Abstract: The present invention relates to a light measuring circuit consisting of an operational amplifier, a feed back path connected with said operational amplifier, a photo voltaic cell and a switching circuit for bringing the input terminals of said operational amplifier to the same potential at the time light measurement is commenced. By means of this switching circuit connected to the light measuring circuit the delayed response of the light measuring circuit due to the stray capacitence existing between the input terminal of the operational amplifier and ground is remarkably improved.

Abstract: The present invention relates to a control system consisting of a semi-conductor integrated circuit for a camera, particularly a control system from providing secure operation as well as a reduction of complexity. The system provides for separation of actuating signals from the low level signals for the integrated circuit so as to prevent added noise of the actuating signals from mixing with the low level signal.

Abstract: A camera system is composed of a flash and a camera in which the diaphragm and shutter time control as well as the indicating mechanism are automatically switched into a flash mode in response to the charge accumulation completion signal from the electronic flash discharge device.

Abstract: The present invention relates to an exposure meter circuit of a camera with a matching network for a flash device with which camera auxiliary light photography can be carried out the flash device presents a detecting output terminal of a detecting network for detecting the level of the stored energy of an energy storing means provided in the flash circuit of the flash device, a voltage supply terminal for supplying the operation voltage to the detecting network and a synchronizing terminal for triggering the flash device. With this camera, daylight photographing can also be carried out without a flash device. The exposure meter circuit is characterized in that in the exposure meter circuit a current source is included for the exposure meter. A first switching means is connected with one electrode of the current source. Grounding of the current source occurs in functional connection with the switching of the flashlight photographing over to the daylight photographing.

Abstract: A temperature compensating device for devices comprising semiconductors. The temperature compensating device comprises a temperature compensating circuit, such as a circuit including a diode, and a current control circuit which adjusts the quantity of the electric current flowing through the temperature compensating circuit. The temperature characteristic of the temperature compensating circuit is mutually compensatory with that of the output of the device comprising semiconductors. When the temperature characteristic of the output of said temperature compensating circuit differs from that of the output of such semiconductor device, the current control circuit causes a current which corresponds to the difference between the temperature coefficient of the compensating circuit and that of the semiconductor device to flow through the temperature compensating circuit, so that satisfactory temperature compensation can be accomplished.

Abstract: The time period necessary to charge a current-to-light convertible energy storing capacitor to a certain voltage is reduced as compared with prior art devices. The energy storing capacitor is connected across a flash tube and switching element series-connected with each other. The switching element is provided with a control circuit, responsive to the voltage of the storage capacitor decreasing to a level at which the flash tube is stopped from producing flash light, for producing a terminating signal by which the switching element is brought into the open or non conducting state. With this arrangement, it is made possible to prevent complete discharge of the electric charge stored in the storage capacitor from occurring, thereby providing the advantage of saving a good fraction of the charging time period which would be otherwise necessary when the storage capacitor is completely discharged to zero voltage.

Abstract: An object image is formed on a screen by an objective lens. The light beam from the object image formed on the screen is guided in a direction to an eye piece by a pentagonal roof prism. Only one light measuring means is provided facing an upper part of the exit face of the pentagonal roof prism. Therefore, the light beam from the screen passing through the upper part of the pentagonal roof prism impinges into the light measuring means. Also the light beam from the screen passing through both left and right end parts of the exit face of the pentagonal roof prism is directed onto the light-measuring means through a reflective plane. A shutter means is provided at least for one of the luminous flux from the upper part of the pentagonal roof prism and the luminous flux from the both left and right end parts. The light measurement distribution in an object scene may be varied by the shutter means.

Abstract: The present invention relates to an exposure control apparatus for a camera which is so designed that the output terminal of the light measuring circuit of the brightness of the object to be photographed having a photo electric transducing means is connected to one input terminal of an operation amplifier. The output of the photographing information setting circuit, having a variable resistance means for setting other photographing informations than the information of the brightness of the object to be photographed, is connected to the other input terminal of the above mentioned operation amplifier. This is done in such a manner that proper exposure conditions can be obtained by means of the output of the exposure control circuit connected to the output of the above mentioned operation amplifier. Each input signal to the operational amplifier is adjusted by a bias signal which is controlled in accordance with ambient temperature conditions.