Interchangeable Objectives for a Reflex Camera

摘要

1,199,056. Reflex cameras with interchangeable objectives. ASAHI KOGAKU KOGYO K.K. July 26, 1967 [July 30, 1966], No.34423/67. Heading G2A. A single lens reflex camera has an exposure control system which includes a photo-sensitive element 8, the camera being provided with one or more interchangeable objectives 1 each having a diaphragm and a diaphragm setting member 2 carrying a member 3 in a position representative of the output of the element 8 when the objective is attached to the camera with the diaphragm fully open and placed before a reference light source, the system also including a slider 6 engageable by the setting member 3 upon attachment of the interchangeable objective to the camera. A variable resistor 4 is mounted within the camera body, so when the slider 6 is engaged by the member 3 the resistance is varied. The resistor 4 forms part of an exposure meter circuit including a current source 7, the photo-sensitive element 8, an indicating meter 9 having differential windings 91 and 911, and a variable resistor 10 set in accordance with film sensitivity and shutter speed. Thus the exposure control circuit is corrected by variable resistor 4 for the objective in use.