Sigma has filed some patents for some interesting Full frame and APS-C lenses which you can check out below:
Full Frame
Overview
- [Publication number] P2024011707
- [Release date] 2024-01-25
- [Application date] 2022-07-15
- [Name of the invention] Optical system
- [Applicant]
[Identification number] 000131326
[Name] Sigma Co., Ltd. - The present invention provides an optical system that achieves weight reduction while correcting various aberrations such as chromatic aberration by appropriately using glass materials for lenses constituting each lens group.
- BACKGROUND ART
[0002]
In recent years, with the increase in the number of pixels in digital cameras and the like, it has become necessary to strictly correct various aberrations in optical systems used in imaging devices, projection devices, and the like. - [0005]
However, the above-mentioned conventional technology has the following problems. - [0006]
Patent Document 1 proposes a variable magnification optical system that has a wide field of view at the wide-angle end and suppresses axial chromatic aberration by using a special low dispersion glass equivalent to HOYA’s FCD1. There is. However, the optical system described in Patent Document 1 has a problem in that it does not sufficiently correct lateral chromatic aberration, especially at the wide-angle end. - [0007]
Furthermore, Patent Document 2 proposes an optical system that suppresses longitudinal chromatic aberration while having a wide angle of view. However, the optical system described in Patent Document 2 has a problem in that color flare tends to remain due to a shift in the imaging point in the optical axis direction from the C line to the F line from the intermediate angle of view to the periphery of the screen. - [0008]
Furthermore, Patent Document 3 proposes an optical system in which longitudinal chromatic aberration is suppressed by using a special low dispersion glass equivalent to calcium fluoride. However, the optical system described in Patent Document 3 has a problem in that the lateral chromatic aberration from the g-line to the h-line is not sufficiently corrected. - [0009]
Furthermore, Patent Document 4 proposes a variable magnification optical system that suppresses axial chromatic aberration at the telephoto end by using a special low dispersion glass equivalent to HOYA’s FCD1. However, the variable magnification optical system described in Patent Document 4 has a problem in that it does not sufficiently correct longitudinal chromatic aberration at the wide-angle end, and does not sufficiently correct lateral chromatic aberration at the telephoto end. - [0010]
The present invention has been made in view of at least one of these problems, and aims to provide an optical system that corrects various aberrations such as chromatic aberration by appropriately using lens materials. shall be.
Example 1
- Focal length: 28.90-67.75
- F value: 2.07
- Angle of view: 76.74-33.8
- Image height: 21.64
- Total length: 169.15-184.16
Example 2
- Focal length: 12.40-23.15
- F value: 2.92
- Angle of view: 122.82-84.4
- Image height: 21.63
- Total length: 148.00-141.41
Example 3
- Focal length: 14.47
- F value: 2.07
- Angle of view: 114.30
- Image height: 21.63
- Total length: 128.00
Example 5
- Focal length: 154.50-577.80
- F value: 5.16-6.49
- Angle of view: 15.68-4.18
- Image height: 21.63
- Total length: 280.00-380.00
Example 6
- Focal length: 388.00
- F value: 2.88
- Angle of view: 6.32
- Image height: 21.63
- Total length: 330.00
Example 7
- Focal length: 131.00
- F value: 1.85
- Half angle of view: 18.04
- Image height: 21.63
- Total length: 129.50
APS-C
Overview
- [Publication number] P2024011096
- [Release date] 2024-01-25
- [Name of the invention] Imaging optical system
- [Application date] 2022-07-14
- [Applicant]
[Identification number] 000131326
[Name] Sigma Co., Ltd. - [Problem] Suitable for mirrorless digital cameras and video lenses, with the refractive power of each group appropriately arranged to effectively correct various aberrations, angle of view exceeding 100 degrees, and F-number. We provide a retrofocus type wide-angle lens with a large aperture ratio that is bright and has an aperture ratio of less than 2.0.
- BACKGROUND ART
[0002]
As a wide-angle lens, a retrofocus type imaging optical system is known in which a negative lens group is arranged on the object side and a positive lens group is arranged on the image side. Retrofocus type imaging optical systems can easily ensure back focus relative to the focal length, and are widely adopted as optical systems used in imaging devices such as digital cameras and video cameras. - [0012]
The present invention is suitable for mirrorless digital cameras and video lenses, in which various aberrations are well corrected by appropriately arranging the refractive power of each group, and the angle of view exceeds 100 degrees. , a retrofocus type wide-angle lens with a large aperture ratio, which is bright with an F value of less than 2.0.
Example 1
- Focal length: 14.44
- F value: 1.44
- Angle of view: 115.23
- Image height: 21.63
- Total length: 155.19
Example 3
- Focal length: 14.44
- F value: 1.85
- Angle of view: 114.58
- Image height: 21.63
- Total length: 130.82
Example 4
- Focal length: 12.36
- F value: 1.44
- Half angle of view: 122.40
- Image height: 21.63
- Total length: 154.98
Example 5
- Focal length: 10.30
- F value: 1.47
- Half angle of view: 108.80
- Image height: 14.20
- Total length: 111.32
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