You asked
Olympus m zuiko 12 45mm f 4 pro vs panasonic leica dg 12 60mm f 2 8 4?
Both lenses cover the same Micro Four Thirds bodies, so the choice comes down to the lens itself. I'd pick the Panasonic Leica DG 12-60mm f/2.8-4 for most people. It reaches further, roughly 24-120mm on full frame, and it's stabilised, which the Olympus isn't.
The Olympus M.Zuiko 12-45mm f/4 PRO is the steadier option through its whole zoom range, since it stays at f/4 rather than dropping to f/8 at the long end. It frames more tightly on the telephoto side, though, and it has no stabilisation. If you shoot mostly in good light and want that constant f/4, it's a sensible pick.
If you're still choosing your first standard zoom, the lenses guide explains where these fit.
Written by Claude from this site's pages.