a method for automatically rewinding the film in a camera having a battery - powered automatic film rewinder , including a motor , a microprocessor , a control circuit , a timer , a microswitch associated with a film frame counter and a microswitch associated with a sprocket . the method comprises the steps of : determining from the time being taken to advance a single frame of film , whether a first film winding abnormality is occurring ; determining whether the abnormality is caused by a deterioration in the power source for the automatic film winding mechanism ; determining from the time being taken to advance a single frame of film , whether a second film winding abnormality is occurring ; determining whether the second winding abnormality is occurring coincidentally with the film being in the vicinity of the last frame of film on the film roll ; and rewinding the film only upon determining that the second film winding abnormality is occurring coincidentally with the last frame of exposed film being in the vicinity of the last frame of film on the film roll .