Don't be fooled by binocular hype. Getting a good price on a good, bright,
sharp, durable binocular isn't hard. You just have to resist the silly ads and
know a few basics, which you can read right here.
When bino shopping, forget all
about "seeing 10 miles" and "the vision of an eagle." Don't pay attention
to words like "bright, clear, precise or sharp." Those are vague buzz words and
glittering generalities. You need hard facts.
The fact is binoculars are confusing and complicated because they're a black
box. You can't see in there to determine what parts are good or bad or even
what they're doing. So I'll tell you:
There are two basic binocular types, roof prism and Porro
prism. Roofs have straight barrels; Porros have
dog-legged barrels. You'll pay more to get a roof that's as sharp as a Porro, but roofs are more durable, harder to knock out of
alignment. Pay about $250 and up for a good roof prism; $150 and up for good Porro. Most folks go with roof because they're more compact
and "in fashion."
The critical stuff you want in a roof prism are: Phase-coated BaK-4 prisms
with silver mirror, or more expensive dielectric mirror,and fully multi-coated lenses. This means every air-to-glass surface is coated
with several layers of anti-reflection coating. This maximizes light
transmission and minimizes flair and glare. Coatings cost more, but don't add
weight or bulk. An 8X is more versatile than a 10X and easier to hold steadily.
A 6X is even better for use in woods.
Now, here are some details to help you understand why the above features are
A binocular consists of an objective lens. That's the big one out front that
captures the light and forms the image. This image is then sent, upside down
and backward, to additional lenses inside that correct for various aberrations, such as color shift and distortion. Next come the
prisms, hefty chunks of glass that reorient the image properly and bounce the
light back and forth in order to lengthen its travel. This is what creates
magnification. The farther the light travels, the higher the magnification,
which is why old telescopes were so long. Prisms shorten the barrel by bouncing
the light from surface to surface. Then they pass it to the eyepiece lenses
that act like a magnifying glass to further increase magnification. This is why
many 8X and 10X binoculars are the same length. There's just additional
magnification in the eyepiece of the 10X.
Next, the prisms have to be precisely ground and mounted. Cheap internal
parts that hold things together can contribute to poor image quality,
particularly after a bino has been used, worn and
bumped around a bit. This is hidden quality you can't see, but need. A brand's
reputation for durability counts here.
Phase coating improves sharpness of light coming out of roof prisms. Porro prisms don't need it. A silver mirror is much
brighter than a cheaper aluminum mirror, and dielectric mirrors are the brightest
of all, but you pay more for them.
Anti-reflection lens coatings are your biggest bang for buck. Uncoated glass
reflects (wastes) about 4 percent of the light at each surface, coming and
going. So one lens will cost you 8 percent of light.
With an average of five lenses in a binocular, uncoated glass costs significant
brightness. Worse, the reflected light bounces around inside like a billion
ping pong balls, creating haze, flare and glare. Anti-reflection coatings, the
more the better, can knock reflection loss down to less than .5 percent per
lens surface. To make sure you get it, insist the binocular is FULLY
multi-coated. If they advertise it as coated, it needs just one layer on one
lens. Multi-coated means multiple layers on at least one
lens. Fully multi-coated means all lenses get it. That's what you want.
The objective lens lets in light. Magnification reduces light. An 8x40 fully
multi-coated is bright enough to see game clearly 45 minutes after sunset.
Going to a 50mm objective might give you one to three more minutes more viewing
time. A 10x40 is slightly darker than an 8X and a 6X is slightly brighter.
Shop The Sportsman's Guide great selection of Binoculars!
Ron Spomer has been photographing and writing
about the outdoors for nearly four decades. He's written seven books, hunted on
six continents and been published in more than 120 magazines. He's currently rifles'
editor at "Sporting Classics," Travel columnist at "Sports Afield," Field
Editor at "American Hunter" and "Guns & Ammo" -- Optics Columnist at "North American
Hunter," Contributing Editor at "Successful Hunter," Senior Writer at "Gun
Hunter," and TV host of "Winchester World of Whitetail." He will write on Shooting Tips weekly for sportsmansguide.com. You can read his
blogs and catch some of his YouTube videos at www.Ronspomeroutdoors.com.