Binoculars are typically adjusted to fit your face and match your eyesight.
Binoculars are magnifying tools that use two refracting lenses -- or telescopes -- positioned side-by-side. Many binoculars are equipped with two prisms inside the tubes; the prisms change the light-beam direction, and flip the image to an upright position. Correct adjustment is necessary to properly view your targeted object.
Facial Spacing
Adjust the binocular's barrels to match the distance between your eyes. Hold the device in the viewing position; grasp each barrel. Move the barrels further apart -- or closer together -- until you see one circular field. Reset the binoculars before each use.
Diopter
Adjust the diopter setting of your binoculars by rotating the dial; it is typically located on the center-focus knob, or above the right eyepiece. Diopter is the unit of measurement for the magnifying capacity of the lens. A proper diopter setting improves sharpness by compensating for the visual differences in your eyes.
Diopter Setting
Set the diopter ring to zero. Cover the right lens with a cap, and look at a distant object while keeping both eyes open. Adjust the focus ring until the view is at its sharpest. Switch the cap to the left lens, and look at the same view. Turn the ring until you see the object clearly and sharply. Keep both eyes open and relaxed the entire time. Remove the cap and look through both lenses; the image appears sharp when the diopter is properly adjusted.
Eye Cups
The soft, rubber eye-cups -- found on the eyepieces -- are adjusted by folding or rotating down. This setting allows for more space on the eyepiece, and is designed to specfically accommodate those who wear glasses. Rotate the eye cups down so that the eyepiece is as flat as possible. Place the flattened eyepiece on the lens of your glasses.
Tags: both eyes, both eyes open, diopter setting, eyes open, ring until, your eyes
