Abstract: An iris diaphragm device wherein a rocking motion of a movable magnetic member caused by application of a driving electric current corresponding to the brightness of a subject is transmitted to a leaf operating member for opening or closing iris diaphragm leaves through a connecting lever provided at the both end portions thereof with clearances. Because of the clearances, the iris diaphragm leaves open or close in prompt response to the application of the driving electric current and a chattering motion of the movable magnetic member brought about when it stops is completely absorbed, thereby enable a non-flickering exposure.

Abstract: An iris diaphragm device for use in an automatic exposure cameras of various types comprises iris diaphragm leaves which are simultaneously opened or closed by rotational motion of a leaf operating disc and a drive element having a movable magnetic ring of a noncircular shape composed of near segments with pivot pins and remote segments and adapted to rotate the leaf operating disc. The mechanism for pivotally supporting the movable magnetic ring and transmitting the swinging motion of the movable magnetic ring to the leaf operating disc is mounted in the space left outside the near segments of the movable magnetic ring without the smallest strain, thereby preventing the lens barrel of the camera from being increased in size or protruding in part.