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.