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Canon AF35M
The Canon AF35M, by Canon Japan or the Sure Shot by Canon USA, was Canon Inc.'s first autofocus 135 film, 35mm lens-shutter Point-and-shoot camera, compact camera. It was launched in November 1979 and received the Japanese Ministry of International Trade and Industry's 1980 Good Design Award in September 1980. It proved successful among similar cameras from the competition and sold well; production reached 110,000 per month by the second half of 1981. It was partly supplanted by 1981's higher-specified Canon AF35ML, AF35ML and wholly replaced by 1983's Canon AF35M II, AF35M II. The active autofocus system used a light-emitting diode, near-infrared emitting diode and a PIN photodiode to determine the subject position by triangulation in a manner similar to a coincident-image rangefinder. This meant that the system was independent of ambient light levels and achieved a high degree of accuracy; however, it could be fooled by glass (which is not transparent to infrared radiati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon AF35M
The Canon AF35M, by Canon Japan or the Sure Shot by Canon USA, was Canon Inc.'s first autofocus 135 film, 35mm lens-shutter Point-and-shoot camera, compact camera. It was launched in November 1979 and received the Japanese Ministry of International Trade and Industry's 1980 Good Design Award in September 1980. It proved successful among similar cameras from the competition and sold well; production reached 110,000 per month by the second half of 1981. It was partly supplanted by 1981's higher-specified Canon AF35ML, AF35ML and wholly replaced by 1983's Canon AF35M II, AF35M II. The active autofocus system used a light-emitting diode, near-infrared emitting diode and a PIN photodiode to determine the subject position by triangulation in a manner similar to a coincident-image rangefinder. This meant that the system was independent of ambient light levels and achieved a high degree of accuracy; however, it could be fooled by glass (which is not transparent to infrared radiati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle measurements at known points, rather than measuring distances to the point directly as in trilateration; the use of both angles and distance measurements is referred to as triangulateration. In computer vision Computer stereo vision and optical 3D measuring systems use this principle to determine the spatial dimensions and the geometry of an item. Basically, the configuration consists of two sensors observing the item. One of the sensors is typically a digital camera device, and the other one can also be a camera or a light projector. The projection centers of the sensors and the considered point on the object's surface define a (spatial) triangle. Within this triangle, the distance between the sensors is the base ''b'' and must be known. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guide Number
When setting photoflash exposures, the guide number (GN) of photoflash devices (flashbulbs and electronic devices known as "studio strobes", "on-camera flashes", "electronic flashes", "flashes", and "speedlights")The Nikon brand name for its camera-mounted electronic flash products, ''Speedlight'', is frequently used in lowercase form (''speedlight'' ) as a generic term for hot shoe-mounted electronic flash devices while Canon uses the trade name ''Speedlite''. is a measure photographers can use to calculate either the required fstop for any given flash-to-subject distance, or the required distance for any given fstop. To solve for either of these two variables, one merely divides a device's guide number by the other. Though guide numbers are influenced by a variety of variables, their values are presented as the product of only two factors as follows: ::Guide number = f-number × distance This simple inverse relationship holds true because the brightness of a flash decl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Ring
In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a glass or plastic disk in a metal or plastic ring frame, which can be screwed into the front of or clipped onto the camera lens. Filters modify the images recorded. Sometimes they are used to make only subtle changes to images; other times the image would simply not be possible without them. In monochrome photography, coloured filters affect the relative brightness of different colours; red lipstick may be rendered as anything from almost white to almost black with different filters. Others change the colour balance of images, so that photographs under incandescent lighting show colours as they are perceived, rather than with a reddish tinge. There are filters that distort the image in a desired way, diffusing an otherwise sharp image, addin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Meter
A light meter is a device used to measure the amount of light. In photography, a light meter (more correctly an exposure meter) is used to determine the proper exposure for a photograph. The meter will include either a digital or analog calculator which displays the correct shutter speed and f-number for optimum exposure, given a certain lighting situation and film speed. Similarly, exposure meters are also used in the fields of cinematography and scenic design, in order to determine the optimum light level for a scene. Light meters are used in the general field of architectural lighting design to verify proper installation and performance of a building lighting system, and in assessing the light levels for growing plants. Use in photography The earliest type of light meters were called ''extinction meters'' and contained a numbered or lettered row of neutral density filters of increasing density. The photographer would position the meter in front of his subject and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadmium Sulfide
Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare minerals greenockite and hawleyite, but is more prevalent as an impurity substituent in the similarly structured zinc ores sphalerite and wurtzite, which are the major economic sources of cadmium. As a compound that is easy to isolate and purify, it is the principal source of cadmium for all commercial applications. Its vivid yellow color led to its adoption as a pigment for the yellow paint "cadmium yellow" in the 18th century. Production Cadmium sulfide can be prepared by the precipitation from soluble cadmium(II) salts with sulfide ion. This reaction has been used for gravimetric analysis and qualitative inorganic analysis.The preparative route and the subsequent treatment of the product, affects the polymorphic form that is produced ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film Speed
Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to describe the relationship between exposure and output image lightness in digital cameras. Relatively insensitive film, with a correspondingly lower speed index, requires more exposure to light to produce the same image density as a more sensitive film, and is thus commonly termed a ''slow film''. Highly sensitive films are correspondingly termed ''fast films''. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise of other types). In short, the higher the sensitivity, the grainier the image will be. Ultimately sensitivity is limited by the quantum efficiency of the film or sensor. Film speed measurement systems His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An optical system typically has many openings or structures that limit the ray bundles (ray bundles are also known as ''pencils'' of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that primarily determines the ray cone angle and brightness at the image point. In some contexts, especially in photography and astronomy, ''aperture'' refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope, the aperture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower opti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 optical system. Viewfinders are used in many cameras of different types: still and movie, film, analog and digital. A zoom camera usually zooms its finder in sync with its lens, one exception being rangefinder cameras. History Before the development of microelectronics and electronic display devices, only optical viewfinders existed. Direct optical viewfinders Direct viewfinders are essentially miniature Galilean telescopes; the viewer's eye was placed at the back, and the scene viewed through the viewfinder optics. A declining minority of point and shoot cameras use them. Parallax error results from the viewfinder being offset from the lens axis, to point above and usually to one side of the lens. The error varies with distance, being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangefinder
A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography and in the military. They were specially useful for finding the range of a target, such as in naval gunnery and anti-aircraft artillery. The word ''telemeter'' is derived . Designs The first rangefinder telemeter was invented by James Watt in 1769 and put to use in 1771 in surveying canals. Watt called his instrument a micrometer, a term now used with a different meaning in engineering (the micrometer screw gauge). It consisted of two parallel hairs in the focal plane of a telescope eyepiece crossing an upright hair. At the point to be measured, two sliding targets on a surveyor's rod were adjusted to align with the hairs in the telescope. The distance to the rod could then be determined from the distance between the targets on the ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photodiode
A photodiode is a light-sensitive semiconductor diode. It produces current when it absorbs photons. The package of a photodiode allows light (or infrared or ultraviolet radiation, or X-rays) to reach the sensitive part of the device. The package may include lenses or optical filters. Devices designed for use specially as a photodiode use a PIN junction rather than a p–n junction, to increase the speed of response. Photodiodes usually have a slower response time as their surface area increases. A photodiode is designed to operate in reverse bias. A solar cell used to generate electric solar power is a large area photodiode. Photodiodes are used in scientific and industrial instruments to measure light intensity, either for its own sake or as a measure of some other property (density of smoke, for example). A photodiode can be used as the receiver of data encoded on an infrared beam, as in household remote controls. Photodiodes can be used to form an optocoupler, allowing tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
