- Aug 29, 2020
Yes, but don't forget the new electronics. The new mount has been a good moment to get them up to date.The solid technical reason is the shorter flange focal distance. It's 20mm for RF, 44mm for EF.
Untill the R mount was introduced. Now You can use those old lenses with an adapter again.. So, in 1987, Canon rendered all of its existing lenses obsolete.