You asked
What are the alternatives to the olympus m zuiko 25mm f 1 8?
If you want the same 50mm-equivalent view on Micro Four Thirds, the closest swap is the Olympus M.Zuiko 25mm f/1.2 PRO. It's a weather-sealed f/1.2 prime with the same focal length, so it's the one to pick if you shoot in low light or want more background blur and don't mind the extra cost.
If you'd rather have flexibility than a fixed focal length, the Olympus M.Zuiko 8-25mm f/4 PRO zoom covers wide angles through to a 50mm-equivalent view. It's slower at f/4, so it suits daylight and travel better than dim rooms.
Both are Micro Four Thirds lenses. For a general sense of why a 50mm-style view works for people and everyday shooting, see lenses.
Written by Claude from this site's pages.