Northlight has uncovered a USPTO patent showcasing some telephoto zoom lenses for the RF mount. These lens designs appear to be fairly simple and might suggest they’re not L zooms.
The Canon EOS R system will obviously need some less expensive glass, and announcing a non-L RF 70-300 alongside an entry-level EOS R system camera would make a lot of sense.
Optical formulas included in this patent:
RF 70-300mm f/4-5.6
RF 100-400mm f/4-5.6
RF 50-240mm f/4-5.6
I’d wager on the RF 70-300mm f/4-5.6 being a non-L telephoto zoom that will hit the market for the RF mount. I think Canon would keep the RF 100-400mm for an L zoom down the road.