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121-442: Through-the-lens metering is most often associated with 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 reach there during exposure, the necessary amount of exposure needs to be determined before

242-412: A CMOS or CCD chip, used to collect the light, is not reflective enough. There are a few older digital cameras which still use the analog technique, but these are getting rare. The Fujifilm S1 and S3 are the most well known digital cameras to use this technique. Digital TTL works as follows: Before the actual exposure one or more small flashes, called "preflashes", are emitted. The light returning through

363-604: A DSLR model, the Contax N-Digital . This model was too late and too expensive to be competitive with other camera manufacturers. The Contax N-digital was the last Contax to use that maker's lens system, and the camera, while having impressive features such as a full-frame sensor, was expensive and lacked sufficient write-speed to the memory card for it to be seriously considered by some professional photographers. The digital single-lens reflex camera have largely replaced film SLRs design in convenience, sales and popularity at

484-538: A DSLR model, the Contax N-Digital . This model was too late and too expensive to be competitive with other camera manufacturers. The Contax N-digital was the last Contax to use that maker's lens system, and the camera, while having impressive features such as a full-frame sensor, was expensive and lacked sufficient write-speed to the memory card for it to be seriously considered by some professional photographers. The digital single-lens reflex camera have largely replaced film SLRs design in convenience, sales and popularity at

605-462: A black surface and could not be used in TTL flash mode. Nevertheless, for most applications analogue TTL flash exposure metering was more advanced and accurate than systems used previously and permitted far more flexibility - with bounced flash exposures in particular being more accurate than manually calculated equivalents. With digital, this way of direct reflection metering is not possible any more since

726-482: A dedicated system, once the dedicated electronic flash is inserted into the camera's hot shoe and turned on, there is then communication between camera and flash. The camera's synchronization speed is set, along with the aperture. Many camera models measure the light that reflects off of the film plane, which controls the flash duration of the electronic flash. This is denoted TTL flash metering . Some electronic flash units can send out several short bursts of light to aid

847-482: A dedicated system, once the dedicated electronic flash is inserted into the camera's hot shoe and turned on, there is then communication between camera and flash. The camera's synchronization speed is set, along with the aperture. Many camera models measure the light that reflects off of the film plane, which controls the flash duration of the electronic flash. This is denoted TTL flash metering . Some electronic flash units can send out several short bursts of light to aid

968-457: A medium-format SLR with a between-the-lens leaf shutter system would be Hasselblad , with their 500C, 500 cm, 500 EL-M (a motorized Hasselblad) and other models (producing a 6 cm square negative). Hasselblads use an auxiliary shutter blind situated behind the lens mount and the mirror system to prevent the fogging of film. Other medium-format SLRs also using leaf shutters include the now discontinued Zenza-Bronica camera system lines such as

1089-457: A medium-format SLR with a between-the-lens leaf shutter system would be Hasselblad , with their 500C, 500 cm, 500 EL-M (a motorized Hasselblad) and other models (producing a 6 cm square negative). Hasselblads use an auxiliary shutter blind situated behind the lens mount and the mirror system to prevent the fogging of film. Other medium-format SLRs also using leaf shutters include the now discontinued Zenza-Bronica camera system lines such as

1210-409: A narrower depth of field, which is useful for blurring the background behind the subject, making the subject more prominent. "Fast" lenses are commonly used in theater photography, portrait photography, surveillance photography, and all other photography requiring a large maximum aperture. The variety of lenses also allows for the camera to be used and adapted in many different situations. This provides

1331-409: A narrower depth of field, which is useful for blurring the background behind the subject, making the subject more prominent. "Fast" lenses are commonly used in theater photography, portrait photography, surveillance photography, and all other photography requiring a large maximum aperture. The variety of lenses also allows for the camera to be used and adapted in many different situations. This provides

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1452-590: A photographer purchased one of these lenses, that lens included a leaf shutter in its lens mount. Because leaf shutters synchronized electronic flash at all shutter speeds especially at fast shutter speeds of 1 ⁄ 500 of a second or faster, cameras using leaf shutters were more desirable to studio photographers who used sophisticated studio electronic flash systems. Some manufacturers of medium-format 120 film SLR cameras also made leaf-shutter lenses for their focal-plane-shutter models. Rollei made at least two such lenses for their Rolleiflex SL-66 medium format which

1573-590: A photographer purchased one of these lenses, that lens included a leaf shutter in its lens mount. Because leaf shutters synchronized electronic flash at all shutter speeds especially at fast shutter speeds of 1 ⁄ 500 of a second or faster, cameras using leaf shutters were more desirable to studio photographers who used sophisticated studio electronic flash systems. Some manufacturers of medium-format 120 film SLR cameras also made leaf-shutter lenses for their focal-plane-shutter models. Rollei made at least two such lenses for their Rolleiflex SL-66 medium format which

1694-436: A proper exposure is still used in automatic flash modes. Crush, Darren (Spring 2012). "Budget TTL flashguns". Practical Photography . Peterborough: Bauer. pp. 118–121, 123. ISSN   0032-6445 . OCLC   749128201 . Single-lens reflex camera A single-lens reflex camera ( SLR ) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits

1815-603: A roof pentaprism or penta-mirror to direct the light to the eyepiece, first used on the 1948 Duflex constructed by Jenő Dulovits and patented August 1943 (Hungary). With this camera also appeared the first instant-return mirror . The first Japanese pentaprism SLR was the 1955 Miranda T , followed by the Asahi Pentax, Minolta SR-2, Zunow, Nikon F and the Yashica Pentamatic. Some SLRs offered removable pentaprisms with optional viewfinder capabilities, such as

1936-474: A roof pentaprism or penta-mirror to direct the light to the eyepiece, first used on the 1948 Duflex constructed by Jenő Dulovits and patented August 1943 (Hungary). With this camera also appeared the first instant-return mirror . The first Japanese pentaprism SLR was the 1955 Miranda T , followed by the Asahi Pentax, Minolta SR-2, Zunow, Nikon F and the Yashica Pentamatic. Some SLRs offered removable pentaprisms with optional viewfinder capabilities, such as

2057-419: A viewing image that will be exposed onto the negative exactly as it is seen through the lens. There is no parallax error, and exact focus can be confirmed by eye—especially in macro photography and when photographing using long focus lenses . The depth of field may be seen by stopping down to the attached lens aperture , which is possible on most SLR cameras except for the least expensive models. Because of

2178-419: A viewing image that will be exposed onto the negative exactly as it is seen through the lens. There is no parallax error, and exact focus can be confirmed by eye—especially in macro photography and when photographing using long focus lenses . The depth of field may be seen by stopping down to the attached lens aperture , which is possible on most SLR cameras except for the least expensive models. Because of

2299-402: Is available that slips onto the eyepiece of most SLRs and D-SLRs and allows viewing through a waist-level viewfinder. There is also a finder that provides EVF remote capability. Almost all contemporary SLRs use a focal-plane shutter located in front of the film plane, which prevents the light from reaching the film even if the lens is removed, except when the shutter is actually released during

2420-402: Is available that slips onto the eyepiece of most SLRs and D-SLRs and allows viewing through a waist-level viewfinder. There is also a finder that provides EVF remote capability. Almost all contemporary SLRs use a focal-plane shutter located in front of the film plane, which prevents the light from reaching the film even if the lens is removed, except when the shutter is actually released during

2541-399: Is not easy to focus the lens of a fast reflex camera when it is opened to wider apertures (such as in low light or while using low-speed film). Most SLR cameras permit upright and laterally correct viewing through use of a roof pentaprism situated in the optical path between the reflex mirror and viewfinder. Light, which comes both horizontally and vertically inverted after passing through

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2662-399: Is not easy to focus the lens of a fast reflex camera when it is opened to wider apertures (such as in low light or while using low-speed film). Most SLR cameras permit upright and laterally correct viewing through use of a roof pentaprism situated in the optical path between the reflex mirror and viewfinder. Light, which comes both horizontally and vertically inverted after passing through

2783-413: Is rarely enough room above and below the frame for a one-piece shutter. Vertical shutters became very common in the 1980s (though Konica , Mamiya , and Copal first pioneered their use in the 1950s and 1960s, and are almost exclusively used for new cameras. Nikon used Copal-made vertical plane shutters in their Nikomat/Nikkormat -range, enabling x-sync speeds from 1 ⁄ 30 to 1 ⁄ 125 while

2904-413: Is rarely enough room above and below the frame for a one-piece shutter. Vertical shutters became very common in the 1980s (though Konica , Mamiya , and Copal first pioneered their use in the 1950s and 1960s, and are almost exclusively used for new cameras. Nikon used Copal-made vertical plane shutters in their Nikomat/Nikkormat -range, enabling x-sync speeds from 1 ⁄ 30 to 1 ⁄ 125 while

3025-517: Is rated for 200,000 shutter cycles and the Nikon D3 is rated for 300,000 with its exotic carbon fiber/kevlar shutter. Because many SLRs have interchangeable lenses, there is a tendency for dust, sand and dirt to get into the main body of the camera through the mirror box when the lens is removed, thus dirtying or even jamming the mirror movement mechanism or the shutter curtain mechanism itself. In addition, these particles can also jam or otherwise hinder

3146-461: Is rated for 200,000 shutter cycles and the Nikon D3 is rated for 300,000 with its exotic carbon fiber/kevlar shutter. Because many SLRs have interchangeable lenses, there is a tendency for dust, sand and dirt to get into the main body of the camera through the mirror box when the lens is removed, thus dirtying or even jamming the mirror movement mechanism or the shutter curtain mechanism itself. In addition, these particles can also jam or otherwise hinder

3267-802: Is required. A small number of SLRs were built for APS such as the Canon IX series and the Nikon Pronea cameras. SLRs were also introduced for film formats as small as Kodak's 110 , such as the Pentax Auto 110 , which had interchangeable lenses. The Narciss camera is an all-metal 16 mm subminiature single lens reflex camera made by Russian optic firm Krasnogorsky Mekhanichesky Zavod (KMZ) Narciss (Soviet Union; Нарцисс) between 1961 and 1965. Other features found on many SLR cameras include through-the-lens (TTL) metering and sophisticated flash control referred to as "dedicated electronic flash". In

3388-626: Is required. A small number of SLRs were built for APS such as the Canon IX series and the Nikon Pronea cameras. SLRs were also introduced for film formats as small as Kodak's 110 , such as the Pentax Auto 110 , which had interchangeable lenses. The Narciss camera is an all-metal 16 mm subminiature single lens reflex camera made by Russian optic firm Krasnogorsky Mekhanichesky Zavod (KMZ) Narciss (Soviet Union; Нарцисс) between 1961 and 1965. Other features found on many SLR cameras include through-the-lens (TTL) metering and sophisticated flash control referred to as "dedicated electronic flash". In

3509-512: Is the leaf shutter , whereby the shutter is constructed of diaphragm-like blades and can be situated either between the lens or behind the lens. If the shutter is part of a lens assembly some other mechanism is required to ensure that no light reaches the film between exposures. An example of a behind-the-lens leaf shutter is found in the 35 mm SLRs produced by Kodak , with their Retina Reflex camera line; Topcon, with their Auto 100; and Kowa with their SE-R and SET-R reflexes. A primary example of

3630-512: Is the leaf shutter , whereby the shutter is constructed of diaphragm-like blades and can be situated either between the lens or behind the lens. If the shutter is part of a lens assembly some other mechanism is required to ensure that no light reaches the film between exposures. An example of a behind-the-lens leaf shutter is found in the 35 mm SLRs produced by Kodak , with their Retina Reflex camera line; Topcon, with their Auto 100; and Kowa with their SE-R and SET-R reflexes. A primary example of

3751-413: The 35 mm format as, this film format offers a variety of emulsions and film sensitivity speeds, usable image quality and a good market cost. 35 mm film comes in a variety of exposure lengths: 20 exposure, 24 exposure and 36 exposure rolls. Medium format SLRs provide a higher-quality image with a negative that can be more easily retouched than the smaller 35 mm negative, when this capability

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3872-413: The 35 mm format as, this film format offers a variety of emulsions and film sensitivity speeds, usable image quality and a good market cost. 35 mm film comes in a variety of exposure lengths: 20 exposure, 24 exposure and 36 exposure rolls. Medium format SLRs provide a higher-quality image with a negative that can be more easily retouched than the smaller 35 mm negative, when this capability

3993-668: The Nikon F , F2 , and F3 . Other focal-plane shutter designs, such as the Copal Square, travelled vertically — the shorter travelling distance of 24 millimetres (as opposed to 36 mm horizontally) meant that minimum exposure and flash synchronisation times could be reduced. These shutters are usually manufactured from metal, and use the same moving-slit principle as horizontally travelling shutters. They differ, though, in usually being formed of several slats or blades, rather than single curtains as with horizontal designs, as there

4114-557: The Nikon F , F2 , and F3 . Other focal-plane shutter designs, such as the Copal Square, travelled vertically — the shorter travelling distance of 24 millimetres (as opposed to 36 mm horizontally) meant that minimum exposure and flash synchronisation times could be reduced. These shutters are usually manufactured from metal, and use the same moving-slit principle as horizontally travelling shutters. They differ, though, in usually being formed of several slats or blades, rather than single curtains as with horizontal designs, as there

4235-479: The photographer to view through the lens and see exactly what will be captured. 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, allowing light to pass through to the light receptor and the image to be captured. Until the development of SLR, all cameras with viewfinders had two optical light paths: one through

4356-479: The photographer to view through the lens and see exactly what will be captured. 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, allowing light to pass through to the light receptor and the image to be captured. Until the development of SLR, all cameras with viewfinders had two optical light paths: one through

4477-450: The pixel resolution, contrast ratio , refresh rate , and color gamut of an LCD preview screen cannot compete with the clarity and shadow detail of a direct-viewed optical SLR viewfinder. Large format SLR cameras were probably first marketed with the introduction of C.R. Smith's Monocular Duplex (U.S., 1884). SLRs for smaller exposure formats were launched in the 1920s by several camera makers. The first 35 mm SLR available to

4598-450: The pixel resolution, contrast ratio , refresh rate , and color gamut of an LCD preview screen cannot compete with the clarity and shadow detail of a direct-viewed optical SLR viewfinder. Large format SLR cameras were probably first marketed with the introduction of C.R. Smith's Monocular Duplex (U.S., 1884). SLRs for smaller exposure formats were launched in the 1920s by several camera makers. The first 35 mm SLR available to

4719-888: The waist-level finder , the interchangeable sports finders used on the Canon F1 and F1n; the Nikon F, F2, F3, F4 and F5; and the Pentax LX. Another prism design was the porro prism system used in the Olympus Pen F , the Pen FT, the Pen FV half-frame 35 mm SLR cameras. This was later used on the Olympus EVOLT E-3x0 series, the Leica Digilux 3 and the Panasonic DMC-L1 . A right-angle finder

4840-412: The waist-level finder , the interchangeable sports finders used on the Canon F1 and F1n; the Nikon F, F2, F3, F4 and F5; and the Pentax LX. Another prism design was the porro prism system used in the Olympus Pen F , the Pen FT, the Pen FV half-frame 35 mm SLR cameras. This was later used on the Olympus EVOLT E-3x0 series, the Leica Digilux 3 and the Panasonic DMC-L1 . A right-angle finder

4961-660: The 1990s, SLR was the most advanced photographic preview system available, but the recent development and refinement of digital imaging technology with an on-camera live LCD preview screen has overshadowed SLR's popularity. Nearly all inexpensive compact digital cameras now include an LCD preview screen allowing the photographer to see what the CCD is capturing. However, SLR is still popular in high-end and professional cameras because they are system cameras with interchangeable parts, allowing customization. They also have far less shutter lag , allowing photographs to be timed more precisely. Also

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5082-611: The 1990s, SLR was the most advanced photographic preview system available, but the recent development and refinement of digital imaging technology with an on-camera live LCD preview screen has overshadowed SLR's popularity. Nearly all inexpensive compact digital cameras now include an LCD preview screen allowing the photographer to see what the CCD is capturing. However, SLR is still popular in high-end and professional cameras because they are system cameras with interchangeable parts, allowing customization. They also have far less shutter lag , allowing photographs to be timed more precisely. Also

5203-416: The 2000s. Around 2010, the mirrorless technology utilized in point and shoot cameras made the way to the interchangeable lens cameras and slowly replaced DSLR technology. As of 2022, all the major camera brands (Except Pentax) ceased development and production of DSLRs and moved on to mirrorless systems . These systems offer multiple advantages to the photographer with regards to autofocus systems as well as

5324-416: The 2000s. Around 2010, the mirrorless technology utilized in point and shoot cameras made the way to the interchangeable lens cameras and slowly replaced DSLR technology. As of 2022, all the major camera brands (Except Pentax) ceased development and production of DSLRs and moved on to mirrorless systems . These systems offer multiple advantages to the photographer with regards to autofocus systems as well as

5445-854: The Bronica ETRs, the ETRs'i (both producing a 6 × 4.5 cm. image), the SQ and the SQ-AI (producing a 6 × 6 cm image like the Hasselblad), and the Zenza-Bronica G system (6 × 7 cm). Certain Mamiya medium-format SLRs, discontinued camera systems such as the Kowa 6 and a few other camera models also used between-the-lens leaf shutters in their lens systems. Thus, any time

5566-416: The Bronica ETRs, the ETRs'i (both producing a 6 × 4.5 cm. image), the SQ and the SQ-AI (producing a 6 × 6 cm image like the Hasselblad), and the Zenza-Bronica G system (6 × 7 cm). Certain Mamiya medium-format SLRs, discontinued camera systems such as the Kowa 6 and a few other camera models also used between-the-lens leaf shutters in their lens systems. Thus, any time

5687-625: The Canon Pellix and Sony SLT cameras , along with several special-purpose high-speed cameras (such as the Canon EOS-1N RS), whose mirror was a fixed beamsplitting pellicle . Focus can be adjusted manually by the photographer or automatically by an autofocus system. The viewfinder can include a matte focusing screen located just above the mirror system to diffuse the light. This permits accurate viewing, composing and focusing, especially useful with interchangeable lenses. Up until

5808-499: The Canon Pellix and Sony SLT cameras , along with several special-purpose high-speed cameras (such as the Canon EOS-1N RS), whose mirror was a fixed beamsplitting pellicle . Focus can be adjusted manually by the photographer or automatically by an autofocus system. The viewfinder can include a matte focusing screen located just above the mirror system to diffuse the light. This permits accurate viewing, composing and focusing, especially useful with interchangeable lenses. Up until

5929-457: The SLR's versatility, most manufacturers have a vast range of lenses and accessories available for them. Compared to most fixed-lens compact cameras, the most commonly used and inexpensive SLR lenses offer a wider aperture range and larger maximum aperture (typically f /1.4 to f /1.8 for a 50 mm lens). This allows photographs to be taken in lower light conditions without flash, and allows

6050-408: The SLR's versatility, most manufacturers have a vast range of lenses and accessories available for them. Compared to most fixed-lens compact cameras, the most commonly used and inexpensive SLR lenses offer a wider aperture range and larger maximum aperture (typically f /1.4 to f /1.8 for a 50 mm lens). This allows photographs to be taken in lower light conditions without flash, and allows

6171-642: The SLR. In 1952, Asahi developed the Asahiflex and in 1954, the Asahiflex IIB . In 1957, the Asahi Pentax combined the fixed pentaprism and the right-hand thumb wind lever. Nikon , Canon and Yashica introduced their first SLRs in 1959 (the F , Canonflex , and Pentamatic, respectively). Canon, Nikon and Pentax have all developed digital SLR cameras (DSLRs) using the same lens mounts as on their respective film SLR cameras. Konica Minolta did

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6292-464: The SLR. In 1952, Asahi developed the Asahiflex and in 1954, the Asahiflex IIB . In 1957, the Asahi Pentax combined the fixed pentaprism and the right-hand thumb wind lever. Nikon , Canon and Yashica introduced their first SLRs in 1959 (the F , Canonflex , and Pentamatic, respectively). Canon, Nikon and Pentax have all developed digital SLR cameras (DSLRs) using the same lens mounts as on their respective film SLR cameras. Konica Minolta did

6413-448: The ability to adjust to changes in lighting during the actual exposure which was useful for specialist applications such as photomicrography and astronomical photography. Leica later used a variation of this system, as did Pentax with their Integrated Direct Metering ( IDM ) in the LX camera. A variation of this "OTF" system was used on early Olympus E-Series digital cameras to fine-tune

6534-428: The ability to update the lens technologies due to the reduced distance between the back of the lens and the sensor resulting from the removal of the mirror. Film-based SLRs are still used by a niche market of enthusiasts and format lovers. SLR camera A single-lens reflex camera ( SLR ) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits

6655-420: The actual exposure. Consequently, these light sensors could traditionally be used for ambient light TTL metering only. In newer SLRs as well as in almost all DSLRs, they can also be utilized for preflash TTL metering, where the metering is carried out before the mirror flips up using a small preflash of known intensity and the necessary amount of flash light is extrapolated from the reflected flash light measured by

6776-406: The advantages of metering with real-time feedback and without preflash. TTL metering systems have been incorporated into other types of cameras as well. Most digital " point-and-shoot cameras " use TTL metering, performed by the imaging sensor itself. In many advanced modern cameras multiple 'segments' are used to acquire the amount of light in different places of the picture. Depending on the mode

6897-443: The amount of light travelling to the film plane or sensor and also can distort the light passing through them, resulting in a less-sharp image. To avoid the noise and vibration, many professional cameras offer a mirror lock-up feature, however, this feature totally disables the SLR's automatic focusing ability. Electronic viewfinders have the potential to give the 'viewing-experience' of a DSLR (through-the-lens viewing) without many of

7018-443: The amount of light travelling to the film plane or sensor and also can distort the light passing through them, resulting in a less-sharp image. To avoid the noise and vibration, many professional cameras offer a mirror lock-up feature, however, this feature totally disables the SLR's automatic focusing ability. Electronic viewfinders have the potential to give the 'viewing-experience' of a DSLR (through-the-lens viewing) without many of

7139-436: The autofocus system or for wireless communication with off-camera flash units. A pre-flash is often used to determine the amount of light that is reflected from the subject, which sets the duration of the main flash at time of exposure. Some cameras also employ automatic fill-flash, where the flash light and the available light are balanced. While these capabilities are not unique to the SLR, manufacturers included them early on in

7260-436: The autofocus system or for wireless communication with off-camera flash units. A pre-flash is often used to determine the amount of light that is reflected from the subject, which sets the duration of the main flash at time of exposure. Some cameras also employ automatic fill-flash, where the flash light and the available light are balanced. While these capabilities are not unique to the SLR, manufacturers included them early on in

7381-551: The cameras using this configuration (e.g. the Minolta 9000) are virtually immune against measurement errors caused by light reaching the metering cells at larger angles, for example with tilt–shift lenses . Metering cells located at the bottom of the mirror box using light reflected off the film are also used in all film SLRs supporting the classical form of real-time TTL flash metering. Some early Pentax DSLRs could use this same configuration for TTL flash metering as well, but since

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7502-567: The capability to control perspective. With a triple-extension bellows 4" × 5" camera such as the Linhof SuperTechnika V, the photographer can correct certain distortions such as "keystoning", where the image 'lines' converge (i.e., photographing a building by pointing a typical camera upward to include the top of the building). Perspective correction lenses are available in the 35 mm and medium formats to correct this distortion with film cameras, and it can also be corrected after

7623-495: The capability to control perspective. With a triple-extension bellows 4" × 5" camera such as the Linhof SuperTechnika V, the photographer can correct certain distortions such as "keystoning", where the image 'lines' converge (i.e., photographing a building by pointing a typical camera upward to include the top of the building). Perspective correction lenses are available in the 35 mm and medium formats to correct this distortion with film cameras, and it can also be corrected after

7744-462: The disadvantages. More recently, Sony have resurrected the pellicle mirror concept in their " single-lens translucent " (SLT) range of cameras. SLRs vary widely in their construction and typically have bodies made of plastic or magnesium. Most manufacturers do not cite durability specifications, but some report shutter life expectancies for professional models. For instance, the Canon EOS 1Ds MkII

7865-405: The disadvantages. More recently, Sony have resurrected the pellicle mirror concept in their " single-lens translucent " (SLT) range of cameras. SLRs vary widely in their construction and typically have bodies made of plastic or magnesium. Most manufacturers do not cite durability specifications, but some report shutter life expectancies for professional models. For instance, the Canon EOS 1Ds MkII

7986-506: The exposure just before the first curtain was released; for this to work, the first curtain was coated in a neutral grey colour. The process of calculating the correct amount of flash light can also be done 'through the lens'. This is being done in a significantly different way than non-flash 'through the lens' metering. The actual metering itself happens in two different ways, depending on the medium. Digital TTL works differently than analog TTL. The analog version of TTL works as follows: when

8107-529: The exposure. In addition, the movement of the reflex mirror takes time, limiting the maximum shooting speed. The mirror system can also cause noise and vibration. Partially reflective (pellicle) fixed mirrors avoid these problems and have been used in a very few designs including the Canon Pellix and the Canon EOS-1N RS , but these designs introduce their own problems. These pellicle mirrors reduce

8228-405: The exposure. In addition, the movement of the reflex mirror takes time, limiting the maximum shooting speed. The mirror system can also cause noise and vibration. Partially reflective (pellicle) fixed mirrors avoid these problems and have been used in a very few designs including the Canon Pellix and the Canon EOS-1N RS , but these designs introduce their own problems. These pellicle mirrors reduce

8349-403: The exposure. There are various designs for focal plane shutters. Early focal-plane shutters designed from the 1930s onwards usually consisted of two curtains that travelled horizontally across the film gate: an opening shutter curtain followed by a closing shutter curtain. During fast shutter speeds, the focal-plane shutter would form a 'slit' whereby the second shutter curtain was closely following

8470-403: The exposure. There are various designs for focal plane shutters. Early focal-plane shutters designed from the 1930s onwards usually consisted of two curtains that travelled horizontally across the film gate: an opening shutter curtain followed by a closing shutter curtain. During fast shutter speeds, the focal-plane shutter would form a 'slit' whereby the second shutter curtain was closely following

8591-561: The fact with photo software when using digital cameras. The photographer can also extend the bellows to its full length, tilt the front standard and perform photomacrography (commonly known as ' macro photography '), producing a sharp image with depth-of-field without stopping down the lens diaphragm. Early SLRs were built for large format photography, but this film format has largely lost favor among professional photographers. SLR film-based cameras have been produced for most film formats as well as for digital formats. These film-based SLRs use

8712-561: The fact with photo software when using digital cameras. The photographer can also extend the bellows to its full length, tilt the front standard and perform photomacrography (commonly known as ' macro photography '), producing a sharp image with depth-of-field without stopping down the lens diaphragm. Early SLRs were built for large format photography, but this film format has largely lost favor among professional photographers. SLR film-based cameras have been produced for most film formats as well as for digital formats. These film-based SLRs use

8833-461: The film (OTF). In OTF metering used by Olympus, metering was performed in one of two ways — or a combination of both — depending upon the shutter speed in use. In the OM-2's Auto Dynamic Metering ( ADM ) system the first shutter curtain had the lens-facing side coated with a computer generated pattern of white blocks to emulate an average scene. As the mirror flipped-up the metering cell in the base of

8954-469: The first opening shutter curtain to produce a narrow, vertical opening, with the shutter slit moving horizontally. The slit would get narrower as shutter speeds were increased. Initially these shutters were made from a cloth material (which was in later years often rubberised), but some manufacturers used other materials instead. Nippon Kōgaku (now Nikon Corporation ), for example, used titanium foil shutters for several of their flagship SLR cameras, including

9075-469: The first opening shutter curtain to produce a narrow, vertical opening, with the shutter slit moving horizontally. The slit would get narrower as shutter speeds were increased. Initially these shutters were made from a cloth material (which was in later years often rubberised), but some manufacturers used other materials instead. Nippon Kōgaku (now Nikon Corporation ), for example, used titanium foil shutters for several of their flagship SLR cameras, including

9196-425: The flash fires immediately after the shutter opens), the preflashes and main flash appear as one to the human eye, since there is very little time between them. When using rear-curtain flash (when the flash fires at the end of the exposure) and a slow shutter speed, the distinction between the main flash and the preflashes is more obvious. Some cameras and flash units take more information into account when calculating

9317-590: The focusing feature of a lens if they enter into the focusing helicoid. The problem of sensor cleaning has been somewhat reduced in DSLRs as some cameras have a built-in sensor cleaning unit. The price of SLRs in general also tends to be somewhat higher than that of other types of cameras, owing to their internal complexity. This is compounded by the expense of additional components, such as flashes or lenses. The initial investment in equipment can be prohibitive enough to keep some casual photographers away from SLRs, although

9438-539: The focusing feature of a lens if they enter into the focusing helicoid. The problem of sensor cleaning has been somewhat reduced in DSLRs as some cameras have a built-in sensor cleaning unit. The price of SLRs in general also tends to be somewhat higher than that of other types of cameras, owing to their internal complexity. This is compounded by the expense of additional components, such as flashes or lenses. The initial investment in equipment can be prohibitive enough to keep some casual photographers away from SLRs, although

9559-442: The incoming light hits the film, a part of it is reflected towards a sensor. This sensor controls the flash. If enough light is captured, the flash is stopped. During early testing of this system by Minolta and Olympus it was found that not all brands and types of film reflect the light to the same amount although the actual difference between brands was less than half a stop. The one exception was Polaroid's instant slide film which had

9680-453: The lens is measured and this value is used to calculate the amount of light necessary for the actual exposure. Multiple pre-flashes can be used to improve the flash output. Canon referred to this as Evaluative TTL (E-TTL) and later improved the system with E-TTL II . The first form of digital TTL by Nikon, called "D-TTL", was used in a few early models. Since then, the superior "i-TTL" system has been used. When using front-curtain flash (when

9801-442: The lens to the film, and another positioned above ( TLR or twin-lens reflex ) or to the side ( rangefinder ). Because the viewfinder and the film lens cannot share the same optical path, the viewing lens is aimed to intersect with the film lens at a fixed point somewhere in front of the camera. This is not problematic for pictures taken at a middle or longer distance, but parallax causes framing errors in close-up shots. Moreover, it

9922-442: The lens to the film, and another positioned above ( TLR or twin-lens reflex ) or to the side ( rangefinder ). Because the viewfinder and the film lens cannot share the same optical path, the viewing lens is aimed to intersect with the film lens at a fixed point somewhere in front of the camera. This is not problematic for pictures taken at a middle or longer distance, but parallax causes framing errors in close-up shots. Moreover, it

10043-468: The lens, is reflected upwards by the reflex mirror, into the pentaprism where it is reflected twice to correct the inversions caused by the lens, and align the image with the viewfinder . When the shutter is released, the mirror moves out of the light path, and the light shines directly onto the film (or in the case of a DSLR , the CCD or CMOS imaging sensor). Exceptions to the moving mirror system include

10164-420: The lens, is reflected upwards by the reflex mirror, into the pentaprism where it is reflected twice to correct the inversions caused by the lens, and align the image with the viewfinder . When the shutter is released, the mirror moves out of the light path, and the light shines directly onto the film (or in the case of a DSLR , the CCD or CMOS imaging sensor). Exceptions to the moving mirror system include

10285-405: The market for used SLRs has become larger particularly as photographers migrate to digital systems. The digital single-lens reflex camera has largely replaced the film SLR for its convenience, sales, and popularity at the start of the 21st century. These cameras were the marketing favorite among advanced amateur and professional photographers through the first two decades of

10406-405: The market for used SLRs has become larger particularly as photographers migrate to digital systems. The digital single-lens reflex camera has largely replaced the film SLR for its convenience, sales, and popularity at the start of the 21st century. These cameras were the marketing favorite among advanced amateur and professional photographers through the first two decades of

10527-508: The mass market, Leica's PLOOT reflex housing along with a 200 mm f4.5 lens paired to a 35 mm rangefinder camera body, debuted in 1935. The Soviet Спорт (“Sport”), also a 24 mm by 36 mm image size, was prototyped in 1934 and went to market in 1937. K. Nüchterlein's Kine Exakta (Germany, 1936) was the first integrated 35 mm SLR to enter the market. Additional Exakta models, all with waist-level finders, were produced up to and during World War II . Another ancestor of

10648-508: The mass market, Leica's PLOOT reflex housing along with a 200 mm f4.5 lens paired to a 35 mm rangefinder camera body, debuted in 1935. The Soviet Спорт (“Sport”), also a 24 mm by 36 mm image size, was prototyped in 1934 and went to market in 1937. K. Nüchterlein's Kine Exakta (Germany, 1936) was the first integrated 35 mm SLR to enter the market. Additional Exakta models, all with waist-level finders, were produced up to and during World War II . Another ancestor of

10769-662: The metering cells in the roof of the camera and is then applied during the exposure without any possible real-time feedback. There were a few particularly sophisticated film SLRs including the Olympus OM-2 , the Pentax LX , the Nikon F3 , and the Minolta 9000 , where metering cells located at the bottom of the mirror box were used for ambient light metering, depending on model either instead or in addition to metering cells in

10890-404: The mirror box and pentaprism/pentamirror. The mirror box also prevents lenses with deeply recessed rear elements from being mounted close to the film or sensor unless the camera has a mirror lockup feature; this means that simple designs for wide angle lenses cannot be used. Instead, larger and more complex retrofocus designs are required. The SLR mirror 'blacks-out' the viewfinder image during

11011-404: The mirror box and pentaprism/pentamirror. The mirror box also prevents lenses with deeply recessed rear elements from being mounted close to the film or sensor unless the camera has a mirror lockup feature; this means that simple designs for wide angle lenses cannot be used. Instead, larger and more complex retrofocus designs are required. The SLR mirror 'blacks-out' the viewfinder image during

11132-406: The mirror box measured the light reflected from the subject bouncing off this pattern of blocks. The timing of the release of the second curtain was adjusted in real time during the actual exposure. As the shutter speed increased, the actual light reflecting off the film surface was measured and the timing of the second curtain's release adjusted accordingly. This gave cameras equipped with this system

11253-401: The mirror moves upwards from its resting position in the direction of the arrow, the focal plane shutter opens, and the image is projected onto the film or sensor in exactly the same manner as on the focusing screen. This feature distinguishes SLRs from other cameras as the photographer sees the image composed exactly as it will be captured on the film or sensor . Most 35 mm SLRs use

11374-401: The mirror moves upwards from its resting position in the direction of the arrow, the focal plane shutter opens, and the image is projected onto the film or sensor in exactly the same manner as on the focusing screen. This feature distinguishes SLRs from other cameras as the photographer sees the image composed exactly as it will be captured on the film or sensor . Most 35 mm SLRs use

11495-613: The modern SLR camera was the Swiss-made Alpa , which was innovative, and influenced the later Japanese cameras. The first eye-level SLR viewfinder was patented in Hungary on August 23, 1943, by Jenő Dulovits, who then designed the first 35 mm camera with one, the Duflex , which used a system of mirrors to provide a laterally correct, upright image in the eye-level viewfinder. The Duflex, which went into serial production in 1948,

11616-441: The modern SLR camera was the Swiss-made Alpa , which was innovative, and influenced the later Japanese cameras. The first eye-level SLR viewfinder was patented in Hungary on August 23, 1943, by Jenő Dulovits, who then designed the first 35 mm camera with one, the Duflex , which used a system of mirrors to provide a laterally correct, upright image in the eye-level viewfinder. The Duflex, which went into serial production in 1948,

11737-417: The necessary flash output, including the distance of the subject to the lens. This improves the lighting when a subject is placed in front of a background. If the lens is focused on the subject, the flash will be controlled to allow for proper exposure on the subject, thus leaving the background underexposed. Alternatively, if the lens is focused on the background, the background will be properly exposed, leaving

11858-523: The only choice for focal plane shutters at that time was 1 ⁄ 60 . Later, Nikon again pioneered the use of titanium for vertical shutters, using a special honeycomb pattern on the blades to reduce their weight and achieve world-record speeds in 1982 of 1 ⁄ 4000 second for non-sync shooting, and 1 ⁄ 250 with x-sync. Nowadays most such shutters are manufactured from cheaper aluminium (though some high-end cameras use materials such as carbon-fibre and Kevlar ). Another shutter system

11979-523: The only choice for focal plane shutters at that time was 1 ⁄ 60 . Later, Nikon again pioneered the use of titanium for vertical shutters, using a special honeycomb pattern on the blades to reduce their weight and achieve world-record speeds in 1982 of 1 ⁄ 4000 second for non-sync shooting, and 1 ⁄ 250 with x-sync. Nowadays most such shutters are manufactured from cheaper aluminium (though some high-end cameras use materials such as carbon-fibre and Kevlar ). Another shutter system

12100-500: The photographer has selected, this information is then used to correctly set the exposure. With a simple spot meter, a single spot on the picture is selected. The camera sets the exposure in order to get that particular spot properly exposed. On some modern SLR systems the spot metering area or zone can be coupled to the actual focusing area selected offering more flexibility and less need to use exposure lock systems. With multiple segment metering (also known as matrix or honeycomb metering),

12221-423: The photographer with considerably more control (i.e., how the image is viewed and framed) than would be the case with a view camera. In addition, some SLR lenses are manufactured with extremely long focal lengths, allowing a photographer to be a considerable distance away from the subject and yet still expose a sharp, focused image. This is particularly useful if the subject includes dangerous animals (e.g., wildlife);

12342-423: The photographer with considerably more control (i.e., how the image is viewed and framed) than would be the case with a view camera. In addition, some SLR lenses are manufactured with extremely long focal lengths, allowing a photographer to be a considerable distance away from the subject and yet still expose a sharp, focused image. This is particularly useful if the subject includes dangerous animals (e.g., wildlife);

12463-433: The read out of the image sensor itself for exposure metering in these modes. This also applies to Sony's SLT digital cameras, which use the image sensor for exposure metering all the time. As of 2012, no digital SLR or SLT camera on the market supported any form of real-time TTL flash metering using the image sensor. However, it can be expected that such methods will be introduced as image sensor technology progresses, given

12584-440: The reflectance properties of image sensors differ significantly from those of film, this method proved to be unreliable in practice. Therefore, digital SLR cameras typically don't support any real-time TTL flash metering and must use preflash metering instead. The ambient and flash light metering is then carried out by a metering module located in the roof of the camera (see above). Digital SLRs supporting live view or video will use

12705-417: The roof of the camera. Depending on model, the light was reflected down there either by a secondary mirror behind the half-transparent main mirror, a special reflective coating of the first shutter curtain, the surface of the film itself, or combinations thereof. One of the advantages of this approach is that the measuring result requires no adjustments when changing focusing screens or viewfinders. Also, some of

12826-531: The same, and after having bought Konica Minolta's camera division in 2006. Sony continues using the Minolta AF lens mount in their DSLRs, including cameras built around a semi-transparent fixed mirror . Samsung builds DSLRs based on the Pentax lens mount. Olympus , on the other hand, chose to create a new digital-only Four Thirds System SLR standard, adopted later by Panasonic and Leica. Contax came out with

12947-420: The same, and after having bought Konica Minolta's camera division in 2006. Sony continues using the Minolta AF lens mount in their DSLRs, including cameras built around a semi-transparent fixed mirror . Samsung builds DSLRs based on the Pentax lens mount. Olympus , on the other hand, chose to create a new digital-only Four Thirds System SLR standard, adopted later by Panasonic and Leica. Contax came out with

13068-405: The start of the 21st century. A cross-section ( or 'side-view') of the optical components of a typical SLR camera shows how the light passes through the lens assembly, is reflected by the mirror placed at a 45-degree angle, and is projected on the matte focusing screen . Via a condensing lens and internal reflections in the roof pentaprism the image appears in the eyepiece. When an image is taken,

13189-405: The start of the 21st century. A cross-section ( or 'side-view') of the optical components of a typical SLR camera shows how the light passes through the lens assembly, is reflected by the mirror placed at a 45-degree angle, and is projected on the matte focusing screen . Via a condensing lens and internal reflections in the roof pentaprism the image appears in the eyepiece. When an image is taken,

13310-605: The subject in the foreground typically overexposed. This technique requires both a camera capable of calculating the distance information, as well as the lens being capable of communicating the focal distance to the body. Nikon refers to this technique as "3D matrix metering", although different camera manufacturers use different terms for this technique. Canon incorporated this technique in E-TTL II. More advanced TTL flash techniques include off-camera flash lighting, where one or more flash units are located at different locations around

13431-552: The subject prefers anonymity to being photographed; or else, the photographer's presence is unwanted (e.g., celebrity photography or surveillance photography). Practically all SLR and DSLR camera bodies can also be attached to telescopes and microscopes via an adapter tube to further enhance their imaging capabilities. In most cases, single-lens reflex cameras cannot be made as small or as light as other camera designs—such as rangefinder cameras , autofocus compact cameras and digital cameras with electronic viewfinders (EVF)—owing to

13552-552: The subject prefers anonymity to being photographed; or else, the photographer's presence is unwanted (e.g., celebrity photography or surveillance photography). Practically all SLR and DSLR camera bodies can also be attached to telescopes and microscopes via an adapter tube to further enhance their imaging capabilities. In most cases, single-lens reflex cameras cannot be made as small or as light as other camera designs—such as rangefinder cameras , autofocus compact cameras and digital cameras with electronic viewfinders (EVF)—owing to

13673-420: The subject. In this case a 'commander' unit (which can be integrated in the camera body) is used to control all of the remote units. The commander unit usually controls the remote flashes by using flashes of visible or infrared light, although TTL-capable radio triggering systems are available. The photographer can normally vary the light ratios between the different flashes. The technique of using preflashes to get

13794-435: The top models, whereas the best rangefinder cameras adopted such features later. Many of the advantages of SLR cameras derive from viewing and focusing the image through the attached lens. Most other types of cameras do not have this function; subjects are seen through a viewfinder that is near the lens, making the photographer's view different from that of the lens. SLR cameras provide photographers with precision; they provide

13915-435: The top models, whereas the best rangefinder cameras adopted such features later. Many of the advantages of SLR cameras derive from viewing and focusing the image through the attached lens. Most other types of cameras do not have this function; subjects are seen through a viewfinder that is near the lens, making the photographer's view different from that of the lens. SLR cameras provide photographers with precision; they provide

14036-526: The values of the different segments are combined and weighted to set the correct exposure. Implementations of these metering modes vary between cameras and manufacturers, making it difficult to predict how a scene will be exposed when switching cameras. The first camera to feature through-the-lens light metering was by Japanese company Nikon , with a prototype rangefinder camera, the SPX. The camera used Nikon 'S' type rangefinder lenses. The Japanese company Pentax

14157-527: Was a focal-plane shutter SLR. Rollei later switched to a camera system of leaf-shutter design (e.g., the 6006 and 6008 reflexes) and their current medium-format SLRs are now all of the between-the-lens shutter design. Since the technology became widespread in the 1970s, SLRs have become the main photographic instrument used by dedicated amateur photographers and professionals. Some photographers of static subjects (such as architecture, landscape, and some commercial subjects), however, prefer view cameras because of

14278-527: Was a focal-plane shutter SLR. Rollei later switched to a camera system of leaf-shutter design (e.g., the 6006 and 6008 reflexes) and their current medium-format SLRs are now all of the between-the-lens shutter design. Since the technology became widespread in the 1970s, SLRs have become the main photographic instrument used by dedicated amateur photographers and professionals. Some photographers of static subjects (such as architecture, landscape, and some commercial subjects), however, prefer view cameras because of

14399-538: Was also the world's first SLR with an instant-return (a.k.a. autoreturn) mirror. The first commercially produced SLR that employed a roof pentaprism was the Italian Rectaflex A.1000, shown in full working condition on Milan fair April 1948 and produced from September the same year, thus being on the market one year before the east German Zeiss Ikon VEB Contax S , announced on May 20, 1949, produced from September. The Japanese adopted and further developed

14520-470: Was also the world's first SLR with an instant-return (a.k.a. autoreturn) mirror. The first commercially produced SLR that employed a roof pentaprism was the Italian Rectaflex A.1000, shown in full working condition on Milan fair April 1948 and produced from September the same year, thus being on the market one year before the east German Zeiss Ikon VEB Contax S , announced on May 20, 1949, produced from September. The Japanese adopted and further developed

14641-583: Was the first manufacturer to show an early prototype 35 mm behind-the-lens metering SLR camera , which was named the Pentax Spotmatic . The camera was shown at the 1960 photokina show. The first TTL light metering SLR was the 1963 Topcon RE Super , which had the CdS metering cell placed behind the reflex mirror. In the 1970s Olympus marketed the OM-2 camera, which measured the exposure directly off

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