Canon Patent: RF 9-18mm f/4 And RF 10-18mm f/4 Lenses

Another Canon patent application that was published yesterday.

Canon patent application 2023099389 (Japan, published 7/13/2023) discusses optical formulas and methods for two ultra wide zoom lenses.

From the patent literature:

A compact and lightweight zoom lens that has a wide angle of view and high optical performance over the entire zoom range is provided.

Description of the Related Art

In recent years, zoom lenses used in imaging apparatuses are required to have a wide angle of view and high optical performance as imaging apparatuses have become more sophisticated. Further, as a zoom lens having a wide angle of view at the wide-angle end, a negative lead type zoom lens in which a lens group having a negative refractive power precedes the zoom lens is known.
However, in the zoom lens disclosed in Patent Document 1, the focal length of the first lens group is set to be small in order to widen the angle of view. . In addition, the back focus and the refractive power of the first lens group are not appropriate, and it is difficult to further reduce the diameter of the front lens and shorten the total length. The zoom lens disclosed in Patent Document 2 has a short back focus and a refractive power arrangement suitable for shortening the total length. However, the lens groups succeeding the first lens group all have positive refractive power, and it is difficult to narrow the position of the front principal point toward the first lens group when viewed as the entire succeeding group. is difficult.
In order to obtain a compact and lightweight zoom lens that has high optical performance over the entire zoom range while achieving a wide angle, the refractive power and lens configuration of the first lens group, and the lens groups following the first lens group It is important to set the refracting power and placement position of the lens appropriately.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a compact and lightweight zoom lens that has a wide angle of view and high optical performance over the entire zoom range, and an imaging apparatus having the zoom lens.

Example 1

• Focal length: 9.27-17.46
• F-value: 4.12
• Half angle of view: 63.98-51.10
• Image height: 19.00-21.64
• Overall length: 108.47-100.80
• Back focus: 15.71-23.00

Example 2

• Focal length: 10.01-17.46
• F-value: 4.12
• Half angle of view: 62.21-51.10
• Image height: 19.00-21.64
• Overall length: 106.74-99.55
• Back focus: 12.36

More Canon patents are listed here.

[via asobinet]