Just mounted the Canon RF 85m f/1.2L on the Canon EOS R. What a high quality flange on both—notably more solid than the L-mount Leica lenses on the Panasonic S1R which have a slight slop (the Panasonic Lumix S PRO 50/1.4 did not, and one other reader reported the same mount slop with Leica SL lenses).
The Canon RF 85/1.2L is huge and clearly built for performance as the priority—none a trace of the Nikon NIKKOR Z compromises. Canon RF lenses (at least the 50/1.2L, 85/1.2L, 28-70/2) feel like serious pro gear. Not one Nikon NIKKOR Z lens can say the same.
If the Canon RF 50mm f/1.2L is any indication, I expect the 85/1.2L to be the world’s best. But what a boat anchor, as in sheer neck-yanking weight. However lovely the images might be, this is a serious chore to heft this thing.
Still, Canon should deliver a high megapixel mirrorless camera out, imaging performance should prove out Canon’s distinctive “size and weight be damned, it’s the optical quality” strategy. Which might ultimately sway me to Canon once that body arrives.
I also have on hand the Canon RF 28-70mm f/2L and the Canon RF 35mm f/1.8 Macro STM. The 35/1.8 macro ships without the Canon EW-52 lens hood, which is outrageous because the front lens element is right there out in front, quite exposed.