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:
“But the lightning which explodes and fashions planets, maker of planets and suns, is in him. On one side elemental order, sandstone and granite, rock-ledges, peat-bog, forest, sea and shore; and on the other part, thought, the spirit which composes and decomposes nature,—here they are, side by side, god and devil, mind and matter, king and conspirator, belt and spasm, riding peacefully together in the eye and brain of every man.”
—Ralph Waldo Emerson (1803–1882)
“What this country really needs is a good five-cent cigar.”
—State of Indiana, U.S. public relief program (1935-1943)