EF - RF Adapter “WORKS EXCELLENT” I am often ask how well does the EF - RF adapters work with the Canon R5, R6, & R3. Well I say it works very well. I wanted to test out my EF 400mm f2.8L III with 1.4x Extender III and use the 1.6x in camera crop which would gave me a focal length of 896mm @ f4. The image quality was amazing and sharp. #canonusa #teamcanon #canoneosr3 #canon_photos #mycanonstory #canonexploreroflight #canonmirrorless #nflphoto