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:
“His eye begets occasion for his wit,
For every object that the one doth catch
The other turns to a mirth-moving jest.”
—William Shakespeare (1564–1616)
“Do not be discouraged, if in a thousand instances you find your kindness rejected and wronged, your good evil-spoken of, and the hand you extend for the relief of others, cast insultingly away; the benevolence which cannot outlive these trials of its purity and strength, is not like the self-sacrifice of him, who went about doing good.”
—C., U.S. women’s magazine contributor. American Ladies Magazine, pp. 331-4 (July 1828)