See my Fujifilm GFX wish list.
This scene tests the Fujifilm GF 23mm f/4 on the most demanding target I know of: a finely detailed geometrically planar subject at distance. Such a scene is unforgiving of focus shift or field curvature or any lens symmetry defects. It is particularly difficult for an extreme wide angle lens.
Includes images up to full resolution from f/4 - f/9.
Performance of the Fujifilm GF 23mm f/4 surely ranks among the finest performances available in the 19mm (equivalent) focal length range in terms of total image sharpness and consistency across the field. Accordingly, I have only minor reservations in giving my highest recommendation to the about $2600 Fujifilm GF 23mm f/4—this is the wide angle lens that anchors the system, along with the about $2800 Fujifilm GF 110mm f/2 at the long end.