Originally Posted by Dogman
The 23mm f/2 Fuji WR lens is fully corrected optically, not by the software. At least according to both LensTip.com and Opticallimits.com in their measurements of the lens. The distortion in the two photos posted here is totally due to the tilting of the camera, not any distortion in the lens used.
I am not an expert on lens design or on Fuji lenses. So, for all I know, you may be right.
What I do know is that tilting the camera does not cause undulating lines, like those green subway rails. In all discussions of lens distortion that I have seen, that is exactly what they are talking about -- curved lines that should be straight.