Eye Relief

The eye relief of an optical instrument (such as a telescope, a microscope, or binoculars) is the distance from the last surface of an eyepiece at which the user's eye can obtain the full viewing angle. If a viewer's eye is outside this distance, a reduced field of view will be obtained. The calculation of eye relief is complex, though generally, the higher the magnification and the larger the intended field-of-view, the shorter the eye relief.

Read more about Eye Relief:  Eye Relief and Exit Pupil, Available Eye Relief, Adding Prescription Lenses

Famous quotes containing the words eye and/or relief:

    The body is no body to be seen
    But is an eye that studies its black lid.
    Wallace Stevens (1879–1955)

    Cows wandered through the streets.... Vegetables grew chiefly in cans, and stream-beds and caƱons glittered with these omnipresent signs of civilization.
    —Administration in the State of Colo, U.S. public relief program (1935-1943)