You asked
Is the fujifilm xf 18 120mm f 4 lm pz wr good for portraits?
It's a useful all-rounder for portraits, but it isn't a portrait lens. On Fujifilm X bodies it frames like 27-180mm on full frame, so the 120mm end gives you a flattering, compressed view for tight headshots from a comfortable distance.
The drawbacks are the f/4 maximum aperture and the lack of stabilisation. You'll get less background blur than with a faster lens, and you'll be working at higher ISO indoors. If portraits are your main subject, a faster prime will serve you better. The Portraits guide explains which focal lengths to aim for and why.
Written by Claude from this site's pages.