Steuervorrichtung für die Bildvergrösserung einer Kamera

A lens focusing system for a camera, comprising a focusing lens movable within a predetermined range having two ends, means for determining an amount required to move said focusing lens to obtain an in-focus condition, and means for driving said focusing lens in response to said determined amount to position said focusing lens at said in-focus condition. Furthermore there is a means provided for generating a plurality of drive signals in response to said driving of said focusing lens and a means for monitoring said plurality of drive signals. Additional there is a means for establishing a monitored position value based upon said monitored plurality of drive signals as far as a means for comparing said monitored position value with a predetermined position value corresponding to one of said ends of said range after said lens has been moved by said determined amount. Driving means are driving said focusing lens furthermore in a direction in which it has been driven, if said monitored position value corresponds to a position which is out of said predetermined range, until said focusing lens reaches said one end out of said predetermined range. Further means is provided for replacing said monitored position value with said predetermined position value when the focusing lens has reached said one end of said predetermined range.