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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. Often, focusing screens are available in variants with different etched markings for various purposes. For instance, when photographing landscapes, a focusing screen with a grid allows the photographer to keep the horizon straight. Modern mirrorless cameras do not need a focusing screen since they display what the image sensor sees on a flat-panel display or electronic viewfinder. 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. The most common type of focusing screen in non-autofocus 35 mm SLR cameras is the split screen and microprism r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autofocus
An autofocus (AF) optical system uses a sensor, a control system and a motor to focus on an automatically or manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished as active, passive or hybrid types. Autofocus systems rely on one or more sensors to determine correct focus. Some AF systems rely on a single sensor, while others use an array of sensors. Most modern SLR cameras use through-the-lens optical sensors, with a separate sensor array providing light metering, although the latter can be programmed to prioritize its metering to the same area as one or more of the AF sensors. Through-the-lens optical autofocusing is usually speedier and more precise than manual focus with an ordinary viewfinder, although more precise manual focus can be achieved with special accessories such as focusing magnifiers. Autofocus accur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microform
A microform is a scaled-down reproduction of a document, typically either photographic film or paper, made for the purposes of transmission, storage, reading, and printing. Microform images are commonly reduced to about 4% or of the original document size. For special purposes, greater optical reductions may be used. Three formats are common: microfilm (reels), microfiche (flat sheets), and aperture cards. Microcards, also known as "micro-opaques", a format no longer produced, were similar to microfiche, but printed on cardboard rather than photographic film. Equipment is available that accepts a data stream from a computer; this exposes film to produce images as if the stream had been sent to a line printer and the listing had been microfilmed. The process is known as computer output microfilm or computer output microfiche (COM). History Using the daguerreotype process, John Benjamin Dancer was one of the first to produce microphotographs, in 1839. He achieved a reduction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
:en:Edixa Reflex
The Edixa Reflex cameras, introduced in 1954, were West Germany's most popular own series of SLR's with focal plane shutter. The original name of the first Edixa SLR was Komet. The Wirgin company had to change the name after complaints of two other companies with equally named products. Since 1955 the cameras got additional slow shutter speeds, and since 1956 cameras with aperture release shifter for the M42 lenses were available. Until 1959 four lines of Edixa SLRs were introduced: *Type A, with shutter speeds up to 1/1000 sec. *Type B, with aperture release mechanics *Type C, with meter *Type D, with exposure times up to 9 sec. In 1960 the types B, C and D got the rapid mirror and improved shutter mechanics. Type A was replaced by the type S which had a slower shutter. A special feature of this camera series was the exchangeable viewfinder unit. A simple top-viewfinder and a pentaprism finder were available. In 1960 the Model B had a name change and became the Edixa-Mat Flex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autofocus
An autofocus (AF) optical system uses a sensor, a control system and a motor to focus on an automatically or manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished as active, passive or hybrid types. Autofocus systems rely on one or more sensors to determine correct focus. Some AF systems rely on a single sensor, while others use an array of sensors. Most modern SLR cameras use through-the-lens optical sensors, with a separate sensor array providing light metering, although the latter can be programmed to prioritize its metering to the same area as one or more of the AF sensors. Through-the-lens optical autofocusing is usually speedier and more precise than manual focus with an ordinary viewfinder, although more precise manual focus can be achieved with special accessories such as focusing magnifiers. Autofocus accur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perspective (visual)
Linear or point-projection perspective () is one of two types of graphical projection perspective in the graphic arts; the other is parallel projection. Linear perspective is an approximate representation, generally on a flat surface, of an image as it is seen by the eye. Perspective drawing is useful for representing a three-dimensional scene in a two-dimensional medium, like paper. It is based on the optical fact that for a person an object looks N times (linearly) smaller if it has been moved N times further from the eye than the original distance was. The most characteristic features of linear perspective are that objects appear smaller as their distance from the observer increases, and that they are subject to , meaning that an object's dimensions parallel to the line of sight appear shorter than its dimensions perpendicular to the line of sight. All objects will recede to points in the distance, usually along the horizon line, but also above and below the horizon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangefinder Camera
A rangefinder camera is a camera fitted with a rangefinder, typically a split-image rangefinder: a range-finding focusing mechanism allowing the photographer to measure the subject distance and take photographs that are in sharp focus. Most varieties of rangefinder show two images of the same subject, one of which moves when a calibrated wheel is turned; when the two images coincide and fuse into one, the distance can be read off the wheel. Older, non-coupled rangefinder cameras display the focusing distance and require the photographer to transfer the value to the lens focus ring; cameras without built-in rangefinders could have an external rangefinder fitted into the accessory shoe. Earlier cameras of this type had separate viewfinder and rangefinder windows; later the rangefinder was incorporated into the viewfinder. More modern designs have rangefinders coupled to the focusing mechanism so that the lens is focused correctly when the rangefinder images fuse; compare with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Lens Reflex
In photography, a single-lens reflex camera (SLR) is a type of camera that uses a mirror and prism system to allow photographers to view through the lens and see exactly what will be captured. SLRs became the dominant design for professional and consumer-level cameras throughout the late 20th century, offering interchangeable lenses, through-the-lens (TTL) metering, and precise framing. Originating in the 1930s and popularized in the 1960s and 70s, SLR technology played a crucial role in the evolution of modern photography. Although digital single-lens reflex (DSLR) cameras succeeded film-based models, the rise of mirrorless cameras in the 2010s has led to a decline in SLR use and production. 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 and allows light to pass through to the light receptor and the image to be captured. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Viewfinder
An electronic viewfinder (EVF) is a camera viewfinder where the image captured by the lens is displayed on a small screen (usually LCD or OLED) which the photographer can look through when composing their shot. It differs from a live preview screen in being smaller and shaded from ambient light, and may also use less power. The sensor records the view through the lens, the view is processed, and finally projected on a miniature display which is viewable through the eyepiece. Digital viewfinders are used in digital still cameras and in video cameras. Some cameras (such as Panasonic, Sony, Fujifilm) have an automatic eye sensor which switches the display from screen to EVF when the viewfinder is near the eye. More modest cameras use a button to switch the display. Some have no button at all. While many cameras come with a built-in EVF, this is fixed in place and can only be used while holding the camera to the user's eye, which may not be convenient. Other cameras don't come with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLR Cross Section
SLR may refer to: Science and technology * Satellite laser ranging, a method to measure the distance to satellites * Scalable Linear Recording tape drive backup * Scanline rendering * Sea level rise * Self-loading rifle or Semi-automatic rifle#Operation, semi-automatic rifle ** The UK L1A1 SLR rifle * Semi-linear resolution, a search algorithm * Sending loudness rating for microphones * Service List Registry, of audiovisual services * Simple linear regression, a method of statistical modeling * Simple LR parser (simple left-to-right parser), a method of syntax analysis * Single-lens reflex camera ** See also: Digital single-lens reflex camera (digital SLR or DSLR) * SLR (company), a virtual reality company * Systematic literature review (see also Systematic review), a type of academic text Transport * Holden Torana#A9X option, Holden Torana SLR5000 car * Mercedes-Benz 300 SLR * Mercedes-Benz SLR McLaren * Shimano#Shimano products, Shimano Linear Response, a bicycle component * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat-panel Display
A flat-panel display (FPD) is an electronic visual display, electronic display used to display device, display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment. Flat-panel displays are thin, lightweight, provide better linearity and are capable of higher resolution than typical consumer-grade TVs from earlier eras. They are usually less than thick. While the highest resolution for consumer-grade Cathode-ray tube, CRT televisions was 1080i, many interactive flat panels in the 2020s are capable of 1080p and 4K UHD, 4K resolution. In the 2010s, portable consumer electronics such as laptops, mobile phones, and portable cameras have used flat-panel displays since they consume less power and are lightweight. As of 2016, flat-panel displays have almost completely replaced CRT displays. Most 2010s-era flat-panel displays use LCD or light-emitting diode (LED) technologies, sometimes combined. Most LCD screens are Backl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image Sensor
An image sensor or imager is a sensor that detects and conveys information used to form an image. It does so by converting the variable attenuation of light waves (as they refraction, pass through or reflection (physics), reflect off objects) into signal (electrical engineering), signals, small bursts of electric current, current that convey the information. The waves can be light or other electromagnetic radiation. Image sensors are used in electronics, electronic imaging devices of both analogue electronics, analog and digital electronics, digital types, which include digital cameras, camera modules, camera phones, optical mouse devices, medical imaging equipment, night vision equipment such as thermography, thermal imaging devices, radar, sonar, and others. As technological change, technology changes, electronic and digital imaging tends to replace chemical and analog imaging. The two main types of electronic image sensors are the charge-coupled device (CCD) and the active-pixel s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
