To get the most from your hunting glass, make sure it's adjusted for your eyes!
by Wayne van Zwoll
All binoculars worth using must be focused. If you encounter a binocular with "permanent" or "automatic" focus, shun it as you would a bouquet of poison oak. Such a glass is not only of inferior quality; it will strain your eyes.
"I-F" or individual-focus binoculars have a focusing dial on each barrel. When adjusting for a new distance, you must re-focus each separately. Here's how: With both eyes fixed on the distant object, cup your left palm over that objective lens, and focus the right-hand barrel for your right eye. Reverse, and repeat the process for your left eye. Be sure you're looking at the same object!
"C-F" or center-focus binoculars are more popular. They feature a center focusing wheel, plus a dial on one (typically the right-hand) barrel. The dial may also be mounted on the hinge with the center wheel. To focus, hold your right palm over the right-hand objective lens, then turn the center wheel until your chosen target appears tack-sharp to your left eye (remember: keep both eyes open!). Now cover the left-hand lens and use the dial to focus the right-hand barrel for your right eye. When you want to glass at a different distance, you need only turn the wheel, as it moves both optical systems in tandem. You've already compensated for disparities in vision, right and left. C-F binoculars are not optically superior to I-F glasses; but they are faster to use.
Tip: Keep your binocular focused as close as you might see game. There's usually time to focus for a long look, but you'll want instantly sharp images of animals that must be shot quickly.