You asked
Best wide angle lens for the fujifilm gfx 50r?
For wide angles on the GFX 50R, I'd start with the Fujifilm GF 20-35mm f/4 R WR. It covers 16-28mm full-frame equivalent in one weather-resistant zoom, so it's my everyday pick.
If you want to go wider and faster, the Fujifilm GF 19-35mm T3.5 PZ OIS WR reaches 15-28mm equivalent and has optical stabilisation. That matters, because the GFX 50R body has none.
For a prime, the Laowa 19mm f/2.8 Zero-D GFX gives about 15mm equivalent. If you want the widest view on the list, the Laowa 17mm f/4 Zero-D GFX goes to 13mm equivalent.
To check any other focal length, use the focal length converter.
Written by Claude from this site's pages.