Abstract: An automatic exposure control circuit for a camera is disclosed. The circuit is capable of automatically controlling the shutter speed when the diaphragm is manually set, and is capable of automatically controlling the diaphragm opening when the shutter speed is manually set. In both cases the same transducer is used for the manual diaphragm or shutter speed selection.

Abstract: Very precise indications of the Apex indication values in a camera are displayed through the viewfinder. The nominal value is displayed numerically and further indications are provided to display fractional parts of one step of a nominal Apex indication value.

Abstract: An automatic exposure control device is disclosed which is capable of aperture dominant and shutter speed dominant exposure control operation as well as manual exposure control operation. A logarithmic compression circuit including transducers develops voltages directly dependent upon the APEX indicating quantities Bv, Sv, Tv and Av. For automatic operation one of the voltages dependent upon Tv or Av is set into the circuit by manual control, and the other is calculated by the APEX indication formula Bv + Sv = Tv + Av, and applied as an output to the shutter control or aperture control mechanism. An indicator means is connected in the circuit to provide Tv or Av indications depending on the exposure control mode selected for the camera.

Abstract: A shutter speed setting dial is rotationally coupled to a spring biased shutter speed display dial by a string and drum arrangement. The peripheral edge of the display dial, bearing shutter speed markings, extends into one side of a viewfinder frame adjacent a column of LEDs associated with a fixed point exposure meter display. Tabs projecting from a viewfinder frame border mask opposite the center LED bracket the set shutter speed marking, thereby enabling the user to quickly observe both the shutter speed and energized LED with a single glance.

Abstract: An automatic exposure control device for a single lens reflex camera characterized in that a stop determining member which stops down diaphragm blades by rotation thereof at a predetermined speed is released by a shutter release plate. A time constant circuit is started to operate simultaneously with the start of rotation of said stop determining member, and the rotation of said stop determining member is stopped by an electromagnetic mechanism when a time has lapsed. The length of said time linearly corresponds to the stop size determined by APEX operation based on the output voltage of said time constant circuit as an operation factor.

Abstract: An automatic iris adjustment control for cameras which, using the APEX operational equations, compares the brightness value Bv and film sensitivity value Sv with the iris size indication value Av and shutter speed value Tv. The iris size indicating value Av is derived from the sum of pulses created by a pulse generator which operates in conjunction with the moving adjustment of the iris size. When the values are compared and found equal, an electro-magnet is de-energized stopping the movement of the adjustable iris at the correct iris setting.

Abstract: A shutter speed digital display device for cameras equipped with both automatic and manual shutter speed controls is disclosed. A shutter speed display control circuit generates a first digital signal in accordance with the adjustment of the camera's shutter speed by an automatic shutter speed control circuit. The first digital signal is decoded and used to control a light-transmitting liquid crystal device display. In addition, when the camera is in a manual mode of operation, the first digital signal is compared with a second digital signal related to manually adjusted shutter speed. If the comparisons are equal, a coincidence indicator is energized.

Abstract: An exposure display device for a single lens reflex camera including light display elements for displaying either shutter speed or diaphragm value is disclosed. Nominal values representing either shutter speed or diaphragm value are marked on a glass plate disposed in the vicinity of the focusing plate of the camera's viewfinder. A first display section, comprising a first set of light display elements aligned with (and, if desired, located inbetween) the nominal values, creates a first exposure component (e.g. diaphragm value or shutter speed) display whose value is related to predetermined exposure conditions, such as object brightness, film sensitivity and the other exposure component (e.g. shutter speed or diaphragm value). A second display section, comprising a second set of light display elements, also aligned with the nominal values, creates a second display of the exposure component chosen to be displayed.

Abstract: A mechanical arrangement is disclosed for blocking the electric shutter operation of a camera when the rear shutter holding electromagnet is not energized sufficiently to hold the rear shutter. A pair of gears for the front and rear shutters, respectively, are mechanically linked to the shutters to prevent their running when the gears are held stationary. A release controlled lever holds the front shutter gear stationary, and the stationary position of the front shutter gear holds the rear shutter gear stationary. When the release button is depressed the front gear is released from the lever and rotates as the front shutter runs to an unblocking position. Rotation of the front gear frees the rear gear, but the rear shutter is held by the electromagnet until the exposure time is completed. Thereafter the electromagnet is deenergized causing the rear shutter to run to its blocking position and the rear shutter gear to rotate. If the electromagnet is not sufficiently strong, e.g.

Abstract: A mirror operating arrangement for a single lens reflex camera in which during mirror operation the mirror rotation shaft moves from a viewing position to a shutter operating position is disclosed. In an individual mirror-up operation, the mirror is swung up without causing the mirror rotation shaft to be moved to the shutter operating position. Upon photographing operation, after the individual mirror-up operation, the mirror rotation shaft is moved to the shutter operating position. The shock of the mirror operating arrangement is decreased by the mirror being previously swung up in the individual mirror-up operation.

Abstract: A method and apparatus for automatic iris control of cameras having an exposure value indicator located within the camera's viewfinder. The indicator emits light such that a photosensor when moving over the indicator face, senses the light and through associated circuitry and mechanisms stops the movement of an adjusting iris.

Abstract: An exchange lens assembly integrally supports a rotatable data plate illuminated by exterior light incident upon the exchange lens bodytube through a condenser lens independent of the object focussing optical system. The iris value setting ring controlling light transmission through the object focussing optical systemm also controls light transmission through the data plate and its separate focussing optical lens for simultaneous photographing on the film of the field image and a selected data character.

Abstract: A single lens reflex camera of the TTL light measuring type and mounting interchangeable objective lenses of the fully open and stopped down aperture light measuring type includes a two coil differential meter. One of the meter coils is connected through a photocell to a battery and the other coil is connected between the battery grounded first terminal and the arm of a double throw switch. An adjustable first resistor is connected between the switch first contact which is grounded through a normally open second switch and an objective aperture varied second resistor is connected between the battery ungrounded terminal and the first switch second contact. The open aperture light measuring objective lens is provided with an actuating element which functions upon mounting of the lens to close the second switch to short circuit the second coil when the first switch first contact is closed, thereby disabling the light measuring circuit and providing an indication thereof.

Abstract: A rotatable member overlying a relatively fixed member has a quadrilateral window corresponding to a similar quadrilateral window within the fixed member through which passes the pivot axis of the rotating member. The rotating member controls movement of a pair of shield blades movable towards and away from each other from opposite sides of the window within the fixed member such that light shielding of the optical path through the fixed member window is effected partially by overlapping of the window frame portion of the rotating member relative to the window frame portion of the fixed member and the remaining portion of the fixed window is covered by the shield blades.

Abstract: A single lens reflex camera includes a separable view finder provided with a casing housing a pentaprism and electrical components. A set of laterally spaced contact pins depend from a shoulder in the casing forward of the pentaprism lower front surface and are connected to casing housed electrical components. The camera body also houses electrical components which are connected to resilient contact fingers mounted on the forward part of the camera body and underlying and releasably engaged by the contact pins. A slideable cover strip is spring urged to a position overlying the contact fingers and is retracted by the contact pins with the sliding coupling of the view finder to the camera body.

Abstract: A control assembly and method are disclosed for providing manual stop-down mirror-up operations in a single lens reflex camera having a camera ready condition wherein an automatic diaphragm arrangement normally biases a diaphragm operating member to a full open position and a quick-return mirror arrangement normally biases a mirror to a viewing position. The control includes a button externally mounted on the camera for manual rotational movement between first and second button positions and for manual depressing operation in each of the button positions. In the first button position, depression of the button biases the diaphragm operating lever to a stop-down position with the mirror in the viewing position and release of the button returns the diaphragm lever to the normal full open position. In the second button position, depression of the button again provides the stop-down operation and also biases the mirror to a mirror-up shutter operating position.

Abstract: In one arrangement, the exposure multiplication indicating means includes an exposure multiplication selector dial having a small window cut therein and numerals marked thereon representing exposure multiplication, a film sensitivity dial, and an indicium. Numerals marked on said film sensitivity dial for representing the film sensitivity are observed, one by one, through said small window cut in the exposure multiplication selector dial, and the exposure multiplication is indicated by the numeral which is marked on the exposure multiplication selector dial in alignment with said indicium. In another arrangement, a main switch energizes the automatic exposure setting circuit and also energizes an element indicating the exposure multiplication setting. A source voltage confirming circuit enables the exposure multiplication indicating means to operate only when the source voltage is of a predetermined value.

Abstract: A single lens reflex camera of the interchangeable view finder type includes a pentaprism view finder having a casing provided with opposite followers slideably engaging grooves in parallel tracks on the camera body top wall. A lock element is mounted on a swingable arm carried by the view finder casing and is spring urged into locking engagement with a recess in one of the tracks. The view finder occular is provided with a coaxial collar rotatably supporting an unlock ring having a pin projecting through a slot into the casing and connected by a lost motion coupling to one end of a link which is connected to the swingable arm so rotation of the ring disengages the lock element from the lock recess.