Abstract: An apparatus for reflection photometry of a single lens reflex camera includes a first shutter blind, the surface of which exhibits a reflectivity which is nearly one-half the reflectivity of a film surface. During the time a photoelectric transducer element, used for photometry, receives light reflection from the surface of the first blind, an output from a photometric circuit is doubled so as to be substantially equal to the output produced when the transducer element receives light reflection from the film surface during the running of the first blind.

Abstract: A reflex photometric assembly for a camera is integrally formed of a reflecting member for directing light reflected by a shutter blind and a film surface to a photoelectric transducer element for photometry and a shield member for preventing the light reflected by the shutter blind and the film surface from directly impinging upon the photoelectric transducer element so that both the reflecting member and the shield member can be accurately positioned in relation to the photoelectric transducer element without need for further adjustment.

Abstract: A photometric assembly of the reflective photometry type is provided in which light passing through a taking lens and reflected by a blind surface of a shutter or a film surface is directed by a reflecting member so as to be incident on a photometric, photoelectric transducer element disposed on a printed circuit board. A shield member is disposed to prevent the direct incidence of the reflected light from the blind surface or the film surface onto the transducer element.

Abstract: An apparatus is provided for use with a motor drive for cancelling the electromagnetic reaction energies developed by a pair of drive motors upon rapid starting or sudden stopping, the latter occurring upon the application of dynamic braking to said motor drive. The apparatus comprises a pair of motors each provided with rotors preferably having moments of inertia which are substantially equal. The output shafts of the motors are operatively connected so as to rotate in opposing directions.

Abstract: A camera includes a circuit which determines the level of a supply voltage and a self-timer delay circuit associated with an electrical shutter. The camera also includes an acoustic indicator which includes a pulse oscillator and a small size acoustic alarm unit and which operates to produce a sound substantially continuously to indicate the level of the supply voltage and to produce a sound intermittently in order to indicate that the self-timer is in operation.

Abstract: A release electromagnet assembly having a permanent magnet associated with a movable member and which also includes an electromagnet cooperating with the magnet to produce a magnetic attraction therebetween which is effective to constrain the movable member and which is effective to produce a force of repulsion opposing the attraction of the permanent magnet, thereby releasing the movable member for free movement. The permanent magnet has an end pole of a single polarity where it abuts against the electromagnet so that the flux from the magnet partly passes through an external magnetic path external to the yoke of the electromagnet. When energized, the electromagnet produces a flux passing through a magnetic path which is provided internally of the yoke and which opposes the flux from the permanent magnet, thus releasing the movable member from its constraint applied by the permanent magnet.

Abstract: An apparatus is provided for use with a motor drive for cancelling a reaction energy of a drive motor upon rapid starting or sudden stop. The apparatus comprises a revolving member adapted to be operatively connected with the rotor of the drive motor. The member has an inertia which is equal to that of the rotor, and is adapted to be connected with the latter in the opposite sense therefrom.

Abstract: A single lens reflex camera with electrical shutter comprises an electromagnet assembly which is energized from a power supply whenever the supply voltage is above a given level. The camera includes a movable reflecting mirror which is adapted to move upwardly in response to a shutter release operation. The camera comprises a mirror blocking mechanism which permits an upward movement of the mirror when the electromagnet assembly is energized, but which blocks the mirror in the course of its upward movement when the electromagnet assembly is not energized to provide an alarm that the supply voltage is reduced. A self-timer delay circuit is also provided to delay the energization of the electromagnet assembly.