Canon has filed a new lens patent for 400mm F/5.6 MIRROR (Catadioptric) Lens, and this could be an EF-M mount lens.
The blue bits are mirrors. The light comes in through L1, bounces off M1/M2 and through a hole in M1 back to the camera.
Take a look at the patent details below:
- Focal length: 400mm
- Aperture: f/5.6
- 2 ω: 1.96
- Image height: 13.66mm
- Back focus: 33.07mm
- Lens length: 247.73mm