Viltrox sent me this out for review. It's a very reasonably priced alternative to Canon's own brand lenses. I'm not sure how Viltrox have been able to reverse engineer the mount but it works great, most of the time! I did have a few 'communication glitches' that involved restarting the camera but overall, the lens worked great. So, if you want a bright, sharp lens for your Canon RF mount, then look no further than the Viltrox RF 85mm.