— the lens has an autofocus drive of the "screwdriver" type. Such lenses do not have their own autofocus motor — only a socket for docking with the camera; the motor is placed in the chamber. The main advantages of "screwdrivers" are small weight and dimensions; in terms of speed, they lose somewhat to ultrasonic drives, but they are quite comparable with conventional motors (and sometimes even surpass them). On the other hand, not all cameras with interchangeable lenses have a “screwdriver” drive, and in its absence, autofocus will not be available for such a lens.
