How to Calibrate Binoculars

If anyone's ever handed you a pair of binoculars and said, "Look at that!" and you've held them to your eyes and have seen an unclear image, it's because you need to calibrate the binoculars for your eyes. So whether you're birdwatching or trying to see up-close from nose-bleed seats at a football game, you'll need to calibrate your binoculars before you use them.

Difficulty: Easy

Instructions

1. Point the binoculars at an object approximately 30 feet away. A lettered sign works best for calibrating binoculars. Spread the two halves of the binoculars as far apart as you can. Hold them up to your eyes.

2. Set the two halves of the binoculars so they are as far apart as your eyes. Adjust the center focus knob or wheel between the two halves of the binoculars to the right as far as it will go.

3. Turn the diopter adjustment ring on the right eyepiece counterclockwise as far as possible. Close your left eye while you do this.

4. Open your left eye and close your right eye or cover the right lens. Adjust the center focus knob or wheel again until the object appears sharp and clear.

5. Adjust the diopter adjustment ring while covering the left lens until the lettering on the sign is clear. Uncover the left lens and look through the binoculars with both eyes. The binoculars are now calibrated.

Tips & Warnings

• Identify the diopter adjustment ring by it being marked with a "- 0 +." Some binoculars might have an additional number after both the "-" and "+" signs.
• Upon completing the calibration process, first pass over the sign, and then go back and fix on it to make sure you have achieved the sharpest focus.
• You may need to go through this process more than once to properly calibrate your binoculars.