Some new Sigma telephoto patents have been found. You can check them out below:
- JP 2023-170
- [Publication date] 2023-01-04
- [Title of Invention] Imaging Optical System
- [Application date] 2021-06-17
- [Applicant]
[Identification number] 000131326
[Name] Sigma Corporation - Kind Code: A1 To provide an imaging optical system suitable for a compact and lightweight telephoto lens by having a compact and lightweight imaging optical system and a compact and lightweight focusing unit.
- 2. Description of the Related Art
Conventionally, as an imaging optical system suitable for a long focal length photographing lens (hereinafter referred to as a telephoto lens), a positive power lens group and a negative power lens are arranged in order from the object side to the image side. A telephoto type imaging optical system with a group arrangement is known. By adopting a telephoto type power arrangement, it is possible to shorten the overall optical length of a telephoto lens, which tends to be long and heavy. - [0003]
Telephoto lenses are often used for photographing sports and animals, and high-speed autofocus is required. Telephoto lenses often use the inner focus method because if the entire telephoto lens moves the entire imaging optical system for focusing, the weight of the lens that moves during focusing increases, making it difficult to achieve high-speed autofocus. . - [0004]
Furthermore, in recent years, the use of a telephoto lens for video shooting has increased. When used in moving image shooting, autofocus often uses a contrast detection method. In the contrast detection method, it is common to cause the focusing unit to wobbling in order to detect the contrast. - [0005]
In addition, in recent years, along with the popularization of compactly designed mirrorless cameras, telephoto lenses are also required to be compact and lightweight. In order to reduce the size and weight of the telephoto lens, it is important to reduce the size and weight of the moving part in addition to reducing the size of the imaging optical system. This is because the size and arrangement of the actuator depend on the size and weight of the movable portion. - [0008]
The present invention has been made in view of such circumstances, and the imaging optical system itself is compact and lightweight, and has a compact and lightweight focusing unit, so that the imaging optical system is suitable for a compact and lightweight telephoto lens. The purpose is to provide a system.
Example 1
- Focal length: 485.00
- F-value: 5.83
- Angle of view: 5.06
- Image height: 21.63
- Overall length: 253.13
Example 5
- Focal length: 700.00
- F-value: 7.97
- Angle of view: 3.52
- Image height: 21.63
- Total length: 318.72
Example 6
- Focal length: 400.00
- F-value: 5.06
- Angle of view: 6.14
- Image height: 21.63
- Overall length: 233.14
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