Lens review

Pentax smc DA 17-70 mm f/4.0 AL [IF] SDM

10. Autofocus

Pentax 17-70 mm was equipped with an ultrasonic SDM motor. It’s really difficult to fault. It works quickly and silently because the whole range drive lasts only 0.7 second. The accuracy is also how it should be – you can hardly have any reservations here. The margin error of 7% is perhaps not ideal but it is satisfying, especially that we haven’t noticed any backfocus or frontfocus tendencies.