Is the viltrox af 50mm f 2 air worth buying used?

Here is what the site says about that.

From Viltrox AF 50mm f/2 Air: Viltrox AF 50mm f/2 Air: A prime lens by Viltrox for Full frame cameras, 50mm f/2. Specs - Maker: Viltrox - Focal length: 50mm (prime) - Maximum aperture: f/2 - 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, 50mm. - On APS-C (Sony E, Nikon Z, L-Mount): like 75mm on ...

From Viltrox AF 40mm f/2.5 Air: Viltrox AF 40mm f/2.5 Air: A prime lens by Viltrox for Full frame cameras, 40mm f/2.5.

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