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photo:pentaxm42lenses

Pentax M42 lenses

introduction

  • ASAHI Optical produced M42 screw mount lenses for the 35mm film SLRs from 1957-1974
  • prior to 1957, the lens mount was a M37 screw, and after 1974, in response to the Olympus OM system, it was replaced by the Pentax K bayonet mount
  • in 1964, the Super designation means, the aperture mechanism did not need to be cocked manually by the photographer - like with the earlier “Auto-Takumar” lenses
  • in 1971, the Super-Multi-Coated lenses (“S-M-C”) added lens coating to reduce flare
  • later “SMC” lenses had rubber focus rings instead of metal

timeline

  • 1952-58:
    • M37 screw mount lenses (nearly all are silver) such as:
      • 50mm f/3.5
      • 58mm f/2.4
      • 83mm f/1.9
      • 100mm f/3.5
      • 135mm f/3.5
  • 1957-62:
    • M42 preset lenses such as:
      • 55mm f/1.8
      • 55mm f/2.2
      • 58mm f/2
      • 58mm f/2.4
      • 35mm f/4 - the 1st ever Japanese wide angle for SLR
      • 83mm f/1.9
      • 100mm f/3.5
      • 105mm f/2.8
      • 135mm f/3.5
      • 200mm f/3.5
      • 50mm f/4.0 macro 1:1
  • 1958-62:
    • M42 Auto-Takumar lenses with aperture diaphragms which required cocking such as:
      • 55mm f/1.8
      • 55mm f/1.9
      • 55mm f/2
      • 55mm f/2.2
      • 35mm f/2.3 - one of the world's 1st retrofocus lenses, and in 1958, it was the fastest aperture 35mm lens
      • 35mm f/3.5
      • 85mm f/1.8
      • 105mm f/2.8
      • 135mm f/3.5
  • 1962-71:
    • M42 single coated Super Takumars with semi-automatic aperture diaphragms no longer needing to be cocked:
      • 17mm f/4.0 fisheye
      • 28mm f/3.5
      • 35mm f/2.0
      • 35mm f/3.5
        • 240g, min. focus 0.45m, 8 or 7 elements in planar design but unlike most manufacturers, has used cemented spherical surfaces between the 4th and 5th element instead of flat which gives better off-axis aberration correction and thus better bokeh but slightly less sharp at infinity1), 6 blades, 49mm filter, special glass used in the later models - a highly regarded lens, one of the sharpest f/1.4 50mm lenses around in that era
        • early scarce model 230g and had 8 elements, this model had a cemented triplet with curved surfaces - very difficult and expensive to manufacture and which was sold at below cost, and thus a cheaper to make 7 element version was soon introduced.
          • can be identified by:
            • the location of the infrared focus mark which is to the right of the numeral 4 on the DOF scale.
            • the slightly protruding rear lens element NOT having a protective metal rim
            • the stop down switch, which is marked A M (rather than Auto Man as on the later versions).
            • the early version never has a dot on the aperture ring at the f/2 position whereas the later versions may or may not have a dot.
            • transitions from areas in focus to those out of focus are subtly smoother with the earlier lens.
            • less busy bokeh but more halos in specular highlights
            • more flare outdoors, less contrast
        • later more common model 240g had 7 elements, including one radioactive thorium element, and is marginally better optically
          • the radioactive element makes the glue between the REAR lens elements yellow over decades but this can be remedied by exposure to strong UV light such as sunlight for several weeks or UV lamp 24hrs/day for 7 days - see lenses with radioactive glass elements
        • nice bokeh with pleasantly soft images due to flare at wide apertures making for nice arty, painterly imagery
        • very sharp at f/5.6
        • extremely robust and well-made
        • cannot be used on a Canon 5D due to the protruding rear element hitting the mirror.
      • 50mm f/4.0 macro 1:2
      • 100mm f/4.0 bellows macro
      • 200mm f/5.6
      • 300mm f/6.3
      • 70-150mm f/4.5
  • 1971-76:
    • M42 multi-coated Super Takumars (SMC), most are coupled allowing open aperture metering for use with the Pentax Spotmatic SLRs
      • 17mm f/4.0 fisheye
      • 20mm f/4.5
      • 24mm f/3.5
      • 28mm f/3.5
      • 35mm f/2.0
      • 35mm f/3.5
      • 50mm f/1.4 - 8 blades instead of 6 in the last
      • 55mm f/1.8
      • 50mm f/4.0 macro
      • 100mm f/4.0 macro
      • 100mm f/4.0 bellows macro
      • 85mm f/1.8
      • 105mm f/2.8
      • 120mm f/2.8
      • 135mm f/3.5
      • 135mm f/2.5
      • 150mm f/4.0
      • 200mm f/4.0
      • 300mm f/4.0
      • 400mm f/5.6
      • 85-210mm f/4.5

the 85mm lenses

  • 83mm f/1.9 Takumar (M37) 1953-57
  • 83mm f/1.9 Takumar (M42) 1957-59
  • 85mm f/1.8 Auto-Takumar 1960-64
  • 85mm f/1.9 Super Takumar 1964-1971
  • 85mm f/1.9 Super Multi Coated Takumar 1971-72
  • 85mm f/1.8 Super Multi Coated Takumar 1972-74
photo/pentaxm42lenses.txt · Last modified: 2011/09/23 13:29 by gary