Flash device having flat emission mode

Claim 2

A flash photography system having a camera control circuit and a flash emission control circuit, said flash photography system comprising: a communication line for performing communication between said camera control circuit and said flash emission control circuit, said communication line including a clock line for a clock pulse, data communication being performed between said camera control circuit and said flash emission control circuit in synchronism with the clock pulse on said clock line, wherein said flash emission control circuit generates an emission command to start a light emitting operation by detecting a change in signal on said clock line after predetermined data has been communicated by said data communication.

Claim 3

A flash photography system according to claim 1, wherein said predetermined data is data indicative of a flat emission.

Claim 4

A flash photography system according to claim 2, wherein said flash emission control circuit starts a light emitting operation in response to a signal from an X-sync contact of a camera when the flat emission is not indicated.

Claim 5

A flash photography system according to claim 2, wherein said camera control circuit communicates the data indicative of the flat emission when a shutter time is shorter than a synchronizing time.

Claim 6

A flash photography system according to claim 1, wherein said change in signal is a rising or lowering of the clock pulse.

Claim 7

A flash photography system according to claim 1, wherein said communication line includes a data line for said data.

Claim 8

A flash photography system according to claim 1, wherein said camera control circuit is provided at a camera body and said flash emission control circuit is provided at a flash device mounted on the camera body, and wherein said camera control circuit and said flash emission control circuit are connected to each other through said communication line when the flash device is mounted on the camera body.

Claim 9

A flash device comprising: serial clock input means for inputting a serial clock pulse for performing a serial communication with a camera body; serial data input means for inputting data from the camera body in synchronism with the serial clock pulse; serial data output means for outputting data in synchronism with the serial clock pulse; signal detecting means for detecting a flash emission start signal which becomes active in synchronism with a fully opened state of a shutter; change detecting means for detecting a change of the serial clock pulse inputted to said serial clock input means next to a signal indicative of an emission mode received from the camera body through said serial data input means by the serial communication; recognition means for recognizing a state detected by said change detecting means as an emission start signal for a specific emission mode; and emission control means for starting an emission independent of the flash emission start signal on the basis of an output of said recognition means.

Claim 10

A flash device comprising: serial clock input means for inputting a serial clock pulse for performing a serial communication with a camera body; serial data input means for inputting data from the camera body in synchronism with the serial clock pulse; serial data output means for outputting data in synchronism with the serial clock pulse; signal detecting means for detecting a flash emission start signal which becomes active in synchronism with a fully opened state of a shutter; change detecting means for detecting a change of the serial clock pulse inputted to said serial clock input means next to a signal indicative of an emission mode received from the camera body through said serial data input means by the serial communication; recognition means for recognizing a state detected by said change detecting means as an emission start signal for a specific emission mode; and emission control means for starting an emission independent of the flash emission start signal on the basis of an output of said recognition means.

Claim 11

A flash device according to claim 8, wherein said specific emission mode is a flat emission where a flash light is emitted substantially at a constant emission intensity for a predetermined time period.

Claim 12

A flash device according to claim 8, wherein said change of the serial clock pulse is a lowering edge or rising edge.

Claim 13

A flash device according to claim 8, wherein said change detecting means is an interrupt generating means generated by a first lowering edge or rising edge of the serial clock pulse for causing a microcomputer to perform an interrupt processing.

Claim 14

A flash device according to claim 8, wherein, when said signal indicative of an emission mode represents the specific emission mode, said recognition means recognizes as the emission start signal a change of the serial clock pulse inputted next to receiving of said signal.