chromatic aberration
71Refracting telescope — A refracting or refractor telescope is a dioptric telescope that uses a lens as its objective to form an image. The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used in other devices such… …
72Non-achromatic objective — A non achromatic objective is an objective lens which is not corrected for chromatic aberration. In telescopes they can a be pre 18th century simple single element objective lenses which were used before the invention of doublet achromatic lenses …
73Dollond , John — (1706–1761) British optician Dollond was born in London, the son of Huguenot refugees. He started life as a silk weaver but later joined his eldest son, Peter, in making optical instruments, and devoted years of experiment to developing an… …
74Meniscus corrector — Albert Bouwers 1941 catadioptric telescope with a concentric meniscus corrector A meniscus corrector is a negative meniscus lens that is used to correct spherical aberration in image forming optical systems such as catadioptric telescopes. They… …
75Maksutov telescope — A 150mm aperture Maksutov Cassegrain telescope. The Maksutov is a catadioptric telescope design that combines a spherical mirror with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly spherically… …
76Canon EF lens mount — The EF lens mount allows all the Canon EF lenses to be used on any of the Canon EOS line of cameras made by Canon Inc.Unlike the EF s breech lock predecessor, the FD mount, the EF mount uses a bayonet style mount. EF stands for Electro Focus :… …
77Condenser (microscope) — A condenser is one of the main components of the optical system of many transmitted light compound microscopes. A condenser is a lens that serves to concentrate light from the illumination source that is in turn focused through the object and… …
78light — light1 lightful, adj. lightfully, adv. /luyt/, n., adj., lighter, lightest, v., lighted or lit, lighting. n. 1. something that makes things visible or affords illumination: All colors depend on light. 2. Physics …
79Circle of confusion — For the closely related topic in microscopy, see Point spread function. In optics, a circle of confusion is an optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. It is also known as… …
80photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
