Interchangeable objective lens diaphragm exposure control coupling mechanism

A mechanism for transmitting the position of a diaphragm ring of a camera interchangeable lens to an exposure control device in the camera interchangeable viewer, a mechanism is mounted on the housing and includes a fixed gear, a mounting arm swingable about the fixed gear and having a sector shaped outer end which supports a rotatable gear which is coupled to the fixed gear by an idler gear carried by the mounting arm. A connector arm has one end connected to and moveable and rotatable with the rotatable gear, and is provided at its outer end with a coupling pin which separably engages a coupling element carried by the diaphragm ring. A flexible line extends from the outer end of the mounting arm along the periphery of the arm sector shaped end to the exposure control device and is spring loaded. The fixed and rotatable gears may be replaced by pulleys coupled by a flexible belt. The end of the connector arm traverses a circular path corresponding to that of the diaphragm ring coupling element.