Sigma 50-135mm f/2.8 DC DN APS-C Lens Patent Found

December 20, 2023
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Recently we made a recap of all the Sigma and Tamron patented APS-C lenses.

Well, it looks like we have to add another one to the list as spotted by the Japanese website asobinet:

Sigma 50-135mm f/2.8 DC DN

Looking at the patent details, asobinet concludes that aberration is beautifully corrected in the entire zoom area and it has no internal zoom, unlike the Sigma 70-200mm F2.8 DG DN OS full frame lens.

The new patent is very similar to the already patented Sigma 50-140mm f/2.8 DC DN and that was very high on your wishlist when I launched the survey asking you which patented Sigma/Tamron lens you’d like to get.

Patented APS-C lenses by Sigma and Tamron

Patent Details

Summary

[Public number] P2023179307
[Publication date] 2023-12-19
[Name of the invention] Imaging optical system
[Date of application] 2022-06-07
[Applier] [Identification number] 000131326
[Name or name] Sigma Co., Ltd.
[Issue] Equipped with a shake correction mechanism, the open F value is small in the entire zoom area, and provides an imaging optical system that has achieved miniaturization.
[Background technology] [0002] In recent years, so-called mirrorless cameras, which are placed between the imaging optics and the image sensor, have become popular, and have eliminated quick return mirrors that lead light rays to the viewfinder optics.
[0003] Mirrorless cameras have a smaller enclosure due to the abolition of mirrors, so the miniaturization of the imaging optical system is required accordingly. In addition, it is equipped with a hand shake correction mechanism, and a large aperture zoom lens with a small open F value is required throughout the zoom area.
[0005] In patent document 1, the open F value is 2. A positive lead type zoom lens with about 8 bright, the most object-side lens group fixed to the image surface is disclosed. The zoom lens disclosed in Patent Document 1 has the advantage of high convenience and robustness due to the fact that the total length of the optics does not change, but there is a problem that the size of the imaging optical system is large.
[0006] In the patent document 2, the open F value is 2. A positive lead type zoom lens with a shorter optical total length at the wide-angle end, which is about 8 bright, has been disclosed. The zoom lenses disclosed in Patent Document 2 have many lenses with a large diameter that move when changing times rather than the opening aperture, so the mechanism required for variable magnification is larger, and the radial size of the lens barrel is large. Ru.
[0007] This invention is made in view of this situation, and it is equipped with a shake correction mechanism, and aims to provide an imaging optical system that achieves miniaturization with a small open F value in the entire zoom area.

Example 1

Focal length: 51.50-132.00
F value: 2.92
Angle of view: 31.56-12.01
Statue height: 14.20
Total length: 130.00-154.13

Sigma 50-135mm f/2.8 DC DN