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Line 14: − ===Shutter=== − Within the camera is a device called the shutter, which is a light-tight, mechanically movable element which lies in front of the film or electronic sensor. When the photographer takes the picture the shutter opens, allowing light to hit the film or sensor for the duration of the preset shutter speed. After exposure, the shutter closes and protects the film or sensor from unwanted light, and will open again during the photographer's next attempt. − − Compact, medium format and large format cameras usually have a central, or leaf, shutter with resilient curved slats that open radially for the duration of the exposure. The central shutter can be located in the camera body or inside the lens between the front and rear lens groups. In film-based cameras such as SLRs the focal plane shutter is located in the camera immediately in front of the film plane in the housing. For exposure, it opens similar to a double-curtain in some models or creates a slot in others; both have variable width which is determined by the exposure time. The longer the exposure time, the wider the slot. Some single-lens medium-format SLRs with central shutter lenses also have an additional focal plane shutter which is not meant for image exposure, but only as an aid or auxiliary closure to protect the film from light when focusing or changing a lens. − − In the early days of photography exposure times of several minutes, but at least several seconds were required, with the "shutter" simply being the lens cap removed and replaced by the photographer during the exposure time. Prior to the advent of digital cameras, film SLRs have mechanically controlled shutter speeds up to 1/1000 second for focal plane shutters, and up to 1/500 second for the central shutter. The shortest purely mechanical shutter speed is 1/4000 second for the Nikon FM2 of 1982-2001. Longer shutter speeds in the low second range can be found in older cameras with the self-timer mechanism. With electronic shutter control by means of electromagnets and control electronics, modern 35 mm cameras achieve the shortest shutter speeds of 1/12,000 second (Minolta Dynax 9xi and Dynax 9) and system cameras (Olympus OM-D E-M1 Mark II) even of 1/32000, but also automatically controlled times up to 30 seconds and longer are feasible. − − + − + − + − + + + + + + + + + + + + +
→Parts of a camera
==Parts of a camera==
==Parts of a camera==
===Lens===
===Lens===
The image-forming device that is the main portion of a camera is the lens, and depending on the camera consists of one to as many as 12 elements. The first cameras were fitted with a single lens consisting of one convex and one concave surface, called a ''meniscus'' lens; as camera design improved, so did the lens, and the single lens element was placed within inexpensive pocket cameras where it did produce satisfactory results for amateur photographers.
The image-forming device that is the main portion of a camera is the lens, and depending on the camera consists of one to as many as 12 elements. The first cameras were fitted with a single lens consisting of one convex and one concave surface, called a ''meniscus'' lens; as camera design improved, so did the lens, and the single lens element was placed within inexpensive pocket cameras where it did produce satisfactory results for amateur photographers. The power of the lens is indicated by the F-number, referred to as the ''aperture'', and is controlled by a series of F-stops which opens or closes a diaphragm within the lens. The speed, or light-gathering power, of the lens is determined by the F-stops, with the smallest number (F/2.0 on many lenses) allowing the greatest amount of light to reach the film or sensor when the shutter is snapped.
The three basic types of lenses which evolved beginning in the early-20th century were wide-angle, normal, and telephoto.
The three basic types of lenses which evolved beginning in the early-20th century were wide-angle, normal, and telephoto.
====Wide-angle====
====Wide-angle====
Wide-angle lenses are used to present as wide as possible the image being taken, such as getting a famous bridge in one shot for illustrative purposes, or to photograph the interior of a house for sale. Such lenses are also categorized into three types: "fisheye", ultra-wide and simple wide-angle. "Fisheye" photographic lenses cover an angle of 180° and greater, while the deformation they create is excessive. The ultra-wide-angle photographic lenses have a viewing angle of from about 100° to about 85°, the deformation they cause is easier to control than "fisheye". Wide-angle photographic lenses have a viewing angle of approximately 90° to 60°, their distortion being small, approaching the perspective found in normal lenses.
Wide-angle lenses are used to present as wide as possible the image being taken, or where there is a limited amount of distance between the camera and the subject, such as getting a famous bridge in one shot for illustrative purposes, or to photograph the interior of a house for sale. Such lenses are also categorized into three types: "fisheye", ultra-wide and simple wide-angle. "Fisheye" photographic lenses cover an angle of 180° and greater, while the deformation they create is excessive; it gives the finished images a deeply-curved look, hence the name. The ultra-wide-angle photographic lenses have a viewing angle of from about 100° to about 85°, the deformation they cause is easier to control than "fisheye". Wide-angle photographic lenses have a viewing angle of approximately 90° to 60°, their distortion being small, approaching the perspective found in normal lenses.
====Normal====
====Normal====
Normal lenses have a viewing angle of approximately 55° to 35°. These lenses are the most common and are particularly useful for generic photos and photos under low light as they have a large aperture.
Normal lenses have a viewing angle of approximately 55° to 35°. These lenses are the most common and are particularly useful for generic photos and photos under low light as they have a large aperture. The "normal" part of the name is from the subject within the image, as the person or object appears normal in size and shape, relative to the background.
====Telephoto====
====Telephoto====
Telephoto lenses are used primarily to bring into focus an object which is otherwise unobtainable due to distance, such as a faraway building or wildlife. They have a viewing angle of 40° to 1°.
Telephoto, or long-focus, lenses are used primarily to bring into focus an object which is otherwise unobtainable due to distance, such as a faraway building or wildlife, and show an enlarged detail over the same area versus a normal lens. They have a viewing angle of 40° to 1°. Telephoto lenses are often large, necessitating the use of a tripod for control.
Mirror lenses are a recent addition to the telephoto category. Barrel-shaped and light due to the inclusion of mirrors, they are essentially a hand-held Cassegrain telescope. The advantages they have over standard lenses are less cost and similar, if not greater, image-gathering ability; their fixed F-stop (F/6 to F/8) limits their use to daylight hours.
===Shutter===
Within the camera is a device called the shutter, which is a light-tight, mechanically movable element which lies in front of the film or electronic sensor. When the photographer takes the picture the shutter opens, allowing light to hit the film or sensor for the duration of the preset shutter speed. After exposure, the shutter closes and protects the film or sensor from unwanted light, and will open again during the photographer's next attempt.
Compact, medium format and large format cameras usually have a central, or leaf, shutter with resilient curved slats that open radially for the duration of the exposure. The central shutter can be located in the camera body or inside the lens between the front and rear lens groups. In film-based cameras such as SLRs the focal plane shutter is located in the camera immediately in front of the film plane in the housing. For exposure, it opens similar to a double-curtain in some models or creates a slot in others; both have variable width which is determined by the exposure time. The longer the exposure time, the wider the slot. Some single-lens medium-format SLRs with central shutter lenses also have an additional focal plane shutter which is not meant for image exposure, but only as an aid or auxiliary closure to protect the film from light when focusing or changing a lens.
In the early days of photography exposure times of several minutes, but at least several seconds were required, with the "shutter" simply being the lens cap removed and replaced by the photographer during the exposure time. Prior to the advent of digital cameras, film SLRs have mechanically controlled shutter speeds up to 1/1000 second for focal plane shutters, and up to 1/500 second for the central shutter. The shortest purely mechanical shutter speed is 1/4000 second for the Nikon FM2 of 1982-2001. Longer shutter speeds in the low second range can be found in older cameras with the self-timer mechanism. With electronic shutter control by means of electromagnets and control electronics, modern 35 mm cameras achieve the shortest shutter speeds of 1/12,000 second (Minolta Dynax 9xi and Dynax 9) and system cameras (Olympus OM-D E-M1 Mark II) even of 1/32000, but also automatically controlled times up to 30 seconds and longer are feasible.
===Viewfinder===
The photographer views the composition and focuses on the image via a viewfinder, which may be optical or electronic. In the optical version the viewfinder is either a separate entity from the lens (such as pocket cameras) or is visually connected through the lens (as in SLRs). The electronic viewfinder is a product of modern digital cameras; the image seen through the lens is focused on an LCD or OLED screen fixed to the back of the camera, which has the added benefit of allowing the photographer to hold the camera at arm's length while taking the shot.
==Types of cameras==
==Types of cameras==