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 eye by long use comes to see even in the darkest cavern: and there is no subject so obscure but we may discern some glimpse of truth by long poring on it.”
—George Berkeley (1685–1753)
“Passing through here in 1795, Bishop Asbury commented, ‘The country improves in cultivation, wickedness, mills, and stills.’ Five years later, he held a meeting in the neighborhood and remarked that he thought most of the congregation had come to look at his wig.”
—Administration in the State of Sout, U.S. public relief program (1935-1943)