Choosing Scopes for Outdoor Spotting
Spotting scopes, also called fieldscopes, are compact, tripod-mountable daylight telescopes, providing more magnification than standard field binoculars. Long-range magnification allows birders to pick out a single member of a flock in flight, or hunters to distinguish the structure of antlers against wooded backdrops. Target range shooters use them to locate hits on their marks, while hikers identify prospective trails from one mountaintop to another. You can also use them with digiscoping adapters to mount digital cameras or even smartphones for long-range photography.
Two fieldscope bodies are available. One has a straight body from the objective lens to the eyepiece. The other has an angled body, in which a straight barrel begins angling upward at 45 degrees at the imaging-prism housing, which in turn connects to the eyepiece. Straight bodies are easier to pack in outdoor gear and to manipulate by hand. Angled bodies are largely for tripod use. The viewing angle lets glassers easily focus on targets when the viewing position is at waist level and below.
Fieldscopes consist of barrels that often contain insert-reactive gases to prevent internal fogging due to weather extremes. For instance, Swarovski spotting scopes feature anti-fogging nitrogen, as well as a dry gas to prevent moisture buildup. Barrels also have a threaded connector for tripod mounting. The focusing and zoom mechanisms are either knobs on top of the prism housing or knurled wheels around the barrel directly in front of the housing.
The front of the barrel contains a fitting for spotting scope eyepieces, consisting of multi-lens elements to capture all three primary colors as well as corrections for contrast and color fidelity, simultaneously. Some eyepieces, such as those offered with Nikon scopes, are interchangeable, providing a full range of magnification options with just one instrument.
Different fieldscopes contain specialized lens and prism glass formulations with chemical coatings, yielding variable levels of optical clarity. Burris scopes, for instance, use high-density, low-dispersion glass with index-coated lenses to maximize color optics. All glass and coatings assist in the following ways:
Each scope features a set of three numbers on the casing. The first two numbers represent the range of magnification, such as 20-80x, meaning 20x zoom is the minimum magnification while 80x is the maximum. The last number is the diameter of the outer objective lens in millimeters.
Fieldscopes use a range of optics tripods and support equipment. Tripods must be sturdy, yet lightweight, readily adaptable to uneven terrain, and stable enough for gusty conditions. Other support equipment includes car window mounts for glassing on the go. A variety of camera T-mount adapters is also available for attaching photographic equipment to fieldscopes. Some instruments, such as Leupold scopes, come with full tripod and accessory kits.