Fujifilm X-H1 + Samyang 12mm f/2.0
Here are some example images I shot with the ultra-wide Samyang 12mm on my Fuji X-H1. This lens equates to an 18mm on full frame.
I really love this lens, it is lightweight and compact, and image quality is superb edge-to-edge. Best of all, Samyang were thoughtful enough to provide a filter thread and a removable hood, unlike so many other manufacturers who make it pretty much impossible to use filters on ultra-wides. The filter thread opens up this lens to be a great lens for video when combined with an ND or VND filter.