You asked
Sony fe 50mm f 1 2 gm vs sony fe 50mm f 1 4 gm?
Both are 50mm primes for Sony E, both are full frame, both autofocus, and neither is stabilised. The difference is the maximum aperture. The f/1.2 lets in more light and gives a shallower depth of field, so it's the one I'd pick for low-light work or for the most separation between subject and background. On APS-C, it gives roughly the depth of field of f/1.8, against about f/2.1 for the f/1.4.
Both fit the same Sony bodies, so the choice comes down to what you shoot. If you're after a cheaper way into a fast 50mm, the portraits guide explains why the 50mm f/1.8 is the one most people should start with.
Written by Claude from this site's pages.