The Fujinon XF 16mm f/1.4 R WR is classified as a fast wide prime for low-light and reportage use. Its f/1.4 maximum aperture is its marketing specification. Its usefulness for interior architectural photography comes from something else entirely: the 24mm-equivalent field of view combined with the optical quality at f/8, where it delivers a flat field with well-controlled distortion and minimal coma compared to many wide lenses at this equivalent focal length.