At £460, the Sony DT 16-80mm is certainly not cheap, although we can't figure out why. It has a focus scale viewable through a window on the barrel, but it doesn't have the swift focusing of Canon's USM or Nikon's Silent Wave motors.
Instead, you get a conventional mechanism that's sluggish and noisy. The front element doesn't rotate but there's no manual override of autofocus.
Sony waxes lyrical about the aspherical elements for 'high picture quality across the entire zoom range' but this was in fact a pretty soft lens. Contrast was merely average and there was vignetting when shooting wide-open at the wide-angle end, as well as barrel distortion.