I took this from the Avon Kennett canal right across the fair city of Bath with the Fuji XF 55-200, and I swear that 164mm is not even this lens' sharpest focal length.

Unless I'm deliberately going for isolating the subject, I usually shoot at f11 with this lens for max IQ (truly). It has worked even better since the last update to firmware of both the lens and my XT-1 body.