page_title: Pentax cameras
section_title: K Series
hierarchical_section_title: Pentax cameras / K Mount cameras / K Series
caption_attribution_description: English: A Pentax K1000 SE with a 50mm f/2 lens
context_page_description: and its predecessors, Pentax Corporation and Asahi Optical Co., Ltd.
  It covers from the first "Asahiflex" models in 1952 and their successor, the pivotal "Asahi Pentax" single-lens reflex camera, to the present time.
context_section_description: K2 (1975–1980)
  K2 DMD (1976–1980)
  KX (1975–1977)
  KM (1975–1977)
  K1000 (1976–1997)
  Three new models were introduced at once in 1975: the K2, KX and KM. What set these cameras apart from any earlier Pentax was the replacement of the M42 "universal" screw-lens mount with a proprietary bayonet mount system of its own, known as the K mount. Still the basis for Pentax lenses and cameras today, the K mount offered greater convenience and enabled the production of faster lenses such as the 50 mm f/1.2.  To keep M42 users in the Pentax system, an M42-K Mount adaptor was offered, enabling them to continue to use their existing lenses, albeit with the loss of automation and needing to accept "stop-down" metering, which causes the viewfinder's image to brighten or darken whenever the aperture's f/stop is changed.
  The K series cameras followed the design ethos of the previous Pentax Spotmatic series cameras, which were large and heavy, although rugged. But by 1975 there was already a general move to smaller 35mm cameras, led by the Olympus OM-1, so even as the K series was introduced Pentax were working on a new camera line, the M Series which started to appear in 1976.  All except the K1000 therefore had short production lives as the M Series took over the Pentax mid-range.
  The KM, the bottom of the original range, was almost identical to the Spotmatic F except for the K mount and the top plate cosmetics. It used a rather dated and slow CdS (cadmium sulfide) photocell for metering. The KX featured a better light meter using SPD (silicon photodiodes), visible aperture and shutter speeds in the viewfinder, and a mirror lock-up mechanism. The K2, the flagship model, incorporated aperture-priority autoexposure with a fully manually selectable range of shutter speeds from 8s to 1/1000. The only other aperture priority camera Pentax had made up to this point, the ES series, only had manual shutter speeds from 1/60 upwards. A special version of the K2, the K2 DMD, was introduced in 1976 that could use a data back and motor drive (hence "DMD"), together with other enhancements that aimed it at the professional market. Also in 1976 the K1000 was introduced, being the KM stripped of its self-timer, depth of field preview and some other facilities, and aimed at the lower end of the market in which it was very successful and continued in production until 1997, helped by the fact that for many years it was the usually recommended camera for students starting photographic or art courses.
caption: A Pentax K1000 SE with a SMC 50 mm f/2 lens
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