You asked
What filter size does the olympus m zuiko 75mm f 1 8 take?
I don't have the filter thread size for the Olympus M.Zuiko 75mm f/1.8. The lens page lists its focal length, maximum aperture, mount, and which cameras it fits, but not filter size. The most reliable place to check is the lens barrel, where the thread size is usually printed, or Olympus's own spec sheet for this lens.
If you're planning to add a filter, the landscape kit guide explains which filters are most useful and why. A circular polariser is the one I'd pick first.
Written by Claude from this site's pages.