JPH0421851B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a flash photography system and a flash device.

Prior Art Conventionally, when taking photographs using a strobe device that can limit the maximum light output, the photographer sets a limit on the maximum light output of the strobe device, and adjusts the flash within the range of the flash output within this limit. Do light. This type of strobe device can limit the maximum flash output of the strobe so that the charging of the strobe follows the continuous shooting when flash photography is repeated at a fairly rapid rate, and it also allows for proper exposure within that range. The strobe light is adjusted so that

On the other hand, when performing flash photography by combining the above-mentioned strobe device with a camera that uses automatic aperture control, which performs programmed aperture operation that detects the surrounding light of the subject and automatically adjusts the aperture, Therefore, the aperture of the camera is determined, so in cases where the surroundings are very bright, the aperture value becomes large, and the limited amount of light emitted by the strobe is insufficient to expose the main subject. There is a high possibility that such a situation will appear conspicuously in backlit photography during the day.

Purpose The present invention has been made in view of the above-mentioned problems.The purpose of the present invention is to reduce the maximum emitted light amount of the strobe when the camera is set to the program aperture mode in an auto strobe having a function of limiting the maximum emitted light amount. It is an object of the present invention to provide a flash photographing system and a flash device that can eliminate the above-mentioned problems by removing the restrictions.

Summary of the Invention A flash photographing system of the present invention includes a flash light emitting means, a light emitting start signal outputting means for outputting a light emitting start signal in connection with a shutter operation, a light receiving means for receiving reflected light from a subject, and a light receiving means for the light receiving means. an integrating means for integrating the output of the integrating means, and a first light emission stop signal output that compares the integral value of the integrating means with a predetermined value and outputs a first light emission stop signal when the integrated value reaches the predetermined value. and a first light emitting means for allowing the flash light emitting means to emit light up to its maximum amount.
switching means for switching between a light emission mode of the flash light emitting means and a second light emission mode that limits the light emission amount of the flash light emission means to a predetermined light emission amount or less that is less than the maximum light emission amount; a second light emission stop signal output means for outputting a second light emission stop signal when the light emission amount of the light emission means reaches the predetermined light emission amount; and in response to the light emission start signal, the flash light emission means starts light emission. a light emission start means for causing the flash light emitting means to stop emitting light in response to the first or second light emission stop signal; and an automatic aperture control mode for automatically controlling the aperture according to external light. a selection means for selecting one from a plurality of aperture control modes including; and a setting means for setting the light emission mode to a first light emission mode independently of the switching means when the automatic aperture control mode is selected. It is characterized by having the following. Further, the flash device of the present invention includes a light emission start signal output means that outputs a light emission start signal in connection with the shutter operation, and a plurality of aperture control modes including an automatic aperture control mode that automatically controls the aperture according to external light. A flash device used with a camera body having selection means for selecting one mode from among modes, and output means for outputting a mode signal corresponding to the selected aperture control mode, the flash device comprising: a flash light emitting means; a light emission start signal input means for inputting a start signal; a light emission start means for starting the flash light emission means in response to the light emission start signal; and a light emission start means for causing the flash light emitting means to start emitting light in response to the light emission start signal; a first light emitting stop signal input means for inputting a light emitting stop signal of 1; and a first light emitting stop signal input means for inputting a light emitting stop signal of 1; and a first light emitting stop signal input means for inputting a light emitting stop signal;
switching means for switching between the light emission mode of the flash light emitting means and a second light emission mode that limits the light emission amount of the flash light emitting means to a predetermined light emission amount or less that is less than the maximum light emission amount; a second light emission stop signal output means for outputting a second light emission stop signal when the light emission amount of the flash light emitting means reaches the predetermined light emission amount; and a second light emission stop signal output means responsive to the first or second light emission stop signal. a light emission stopping means for stopping the light emission of the flash light emitting means; a mode signal input means for inputting the mode signal; and a first light emission mode when the automatic aperture control mode is selected, regardless of the switching means. and setting means for setting.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings.

In FIG. 1, the right half of the broken line A indicates a strobe-side circuit 1 provided in the strobe device 100, for example, as shown in FIG. The camera side circuit 2 shown in FIG.

As shown in FIG. 1, in a strobe side circuit 1 provided in a strobe device, the negative electrode of a power supply battery 1 is grounded via a power switch 2, and further,
A DC booster circuit 3, which is known per se, is connected in parallel to the series circuit of the power supply battery 1 and the power switch 2, and a main capacitor 5 is further connected in parallel to the booster circuit 3 via a diode 4. Resistor 6, capacitor 7, transformer 8, trigger SCR
The circuit consisting of 9 triggers the xenon tube 10 to start emitting light. Further, the light emission of the xenon tube 10 is controlled by the xenon tube driving SCR 11 connected in series with the xenon tube 10. resistance 1
2. Commutation capacitor 13, SCR 1 for stopping light emission
The circuit consisting of 4 is the SCR11 for driving the xenon tube.
Applying a reverse voltage to this SCR for driving the xenon tube
11 is turned off to stop the xenon tube 10 from emitting light.

A series circuit of resistors 15 and 16 is connected in parallel with the main capacitor 5, and a connection point between the resistors 15 and 16 is connected to the + input of the comparator 17. A reference voltage source 18 is connected to the negative input of this comparator 17, and the output of this comparator 17 is connected to one input of an AND gate 19. In this circuit,
The comparator 17 detects that the charging voltage of the main capacitor 5 exceeds a certain value by comparing it with the reference voltage of the reference voltage source 18, and the comparator 17 outputs a charging completion signal.

As shown in FIG. 2, the photovoltaic element 20 is fixed at a position where it can receive the light emitted from the xenon tube 10 through the notch 101a of the concave mirror 101 that reflects the light emitted from the xenon tube 10 in the strobe device 100.

As shown in FIG. 1, the cathode of this photovoltaic element 20 is connected to a constant voltage source (not shown), and the anode of this photovoltaic element 20 is connected to an integrating capacitor 21. The collector of a transistor 22 is connected to the connection point between the photovoltaic element 20 and the integrating capacitor 21, the emitter of this transistor 22 is grounded, and connected to the output of an inverter 24 via a base resistor 23. Integrating capacitor 21
Further, a switch 25 for limiting the maximum amount of light emitted from the parallel xenon tubes 10 is connected. Further, the connection point between the anode of the photovoltaic element 20 and the integrating capacitor 21 is connected to the + input of the comparator 26, and the positive electrode of the reference voltage source 27 is connected to the - input of the comparator 26. The negative pole of is grounded. The output of comparator 26 is connected to one input of AND gate 28. The above-described photovoltaic element 20, integrating capacitor 21, comparator 26, and reference voltage source 27 constitute a maximum light emission amount limiting circuit of the strobe. In this circuit, when a photocurrent flows through the photovoltaic element 20 due to light emission from the xenon tube 10,
When the transistor 22 is off and the switch 25 is open, the integrating capacitor 21 is charged, and when this charging voltage becomes greater than the voltage of the reference voltage source 27, the output of the comparator 26 is inverted to a high level.

A switch 30 that is closed when the restriction on the amount of emitted light is released using the resistor 29 and the manual of the strobe device.
A series circuit of is connected between a constant voltage source (not shown) and ground, and a connection point between resistor 29 and switch 30 is connected to one input of OR gate 31.

A switch 32 that closes in synchronization with the full opening of the shutter curtain is provided in the camera-side circuit 2, and this switch 32 is connected to the connection terminal _J2 , which in turn connects to the one-shot circuit ₃ of the strobe-side circuit 1.
Connected to input 3. Further, the input of this one-shot circuit 33 is connected via a resistor 34 to a constant voltage source (not shown). The output of the one shot circuit 33 is connected via a resistor 35 to the gate of the trigger SCR 9. Furthermore, the one shot circuit 33
The output of is connected to the base of the transistor 22 via an inverter 24 and a resistor 23, and
Connected to the other input of AND gate 19. In this circuit, when a signal indicating that the shutter curtain is fully opened is input from the camera-side circuit 2 to the one-shot circuit 33 via the terminal _J2 , the one-shot circuit 33 outputs a one-shot pulse. This pulse has a pulse width longer than the total light emission time of the xenon tube 10, for example, about 1 msec. This pulse passes through resistor 35 for triggering.
It is applied to the gate of SCR9 and turns on the trigger SCR9. By turning on the trigger SCR 9, the xenon tube 10 is triggered, and the xenon tube 10 starts emitting light. At the same time, for driving the xenon tube.
The SCR 11 is turned on and the xenon tube 10 continues to emit light. Further, the output pulse of the one-shot circuit 33 is inverted by the inverter 24 and applied to the base of the transistor 22 to turn off the transistor 22, and is also applied to the other input terminal of the AND gate 19 to set the output of the AND gate 19 to a low level. Invert.

Light reflected from the object enters the camera through the photographing lens 36 and diaphragm 37 of the camera, and the photovoltaic element 38 provided in the camera-side circuit 2 receives this light. This photovoltaic element 38 is connected to an operational amplifier 39 with high input impedance, and a logarithmic compression diode 40 is connected between the output and -input of this operational amplifier 39. Logarithmically compressed voltage is output. The output of the operational amplifier 39 is connected to a variable resistor 4 for setting film sensitivity.
1 and a reference voltage source 42, and the output voltage of the operational amplifier 39 is changed by this parallel circuit in accordance with the film sensitivity setting and applied to the base of the transistor 43. This transistor 43 is a logarithmic and expansion transistor, and has an integral capacitor 44 and a shutter first transistor at its collector.
A parallel circuit of a switch 45 is connected which is opened in synchronization with the start of the shutter curtain travel, and when the switch 45 is opened in synchronization with the start of the shutter first curtain travel, charging of the integrating capacitor 44 is started. When the integrating capacitor 44 is charged to a predetermined level, the output of the comparator 46 connected to the collector of the transistor 43 is inverted to high level. The light emission stop signal which is the output signal of this comparator 46 is sent to the OR gate 47 and the terminal
It is transmitted to the strobe side circuit 1 via _J4 .

In the strobe side circuit 1, the terminal _J4 is connected to the + input of the comparator 48, and the - input of the comparator 48 is connected to the terminal J4.
A reference voltage source 49 is connected to the input. The output of the comparator 48 is inverted to a high level when the voltage value of the light emission stop signal transmitted from the camera side circuit 2 is higher than the voltage of the reference voltage source 49. The output of this comparator 48 is connected to one input of an AND gate 50, and the output of this AND gate 50 is
It is connected to the gate of the SCR 14 for stopping light emission via the OR gate 51. When the output of the comparator 48 is inverted to high level, the light emission stop SCR 14 is triggered when the other input of the AND gate 50 is high level, and the light emission of the xenon tube 10 is stopped.

In the camera side circuit 2, a switch 52 that is opened in synchronization with the release of the shutter is connected to a one shot circuit 53.
The output of transistor 54 is connected to the base of transistor 54 via a resistor. The collector of this transistor 54 is connected to terminal _J3 . In this circuit,
When the switch 52 is opened in synchronization with the shutter release, the one-shot circuit 53 outputs 1 msec.
A one-shot pulse having a pulse width of about 100 volts is output, turning on the transistor 54. By turning on the transistor 54, the terminal _J3 is grounded.

The terminal _J3 is connected to the emitter of the transistor 55 via a resistor in the strobe side circuit 1.
A reference voltage source 5 is connected to the collector of this transistor 55.
6 is connected. Further, the base of transistor 55 is connected to the output of the aforementioned AND gate 19 via a resistor. In this circuit, the charge completion signal of the main capacitor 5 output from the comparator 17 mentioned above is applied to the base of the transistor 55 via the AND gate 19, turning the transistor 55 on. By turning on the transistor 55,
The output voltage of the reference voltage source 56 is transmitted to the camera side circuit 2 via the terminal _J3 as a strobe charge completion signal.

The emitter of transistor 55 is connected to the base of transistor 59 via resistors 57 and 58, and the emitter of transistor 59 is grounded. The collector of the transistor 59 is connected to a constant voltage source (not shown) via a resistor.
The connection point between the collector of 9 and the resistor is AND gate 6
Connected to the 0 input. On the other hand, transistor 55
The emitter of is further connected to the base of a transistor 62 via a resistor 61, and this transistor 6
The second emitter is grounded. The collector of transistor 62 is connected to a constant voltage source (not shown) via a resistor, and the connection point between the collector of transistor 62 and the resistor is connected to the input of AND gate 60 via inverter 63. AND gate 60
The input of is further connected to the output of the comparator 48 mentioned above, and the output of this AND gate 60 is connected to the input of a one-shot circuit 64. In the circuit described above, when charging of the main capacitor 5 is completed and the output of the comparator 17 is inverted to a high level and the transistor 55 is in the on state, when the shutter is released, the switch 52 is opened. A one-shot pulse having a pulse width of about 1 msec is output from the one-shot circuit 53, and at this time, the terminal _J3 is grounded on the camera side for about 1 msec, and the collector voltage of the transistor 59 on the strobe side becomes high level. On the other hand, since transistor 55 is on at this time, transistor 6
2 is also turned on, the collector voltage of this transistor 62 is at a low level, and this signal is sent to the inverter 6.
3 and input to the AND gate 60. At this time, AND gate 60
Since all three inputs are at high level, the output thereof is at high level and triggers the one shot circuit 64. At this time, the one-shot circuit 64 outputs a one-shot pulse having a pulse width of about 200 msec, which is longer than the time from shutter release to full opening of the shutter curtain.

The output of the one shot circuit 64 is the OR gate 31
It is connected to one input of the AND gate 50 through the gate. Further, the output of the one-shot circuit 64 is connected to the other input of the AND gate 28 via an inverter 65. In this circuit, the one shot pulse output from the one shot circuit 64 is
It is input to the AND gate 50 via the OR gate 31, and at this time, if the light emission stop signal is output from the camera side and the output of the comparator 48 is at a high level,
The output of AND gate 50 becomes high level, and this signal passes through OR gate 51 to SCR1 for stopping light emission.
4 and turns on the light emission stop SCR 14 to stop the xenon tube 10 from emitting light.
Alternatively, the one-shot pulse output from the one-shot circuit 64 is inverted by the inverter 65 and becomes a low level, thereby prohibiting the output signal of the comparator 26 from passing through the AND gate 28.

Further, in the camera side circuit 2, one terminal of a switch 66 that is closed in the aperture priority mode and opened in the programmed aperture mode is grounded, and the other terminal is connected to a constant voltage source (not shown) via a resistor. Ru. The connection point of this switch 66 with the resistor is AND
connected to one input of gate 67, and this AND
One-shot circuit 53 is connected to the other input of gate 67.
The output of AND gate 67 is connected and the output of AND gate 67 is OR.
Connected to the other input of gate 47. In this circuit, when the aperture mode of the camera is the aperture priority mode, the switch 66 is closed and the output of the AND gate 67 becomes low level. On the other hand, in the program aperture mode, the switch 66 is opened, and when the switch 52 is opened by the shutter release and a one-shot pulse is output from the one-shot circuit 53, this pulse passes through the AND gate 67 and is ORed. The signal is input to the comparator 48 of the strobe side circuit 1 via the gate 47 and the terminal _J4 .

Next, the operation of the above circuit will be explained.

If the aperture control mode of the camera is set to the programmed aperture mode, which determines the aperture by considering the surrounding light of the main subject, and the switch 66 is in the open state, the power switch 2 is closed and the main capacitor 5 is closed. When charging is complete, comparator 1
The output of No. 7 is at a high level. On the other hand, since the output of the one shot circuit 33 is at a low level, the output of the inverter 24 becomes a high level, the output of the AND gate 19 becomes a high level, turning on the transistor 55, and the strobe charge completion signal is sent to the camera via the terminal _J3 . It is transmitted to the side circuit 2.

At this point, when the shutter is released,
The switch 52 is closed and the one shot circuit 53
A one-shot pulse having a pulse width of about 1 msec is outputted, turning on the transistor 54 and grounding the terminal _J3 . As described above, the aperture control mode of the camera is set to the program aperture mode and the switch 66 is in the open state, so the output of the AND gate 67 is inverted to a high level for about 1 msec. This signal is transmitted from the terminal _J4 to the strobe side circuit 1 via the OR gate 47. This signal indicates that the camera is in a mode in which the aperture control is performed in consideration of the ambient light of the main subject and the strobe light emission amount restriction is canceled. At this time, the terminal _J3 of the transistor 59 is grounded, so it is turned off, and the collector voltage of the transistor 59 becomes high level. In addition, the transistor 55
is on, so the transistor 62 is on,
The collector voltage of this transistor 62 becomes low level, and this signal is inverted to high level by inverter 63. Here, AND gate 6
0 becomes a high level, the one shot circuit 64 is triggered, and the one shot circuit 64 outputs a one shot pulse having a pulse width of, for example, about 200 msec, which is longer than the time from shutter release to full opening of the shutter curtain.

Subsequently, when the shutter curtain of the camera is fully opened, the switch 32 is closed, the terminal _J2 is grounded on the camera side, and the one shot circuit 33 of the strobe side circuit 1 is triggered. Here, the one-shot circuit 33 outputs a one-shot pulse having a pulse width of, for example, about 10 msec, which is longer than the total light emission time of the xenon tube 10. This pulse is applied to the gate of trigger SCR9 and trigger SCR9
is turned on, and the xenon tube 10 is triggered. At this point, the xenon tube 10 starts emitting light. Simultaneously with the triggering of the xenon tube 10, the xenon tube driving SCR 11 is turned on, and the xenon tube 10 continues to emit light.

Here, the light emitted from the xenon tube 10 is received by the photovoltaic element 20, and a photocurrent is generated in the photovoltaic element 20. At this time, since the output of the inverter 24 is at a low level, the transistor 22 is off, and if the strobe light emission limit mode is selected and the switch 25 is open, the integrating capacitor 21 is charged, and the transistor 22 is off. The charging voltage is compared with the output voltage of the reference voltage source 27 in the comparator 26, and when the charging voltage of the capacitor 21 becomes larger than the output voltage of the reference voltage source 27, the output of the comparator 26 is inverted to high level. However, in this case, since the output of the one-shot circuit 64 is high level and the output of the inverter 65 is low level, the comparator 2
The high level signal which is the output of 6 is AND gate 2
8 and is not applied to the gate of the SCR 14 for stopping light emission. In other words, the setting of the light emission amount limitation becomes invalid.

When the shutter is released, the reflected light from the subject enters the photographic lens 36 and the diaphragm 37 and is received by the photovoltaic element 38. The signal is logarithmically compressed, level-adjusted by a circuit consisting of a variable resistor 41 and a constant voltage source 42, and applied to the base of a transistor 43. At this time,
The switch 45 is opened in synchronization with the start of the first shutter curtain run, and the integrating capacitor 44 is charged with a time constant corresponding to the base input of the transistor 43. Here, when the photometric value, that is, the exposure reaches a proper value, the output of the comparator 46 is inverted to a high level, and this high level signal is transmitted to the strobe side circuit 1 as a light emission stop signal via the terminal _J4 . This light emission stop signal is passed through a comparator 48 to an AND gate 5.
On the other hand, since the output of the one-shot circuit 64 is at a high level at this time, the other input of the AND gate 50 is also at a high level, and therefore the output of the AND gate 50 is at a high level. This signal is applied to the gate of the SCR 14 for stopping light emission through the OR gate 51,
Turn on SCR14 for stopping light emission and turn on xenon tube 1
Stops the light emission of 0. In addition, in this case, since the output of the one-shot circuit 64 is at a high level,
The output of the OR gate 31 becomes high level, and the light emission of the xenon tube 10 is stopped by the light emission stop signal transmitted from the camera side circuit 2, regardless of whether the switch 30 which manually limits or non-limits the amount of light emitted is opened or closed. Ru.

When the aperture control of the camera is set to aperture priority mode, the switch 66 is opened and the output of the AND gate 67 becomes low level. The switch 52 is opened by the shutter release, and a one-shot pulse is output from the one-shot circuit 53, turning on the transistor 54 for a period of about 1 msec. Here, the terminal J ₃ is grounded, the transistor 59 is turned off, and the collector voltage of the transistor 59 is at a high level, and the transistor 62 is turned on, the collector voltage of the transistor 62 is at a low level, and the output of the inverter 63 is becomes a high level, but since the output of the AND gate 67 of the camera side circuit 2 is a low level, the terminal _J4 becomes a low level, so the output of the comparator 48 becomes a low level, and the output of the AND gate 60 becomes a low level. The output becomes low level. For this reason, the one-shot circuit 6
The output of inverter 4 is at low level, and the output of inverter 65 is at high level.

Next, when the shutters were fully opened, switch 32
is closed, the one-shot circuit 33 of the strobe side circuit 1 is triggered, and the one-shot circuit 33 to 10
A one-shot pulse with a pulse width of about msec is output. This pulse is applied to the gate of the trigger SCR9, and the trigger SCR9 turns on.
The xenon tube 10 starts emitting light. Further, the one shot pulse output from the one shot circuit 33 is inverted to low level by the inverter 24 and applied to the base of the transistor 22, turning off the transistor 22. At this time, if the light emission amount limiting mode of the strobe is selected and the switch 25 is opened, the photovoltaic element 20 receives the light emitted from the xenon tube 10, and the photocurrent generated in the photovoltaic element 20 is integrated. Capacitor 21 is charged. The charging voltage of the integrating capacitor 21 is compared with the output voltage of the reference voltage source 27 in the comparator 26, and when the charging voltage of the integrating capacitor 21 becomes larger than the output voltage of the reference voltage source 27, the comparator 26
output is inverted to high level. At this time, the output of the inverter 65 is at a high level, so the AND
The output of the gate 28 is inverted to a high level, and this signal is applied to the gate of the light emission stop SCR 14 via the OR gate 51, turning on the light emission stop SCR 14 and causing the xenon tube 10 to stop emitting light. In other words, the light emission restriction setting becomes valid.

In addition, in this case, when the manual light emission restriction release mode is selected and the switch 30 is in the closed state, the output of the OR gate 31 becomes low level,
The output of AND gate 50 becomes low level,
The light emission stop signal transmitted from the camera side circuit 2 is blocked.

Effects As explained above, according to the present invention, even when the aperture area of the camera diaphragm is controlled to be relatively small according to external light, the flash light emitting means has a main light emitting capacity within the range of its light emitting ability. It can give the appropriate amount of light to the subject,
It becomes possible to take a photograph with proper exposure for both the main subject and the surroundings.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a flash photography system according to the present invention, and FIG. 2 is a partial cross-sectional view showing an embodiment of a flash device used in the flash photography system of the present invention. be. 10... Flash light emitting means, 32, 33...
Light emission start signal output means, 38, 39, 40... Light receiving means, 44... Integrating means, 46... First light emission stop signal output means, 25... Switching means, 20, 2
1, 26, 27... Second light emission stop signal output means, 6, 7, 8, 9... Light emission start means, 11, 1
2, 13, 14... Light emission stopping means, 66... Selection means, 28, 50, 64, 65... Setting means, J ₃
...Emission start signal input means, J ₄ , 48, 49, 5
0...first light emission stop signal input means, J ₄ , 48,
49, 60...Mode signal input means.

Claims (1)

[Scope of Claims] 1. A flash light emitting means, a light emission start signal output means for outputting a light emission start signal in connection with the shutter operation, a light receiving means for receiving reflected light from a subject, and an integrated output of the light receiving means. Compare the integral value of the integrating means with a predetermined value,
a first light emission stop signal output means that outputs a first light emission stop signal when the integral value reaches the predetermined value; a first light emission mode that allows the flash light emission means to emit light up to its maximum light emission amount; a second light emission mode that limits the light emission amount of the flash light emitting means to a predetermined light emission amount or less that is less than the maximum light emission amount thereof; and a switching means for switching between a second light emission mode and a second light emission mode; reaches the predetermined amount of light emission, the second
a second light emission stop signal output means for outputting a light emission stop signal; a light emission start means for causing the flash light emitting means to start emitting light in response to the light emission start signal; a light emission stopping means for stopping the light emission of the flash light emitting means in response; and a selection means for selecting one from a plurality of aperture control modes including an automatic aperture control mode for automatically controlling the aperture according to external light. A flash photographing system comprising: a setting means for setting a first light emission mode independently of the switching means when the automatic aperture control mode is selected. 2. The flash photographing system according to claim 1, wherein the light receiving means receives object light incident through a photographing lens. 3. The second light emission stop signal output means includes a light receiving means that directly receives the flash light from the flash light emitting means, an integrating means that integrates the output of the light receiving means, and an integral value of the integrating means and the predetermined value. and output means for comparing the integrated value with a value corresponding to the amount of light emission and outputting a second light emission stop signal when the integrated value reaches a value corresponding to the predetermined amount of light emission. Range 1
The flash photography system according to any one of Items 1 and 2. 4 Select one from a plurality of aperture control modes, including a light emission start signal output means that outputs a light emission start signal in connection with the shutter operation, and an automatic aperture control mode that automatically controls the aperture according to external light. A flash device for use with a camera body having a selection means for outputting a mode signal corresponding to the selected aperture control mode, the flash device comprising: a flash light emission means; and a light emission start signal for inputting the light emission start signal. input means; a light emission start means for causing the flash light emitting means to start emitting light in response to the light emission start signal; and inputting a first light emission stop signal indicating that the amount of reflected light from the subject has reached a predetermined value. a first light emission stop signal input means; a first light emission mode that allows the flash light emission means to emit light up to its maximum light emission amount; and a predetermined light emission mode in which the light emission amount of the flash light emission means is lower than the maximum light emission amount. a switching means for switching between a second light emission mode and a second light emission mode that limits the light emission amount to a level below the amount of light emitted by the flash light emitting means; a second light emission stop signal output means for outputting the light emission stop signal; a light emission stop means for stopping the light emission of the flash light emitting means in response to the first or second light emission stop signal; and a mode signal input means for inputting the mode signal. and a setting means for setting the first light emission mode independently of the switching means when the automatic aperture control mode is selected. 5. The flash device according to claim 4, wherein the first light emission stop signal is output from the camera body. 6. The camera body is provided with means for receiving and integrating the subject light incident through the photographic lens, and outputting the first light emission stop signal when the integrated value reaches a predetermined value. A flash device according to claim 5, characterized in that: 7. The second light emission stop signal output means includes a light receiving means that directly receives the flash light from the flash light emitting means, an integrating means that integrates the output of the light receiving means, and an integral value of the integrating means and the predetermined value. and output means for comparing the integrated value with a value corresponding to the amount of light emission and outputting a second light emission stop signal when the integrated value reaches a value corresponding to the predetermined amount of light emission. Range 4th
7. The flash device according to any one of items 6 to 6.