may find bargains among less expensive brands if they meet your needs. The optical field is broad, and many specialists may have unfamiliar names outside that specialty. If the equipment meets your needs dependably, it is right for you regardless of other factors.
Using Optical Equipment
Optical equipment can add considerable safety margins to hunting. Absolutely positive target identification is a fundamental rule for safe hunting. A riflescope should never be used to scan the terrain for game or to identify another hunter. Remember, the scope is an aiming device for the rifle. You cannot look without pointing the business end where you are looking. Very few experienced hunters have not turned a stump into a big buck or made similar errors. That condition is known as early blur. Under some conditions, early blur will help us to see what we expect or hope to see. That condition may persist in the mind long enough to shoot before the truth is known unless one takes time to be sure first. Binoculars, spotting scopes, and even riflescopes help here.
Movement makes definition of an image very difficult. With binoculars, the thumbs and index fingers can be graced against the forehead and cheekbones to steady them. For long-range work, the elbows can be braced against the knees much like the sitting position in shooting. For the average person, holding anything higher than about 8x binoculars steady without support is extremely difficult. In fact, research shows that the definition of 12x glasses is often about the same as 6x binoculars. Spotting scopes generally have much higher power than binoculars – 15-60x. As a result, they almost always require support of some kind. Lower powered scopes may be used effectively with a padded rest where tremor is not too severe. Usually, however, either a tripod or a car window mount is needed for best results. Tripods come in a variety of heights for use prone, sitting, or standing. The window mount is almost indispensable for the hunter using a vehicle to locate and evaluate game. Be sure to turn off the ignition, or the vibrations of the engine will cause some tremor in the image. With a riflescope, tremor can be reduced by using a padded rest (something at hand, like a rock, standing tree, fence post, or log), a pair of shooting sticks, or the steadiest position available.
Combining the precision in aiming afforded by a good riflescope with a good rest or supported shooting position makes good sense for a hunter. When life and death are in the balance, as in a hunting situation, using every advantage to make a well-placed killing shot is not cheating. It is evidence of a good ethical training for the hunter.
Excellent optical equipment is of very little use if the user does not know how to extract the most from it. Locating things with optical help requires both strategy and practice. When possible a wide field of view should be used to locate the object of interest. The human eye has a very broad field of view, and it makes an excellent searching device. When an object of interest is sighted, the observer need only bring the scope or binoculars into position while looking at it. Avoid the tendency to look into the instrument before searching for the object. When variable power is available, try using the lowest power to locate the object, and then switch to a higher power to study it further.
When long range searching is prescribed, the terrain should be searched systematically. A set of reference points could be used to scan the area completely, moving between pre-selected points on the terrain. While searching, the observer should be alert for parts of the animal, not merely whole ones. Eyes, ears, noses, tails, legs, and antlers or horns are often the clues to the rest of the beast being in the same vicinity. When trying to point out an individual to another observer, use horizontal and vertical “clock faces” and prominent landmarks to define the position. Sometimes the easiest method is simply to locate the animal in the scope and let the observer focus for his or her eye.
One of the most common uses of optical equipment is to evaluate the trophy potential of an animal. Although groups of animals often give a person the chance to pick the biggest, widest, etc., lone specimens can be very difficult to judge. Thorough knowledge of the animal is necessary to do a good job of judging quality. Often the ears, the width of the body, or some similar feature can be used as a relative measure. Even then, unusually proportioned individuals may cause errors.
Basic Recommendations
For general use and eastern hunting, 7X binoculars with 25-50mm objectives are usually adequate. Spotting scopes have limited use, except for varmint hunting or other similarly specialized purposes. Riflescopes are usually fixed 4X or variable power. Slug guns and handguns are usually equipped with non-magnifying or 2X scopes because of their use in relatively close quarters where higher magnification on a long eye relief scope may cause shot placement problems.
In more open country typical of much mountain, desert, or prairie hunting, a spotting scope becomes almost as important as a flat shooting rifle. Riflescopes tend to be somewhat more powerful, 6X or higher magnification variables being the rule. Binoculars of 8-10X (some even use 12X) are much more useful. Handguns may still use relatively low magnification scopes, but shotgun slugs are used much less often for big game.
