You asked
What is the fujifilm gf 250mm f 4 r lm ois wr good for?
The Fujifilm GF 250mm f/4 R LM OIS WR is a stabilised telephoto prime. On a Medium format GFX body it frames like about 198mm on full frame, so it suits subjects you can't approach closely: distant wildlife, sport, or architectural details. Its f/4 aperture gives roughly the depth of field of f/3.2 on that format, which helps separate a subject from a busy background.
It also works well for portraits. Longer focal lengths let you stand back and keep faces in natural proportion, as I explain on the Portraits page.
It fits every GFX body in the catalogue, so for a sensible pairing I'd choose the Fujifilm GFX 50S II for stills work or the Fujifilm GFX100 II if you want the most resolution.
Written by Claude from this site's pages.