History of the single-lens reflex camera
From Wikipedia, the free encyclopedia
The history of the single-lens reflex camera began in the early 20th century, but it was not until the 1960s that the format became popular. It remains the camera design of choice for most professional and ambitious amateur photographers.
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[edit] Early large and medium format SLRs
The single-lens reflex concept was developed in the early 1900s with large format equipment. Graflex of the United States produced SLR cameras as early as 1909. While SLR cameras were not very popular at the time, they proved useful for some work. These cameras were used at waist level; the ground glass screen was viewed directly, using a large hood to keep out the light. In most cases, the mirror had to be raised as a separate operation before the shutter could be operated.
Following camera technology in general, SLR cameras became available in smaller and smaller sizes; medium format SLRs soon became common; at first larger box cameras, and later "pocketable" models such as the Ihagee Vest-Pocket Exakta of 1933.
[edit] Development of the 35 mm SLR
The first 35mm SLR was the German Ihagee Kine-Exakta in 1936, which was fundamentally a scaled-down Vest-Pocket Exakta. This camera used a waist-level finder. Further Exakta models were produced before and during the Second World War, making the Exakta the first 35mm SLR system. The Ihagee factory in Dresden was destroyed by bombing in 1945.
Meanwhile, Zeiss began work on a 35mm SLR in 1936 or 1937. This used an eye-level pentaprism which allowed viewing of an image oriented correctly left to right and while the camera was held up to the face. Waist-level finders show a reversed image while the operator of the camera has their head bowed downwards. To brighten the image, Zeiss incorporated a fresnel lens in between the ground-glass screen and pentaprism, forming the conventional SLR design still used today. However, the war intervened, and the Zeiss SLR did not emerge as a production camera until Zeiss in newly-created East Germany introduced the Contax S in 1949. This was the first "fixed" eye-level pentaprism SLR.
[edit] Rise of the Japanese SLRs
The earliest Japanese SLR was perhaps the Shinkoflex, a 6x6 camera made by Yamashita Shōkai from 1940. But before and after World War II, Japanese camera makers concentrated on rangefinder and twin-lens reflex cameras (as well of course as simpler, viewfinder cameras), similar to those of the Western makers. Asahi took a different path, inspired by the German SLRs. Its first model, the Asahiflex I, existed in prototype form in 1951 and production in 1952, making it the first Japanese-built 35mm SLR. The Asahiflex IIB of 1954 was the first SLR with an instant-return mirror. Previously, the mirror would remain up and the viewfinder black until the shutter was cocked for the next shot.
Orion's (soon to be Miranda's) Miranda SLR, sold in Japan from August 1955, was narrowly the first Japanese pentaprism SLR; it featured a removable pentaprism for eye or waist level use. In 1957, the Asahi Pentax became the first Japanese fixed-pentaprism SLR; its success led Asahi to eventually rename itself Pentax. This was the first SLR to use the right-hand rapid thumb wind lever of the Leica M3 of 1954 and Nikon S2 of 1955. This control layout was used on the vast majority of SLRs in the next 30 years, although the Nikkormat and Olympus OM series would instead have the shutter speed control around the lens mount. Asahi and many other camera makers used the M42 lens mount from the Contax S, often anachronistically known as the Pentax screw mount.
The Zunow SLR, which went on sale in 1958 (in Japan only), was the first with automatic stop-down to a preset aperture: set an f1.8 lens at f5.6, for example and you would still view through it at f1.8 until you pressed the shutter button. 1959 saw the first SLRs from Canon (the Canonflex) and Nikon (the F). The Canon was a moderate success. Nikon's enormously successful F, though, was the camera that demonstrated the superiority of the SLR and of the Japanese camera manufacturers, and was the first SLR system taken seriously by the general population of professional photographers. After the Nikon F, the more expensive rangefinder cameras (those with focal plane shutters) became niche products.
While little on the F was truly new, it was a well-made camera, and adhered closely to the control scheme of the Nikon rangefinder cameras, Asahi Pentax, etc. Instead of the M42 screw mount, Nikon introduced the F-mount bayonet lens mount system, still in use in a much modified form today. The F was a modular camera, in which various parts (pentaprism, focusing screen, film back, etc.) could be changed in order make it better fit the task. It was the first 35 mm camera offered with a successful motor drive system. Unlike much of the competition, it was released with a full range of lenses from 21 mm to 1000 mm focal length. Subsequent top-of-the-line Nikon models carried on the F series, which has as of 2005 reached the F6 (although this has a fixed finder).
Minolta's first SLR, the SR-2, was introduced to the export market in the same year (in fact, at the same Philadelphia show as the Canon and Nikon products) but had been on sale in Japan since August 1958.
It was the Japanese who introduced TTL Metering in production cameras. Pentax showed a prototype Pentax Spotmatic with TTL spot metering in 1961, but Tokyo Optical's RE Super preceded it into production in 1962 — production Spotmatics didn't appear until 1964, with a center-weighted meter. Most other camera systems followed suit and incorporated TTL metering; Topcon and Miranda cameras used light meters behind a partially silvered area of the mirror, while most other systems used a TTL meter built into the pentaprism itself. The Nikon F was updated with pentaprism TTL metering with the Photomic series of prisms.
Other notable Japanese SLRs from the early period include the Minolta SRT 101, a very robust camera body.
[edit] The 1970s: Towards perfection
The SLR camera systems without Autofocus had the peak of their development in the 1970s. A breakthrough were the Minolta XD-7 and XD-11 camera bodies. Information like aperture and exposure time was visible through the excellent viewfinder. Both automatic exposure modes were possible: shutter priority mode and aperture priority mode. This was the first SLR camera with both of these features. At that time several cameras from Minolta and Leica were related.
The most significant turning point of the Seventies for the 35mm SLR camera industry was the emergence of Olympus. After runaway successes with the Pen-series - and in particular the SLR-based Pen-F, Pen-Ft and Pen-FV half-frame cameras - its chief designer Yoshihisa Maitani revolutionised the entire SLR design by introducing the M-1, later renamed to OM-1, to avoid trademark problems with Leica. The mechanical manual OM-1 was significantly smaller and lighter but no less functional and in fact was supported by one of the most comprehensive 35mm SLR lens and accessory system available. Maitani parred weight by totally redesigning the SLR from the ground up with unprecedented use of metallurgy including the repositioning of the slow and high-speed shutter mechanicals below the mirror box to lower the camera profile.
Olympus repeated the feat some years on with the OM-2, featuring aperture-priority automatic with the world's first TTL flash metering and Off-The-Film (OTF) available light metering systems, banishing the tediousness of calculating apertures for flash-to-distance settings. At the same time, the OM System was further enlarged and with it, its Zuiko lenses gained ground and reputation as amongst the sharpest lenses in the world. In the eighties, Olympus upped the ante further by replacing the OM-1 and OM-2 with the OM-3 mechanical manual and OM-4 automatic; both with unmatched multi-spot metering capabilities. Both soon evolved into the last of the OM SLRs, the titanium-bodied OM-3Ti and OM-4Ti, introducing at the same time, the world's fastest flash sync speeds, at 1/2000 second with their new Full-Synchro strobe-based flash technology.
[edit] The autofocus revolution
Autofocus compact cameras had been introduced in the late 1970s. The SLR market of the time was crowded, and autofocus seemed an excellent option to attract novice photographers. The first SLR to demonstrate autofocus capability was the Pentax ME-F of 1981, which used one special autofocus lens with an integral motor, while in the same year Canon introduced a self-contained autofocus lens, the 35-70 mm AF, which contained an optical triangulation system that would focus the lens on the subject in the exact center when a button on the side of the lens was pushed. It would work on any Canon FD camera body.
These, and other experiments in autofocus from other manufacturers, had limited success. The first true AF camera that did succeed was the Minolta Maxxum 7000 of 1985. Minolta introduced a completely new lens system, incompatible with its previous system, in which the lenses' focusing action was driven from a motor in the camera body. This reduced complexity in the camera body and the lens. Canon responded with the T80 and a range of three motor-equipped AC lenses, but this was regarded as a stopgap move.
In 1987, Canon followed Minolta in introducing a new, incompatible system: EOS, the Electro-Optical System. Unlike Minolta's motor-in-body approach, this kept the motor within the lens; new, compact motor designs meant that both focus and aperture could be driven electrically without motor bulges in the lens. The Canon EF lens mount features no mechanical linkages; all communication between body and lens is electrical.
Nikon and Pentax both chose to extend their existing lens mounts with autofocus capability, retaining the ability to use older manual-focus lenses with an autofocus body.
These four companies "The Big Four" were among the few to transition successfully to autofocus. Other camera manufacturers did introduce functionally successful AF SLR's but they still lost sales, and in almost all cases eventually withdrew from the SLR market. Leica still manufactures its R series of manual-focus SLRs, while Nikon still produces a manual-focus SLR as (until recently) did Minolta. Olympus produced its OM system until 2002, and thereafter introduced the world's first purely digital SLR format called(the Four Thirds System)and was joined by Panasonic, Leica, Sigma, Sanyo, Fuji and Kodak. Sigma, Fuji, and Kyocera/Contax have also managed to survive.
[edit] Medium format SLRs
While twin-lens reflex cameras have been more numerous in medium format, many medium format SLRs have been and are produced. Hasselblad of Sweden has one of the best known ranges. Pentax produces two medium-format SLR systems, the Pentax 645 and Pentax 67 series. Rollei, Fuji, Mamiya, Bronica and Kyocera have also had a SLR systems in recent years; Mamiya produces what is termed a medium format digital SLR.
The Polaroid SX-70 was one of the few SLRs produced by that company, and a rare case of a folding SLR.
