Canon rf 20mm f 1 4l vcm vs ttartisan 21mm f 1 5 asph?

Here is what the site says about that.

From Canon RF 20mm f/1.4L VCM: Canon RF 20mm f/1.4L VCM: A prime lens by Canon for Full frame cameras, 20mm f/1.4. Specs - Maker: Canon - Focal length: 20mm (prime) - Maximum aperture: f/1.4 - Made for: Full frame sensors - Mounts: Canon RF - Stabilised: no - Autofocus: yes What it frames like - On full frame (Canon RF): as marked, 20mm. - On APS-C (Canon) (Canon RF): like 32mm on full frame; f/1.4 gives about the depth of ...

From TTArtisan 21mm f/1.5 ASPH: TTArtisan 21mm f/1.5 ASPH: A prime lens by TTArtisan for Full frame cameras, 21mm f/1.5. Specs - Maker: TTArtisan - Focal length: 21mm (prime) - Maximum aperture: f/1.5 - Made for: Full frame sensors - Mounts: Sony E, Nikon Z, Canon RF, Leica M - Stabilised: no - Autofocus: no, manual focus What it frames like - On full frame (Sony E, Nikon Z, Canon RF, Leica M): as marked, 21mm. - On APS-C ...

Quoted from this site's pages.