At 17mm, central sharpness is outstanding from f/2.8 through to f/8, excellent at f/11, very good at f/16 and good at f/22. The edges are excellent at f/2.8, outstanding at f/4, excellent at f/5.6 ...

Central sharpness is excellent from f/2.8 all the way through to f/16, and is still very good at f/22. The edges are excellent from f/2.8 to f/8 and very good from f/11 to f/22. This is a very ...