JP4871601B2 - Flash device, camera and flash photographing system - Google Patents

Description

The present invention relates to a flash device, a camera, and a flash photographing system that perform light emission instructions to other flash devices by optical communication .

A system for controlling the light emission of the slave flash device using the light emission of the master flash device has been proposed in Patent Document 1, for example. In this system, for example, the light emission amount (light emission intensity, light emission time, etc.) of the master flash device is controlled according to the amount of information to be transmitted, such as the number of lamps of the slave flash device and the light emission mode.
Japanese Patent Laid-Open No. 11-190872

  In the above-mentioned Patent Document 1, synchronous light emission (fire pulse) is required to synchronize light emission with the slave flash device after wireless transmission light emission. In addition, when emitting light for shooting after wireless transmission light emission (when front light emission is ON), synchronize with light emission for shooting (main light emission), and do not emit light for shooting after wireless transmission light emission (front light emission) In the case of OFF), only the slave flash device is made to emit light. Therefore, conventionally, light is emitted with the same minute light amount as the communication pulse as the synchronous light emission.

  However, when the front light is turned off and the subject is at a short distance or the recording medium sensitivity (ISO sensitivity) is high, if the fire pulse is larger than the dimming light amount, there is a problem that overexposure is taken. .

(Object of invention)
An object of the present invention is to provide a flash device, a camera, and a flash photographing system capable of preventing overexposure and providing an image with proper exposure.

In order to achieve the above object, the flash device of the present invention is a flash device that performs a light emission instruction to another flash device by optical communication, and performs optical communication with the other flash device by emitting light. When the light emitting means and the light emitting means do not emit light to illuminate the subject, the light emission amount of the light emitting means during optical communication is controlled based on at least one of the subject distance and the photographing sensitivity of the attached camera. It possesses a light emission control means, wherein the light emission control means may control, when the shooting sensitivity is higher second photographic sensitivity than the first imaging sensitivity, or the subject distance is closer than the first distance In the case of the second distance, the light emission amount of the light emitting means when performing optical communication is reduced as compared with the case where the photographing sensitivity and the subject distance do not satisfy any of the conditions .

Also in order to achieve the above object, a camera of the present invention is a camera for emission instruction to the flash device in optical communication, a light emitting unit for optical communication to the flash device by emitting the A light emission control means for controlling a light emission amount of the light emission means when performing optical communication based on at least one of a subject distance and a photographing sensitivity of the camera when the light emission means is not caused to emit light to irradiate the subject ; If Yes, and the light emission control means may control, when the shooting sensitivity is higher second photographic sensitivity than the first imaging sensitivity, or the subject distance is a second distance shorter than the first distance The light emission amount of the light emitting means when performing optical communication is lower than when the photographing sensitivity and the subject distance do not satisfy any of the conditions .

Similarly, in order to achieve the above object, the flash photographing system of the present invention is a flash photographing system having a camera and a flash device and performing a light emission instruction from the camera to the flash device by optical communication, and emits light. In this way, the light emitting means for performing optical communication with the flash device and the optical communication based on at least one of the subject distance and the photographing sensitivity of the camera when the light emitting means does not emit light to illuminate the subject. have a, a light emission controller for controlling light emission of said light emitting means when said light emission control means may control, when the shooting sensitivity is higher second photographic sensitivity than the first imaging sensitivity, or the When the subject distance is a second distance that is closer than the first distance, the light emission amount of the light emitting means when performing optical communication than when the photographing sensitivity and the subject distance do not satisfy any of the conditions Characterized in that the lower.

According to the present invention, it is possible to prevent overexposure and provide an image with proper exposure .

  The best mode for carrying out the present invention is as shown in Examples 1 to 3 below.

  FIG. 1 is a diagram showing a master flash device (hereinafter referred to as a transmitter) according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing a camera according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing a slave flash device (hereinafter referred to as a receiver) according to Embodiment 1 of the present invention. The flash photography system is configured by the devices shown in FIGS.

  First, the configuration of the transmitter will be described with reference to FIG. Reference numeral 101 denotes a battery as a power source, reference numeral 102 denotes a booster circuit that boosts the voltage of the battery 101, and reference numeral 103 denotes a main capacitor that stores the output of the booster circuit 101. An existing trigger circuit 104 excites the discharge tube 105 to emit light, and is connected to an output terminal TRIG of a microcomputer (hereinafter referred to as a transmitter microcomputer) 109 on the transmitter side. Reference numeral 105 denotes a discharge tube that converts electric energy of the main capacitor 103 into light, and 106 denotes a light emission control circuit that controls light emission of the discharge tube 105. Reference numerals 107 and 108 denote resistors for dividing the charging voltage of the main capacitor 103, and the voltage dividing point is connected to the terminal ADIN of the transmitter microcomputer 109.

  The transmitter microcomputer 109 controls various operations of the transmitter such as light emission control, light emission amount, and light emission mode setting. Reference numeral 110 denotes a setting member for setting the light emission amount and the light emission mode. Reference numeral 111 denotes a light-emitting diode (hereinafter referred to as LED) for displaying the completion of charging, which indicates that the charging voltage of the main capacitor 103 has reached the light-emittable voltage, and is connected to a terminal CHGLED which is an open drain port of the transmitter microcomputer 109. Yes. A resistor 112 is connected between the power supply (VCC) and the LED 111. A display unit 113 displays a state set by the setting member 110. Reference numeral 114 denotes a D / A converter that outputs a DA output (outputs a signal for stopping light emission) to a non-inverting input of a comparator 116 described later in accordance with data from a terminal DAOUT of the transmitter microcomputer 109. Reference numeral 118 denotes a light emission amount monitor for detecting the light emission intensity, which receives light emitted from the discharge tube 105 and outputs a voltage corresponding to the light emission intensity. The light emission amount monitor unit 118 is connected to the inverting input of the comparator 116.

A constant voltage circuit 115 supplies a constant voltage (VCC) from the battery 101 and supplies power to the transmitter microcomputer 109. Reference numeral 116 denotes a comparator whose output is connected to an AND gate 117 described later. Reference numeral 117 denotes an AND gate, and an input other than that connected to the output of the comparator 116 is connected to the terminal STSP of the transmitter microcomputer 109, and its output is connected to the light emission control circuit 106 and the terminal FCIN of the transmitter microcomputer 109. . Reference numeral 120 denotes a terminal group for interface with the camera, which is connected to terminals S0 to S5 of the transmitter microcomputer 109. It is also connected to a terminal group 12 of a camera microcomputer 3 to be described later.

  The light emission amount monitor 118, the D / A converter 114, the comparator 116, the AND gate 117, and the transmitter microcomputer 109 constitute the light emission control means of the present invention.

  Next, a schematic configuration of the camera will be described with reference to FIG. A battery 1 is a power source of the camera. Reference numeral 2 denotes a power supply circuit, for example, a known voltage circuit that outputs a constant voltage even when the voltage of the battery 1 changes. This voltage is supplied to each circuit block. Reference numeral 3 denotes a camera microcomputer, which is a one-chip IC circuit with a built-in microcomputer including, for example, a CPU, ROM, RAM, input / output control (I / O CONTROL) circuit, multiplexer, timer circuit, and the like. This camera microcomputer 3 controls the camera system by software. Note that an EEPROM may be incorporated in the camera microcomputer 3.

  Reference numeral 4 denotes a setting member for setting camera information, which includes setting of information on camera mode, exposure information (aperture, shutter speed), and film sensitivity (ISO). Here, a switch detection unit is included, and the state of the switch is constantly detected and transmitted to the camera microcomputer 3 as a signal. The setting member 4 includes, for example, a switch SW1 (for example, a half-press switch) for preparation for photographing and a switch SW2 (for example, a full-press switch) for photographing. Further, a switch group for controlling the camera such as an exposure setting switch (aperture, shutter setting switch), a mode switch (program mode, manual mode, etc.) is also included. Reference numeral 5 denotes a display unit for displaying information set by the setting member 4 and results calculated by the camera microcomputer 3.

  Reference numeral 6 denotes a photometry circuit that measures the luminance of the subject, and transmits data (signal) necessary for exposure to the camera microcomputer 3 in order to determine an appropriate exposure (shutter speed, aperture). The photometry circuit 6 also has a function of measuring the amount of strobe light during strobe preliminary light emission. Specifically, it is also a photometric circuit for performing main light emission by calculating the amount of strobe light during preliminary light emission by the camera microcomputer 3.

  7 is a known dimming circuit, which detects light reflected on the subject by stroboscopic irradiation. In addition, a strobe reflected light detection circuit for outputting a signal for stopping light emission when the exposure is appropriate to the transmitter microcomputer 109 via the contact group 12 that is an interface between the camera microcomputer 3 and the transmitter microcomputer 109 is included. .

Reference numeral 8 is a known distance measuring circuit , for example, an active system that projects light from the camera side and receives reflected light from the subject to obtain distance information. Alternatively, it may be a passive focus detection circuit composed of a line sensor corresponding to the screen and a drive circuit. Specifically, the accumulation control of the line sensor is performed by the drive circuit, the camera microcomputer 3 receives the image signal of each line sensor, and calculates to which position the subject is focused by the existing phase difference detection method. It is to detect.

  In the distance measuring circuit 8, for example, at the time of distance measurement, a part of the light beam condensed by the photographing lens (not shown) is transmitted to a part of the main mirror, and a line sensor (not shown) is transmitted by the sub mirror (not shown). And distance measurement is performed, and a distance signal is output to the camera microcomputer 3. The value measured by the line sensor is the defocus amount, and the absolute distance is calculated from the absolute position of the focus lens at the time of focusing. The actual focusing operation is performed by driving a focus lens group (not shown) in the photographing lens (not shown) by a focus driving mechanism (not shown) from the defocus amount and the lens-specific parameters.

  Reference numeral 9 denotes a focal length detection circuit for transmitting the focal length of a photographing lens (not shown) to the camera microcomputer 3 side. The focal length detection circuit 9 focuses fixed data if the photographing lens (not shown) is a single focus lens, and data corresponding to the zoom position detected by a known zoom encoder (not shown) if it is a zoom lens. Output as a distance signal.

  An EEPROM (electrically erasable program writable ROM) 10 is connected to the camera microcomputer 3. Setting information necessary for the camera is written in the EEPROM 10. Reference numeral 11 denotes an X contact, which is a switch for transmitting the flash emission timing to the transmitter side in synchronization with the operation of a shutter (not shown). One end of the X contact 11 is connected to the terminal S4 of the transmitter microcomputer 109 via a contact group 12 described later, and the other end is at the GND level.

  A contact group 12 serves as an interface with the transmitter microcomputer 109 and transmits signals between the camera microcomputer 3 and the transmitter microcomputer 109, and corresponds to an accessory shoe.

  Next, terminals serving as an interface in the camera microcomputer 3 will be described. SCK is a terminal that outputs a synchronous clock for serial communication with the transmitter microcomputer 109. SDO is a serial data output terminal for performing serial communication with the transmitter microcomputer 109. The SDI is a serial data input terminal for performing serial communication with the transmitter microcomputer 109. SCHG is a terminal for detecting the completion of charging of a known main capacitor (not shown) that stores strobe light emission energy. X is a terminal connected to the terminal S4 of the transmitter microcomputer 109, and GND is a terminal connected to the terminal S5 of the transmitter microcomputer 109. The terminal SCK is connected to the terminal S0 of the transmitter microcomputer 109, and the terminal SDO is connected to the terminal S1 of the transmitter microcomputer 109. The terminal SDI is connected to the terminal S2 of the transmitter microcomputer 109, and the terminal SCHG is connected to the terminal S3 of the transmitter microcomputer 109.

  Next, the configuration of the receiver will be described with reference to FIG. In the first embodiment, one or a plurality of receivers are provided for one transmitter.

In FIG. 3, reference numeral 201 denotes a battery as a power source. Reference numeral 202 denotes a booster circuit that starts boosting the voltage of the battery 201 by a signal CHG from a receiver-side microcomputer (hereinafter referred to as a receiver microcomputer) 209, and 203 is a main capacitor that stores the output of the booster circuit 202. Reference numeral 204 denotes a trigger circuit that excites the discharge tube 205 to emit light, and is connected to the output terminal TRIG of the receiver microcomputer 209. Reference numeral 205 denotes a discharge tube that converts electric energy of the main capacitor 203 into light, and 206 denotes a light emission control circuit that controls light emission of the discharge tube 205.

  The receiver microcomputer 209 controls various operations of the receiver such as light emission control, light emission amount, and data analysis from the transmitter. Reference numeral 210 denotes a setting member for setting the light emission amount and the light emission mode on the receiving side. However, if a communication command comes from the transmitter, it will be followed. Reference numeral 211 denotes a charging completion display LED for displaying that the charging voltage of the main capacitor 203 has reached the light emission possible voltage, and is connected to a terminal CHGLED which is an open drain port of the receiver microcomputer 209. A resistor 212 is connected between the battery 210 and the LED 211. Reference numeral 213 denotes a display unit that displays the state set by the setting member 210 or the result of the communication command of the transmitter.

  A D / A converter 214 outputs a DA output to the non-inverting input of the comparator 216 in accordance with data received from the terminal DAOUT of the receiver microcomputer 209. A light emission amount monitor unit 218 receives light emitted from the discharge tube 205 and outputs a voltage corresponding to the integration amount to the inverting input of the comparator 216. Reference numeral 216 denotes a comparator whose output is output to an AND gate 217 described later. Reference numeral 217 denotes an AND gate, and an input terminal other than that connected to the output of the comparator 216 is connected to a terminal STSP of the receiver microcomputer 209, and its output is connected to the light emission control circuit 206.

  A constant voltage circuit 215 supplies a constant voltage (VCC) from the battery 201, and supplies power to the receiver microcomputer 209. An optical communication light receiving unit 220 receives optical communication data from the transmitter. Reference numeral 221 denotes a slave ID setting unit that indicates which lamp of the slave the receiver is set to.

  Next, details of the optical communication light receiving unit 220 will be described with reference to FIG. 220a is a photodiode, the cathode is connected to the power supply, and the anode is connected to the resistor 220b. A connection point between the resistor 220b and the photodiode 220a is connected to a non-inverting input of the comparator 220e. The resistors 220c and 220d divide the reference voltage, and the voltage dividing point is connected to the inverting input of the comparator 220e. The output of the comparator 220e becomes the output of the optical communication light receiving unit 220 and is sent to the receiver microcomputer 209.

  Next, the specific operation of the camera microcomputer 3 shown in FIG. 2 will be described with reference to the flowcharts of FIGS.

  When a power switch (not shown) is turned on and the camera microcomputer 3 becomes operable, the camera microcomputer 3 starts operation from step S1 in FIG.

  First, in step S1, the camera microcomputer 3 initializes its own memory and port. In the next step S2, it is checked whether or not the switch SW1 included in the setting member 4 for setting camera information is turned on. If it is off, the process stays in step S2. Thereafter, when the switch SW1 is turned on, the process proceeds to step S3.

  In step S3, the camera information set by the setting member 4 is input. This camera information includes camera mode, exposure information (aperture, shutter speed), and film sensitivity (ISO). Furthermore, the focal length information of the photographing lens, distance measurement (focus detection), and optical information necessary for photometry are also included. In the next step S4, it is checked via the terminal group 12 (see FIG. 2) and the terminal group 120 (see FIG. 1) whether the transmitter of FIG. 1 is attached to the camera. As a result, if the transmitter is attached to the camera, the process proceeds to step S5, and the strobe mode is set. If the transmitter is not attached, the process proceeds to step S6, and the non-strobe mode is set.

  In the next step S7, defocus information is obtained from information from the distance measuring circuit 8. In the next step S8, the driving amount of the focus lens (not shown) is calculated based on the defocus information obtained in step S7, and the driving of the focus lens is performed on the photographing lens side (not shown). Order the microcomputer. As a result, the photographing lens is brought into focus. In the subsequent step S9, the photometric output from the photometric circuit 7 is input to obtain the luminance information of the subject.

  In the next step S10, it is determined whether or not the strobe mode is set. If the strobe mode is set, the process proceeds to step S11, and information necessary for strobe light emission via the terminal group 12 and the terminal group 120 is shown in FIG. To the transmitter. At this time, the aperture, shutter speed information, and film sensitivity (ISO) information are also transmitted, and the process proceeds to step S12. On the other hand, if the mode is non-strobe, the process immediately proceeds to step S12.

  In step S <b> 12, it is determined whether a charging completion signal is input from the transmitter microcomputer 109 to the camera microcomputer 3 via the terminal group 120 and the terminal group 12. As a result, if the charging is completed, the process proceeds to step S13, and the shutter speed (described as Tv in the flowchart of FIG. 5) and the aperture value (described as Av in the flowchart of FIG. 5) suitable for performing flash photography are set as described above. This is determined based on the photometric output obtained in step S9. If the charging is not completed, the process proceeds from step S12 to step S14, and a shutter speed and an aperture value suitable for photographing with natural light are determined based on the photometric output obtained in step S9.

  When the process of step S13 or step S14 is executed, the process proceeds to step S15 in any case.

  In step S15, it is checked whether or not the switch SW2 included in the setting member 4 is turned on. If it is off, the process returns to step S2 to repeat the processing from step S2 onward. If it is on, the process proceeds to step S16 in FIG.

  In step S16 of FIG. 6, it is determined whether or not the strobe mode is set. If the strobe mode is set, the process proceeds to step S17. If the strobe mode is not set, the process immediately proceeds to step S20. If the strobe mode is set and the process proceeds to step S17, information necessary for strobe light emission is communicated with the transmitter microcomputer 109 via the terminal group 12 and the terminal group 120, and a preliminary light emission start signal is transmitted to the transmitter microcomputer 109. Output for. Thereby, preliminary light emission is started on the transmitter side in FIG. The amount of light emission thereafter depends on the light emission instruction value calculated by the camera microcomputer 3. In the subsequent step S18, the light reflected from the subject after the preliminary light emission is detected by the photometry circuit 7 or the light control circuit 6, and the main light emission amount is calculated by the camera microcomputer 3. In step S 19, communication of information on the main light emission amount necessary for strobe light emission is performed to the transmitter microcomputer 109 via the terminal group 12 and the terminal group 120.

  In the next step S20, a motor (not shown) is driven to raise a main mirror and a sub mirror (not shown). In the next step S21, information on the aperture value determined in step S13 or step S14 is sent to the photographic lens side to command driving of the aperture. Thereby, the narrowing-down operation is performed. In the next step S22, the shutter front curtain is caused to travel. Thereby, exposure is started. In the subsequent step S23, counting of the shutter closing time (time until the trailing curtain travel is started) is started based on the shutter speed information determined in step S13 or step S14.

  In the next step S24, it is determined whether or not the strobe mode is set in steps S4 and S10, and it is determined whether or not the completion of charging is determined in step S12. As a result, if it is the strobe mode and the charging is completed, the process proceeds to step S25. In step S25, communication of information necessary for strobe light emission, that is, a strobe light emission start signal is output to the transmitter microcomputer 109 via the terminal group 12 and the terminal group 120. Thereby, the main flash of the strobe is started. The subsequent main light emission amount is based on the light emission instruction value calculated in step S18. Thereafter, the process proceeds to step S26, waits for the count of the shutter closing time started in step S23 to end, and proceeds to step S28 when the counting of the closing time ends.

  If it is determined in step S24 that the flash mode is not set or the charging is not completed, the process proceeds to step S27. In step S27, the process waits for the count of the shutter closing time started in step S23 to end. When the counting of the closing time ends, the process proceeds to step S28.

  In the next step S28, the rear curtain of the shutter is caused to travel. This completes the exposure. In a succeeding step S29, the photographing lens side is instructed to open the aperture. In the next step S30, the motor (not shown) is driven to lower the main mirror and sub mirror (not shown) and the shutter is charged. In step S31, a motor (not shown) is driven to wind the film.

  After the above operation, the process returns to step S1 in FIG. 3, and the same operation is repeated again.

  In the first embodiment described above, a camera using a film as a recording medium is assumed. However, even in a camera using an electronic image sensor (CCD, CMOS) instead of a film, the process in step S31 in FIG. The operation is exactly the same except that the operation is changed to an operation for processing a captured image instead of a winding operation by a motor. In this case, sensitivity information indicating the gain of the output signal of the electronic image sensor is used instead of film sensitivity (ISO) as camera information indicating the recording medium sensitivity.

  In addition, an example in which a flash discharge tube is used as the flash light emitting unit has been shown, but a light emitting diode such as a white light emitting diode may be used instead of the flash discharge tube.

  Above, description of the specific operation | movement in the camera microcomputer 3 is complete | finished.

  Next, the operation on the transmitter side in FIG. 1, that is, the specific operation in the transmitter microcomputer 109 will be described with reference to the flowcharts in FIGS.

  When a power switch (not shown) is turned on, the transmitter microcomputer 109 starts its operation, and first initializes its own memory and port in step S101. In the next step S102, the booster circuit 102 is operated to boost the voltage of the battery 101 to a high voltage. After boosting, charge energy is stored in the main capacitor 103. In the next step S103, the information (including the number of light-emitting lamps) set by the setting member 110 is read. In subsequent step S104, information (aperture, shutter speed information, film sensitivity (ISO) information) necessary for strobe light emission received from the camera microcomputer 3 via the terminal group 12 and the terminal group 120 is confirmed.

  In the next step S105, “IMAX” and the transmission data D0 of the first byte are set according to the number of the lamps read in step S103 from FIG. 16, and the set light emission amount transmission data D1 is set from FIG. ~ Set DIMAX. For example, when a maximum of three slaves are set and 1/4, 1/8, and 1/16 light emission are set, respectively, from FIG. 16, IMAX = 3, “D0 = 10000010”, and from FIG. 18, “D1 = “10000101”, “D2 = 10000111”, and “D3 = 10001001” are set. Also, from FIG. 17, the output from the terminal DAOUT is set according to the film (ISO) sensitivity read in step S103 or step S104. In the configuration of transmission data, bit 7 (most significant bit) is a start bit that is a reference for optical transmission, and is always 1. Transmission is performed in the order of bit 7 to bit 0.

  Returning to FIG. 7, in the next step S106, the charging voltage of the main capacitor 103 divided by the resistors 107 and 108 is A / D converted, and the charging voltage (VMC) of the main capacitor 103 is read. In the next step S107, according to FIG. 17, the data of the emission intensity to be set to the D / A converter 114 is output from the film (ISO) sensitivity set in the above step S105. The D / A converter 114 outputs a voltage corresponding to the received data to the non-inverting input of the comparator 116. Data from the transmitter microcomputer 109 to the D / A converter 114 shown in FIG. 17 is expressed in hexadecimal numbers, and ranges from “00H to FFH”. The larger the data, the greater the output of the D / A converter 114. That is, the light emission intensity of the optical transmission pulse increases. For example, in the case of ISO 800, 90 is set in the D / A converter 114.

  In the next step S108, it is determined whether or not the charging voltage (VMC) of the main capacitor 103 is equal to or higher than the light emission possible charging voltage (VT) (VMC ≧ VT). If VMC <VT, the process proceeds to step S110. In step S110, the terminal CHGLED which is an open drain port is set to High (OPEN) in order to display the light emission inhibition state, the charging completion display LED 111 is turned off, and the process returns to step S103.

  On the other hand, if it is determined in step S108 that VMC ≧ VT, the process proceeds to step S109, where the terminal CHGLED which is an open drain port is set low to display the light emission permission state, and the charging completion display LED 111 is set. Light up. Then, in the next step S111, it is determined whether or not a light emission start signal is input from the camera. If no light emission start signal is input, the process returns to step S103. If a light emission start signal has been input, the process proceeds to step S112 to call a subroutine for optical communication processing to a receiver which is a slave flash device. Thereafter, the process returns to step S103.

  Next, the optical communication processing subroutine executed in step S112 will be described with reference to the flowchart of FIG.

  First, in step S201, 0 is set to a variable I indicating how many bytes are to be transmitted. In the next step S202, it is determined whether or not I = 0. If I = 0, the process proceeds to step S203, where the data D0 of the first byte is set in the transmission buffer for optical communication, and step S211. Proceed to If I = 0, the process proceeds from step S202 to step S204, where it is determined whether I = 1. As a result, if I = 1, the process proceeds to step S205, the data D1 of the second byte is set in the communication buffer for optical communication, and the process proceeds to step S211.

  Hereinafter, the data DI (0 ≦ I ≦ 4) to be sent to the optical communication buffer is set up to 5 bytes (IMAX = 4) of the maximum number of bytes defined in the optical communication format (steps S206 to S210). .

  In the next step S211, a variable BI indicating how many bits are processed in one byte of optical communication is set to 0, and a 1-byte communication end flag is set to 0. Then, in the next step S212, the timer interruption at the communication bit interval is permitted. As a result, the transmitter microcomputer 109 receives a timer interrupt at the set interval, and can perform an interrupt process at the set interval.

  In the next step S213, in order to determine whether or not the optical communication for one byte has been completed, it is checked whether or not the one-byte communication end flag is 1, and if not, the process waits in step S213. Thereafter, when the 1-byte communication end flag becomes 1, the process proceeds to step S214, where it is determined whether or not I ≧ IMAX, that is, whether or not the optical communication for the number of bytes set in step S105 has been completed. As a result, if I ≧ IMAX, the process proceeds to step 215, performs I = I + 1, and returns to step S202 to transmit the next byte. If I ≧ IMAX, the process proceeds to step S216, and a light emission start signal for causing the receivers that are the slave flash devices to emit light in synchronization is transmitted. This signal performs the same operation as the 1-bit light emission processing in step S303 of FIG. 9 described below. Then, the optical communication process ends, and the process returns to the main routine.

  Next, an operation for transmitting one byte of optical communication will be described with reference to FIGS. 9 and 12A. FIG. 12A shows the waveform of each part when 1-byte data “10000010” is transmitted.

  In step S212 of FIG. 8, a timer interrupt is generated by permitting a timer interrupt at a predetermined interval (communication pulse bit interval). The timer interrupt generation timing is the rise of the waveform shown in (a) of FIG.

  When the timer interrupt starts, the communication buffer is shifted to the left in step S301 in FIG. Then, in the next step S302, it is determined whether or not the bit that has been shifted and pushed out is 1. If it is 1, since 1 is output by optical transmission, the process proceeds to step S303 in which the discharge tube 105 is caused to emit light. Otherwise, 0 is output by optical transmission, and therefore the discharge tube 105 is not caused to emit light, and thus the process immediately proceeds to step S304.

  In step S303, a 1-bit light emission process described below is performed.

  First, the transmitter microcomputer 109 sets the output terminal STSP to High. At this time, since the discharge tube 105 is not emitting light, the output of the light emission amount monitor unit 118 is smaller than the output of the D / A converter 114. For this reason, the output of the comparator 116 is High, and the inputs of the AND gate 117 are both High, so that the output is also High. This is input to the light emission control circuit 106. Then, the light emission control circuit 106 forms a discharge loop of the anode of the main capacitor 103 → the discharge tube 105 → the light emission control circuit 106 → the cathode of the main capacitor 103.

At this time, the transmitter microcomputer 109 sets the output terminal TRI to High for a predetermined time to operate the trigger circuit 104 to excite the discharge tube 105 to start light emission (timing T1 in FIG. 12A). When the light emission intensity of the discharge tube 105 reaches a predetermined value or more, the output of the light emission amount monitor unit 118 and the output of the D / A converter 114 are
The output of the light emission amount monitor unit 118 ≥ the output of the D / A converter 114. Therefore, the output of the comparator 116 becomes Low. As a result, the output of the AND gate 117 also becomes Low, and the light emission control circuit 106 cuts off the discharge loop of the anode 103 of the main capacitor → the discharge tube 105 → the light emission control circuit 106 → the cathode of the main capacitor 103. Accordingly, the light emission of 1-bit communication is stopped (timing T2 in FIG. 12A).

  Further, when the transmitter microcomputer 109 detects Low after light emission of the AND gate 117 from the terminal FCIN, the transmitter microcomputer 109 sets the terminal STSP to Low and proceeds to Step S304.

  In step S304, BI = 7 is checked to determine whether the 1-byte optical communication has been completed. As a result, if the 1-byte optical communication is completed, the process proceeds to step S305, the timer interrupt is prohibited, the 1-byte communication end flag is set to 1, and the interrupt process is terminated. If 1-byte optical communication has not ended, the process advances from step S304 to step S306, and BI = BI + 1 is performed. Thereafter, the process proceeds to step S307, and the 1-byte communication is not terminated, so that the timer interrupt is not prohibited, the 1-byte communication end flag is set to 0, and the interrupt process is terminated.

  As described above, the transmitter transmits the light emission mode and the light emission amount to the receiver as light emission or non-light emission of the discharge tube 105, that is, as 1 and 0 digital data. Further, by setting the output of the D / A converter 114 in accordance with the film sensitivity (ISO) setting from the camera or the film sensitivity (ISO) setting set by the setting member 110, the emission intensity of the optical communication pulse It is possible to change.

  Next, the transmitter can be set to either a first mode in which both optical communication and light emission for photographing (hereinafter, main light emission) are performed, or a second mode in which only optical communication is performed, The case where each mode is set by the setting member 110 of FIG. 1 will be described with reference to FIGS.

  First, a case where the first mode is set and the transmitter as the master flash device performs optical communication (transmission signal) and main light emission (hereinafter, when front light emission is ON) will be described.

  FIG. 12 shows a timing chart when front light emission is ON. After transmitting data related to light emission (here, “10000010”) from the transmitter, a synchronization signal (fire pulse) is transmitted in order to emit light simultaneously with light emission from the transmitter. FIG. 12 shows a timing chart in which the fire pulse and the main light emission of the transmitter are combined for operation. Therefore, the master light emission is set together with the slave light emission at the time of shooting.

  At this time, the main light emission amount of the transmitter is determined by setting the level of the output of the D / A converter 114 set by the transmitter itself as indicated by L2 in (f) of FIG. . At this time, when the ISO sensitivity is high or at a short distance, the main light emission amount becomes a minute light amount, but the fire pulse is also made a minute light amount in the same manner, so that the influence of overexposure is small.

  Next, a conventional example when the second mode is set and the transmitter as the master flash device does not perform main light emission only by optical communication (hereinafter, when front light emission is OFF) will be described.

  FIG. 13 shows a timing chart when front light emission is OFF. After transmitting data related to light emission (here, “10000010”) from the transmitter, the transmitter does not emit light, but transmits a synchronization signal (fire pulse) to emit only light from the receiver. FIG. 13 is a timing chart in which this fire pulse (FIRE PULSE) is operated. Therefore, only the slave light emission is set at the time of shooting.

  At this time, the light emission amount of the transmitter is determined by setting the level of the output of the D / A converter set by the transmitter itself as indicated by L3 in (f) of FIG. At this time, when the ISO sensitivity is high or at a short distance, if the fire pulse that becomes a minute light amount is larger than the light amount adjusted, the overexposure is shot. This is because the fire pulse when the front light of the transmitter is off is unnecessary light emission except for synchronizing the receiver, so it is necessary to keep it at a level that does not affect the exposure. Because there is no.

  Next, a description will be given of the case of front light emission OFF in the first embodiment of the present invention. FIG. 14 shows a timing chart when the front light emission is OFF in the first embodiment. After transmitting data related to light emission (here, “10000010”) from the transmitter, the transmitter does not emit light, but transmits a synchronization signal (fire pulse) to emit only light from the receiver. FIG. 14 is a timing chart in which this fire pulse is operated. Therefore, only the slave light emission is set at the time of shooting.

  The output of the D / A converter 114 is set according to the film sensitivity (ISO) setting from the camera or the film sensitivity (ISO) setting set by the setting member 110. Thereby, the light emission intensity of the optical communication pulse itself is changed (the light emission amounts of the communication pulse and the fire pulse are reduced). For example, the output of the D / A converter 114 is determined by setting a level corresponding to a predetermined ISO sensitivity as indicated by L4 in (f) of FIG. At this time, when the ISO sensitivity is high, the amount of light emission is a very small amount of light. When the fire pulse is greater than the amount of light adjusted, overexposure will not occur.

Next, the operation on the receiver side which is the slave flash device of FIG. 3 , that is, the specific operation of the receiver microcomputer 209 will be described with reference to the flowcharts of FIGS.

  When a power switch on the receiver side (not shown) is turned on, the receiver microcomputer 209 starts the operation of the booster circuit 202 and boosts the voltage of the battery 201 to a high voltage. After boosting, charge energy is stored in the main capacitor 203.

  Here, the operation of the receiver from the reception of the optical communication pulse from the transmitter, which is the master flash device, until the receiver emits light will be described with reference to FIG. 10 and FIG. FIG. 12B shows the waveform of each part when one byte of optical communication data “10000010” is received. When the optical communication light receiving unit 220 receives an optical communication pulse by light emission from the transmitter, an interrupt is generated in the receiver microcomputer 209 (timing T3 in FIG. 12B).

  The interrupt processing for receiving the optical communication pulse will be described with reference to the flowchart of FIG. When the interruption starts, the receiver microcomputer 209 first proceeds to step S406 if the light emission permission flag is 1 (that is, if light emission is started) in step S401, and proceeds to step S402 if it is 0 (that is, if communication is started). .

  When the process proceeds to step S402 because it is the start of communication, the receiver microcomputer 209 sets 1 to the variable RBI indicating the bit number of the communication. Then, in the next step S403, interruption due to reception of the optical communication pulse is prohibited, and in subsequent step S404, the timer interrupt is permitted so as to generate a timer interrupt at an interval corresponding to the bit interval of the optical communication pulse. Then, in the next step S405, 1 is set to the least significant bit (LSB) of the reception buffer, and the interrupt process is terminated.

  On the other hand, a case will be described in which it is determined in step S401 that light emission is started and the process proceeds to step S406. In step S406, the receiver microcomputer 209 determines whether the slave ID (SID) set by the slave ID setting unit 221 is zero. If the result is 0, the process proceeds to step S407, and the light emission amount FD1 corresponding to the slave ID = 0 sent from the transmitter side by optical communication is set in the output buffer to the D / A converter 214.

  Hereinafter, in steps S408 to S412, the light emission amounts FD2 to FD4 sent from the transmitter side corresponding to the slave ID of each receiver are set in the output buffer to the D / A converter.

  In the next step S413, in order to remove the start bit, the output buffer to the D / A converter 214 is ANDed with "01111111B" (logical product is taken). Then, in the next step S414, it is determined whether or not the output buffer to the D / A converter 214 is “00000000B”. If “00000000B”, the process proceeds to step S417 in order not to emit light, and if it is not “00000000B”. Proceed to step S415.

  In step S 415, the output buffer for the D / A converter 214 is output to the D / A converter 214. Then, the process proceeds to step S416.

  Here, the light emission operation on the receiver side executed in step S416 will be described with reference to FIG. FIG. 15 shows the optical communication (D0 = 10000000, D1 = 10000011), the light emission start signal, and the waveform of each part of the receiver when one receiver performs one-half light emission. Yes.

One of the light emission amounts FD1 to FD4 corresponding to the slave ID is transmitted from the transmitter in the optical communication, and the receiver microcomputer 209 that has received this light emission amount sets the light emission amount in the D / A converter 214 (FIG. 15 (B) after T1), the terminal STSP is set to High. At this time, since the discharge tube 205 is not emitting light, the output of the light emission amount monitor unit 218 and the output of the D / A converter 214 are in the relationship of the output of the light emission amount monitor unit 218 <the output of the D / A converter 214. For this reason, the output of the comparator 216 is High, and since both inputs of the AND gate 217 are High, the output is also High. When this output is input to the light emission control circuit 206, the light emission control circuit 206 forms a discharge loop of the anode 203 of the main capacitor, the discharge tube 205, the light emission control circuit 206, and the cathode of the main capacitor 203.

At this time, the receiver microcomputer 209 sets the terminal TRIG to High for a predetermined time to operate the trigger circuit 204 to excite the discharge tube 205 to start light emission. When the integral value of the light emission amount of the discharge tube 205 becomes a predetermined value or more, the output of the light emission amount monitor unit 218 and the output of the D / A converter 214 are in a relationship of the output of the light emission amount monitor unit 218 ≧ the output of the D / A converter 214. Become. Therefore, the output of the comparator 216 becomes Low. As a result, the output of the AND gate 217 also becomes Low (timing T2 in FIG. 15), and the light emission control circuit 206 has the anode 203 of the main capacitor, the discharge tube 205, the light emission control circuit 206, and the discharge loop of the cathode of the main capacitor 203. Shut off. Thereby, the light emission in the discharge tube 205 is stopped, and the process proceeds to step S417 in FIG.

  In step S417, 0 is set to the received data FD1 to FD4. Then, in the next step S418, 0 is set in the light emission permission flag, the next optical communication interrupt is operated at the start of communication, and the interrupt processing is ended.

  Next, timer interrupt processing for determining 0 and 1 after the start bit in the optical communication from the transmitter will be described with reference to the flowchart of FIG. The generation timing of the timer interrupt is the rise of (m) in FIG.

  First, in step S501, it is determined whether the output of the optical communication light receiving unit 220 is 1. If it is 1, the process proceeds to step S503, the carry flag C is set to 1, and the process proceeds to step S504. If the output of the optical communication light receiving unit 220 is 0, the process proceeds to step S502, the carry flag C is set to 0, and the process proceeds to step S504. In step S504, the reception buffer is shifted to the left. At this time, the carry flag C is set to the lower-order bit of the reception buffer.

  In the next step S505, it is checked whether the RBI is 7 in order to determine whether or not the optical communication has been completed for one byte. If RBI is not 7, the process proceeds to step S506, “RBI = RBI + 1” is performed, and the interrupt process is terminated. On the other hand, if RBI is 7, the process proceeds to step S507 and subsequent steps.

  If it is determined in step S505 that one byte of optical communication has not been completed and the process proceeds to step S507, it is determined whether or not the variable RI indicating the byte number of the optical communication data is zero. If the result is 0, the process proceeds to step S508, and the contents of the reception buffer are set to RD0. Then, in the next step S509, based on the received data RD0, it is determined how many bytes this communication is based on the data in FIG. 16, RIMAX is set according to the maximum number of bytes, and the process proceeds to step S517. If it is determined in step S507 that the variable RI is not 0, the process proceeds to step S510.

  In steps S510 to S516, the contents of the reception buffer are set from RD1 to RD4 based on the variable RI indicating the number of bytes of the optical communication data transmitted from the transmitter. Then, the process proceeds to step S517.

  In step S517, it is determined whether or not RI ≧ RIMAX in order to determine whether the optical communication is completed. As a result, if RI ≧ RIMAX (end of optical communication), the process proceeds to step S518, and if RI <RIMAX (during communication), the process proceeds to step S522.

  When RI ≧ RIMAX (optical communication end) and the process proceeds to step S518, RI is set to 0. Then, in the next step S519, in order to prepare for receiving the light pulse of the receiver light emission start signal transmitted by the transmitter, the light emission permission flag is set to 1, and the process proceeds to step S520. If it is determined in step S157 that RI <RIMAX (communication is in progress) and the process proceeds to step S522, “RI = RI + 1” is performed to prepare for communication, and the process proceeds to step S520. In step S520, the timer interrupt is prohibited to enable the optical pulse reception interrupt. Then, in the next step S521, the optical pulse reception interrupt is permitted and the timer interrupt process is ended.

  By performing the above optical communication pulse reception interrupt processing and timer interrupt processing, optical communication by optical communication pulses sent from the transmitter is enabled, and one or a plurality of receivers communicate the light emission amount set by the transmitter with optical communication. Can be received. It is also possible to synchronize the light emission start of each receiver upon receiving the light emission start signal.

  In this embodiment, a case has been described in which bit 7 (most significant bit) of communication data having an 8-bit configuration is used as a start bit. However, the communication data may have an 8-bit configuration including a start bit and a data portion. Alternatively, a format to which channel bits and stop bits for preventing interference are added may be used. Further, the communication order of data may be changed from bit 0 to bit 7. Further, in the first embodiment, an example in which the maximum number of receivers (maximum number of light-emitting lamps) is four is shown, but it may be more or less than this number.

  Next, a second embodiment of the present invention will be described. In the second embodiment, one of the changes from the first embodiment is that information on the subject distance detected by the distance measuring circuit 8 in FIG. 2 in step S7 in FIG. 5 is obtained in step S11 in FIG. It is included in the information transmitted to the transmitter which is the master flash device. That is, in addition to aperture, shutter speed information, and film sensitivity information, it also includes subject distance information.

  Another change is that in step S104 of FIG. 7, when the camera data is confirmed and the subject distance is closer than the set value, the communication pulse of the output of the D / A converter 114 in the transmitter of FIG. It is a point to change so that the light emission amount of a fire pulse may be lowered. Other operations and the circuit configurations of the transmitter, camera, and receiver are the same as those in the first embodiment.

  FIG. 14 shows a timing chart when the front light emission is OFF in the second embodiment. The transmitter transmits data relating to light emission (here, “10000010”). Thereafter, the transmitter does not emit light, but transmits a synchronization signal (fire pulse) to emit only the light emitted from the receiver. FIG. 14 is a timing chart in which this fire pulse is operated, and is set to perform only slave light emission at the time of photographing. The transmitter microcomputer 109 sets the output of the D / A converter 114 in accordance with the subject distance from the camera. Thereby, the light emission intensity of the optical communication pulse itself is changed (the light emission amount of the communication pulse and the fire pulse is lowered). For example, the output of the D / A converter 114 is determined by setting a level corresponding to a predetermined subject distance as indicated by L4 in FIG. At this time, even when the subject is at a short distance, the amount of light emitted does not become larger than the amount of light adjusted by the fire pulse, which is a minute amount of light, and overexposure shooting is not caused.

  According to the second embodiment described above, since the light amount of the wireless communication signal is reduced when the short distance or the ISO sensitivity is high, overexposed shooting can be prevented. It goes without saying that the same applies not only to a short distance or high ISO sensitivity but also to a short distance and high ISO sensitivity.

  In both Example 1 and Example 2, the amount of communication light emitted from the transmitter when front light emission is ON is not affected as long as the light emission amount of the fire pulse. However, if the minimum fire pulse light emission amount is determined (for example, if the communication light emission amount is set as the lower limit), the communication light emission amount may be reduced under the same conditions as when front light emission is OFF.

  Next, Embodiment 3 of the present invention will be described. The third embodiment is different from the first embodiment in that when the receiver emits the main light, the main light emission, which is a light emission for photographing, is performed after a predetermined time from the reception of the fire pulse as the light emission synchronization signal. Is a point.

  FIG. 19 shows the timing. A difference from FIG. 15 is that the light emission operation is not performed until the time T1 ″ is reached after receiving the fire pulse at T1 ′. The shooting operation is performed after a set time after the pulse emission, that is, the fire pulse is transmitted a predetermined time earlier than the shooting timing, and the receiver also emits light at the shooting operation timing after the preset time. .

  According to the third embodiment described above, the light emission operation is not performed until a preset time elapses after the receiver receives the fire pulse. Therefore, overexposed shooting can be prevented. Note that not only the first embodiment but also the second and third embodiments can be applied to a camera using an electronic image sensor (CCD, CMOS) instead of a film. In this case, sensitivity information indicating the gain of the output signal of the electronic image sensor is used instead of film sensitivity (ISO) as camera information indicating the recording medium sensitivity.

  The description of the operations of the first to third embodiments of the present invention has been completed. Finally, the effect of each embodiment in the flash photographing system that controls the light emission of the receiver by using the light emission of the transmitter as optical communication. These are listed below.

  1) The amount of light emission for optical communication is controlled from the flash light emitting unit in accordance with the recording medium sensitivity from the camera or set by the setting member 110. Specifically, when the recording medium sensitivity is higher (or higher) than a predetermined recording medium sensitivity, the light emission amount of the flash light emitting unit is decreased. Therefore, it is possible to prevent overexposure by the transmitter at the time of wireless multi-flash photography and provide an image with proper exposure.

  2) The light emission amount for optical communication is controlled from the flash light emitting unit in accordance with the subject distance from the camera or set by the setting member 110. Specifically, when the subject distance is closer (or closer) to a predetermined subject distance, the light emission amount of the flash light emitting unit is reduced. Therefore, it is possible to prevent overexposure by the transmitter at the time of wireless multi-flash photography and provide an image with proper exposure.

  3) The flash emission unit controls the light emission amount for optical communication according to the recording medium sensitivity and subject distance set from the camera or set by the setting member 110. Specifically, when the recording medium sensitivity and the subject distance are higher and closer than predetermined values, the light emission amount of the flash light emitting unit is decreased. Therefore, it is possible to prevent overexposure by the transmitter at the time of wireless multi-flash photography and provide an image with proper exposure.

  4) The transmitter can set either the first mode in which both optical communication and light emission for photographing are performed or the second mode in which only optical communication is performed. When the second mode is set, the flash emission unit controls the light emission amount for optical communication in accordance with the recording medium sensitivity set from the camera or set by the setting member 110. Therefore, it is possible to prevent overexposure by the transmitter at the time of wireless multi-flash photography and provide an image with proper exposure.

  5) The transmitter can set either the first mode in which both optical communication and light emission for photographing are performed or the second mode in which only optical communication is performed. When the second mode is set, the light emission amount for optical communication is controlled from the flash light emitting unit in accordance with the subject distance from the camera or set by the setting member 110. Therefore, it is possible to prevent overexposure by the transmitter at the time of wireless multi-flash photography and provide an image with proper exposure.

  6) The transmitter can set either the first mode in which both optical communication and light emission for photographing are performed or the second mode in which only optical communication is performed. When the second mode is set, the flash emission unit controls the light emission amount for optical communication according to the recording medium sensitivity and the subject distance set from the camera or set by the setting member 110. ing. Therefore, it is possible to prevent overexposure by the transmitter at the time of wireless multi-flash photography and provide an image with proper exposure.

  7) The transmitter can set either the first mode in which both optical information communication and light emission for photographing are performed or the second mode in which optical information communication is performed. When the second mode is set, the transmitter transmits a fire pulse earlier than the emission timing of the slave flash device by a predetermined time, and the receiver provided in the slave flash device transmits the fire pulse. Is received, the slave flash device is caused to emit light after the predetermined time. Therefore, it is possible to prevent overexposure and obtain a properly exposed image.

1 is a block diagram showing a circuit configuration of a transmitter (master flash device) according to Embodiment 1 of the present invention. FIG. It is a block diagram which shows the circuit structure of the camera concerning Example 1 of this invention. It is a block diagram which shows the circuit structure of the receiver (slave flash device) concerning Example 1 of this invention. FIG. 4 is a circuit diagram showing a specific configuration of an optical communication receiving unit provided in the receiver of FIG. 3. 3 is a flowchart showing a part of the operation of the camera of FIG. 2. 6 is a flowchart showing a continuation of the operation of FIG. It is a flowchart which shows operation | movement of the transmitting apparatus of FIG. It is a flowchart which shows the detail of the operation | movement performed in step S112 of FIG. It is a flowchart which shows the operation | movement of 1 byte optical communication in the transmitter of FIG. It is a flowchart which shows the operation | movement with the receiver of FIG. 4 is a flowchart illustrating an operation of optical communication in the receiver of FIG. 3. FIG. 4 is a timing chart of each unit during 1-byte communication of the transmitter of FIG. 1 and the receiver of FIG. 3 when front light emission is ON. It is a timing chart of each part at the time of 1 byte communication of the transmitter at the time of the conventional front light emission OFF, and a receiver. It is a timing chart which shows the waveform of each part at the time of 1 byte communication with the transmitter and receiver at the time of front light emission OFF in Example 2 of this invention. FIG. 4 is a timing chart showing waveforms of respective parts from receiving communication to light emission in the receiver of FIG. 3. It is the figure which showed an example of the slave number data of the flowchart description of the present Examples 1-3. It is the figure which showed an example of the film sensitivity data of the flowchart description of the present Examples 1-3. It is the figure which showed an example of the light emission amount data of the flowchart description of the present Examples 1-3. It is the timing chart which showed the waveform of each part from receiving communication with the receiver in Example 3 of this invention to light emission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Camera microcomputer 4 Setting member 8 Ranging circuit 9 Focal length detection circuit 103,203 Main capacitor 105,205 Discharge tube 106,206 Light emission control circuit 109 Transmitter microcomputer 110 Setting member 209 Receiver microcomputer 114,214 D / A converter 116 , 216 Comparator 117 AND gate 118, 218 Light emission amount monitor unit

Claims (6)

A flash device that performs a light emission instruction to another flash device by optical communication,
A light emitting means for performing optical communication with the other flash device by emitting light;
A light emission control means for controlling a light emission amount of the light emitting means when performing optical communication based on at least one of a subject distance and a photographing sensitivity of a mounted camera when the light emitting means is not caused to emit light for irradiating the subject. and, the possess,
When the shooting sensitivity is a second shooting sensitivity higher than the first shooting sensitivity, or when the subject distance is a second distance closer than the first distance, the light emission control unit A flash device characterized by lowering the light emission amount of the light emitting means when performing optical communication than when sensitivity and the subject distance do not satisfy any of the conditions .   When the photographing sensitivity is higher than a predetermined sensitivity, or when the subject distance is closer than a predetermined subject distance, the light emission control unit satisfies both the conditions for the photographing sensitivity and the subject distance. The flash device according to claim 1, wherein the light emission amount of the light emitting means when performing optical communication is lower than when there is no optical communication.   2. The flash device according to claim 1, wherein the light emission control unit decreases the light emission amount of the light emission unit when performing optical communication as the photographing sensitivity is higher or the subject distance is closer.   One of a first mode in which the light emitting unit performs both light emission for optical communication and light emission for irradiating a subject, and a second mode in which the light emitting unit performs only light emission for optical communication are set. The light emission amount of the light emitting means when performing optical communication by the light emission control means is controlled when the second mode is set. The flash device according to Item 1. A camera for instructing the flash device to emit light by optical communication,
A light emitting means for performing optical communication with the flash device by emitting light;
A light emission control means for controlling a light emission amount of the light emission means when performing optical communication based on at least one of a subject distance and a photographing sensitivity of the camera when the light emission means is not caused to emit light to irradiate the subject ; I have a,
When the shooting sensitivity is a second shooting sensitivity higher than the first shooting sensitivity, or when the subject distance is a second distance closer than the first distance, the light emission control unit A camera characterized in that the light emission amount of the light emitting means when performing optical communication is lower than when sensitivity and the subject distance do not satisfy any of the conditions . A flash photographing system having a camera and a flash device, and performing a light emission instruction from the camera to the flash device by optical communication,
A light emitting means for performing optical communication with the flash device by emitting light;
A light emission control means for controlling a light emission amount of the light emission means when performing optical communication based on at least one of a subject distance and a photographing sensitivity of the camera when the light emission means is not caused to emit light to irradiate the subject ; I have a,
When the shooting sensitivity is a second shooting sensitivity higher than the first shooting sensitivity, or when the subject distance is a second distance closer than the first distance, the light emission control unit A flash photographing system characterized by lowering the light emission amount of the light emitting means when performing optical communication than when sensitivity and the subject distance do not satisfy any of the conditions .

Images