Camera and electronic flash combination

An automatic electronic flash unit for use with a camera including a first flashlight illumination control circuit, said electronic flash unit comprising:

• a second flashlight illumination control circuit;
• a terminal for receiving an output of said first flashlight illumination control circuit;
• a control circuit for terminating flashlight illumination;
• said control circuit having its input connected to the output of said second flashlight illumination control circuit and to said terminal;
• said electronic flash unit having a negligibly small value of resistance between said first flashlight illumination control circuit and said input of said control circuit as compared with a value of resistance between said second flashlight illumination control circuit and said input of said control circuit, whereby said control circuit is prevented from being operated by the output of said second flashlight illumination control circuit when said electronic flash unit is connected to said camera.

A camera unit and automatic electronic flash unit combination;

• wherein said camera unit comprises:
• an electrical shutter of the non-memory through-the-taking-lens photometry type including a first photometric circuit having a first photometric light sensitive element and including a shutter control circuit responsive to an output of said first photometric circuit for producing a first flashlight illumination control signal;
• a first terminal for transmitting said first flashlight illumination control signal to said automatic electronic flash unit;
• means in said automatic electronic flash unit for sending a first or a second operating condition signal;
• a second terminal having the capacity for receiving said first or second operating condition signal supplied by said automatic electronic flash unit, said first operating condition signal indicating a charging operation of a main capacitor for energizing a flash discharge tube of said automatic electronic flash unit and said second operating condition signal indicating a termination of a flashlight illumination control operation;
• a third terminal representing a common ground connection;
• and
• a fourth terminal for connection to an X contact;
• and
• wherein said automatic electronic flash unit is detachably coupled to the camera unit and comprises:
• a fifth terminal adapted to be connected to said first terminal for receiving said first flashlight illumination control signal from said camera, said first flashlight illumination control signal being effective to terminate a flashlight illumination of said automatic electronic flash unit;
• a sixth terminal adapted to be connected to said second terminal for transmitting said first or second operating condition signal to said camera unit;
• a seventh terminal adapted to be connected to said third terminal;
• and
• an eighth terminal adapted to be connected to said fourth terminal;
• thereby forming four pairs of terminals through which the electric circuit of said automatic electronic flash unit can be electrically connected to the electric circuit of said camera unit.

A camera unit and automatic electronic flash unit combination;

• wherein said camera unit comprises:
• an electrical shutter of the non-memory through-the-taking-lens photometry type including a first photometric circuit having a first photometric light sensitive element and including a shutter control circuit responsive to an output of said first photometric circuit for producing a first flashlight illumination control signal;
• a first terminal for transmitting said first flashlight illumination control signal to said automatic electronic flash unit;
• means in said automatic electronic flash unit for sending a first or a second operating condition signal;
• a second terminal for receiving said first or second operating condition signal supplied by said automatic electronic flash unit, said first operating condition signal indicating a charging operation of a main capacitor for energizing a flash discharge tube of said automatic electronic flash unit and said second operating condition signal indicating a termination of a flashlight illumination control operation;
• a third terminal representing a common ground connection;
• a fourth terminal for connection to an X contact;
• a logic circuit connected to said second terminal for receiving and storing said first operating condition signal supplied by said automatic electronic flash unit;
• a limiter circuit including a capacitor-resistor timer circuit which forcibly operates said shutter control circuit at a predetermined time interval after a shutter release operation;
• a photography mode switching circuit for supplying an electrical signal to said shutter control circuit which prevents said shutter control circuit from being activated by a limiter signal supplied by said limiter circuit;
• and
• a gate circuit responsive to an output of said logic circuit in response to said first operating condition signal for supplying said first flashlight illumination control signal as a shutter closing signal for said shutter control circuit to said first terminal;
• and
• wherein said automatic electronic flash unit is detachably coupled to the camera unit and comprises:
• a fifth terminal adapted to be connected to said first terminal for receiving said first flashlight illumination control signal from said camera, said first flashlight illumination control signal being effective to terminate a flashlight illumination of said automatic electronic flash unit;
• a sixth terminal adapted to be connected to said second terminal for transmitting said first or second operating condition signal to said camera unit;
• a seventh terminal adapted to be connected to said third terminal;
• and
• an eighth terminal adapted to be connected to said fourth terminal;
• and
• thereby forming four pairs of terminals through which the electric circuit of said automatic electronic flash unit can be electrically connected to the electric circuit of said camera unit.

A camera unit and automatic electronic flash unit combination according to claim 21, 5, 6, or 7 wherein said automatic electronic flash unit comprises:

• a power supply circuit;
• a flashlight illumination circuit comprising said flash discharge tube, an associated main switching element, a second display element adapted to be turned on as said main capacitor is completely charged by said power supply circuit, and an automatic flashlight illumination control circuit of the series controlled type including a commutating capacitor and an auxiliary discharge tube, said flash discharge tube being discharged to thereby produce the flashlight illumination when a first switching element is turned on;
• a flashlight illumination control circuit comprising a second photometric light sensitive element for producing a second flashlight illumination control signal in accordance with the amount of light incident upon the second photometric light sensitive element, said flashlight illumination control circuit causing said auxiliary discharge tube to discharge in response to said second flashlight illumination control signal supplied by the second photometric light sensitive element or in response to said first flashlight illumination control signal supplied by the camera unit through the first terminal to thereby interrupt the flashlight illumination of the flash discharge tube;
• a display circuit comprising a first capacitor charged through the flash discharge tube as said main switching element is turned off by means of said commutating capacitor, a second capacitor, a third display element which is connected to said first capacitor in parallel with said second capacitor and which is turned on-and-off by the discharge of said first capacitor to thereby indicate the termination of the flashlight illumination and a second switching element controlled by the current flowing through said second and third display elements, said second switching element being connected to said sixth terminal;
• and
• said first flashlight illumination control signal from the camera unit functioning, when said camera unit and automatic flash unit combination is in one of two conditions in which said changeover switch provided in the camera is closed and in which said gate circuit is operative, for supplying said first flashlight illumination control signal to said first terminal, and said second flashlight illumination control signal functioning when said camera unit and automatic flash unit combination is not in said two conditions.

A camera unit and automatic electronic flash unit combination comprising:

• a camera unit having an electrical shutter of the non-memory through-the-taking-lens photometry type and including a first photometric circuit including a first photometric light sensitive element for automatically determining an exposure period, a shutter control circuit responsive to an output of the first photometric circuit, a first terminal to which is applied a first flashlight illumination control signal from the shutter control circuit for closing said shutter, a changeover switch for providing a connection or a disconnection between the first terminal and the shutter control circuit;
• and an automatic electronic flash unit detachably coupled to the camera and including a second photometric circuit including a second photometric light sensitive element for automatically determining the exposure period, a flashlight illumination control circuit including a flash discharge tube and responsive to the first flashlight illumination control signal from the camera or an output signal of the second photometric circuit for interrupting a flashlight illumination of the flash discharge tube, and a second terminal adapted to be connected to the first terminal of the camera for transmitting the first flashlight illumination control signal to the flashlight illumination control circuit, thereby allowing the illumination control circuit to be predominantly controlled by the first flashlight illumination control signal from the camera over the output signal of the second photometric circuit of the automatic electronic flash unit depending on the operative condition of the changeover switch;
• and
• said flashlight illumination control circuit being connected to a switching circuit whose input is connected to said first terminal and to said second photometric circuit, the resistance between said shutter control circuit and said input of said switching circuit being negligibly small as compared with the resistance between said second photometric circuit and said input of said switching circuit, whereby an output of said second photometric circuit is shunted to the camera, being disabled to operate said switching circuit, when said changeover switch is closed to make said connection.