You asked
Nikon z 50mm f 1 4 vs nikon z 50mm f 1 8 s?
The big difference is aperture. The Nikon Z 50mm f/1.4 lets in a little more light and gives a shallower background blur, so it's the one for dim rooms and subjects you want to isolate. On APS-C, its f/1.4 behaves like about f/2.1 for depth of field.
The Nikon Z 50mm f/1.8 S is my pick for most people. It's the same 50mm view, it fits the same Nikon Z bodies, and it's a sensible everyday prime. If you want to know what a 50mm does for people, start with portraits.
Written by Claude from this site's pages.