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:
“Therefore I have uttered what I did not understand, things too wonderful for me, which I did not know. ... I had heard of you by the hearing of the ear, but now my eye sees you; therefore I despise myself, and repent in dust and ashes.””
—Bible: Hebrew, Job 42:3-6.
Job to God.
“What do we want with this vast and worthless area, of this region of savages and wild beasts, of deserts, of shifting sands and whirlwinds, of dust, of cactus and prairie dogs; to what use could we ever hope to put these great deserts, or those endless mountain ranges, impenetrable and covered to their very base with eternal snow? What can we ever hope to do with the western coast, a coast of 3,000 miles, rockbound, cheerless, uninviting and not a harbor in it?”
—For the State of Kansas, U.S. public relief program (1935-1943)