Nikon z 20mm f 1 8 s vs viltrox af 20mm f 2 8 air?

Here is what the site says about that.

From Nikon Z 20mm f/1.8 S: Nikon Z 20mm f/1.8 S: A prime lens by Nikon for Full frame cameras, 20mm f/1.8. A fast wide prime, popular for landscapes and night skies. Specs - Maker: Nikon - Focal length: 20mm (prime) - Maximum aperture: f/1.8 - Made for: Full frame sensors - Mounts: Nikon Z - Stabilised: no - Autofocus: yes What it frames like - On full frame (Nikon Z): as marked, 20mm. - On APS-C (Nikon Z): like 30mm ...

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 ...

Quoted from this site's pages.