Speed sa - bo control control equipment null of shear

摘要

PURPOSE:To permit arbitrary combination of an aperture diameter and exposing time at the time of exposure control by setting the value of a speed command signal at substantially 0 at an arbitrary timing during opening action, thereby stopping a shutter vane in common use as an aperture vane at an arbitrary position. CONSTITUTION:The shutter vane 13 acts to open when the rotating speed of a servo motor M is set at a positive speed. The vane acts to maintain an F value when the rotating speed of the motor M is set at 0 and the vane 13 acts to close when the rotating speed of the motor M is set at a negative speed. The value of the speed command signal is set at substantially 0 at the optional timing during the opening action, by which the vane 13 in common use as the aperture vane is stopped at a specified aperture diameter. The speed command signal is gently varied at the time when the vane 13 shifts from the opening action to a stop action. The exposure control at an arbitrary combination of the aperture diameter and exposing time is thereby permitted.