A patent application displaying the optical system for an EF 10mm f/2.eight prime lens has been filed in Japan.
Japan Patent Application 2018-233223:
- Focal size: 10.30mm
- F quantity: 2.88
- The half angle of view: 64.54°
- Image peak: 21.64mm
- Lens size: 124.58mm
- Back focus: 38.00mm
It seems like this patent might have been part of the EF 11-24mm f/4L USM growth.