Buying Binoculars On a Budget
by Steve Sorensen
(Originally published in the Warren Times Observer, March 20, 2010.)
Repairing a car, woodworking, household chores – we’ve all had times when we’d like to have four hands. For hunters, two hands are usually enough, but four eyes would be nice.
As in every personal decision,
you have much to consider.
The good news is that having a good pair of binoculars is like having four eyes – our natural peepers for looking near and optical assistance for looking far. But, with so many brands and so much fog to cut through, how does a person decide what to buy? What do hunters need to know when buying binoculars?
Some say that anything below top line is junk. If that’s true, most people will have to be satisfied with junk because few budgets include thousands of dollars for binos. Top end optics are essential in the hands of the professional hunter, the guide, or other specialists in the field. They use the principle that the more you use a set of optics, the better those optics need to be.
That’s the same principle you should use when shopping optics. There’s no shame in not buying the best European brand if you consider your purchase carefully and buy the best you can afford. Here’s a good starting point for choosing binoculars:
1. Decide your price range. Stretch a little, and you’ll be glad you did.
2. Decide what power you want – 7 through 10 is all most of us can hold steady without extra support.
3. Decide what size you want. You won’t use binoculars that are too small to let much light reach your eyes, or so large that they’re cumbersome.
4. Decide where you will use them. If you keep them in the car or look through the kitchen window you won’t need waterproof binos. For outdoor use, waterproof is a must.
Those four issues, price, power, size and waterproofing, are not matters of quality. But once you’ve made those decisions, it’s time to consider the quality issues.
The first quality issue is what the glass prisms inside are made from. Usually we have two choices: BK7 and BaK4. What you want is BaK4 glass. It’s denser, lets more light through, and produces less eyestrain.
Next, consider the lens coatings. Anti-reflective coatings prevent light from being reflected away from its path through the binoculars. But be warned. The term “coated” might mean only one glass surface has a single coating. “Fully coated” means all glass surfaces are coated. “Multi-coated” might mean only one surface has more than one coating. Don’t settle for those. You need every surface coated multiple times.
What you want is “fully multi-coated,” which means that every glass surface, inside and out, is coated multiple times. That’s important when you realize that some binos have 10 or 12 glass surfaces, and each surface reflects about 5 percent of the light striking it.
Now consider the numbers. Compact binos of 8 x 25 have 8-power magnification with a 25 mm objective lens. (The objectives are the lenses at the end of the binoculars opposite your eyes.) 8 x 25 is small, lightweight and handy, but might not serve you well.
Simple math tells you the size of the little round beam of light that will reach your eyes. It’s called the “exit pupil.” Divide the number 25 by 8. Those binoculars will deliver an exit pupil to your iris of just over 3mm, smaller than your iris in low light, so less than you need if you’re going to use them at the edges of darkness.
An 8 x 50 pair of binoculars will give you an exit pupil of more than 6mm, about all that most eyes can use. Every pair of binoculars between the compact 8 x 25 and the full size 8 x 50 will be a compromise of weight, size and optical brightness.
There is more to consider, including rubber armor coverings, a comfortable neck strap, adjustment for distance between your eyes, using with or without eyeglasses, and more. But those are the basics, and enough information to show that buying a pair of binoculars is a personal decision. It has a lot to do with comfort. That’s why Vickie Gardner, Vice President of Alpen Optics says, “When is buying binoculars like buying shoes? Always.”
Like shoes, binoculars come from many companies, and in many sizes, styles and price ranges. As in every personal decision, you have much to consider.