JP4300750B2 - Flash device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flash device that illuminates a subject in synchronization with camera shooting.
[0002]
[Prior art]
Conventionally, a flash device that performs dimming control is known. In this light control, the reflected light returning from the subject after the start of light emission is measured, and the light emission stop control is performed when the photometric integrated value reaches the target light amount.
Normally, in such dimming control, a certain amount of overrun period is required from the time point when the light emission is stopped until the light emission is actually stopped. For this reason, the light increase during the overrun period (overrun light amount) has occurred as a dimming error.
Such a light control error has a larger effect as a minute light emission such as short-distance illumination, and thus has been a cause of limiting the near side of the illumination distance of the flash device.
[0003]
[Problems to be solved by the invention]
Several correction techniques have been disclosed in order to correct the overrun light amount that is the cause of such dimming errors. Hereinafter, these correction techniques and their problems will be described.
[0004]
[A] Correction technology in which an appropriate fixed value is subtracted from the target light amount in advance By subtracting an appropriate fixed value in advance from the target light amount, the control time point for stopping the light emission can be advanced. This correction technique is excellent particularly in that the light control error generated at a short distance is reduced and the light control errors at a short distance and a long distance are averaged. As a result, the near side of the illumination distance can be easily shortened.
However, since this correction technique uses a fixed value, it is difficult to correct the dimming error with higher accuracy.
[0005]
[B] Correction technology for correcting the target light amount over time The ratio between the target light amount and the overrun light amount changes every moment depending on the timing of light emission stop. Accordingly, by dynamically changing the value of the target light amount as time passes after the start of light emission, it is possible to perform dimming control that allows for a change in the ratio of the overrun light amount. (That is, since the ratio of the overrun light amount is large at the beginning of light emission, the correction amount is increased to lower the target light amount. As the time elapses, the overrun light amount ratio becomes smaller. To be smaller.)
However, in such a correction technique, the target light amount must be rewritten as needed in parallel with the photometry / comparison operation. Therefore, the timing of the rewriting operation is difficult, and there is a problem that the output operation of the light emission stop signal becomes unstable before and after the rewriting process. Therefore, it is necessary to take complicated measures such as canceling the light emission stop signal that is output in error or reliably outputting an accurate light emission stop signal.
[0006]
[C] Correction Technology Based on Increasing Rate of Reflected Light Amount This correction technology is disclosed in Japanese Patent Application Laid-Open No. 57-118231. In this correction technique, immediately after the start of light emission, the rate of increase in the reflected light returning from the subject (the tilt angle of the photometric output) is measured, and the subject distance is estimated from this tilt angle. By using this subject distance, it is possible to determine the timing of stopping the light emission.
However, with this technique, it is necessary to determine the rate of increase in reflected light immediately after the start of light emission, and it may be difficult to perform high-precision correction, such as being easily affected by surrounding high-frequency noise.
[0007]
[D] Correction Technique Using Preliminary Light As shown in FIG. 6, there is known a flash device that performs preliminary light emission before the start of exposure of a camera. By measuring the amount of light reflected from the subject in this preliminary light emission, the amount of reflected light reflecting the state of the object scene (the reflectance of the subject, the subject distance, etc.) can be obtained. If the amount of reflected light is known, since the light emission waveform (full light emission waveform, etc.) of the flash device is known, the reflected waveform (temporal change in the amount of reflected light) during main light emission can be predicted in advance. Based on the reflection waveform predicted in this way, it is possible to determine before the main light emission whether the target light amount can be obtained by stopping the main light emission. Such a determination can take into account the increase in the amount of overrun light, so that a very accurate light adjustment error can be corrected.
However, in order to carry out such preliminary light emission, it is essential for the camera to cope with it. That is, as shown in FIG. 6, the camera side must separately output a start signal for preliminary light emission before the start of exposure. For this reason, there is a problem in that preliminary light emission cannot be performed except for a new camera.
The preliminary light emission is performed before the exposure of the camera is started. Therefore, the preliminary light emission itself does not substantially contribute to subject illumination. Therefore, there is a problem that the GN (guide number) is substantially reduced by the amount of power consumed for the preliminary light emission, and the farthest distance that can be illuminated is shortened.
In addition, the battery consumption of the flash device increases by the power consumption of the preliminary light emission. For this reason, there is a problem that the usable time of the battery (that is, the number of times that light can be emitted) decreases.
From the viewpoint of such power consumption, it is preferable to suppress the preliminary light emission to the smallest possible light emission amount. However, in the case of minute preliminary light emission, a photometric error in the amount of reflected light increases, and a new problem arises that it is difficult to increase the accuracy of light control.
In addition, this preliminary light emission has to be executed before the start of exposure, causing a problem that the release time lag becomes slightly longer.
[0008]
In view of the above-described problems, an object of the present invention is to propose a new dimming method with high dimming accuracy.
[0009]
[Means for Solving the Problems]
The present invention will be described below.
A flash device according to the present invention is a flash device that illuminates an object scene of a camera in synchronization with a light emission start signal, a photometric sensor for monitoring dimming control of the flash device, and a light emission start signal. Synchronously, after the start of exposure of the camera, an initial light emitting unit that performs initial light emission, and photometry of the photometric sensor is started in synchronization with the light emission start signal, and the initial light emission stop control is performed. Control means for ending the photometry after waiting for a predetermined time exceeding the overrun period of the initial light emission from the time point, thereby obtaining a first photometric integrated value of the photometric sensor in the initial light emission, and the control means An arithmetic unit for setting a target value of additional light emission necessary to reach the final target of the light control based on the obtained first photometric integrated value, and exposure after the initial light emission and the initial light emission Add emitting carried out during, at the time when the second photometric integrated value of the light sensing detector in the additional emission reaches the target value, and a additional light emitting unit for performing stop control of the additional emission.
The photometric sensor includes a photometric sensor A that measures light from the object scene, and a photometric sensor M that measures light emitted from the flash device, and the calculation unit converts the initial light emission into the photometric sensor A. And the photometric sensor M, and an additional target necessary for the photometric result of the photometric sensor A to reach the final target is obtained in terms of the output of the photometric sensor M. Further, additional light emission may be performed during the exposure period of the camera, and the photometry result of the photometric sensor M may be monitored based on the additional target to determine the stop control timing of the additional light emission.
The light emission start signal may be an X contact of the camera, and the initial light emission unit may start the initial light emission triggered by the X contact of the camera.
Further, the additional light emitting unit may determine whether or not the additional target is a value incapable of dimming control, and when the dimming control is not possible, the additional light emission may be omitted.
In addition, the photometric sensor includes a light receiving unit that converts light into a photometric output, a storage unit that accumulates the photometric output of the light receiving unit, and a fixed discharge amount from the storage unit, and a storage amount of the storage unit. May be provided, and a counting unit that counts the number of discharges of the discharging unit to obtain a photometric integrated value.
The discharge unit may lower the discharge amount at the initial light emission than the discharge amount at the additional light emission.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the flash device 11 in the present embodiment.
As shown in FIG. 1, the flash device 11 is roughly configured from the following configuration requirements.
[0011]
(1) Arc tube Xe for flash emission
(2) Photometric sensor A that measures light from the object scene
(3) Photometric sensor M for measuring light emitted from the arc tube Xe
(4) Selector 13 for switching and outputting the photometric integrated value of photometric sensor A and the photometric integrated value of photometric sensor M
(5) Digital comparator 14 that compares the selector output with a threshold value
(6) One-shot timer 15 for shaping the waveform of the comparator output
(7) Light emission control circuit 16 for performing light emission control of the arc tube Xe
(8) Microprocessor 17 for system controlling the flash device 11
(9) Leg contact 18 for exchanging signals with the camera side
(10) Memory 19
[0012]
Among these, the photometric sensor A is composed of the digital photometric circuit shown in FIG. Hereinafter, the circuit configuration of the digital photometry circuit will be described.
First, in the photometric sensor A, a photodiode PDa is provided at a position for receiving light from the object scene. The cathode of the photodiode PDa is connected to the power supply line Vcc. On the other hand, the anode of the photodiode PDa is connected to one terminal of the anti-latching resistor Rpd, one terminal of the capacitor Cpd, the positive input terminal of the comparator CMP, and the constant current source CS.
[0013]
The other terminal of the resistor Rpd is connected to the power supply line Vcc. The other terminal of the capacitor Cpd is connected to the ground line GND.
A voltage Vth is supplied to the negative input terminal of the comparator CMP through a constant voltage circuit. The output of the comparator CMP is given to the input terminal D of the D type flip-flop FF1.
[0014]
The output Q of the flip-flop FF1 is given to one input terminal of the NAND circuit N1. The sample clock CK is supplied to the clock terminal of the flip-flop FF1. Further, an inverted signal of the sample clock CK is given to the other input terminal of the NAND circuit N1.
The output CTL of the NAND circuit N1 is supplied to the control input of the constant current source CS and the clock terminal of the counter 12A. A reset signal is given from the microprocessor 17 to the reset terminal CLR of the counter 12A.
[0015]
The operation of this digital photometry circuit will be briefly described below.
A photocurrent is generated in the photodiode PDa in accordance with the amount of received light. This photocurrent is accumulated in the capacitor Cpd and raises the voltage of the capacitor Cpd. When this voltage rise exceeds the voltage Vth, the comparator output of the comparator CMP is inverted. Along with the output inversion, the NAND circuit N1 outputs an output CTL having a certain time width. The constant current source CS discharges a constant current amount (charge amount) from the capacitor Cpd for each pulse of the output CTL. By such a feedback operation, the voltage of the capacitor Cpd is kept near the voltage Vth. At this time, the pulse count value of the output CTL by the counter 12A is a digitized value of the photometric integrated value of the light returning from the object scene.
[0016]
The photometric sensor M also has the same circuit format as the photometric sensor A described above except that the photodiode PDm is provided at a position where the light emission of the arc tube Xe is received. (However, the signal constant in the circuit is optimized by changing the circuit constant by an amount different from the photometric sensor A.)
In this case, the pulse count value of the counter 12M on the photometric sensor M side indicates a value obtained by digitizing the photometric integrated value of the light from the arc tube Xe.
[0018]
[Description of operation of this embodiment]
2 and 3 are flowcharts for explaining dimming control of the flash device 11.
FIG. 4 is a timing chart showing the dimming operation of the flash device 11.
Hereinafter, the dimming operation of the flash device 11 will be described with reference to FIGS.
[0019]
Step S1: First, the microprocessor 17 resets the count values of the counters 12A and 12M and maintains this reset state. In this state, the microprocessor 17 sets the selector 13 to the photometric sensor M side.
[0020]
Step S2: The boosted voltage for light emission is accumulated in the light emission control circuit 16.
[0021]
Step S3: The microprocessor 17 sets the discharge current on the photometric sensor M side to a small value S for initial light emission. Further, the microprocessor 17 sets the threshold value Q1 for initial light emission in the digital comparator 14. The threshold value Q1 may be a value that is insufficient for the final target of dimming control. If the final target cannot be determined at this time, the threshold value Q1 may be set so as to be insufficient for the “expected value of the final target” that is empirically or roughly predicted.
[0022]
Step S4: On the camera side, according to the shutter release, the shutter is opened (front curtain travel), and exposure is started.
[0023]
Step S5: As shown in FIG. 4, when the shutter is fully opened, a light emission start signal (for example, an X contact) is output from the camera side. This light emission start signal is given to the microprocessor 17 via the leg contact 18.
[0024]
Step S6: With this light emission start signal, the microprocessor 17 releases the reset state of the counters 12A and 12M and starts counting.
[0025]
Step S7: Furthermore, the microprocessor 17 gives this light emission start signal to the light emission control circuit 16. The light emission control circuit 16 causes the arc tube Xe to start initial light emission in response to the light emission start signal.
[0026]
Step S8: The photometric sensor M directly receives a part of this initial light emission. At this time, the photometric integrated value of the initial light emission is output from the counter 12M. The photometric integrated value of the initial light emission is given to the digital comparator 14 via the selector 13. The digital comparator 14 inverts the comparator output when the photometric integrated value of the initial light emission reaches the threshold value Q1. The inversion of the comparator output is shaped into a pulse signal via the one-shot timer 15 and is given to the light emission control circuit 16 as a light emission stop signal.
The light emission control circuit 16 cuts off the current supply of initial light emission in accordance with the light emission stop signal.
[0027]
Step S9: The microprocessor 17 waits for the stop of the initial light emission by waiting for a predetermined time from the stop control time of the initial light emission. The predetermined time may be a time that exceeds the overrun period of the initial light emission, and is set to about 100 μsec, for example.
[0028]
Step S10: The microprocessor 17 acquires information on the photometric integrated value Q2 of the photometric sensor M after the light emission is stopped.
[0029]
Step S11: The microprocessor 17 acquires information on the photometric integrated value P2 of the photometric sensor A after the light emission is stopped.
[0030]
Step S12: The microprocessor 17 calculates the additional target K based on the following equation.
K = (P × Q2 / P2-Q2) × S / L
However, P is a value representing the final target of the light control by the output conversion of the photometric sensor A. S is a discharge current value at the time of initial light emission. L is a discharge current value at the time of additional light emission. K is a value representing the additional target in terms of output of the photometric sensor M.
When the discharge current is not switched and the counter 12M is not reset after the initial light emission, the microprocessor 17 may calculate the additional target K based on the following equation.
K = P × Q2 / P2
[0031]
Step S13: The microprocessor 17 corrects the additional target K by the amount of overrun light based on the photometry result of the initial light emission, and obtains the additional target K ′. It should be noted that all the same techniques as the conventional correction technique using preliminary light emission can be adopted as the correction technique here.
Incidentally, the initial light emission is also effectively used as subject illumination during shooting. Therefore, the waste of power consumption is small, and the initial light emission can be set to about half the final target. In this case, as shown in FIG. 5, the light emission waveform of the initial light emission and the light emission waveform of the additional light emission are roughly similar. As a result, it is possible to easily predict the overrun light amount of the additional light emission from the overrun light amount of the initial light emission. In such a case, the additional target K can be corrected to K ′ by a simple calculation such as the following equation.
K ′ = K × Q1 / Q2
[0032]
Step S14: The microprocessor 17 determines whether or not the additional target K ′ is less than the predetermined value Z. The predetermined value Z is a lower limit value of an additional target that can be dimmed.
Here, when the additional target K ′ is less than the predetermined value Z, it is determined that the dimming control cannot be performed within the allowable accuracy range, and the additional light emission after step S15 is omitted.
On the other hand, when the additional target K ′ is equal to or greater than the predetermined value Z, it is determined that the dimming control is possible within the allowable accuracy range, and additional light emission from step S15 is executed.
[0033]
Step S15: The microprocessor 17 resets the count value of the counter 12M and maintains this reset state.
[0034]
Step S16: The microprocessor 17 sets an additional target K ′ for additional light emission in the digital comparator 14. Further, the microprocessor 17 changes the discharge current on the photometric sensor M side to a large value L for additional light emission.
[0035]
Step S17: The microprocessor 17 cancels the reset state of the counter 12M and starts counting.
[0036]
Step S18: At the same time when the counter 12M starts counting, the microprocessor 17 gives an additional light emission start signal to the light emission control circuit 16 to cause the light emission tube Xe to start additional light emission.
[0037]
Step S19: The photometric sensor M directly measures a part of the additional light emission. At this time, the counter 12M outputs a photometric integrated value of additional light emission. The photometric integrated value of this additional light emission is given to the digital comparator 14 via the selector 13. The digital comparator 14 inverts the comparator output when the photometric integrated value of this additional light emission reaches the threshold value K ′. The inversion of the comparator output is shaped into a pulse signal via the one-shot timer 15 and is given to the light emission control circuit 16 as a light emission stop signal.
The light emission control circuit 16 cuts off the additional light emission current supply in accordance with the light emission stop signal.
[0038]
Step S20: On the camera side, after stopping the additional light emission, the shutter is closed and the exposure operation is completed. The microprocessor 17 returns the operation to step S1 in preparation for the next shooting.
The dimming control of the flash device 11 is completed by the series of operations described above.
[0039]
[Effects of this embodiment, etc.]
In the present embodiment, initial light emission and additional light emission are performed stepwise after the start of exposure. Based on the photometry result of the initial light emission, it is possible to perform dimming control with high accuracy in consideration of the reflectance of the object field, the subject distance, and the overrun light quantity.
[0040]
Furthermore, in this embodiment, since the initial light emission can be effectively used for illumination at the time of shooting, even if the initial light emission is increased, power consumption is not wasted. Therefore, by increasing the initial light emission, it is possible to easily increase the photometric accuracy of the initial light emission.
[0041]
Further, in the present embodiment, unlike the conventional method using preliminary light emission, no timing signal before the start of exposure is required. Therefore, the flash device 11 of this embodiment can be used for a general camera that outputs only the X contact.
[0042]
Furthermore, in this embodiment, since the initial light emission can be effectively used for illumination at the time of photographing, a substantial decrease in GN (guide number) does not occur so much. Therefore, it is easier to lengthen the farthest distance that the flash device can be illuminated than in the conventional method using preliminary light emission.
[0043]
Further, in the present embodiment, the battery consumption of the flash device can be reduced as much as unnecessary power consumption such as preliminary light emission does not occur. As a result, the usable time of the battery (that is, the number of times that light can be emitted) can be increased as compared with the preliminary light emission method.
[0044]
Also, the release time lag can be shortened by the amount that preliminary light emission is not performed before the start of exposure.
[0045]
Furthermore, in this embodiment, the photometric integration value of the photometric sensor M is monitored to determine the light emission stop timing. Since the photometric sensor M is not significantly affected by the object field, the photometric integrated value is output more stably and more accurately than the photometric sensor A. Therefore, by monitoring the photometric integrated value of the photometric sensor M, the light control amount of the flash device 11 can be controlled with higher accuracy.
[0046]
In the present embodiment, when the target value K ′ for additional light emission is less than the predetermined value Z, the additional light emission is omitted. Therefore, it is possible to eliminate the possibility that the exposure amount may exceed by a plurality of times of initial light emission / additional light emission.
[0047]
In this embodiment, the digital photometric circuit shown in FIG. 1 is used as the photometric sensor A and the photometric sensor M. This digital photometric circuit is excellent in that the photometric integrated value can be digitized in real time without delay, and is a circuit format particularly suitable for the dimming method of the present embodiment.
[0048]
Furthermore, in the present embodiment, the discharge current value S at the time of initial light emission is lower than the discharge current value L at the time of additional light emission. As a result, the photometric accuracy of the initial light emission can be further increased, and the additional target K ′ can be determined more accurately.
[0049]
[Supplementary items of the embodiment]
In the present embodiment, the timing of the initial light emission stop control is determined based on the photometric result of the photometric sensor M. In this case, there is an excellent advantage that the initial light emission can be stably performed regardless of the situation of the object scene (reflectance and subject distance). However, the present invention is not limited to this. Generally, the initial light emission is not limited as long as the light emission amount is insufficient for the final target of the dimming control.
[0050]
For example, the timing of the stop control of the initial light emission may be determined based on the photometric result of the photometric sensor A. In this case, it is possible to prevent a situation in which the final target should be exceeded in the initial light emission stage.
[0051]
Further, for example, the stop control of the initial light emission may be performed after a certain period of time using a timer. In this case, there is an effect that the timing determination of the stop control of the initial light emission can be simplified.
[0052]
In the present embodiment, the flash device 11 separate from the camera has been described. However, the present invention is not limited to this. Of course, the present invention may be applied to a flash device with a built-in camera.
[0053]
In the present embodiment, the case where the light emission start signal is output from the camera side has been described. However, the present invention is not limited to this. For example, in a flash device of a slave light emission method, light emission or a light emission stop of other flash devices may be detected and used as a light emission start signal.
[0054]
Further, in the present embodiment, the external light control flash device 11 has been described. However, the present invention is not limited to this. For example, as the photometric sensor A, a photometric sensor for TTL light control built in the camera can be used.
[0055]
Further, in the present embodiment, the case where the initial light emission and the additional light emission are performed by single emission has been described. However, the present invention is not limited to this. For example, one or both of the initial light emission and the additional light emission may be performed by FP light emission.
[0056]
In the present embodiment, a camera using a focal plane shutter has been described. However, the shutter of the camera is not limited to the focal plane shutter. For example, a lens shutter or an electronic shutter may of course be used.
[0057]
Further, in the present embodiment, initial light emission is started with the focal plane shutter fully opened. Therefore, the reflected light of the initial light emission uniformly hits the entire exposure surface, and it becomes possible to prevent the exposure unevenness of the initial light emission. However, the present invention is not limited to this.
[0058]
For example, in the case of a lens shutter, some electronic shutters, and FP light emission, there is no risk of exposure unevenness of initial light emission, and therefore, initial light emission may be started without waiting for the fully opened state as described above. In this case, it is also possible to start the initial light emission before the start of exposure and stop the initial light emission after the exposure starts. Such an operation provides an excellent advantage that a high-speed shutter can be used on the camera side, instead of using 100% of the initial light emission for subject illumination.
[0059]
Further, the flash device 11 of the present embodiment may be mounted on a hot shoe of a camera or may be disposed away from the camera. When the camera and the flash device are separated from each other, it is preferable to exchange control information such as a light emission start signal by using a sync cord, infrared rays, radio waves, or the like.
[0060]
The flash device 11 of this embodiment can be used for either a silver salt camera or an electronic camera.
[0061]
【The invention's effect】
In the present invention, the initial light emission and the additional light emission are performed in stages after the start of exposure of the camera. By using the photometric information at the time of initial light emission, it is possible to appropriately correct the light control error.
[0062]
Further, in the present invention, initial light emission is performed after the start of exposure. Therefore, unlike conventional preliminary light emission (light emission performed before the start of exposure), the present invention does not necessarily require a light emission start signal before the start of exposure. Therefore, a flash device capable of performing advanced dimming control is realized even in a general camera (however, this description intentionally excludes that the present invention uses a light emission start signal before the start of exposure). Not a thing).
[0063]
In addition, in the present embodiment, since the initial light emission is performed after the start of exposure, the initial light emission is also effectively used as illumination light at the time of photographing. Therefore, power consumption is less than that of preliminary light emission that does not contribute to subject illumination.
[0064]
Furthermore, when preliminary light emission is not performed before the start of exposure, it becomes easy to shorten the release time lag of the camera.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a flash device 11 in the present embodiment.
FIG. 2 is a flowchart (first half) for explaining dimming control of the flash device 11.
FIG. 3 is a flowchart (second half) for explaining dimming control of the flash device 11;
4 is a timing chart showing a dimming operation of the flash device 11. FIG.
FIG. 5 is a timing chart showing a dimming operation of the flash device 11;
FIG. 6 is a timing chart showing a conventional dimming operation.
[Explanation of symbols]
A, M Photometric sensors PDa, PDm Photodiode Rpd Resistor CK Sample clock N1 NAND circuit FF1 Flip-flop CS Constant current source CMP Comparator Cpd Capacitor Xe Light emission tube 11 Flash device 12A, 12M Counter 13 Selector 14 Digital comparator 15 One shot timer 16 Light emission control Circuit 17 Microprocessor 18 Leg contacts

Claims (6)

A flash device that illuminates the camera scene in synchronization with a light emission start signal,
A photometric sensor for monitoring dimming control of the flash device;
In synchronization with the light emission start signal, an initial light emitting unit that performs initial light emission after the start of exposure of the camera;
The photometry of the photometric sensor is started in synchronization with the light emission start signal, and the photometry is performed after waiting for a predetermined time that exceeds the overrun period of the initial light emission from the time when the initial light emission stop control is performed. Control means for ending and thereby obtaining a first photometric integrated value of the photometric sensor in the initial emission;
Based on the first photometric integrated value obtained by the control means, a calculation unit for setting a target value of additional light emission necessary to reach the final target of the light control,
The initial emission after and the initial emission conducted additional emission during made exposure periods, when the second photometric integrated value of the light sensing detector in the additional emission reaches the target value, the additional emission stop control A flash device comprising: an additional light emitting unit that performs the above . The flash device according to claim 1,
As the photometric sensor, a photometric sensor A for measuring light from the object field, and a photometric sensor M for measuring light emitted from the flash device,
The arithmetic unit measures the initial light emission with the photometric sensor A and the photometric sensor M, and converts an additional target necessary for the photometric result of the photometric sensor A to reach the final target as an output of the photometric sensor M. In
The additional light emission unit performs additional light emission after the initial light emission and during the exposure period of the camera, monitors a photometric result of the photometric sensor M based on the additional target, and sets a stop control timing of the additional light emission. A flash device characterized by deciding. The flash device according to claim 1 or 2 ,
The light emission start signal is an X contact of the camera,
The initial light emitting unit starts the initial light emission triggered by an X contact of the camera. The flash device according to any one of claims 1 to 3 ,
The additional light emitting unit includes:
It is determined whether or not the additional target is a value incapable of dimming control, and when the dimming control is impossible, the additional light emission is omitted. The flash device according to any one of claims 1 to 4 ,
The photometric sensor is
A light receiving unit for converting light into photometric output;
An accumulator for accumulating the photometric output of the light receiving unit;
A discharge unit that discharges from the storage unit by a certain discharge amount, and keeps the storage amount of the storage unit substantially constant;
A flash unit comprising: a counting unit that counts the number of discharges of the discharge unit to obtain a photometric integrated value. The flash device according to claim 5 ,
The discharge part is
The flash device, wherein the discharge amount at the initial light emission is lower than the discharge amount at the additional light emission.

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