You asked
Olympus m zuiko 75mm f 1 8 vs panasonic lumix g 42 5mm f 1 7?
The two lenses fit the same Micro Four Thirds bodies, so the choice comes down to framing and stabilisation.
The Olympus M.Zuiko 75mm f/1.8 frames like 150mm on full frame. It has more reach, which suits tighter headshots and subjects you can't approach, but it isn't stabilised.
The Panasonic Lumix G 42.5mm f/1.7 frames like 85mm on full frame, the classic portrait view. It's stabilised, so it's the one I'd pick for everyday use, street, and handheld shooting in low light.
If you mostly photograph people at a comfortable distance, start with the 42.5mm. If you want more reach and don't mind carrying a bit more distance, get the 75mm. The portraits guide explains why longer lenses flatter faces.
Written by Claude from this site's pages.