Abstract: An APS camera having means for limiting removal and replacement of the film cartridge to those designated to do so. The camera includes an access door to provide access to a film cartridge receiving compartment. A latch disposed on the exterior sidewall of the camera main body, adjacent the film cartridge receiving compartment, secures the access door in the closed position. A lock mechanism, comprising an outer housing and an inner lever disposed within the outer housing, is secured to an exterior sidewall of the camera casing over the latch. The lever is structured for movement from a first blocking position, wherein the latch is inaccessible, to a second open position, wherein the latch may be accessed and the access door opened. The lever includes a pair of outwardly extending locking pins structured for mating engagement with corresponding holes in the housing so as to retain the lever in the first blocking position.