Abstract: Discharge apparatus comprises a xenon-filled glass envelope with a common cathode that divides the envelope into two separate gas-containing chambers. Respective anodes are provided in each chamber to cooperate with the common cathode. By placement of the cathode a closer distance to one of the anodes, the impedance of the discharge path between the more closely spaced electrodes is made lower than the impedance of the discharge path in the other chamber. To make the impedance even lower, the pressure of the gas between the closely spaced electrodes is made lower than the gas pressure between the other pair of electrodes. The discharge apparatus is particularly useful in quenchable electronic flash apparatus employing both a flash tube and a low-impedance quench tube.

Abstract: Electronic strobe flash apparatus includes a first energizable flashtube arranged to project light for reflection from a surface to illuminate a scene indirectly, and a second energizable flashtube arranged to illuminate the scene directly. A sequencing circuit controls the energization of both flashtubes so that the ratio of the indirect flash to the direct flash reflected from the scene is constant in instances where the reflected flash is above a minimum level. For this purpose, a light-sensitive circuit, arranged to sense light reflected from the scene, is coupled to the sequencing circuit. The sequencing circuit causes the indirect flash to be produced first. The light-sensitive circuit causes the sequencing circuit to (1) quench the first flashtube to extinguish the indirect flash, and (2) fire the second flashtube to produce the direct flash, when the light-sensitive circuit senses that a predetermined fraction of a desired total amount of light has been reflected from the scene.

Abstract: An electronic strobe flash unit in a camera is charged in response to actuation of a shutter-release member, and also in response to termination of a post-exposure film advance operation. These charging intervals are limited, respectively, by the actuation speed of the release member and by the time lapse between successive exposures. For supplementary charging of the flash unit, a potential charging delay is established, prior to exposure, when the release member is moved to a position in which the exposure operation is irreversibly initiated. This delay is potentially long enough to assure that the flash unit is charged sufficiently to produce a flash regardless of its previous condition, but is sufficiently brief to avoid disturbing the camera operator.

Abstract: A camera includes (1) a socket for detachably receiving a flashbulb, (2) a flash sensing member for detecting the presence and absence of a flashbulb in the socket, (3) a diaphragm for adjusting an exposure aperture as a function of whether the ambient light is bright or dim, and (4) a photosensor, responsive to visible light and infrared (IR), for controlling an exposure in accordance with the total visible light and IR passing along a light path to energize the photosensor during an exposure interval. An IR-attenuating filter is mounted for movement between a normal first position in alignment with the light path for effectively blocking IR from impinging upon the photosensor, and an actuated second position outside the light path to enable IR to energize the photosensor.

Abstract: A camera, operable in flash and ambient exposure modes, has adjustable lens apparatus useful for close-up and normal range photography. A photoconductively controlled electromagnet, which is energized in accordance with the intensity of ambient light, controls an apertured blade to adjust an exposure aperture. A mechanism is responsive to adjustment of the lens apparatus for a close-up photograph and overrides the electromagnet. This causes the apertured blade to be moved automatically to its minimum aperture position, independently of the exposure mode, when the camera is set for close-up photography, to enhance depth of field.

Abstract: A camera includes (1) a socket for detachably receiving a flashbulb, (2) a sensing member, coupled to the socket, for sensing a flashbulb, and (3) a photosensor, responsive to visible light and infrared (IR), for controlling an exposure in accordance with the visible light and IR passing along a light path to the photosensor during an exposure interval. A full IR-attenuating filter, responsive to the sensing member, is normally biased into alignment with the light path for effectively blocking IR from impinging upon the photosensor when an exposure is made solely in ambient light, and is positioned outside the light path when a flash exposure is made. A partial IR-attenuating filter (800 nanometers and above), coupled to the sensing member, is located in the optical path while a flashbulb is in the socket to allow the prevailing IR between 700 and 800 nanometers to influence the control of a flash exposure.

Abstract: A battery-powered DC to DC converter is operated dynamically in accordance with the condition of the battery so that an optimum compromise is made between the performance of the battery and the performance of the converter in an application such as charging an electronic strobe flash unit capacitor. A transformer has oppositely wound primary and secondary windings. A switching transistor, serially connected between the primary winding and the battery, interrupts battery current through the primary winding, which causes current to flow through the secondary winding to charge the flash unit capacitor. A voltage-sensing circuit senses the battery open-circuit voltage and the battery load voltage, which varies as a function of the open-circuit voltage and battery internal resistance.

Abstract: A camera includes a photographic film having a given film speed which decreases when the film is exposed to light which varies from a given illumination level. A camera shutter is controlled by a timing circuit adapted to produce an exposure which is adjusted to compensate for the decreased film speed.

Abstract: Electronic strobe flash apparatus has first and second flashtubes which are fired alternately and repeatedly to produce a composite, extended light flash. A start pulse triggers the first flashtube to cause a first normally charged capacitor to discharge through a primary winding of a transformer, the first flashtube, and a second normally discharged capacitor, thereby firing the first flashtube and charging the second capacitor. The transformer is adapted to produce a flashtube trigger voltage across its secondary winding when current in its primary winding is interrupted. The second capacitor is smaller than the first capacitor so that the voltage across the second capacitor increases more rapidly than the decrease in voltage across the first capacitor during its discharge.

Abstract: A battery-powered electronic strobe flash apparatus has a flashtube, which produces radiation in proportion to the energy delivered to it. A transformer has a primary winding, connectable to the battery, for storing energy in the transformer and a secondary winding, connected to the flashtube, for delivering the stored energy to the flashtube when the primary winding is disconnected from the battery. An actuatable switch has a first condition for connecting the battery to the primary winding to saturate the transformer, and a second condition for disconnecting the battery from the primary winding, thereby causing a substantially constant amount of energy to be delivered to the flashtube, whereby a substantially constant amount of flashtube radiation is produced each time the switch is actuated.

Abstract: A camera includes a battery-powered electronic strobe flash unit having a flashtube and a capacitor chargeable by the battery for supplying energy to fire the flashtube. A switch has first and second conditions for respectively preventing and causing the charging of the capacitor. A cover member is mounted for movement from (1) a viewfinder-covering position for preventing a scene to be photographed from being framed within the camera's viewfinder, into (2) a viewfinder-uncovering position for permitting the scene to be framed. A shutter release button is coupled to both the switch and the cover member for causing the switch to assume its second condition and the cover member to move into its viewfinder-uncovering position during pre-exposure movement of the release button. This causes charging of the capacitor while a scene is being framed without delaying the photographic exposure.

Abstract: An electronic flash unit has a safety circuit for removing stored electrical energy that is potentially hazardous to a flash unit user. A switch, responsive to opening of the flash unit housing, is closed to energize a quench circuit, which is parallel to a chargeable flash firing capacitor. The firing capacitor discharges through the quench circuit, thereby lowering the stored electrical energy to a level that is not hazardous to an operator.

Abstract: A quenchable electronic flash for use with a camera having an M-contact flash synchronization device, includes a flashtube for producing light, a light-responsive integrating circuit for producing a flash terminating signal when the quantity of light measured by the integrating circuit reaches a predetermined level representative of a desired film exposure, and a quench circuit responsive to the flash terminating signal for terminating the production of further light by the flashtube. A time control circuit, responsive to actuation of the flash synchronization device, energizes the integrating circuit substantially with initial opening movement of a shutter of the camera. As a result, the integrating circuit is prevented from responding to any light prior to initiation of an exposure interval and responds to a quantity of light that corresponds substantially to the light, e.g. ambient as well as flash, impinging on film in the camera during an exposure.

Abstract: A sensor in a camera detects code indicia on a film cartridge, representing information about the film in the cartridge, and an interface unit associated with the sensor transmits binary representations of the code to a microprocessor. A memory device contains a catalog of digital data representing information about a variety of films. The microprocessor selectively retrieves from memory those data corresponding to any of the information coded on the cartridge. Character generators, controlled by the microprocessor, effect display, preferably in the camera's viewfinder, of alphanumeric information representing the data selectively retrieved from memory.

Abstract: An exposure control circuit of the type adapted to produce an exposure termination signal after a time interval related to a time integral of light intensity. The control circuit includes lag compensation means responsive to the light intensity at the time the exposure termination signal is produced, or responsive to a change in light intensity from the beginning of exposure measurement to the time the exposure termination signal is produced, to adjust the time interval to compensate for lag. The control circuit further includes improved lag compensation means responsive to the time rate of change of light intensity at the time that the exposure termination signal is produced for further adjusting the time interval to thereby provide improved lag compensation.

Abstract: Electronic imaging apparatus, preferably an electronic still camera, employs an inexpensive information-recording medium such as audio-grade magnetic tape for "capturing" scene images. The camera includes a charge coupled device comprised of an array of photosensitive elements which form a charge pattern corresponding to an optical image projected onto the elements during an exposure interval. A charge transfer circuit converts the charge pattern into a high frequency pulsed electrical signal immediately following the exposure interval to remove the charge from the device in a short period of time to maintain unwanted "dark current" at a low level. Each pulse represents the image-forming light projected onto a particular photosensitive element. A high speed analog-to-digital converter converts these pulses to multi-bit digital words in real time. A digital buffer memory temporarily stores these words, then retransmits them at a rate that is compatible for recording on the audio-grade tape.

Abstract: In a self-cocking impact shutter, an opening blade is held closed prior to shutter actuation by engagement of a releasably held impact driver with a first tab on the opening blade. When the impact driver is released, it encounters a second tab on the opening blade to open the shutter and hold the opening blade in an open position by continued engagement with the second tab. A low inertia closing blade is held open by an electromagnet that attracts an armature carried by a cantilever spring. The cantilever spring is held in engagement with the closing blade by the electromagnet. The shutter is re-cocked by return of the high energy lever to its releasably held position.

Abstract: A camera having a self-cocking shutter with a shutter actuating member for initiating exposures and a film unit advancing member for advancing film units into the nip of a processing roller assembly, includes a shutter actuating member latch that is coupled to the film unit advancing member. The shutter actuating member latch serves as a double exposure prevention latch when the film unit advancing member has not advanced a previously exposed film unit.

Abstract: A mechanism for cocking the firing spring of a piezoelectric generator in a photographic camera includes a ramp surface on a body release member that is movable into engagement with the firing spring during return movement of the body release member, to move the firing spring to a latched position. A latch is provided to maintain the firing spring in its latched position during a first portion of the operation of the body release member and to release the firing spring in synchronism with actuation of a photographic shutter.