Camera shutter unit having a shutter blade to open and close an exposure aperture

A camera shutter unit, comprising:

• a base plate having an exposure aperture;
• a diaphragm blade arranged to be capable of moving between a stopping-down position wherein the aperture is stopped down and an evacuating position wherein the aperture is opened;
• a shutter blade arranged to be capable of moving between an opening position wherein the aperture is opened and a closing position wherein the aperture is closed;
• and
• a drive-control mechanism for drive-controlling the shutter blade and the diaphragm blade, the drive-control mechanism having a single electromagnetic drive source capable of driving the shutter blade and the diaphragm blade to interlock the diaphragm blade with the shutter blade and a restricting means for restricting movement of the shutter blade toward the closing position when the diaphragm blade is positioned in the stopping-down position and for releasing its restriction by a drive force generated by the electromagnetic drive source,
• wherein the electromagnetic drive source keeps the shutter blade in a way position corresponding to a condition where the diaphragm blade is kept in the stopping-down position via magnetic force while the electromagnetic drive source is non-energized, and the electromagnetic drive source keeps the shutter blade in the opening position with the diaphragm blade in the evacuating position via magnetic force while the electromagnetic drive source is non-energized.