Canon EF Lens Mount
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Canon EF Lens Mount
The EF lens mount is the standard lens mount on the Canon EOS family of SLR film and digital cameras. EF stands for "Electro-Focus": automatic focusing on EF lenses is handled by a dedicated electric motor built into the lens. Mechanically, it is a bayonet-style mount, and all communication between camera and lens takes place through electrical contacts; there are no mechanical levers or plungers. The mount was first introduced in 1987. Canon claims to have produced its 100-millionth EF-series interchangeable lens on 22 April 2014. History The EF mount replaces its predecessor, the FD mount. The standard autofocus lens mounting technology of the time used a motor in the camera body to drive the mechanics of the focus helicoid in the lens by using a transfer lever. The key innovation of the EF series was to use a motor inside the lens itself for focusing. This allowed for autofocusing lenses which did not require mechanical levers in the mount mechanism, only electrical con ...
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Lens Mount
A lens mount is an interface – mechanical and often also electrical – between a photographic camera body and a lens. It is a feature of camera systems where the body allows interchangeable lenses, most usually the rangefinder camera, single lens reflex type, single lens mirrorless type or any movie camera of 16 mm or higher gauge. Lens mounts are also used to connect optical components in instrumentation that may not involve a camera, such as the modular components used in optical laboratory prototyping which join via C-mount or T-mount elements. Mount types A lens mount may be a screw-threaded type, a bayonet-type, or a breech-lock (friction lock) type. Modern still camera lens mounts are of the bayonet type, because the bayonet mechanism precisely aligns mechanical and electrical features between lens and body. Screw-threaded mounts are fragile and do not align the lens in a reliable rotational position, yet types such as the C-mount interface are still widely in us ...
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Canon EF-S Lens Mount
The Canon EF-S lens mount is a derivative of the EF lens mount created for a subset of Canon digital single-lens reflex cameras with APS-C sized image sensors. It was released in 2003. Cameras with the EF-S mount are backward compatible with the EF lenses and, as such, have a flange focal distance of 44.0 mm. Such cameras, however, have more clearance, allowing lens elements to be closer to the sensor than in the EF mount. Only Canon cameras released after 2003 with APS-C sized sensors support the EF-S mount. The "S" in EF-S has variously been described by Canon as coming from either "Small image circle" (the lens projects a smaller image circle than normal EF lenses to match the sensor), or "Short back focus" (the smaller mirror used in APS-C cameras also allows optical elements to protrude further into the camera body, reducing the minimum distance between the sensor and the back element of the lens). The combination of a smaller sensor and shorter back focal length distanc ...
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Reverse Engineered
Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accomplishes a task with very little (if any) insight into exactly how it does so. It is essentially the process of opening up or dissecting a system to see how it works, in order to duplicate or enhance it. Depending on the system under consideration and the technologies employed, the knowledge gained during reverse engineering can help with repurposing obsolete objects, doing security analysis, or learning how something works. Although the process is specific to the object on which it is being performed, all reverse engineering processes consist of three basic steps: Information extraction, Modeling, and Review. Information extraction refers to the practice of gathering all relevant information for performing the operation. Modeling refers to th ...
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Carl Zeiss AG
Carl Zeiss AG (), branded as ZEISS, is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe (joined 1866) and Otto Schott (joined 1884) he laid the foundation for today's multi-national company. The current company emerged from a reunification of Carl Zeiss companies in East and West Germany with a consolidation phase in the 1990s. ZEISS is active in four business segments with approximately equal revenue (Industrial Quality and Research, Medical Technology, Consumer Markets and Semiconductor Manufacturing Technology) in almost 50 countries, has 30 production sites and around 25 development sites worldwide. Carl Zeiss AG is the holding of all subsidiaries within Zeiss Group, of which Carl Zeiss Meditec AG is the only one that is traded at the stock market. Carl Zeiss AG is owned by the foundation Carl-Zeiss-Stiftung. The Zeiss Group has its headquarters in southern Germany, in the smal ...
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Tokina
is a Japanese manufacturer of photographic lenses and CCTV security equipment. Lens designations * FX - Full frame * DX - cropped digital * AF - Auto-Focus * AT-X Pro - professional line (constant aperture zooms or primes) * AT-X - consumer line * IF - Internal Focus System * FE - Floating Element System * NH - No Hood (10-17mm fisheye without built-in hood) Optical design: * AS - Aspherical Optics * F&R - Advanced Aspherical Optics * SD - Super Low Dispersion * HLD - High-Refraction and Low Dispersion * MC - Multi-Coating Lenses Zoom * AT-X 107 DX AF fisheye 10-17mm 3.5~4.5 (available with and without the built-in hood. No hood version can be used on full-frame. The lens is also sold under Pentax brand.) * AT-X 116 PRO DX AF 11–16mm 2.8 * AT-X PRO SD 11–20mm 2.8 (IF) DX * AT-X 124 PRO DX AF 12–24mm 4 ( The lens is also sold under Pentax brand) * AT-X 124 PRO DX II SD IF AF 12–24mm 4 * AT-X PRO DX AF 12-28mm 4 * AT-X PRO FX AF 16-28mm 2.8 * AT-X 165 PRO DX AF 16–5 ...
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Tamron
is a Japanese company manufacturing photographic lenses, optical components and commercial/industrial-use optics. Tamron Headquarters is located in Saitama City in the Saitama Prefecture of Japan. The name of the company came from the surname of Uhyoue Tamura who was instrumental in developing Tamron's optical technologies. It was only on the company's 20th anniversary that the name was changed to Tamron (from Taisei Optical). Sony Corporation maintains a 12.07% share hold in Tamron, making it the second-largest shareholder below New Well Co., Ltd (ニューウェル株式会社) with 18.89% (as of June 30, 2020). In the fiscal year ending 31 December 2017, net sales totaled 60.496 billion yen and operating income was 4.24 billion yen, up 79.8% from 2016. At that time, the consolidated company had 4,640 employees and five production plants: in Hirosaki, Namioka and Owani in Japan, and one in China and Viet Nam, respectively. Subsidiary companies were located in the U.S., Ge ...
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Sigma Corporation
is a Japanese company, manufacturing cameras, lenses, flashes and other photographic accessories. All Sigma products are produced in the company's own Aizu factory in Bandai, Fukushima, Japan. Although Sigma produces several camera models, the company is best known for producing high-quality lenses and other accessories that are compatible with the cameras produced by other companies. The company was founded in 1961 by Michihiro Yamaki, who was Sigma's CEO until his death at age 78 in 2012. Sigma products work with cameras from Canon, Nikon, Pentax, Sony, Olympus and Panasonic, as well as their own cameras. Sigma has also made lenses under the Quantaray name, which have been sold exclusively by Ritz Camera. Similarly, Sigma lenses were sold exclusively by the former Wolf Camera, but following the merger of Wolf and Ritz, both brands can be purchased. Sigma's digital SLRs, the SD9, SD10, SD14 and SD15, plus the latest SD1 are unusual in their use of the Foveon X3 ...
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Schneider Kreuznach
Schneider Kreuznach () is the abbreviated name of the company Jos. Schneider Optische Werke GmbH, which is sometimes also simply referred to as Schneider. They are a manufacturer of industrial and photographic optics. The company was founded on 18 January 1913 by Joseph Schneider as Optische Anstalt Jos. Schneider & Co. at Bad Kreuznach in Germany. The company changed its name to Jos. Schneider & Co., Optische Werke, Kreuznach in 1922, and to the current Jos. Schneider Optische Werke GmbH in 1998. In 2001, Schneider received an Oscar for Technical Achievement for their Super-Cinelux motion picture lenses. It is best known as manufacturers of large format lenses for view cameras, enlarger lenses, and photographic loupes. It also makes a limited amount of small- and medium-format lenses, and has at various times manufactured eyeglasses and camera rangefinders, as well as being an OEM lens maker for Kodak and Samsung digital cameras. It has supplied the lenses for various LG devi ...
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Samyang Optics
Samyang Optics is a South Korean manufacturer of camera lenses for several major brands of third-party mounts for still photography and video cameras. The company was founded in 1972 and has about 150 employees. Samyang exports to 58 countries through 39 overseas agents and distributors. Samyang products are also sold under a wide variety of different brand names. Some examples are Rokinon, Bower, Opteka, Vivitar, Phoenix and Quantaray. Products Autofocus lenses Autofocus lenses: For Canon EF Mount: * AF 14 mm 2.8 EF * AF 85 mm 1.4 EF For Canon RF Mount: * AF 14 mm 2.8 RF * AF 85 mm 1.4 RF For Sony E-Mount: * AF 14 mm 2.8 FE * AF 18 mm 2.8 FE * AF 24 mm 2.8 FE * AF 35 mm 1.4 FE * AF 35 mm 1.8 FE * AF 35 mm 2.8 FE * AF 45 mm 1.8 FE * AF 50 mm 1.4 FE * AF 75 mm 1.8 FE * AF 85 mm 1.4 FE *AF 24-70mm 2.8 FE For Nikon F Mount: * AF 14 mm 2.8 F * AF 85 mm 1.4 F Manual focus len ...
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Yongnuo
YONGNUO(永诺) is the international trademark of photographic equipment manufacturer Shenzhen Yongnuo Photographic Equipment Co.,Ltd. of Shenzhen, China. Which develops and manufactures photographic equipment, including smart camera, lenses, LED video light, flash speedlite, flash trigger, microphone, softbox, and other accessories. YONGNUO makes autofocus prime lenses for Canon、Nikon DSLR cameras, and Canon, Sony, Nikon Mirrorless camera, also make lenses for Olympus and Panasonic. Mirrorless camera As of November 2018, YONGNUO was developing an Android smartphone based mirrorless interchangeable-lens camera, with 4G connectivity. The YN450 was released just in China in 2019 using the Canon EF lens mount. In 2020 Yongnuo developed a YN450M version using the standard Micro Four Thirds system lens mount, matching the sensor. In 2021, YONGNUO launched the YN455 version, with a 20-megapixel Four Thirds sensor, prominent handgrip and tilt screen. 2022, YONGNUO released ...
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Stop-down Metering
In photography, through-the-lens metering (TTL metering) refers to a feature of cameras whereby the intensity of light reflected from the scene is measured through the photographic lens, lens; as opposed to using a separate metering window or external hand-held light meter. In some cameras various TTL metering modes can be selected. This information can then be used to set the optimal Photographic film, film or image sensor exposure (photography), exposure (Zone System, average luminance), it can also be used to control the amount of light emitted by a flash (photography), flash unit connected to the camera. Description Through-the-lens metering is most often associated with single-lens reflex camera, single-lens reflex (SLR) cameras. In most film and digital SLRs, the light sensor(s) for exposure metering are incorporated into the pentaprism or pentamirror, the mechanism by which a SLR allows the viewfinder to see directly through the lens. As the mirror is flipped up, no light can ...
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Infinity Focus
In optics and photography, infinity focus is the state where a lens or other optical system forms an image of an object an infinite distance away. This corresponds to the point of focus for parallel rays. The image is formed at the focal point of the lens. In simple two lens systems such as a refractor telescope, the object at infinity forms an image at the focal point of the objective lens, which is subsequently magnified by the eyepiece. The magnification is equal to the focal length of the objective lens divided by the focal length of the eyepiece. In practice, not all photographic lenses are capable of achieving infinity focus by design. A lens used with an adapter for close-up focusing, for example, may not be able to focus to infinity. Failure of the human eye to achieve infinity focus is diagnosed as myopia. All optics are subject to manufacturing tolerances; even with perfect manufacture, optical trains experience thermal expansion. Focus mechanisms must accommodate p ...
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