Patents were found for a Canon 28mm F1.2 and 35mm F1.4, which you can read below:
overview
- [Publication number] P2025109405
- [Release date] 2025-07-25
- [Application date] 2024-01-12
- [Applicant]
[Identification number] 000001007
[Name or company name] Canon Inc. - To suppress breathing and fluctuations in optical performance during focusing.
- [Background Art]
[0002]
When a focus lens group is driven in an optical system, a fluctuation in the angle of view, known as breathing, may occur. Patent Document 1 discloses an optical system that employs a so-called floating focus method for driving multiple focus lens groups to reduce the amount of movement of each focus lens group, thereby suppressing the occurrence of breathing. - [0003]
In addition, high optical performance with suppressed aberrations is also required for the optical system. Patent Document 2 discloses an optical system in which a negative focus lens group and a positive focus lens group are moved in different directions to suppress fluctuations in optical performance (various aberrations) during focusing. - [0005]
However, in the optical system of Patent Document 1, the imaging magnification at the shortest imaging distance is small, less than 0.1, and the optical performance, particularly the spherical aberration, varies greatly with zooming. On the other hand, in the optical system of Patent Document 2, breathing during focusing is large. - The present
invention provides an optical system capable of suppressing breathing and fluctuations in optical performance during focusing, and an image pickup apparatus equipped with the optical system.
Example 1
- Focal length: 24.72
- F-number: 1.44
- Half angle of view: 37.03
- Image height: 18.64
- Total length: 117.81
- Back Focus: 17.20
Example 2
- Focal length: 27.62
- F-number: 1.24
- Half angle of view: 34.33
- Image height: 18.86
- Total length: 124.66
- Back focal length: 13.54
Example 3
- Focal length: 24.34
- F-number: 1.80
- Half angle of view: 37.81
- Image height: 18.89
- Total length: 120.16
- Back focal length: 25.58
Example 4
- Focal length: 48.61
- F-number: 1.44
- Half angle of view: 23.99
- Image height: 21.64
- Total length: 129.72
- Back Focus: 15.98
Example 5
- Focal length: 34.00
- F-number: 1.44
- Half angle of view: 30.34
- Image height: 19.90
- Total length: 129.94
- Back Focus: 15.50
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