Abstract: A photographic camera with automatic setting of diaphragm and exposure time. A light sensitive circuit generates pulses and is connected to a diaphragm counting stage for comparing signals from the light sensitive circuit with preset signals in the diaphragm counting stage and for providing a stop pulse to an electromagnetic diaphragm setting stage. A counter is connected to a pulse generator and to the diaphragm counting stage in a stop control connection. A start control provision connects the output of the diaphragm counting stage to an exposure time forming stage. The exposure time forming stage can be connected to the counter for providing automatic setting of the time determining part of the exposure time forming stage depending on the counting state of the counter. A shutter opening member can be connected to the diaphragm counting stage for receiving a control signal for the release part of the shutter opening member.

Abstract: Apparatus for stepwise transport of exposed and developed photographic films through a copying machine so as to place selected film frames, namely those film frames which are to be imaged onto photographic paper and are designated by holes or other types of indices, into register with the copying station has two photoelectronic detectors the first of which transmits signals to the forward input and the second of which transmits signals to the reverse input of a forward and reverse counter in a circuit which regulates the speed of the film transporting motor. The second detector is located downstream of the first detector and both detectors transmit signals on detection of indices denoting the film frames to be copied.

Abstract: The output of a bridge circuit which is unbalanced when the quantity of light falling on a light-sensitive element is less than or more than a predetermined light quantity is applied to a differential amplifier circuit whose output varies from a minimum amplitude to a maximum amplitude. The output of the differential amplifier is connected to a first and second threshold circuit whose threshold values are symmetrical to the output value of the differential amplifier when the bridge is in balance. The gain of the differential amplifier is adjusted so that the differential output signal has an amplitude exceeding the first threshold value and less than the second threshold value for variations of light within an allowable range. Within this range the first threshold circuit furnishes an output signal and the second threshold circuit does not.

Abstract: The camera shutter is opened. An electromagnet is energized to keep the shutter open. A first timing circuit includes a photosensitive element exposed to scene light through which a timing capacitor charges. The voltage across the timing capacitor is applied to a threshold circuit which deenergizes the electromagnet when a predetermined capacitor voltage is reached. An auxiliary timing circuit includes an auxiliary capacitor which is charged independently of scene light. An auxiliary threshold circuit produces a control signal when the auxiliary capacitor voltage reaches a predetermined voltage, corresponding to a predetermined time interval. This control signal renders conductive an electronic switch connected across the photosensitive element of the first timing circuit, thereby causing the electromagnet to become deenergized. In this way, if the first timing circuit does not cause the shutter to close within the predetermined time interval, the auxiliary timing circuit does.

Abstract: The output of a bridge circuit which is unbalanced when the quantity of light falling on a light-sensitive element is less than or more than a predetermined light quantity is applied to a differential amplifier circuit whose output varies from a minimum amplitude to a maximum amplitude. The output of the differential amplifier is connected to a first and second threshold circuit whose threshold values are symmetrical to the output value of the differential amplifier when the bridge is in balance. The gain of the differential amplifier is adjusted so that the differential output signal has an amplitude exceeding the first threshold value and less than the second threshold value for variations of light within an allowable range. Within this range the first threshold circuit furnishes an output signal and the second threshold circuit does not.

Abstract: A single operating switch replaces the main switch connecting the diaphragm control means to the battery and the release switch activating the film transport. All camera circuits are directly connected to the battery when the main operating switch is closed. An electronic switch is connected in series with the film transport motor and is closed only upon receipt of a control signal. In a first embodiment the control signal is furnished by a timing circuit after a predetermined time interval following the activation of the main operating switch. In a second embodiment the control signal is furnished by a NAND-gate which has a first input which receives a "1" signal while the diaphragm is being adjusted and a second input which receives a "1" signal while the electronic switch is open. The NAND-gate thus furnishes a "1" signal to the electronic switch causing it to be conductive at all times except when the initial adjustment of the diaphragm takes place.

Abstract: Three electric lamps with different voltage-illumination thresholds are connected to be successively turned on to show exposure times by an electronic switch, such as a transistor, connected to a voltage divider composed of a photoconductor, exposed to scene light, and a resistor.