Abstract: In an automatic focusing system for a camera having an exchangeable lens, the camera body includes a control mechanism for controlling the focus of the exchangeable lens in accordance with an output of a photoelectric focus or distance detecting element. The control mechanism is interlocked by an intermediate elongated member with a lens displacing mechanism in the exchangeable lens, with the intermediate member extending within an aperture of the lens mount. The exchangeable lens may be of the type wherein a rear lens group is moveable for focusing.

Abstract: In an exposure time control circuit for a camera adapted for manual and automatic exposure control, the resistance of a single variable resistance element is varied by a first movable member moved in accordance with at least the setting of the film sensitivity and by a second movable member moved in accordance with the manually set exposure time. Switching means connect either the first or the second independently movable member into the time control circuit. A manually operable second switching means set to a first position produces a first output signal between a photoelectric element and the variable resistance and in a second position produces a second output signal formed between a fixed resistor and the variable resistance element.The first independently movable member may also be moved in accordance with the diaphragm aperture setting.

Abstract: An exchangeable lens barrel for use in a photographic camera is provided with a light sensitive element which, when the exchangeable lens barrel has been exactly fitted to the camera, receives the light which is reflected from the light sensitive film surface after it is transmitted through the objective lens and the iris aperture of the exchangeable lens barrel. A control system for an electronic flash tube in the camera or an electronic flash device fitted to the camera comprises a lighting control circuit and includes a timing circuit which controls the lighting of the electronic flash tube. The timing circuit is connected with the light sensitive element to generate a current which is integrated by the timing circuit, and the electronic flash tube is extinguished when the integrated voltage reaches a certain predetermined level, thereby the opening of the iris aperture in the exchangeable lens barrel in transmitted to the control circuit.

Abstract: An exposure control device for a photographic camera uses a conventional exchangeable lens and achieves a highly accurate exposure control commensurate with a pre-selected shutter speed by a light measuring device measuring scene light transmitted through the objective lens, diaphragm, and exchangeable lens. The device also permits exposure control commensurate with a pre-adjusted diaphragm aperture by storing the output from the light measuring device determined with the adjusted diaphragm aperture to control the shutter speed.

Abstract: A motor-driven apparatus for use in a camera equipped with a shutter device which is normally maintained in a close position after the termination of an exposure and adapted to be shifted to an open position in response to the shutter release operation, comprises a motor for driving the film; a switch opened during the transportation of the film and closed upon the termination of the transportation of the film; an electric circuit for producing signals only when the shutter device is shifted from the open position to a closed position; and a semi-conductor control circuit connected in series with the switch between the motor and the cells, the semi-conductor control circuit being rendered conductive by signals from the electric circuit and rendered non-conductive when the switch is opened.

Abstract: A double-exposure proof camera includes a manual film advance and a solenoid which opens and closes the shutter with energization and de-energization of the solenoid. The solenoid is connected through a thyrister and a semi-conductor switch to a battery, the semi-conductor switch being closed and opened at the initiation and termination of a time interval determined by an RC network whose resistance component is controlled by a scene exposed photosensitive element. The thyrister gate is connected through a series connected pair of switches to a capacitor, one switch being closed with the depression of a shutter release member and the other switch being closed and opened respectively with a film frame being in exposure position and the film frame being advanced to discharge. The capacitor is connected to the battery through a pair of parallel switches, one of which is manually closeable and the other is closed during the advance of the film.

Abstract: An improvement is made in a camera wherein the exposure is controlled by an electronic circuit comprising a photoelectric element so situated as to receive a light reflected from the surface of photographic film in the camera.Conventional shortcomings of the above-mentioned camera that a time delay from operation of the electronic switching circuit to an actual completion of closing of the already opened shutter has been liable to cause an over-exposure and that an exposure period shorter than the delay has been impracticable can be eliminated by employing another photoelectric element which continuously receives a light from the object and influences a current to flow into a timer circuit.Moreover, by means of a change-over switch, the circuit is switched so as to be controlled substantially by the second photoelectric element in case the photographic object is so bright as to necessitate a high speed exposure faster than the time delay.

Abstract: A varifocal lens assembly of a type including at least two lens groups, a first lens group being axially movable parallel to the optical axis of the varifocal lens assembly for varying the focal length of the optical system of the varifocal lens assembly. An automatic focusing device is associated with the varifocal lens assembly to axially move the lens groups as a whole, the other or second lens group or a part of lens elements of the other or second lens group a predetermined distance to compensate for the image shift which takes place during the adjustment of the focal length effected by axially moving the first lens group.

Abstract: An exposure control device for a photographic camera uses a conventional exchangeable lens and achieves a highly accurate exposure control commensurate with a pre-selected shutter speed by a light measuring device measuring scene light transmitted through the objective lens, diaphragm, and exchangeable lens. The device also permits exposure control commensurate with a pre-adjusted diaphragm aperture by storing the output from the light measuring device determined with the adjusted diaphragm aperture to control the shutter speed.

Abstract: In an exposure control device for a photographic camera a shutter speed control signal generating circuit measures scene light transmitted through an objective lens and a diaphragm for automatically controlling the shutter speed commensurate to the measured light output. A control output signal is generated in response to a manually selectable shutter speed. A diaphragm control device controls the diaphragm aperture according to the difference in the light measuring output and shutter speed output signal. The light measuring and shutter speed output signals are selectively connectable to a shutter speed control device for exposure control. A portion of the automatic shutter speed control signal is added to the manually selected shutter speed control signal so that diaphragm aperture control is effected according to the difference between the combined signal and the automatic shutter speed control signal.

Abstract: A device for detecting focussing in an optical instrument such as a camera which has an objective lens and a plane, at which light sensitive film may be disposed, upon which a real image of an object is intended to be focussed. The device comprises a window to which the eye of the operator is held, and means for projecting light to the operator's eye which looks at the real image of the object formed by the objective lens. The light projected on the retina of the operator's eye is reflected back into the camera and is directed to focus-judging means in the nature of a light sensitive member which detects when the retina of the operator's eye is optically conjugate with an imaginary reference plane located in a position optically equal to a plane on which a real image of the object formed by the objective lens is intended to be focussed, thus also detecting when the position of the real image coincides with said reference plane so that the selected object is properly focussed.