Sigma filed a patent in Japan for 20mm f/1.8 DG HSM Contemporary lens:
- Patent number: 2016-12034
- Published on January 21, 2016
- Filed on June 30, 2014
- Focal length: 20.70 21.01
- F-number: 1.84 1.95
- Full angle of view 2ω: 93.42 90.34
- The image height Y: 21.63 21.63
- Overall length of the lens: 139.73 139.73
Canon has a patent application for a EF 16-35mm f / 2.8 L USM lens.