see also:

• super telephoto mirror lenses

• NB. these lenses are often branded Rokinon, Opteka, Pro Optic, Vivitar, Bower, Walimex, Albinar, Falcon
• this super telephoto lens introduced in 2010?? is a catadioptric mirror lens, and as with all such mirror lenses, share the following characteristics:
  • manual focus
  • fixed aperture (in this case f/6.3)
  • 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

• 300mm focal length and field of view (5.4° ??) at infinity focus
• fixed f/6.3 aperture
• 9 lens elements, 9 groups, 1 ED (multicoated)
• closest focus 0.09m
• 95mm filter thread but mount turns when you focus + 25.5mm rear filter
• 74mm diameter, 65mm long and 320g
• cropped sensor camera mounts only (not full frame)
• ~$280
• Samyang website

• thephoblographer review