Canon Patents

Patent: 50-300mm f/4.5-5.6 DO for EF-S & EF-M

That patent train continues for EF-M lens optical formulas, this time we see a 50-300mm f/4.5-5.6 DO lens for APS-C sized sensors. This optical formula patent shows the lens for both EF-M and EF-S mounts. It’s definitely interesting to see diffractive optics development for consumer grade cameras.

Patent Publication No. 2016-57444 (Google Translated)

  • Published 2016.4.21
  • Filing date 2014.9.9

Example 1

  • Zoom ratio 5.59
  • Focal length 51.77 135.00 289.53
  • F-number 4.65 5.05 5.85
  • Half angle of view (degrees) 14.78 5.78 2.70
  • Image height 13.66 13.66 13.66
  • The total lens length 126.05 169.37 184.15
  • BF 35.50 35.50 35.50

Example 2

  • Zoom ratio 5.90
  • Focal length 49.13 135.00 290.00
  • F-number 4.65 4.95 5.85
  • Half angle of view (degrees) 15.54 5.78 2.70
  • Image height 13.66 13.66 13.66
  • The total lens length 108.00 152.12 168.00
  • BF 15.69 15.69 15.69

We have yet to see any full frame optical formulas for a full frame mirrorless camera body. We don’t find this surprising as we expect any such camera be compatible with EF lenses.

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