Automatic flash photography switchover device

Claim 2

An automatic flash photography switchover device for use in a camera comprising, an aperture control member for obtaining an aperture size corresponding to a photographic distance and a guide number, and means for disabling said aperture control member comprising a first movable member operative on said aperture control member when a flash circuitry in the camera is not in readiness for operation to disable same and a second movable member operative on the aperture control member only when the brightness of an object is more than a previously determined level during detection of the brightness of an object being photographed to disable same, whereby an aperture control corresponding to the set photographic distance and guide number can be obtained only when the flash circuitry is in readiness for operation and the brightness of an object is lower than the predetermined level.

Claim 3

An automatic flash photography switchover device according to claim 1, in which at least one of said first and second members associated with said aperture control member comprises means acting on said aperture control member to displace same such that an aperture set value of said aperture control member may be fixed at a maximum irrespective of the photographic distance and guide number set.

Claim 4

An automatic flash photography switchover device according to claim 1, in which at lease one of said first and second members associated with said aperture control member comprises means acting on said aperture control member when the aperture set value of said aperture control member is fixed at a maximum value, means determining the exposure aperture in a photographic exposure including an electromagnet and a delay circuit effective to interrupt current to said electromagnet in accordance with the relation of an exposure time previously programmed, and means determining the exposure aperture when both said first and second members are ineffective to act on said aperture control member for determining the action of said aperture control member comprising means restraining the opening of a sector and determining the exposure time by interruption of said current to said electromagnet due to a drop of voltage applied to said electromagnet upon firing of a flash bulb.

Claim 5

An automatic flash photography switchover device according to claim 1, including a sector-closing member, and in which said second member acting on said aperture control member in response to brightness of an object, where the brightness of an object is less than previously determined, is retained in its position not acting on a charged aperture control member by said sector-closing member and a shutter ring restraining arm during opening operation and when the brightness of an object is more than previously determined, said second member being displaced to a position to act on the aperture control member by an initial small movement of the sector-closing member and thereafter to a position not restrained by the shutter ring during subsequent opening operation.