Nikon z 400mm f 2 8 tc vr s vs nikon z 600mm f 4 tc vr s?

Here is what the site says about that.

From Nikon Z 400mm f/2.8 TC VR S: Nikon Z 400mm f/2.8 TC VR S: A prime lens by Nikon for Full frame cameras, 400mm f/2.8. A pro sports lens with a built-in 1.4x teleconverter. Specs - Maker: Nikon - Focal length: 400mm (prime) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Nikon Z - Stabilised: yes - Autofocus: yes What it frames like - On full frame (Nikon Z): as marked, 400mm. - On APS-C (Nikon Z): like 600mm on ...

From Nikon Z 600mm f/4 TC VR S: Nikon Z 600mm f/4 TC VR S: A prime lens by Nikon for Full frame cameras, 600mm f/4. A pro wildlife lens with a built-in 1.4x teleconverter. Specs - Maker: Nikon - Focal length: 600mm (prime) - Maximum aperture: f/4 - Made for: Full frame sensors - Mounts: Nikon Z - Stabilised: yes - Autofocus: yes What it frames like - On full frame (Nikon Z): as marked, 600mm. - On APS-C (Nikon Z): like 900mm on ...

Quoted from this site's pages.