Sigma 24-40mm f/1.8, 28-45mm f/1.8, and 30-50mm f/1.8

• 4 months ago

Patents were found for Sigma 24-40mm f/1.8, 28-45mm f/1.8, and 30-50mm f/1.8 lenses. You can check out the patent below:

overview

• [Publication number] P2025116419
• [Release date] 2025-08-08
• [Name of invention] Zoom lens
• [Application date] 2024-01-29
• [Applicant]
  
  [Identification number] 000131326
  
  [Name or company name] Sigma Corporation
• To provide a zoom lens that has a large aperture ratio but a reduced overall length, has little center of gravity movement during zooming and focusing, is capable of quiet autofocusing, and is suitable for video shooting.
• [Background Art]
  
  [0002]
  
  In recent years, video shooting using interchangeable lens cameras has become common. To ensure smooth video shooting, it is desirable for the center of gravity in the lens to move as little as possible during zooming and focusing. Furthermore, since a loud motor drive noise during autofocusing can potentially be picked up by the audio recording, it is also important to enable quiet autofocusing.
• [0003]
  
  As interchangeable lenses for single-lens cameras, large-aperture zoom lenses with bright maximum apertures are popular because they combine the convenience of a zoom lens with the characteristics of a bright maximum aperture. In addition, large-format cameras, which have large sensor sizes and excellent image quality, have become popular in recent years, and large-aperture zoom lenses compatible with large-format cameras are in demand.
• [0004]
  
  Examples of zoom lenses with a large aperture ratio include the zoom lenses disclosed in the following patent documents.
• [0006]
  
  Patent Document 1 discloses a negative-lead type large-aperture zoom lens with a maximum aperture of approximately F2.8. However, the focus lens group is heavy and contains many lenses, making it difficult to achieve fast and quiet autofocus. In addition, the overall length of the optical system is long, and aiming for an even larger aperture ratio would result in a huge zoom lens, which is not realistic.
• [0008]
  
  The present invention has been made in consideration of the above circumstances, and aims to provide a zoom lens that has a large aperture ratio but a reduced overall length, has little movement of the center of gravity during zooming and focusing, is capable of quiet autofocusing, and is suitable for video shooting.

Example 1

• Focal length: 28.84-43.66
• F-number: 1.86
• Angle of view: 75.19-50.51
• Image height: 21.63
• Total length: 168.66

Example 2

• Focal length: 24.72-38.82
• F-number: 1.86
• Angle of view: 85.45-55.91
• Image height: 21.63
• Total length: 164.03

Example 3

• Focal length: 30.88-48.48
• F-number: 1.86
• Angle of view: 73.11-46.05
• Image height: 21.63
• Back focal length: 174.77

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