How should the flange distance help a telephoto lens to become shorter?Still, like many were hoping for the superteles to take advantage of the RF mount, maybe bit lighter, shorter and a control ring.
But I guess that's asking for too much. And no cripple hammer. Too much?
You can design a telephoto lens as short as you want to make it based on lens technology without any restrictions for a DSLR, so the RF version will be just the distance longer you know from the RF-EF adapter.
The 300 and 500 lenses have to do the Gen II step, possibly add on DO design (500 F4??)