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Canon Patent: Canon RF 28-70mm f/2.8 IS STM (the released lens?)

Canon Patent

Here is a new Canon patent, and it appear it is referring to the recently released RF 28-70mm f/2.8 IS STM lens.

Canon patent 2024140521 (Japan, published 10/10/2024) discusses optical formulas for a 28-70mm f/2.8 IS STM lens for the RF mount.

From the patent literature:

  • The present invention provides a zoom lens that has high optical performance, a high zoom ratio, and is compact.
  • Description of the Related Art
    In recent years, imaging optical systems used in imaging devices have been required to have high optical performance, a high zoom ratio, and a small size.
  • The zoom lens of Patent Document 1 has a lens group arranged in the order of positive, negative, positive, positive, negative, positive, from the object side to the image side. However, since the refractive power of the second lens group is strong, the chromatic aberration of magnification at the wide-angle end tends to become large, and the fluctuation of the curvature of field occurring during zooming tends to become large .
  • SUMMARY OF THE PRESENT EMBODIMENTS: An object of the present invention is to provide a zoom lens which has high optical performance, a high zoom ratio and is compact.

Example 1

  • Focal length: 28.80-67.90
  • F-number: 2.88-2.92
  • Half angle of view: 34.93-17.67
  • Image height: 21.64
  • Total length: 132.38-158.83
  • Back Focus: 15.39-34.87

More Canon patents are listed here.

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