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photo:minoltaafreflex500mm

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Sony / Minolta AF Reflex 500mm f/8.0 mirror lens

introduction

  • this super telephoto lens is a catadioptric mirror lens, and as with all such mirror lenses, share the following characteristics:
    • 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
  • originally designed by Minolta in 1991 and re-introduced by Sony in 2006

specs

  • 500mm focal length and field of view (5°) at infinity focus (but gradually changes to 320mm when closer focus at 4m - this may be an issue with cameras where you need to set a focal length for the image stabiliser to work optimally)
  • fixed f/8.0 aperture
  • 5 groups / 7 elements
  • closest focus 4m which gives 19cm x 28cm (7.5“ x 11.0”) field of image
  • 82mm front filter thread
  • rear section filter holder, drop-in type (with 42mm filter)
  • built-in sun-shade / lens hood
  • 89mm diameter, 118mm long and 665g (compare this with 255mm and 1.3kg for a 400mm refractor style lens)
  • heavier and bigger than the Olympus OM 500mm f/8.0 mirror lens

reviews

photo/minoltaafreflex500mm.txt · Last modified: 2014/05/15 03:58 by gary1