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At a difference of 3 diopters the lenses would however be very visibly different—one lens would need to be at least 3 mm thicker and have a base curve increased by 7.5 spheres. Example [ edit ] Consider a pair of spectacles to correct for myopia with a prescription of −1.00 m −1 in one eye and −4.00 m −1 in the other.
An aspheric lens or asphere (often labeled ASPH on eye pieces) is a lens whose surface profiles are not portions of a sphere or cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens . The asphere's more complex surface profile can reduce or eliminate spherical aberration and also reduce ...
Apochromat. Chromatic aberration of a single lens causes different wavelengths of light to have differing focal lengths. An apochromat, or apochromatic lens ( apo ), is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses. The prefix apo- comes from the Greek ...
This variation is called vignetting, and can be corrected by selectively brightening the perimeter of the image. Flat-field correction ( FFC) is a digital imaging technique to mitigate the image detector pixel-to-pixel sensitivity and distortions in the optical path. It is a standard calibration procedure in everything from personal digital ...
The Canon AL-1 was an FD mount, 35mm single-lens reflex camera introduced in March 1982. Its main feature was the "Quick Focus" focus-assist system that was aimed at those who had trouble focusing through the viewfinder—either novices, or those with poor eyesight—and was intended to head off competition from the first full-autofocus cameras from other manufacturers, such as the Pentax ME F.
Dimensions. 96.6 × 146.7 × 48.3 mm. Weight. 795 g. Made in. Japan. The Canon New F-1 replaced the F-1n (an upgraded F-1) as Canon 's top-of-the-line 35mm single-lens reflex camera in September 1981. Like the earlier models, the New F-1 takes FD-mount lenses. Although no date has ever been confirmed, it is thought that the last New F-1 was ...
The Canon EF 600mm is a super-telephoto lens made by Canon Inc. The lens has an EF mount to work with the EOS line of cameras. f / 4L USM lens was released in November 1988 (923,000 yen). f / 4L IS USM lens was released in September 1999 (1,290,000 yen). f / 4L IS II USM lens was announced in February 2011 (US$12,999 at release, now US$11,499).
Light being refracted by a spherical glass container full of water. Roger Bacon, 13th century. Lens for LSST, a planned sky surveying telescope. The word lens comes from lēns, the Latin name of the lentil (a seed of a lentil plant), because a double-convex lens is lentil-shaped. The lentil also gives its name to a geometric figure.