Canon Patent: 135mm f/2, 400mm f/4 and 50mm f/2.5 defocus smoothing

New Canon Patent applications filed for a set of RF mount lenses with electronically controlled Defocus Smoothing (DS).

Defocus Smoothing is a technology Canon first introduced with the RF 85mm f/1.2L DS lens. The featured Canon patent might suggest more DS lenses are on their way.

Canon patent application 2020-199390 (Japan) discusses optical formulas and methods for three prime lenses with DS:

  • 135mm f/2
  • 400mm f/4
  • 50mm f/2.5

Example 1

  • Focal length: 133.05
  • F value: 2.06
  • Half angle of view: 9.24
  • Image height: 21.64
  • Overall length: 170.39
  • Back focus: 45.96

Example 2

  • Focal length: 399.84
  • F value: 4.00
  • Half angle of view: 3.10
  • Image height: 21.64
  • Overall length: 298.46
  • Back focus: 145.16

Example 3

  • Focal length: 49.00
  • F value: 2.50
  • Half angle of view: 23.82
  • Image height: 21.64
  • Overall length: 68.15
  • Back focus: 11.00

Here is a Video Review About What Defocus Smoothing is:

via asobinet

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