The quick answer

Set the eyecups (extended without glasses, retracted with glasses), fold the barrels until you see one round image, then focus your left eye with the center wheel and your right eye with the diopter ring. Note your diopter setting so you only have to do it once.

Key takeaways
  • Eyecups up without glasses, down with glasses.
  • Adjust the hinge until you see a single round image.
  • Use the center wheel for your left eye and the diopter for your right.
  • Brace your elbows or use a rest for a steadier view.

Set the eyecups

Eyecups hold your eyes at the right distance from the eyepieces. Without glasses, twist or pull them fully out. With glasses, retract them so your lenses can get close. If you see a dark ring or a narrow view, adjust them a click at a time.

Set the width (interpupillary distance)

Hold the binoculars to your eyes and fold the barrels together or apart until the two circles merge into one sharp, round image with no black edges. Most binoculars show a number on the hinge; note yours.

Set the diopter

  1. Pick a target. Choose a detailed object at a medium distance.
  2. Close or cover your right eye. Or cover the right objective lens with your hand.
  3. Focus with the center wheel. Turn it until the image is sharp for your left eye.
  4. Close or cover your left eye. Now look with your right eye only.
  5. Focus with the diopter ring. Turn the ring, usually on the right eyepiece, until the right eye is sharp.
  6. Note the setting. Remember or mark the diopter position.

Field tipDo this setup in daylight before the season. In the field, you then only need the center focus wheel.

Glassing steadily

  • Brace. Rest your elbows on your knees, a pack, or a tree.
  • Use a tripod. Higher magnification binoculars benefit from a tripod adapter.
  • Scan in a grid. Move slowly across the terrain in overlapping strips rather than sweeping.
  • Rest your eyes. Take short breaks to avoid fatigue on long sessions.

Care in the field

Use lens caps, blow off dust before wiping, and clean lenses with a lens pen or microfiber cloth. Let fogged binoculars warm up gradually rather than wiping them repeatedly.

A few good questions.

What does the diopter on binoculars do?

It compensates for differences between your eyes so both see a sharp image at the same time.

Should binocular eyecups be up or down?

Up, or extended, if you do not wear glasses; down, or retracted, if you do.

Why do I see two circles in my binoculars?

The barrels are not set to your eye width. Fold them until the two circles merge into one.

How do I hold binoculars steady?

Brace your elbows on something solid, or mount the binoculars on a tripod, especially at 10x and above.

Gear that helps.

HuntingGear review

Vortex Diamondback HD 10×42

Best forHunters and hikers glassing more open terrain

A versatile 10×42 binocular with a rubber-armored body, adjustable eyecups, and a field of view built for scanning country.

Read our verdict

Our approach

Written by Outdoor Gear Verdict Editorial. Grounded in binocular manufacturer setup instructions. Always follow local regulations and the manufacturer instructions for your equipment. Read our editorial standards.