Sharpness is very good at f/1.8 and f/2, excellent from f/2.8 to f/8 and very good at f/11 and f/16. The edges are good at f/1.8 and f/2, very good from f/2.8 to f/5.6, good at f/8 and f/11 and ...

The Zeiss Batis Distagon 18mm f/2.8 T* lens is priced at £1199. 18mm lenses have always been somewhat rare for full-frame systems, so the only obvious direct alternative is the Samyang 18mm f/2.8 ...