Sigma 65mm F1.4 DG DN and Sigma 50-135mm f/2.8 DC DN APS-C Patents Found
A Sigma 50-135mm F2.8 DC DN and Sigma 65mm F1.4 DG DN patents were found by asobinet and while most patents do not become lenses the Sigma 50-135mm F2.8 DC DN could be a useful 3rd party 70-200mm full frame equivalent lens to compliment the popular Sigma 18-50mm f/2.8 DC DN Contemporary.
Sigma 50-135mm f/2.8 DC DN Overview
- [Publication number] P2023179307
- [Release date] 2023-12-19
- [Name of the invention] Imaging optical system
- [Application date] 2022-06-07
- [Applicant]
[Identification number] 000131326
[Name or name] Sigma Co., Ltd.
- An object of the present invention is to provide an imaging optical system that is equipped with an image stabilization mechanism, has a small open F value over the entire zoom range, and has achieved miniaturization.
- [Background technology]
【0002】
In recent years, so-called mirrorless cameras have become popular, which do not include a quick return mirror that is placed between an imaging optical system and an image sensor and guides light to a finder optical system.
- 【0003】
Mirrorless cameras have smaller casings due to the elimination of mirrors, and as a result, there is a need for smaller imaging optical systems. Additionally, there is a demand for a large-diameter zoom lens that is equipped with an image stabilization mechanism and has a small aperture F value over the entire zoom range.
- 【0005】
Patent Document 1 discloses a positive lead type zoom lens that has a bright open F value of about 2.8 and in which the lens group closest to the object side is fixed to the image plane during zooming. The zoom lens disclosed in Patent Document 1 has the advantage of high convenience and robustness because the total optical length does not change, but there is a problem that the size of the imaging optical system is large.
- 【0006】
Patent Document 2 discloses a positive lead type zoom lens that has a bright open F value of about 2.8 and has a shortened overall optical length at the wide-angle end. In the zoom lens disclosed in Patent Document 2, many lens groups with large diameters that move during zooming are arranged on the image side of the aperture stop, so the mechanism required for zooming becomes large and the lens barrel is There is a problem that the size in the radial direction is large.
- 【0007】
The present invention has been made in view of these circumstances, and it is an object of the present invention to provide an imaging optical system that is equipped with an image stabilization mechanism, has a small open F value over the entire zoom range, and is miniaturized.
Example 1
- Focal length: 51.50-132.00
- F value: 2.92
- Angle of view: 31.56-12.01
- Image height: 14.20
- Total length: 130.00-154.13
Sigma 65mm F1.4 DG DN Overview
- [Publication number] P2023179306
- [Release date] 2023-12-19
- [Name of the invention] Single focus lens
- [Application date] 2022-06-07
- [Applicant]
[Identification number] 000131326
[Name] Sigma Co., Ltd.
- An object of the present invention is to provide a single focal length lens that has a large aperture ratio of about F1.4 and can perform quick autofocus, with various aberrations well corrected.
- [Background Art]
[0002]
Single focus photographing optical systems used in optical devices such as digital cameras are required to have a large aperture ratio in order to support high-speed shooting and expressions that take advantage of bokeh. . Furthermore, as the pixel density of image pickup devices increases, there is a demand for higher performance by further correcting various aberrations. Conventionally, imaging optical systems for single-lens reflex cameras often use a retrofocus type because it is necessary to ensure a back focus within the movable range of the mirror. Photographic lenses that adopt a retrofocus type with a long back focus, large aperture ratio, and high performance are known.
- [0004]
Patent Document 1 discloses an example in which a double Gauss type lens configuration, which has been widely adopted in lenses with a standard angle of view, has a lens configuration on the object side that functions as a wide converter consisting of a concave lens and a convex lens component. There is. This optical system achieves a large aperture ratio with an FNO of about 1.4. However, the aberration correction mainly in the sagittal direction is insufficient, and the image spread is large at the high portion of the peripheral image. Similar to Patent Document 1, Patent Document 2 discloses an optical system having a double Gauss type lens configuration on the object side that functions as a wide converter. Although this optical system increases the number of lenses that make up the lens group that plays the role of a wide converter and allows for closer-up photography than in Patent Document 1, the aberration correction in the sagittal direction is insufficient and the image in the high part of the peripheral image is The spread is large. In Patent Document 3, a new lens component with a convex surface on the object side is added immediately after the image side of the aperture stop to solve the sagittal direction aberration caused by the double Gauss type, which was a problem in Patent Documents 1 and 2. This effectively compensates. Furthermore, when focusing from an object at infinity to an object at a short distance, quick autofocus is possible by moving only the second lens group toward the object. However, it cannot be said that astigmatism and field curvature are sufficiently optimized over the entire shooting distance.
- [0005]
The present invention was made in view of this situation, and provides a single focal length lens that has a large aperture ratio of about F1.4, allows quick autofocus, and has well corrected various aberrations over the entire shooting distance. The purpose is to provide.
Example 1
- Focal length: 63.22
- F value: 1.46
- Angle of view: 1.46
- Image height: 21.63
- Total length: 173.02
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