in a single lens reflex camera having a movable mirror , a metering circuit , a circuit for operating a proper exposure value in accordance with the metering output of the metering circuit , a circuit for storing the output of the operation circuit , display means and operating switch means , holding means is provided for holding the output of the memory circuit at a value before the return of the mirror to its normal position for a predetermined period of time after the mirror has returned to its normal position and for applying the held output to the display means .