A close up look at what to consider when buying field glasses
No matter what, where or how you hunt, binoculars should definitely be on your list of must-have gear. With so many options to choose from, however, finding the right model to suit your needs and budget can be tricky. Here are the most important features to consider.
Most binoculars in your local hunting store will have a magnification within the 8x to 15x range, although it’s certainly possible to find magnifications as low as 6x and as high as 25x or more. Is a higher magnification better? For some applications it is, but not always, as there are compromises with greater power. For starters, a higher magnification means you’ll have a narrower field of view, which limits your glassing effectiveness in some situations. As well, hand movements are amplified with higher magnifications, making for an unsteady view (anything higher than 10x typically requires a tripod or window mount). Greater power also means the objective, or front, lens will usually have a larger diameter, adding weight and bulk.
Binoculars don’t gather light, they transmit it. And you always lose some light to reflection, either externally or inside as the light passes through prisms and bounces off mirrors. While it may seem that objects in dim light appear brighter when viewed through binoculars, that’s merely a result of the magnification.
A large objective lens let’s in more light than a smaller one, but much of that light can be lost to internal reflection. Manufacturers apply specialized coatings to reduce reflection, but not all are the same. Coated glass is not as effective as multi-coated, and neither performs as well as fully multi-coated, where more of the internal surfaces are covered.
Be aware, too, of the power-objective lens ratio, as that determines the size of what’s known as the “exit pupil,” the amount of light that passes through to your eyes. The exit pupil size is calculated by dividing the size of the objective lens (in mm) by the power. For example, 10X50 binoculars have 5mm exit pupils (50 divided by 10), which is sufficient for Canada’s legal hunting hours. I recommend shopping for binoculars in the evening, and testing them outdoors before you decide what to buy.
Most modern binoculars are touted as being fog-, dust- and waterproof. This is accomplished by purging the interior of the binoculars with nitrogen or argon gas before they’re sealed to remove any internal moisture. This eliminates the problem of lenses fogging up on the inside, while rubber O-ring seals keep out any dust or moisture. I wouldn’t recommend any binoculars that don’t have this protection.
Likewise, armour coating is pretty standard these days, helping to cushion the internal components from damage if the binoculars are dropped or banged. Check before you buy, but virtually all brand-name hunting binoculars come with this protection.
Prisms are pieces of glass cut at precise angles to reflect light. In binoculars, they are used to correct the orientation of the image you see (when the image is first captured, it appears upside down; prisms turn the image right side up).
The other function of prisms is to bend the light path so that binoculars can be more compact in design; otherwise, they would be much larger.
There are two prism styles in binoculars, porro and roof. Porro prism binoculars feature a dogleg-style design, making for a sharp and bright image. While they’re typically more economical to construct—and therefore cheaper to buy—the trade-off is they’re generally bulkier and heavier. Roof prism binoculars, meanwhile, are typically more compact and robust, but they lose more light than comparable porro prism models. They are also more costly.
#5 DECISION TIME
Consider all the variables when deciding what’s best for your needs. Will you be hunting forested landscapes, or open country? Will you be walking considerable distances, or remaining more stationary? Do you plan to travel to hunt? How much can you afford to spend?
The most popular hunting binos today are 8×42 roof prism models, and perhaps 10×42 versions for the wide-open West. It’s easy to default to a higher magnification, but remember you’ll be sacrificing field of view, as well as adding bulk and weight. Whatever you choose, there’s no substitute for selecting a pair that feels good to you—and offers a clear view.