Abstract: A flash photography system for a photographic camera and a flash device adapted to be connected thereto with the camera providing an aperture value output for flash light photography and a flash light stop signal obtained from an integrated output of the light reflected from a photographic object to terminate flash light emission when the integrated value reaches a predetermined value. The flash device calculates a maximum photographing distance covered by the flash light for effecting a correct exposure of the photographic object from the maximum flash light value and the aperture value from the camera. The maximum photographing distance is displayed by a suitable display visible to the camera operator.

Abstract: A flash photography system using a first aperture value output calculated from a desired diaphragm aperture value for flash light photographing with data obtained from ambient light, film sensitivity and the exposure data, a second aperture value output independent of the light value of the ambient light, data selecting circuitry for outputting any one of the first aperture value output and the second aperture value output, an aperture controller for controlling the actual diaphragm aperture size from the output of the data selecting circuitry, and means for producing a stopping signal to stop the emission of the flash light when the flash light emission reaches a predetermined value.

Abstract: In a flash photography system including an electronic flash device adapted to be combined with a camera which is adapted to transmit first and second signals to an electronic flash device and to receive third and fourth signals therefrom, and wherein the third signal informs the camera of the completed preparation for flash light emission; the first signal directs the electronic flash device to initiate flash light emission; the fourth signal directs the camera to initiate light measurement upon flash light emission; and the second signal directs the electronic flash device to terminate flash light emission in accordance with the light measurement.

Abstract: An automatic exposure control camera is of a type capable of controlling both the camera exposure and the flash light amount to be emitted by an electronic flash device. The automatic exposure control camera includes an average light measuring device for measuring an amount of the entire light impinging on an image forming plane and for producing an average signal representing the average light amount, and a spot light measuring device for measuring an amount of light impinging on a spot of the image forming plane and for producing a spot signal representing the light amount at the spot.

Abstract: A flash photography system for a camera which is adapted to be used with an electronic flash device which supplies a control signal when the device is a ready condition. The camera includes a diaphragm control circuit which automatically control the diaphragm aperture in accordance with a measurement of the light from the scene to be photographed. The diaphragm control circuit includes a circuit for producing a first program signal for controlling the diaphragm aperture and camera exposure time in a first programmed relationship with the light measurement for daylight or natural light photography, and a circuit for produces a second program signal for controlling the diaphragm aperture in a second programmed relationship with the light measurement for flash photography. The second program signal is adapted to provide a proper exposure for the ambient light condition as well as the flash light illumination.

Abstract: In a flash photography system wherein an electronic flash is fired to illuminate an object to be photographed, a light measuring circuit measures the light reflected from the object and generates a stop signal when the integration of the measured light attains a given level, and the flash firing is interrupted in response to the stop signal, an indication is made when the stop signal is generated within a predetermined period from the generation of a synchro signal for firing the flash tube in conjunction with shutter opening, the period is longer than the period required for the flash tube to fully emit its light, i.e. consuming fully the charge stored in the main capacitor. The period may be approximately equal to or a little longer than a maximum flash synchronizable shutter speed.

Abstract: A dedicated electronic flash device capable of being combined with a camera and receiving a flash device identifying signal at a common terminal for establishing automatic aperture size control in a flash light exposure mode, and establishing manual aperture size control in the absence of the identifying signal. A flash light emission terminating signal, having a level greater than the identifying signal, is transmitted from the camera to the dedicated electronic flash device through the common terminal. The camera is capable of changing the automatic exposure time control and the aperture size control modes into respective flash light exposure modes in response to a charge completion signal transmitted from the electronic flash device through another terminal.

Abstract: A photographic system for use in flash photography with a camera is disclosed. The system is constructed to emit a preliminary flash light of infrared light component in advance of a main flash light emission of visible light component for flash photography in order that the preliminary flash light emission does not stimulate a human eye. The preliminary flash light is used for controlling an exposure of the camera such as an aperture of diaphragm.

Abstract: A flash photography system includes an electronic flash device capable of light measurement for automatic flash light control and a camera capable of automatic shutter speed control at a daylight photography mode and at a flash photography mode. The flash device generates a flash readiness signal and a flash light control termination signal at a common terminal for the transmission of these signals to the camera through a corresponding common terminal, wherein these signals cause the camera to effect the automatic shutter speed control at the flash photography mode. The camera generates an interrupting signal at the corresponding terminal in response to a camera release operation and the electronic flash device interrupts the generation of the flash light control termination signal in response to the interrupting signal. In indicator which makes an indication in response to the flash readiness signal and the flash light control termination signal respectively is also provided in the camera.

Abstract: A controlling device that determines the diaphragm aperture of the camera in accordance with an output of a light measuring circuit, which detects a light from an object to be photographed being illuminated by a light which includes an alternatingly changing component and has its intensity maintained constant in effect for a given time period. The device is equipped with a smoothing circuit for smoothing the ripple component in the photoelectric output. The smoothing circuit is set to have a charge time constant smaller than the discharge time constant and generates an output equivalent to the peak value of the ripple component. The light that illuminates the photographic object can be generated from the electronic flash and the photoelectric detector may be arranged within the body of a camera to receive the light from the photographic object that passes through the diaphragm aperture of the camera.

Abstract: A control circuit controls the amount of light emitted from an electronic flash tube in accordance with the voltage of a main capacitor, which energizes the flash tube, and a set guide number so that the amount of light may be constant irrespective of changes in the voltage of the main capacitor due to consumption of a power source battery from which electric energy is supplied to the main capacitor. The control circuit may include a storing or memorizing capacitor for storing a signal corresponding to the voltage of the main capacitor and further include a transistor which generates a current commensurate with the stored signal, the current being integrated to actuate a flash emission stopping circuit when the integration reaches a given level.

Abstract: Camera exposure control circuitry capable of functioning with a dedicated flash device for producing a preliminary flash light of a relatively long controllable duration at a substantially constant intensity prior to the production of primary flash light automatically changes the diaphragm aperture from an initial aperture setting to another aperture setting during preliminary flash light emission. The light received through the diaphragm aperture set during the preliminary flash light emission provides a first signal output to provide an appropriate aperture size for flash photography in response to the measured light conditions. The duration of the preliminary flash light emission is terminated by a second signal from the camera exposure control circuitry when the diaphragm aperture is determined.

Abstract: A semiconductor switching element is connected in series with a flash tube to stop emission of flash light therefrom during operation of the flash tube. A first and a second integrating circuit are parallelly arranged to be connected either alternatively, or both together, with the switching element. The first integrating circuit integrates photo-current generated by a photocell receiving light from an object illuminated by the flash light, and the second integrating circuit integrates current that is manually adjustable. When both integrating circuits are connected with the switching element, the switching element is turned off by that integrating circuit which first reaches a predetermined trigger level.

Abstract: In a system where a single power source battery is commonly used for the oscillation circuit of an electronic flash device and for another circuit, such as a control circuit for energizing a light source for a data recording for a given period of time, the operation of the oscillation circuit is interrupted by a semiconductor switching device in response to a firing of the flash tube of the flash device. The oscillation circuit interruption continues for a predetermined period during which the aforesaid another circuit is operated from the battery. To this end, the semiconductor switch may be controlled by a delay circuit.

Abstract: In an electronic flash device, wherein electrical energy stored by a main capacitor and an electronic flash tube is fired by the stored energy, a relaxation oscillator is adapted to oscillate when the main capacitor is charged to a given voltage level, which is a condition for completion of preparation for flash tube operation. The relaxation oscillator includes a capacitor, a glow discharge tube, and a resistor and the oscillation thereof causes intermittent glow discharge through the glow discharge tube for indicating the completion of preparation for flash tube operation. The electronic flash tube is triggered to emit a light flash by the stored energy of the relaxation oscillator capacitor. Excitation of the flash device, even with a power supply switch open, is prevented by isolating the main capacitor from the trigger capacitor and also from the glow discharge tube to also prevent an indication of flash preparation.