Patent GB-1294102-A (GB)
Title: A camera having an indicator for flash light photography
IPC: G03B7/12
Filed: 1969-10-28
Abstract: 1294102 Photographic cameras CANON K K 28 Oct 1969 [28 Oct 1968 6 Dec 1968] 52856/69 Heading G2A In a camera having an exposure metering circuit comprising a photo-sensitive power source, as shown, Fig.2, a photo-cell 2-1, and an ammeter 1 having a pointer 1-1 movable over a scale T having an EE operation range A, an over exposure range O, an under-exposure range U and a distinct "flash ready" range F, there is provided switching means 6, 11 movable between an EE operation position in which current through the ammeter is governed by the photo-cell 2-1 and is such that the pointer moves only in the ranges A, O or U, and a flash position in which the current through the ammeter is such that the pointer 1-1 can enter the range F, but only if a usable flash unit B is present. EE operation, if set, may be effected even if a flash unit is present. If the additional battery 4, provided for operating the flash unit, is dead, the pointer 1-1 will not enter the range F even if the switches 6, 11 are set for flash and a usable flash unit is present. In the embodiment of Fig.12a, the switches 6, 11 are controlled by a changeover ring 8, which, when set to "Auto" or EE operation closes switch 6, opens switch 11 and makes flash mechanism 9 (comprising various parts prefixed 9) inactive, and vice versa when set to "Flash" operation. During flash photography the diaphragm aperture is determined by setting a distance ring 9-1 and a guide number ring 9-2, which thus control the positions of pins 9-4-1 and 9-3-1, and hence, by addition, the position of the pin 9-4-4. After film wind has been completed, a switch 12 is closed, thus member 18 clears the path of release lever 20 which can thus be depressed to make a flash exposure. Initial depression of release 20 frees a connection member 19 from a shutter speed detecting member 7 which can thus rotate under spring action until portion 7-3 engages stop pin 1-2, simultaneously locked in position by clamping member 16 which has been biassed clockwise as seen by a spring 16-2, pin 16-3 preventing this movement until the member 7 is freed from the member 19. Thus a shutter speed for flash photography is obtained. Rotation of the clamping member 16 allows a lock lever 17 to rotate out of the path of the projection 20-6 of the release 20 which can thus be fully depressed to effect an exposure. As the member 7 rotates, a projection 9-5-3 follows a pin 7-5 thereof, thereby allowing iris setting ring 9-5 to rotate under spring action until cam portion 9-5-5 strikes the pin 9-4-4, before the shutter speed is set. The shutter opening movement is controlled by the member 18. For daylight operation setting the ring 8 to "Auto" brings the pin 9-4-4 out of the path of cam portion 9-5-5 by acting on the pin 9-4-1. As before the member 19 frees the shutter speed detecting member 7 and the clamping member 16. The portion 7-4 of the member 7 will engage the stop pin 1-2 to set the shutter speed depending on the brightness of the object to be photographed. The iris setting ring 9-5 rotates all the way with the member 7 so as to obtain an iris diameter dependent on the object brightness. After an exposure has been made, the lever 20 rises, the member 16 releases the stop pin 1-2 and the member 18 passes over a projection 20-5 of the lever 20 to open the switch 18 and thus disconnect photo-cell 2-1 from the ammeter 1. The pointer 1-1 enters a range 5 which denotes that the camera is not set for any type of photography. Various diagrammatic circuit arrangements are described. An additional power source may be provided for flash exposure. The photo-cell 2-1 may be replaced by a photo-conductor. The switching means may be any device such that connection of an operable flash unit with the camera will bridge a gap in the ammeter circuit. In particular a socket, if provided on the camera may constitute the switching means.