Pentax 645 mount was developed by Pentax in the early 1980s, and released in 1984 with Pentax 645 camera. It is a bayonet mount with three tabs made for medium format film, with a focal flange distance of 70.87mm and a throat diameter of 61.2mm. Mount supports electric and digital communication, film and digital sensors with an aspect ratio of 4:3, for a 6\u00d74.5cm film format. The aperture is controlled mechanically, with a lens clutch. Focus can be achieved manually, as well as automatically – mount supports screw-drive and digital focus control with lenses with built-in focus motors. There is support for in-lens stabilization.<\/p>\n\n\n\n
There are three film bodies and two digital bodies. Film bodies include the original, manual focus 645, and later models — 645N and 645N II, with autofocus support when used with FA 645-series lenses. Digital bodies are the original 645D with a 40mpx Kodak CCD sensor, and the later 645Z with a 51mpx Sony CMOS sensor, both 44\u00d733mm in size.<\/p>\n\n\n\n
Compared to the usual 35mm format, the approximate crop factor of Pentax 645 mount lenses is 0.62\u00d7 for film-era full-frame lenses and 0.79\u00d7 for digital bodies with 44\u00d733mm sensors.<\/p>\n\n\n\n
Jump to: A645<\/a><\/strong>, Leaf shutter lenses<\/a><\/strong>, FA645<\/a><\/strong>, DFA645 and DA645 lenses<\/a><\/strong>, 3rd<\/sup> party lenses<\/strong><\/a>.<\/p>\n\n\n\n A 645 series lenses are manual focus, auto-aperture lenses, the functional equivalent of Pentax K-mount A series lenses.<\/p>\n\n\n\n Lenses labelled as LS have leaf shutters built-in, using flash with those lenses is possible for all speeds of their shutters, up to 1\/500s. LS lenses are missing an A setting on the aperture ring, preventing the camera from using Program and Shutter priority modes.<\/p>\n\n\n\n FA 645 series lenses support screw-drive driven autofocus and are the functional equivalent of Pentax K-mount FA series lenses.<\/p>\n\n\n\n The latest series of lenses is optimised from the ground up for digital sensors. While most of the lenses fully cover a 6\u00d74.5cm film frame, leading to the D FA 645 designation, two of the lenses carry the DA 645 designation, indicating that their image circle covers only the smaller size of the sensor, making them unsuitable for film cameras.<\/p>\n\n\n\n These lenses aren’t always exclusively made in the Pentax 645 mount, but they have a native Pentax 645 mount and are usually available brand new. Ivanichek Petzvar is a fully manual lens, with no aperture information transferred to the camera.<\/p>\n\n\n\nPentax-A 645 lenses<\/h2>\n\n\n\n
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Leaf shutter lenses<\/h2>\n\n\n\n
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Pentax-FA 645 lenses<\/h2>\n\n\n\n
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Pentax-D FA 645 and DA 645 lenses<\/h2>\n\n\n\n
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Notable 3rd<\/sup> party Pentax 645 lenses<\/h2>\n\n\n\n
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References<\/h2>\n\n\n\n