By Joe Arterburn
A little understanding goes a long way toward making shopping for a binocular not nearly as complicated as it may seem when faced with the variety of brands, models, styles, sizes, magnifications and prices available today.
First, understand you are choosing a binocular—that is the correct term, not binoculars nor pair of binoculars. The “bi” refers to the twin barrels that make up the single unit of a binocular.
Today, there are two basic binocular designs: porro prism, which feature a “dogleg” barrel design through which light reaches your eyes via a system of internal mirrors; and roof prism, which features a more streamlined, compact design.
Either style will perform a binocular’s basic function, which is to magnify objects to show detail you cannot see with your eyes alone.
Magnification is designated in the numbers on the binocular. For instance, the “8” in 8x40 denotes a magnification factor of 8. The 40 denotes the diameter in millimeters of the objective, or front, lens. There are binoculars with less magnification, some with more; some with smaller diameter objective lenses, some with larger. Understanding the numbers and what they mean to how well you can see detail in different lighting situations, such as early in the morning or as the sun fades in the evening, is important to choosing the right binocular for you. Resolution, the clarity with which you view an object through your binocular, is key. Generally speaking, large objective lenses provide more detail than smaller ones.
If it is any help, today’s top-selling binoculars are 8x32 and 10x42 models, both of which provide good magnification and light transmission throughout most of both ends of the day. Plus, they are versatile and available in a variety of price ranges.
A few other points. On most binoculars, focus is adjusted via a center wheel though some offer individual focus of each lens. If speed is a consideration, choose center focus.
You’ll hear about lens coatings, which are important. During the 1930s, a Zeiss engineer named Smakula found that adding a coating of magnesium fluoride to lenses dramatically increased light transmission. Because of Smakula’s discovery, current high-quality binoculars feature multiple coatings to enhance light transmission. Other coatings provide benefits, such as scratch-resistance and improved viewing in wet, rainy conditions.
Don’t be confused by various acronyms and initials affiliated with binoculars. You’re likely to see initials like ED, FL and HD which may mean something to you—extra-low dispersion, fluoride-containing and high-definition, respectively—but the best test is to compare binoculars side-by-side to see which provides the clearest, brightest image and, importantly, feels comfortable in your hands—and you won’t mind carrying during a long day in the field.
There are other considerations, which a knowledgeable salesperson can walk you through.
Most outdoor experts will advise you not to scrimp. There is often considerable difference between the best and the next best. Purchasing a binocular should be approached as an investment that will last a long time. Plus, the best binoculars provide crisp, clear viewing which just might make the difference in catching the glint of a buck’s antlers in the underbrush.