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In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist who defined it.
In optics, the Abbe sine condition is a condition that must be fulfilled by a lens or other optical system in order for it to produce sharp images of off-axis as well as on-axis objects. It was formulated by Ernst Abbe in the context of microscopes. [ 1] The Abbe sine condition says that. the sine of the object-space angle should be ...
Low-dispersion glasses are particularly used to reduce chromatic aberration, most often used in achromatic doublets. The positive element is made of a low-dispersion glass, the negative element from a high-dispersion glass. To counteract the effect of the negative lens, the positive lens has to be thicker.
The Canon EF 75-300mm f/4-5.6 IS USM (Japan) [178] of 1995 was the first interchangeable lens with built-in image stabilization (called Image Stabilizer; for Canon EOS 35mm SLRs). Image stabilized lenses were initially very expensive and used mostly by professional photographers. [179] Stabilization surged into the amateur digital SLR market in ...
See Canon EF lenses for the product line-up. See Canon EF-S lenses for the product line-up. EF-S lenses are built for APS-C 1.6x crop sensors, so they only work with models that use this sensor size. When EF-S lenses are used on a 35mm (full frame) camera the back element will hit the mirror assembly or cause substantial vignetting since the ...
Ernst Abbe. Ernst Karl Abbe HonFRMS (23 January 1840 – 14 January 1905) was a German businessman, optical engineer, physicist, and social reformer. Together with Otto Schott and Carl Zeiss, he developed numerous optical instruments. He was also a co-owner of Carl Zeiss AG, a German manufacturer of scientific microscopes, astronomical ...
Corrective lens. A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye.
It is the successor of the Canon EOS 350D, and upgrades to a 10.1 megapixel CMOS sensor, a larger continuous shooting buffer, an integrated image sensor vibrating cleaning system (first used in a Canon EOS DSLR), a more precise nine-point autofocus system from the EOS 30D, improved grip, and a bigger 2.5-inch (64 mm) LCD with 230,000 pixels and a larger viewing angle which replaces the top ...