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Double Gauss
The double Gauss lens is a compound lens used mostly in camera lenses that reduces optical aberrations over a large focal plane. Design The double Gauss lens consists of two back-to-back Gauss lenses (a design with a positive meniscus lens on the object side and a negative meniscus lens on the image side) making two positive meniscus lenses on the outside with two negative meniscus lenses inside them. The symmetry of the system and the splitting of the optical power into many elements reduces the optical aberrations within the system. There are many variations of the design. Sometimes extra lens elements are added. The basic lens type is one of the most developed and used photographic lenses. The design forms the basis for many camera lenses in use today, especially the wide-aperture standard lenses used on 35 mm and other small-format cameras. It can offer good results up to with a wide field of view, and has sometimes been made at 1.0. Extra wide aperture f/1.4 Double ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Gauss
The double Gauss lens is a compound lens used mostly in camera lenses that reduces optical aberrations over a large focal plane. Design The double Gauss lens consists of two back-to-back Gauss lenses (a design with a positive meniscus lens on the object side and a negative meniscus lens on the image side) making two positive meniscus lenses on the outside with two negative meniscus lenses inside them. The symmetry of the system and the splitting of the optical power into many elements reduces the optical aberrations within the system. There are many variations of the design. Sometimes extra lens elements are added. The basic lens type is one of the most developed and used photographic lenses. The design forms the basis for many camera lenses in use today, especially the wide-aperture standard lenses used on 35 mm and other small-format cameras. It can offer good results up to with a wide field of view, and has sometimes been made at 1.0. Extra wide aperture f/1.4 Double ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alvan Clark
Alvan Clark (March 8, 1804 – August 19, 1887), born in Ashfield, Massachusetts, the descendant of a Cape Cod whaling family of English ancestry, was an American astronomer and telescope maker. Biography He started as a portrait painter and engraver (c.1830s-1850s), and at the age of 40 became involved in telescope making. Using glass blanks made by Chance Brothers of Birmingham and Feil-Mantois of Paris, his firm '' Alvan Clark & Sons'' ground lenses for refracting telescopes. Their lenses included the largest in the world at the time: the at Dearborn Observatory at the Old University of Chicago (the lens was originally intended for Ole Miss), the two telescopes at the United States Naval Observatory and McCormick Observatory, the at Pulkovo Observatory (destroyed in the Siege of Leningrad; only the lens survives), the telescope at Lick Observatory (still third-largest) and later the at Yerkes Observatory, which remains the largest successful refracting telescope in the wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volkseigener Betrieb
The Publicly Owned Enterprise (german: Volkseigener Betrieb; abbreviated VEB) was the main legal form of industrial enterprise in East Germany. They were all publicly owned and were formed after Nationalisation#Germany, mass nationalisation between 1945 and the early 1960s, and the handing back in 1954 of some 33 enterprises previously taken by the Soviet Union as War reparations, reparations. The managing director of a VEB was called a plant or works manager (German: ''Werkleiter'', ''Werkdirektor'' or ''Betriebsdirektor''). He or she was assisted by the first secretary of the factory party organisation (''Betriebsparteiorganisation'') of the Socialist Unity Party of Germany, SED, and the chairman of the factory trade union (''Betriebsgewerkschaftsleitung''). Subordinate to them were roles such as "Chief Accountant" and "Technical Director". VEBs were initially vertical integration, vertically integrated into units called Associations of Publicly Owned Enterprises (''Vereinigung V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-lens Reflex Camera
A single-lens reflex camera (SLR) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits the photographer to view through the lens and see exactly what will be captured. With twin lens reflex and rangefinder cameras, the viewed image could be significantly different from the final image. When the shutter button is pressed on most SLRs, the mirror flips out of the light path, allowing light to pass through to the light receptor and the image to be captured. History File:Hasselblad 1600F.jpg, Medium format SLR by Hasselblad (Model 1600F), Sweden File:Zenza BRONICA S2 with ZENZANON 100mm F2.8.JPG, Medium format SLR by Bronica (Model S2), Japan. Bronica's later model—the Bronica EC—was the first medium format SLR camera to use an electrically operated focal-plane shutter File:Asahiflex600.jpg, The 1952 (Pentax) Asahiflex, Japan's first single-lens reflex camera. File:Contaflex BW 2.JPG, The Contaflex III a single- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
135 Film
135 film, more popularly referred to as 35 mm film or 35 mm, is a format of photographic film used for still photography. It is a film with a film gauge of loaded into a standardized type of magazine – also referred to as a cassette or cartridge – for use in 135 film cameras. The engineering standard for this film is controlled by ISO 1007 titled '135-size film and magazine'. The term 135 was introduced by Kodak in 1934 as a designation for 35 mm film specifically for still photography, perforated with Kodak Standard perforations. It quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film size. Despite competition from formats such as 828, 126, 110, and APS, it remains the most popular film size today. The size of the 135 film frame with its aspect ratio of 1:1.50 has been adopted by many high-end digital single-lens reflex and digital mirrorless cameras, commonly referred to as " full frame". Eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Panchro
In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is not the same as velocity. Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph). For air and marine travel, the knot is commonly used. The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum ''c'' = metres per second (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opic
The Overseas Private Investment Corporation (OPIC) was the United States Government's Development finance institution until it merged with the Development Credit Authority (DCA) of the United States Agency for International Development (USAID) to form the U.S. International Development Finance Corporation (DFC). OPIC mobilized private capital to help solve critical development challenges and in doing so, advanced the foreign policy of the United States and national security objectives. By working with the U.S. private sector, helped U.S. businesses gain footholds in emerging markets, catalyzing revenues, jobs, and growth opportunities both at home and abroad. It achieved its mission by providing investors with financing, political risk insurance, and support for private equity investment funds when commercial funding could not be obtained elsewhere. Established as an agency of the U.S. government in 1971, OPIC operated on a self-sustaining basis at no net cost to American t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooke Optics
Cooke Optics Ltd. is a camera lens manufacturing company based in Leicester. Administratively speaking, Cooke Optics is a spin-off of the company Taylor-Hobson. However, Taylor-Hobson used to be a lens manufacturer and Cooke lenses used to be its sole activity before Taylor-Hobson moved to the market of metrology instruments. Hence the foundation of Cooke Optics can be regarded as the foundation of Taylor, Taylor and Hobson (TTH) in 1886, and Cooke Optics can be regarded as the successor of the original Taylor, Taylor and Hobson business. The name Cooke originally came from the company T. Cooke & Sons of York, a manufacturer of telescopes. The optical manager of that company, H. Dennis Taylor (no relation), devised the Cooke triplet lens in the 1890s. Cooke of York was not interested in the manufacture of camera lenses, and licensed this design and others to TTH. Subsequently many of TTH's own designs, though unconnected with Cooke of York, also carried the Cooke brand. The Cook ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horace William Lee
Horace William Lee was an optical designer responsible for developing multiple influential lens designs, including the ''Opic'' (1920), an asymmetric large-aperture double Gauss lens, and the inverted telephoto wide-angle lens (1930), while working for the English optics firm Taylor, Taylor & Hobson (TT&H), which manufactured lenses in Leicester under the Cooke brand. Lee's designs helped to develop the modern cinematography industry, with high-speed lenses enabling sound synchronization, and the inverted telephoto providing enough space for a beam-splitter apparatus to capture color. Early life and education Horace Lee was born in January 1889 and graduated from Cambridge University in 1911 with a Bachelor of Arts degree. He married Grace Burrows (1893–1981) in March 1919 and the couple had three sons. Burrows was an accomplished violinist and teacher who helped to organize the Leicester Symphony Orchestra. Career Lee started at TT&H in 1913 as the assistant to prolific de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. Chromatic aberration manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image. Types There are two types of chromatic aberration: ''axial'' (''longitudinal''), and ''transverse'' (''lateral''). Axial aberration occurs when different wavelengths of light are focused at different distances from the lens (focus ''shift''). Longitudinal aberration is typical at long focal lengths. Transverse aberration occurs when different wavelengths are focused at different positions i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeiss Planar
The Zeiss Planar is a photographic lens designed by Paul Rudolph at Carl Zeiss in 1896. Rudolph's original was a six-element symmetrical design. While very sharp, early versions of the lens suffered from flare due to its many air-to-glass surfaces. Before the introduction of lens coating technology, the four-element Tessar, with slightly inferior image quality, was preferred due to its better contrast. In the 1950s, when effective anti-reflective lens coatings became available, coated Planars were produced with much-improved flare resistance. These lenses used the Zeiss T coating system, which had been invented by Olexander Smakula in 1935. They performed very well as normal and medium-long focus lenses for small and medium format cameras. One of the most notable Planar lenses is the high-speed 2.0/110 mm lens for the 2000- and 200-series medium format Hasselblad cameras. See also * Carl Zeiss Planar 50mm f/0.7 * *Tessar * Sonnar *Biogon * * *Hologon *Photographic l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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