Canon Patent Application: High Magnification Super Telephoto Zooms

Atypically in patent embodiments, it's usually difficult for super telephoto zoom lens to take full advantage of the RF mount.  One reason is that you simply can't use a Tele extender if the rear elements are sitting too far back in the lens.  Because of this, at times, it's difficult to determine if a patent application is for RF or EF lenses because there's so much room in the rear of the lens from the last element to the sensor plane, that it could be either mount.

These embodiments however show a back focus distance of around 30mm, which would make them more non extender friendly lenses or they could also fit the extender on for only the telephoto part of their zoom, similar to the RF 100-500L.  With a short back focus distance, these embodiments are certainly RF mount only.

Canon RF 60-600mm F4.5-8
Focal length            61.50 164.60 585.00
F number                 4.46   5.94   8.16
Half angle of view (°)  19.38   7.49   2.12
Lens total length      258.90 302.70 346.50
BF                      30.00  49.79  90.50

Canon RF 70-700mm F4.5-F8
Focal length            70.00 185.35 682.00
F number                 4.76   6.20   8.16
Half angle of view (°)  17.18   6.66   1.82
Lens total length      271.00 316.00 361.00
BF                      31.22  50.94  97.50

Japan Patent Application 2022-053697

Laowa announces the 20mm Shift lens for the RF and EF Mounts Canon Announces New Flex Zoom Lens Series CN-E45-135mm T2.4L and CN-E20-50mm T2.4L