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Zoom lens print that page


A zoom lens is a mechanical assembly of lens elements for which the focal length (and thus angle of view ) can be varied, as opposed to a fixed focal length (FFL) lens (see prime lens ). They are commonly used with still , video , motion picture cameras , projectors , some binoculars ,

Optics print that page


electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics , treats light as a collection of rays that travel in straight lines and bend when they pass through

History of optics print that page


postulated an interaction between rays from the eyes and rays from a source such as the sun. In his Optics Greek mathematician Euclid observed that "things seen under a greater angle appear greater, and those under a lesser angle less, while those under equal angles appear equal". In the

Nonimaging optics print that page

The two design problems that nonimaging optics solves better than imaging optics are: [ 3 ] solar energy concentration : maximizing the amount of energy applied to a receiver, typically a solar cell or a thermal receiver illumination : controlling the distribution of light, typically so

wikipedia.org | 2011/8/9 1:59:39

Contact lens print that page


A contact lens (also known simply as contacts for a pair) is a corrective , cosmetic , or therapeutic lens usually placed on the cornea of the eye . Leonardo da Vinci is credited with describing and sketching the first ideas for contact lenses in 1508, but it was more than 300 years later

Fresnel lens print that page


A Fresnel lens ( / f r eɪ ˈ n ɛ l / fray- nel ) is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses . The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that

Corrective lens print that page


A corrective lens is a lens worn in front of the eye , mainly used to treat myopia , hyperopia , astigmatism , and presbyopia . Glasses or "spectacles" are worn on the face a short distance in front of the eye. Contact lenses are worn directly on the surface of the eye. Intraocular lenses

Fourier optics print that page


dimensional space, and t represents time. [ edit ] The Wave Equation in the Time Domain Fourier optics begins with the homogeneous, scalar wave equation (valid in source-free regions): where u ( r , t ) is a real valued Cartesian component of an electromagnetic wave propagating through

Optical aberration print that page

Aberrations fall into two classes: monochromatic and chromatic . Monochromatic aberrations are caused by the geometry of the lens and occur both when light is reflected and when it is refracted. They appear even when using monochromatic light , hence the name. Chromatic aberrations are caused

wikipedia.org | 2011/4/19 8:54:58

Camera lens print that page


A camera lens (also known as photographic lens , objective lens or photographic objective ) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image