Patents were found for a Sigma 200mm F2 OS and a Sigma 300mm F2.8 OS.
overview
- [Publication number] P2025162727
- [Release date] 2025-10-28
- [Title of Invention] Imaging optical system
- [Application date] 2024-04-16
- [Applicant]
[Identification number] 000131326
[Name or company name] Sigma Corporation - An imaging optical system is provided that is lightweight, has excellent correction for longitudinal chromatic aberration, and is suitable for a large aperture ratio telephoto lens.
- [Background Art]
[0002]
In recent years, digital cameras have become lighter due to the shift to mirrorless cameras, and imaging devices have become more highly pixelated. Therefore, there is a demand for lighter and more powerful imaging optical systems. - [0003]
In particular, in large-aperture telephoto lenses with long focal lengths and large aperture ratios, the weight of the imaging optical system tends to increase due to the large effective aperture and the large diameter of the lenses arranged on the object side, and therefore further weight reduction is desired. One method for reducing the weight of large-aperture telephoto lenses is to reduce the number of lenses with large effective diameters arranged on the object side. - [0004]
Furthermore, in large aperture ratio telephoto lenses, axial chromatic aberration is likely to occur due to the generally long focal length and large aperture ratio. It is known that increasing the number of lenses arranged on the object side is an effective way to correct axial chromatic aberration. - [0007]
The present invention has been made in consideration of the above circumstances, and its object is to provide an imaging optical system suitable for a telephoto lens with a large aperture ratio, which is lightweight and has well-corrected axial chromatic aberration. - [0058]
The vibration reduction group Gos moves in a direction including a component perpendicular to the optical axis so as to reduce image blur caused by shaking of the imaging optical system.
Example 1
- Focal length: 194.30
- F-number: 2.07
- Angle of view: 12.45
- Image height: 21.63
- Total length: 212.00
- Back focal length: 22.4456
Example 3
- Focal length: 290.30
- F-number: 2.90
- Angle of view: 8.35
- Image height: 21.63
- Total length: 286.83
- Back focus: 29.5555
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