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photo:tamron500mmf8

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Tamron SP 500mm f/8.0 BBAR mirror lens

introduction

  • this super telephoto lens introduced in 1983 (discontinued in 2005) is a catadioptric mirror lens, and as with all such mirror lenses, share the following characteristics:
    • manual focus
    • fixed aperture (in this case f/8.0)
    • virtual elimination of chromatic aberration as uses mirror rather than lenses
      • also means focus position for infrared photography is the same as for light photography
    • central mirror:
      • allows much more compact lens length as the optic path is reflected internally twice
      • by necessity, blocks some of the light and thus causes:
        • decrease in image contrast
        • characteristic “doughnut” shaped bokeh imagery in out of focus areas

specs

  • 500mm focal length and field of view (5°) at infinity focus
  • fixed f/8.0 aperture
  • 7 elements in 4 groups (BBAR multicoated)
  • closest focus 1.7m which gives 1:3 macro
  • 82mm filter thread non-rotating
  • 30.5mm rear filter
  • 84mm diameter, 92mm long and 595g
  • Adaptall II camera mount
  • NB. there was an earlier model called 55B which did have some optical problems due to mirror design. All that was optimized in the 55BB model

reviews

photo/tamron500mmf8.txt · Last modified: 2014/05/18 10:07 by gary1