Canon patent for EF 600mm f/4 DO IS USM lens

Canon filed a patent for an EF 600mm f/4 DO IS lens, i.e. a lens with diffractive optical elements.

• Patent Publication No. 2015-11171
  • Published 2015.1.19
  • Filing date 2013.6.28
• Example 2
  • Focal length 588.30mm
  • Fno. 4.12
  • Angle of view 2.11 °
  • Image height 21.64mm
  • The total lens length 397.80mm
  • BF 2.02mm
  • Positive ShiboTadashi
  • Inner focus
  • Vibration control

[via Egami]