Canon patent for 20-45mm f/2.8-4 lens

Canon filed a patent for a 20-45mm f/2.8-4 lens. Somewhat unusual specs, but who knows.

• Patent Publication No. 2015-197593
  • Published 2015.11.9
  • Filing date 2014.4.1
• Example
  • Zoom ratio 2.25
  • Focal length f = 20.00 23.60 45.00
  • Fno. 2.75 2.90 4.16
  • Half angle of 47.25 42.51 25.68
  • Image height 21.64 21.64 21.64
  • Overall length 158.28 156.32 173.36
  • BF 42.05 46.10 73.14

[via Egami]