Verdict

Overall this is a very capable lens but it is also a costly one. Photographers who genuinely need its f/4 constant maximum aperture and weatherproofing measures will doubtless be willing to invest in a lens of such quality but others may rightly hesitate. More importantly, potential buyers who are using older-generation Pentax digital bodies should definitely check the zoom's performance on their own cameras rather than relying on an in-store test undertaken using a different body.