Canon Patent: RF-S 15-45mm F3.5-6.3 Lens For APS-C Imaging Sensors

Canon Patent

And here is another Canon patent application for the RF-S mount. Canon patent 2023182958 (Japan, published 2023-12-27) discusses optical formulas for a lens for the RF-S mount, 15-45mm F3.5-6.3.

From the patent literature:

  • An object of the present invention is to provide a zoom lens with good optical performance over the entire zoom range.
  • [Background Art] Conventionally, a lens has a first lens group with a negative refractive power and a second lens group with a positive refractive power, which are arranged in order from the object side to the image side, and includes a focal length in the standard range. Zoom lenses are known (see Patent Documents 1 and 2).
  • However, in the zoom lens disclosed in Patent Document 1, the entire lens system is large and it is not possible to achieve sufficiently high image quality.¬†Furthermore, in the zoom lens disclosed in Patent Document 2, various aberrations such as spherical aberration and coma aberration are not sufficiently corrected.
  • An object of the present invention is to provide a zoom lens with good optical performance over the entire zoom range.

Example 1

  • Focal length: 15.36-43.10
  • F value: 3.60-6.44
  • Half angle of view: 35.76-17.59
  • Total length: 76.36-73.51
  • Back focus: 10.45

Example 2

  • Focal length: 18.45-43.10
  • F value: 4.10-6.44
  • Half angle of view: 31.58-17.59
  • Total length: 80.15-79.38
  • Back focus: 13.47-33.69

Example 3

  • Focal length: 16.23-43.10
  • F value: 3.61-6.44
  • Half angle of view: 32.27-17.59
  • Total length: 88.10-88.68
  • Back focus: 10.87

[via asobinet]

Canon Patent: 20-120mm F4 And 18-100mm F4 For RF-S Mount

Canon Patent

A new Canon patent application (well, not really new) for two lenses for the RF-S mount.

Canon patent application 2023182926 (Japan, published 2023-12-27) discusses optical formulas for two RF-S mount lenses:

  • 20-120mm F4
  • 18-100mm F4

From the patent literature:

  • An object of the present invention is to provide a fixed-length zoom lens having a high zoom magnification and high optical performance over the entire zoom range.
  • BACKGROUND ART
    Fixed-length zoom lenses are known in which the overall length of the lens does not change during zooming. Such a zoom lens is suitable for video shooting and the like because the center of gravity does not change much during zooming. In recent years, zoom lenses have been required to have high zoom magnification and high optical performance over the entire zoom range for video applications.
  • However, although the zoom lens described in Patent Document 1 is superior in that there are fewer lens groups that move during zooming and focusing, improvements in optical performance are required as the resolution of sensors has increased in recent years
  • On the other hand, in the zoom lens described in Patent Document 2, high optical performance is obtained over the entire zoom range by increasing the number of lenses in each lens group, but an even higher zoom magnification is required.
  • The present invention provides a full-length fixed zoom lens having a high zoom magnification and high optical performance over the entire zoom range.

Example 1

  • Focal length: 20.02-119.95
  • F value: 4.08
  • Half angle of view: 34.40-6.31
  • Image height: 12.33-13.66
  • Total length: 165.00
  • Back focus: 13.54

Example 2

  • Focal length: 20.01-134.95
  • F value: 4.08
  • Half angle of view: 34.29-5.61
  • Image height: 12.33-13.66
  • Total length: 168.51-168.50
  • Back focus: 13.82

Example 3

  • Focal length: 18.41-101.96
  • F value: 4.08
  • Half angle of view: 36.59-7.42
  • Image height: 12.33-13.66
  • Total length: 146.50146.49
  • Back focus: 13.77

[via asobinet]