A new Canon patent for two lenses for mirrorless cameras, one for APS-C and the other for full-frame. Both have inner zoom mechanism.

Canon patent application 2024076793 (Japan, published 6/6/2024) discusses optical formulas for two lenses with inner zoom:

• 12-30mm f4-6.3 IS (APS-C)
• 20-40mm f/4 IS (full-frame)

From the patent literature:

• An object of the present invention is to provide a negative lead type wide-angle zoom lens that is small and lightweight and has high optical performance over the entire zoom range.
• BACKGROUND ART In recent years, it has been desired that an imaging optical system used in an imaging device be a small zoom lens that has a wide angle of view and has high optical performance over the entire zoom range.
• Patent Document 1 discloses a negative lead type wide-angle zoom lens in which a first lens group with a negative refractive power is disposed closest to the object side as a zoom lens whose entire system is small and whose angle of view can be easily widened. Proposed.
• The negative lead type wide-angle zoom lens proposed in Patent Document 1 widens the angle of view by moving the first lens group with negative refractive power when zooming from the wide-angle end to the telephoto end. It achieves high optical performance.
• However, the configuration in which the first lens group, which is large and has a large mass, is moved, as in the wide-angle zoom lens described in Patent Document 1, complicates the movement mechanism and is disadvantageous from the viewpoint of miniaturization and weight reduction.
• The present invention provides a negative lead type wide-angle zoom lens that is compact and lightweight, yet has high optical performance over the entire zoom range.

Example 1

• Focal length: 12.42-29.07
• F value: 4.10-6.40
• Half angle of view: 47.72-25.17
• Image height: 11.37-13.66
• Total length: 82.97
• Back focus: 12.29

Example 2

• Focal length: 14.40-29.10
• F value: 4.10-6.29
• Half angle of view: 43.40-25.14
• Image height: 11.46-13.17
• Total length: 75.06
• Back focus: 11.78

Example 3

• Focal length: 20.60-39.00
• F value: 4.10
• Half angle of view: 46.40-29.01
• Image height: 17.94-20.74
• Total length: 97.01
• Back focus: 12.68

Example 4

• Focal length: 20.60-48.50
• F value: 4.10-5.88
• Half angle of view: 46.40-24.04
• Image height: 18.22-21.64
• Total length: 106.52
• Back focus: 19.41

More Canon patents are listed here.

[via asobinet]