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Abbe number. 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 ...
The Canon EF 35-70mm f/3.5-4.5 is an EF mount wide -to- normal zoom lens. It is one of the first lenses in the Canon EF series. It has the same zoom system and 9 lenses in 8 groups layout as the Canon New FD 35-70mm f/3.5-4.5 [1] although it is unclear whether the actual optical design is identical. In October 1988, Canon announced the EF 35 ...
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 ...
The Canon EF 14mm f/2.8L USM is an ultra wide angle prime lens. It is the widest prime lens in the Canon EF series. Because it is corrected for a rectilinear projection, the field of view is less than that of the Canon 15mm fisheye . The front element of the lens is so prominent that it does not allow use of filters on the front.
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 ...
The EF 200mm USM lens is an L-series prime telephoto lens made by Canon Inc. for the EOS line of cameras. Four 200 mm primes were made: f/ 1.8, two f/ 2.8, and the most recent f/ 2.0. The 200 mm f/ 1.8 USM lens, introduced in November 1988, is the fastest 200 mm ever produced. [1] It is a large off-white lens with rear drop-in filter tray.
The EF 200–400 mm f/4L IS USM Extender 1.4× is an EF mount super telephoto zoom lens produced by Canon. It is part of the professional L-series and functions with the Canon EOS line of cameras. The EF 200–400 mm lens features an ultrasonic motor, image stabilization and weather sealing. It is the first and only EF lens with a built-in ...
Canon EF 85mm f/1.8 USM, a classic portrait lens. Canon makes several lenses for the EF lens mount and EF-S lens mount that are well-suited for portrait photography.These lenses may also be used for other purposes, often being suited for indoor sports photography as well, due to suitable focal length and wide aperture, though autofocus speed is an issue in sports photography that is less ...