Flash photographing system

• US 4,573,786 A
• Filed: 05/25/1984
• Issued: 03/04/1986
• Est. Priority Date: 05/27/1983
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha
• Original Assignee: Minolta Camera Kabushiki Kaisha
• Inventors: Nakai, Masaaki, Taniguchi, Nobuyuki, Tsuji, Kenji, Omaki, Takanobu, Hosomizu, Hiroshi
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US06/614,031
• Time in Patent Office: 648 Days
• Field of Search: 354/415, 354/416, 354/418, 354/145.1, 354/132, 354/286
• US Class Current: 396/159
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/0557 Multiple units, e.g. slave-unit
• CPC Class Codes: G03B 2215/056 Connection with camera, e.g. adapter
• CPC Class Codes: G03B 7/16 in accordance with both the intensity of the flash source and the distance of the flash source from the object, e.g. in accordance with the "guide number" of the flash bulb and the focusing of the camera

Abstract

A flash photographing system includes a camera body, a flash controller connected to the camera body and three flash devices: the first flash device is directly mounted on the camera body; the second flash device is mounted on the flash controller; and the third flash device is connected through a suitable cord to the flash controller. A microcomputer is provided in the camera body and also in each of the flash devices so as to control the three flash devices in various different modes of operations, such as simultaneous flash mode, sequence flash mode, and yet providing an appropriate amount of light for the proper exposure.

Claims

1. In a flash photographing system including a combination of a camera, a controlling device connectable to the camera, a first electronic flash device connectable to the controlling device and a second electronic flash device directly connectable to the camera, the combination comprising:

first to third terminals included in the first electronic flash device;

first to third terminals included in the second electronic flash device;

fourth to sixth terminals included in the controlling device connectable with said first to third terminals of the first electronic flash device, respectively;

seventh to ninth terminals included in the controlling device;

tenth to twelfth terminals included in the camera connectable with said seventh to ninth terminals of the controlling device, respectively;

thirteenth to fifteenth terminals included in the camera connected to said tenth to twelfth terminals, respectively, and connectable with said first to third terminals of the second electronic flash device, respectively;

wherein, each of the first and second electronic flash devices includes means for initiating flash light emission in response to a flash initiating signal received through said first terminal, means for providing a light measurement controlling signal through said second terminal, means for serially forwarding data descriptive of electronic flash device conditions through said second terminal in response to a train of clock pulses received from said third terminal, means for serially receiving information from said second terminal in response to the train of clock pulses for operation of the electronic flash device, means for governing the mutual communication through said second terminal with a device connected thereto in response to a communication controlling signal received from said third terminal, and means for terminating flash light emission in response to a flash terminating signal received through said third terminal;

wherein the controlling device includes first means for transmitting the flash initiating signal from said seventh terminal to said fourth terminal, second means for transmitting the light measurement controlling signal from said fifth terminal to said eighth terminal, third means for transmitting information from said eighth terminal to said fifth terminal, fourth means for transmitting the clock pulses, the communication controlling signal and the flash terminating signal from said ninth terminal to said sixth terminal, means for serially receiving the data of the first electronic flash device through said fifth terminal and the data of the second electronic flash device through said eighth terminal in response to the clock pulses received through said ninth terminal, means for determining the manner of flash light emission of the first and second electronic flash devices in accordance with said data receiving means, means for serially forwarding information representative of the manner of flash light emission to the first electronic flash device through said fifth terminal and to the second electronic flash device through said eighth terminal, respectively, in response to the clock pulses received through said ninth terminal, means for appreciating the total conditions of the first and second electronic flash devices in accordance with said data receiving means, means for serially informing the camera of the appreciated total conditions of the first and second electronic flash devices through said eighth terminal in response to the clock pulses received through said ninth terminal, and means for governing the mutual communication with the first electronic flash device through said fifth terminal and with the camera through said eighth terminal in response to the communication controlling signal received from said ninth terminal; and

wherein the camera includes first means connected to said tenth terminal for producing the flash initiating signal, second means connected to said twelfth terminal for producing the train of clock pulses, third means connected to said twelfth terminal for producing the communication controlling signal, means for measuring light in response to the light measurement controlling signal received through said eleventh terminal to produce the flash terminating signal through said twelfth terminal, fourth means connected to said eleventh terminal for producing information to be transmitted to the first and second electronic flash devices, and means connected to said eleventh terminal for receiving the appreciated total conditions of the first and second electronic flash devices.

2. The combination as claimed in claim 1, wherein said initiating means in each of the first and second electronic flash devices includes first means for directing a flash light emission in instant response to the flash initiating signal, second means for directing a flash light emission in response to the flash initiating signal with a predetermined delay, and means for selecting between said first and second directing means in accordance with the information representative of the manner of flash light emission received by said receiving means.

3. The combination as claimed in claim 2, wherein said determining means in the controlling device includes means for transmitting by way of said forwarding means information to select a predetermined one of said first and second directing means in the first electronic flash device through said fifth terminal and information to select the other of said first and second directing means in the second electronic flash device through said eighth terminal, when said data receiving means in the controlling device is informed that both the first and second electronic flash devices are operative.

4. The combination as claimed in claim 3, further comprising a third electronic flash device connectable to the controlling device, wherein the controlling device further includes third means for directing the third flash device to emit flash light in response to the flash initiating signal with a predetermined delay greater than that of said second directing means.

5. The combination as claimed in claim 3, wherein the controlling device further includes means for manually setting a simultaneous occurrence of multiple flash light emissions, and said transmitting means is adapted to transmit information to select the first directing means in both the first and second electronic flash devices with said manually setting means operated.

6. The combination as claimed in claim 2, wherein said providing means in each of the first and second electronic flash device includes means for sequentially sending two light measurement controlling signals in synchronism with the operation of said first and second directing means, respectively.

7. The combination as claimed in claim 6, wherein said measuring means in the camera includes means for integrating measured light, first means for starting the integration in response to the first one of the two light measurement controlling signals and for producing a first flash terminating signal when the integrated light reaches a predetermined portion of a required amount, and second means for restarting the integration in response to the second one of the two light measurement controlling signals and for producing a second flash terminating signal when the integrated light amount reaches the remainder of the required amount.

8. The combination as claimed in claim 7, wherein said measuring means further includes third means for starting the integration in response to the first one of the two light measurement controlling signals to continue the integration regardless of the second one of the light measurement controlling signals with the first flash terminating signal not produced and for producing the second flash terminating signal when the integrated light amount reaches the full required amount.

9. The combination as claimed in claim 2, wherein the camera further includes means, responsive to said receiving means, for setting a first flash synchronized exposure time when said first directing means in the electronic flash device is only operative and for setting a second flash synchronized exposure time greater than the first one when said first and second directing means are both operative.

10. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for checking the level of the stored electric power;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal coming from the operative device for operation of said initiating means;

a second terminal connectable with the operative device for mutual communication therewith;

means for serially forwarding data descriptive of electronic flash device conditions to be transmitted to the operative device through said second terminal, said checking means being connected to said forwarding means for subjecting its checking result to the serial forwarding means as first data;

means for serially receiving information from the operative device through said second terminal for operation of the electronic flash device;

a third terminal connectable with the operative device for receiving a train of clock pulses from the operative device for operation of said forwarding means and said receiving means; and

means for governing the mutual communication through said second terminal in response to a communication controlling signal coming from the operative device through said third terminal.

11. The electronic flash device as claimed in claim 10 further comprising means, responsive to the flash initiating signal, for providing a light measurement controlling signal to be transmitted to the operative device through said second terminal, and means for terminating flash light emission by said emitting means in response to a flash terminating signal from the operative device through said third terminal.

12. The electronic flash device as claimed in claim 11, further comprising means, connected to said forwarding means, for generating second data indicating that the electronic flash device is operative in the system, and means, connected to said forwarding means, for generating third data when the flash terminating signal appears at said third terminal within a predetermined time period, wherein said forwarding means includes means for serially sending said first data, said second data and said third data to the operative device through said second terminal in response to said clock pulses received at said third terminal.

13. The electronic flash device as claimed in claim 11, further comprising means for latching data appearing at said second terminal at a predetermined time, and means, responsive to the latched data, for preventing said initiating means from operating in response to the flash initiating signal.

14. The electronic flash device as claimed in claim 11, further comprising means for forming a higher output impedance at said second terminal than the input impedance thereof.

15. The electronic flash device, as claimed in claim 13, further comprising means for forming a higher output impedance at said second terminal than the input impedance thereof.

16. The electronic flash device as claimed in claim 11, wherein the operative device is a camera capable of controlling exposure selectively in accordance with an automatic and manual modes and informing the electronic flash device of the selected exposure control mode through said second terminal, and the electronic flash device further comprises means for manually disabling the response of said terminating means to the flash terminating signal, and means for reviving the response of said terminating means to the flash terminating signal when said receiving means receives information representative selection of the automatic exposure control mode even if said disabling means is manually operated.

17. The electronic flash device as claimed in claim 11, wherein said initiating means includes first means for directing said emitting means to emit flash light in instant response to the flash initiating signal, second means for directing said emitting means to emit flash light in response to the flash initiating signal with a predetermined delay, and means for selecting between said first and second directing means in accordance with the information received by said receiving means.

18. The electronic flash device as claimed in claim 17, wherein said terminating means includes means for accepting said flash terminating signal at a time accommodating to the selected one of the first and second directing means in accordance with the information received by said receiving means.

19. The electronic flash device as claimed in claim 18, further comprising means, connected to said forwarding means, for generating data when the flash terminating signal appears at said third terminal within a predetermined time period, and means, responsive to said receiving means, for restraining said generating means from generating the data when said first directing means is selected and it is informed that another electronic flash device is operative in the system to emit another flash of light with a delay.

20. The electronic flash device as claimed in claim 17, further comprising means for calculating indicative information relating to an object distance in flash photography in accordance with information received by said receiving means, means, responsive to said calculating means, for indicating the indicative information, and means, responsive to said receiving means, for prohibiting said indicating means from indicating the indicative information when said first directing means is selected and it is informed that another electronic flash device is operative in the system to emit another flash of light with a delay.

21. The electronic flash device as claimed in claim 20, further comprising means for preparing fixed information to be substitutionally utilized by said calculating means in case said receiving means fails to receive information through said second terminal.

22. The electronic flash device as claimed in claim 17, wherein said providing means includes means for sequentially sending two light measurement controlling signals in synchronism with the operations of said first and second directing means, respectively.

23. The electronic flash device as claimed in claim 11, wherein said emitting means includes first and second electronic flash tubes, and said initiating means includes first means for directing said first electronic flash tube to emit flash light in instant response to the flash initiating signal and second means for directing said second electronic flash tube to emit flash light in response to the flash initiating signal with a predetermined delay.

24. The electronic flash device as claimed in claim 23, further comprising means for adjusting a light emitting direction of said first electronic flash tube, and means, responsive to said adjusting means, for inhibiting said second directing means from directing said second electronic flash tube to emit flash light when the light emitting direction of said first electronic flash tube is the same as that of said second electronic flash tube.

25. The electronic flash device as claimed in claim 24, further comprising means for calculating indicative information relating to an object distance in flash photography in accordance with information received by said receiving means, said calculating means being adapted to calculate the indicative information with respect to said first electronic flash tube with said inhibiting means operative and with respect to said second electronic flash tube with said inhibiting means inoperative, and means, responsive to said calculating means, for indicating the indicative information.

26. The electronic flash device as claimed in claim 11, further comprising means, responsive to the clock pulses, for intermittently serially forwarding the data at a predetermined sequence in the operation of said forwarding means, wherein said receiving means includes means for receiving information coming from the operative device to said second terminal during an intermission in the operation of said forwarding means.

27. The electronic flash device as claimed in claim 26, further comprising means for making said forwarding means cease to forward the data after the intermission in accordance with the information received by said receiving means.

28. The electronic flash device as claimed in claim 26, wherein said forwarding means includes means for outputting, directly before the intermission, data representing that the electronic flash device is a dedicated one in the flash exposure system, the data being formed as a low level signal preventing any undesirable influence on information to be received by said receiving means in the succeeding intermission.

29. The electronic flash device as claimed in claim 11, wherein the operative device is a controlling device connectable to a camera, and the electronic flash device is selectively connectable to one of the controlling device and the camera.

30. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for checking the level of the stored electric power to generate first data;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device;

means, for generating second data indicating that the electronic flash device is operative in the system;

means for generating third data when an expected illumination by the flash light is attained;

means for serially forwarding said first data, said second data and said third data to the operative device through said second terminal; and

a third terminal connectable with the operative device for receiving a train of clock pulses from the operative device for operation of said forwarding means.

31. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for checking the level of the stored electric power to generate first data;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device;

means for forwarding said first data to the operative device through said second terminal;

means for latching data appearing at said second terminal at a predetermined time; and

means, responsive to the latched data, for preventing said initiating means from operating in response to the flash initiating signal.

32. The electronic flash device as claimed in claim 31 further comprising means for forming a higher output impedance at said second terminal than the input impedance thereof.

33. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for checking the level of the stored electric power to generate first data;

means for forwarding said first data to the operative device;

means for initiating flash light emission by said emitting means;

means for receiving a flash initiating signal from the operative device for operation of said initiating means;

a terminal connectable with the operative device; and

means for reading a data signal appearing at said terminal to determine whether or not said initiating means operates in response to the flash initiating signal.

34. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device;

means for receiving information from the operative device through said second terminal;

means for automatically terminating flash light emission by said emitting means when an object is illuminated to an expected level;

means for manually disabling the operation of said automatically terminating means; and

means for reviving the operation of said automatically terminating means in accordance with the information received by said receiving means even if said disabling means is manually operated.

35. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device; and

means for receiving information from the operative device through said second terminal,

wherein said initiating means includes first means for directing said emitting means to emit flash light in instant response to the flash initiating signal, second means for directing said emitting means to emit flash light in response to the flash initiating signal with a predetermined delay, and means for selecting between said first and second directing means in accordance with the information received by said receiving means.

36. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device;

means for receiving information from the operative device through said second terminal;

means for terminating flash light emission by said emitting means;

means for generating data when an expected illumination by the flash light is attained; and

means, responsive to said receiving means, for restraining said generating means from generating the data when it is informed that another electronic flash device is operative in the system to emit another flash of light with a delay.

37. The electronic flash device as claimed in claim 36 further comprising another means for generating data when an expected illumination by the second mentioned flash light is attained with said restraining means operative.

38. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device;

means for receiving informations from the operative device through said second terminal;

means for calculating indicative information relating to an object distance in flash photography in accordance with information received by said. receiving means;

means, responsive to said calculating means, for indicating the indicative information; and

means, responsive to said receiving means, for prohibiting said indicating means from indicating the indicative information when it is informed that another electronic flash device is operative in the system to emit another flash light with a delay.

39. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device;

means for receiving information from the operative device through said second terminal;

means for calculating indicative information relating to an object distance in flash photography in accordance with information received by said receiving means;

means, responsive to said calculating means, for indicating the indicative information; and

means for preparing fixed information to be substitutionally utilized by said calculating means in case said receiving means fails to receive information through said second terminal.

40. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device; and

means, responsive to the flash initiating signal, for sequentially sending two light measurement controlling signals through said second terminal.

41. The electronic flash device as claimed in claim 40, wherein said sending means includes means for forming a signal changing from a first to second level and returning to the first level as the first one of the two light measurement controlling signals, and changing again to the second level followed by returning again to the first level as the second one of the two light measurement controlling signals.

42. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for initiating flash light emission by said emitting means; and

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

wherein said emitting means includes first and second electronic flash tubes, and said initiating means includes first means for directing said first electronic flash tube to emit flash light in instant response to the flash initiating signal, and second means for directing said second electronic flash tube to emit flash light in response to the flash initiating signal with a predetermined delay, which is longer than the time taken for said first electronic flash tube to complete flash light emission with its maximum available electric power.

43. The electronic flash device as claimed in claim 42, further comprising means for adjusting a light emitting direction of said first electronic flash tube, and means, responsive to said adjusting means, for inhibiting said second directing means from directing said second electronic flash tube to emit flash light when the light emitting direction of said first electronic flash tube is the same as that of said second electronic flash tube.

44. The electronic flash device as claimed in claim 43, further comprising a second terminal connectable with the operative device, means for receiving information from the operative device through said second terminal, means for calculating an indicative information relating to an object distance in flash photography in accordance with information received by said receiving means, said calculating means being adapted to calculate the indicative information with respect to said first electronic flash tube with said inhibiting means operative and with respect to said second electronic flash tube with said inhibiting means inoperative, and means, responsive to said calculating means, for indicating the indicative information.

58. The electronic flash device as claimed in claim 42. further comprising means for adjusting the relation of the light emitting directions between the first and second electronic flash tubes.

60. The electronic flash device as claimed in claim 58, further comprising means, responsive to said adjusting means, for making said second electronic flash tube also respond to said first directing means in place of said second directing means when the light emitting direction of said first electronic flash tube is the same as that of said second electronic flash tube, so that both the first and second electronic flash tubes initiate flash light emission simultaneously, whereby said second directing means is effective to direct the second electronic flash tube when the light emitting direction of said first electronic flash tube is different from that of said second electronic flash tube.

45. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electric power for operation of said emitting means;

means for checking the level of the stored electric power;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

a second terminal connectable with the operative device for mutual communication therewith;

means for serially forwarding data descriptive of electronic flash device conditions to be transmitted to the operative device through said second terminal;

means for serially receiving information from the operative device through said second terminal for operation of the electronic flash device;

a third terminal connectable with the operative device for receiving a train of clock pulses from the operative device for operation of said forwarding means and said receiving means; and

means, responsive to the clock pulses, for intermittently serially forwarding the data at a predetermined sequence in the operation of said forwarding means, wherein said receiving means includes means for receiving information from the operative device to said second terminal during the intermission caused by said means for intermittently forwarding data.

46. The electronic flash device as claimed in claim 45, further comprising means for making said forwarding means cease to forward the data after the intermission in accordance with the information received by said receiving means.

47. The electronic flash device as claimed in claim 45, wherein said forwarding means includes means for outputting, directly before the intermission, data representing that the electronic flash device is a dedicated one in the flash photographing system, the data being formed as a low level signal to prevent any undesirable influence on information to be received by said receiving means in the succeeding intermission.

48. In a flash photographing system, a controlling device connectable to a camera for controlling a first electronic flash device having first to third terminals connectable to the controlling device and a second electronic flash device directly connectable to the camera, comprising:

fourth to sixth terminals connectable with the first to third terminals of the first electronic flash device, respectively;

seventh to ninth terminals connectable with the camera;

means for transmitting a flash initiating signal from said seventh terminal to said fourth terminal;

means for transmitting a train of clock pulses from said ninth terminal to said sixth terminal;

means for serially receiving data descriptive of the first electronic flash device through said fifth terminal and data descriptive of the second electronic flash device through said eighth terminal in response to the clock pulses received through said ninth terminal;

means for determining the manner of flash light emission of the first and second electronic flash devices in accordance with said data receiving means; and

means for serially forwarding information representative of the manner of flash light emission to the first electronic flash device through said fifth terminal and to the second electronic flash device through said eighth terminal, respectively, in response to the clock pulses received through said ninth terminal.

49. The controlling device as claimed in claim 48, wherein said determining means includes means for transmitting, by way of said forwarding means, different information to the first and second electronic flash devices to carry out respective flash light emissions at different times in response to the same flash initiating signal, when said data receiving means is informed that both the first and second electronic flash devices are operative.

50. The controlling device as claimed in claim 49, further comprising means for manually setting a simultaneous occurrence of multiple flash light emissions, and said transmitting means is adapted to transmit the same information to both the first and second electronic flash devices to simultaneously carry out respective flash light emissions with said manually setting means operated.

51. The controlling device as claimed in claim 48, further comprising means for determining the total conditions of the first and second electronic flash devices in accordance with said data receiving means, and means for serially informing the camera of the determined total conditions of the first and second electronic flash devices through said eighth terminal in response to the clock pulses received through said ninth terminal.

52. In a flash photographing system, a controlling device connectable to a camera for controlling a plurality of electronic flash devices each capable of generating data representing a condition ready for flash light emission and responding to a flash initiating signal originated from the camera, comprising:

means, responsive to the data from respective electronic flash devices, for detecting that all of the electronic flash devices generate the data;

means for informing the respective electronic flash devices of an order to emit flash light in response to the flash initiating signal only when said detecting means detects that all of the electronic flash devices generate the data; and

means, responsive to said detecting means, for informing the camera of a fact that the whole system is ready for flash light emissions.

53. In a flash photographing system, a controlling device connectable between a camera and an electronic flash device, comprising:

a terminal connectable to the camera for receiving a flash initiating signal;

means for detecting that at least another electronic flash device is effective in the system to emit flash light in response to the flash initiating signal prior to the flash light emission by the first mentioned electronic flash device;

means, responsive to said detecting means, for directing the first mentioned electronic flash device to emit flash light in response to the flash initiating signal with a predetermined delay.

54. In a flash photographing system, a camera operative with an electronic flash device in the system, comprising:

a terminal for receiving first and second light measurement controlling signals originated in the electronic flash device for flash photography;

means for measuring light upon emission of flash light including means for integrating measured light, first means for starting the integration in response to the first light measurement controlling signal and for producing a first flash terminating signal when the integrated amount reaches a predetermined portion of a required amount, and second means for restarting the integration in response to the second light measurement controlling signal and for producing a second flash terminating signal when the integrated light reaches the remainder of the required amount; and

means for forwarding the first and second flash terminating signals toward the electronic flash device.

55. The camera as claimed in claim 54, wherein said measuring means further comprises third means for starting the integration in response to the first light measurement controlling signal to continue the integration regardless of the second light measurement controlling signal with the first flash terminating signal not produced and for producing the second flash terminating signal when the integrated light reaches the full required amount.

56. The camera as claimed in claim 54, wherein said measuring means further comprises fourth means for starting the integration in response to the first light measurement controlling signal and for producing the first flash terminating signal when the integrated amount reaches the full required amount, and means for effecting said fourth starting and producing means in place of said first starting and producing means with the second flash terminating signal unnecessary.

57. In a flash photographing system, a camera operable with an electronic flash device in the system, comprising:

a terminal for receiving an information indicating that a plurality of flash light emissions serially occur for one exposure in the system;

first means for setting a first flash synchronized exposure time; and

second means for setting, in place of the first flash synchronized exposure time, a second flash synchronized exposure time greater than the first one in response to the information received through said terminal.

59. In a flash photographing system, an electronic flash device connectable to a device operative with the electronic flash device in the system, comprising:

means for emitting flash light;

means for storing electronic power for operation of said emitting means;

means for initiating flash light emission by said emitting means;

a first terminal connectable with the operative device for receiving a flash initiating signal from the operative device for operation of said initiating means;

said emitting means includes first and second electronic flash tubes, and said initiating means includes first means for directing said first electronic flash tube to emit flash light in instant response to the flash initiating signal, and second means for directing said second electronic flash tube to emit flash light in response to the flash initiating signal;

means for adjusting the relation of the light emitting directions between the first and second electronic flash tubes; and

means, responsive to said adjusting means, for making said second electronic flash tube also respond to said first directing means when the light emitting direction of said first electronic flash tube is the same as that of said second electronic flash tube, so that both said first and second electronic flash tubes initiate flash light emission at the same time.