In October of 2018, Canon introduced the EOS-R, the first in a new line of full-frame mirrorless still and video cameras along with a new lens mount, dubbed ‘RF’. Unlike the familiar EF mount, which debuted in 1987 with the original EOS series of film cameras, Canon’s new mirrorless mount provides a greatly reduced flange focal distance — also known as flange depth or registration distance — along with a higher bandwidth data pathway between bodies and lenses.