You asked
Best portrait lens for canon rf?
For Canon RF, my pick is the Canon RF 85mm f/1.4L VCM. It's a full frame prime at 85mm, the classic portrait focal length, and it's lighter than the f/1.2L if you don't want to carry a brick. It was also built with video in mind.
If you'd rather go manual focus and spend less thought on autofocus, the Voigtländer Portrait Heliar 75mm f/1.8 is a full frame option that mounts on Canon RF. On a Canon APS-C body it frames like about 120mm, which still works well for head-and-shoulders shots.
Whichever you choose, remember that light matters more than the lens. Face a window and expose for the face. For more on that, see Portraits.
Written by Claude from this site's pages.