Patent GB-976762-A (GB)
Title: Photographic camera with an exposure value setting device
IPC: G01N29/06
Filed: 1962-01-17
Abstract: 976, 762. Photographic cameras. AGFA A.G. Jan. 17, 1962 [Jan. 17, 1961], No. 1726/62. Addition to 969,334. Heading G2A. In a modification of a photographic camera as claimed in Claim 1 of the parent Specification comprising an automatic exposure value setting device providing optional control programmes in each of which a different predetermined series of shutter speed and diaphragm aperture pairings is available corresponding to the same range of exposure values and including a changeover device for the preselection of the desired control programme, there is provided a common cam member including two cam systems, one for control of the shutter speed setting means and the other for control of the diaphragm aperture setting means, each cam system having angularly spaced cams corresponding to the different control programmes and the common cam member and a housing including the setting means being relatively rotatable, by means of a changeover member coupled to one of them, about an axis on which the cam systems are centred in order to select the desired control programme, the arrangement being such that from each programme setting of the cam member and housing, by means of an automatic exposure value setting device, the one of them that is coupled to the changeover member can be rotated within predetermined limits with respect to the latter to effect exposure value setting within the control programme selected. As shown the changeover member is a disc 419 bearing pins 444a, b, c which engage in slots 443a, b, c in a cam disc 430 to which is pinned a cam disc 431 forming the common cam member. A pin 447 on the disc 419 is connected by a spring 448 to a pin 429c on cam disc 430 so that normally the two cam discs are located against the pin 447. The two multiple section cam discs 430,431 controlling diaphragm aperture and shutter speed settings respectively are rotatable by means of the changeover member disc 419 to bring into operation selectively one of five cam pair combinations. For automatic exposure setting operation in which setting is effected by key 463 and slide 452 under photoelectric control, there are provided three programmes I, II, III selected by setting the member 419 to marks 426a, b, c viz. I first reducing the diaphragm aperture to a minimum and then increasing the shutter speed, using cams 432,438; II increasing the shutter speed at maximum diaphragm aperture and then reducing the aperture, using cams 433, 439; and III simultaneous variation of shutter speed from slowest to fastest with reduction of diaphragm aperture from maximum to minimum using cams 434,440. By setting the changeover member to the bulb marking on scale 427a cams 436 and 441 are utilized, cam 441 setting the shutter to its slowest speed and bulb slot 423 latching the shutter open by engaging a pin 424 in the shutter mechanism while cam 436 allows manual setting of the diaphragm. For flash photography, the changeover member 419 is set to the flash symbol 427b when the shutter is set to its lowest speed by cam 441 while cam 435 allows the diaphragm to be manually set in accordance with flash numbers.