A lens unit consists of a plurality of lens frames, a stepping motor, and a driving control unit. The plurality of lens frames for holding an imaging optical system lies in a lens barrel and moves over a stowage interval and a zoom interval. The stowage interval is an interval between a position of stowage...http://www.google.de/patents/US7489358?utm_source=gb-gplus-sharePatent US7489358 - Lens device for a camera with a stepping motor drive optimized for speed and power saving
