You asked
Sony e 20mm f 2 8 vs voigtl nder apo lanthar 28mm f 2 aspherical?
Here is what the site says about that.
From Voigtländer APO-Lanthar 28mm f/2 Aspherical: Voigtländer APO-Lanthar 28mm f/2 Aspherical: A prime lens by Voigtländer for Full frame cameras, 28mm f/2. Specs - Maker: Voigtländer - Focal length: 28mm (prime) - Maximum aperture: f/2 - Made for: Full frame sensors - Mounts: Sony E, Nikon Z, Leica M - Stabilised: no - Autofocus: no, manual focus What it frames like - On full frame (Sony E, Nikon Z, Leica M): as marked, 28mm. - On APS-C (Sony E, Nikon Z): ...
From Sony E 20mm f/2.8: Sony E 20mm f/2.8: A prime lens by Sony for APS-C cameras, 20mm f/2.8. Specs - Maker: Sony - Focal length: 20mm (prime) - Maximum aperture: f/2.8 - Made for: APS-C sensors - Mounts: Sony E - Stabilised: no - Autofocus: yes What it frames like - On APS-C (Sony E): like 30mm on full frame; f/2.8 gives about the depth of field of f/4.2 there. - On the larger-sensor bodies of Sony E: ...
Quoted from this site's pages.