You asked
Best camera for the canon rf 75 300mm f 4 5 6?
Here is what the site says about that.
From Canon RF 75-300mm f/4-5.6: Canon RF 75-300mm f/4-5.6: A zoom lens by Canon for Full frame cameras, 75-300mm f/4-5.6. A cheap, light telephoto zoom, but with no optical stabilisation. Specs - Maker: Canon - Focal length: 75-300mm (zoom) - Maximum aperture: f/4-5.6 (it gets darker as you zoom in) - Made for: Full frame sensors - Mounts: Canon RF - Stabilised: no - Autofocus: yes What it frames like - On full frame (Canon RF): as marked, 75-300mm. ...
From Canon EF 75-300mm f/4-5.6 III: Canon EF 75-300mm f/4-5.6 III: A zoom lens by Canon for Full frame cameras, 75-300mm f/4-5.6. A very common cheap telephoto: soft at 300mm and not stabilised.
Quoted from this site's pages.