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Canon EF Camera
The Canon EF is a manual focus 35mm single-lens reflex camera produced by Canon between 1973 and 1978. It was compatible with Canon's FD-mount lenses. The EF was built as an electro-mechanical version of Canon's top-of-the line wholly mechanical Canon F-1. The shutter is mechanical at all speeds starting at 1/2 second and faster, but from 1 second and beyond the shutter is all electric, allowing for AE shutter speeds as long as 30 seconds. The EF shares the F-1's rugged construction and tough metal body. Unlike the F-1, the EF does not support any motor drive for film transport. Neither does it provide any interchangeable viewfinder. The Canon EF contained a silicon photocell light meter with a range of EV 18 to EV -2 which measured light in a "central emphasis metering" pattern (also called center weighted average metering) with less influence from the top of the frame, to minimize underexposure due to a bright skyline. Note that this requires the camera to be held horizon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisheye Lens
A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. Fisheye lenses achieve extremely wide angles of view, well beyond any rectilinear lens. Instead of producing images with straight lines of perspective ( rectilinear images), fisheye lenses use a special mapping ("distortion"; for example: equisolid angle, see below), which gives images a characteristic convex non-rectilinear appearance. The term ''fisheye'' was coined in 1906 by American physicist and inventor Robert W. Wood based on how a fish would see an ultrawide hemispherical view from beneath the water (a phenomenon known as Snell's window). Their first practical use was in the 1920s for use in meteorology to study cloud formation giving them the name "whole-sky lenses". The angle of view of a fisheye lens is usually between 100 and 180 degrees, although lenses covering up to 280 degrees exist (see below). Their focal lengths d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shutter Speed
In photography, shutter speed or exposure time is the length of time that the film or digital sensor inside the camera is exposed to light (that is, when the camera's shutter is open) when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time. of a second will let half as much light in as . Introduction The camera's shutter speed, the lens's aperture or f-stop, and the scene's luminance together determine the amount of light that reaches the film or sensor (the exposure). Exposure value (EV) is a quantity that accounts for the shutter speed and the f-number. Once the sensitivity to light of the recording surface (either film or sensor) is set in numbers expressed in " ISOs" (ex: 200 ISO, 400 ISO), the light emitted by the scene photographed can be controlled through aperture and shutter-speed to match the film or sensor sensitivity to light. This will achieve a good exposure when all the details of the sce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (electricity)
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver and was formerly named hydrargyrum ( ) from the Greek words, ''hydor'' (water) and ''argyros'' (silver). A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. Mercury occurs in deposits throughout the world mostly as cinnabar ( mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definition One volt is defined as the electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units ( m, kg, s, and A) as : \text = \frac = \frac = \frac. It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per current), or joules per coulomb (energy per charge), which is also equivalent to electronvolts per elementary charge: : \text = \text\Omega = \fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focusing Screen
A focusing screen is a flat translucent material, either a ground glass or Fresnel lens, found in a system camera that allows the user of the camera to preview the framed image in a viewfinder In photography, a viewfinder is what the photographer looks through to compose, and, in many cases, to focus the picture. Most viewfinders are separate, and suffer parallax, while the single-lens reflex camera lets the viewfinder use the main .... Often, focusing screens are available in variants with different etched markings for various purposes. For instance, "overall matte" focusing screens with no etchings are a popular choice for astrophotography and other low-light situations. Overview The history of the focusing screen is almost as long as the history of the camera. Some primitive cameras consisted of a box with a board holding the lens in the front and a focusing screen in the back that was replaced by the imaging medium (plate, film holder) before taking the picture. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon Ef Finder
Canon or Canons may refer to: Arts and entertainment * Canon (fiction), the conceptual material accepted as official in a fictional universe by its fan base * Literary canon, an accepted body of works considered as high culture ** Western canon, the body of high culture literature, music, philosophy, and works of art that is highly valued in the West * Canon of proportions, a formally codified set of criteria deemed mandatory for a particular artistic style of figurative art * Canon (music), a type of composition * Canon (hymnography), a type of hymn used in Eastern Orthodox Christianity. * ''Canon'' (album), a 2007 album by Ani DiFranco * ''Canon'' (film), a 1964 Canadian animated short * ''Canon'' (game), an online browser-based strategy war game * ''Canon'' (manga), by Nikki * Canonical plays of William Shakespeare * ''The Canon'' (Natalie Angier book), a 2007 science book by Natalie Angier * ''The Canon'' (podcast), concerning film Brands and enterprises * Cano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Plane Shutter
In camera design, a focal-plane shutter (FPS) is a type of photographic shutter that is positioned immediately in front of the focal plane of the camera, that is, right in front of the photographic film or image sensor. Two-curtain shutters The traditional type of focal-plane shutter in 35 mm cameras, pioneered by Leitz for use in its Leica cameras, uses two shutter curtains, made of opaque rubberised fabric, that run horizontally across the film plane. For slower shutter speeds, the first curtain opens (usually) from right to left, and after the required time with the shutter open, the second curtain closes the aperture in the same direction. When the shutter is cocked again the shutter curtains are moved back to their starting positions, ready to be released. Focal-plane shutter at low speed ''Figure 1:'' The black rectangle represents the frame aperture through which the exposure is made. It is currently covered by the first shutter curtain, shown in red. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copal (company)
The , or Copal, is a Japanese manufacturer of optical, electronic and mechanical equipment, primarily for the photographic industry. It has been a subsidiary of Nidec Corporation since 1998, and was formerly known as the Copal Corporation. The company began operation in 1946, with small-scale production of photographic shutters; these are still one of the company's best-known products. In the 1960s the company began producing the well-known Copal Square vertically travelling metal blade focal plane shutter, which was very successful and was used in cameras by many prominent manufacturers. The ''Copal Square-S'', for example used in the Konica T3s (1973-1978) and the Nikkormat FT, is very reliable. It works over a wide temperature range. The electronically controlled Copal ''Square E'' (1968) was used in the Yashica TL Electro X, the Canon EF, the Nikkormat EL. For Minolta XE and the Leica R3 the Copal-Leitz Shutter ''CLS'' was developed in 1972. For the professional Nikon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF Top
Canon or Canons may refer to: Arts and entertainment * Canon (fiction), the conceptual material accepted as official in a fictional universe by its fan base * Literary canon, an accepted body of works considered as high culture ** Western canon, the body of high culture literature, music, philosophy, and works of art that is highly valued in the West * Canon of proportions, a formally codified set of criteria deemed mandatory for a particular artistic style of figurative art * Canon (music), a type of composition * Canon (hymnography), a type of hymn used in Eastern Orthodox Christianity. * ''Canon'' (album), a 2007 album by Ani DiFranco * ''Canon'' (film), a 1964 Canadian animated short * ''Canon'' (game), an online browser-based strategy war game * ''Canon'' (manga), by Nikki * Canonical plays of William Shakespeare * ''The Canon'' (Natalie Angier book), a 2007 science book by Natalie Angier * ''The Canon'' (podcast), concerning film Brands and enterprises * Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon R
The Canon R lens mount is a physical standard for connecting a camera lens to a 35mm single-lens reflex camera body. It was introduced in March 1959 along with the Canon Canonflex. The R mount was used on Canon's first single lens reflex (SLR) camera. The mount employed a "breech lock" system to attach the lens to the camera body. The R mount was discontinued in 1964 and replaced with the Canon FL lens mount. Many mirrorless interchangeable-lens cameras are able to use Canon R lenses via an adapter. The mechanism for controlling the aperture is different from both the later FL and FD mount, although they physically still can mate with most adapters. R cameras * Canon Canonflex The Canonflex is a Canon 35 mm film single-lens reflex (SLR) camera introduced in May 1959. Its standard lens is the ''Canon Camera Co. Super-Canomatic R 50mm lens 1.8''. The camera was in production for one year before it was replaced by the Can ... (1959) * Canon Canonflex R2000 (1960) * Cano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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