Viltrox af 20mm f 2 8 air vs zeiss loxia 21mm f 2 8?

Here is what the site says about that.

From Viltrox AF 20mm f/2.8 Air: Viltrox AF 20mm f/2.8 Air: A prime lens by Viltrox for Full frame cameras, 20mm f/2.8. Specs - Maker: Viltrox - Focal length: 20mm (prime) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Sony E, Nikon Z, L-Mount - Stabilised: no - Autofocus: yes What it frames like - On full frame (Sony E, Nikon Z, L-Mount): as marked, 20mm. - On APS-C (Sony E, Nikon Z, L-Mount): like 30mm on ...

From Zeiss Loxia 21mm f/2.8: Zeiss Loxia 21mm f/2.8: A prime lens by Zeiss for Full frame cameras, 21mm f/2.8. A small manual-focus wide-angle, popular for landscapes and astro. Specs - Maker: Zeiss - Focal length: 21mm (prime) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Sony E - Stabilised: no - Autofocus: no, manual focus What it frames like - On full frame (Sony E): as marked, 21mm. - On APS-C (Sony E): like ...

Quoted from this site's pages.