JPH0640183B2 - Camera system - Google Patents

Description

The present invention relates to a camera system including an electronic flash device and a camera.

If a conventional flash discharge tube is used in a camera with a focal plane shutter, exposure unevenness will occur unless the electronic flash device emits light while the shutter is fully open.
It is necessary to manually set the shutter speed to a speed lower than the expected time when the above-mentioned unevenness does not occur, and at this time, there is a concern that the shutter speed may be erroneously set. In order to solve this, the power of the electronic flash device and the completion of charging of the main capacitor are detected, and the signal is transmitted to the camera,
There is one that automatically sets the shutter speed at the second when exposure unevenness does not occur, but this is the same signal used in both a small electronic flash device with a relatively short light emission time and a larger electronic flash device with a long light emission time. Therefore, the shutter speed is always automatically set to a shutter speed corresponding to an electronic flash device having a long light emission time, and there is a drawback that the stop motion effect of the electronic flash device having a short light emission time cannot be fully utilized.

On the other hand, a method of preventing uneven exposure by forcibly stopping the light emission of the electronic flash device by an electric signal for starting the trailing curtain of the focal plane electric shutter has also been devised. In this case, the total amount of light of the electronic flash device is not used, and when the exposure is insufficient due to the emission being stopped midway, it is not possible to know it before shooting, and it is only after the shooting that the exposure is insufficient. It could only be displayed. As described above, when the total amount of light is not available, there is a drawback that the range of automatic light control photography is narrowed by an unpredictable amount on the long distance side.

As another method, an electric signal for stopping the light emission of the automatic light control electronic flash device can be transmitted to the camera, and the closing operation of the shutter rear curtain can be started by the signal.
However, it takes at least 2-3 ms before the rear curtain actually closes both sides, so if it remains as it is, the shutter speed will be very long, and it will be easily affected by light sources other than the flash discharge tube. You will end up shooting photos that are blurred or have unnatural colors.

Therefore, a method of issuing a signal prior to the light emission stop signal of the electronic flash device in anticipation of the rise time of the trailing curtain has been considered, but in many electronic flash devices, the total light emission time is only a few ms. Even if a signal was sent to the trailing curtain immediately, the shutter speed would be longer than the necessary and sufficient shutter time, so it was not an effective system.

The present invention adjusts the flash light emission time to the shortest maximum flash light emission time in a range where exposure unevenness does not occur in a flash device in which the maximum flash light emission time is variable with respect to the shutter speed set automatically or manually, and In a flash device with a fixed maximum flash emission time, a camera system that displays the maximum shutter speed that can be synchronized with a fixed maximum flash emission time to realize the photographer's shooting intention without failing to shoot and to save light emission energy , And a camera and an electronic flash device used in the camera system.

According to the present invention, the camera side is provided with an output means for outputting a signal according to the shutter speed set automatically or manually to the electronic flash device, and the electronic flash device side compares the first flash time with the signal. The comparison means is provided. As a result, if the electronic flash device has a fixed maximum flash light emission time, for example, if the electronic flash device is provided with a display device capable of comparing a set shutter speed with a fixed maximum flash light emission time, A camera system capable of setting the maximum shutter speed that can be tuned with the fixed maximum flash emission time is possible with reference to the display. Further, in the case where the electronic flash device is capable of adjusting the maximum flash light emission time, if the electronic flash device is provided with a display device capable of comparing the set shutter speed and the maximum flash light emission time set by the adjustment, A camera system capable of setting the longest maximum flash emission time that can be tuned at the shutter speed set with reference to the display is possible, and further, a signal corresponding to the shutter speed set in the electronic flash device is input. A camera system in which the longest maximum flash time that can be tuned at the shutter speed set by the camera is automatically set if the flash device is provided with a device for controlling the longest maximum flash light emission time that can be synchronized at the shutter speed. Is possible. The fastest shutter speed that can be tuned at a certain time is the fastest shutter speed at which the aperture is fully opened at least during that time. Further, the longest maximum flashing time that can be tuned at the set shutter speed means at least the longest flashing time that does not exceed the full opening time of the aperture.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram for explaining the present invention. This figure shows
A camera body 1 and an electronic flash device 2 which can be installed therein are generally shown. The electronic flash device 2 is provided with a mounting foot 3, and the camera body 1 is provided with a mounting seat 4, and the mounting foot 3 can be coupled to the mounting seat 4. The camera body 1 is further provided with a shutter dial 5, and the shutter speed set here is indicated by the index 6. Further, the signal indicating the set shutter speed is transmitted from the camera body 1 to the electronic flash device 2 through one of the terminals of the terminal group 7 provided on the lower surface of the mounting foot 3.

FIG. 2 is a view showing a lower portion of the mounting foot 3 of the electronic flash device 2. The structure of the terminal group 7 is as follows. That is, it comprises a ready light terminal u, a shutter speed input terminal v ₁ , a synchronizing terminal x ₁ , a light emission stop signal input terminal y ₁ , and a ground terminal g ₁ . Of course, the mounting seat 4 of the camera 1 is also provided with a terminal group capable of contacting the terminal group 7. Here, the shutter speed signal will be described with reference to FIG. The shutter speed set by the camera body 1 is represented by a time difference t _s between the running curve b of the front curtain (not shown) and the running curve c of the rear curtain (not shown).
At this shutter speed t _s, the time t _f that can be used for the electronic flash device 2 to emit light is as follows.

_{t f = t s -t m -t} d -α where _{t m} curtain traveling time required to travel the first curtain of the Apachiya A, _{t d} is Synchro X from the time when the first curtain has fully opened the Apachiya A It shows the time until the contact turns on. α is a margin time set in anticipation of variation in the timing t _d of variations and X contact of shutter speed t _s.

More _t m of the time, _{t d,} alpha is shutter driving method,
For example, vertical running, lateral running, rotary, etc. differ depending on the structure of the synchro contacts, and thus differ depending on the camera model. Under such circumstances, the camera body 1 outputs a signal to the electronic flash device 2 in an amount corresponding to the length of the time t _{f that} can be used for the electronic flash device 2 to emit light. The electronic flash device 2 inputs this signal and compares the time t _f with the light emission time of the electronic flash device by, for example, a built-in comparison circuit. When the time t _f is shorter than the light emission time, a warning is given. The comparison circuit and the warning method will be described in detail later.

Here, the emission characteristics of the general electronic flash device 2 tend to concentrate the emission amount in the first half as shown in the upper diagram of FIG. The horizontal axis t represents time, and the vertical axis I represents emission intensity. Since the light amount of the portion minus the tail of the emission end of life at this time graph is relatively small, considered a light emission time of the electronic flash device to be compared with the time t _f and t _{f 'in} Figure instead total light emission time t _f You can also

FIG. 4 shows the back surface of the electronic flash device 14 that can be mounted on the camera body 1 of the embodiment. The light emission amount selector 15
When the light amount is FULL, the total light amount can be used, when the light amount is 1/2, the light amount can be 50%, and when the light amount is 1/4, the light amount can be 25%. Both the electronic flash device 2 of FIG. 1 and the flash device 14 of this figure can be applied to the present invention regardless of the presence or absence of the automatic light control function.

The electronic flash unit 14 receives a signal representing the shutter speed t _f from the camera body 1 and compares the shutter speed t _f with the light emission time selected by the selector 15. And the light-emitting time at the time longer than t _f lamp 16 to warn flashing. At this time, the shutter dial 5 of the camera body 1 may be operated to switch to a longer shutter speed, or when the amount of light is sufficient for the subject, the selector 15 is switched to 1/2 or 1/4. The flash duration may be reduced.

FIG. 5 shows the light emission characteristics. That is, the emission characteristics at the time of each emission of FULL, 1/2, and 1/4 are d, g, and g
Indicated by. For example, when the shutter speed is increased manually by operating the selector 15 with respect to the manually set shutter speed, and when it exceeds the time corresponding to the shutter speed set by the camera, the lamp 16 blinks and a warning is issued. To do. The lamp 16 is turned off by operating the shutter dial 5 to make the shutter speed longer than the maximum flash emission time selected by operating the selector. At this time, exposure unevenness does not occur even if the shutter speed is shortened to the lengths of t _f1 , t _f2 , and t _f3 .

In order to further shorten the total light emission time in the FULL light emission mode, the light emission can be stopped at the final stage where it hardly contributes to the actual exposure as shown by the curve h.

FIG. 6 shows a shutter dial 5 according to the second embodiment of the present invention. Overhanging part 5 on part of the outer circumference of the shutter dial 5
A is provided and the upper limit of the light emission time given to the electronic flash device 2 is displayed there. With this camera, 1 /
When 125 seconds and 1/60 seconds are opposed to the index 6, 1 /
The number indicating 4 and FULL faces index 7. In addition, since the X display is 1/90 second in this embodiment, the display of 1/2 is opposed to the index 6 at that time. Therefore, referring to this, the selector 15 of the light emitting device shown in FIG.
It can be used according to either 2 or FULL.
Also, since the time required for FULL, 1/2, and 1/4 light emission differs depending on various flash devices, it is possible to cope with various flash devices by displaying by time.

FIG. 7 shows an input section for inputting a shutter speed signal provided in the electronic flash device. This is a system in which mechanical displacement is used as a shutter speed signal and transmitted to the electronic flash device 2. First, the mechanism on the camera body 1 side will be described with reference to FIG. FIG. 8 shows a means for outputting a signal of the shutter speed set by the camera. A cam 17 is fixed below the shutter dial 5 and rotates integrally with the dial 5. There is a concentric circle portion 17 on the cam 17, which is 1 /
It corresponds to the shutter speed range such as 1000 seconds and 1/500 seconds where flash photography is not possible with the focal plane shutter.

The radius of the next portion 17b is sequentially changed according to the shutter speed. The portion 17b is connected by a smooth curve in this figure, but it may be stepwise. The area of the next portion 17a corresponds to the shutter speed area in which the flash photography can be performed sufficiently for a long time. This part 17a
Can be concentric. The lift of this cam 17 is the lever 18
The direction is changed by. The lever 18 is biased in a clockwise direction by a spring 20 around a shaft 19. Therefore, the pin 21 planted at one end of the lever 18 approaches the mounting seat 4 when the lift of the cam 17 is large, and moves away when the cam 17 is small.

A hook 22 for preventing the electronic flash device 2 from being detached is also provided so that the stroke of such a signal can be reliably transmitted.

The above is provided in the camera body 1 of the present embodiment.

FIG. 7 shows an example of the electronic flash device 2 that receives a signal from the camera body 1 of this embodiment.

The lever 23 of the mounting foot 3 is rotatable about an axis 24, and when the lever 23 is rotated to the left by contact between the pin 21 and the tip 23a of the lever 23 when the lever 23 is inserted into the mounting seat 4 of the camera body 1. To do. This counterclockwise rotation angle is electrically detected by a variable resistor or the like in the electronic flash device 2 as a shutter speed signal. Since this detection can be performed by a known method, it will not be described in detail.

Although the shutter dial 5 on the camera side is provided with the means for displaying the maximum flash emission time, the shutter speed set by the shutter dial 5 is displayed near the selector 15 on the flash device side. Therefore, the maximum flashing time can be appropriately selected and set by the selector 15.

In the above embodiments, a plurality of shutter speed signals are output according to the setting value of the shutter speed in the camera body 1, but the shutter speed signal is output only when the shutter speed is set at a specific X seconds. However, this system is sufficiently effective. Generally, the X-second time differs depending on the camera model, but the photographer should perform flash photography without taking into consideration the model difference of the margin with respect to the light emission time of the electronic flash device 7 when the X-second is set. Because you can

FIG. 9 shows a specific example of the circuit of the electronic flash device.

The power supply 30 supplies power to the entire circuit via the power switch S ₁ . The power supply voltage is boosted by the booster circuit 31 and charged in a main capacitor (not shown). When the charging voltage reaches a predetermined value, the voltage detection unit 32 generates a light emission enable signal and outputs the signal to the terminal u. ₁ to the camera body 1 side. When the X contact is turned on, an issue start signal is transmitted to the light quantity control unit 33 via the synchro terminal x ₁ , and the light quantity control unit 33 causes the flash discharge tube 34 to start flash emission.

The constant current source 35 generates constant currents I ₀ and I ₁ proportional to the absolute temperature. The resistors R _{2 to} R ₅ and the switch S ₃ set the maximum light emission time of the flash discharge tube, and therefore generate a voltage signal whose magnitude is inversely proportional to the maximum light emission time. The constant current source I ₂ , the diode D ₁ , the operational amplifier 36, the integrating capacitor C ₁ , the transistor Q ₂ , the operational amplifier 37, the resistor R ₆ , the zener diode D ₂ , and the comparator 38 are
The voltage signal is input to generate a light emission stop signal that defines the maximum flash light emission time. These resistors R _{2 to} R ₅ , switch S ₂ , comparator 36, diode D ₁ , constant current source I ² , capacitor C, transistor Q ₂ , operational amplifier 37, zener diode D ₂ , comparator 38.
Constitutes a light emission time limiting means. Comparator 39,
The capacitor C ₂ and the photodiode 40 form an automatic light control circuit. The automatic light control circuit measures the flash light emission amount and generates a light emission stop signal when it reaches a predetermined amount. The light emission stop signal of the light emission time limiting means and the automatic light control circuit is applied to the light quantity control unit 33 through the switches S ₄ , S ₅ and the OR gate G ₁ to stop the light emission. The terminal y ₁ inputs a light emission stop signal from the camera body 1 when so-called TTL light control is performed, and similarly applies the light emission stop signal to the light amount control means 33 via the switch S ₆ and the OR gate G ₁ , the switch S ₂ , the resistance R ₁ ,
The transistor Q ₁ , the resistor R ₆ , the resistor R ₈ , and the transistors Q ₃ and Q ₄ form a reset circuit. The transistors Q ₁ , Q ₃ , and Q ₄ are always in the ON state, and the capacitors C ₁ and C ₂ are respectively in the ON state. Is short-circuited (that is, in reset state) and waiting. During shooting operation (that is, X contact is O
Only when (N), the transistors Q ₃ and Q ₄ are turned off, integration of the capacitors C ₁ and C ₂ is started, and the light amount is controlled by the light emission stop signal of the comparator 38 or 39, whichever operates first. After that, when the shutter is closed and the X contact is turned off, the transistors Q ₁ , Q ₃ and Q ₄ are turned on again.
The capacitors C ₁ and C ₂ are reset to prepare for the next shooting. The switch S ₂ is a switch for causing the flash device to emit light without operating the camera during the test.

The terminal v ₁ for inputting a voltage according to the shutter speed from the camera side constitutes a shutter speed input means. The comparator 41, the AND gate G ₂ , the oscillator 42, and the light emitting diode 43 form a comparison circuit. This comparison circuit inputs a voltage according to the maximum light emission time and the manually set shutter speed from the switch S ₂ and the terminal v ₁ , respectively, and blinks the light emitting diode 43 at the frequency of the oscillator 42 when the shutter speed is shorter. And warn. In this case, the switch S ₃ linked to the selector 15 shown in FIG. 4 is operated to shorten the maximum light emission time, or the shutter speed of the camera shown in FIGS. 6 and 7 is manually operated to operate the shutter speed. Slow down. When the shutter speed becomes longer than the maximum flash emission time, the light emitting diode 43 is turned off and the warning is released.

Here, the setting of the maximum light emission time by the light emission time limiting means will be described in detail. In the figure, the voltage generated in the resistors R ₄ and R ₅ is applied to the non-inverting input terminal of the OP amplifier 36 as a voltage corresponding to the maximum flash emission time. A constant voltage is input to the non-inverting input terminal of the OP amplifier 37, and its output terminal and inverting input terminal are connected to the emitter of the transistor Q ₂ . The diode-connected transistor D ₁ and transistor Q ₂ form a logarithmic compression-expansion circuit of current. Yotsute selected resistance value switch S _2, for example, in the case of the figure the R ₄ + R ₅ and R _N, also generates a non-inverting voltage applied to the input terminal of the OP amplifier 37 resistors, for example of the figure when the _R 4 + _{R 5} and _{R N.} Therefore, the voltage at the non-inverting input terminal of the OP amplifier 36 is R
_N I ₁ , the voltage of the non-inverting input terminal of OP amplifier 37 is R _K I
_Since it can be written as ₁ , the following equation holds.

Here K: Boltzmann constant, q: electron charge, T: absolute _temperature, I _s: D _1, reverse saturation current of _{Q 2,} I c: a _{Q 2} in the collector current. If I _c is _calculated from this, Since I ₁ is proportional to the temperature, it can be expressed as I ₁ = AT (constant). Substituting this equation into and deleting I ₁ , the result is as follows.

Furthermore, by appropriately selecting the values of R _N and R _K , I _c
Can be an exponential current change with base 2.
Since the integrating capacitor C ₁ is charged by this current, the charging voltage V _c of the capacitor C ₁ is Becomes This voltage is compared by the comparator 38 with the reference voltage generated by the Zener diode D ₂ .

Here, if the voltage of the Zener diode D ₂ is V _ref ,
In the equation, t where V _ref = V _c gives the maximum flash emission time.

Next, the operation will be described. First, the switch S ₃ is operated to set the maximum light emission time. In FIG. 9, the voltage generated in the resistors R ₄ and R ₅ corresponds to the maximum light emission time.
This voltage is applied to the inverting input terminal of the comparator 41, while the voltage signal corresponding to the shutter time is applied to the front inverting input terminal of the comparator 41 via the terminal v ₁ . Then, when the shutter time becomes shorter than the maximum light emission time, the comparator 41 outputs the H output to the AND gate G
₂ is applied. Therefore, in this case, the output of the AND gate G ₂ becomes H and L at the frequency of the output of the oscillator 42, and the light-emitting diode 43 blinks to warn.

So, either shortening the flash light emission time by operating the switch S _3, or slowing the shutter speed. Then, the output of the comparator 41 becomes L, the light emitting diode 43 is turned off, and the warning is released.

Next, when the shutter release is performed, the front curtain fully opens the aperture, and then the X contact S ₇ is turned on and the transistors Q ₃ and Q are connected.
₄ is turned off, integration of the capacitors C ₁ and C ₂ is started, and one of the comparators 38 and 39 that operates earlier outputs a light emission stop signal to the light amount control unit 33.
After that, when the rear curtain fully closes the aperture, or when the X contact S ₇ is turned off during winding, the transistor Q ₁ ,
Q ₃ and Q ₄ are turned on, and the capacitors C ₁ and C ₂ are in a reset state, and then they are ready for photographing. In any case, the light emission time is limited to be shorter than the full opening time of the aperture.

FIG. 10 is a block diagram generally showing the camera body of the present invention to which the electronic flash device can be attached. The photometric circuit 50 measures the subject brightness (B _v value) and the lens F value (A _v value).
The circuit 51 generates a shutter time (T _v value). Circuit 52
Enter the film sensitivity. The exposure control circuit 53 is B _v
Value, S _v value, A _v value, T _v value, etc. are input, and shutter seconds etc. are calculated and controlled. Further, the camera body has an AD conversion circuit 5
4, a shutter information display circuit 55, an electronic flash device interface circuit 56, and a hot shoe 57. The hot shoe 57 has terminals u ₁₀ , v ₁₀ , w ₁₀ , x ₁₀ , y _10.
, Each of which is a terminal of an electronic flash device.
u ₁ , v ₁ , w ₁ , x ₁ , y ₁ are respectively associated and connected. The photometric circuit 58 is a photometric circuit when the electronic flash device 2 is mounted and TTL light control is performed. Switch S ₇ is an X contact. 11 to 17 show the circuits 56, 55, 58, 52, 50, 51 and 53 shown in FIG. 10, respectively. In FIG. 11, resistors 80 and 81, a transistor 82, a light emitting diode 83, a resistor 84, and a power source Vcc constitute a ready light.

Charging completion signal terminals u ₁ from the ninth illustrated voltage detecting unit 32,
It is applied to this ready light of FIG. 11 via u ₁₀ and RDY, and the light emitting diode 83 lights up to indicate the completion of charging.

FIG. 12 shows a specific circuit example of the shutter time display circuit 55. Resistors R401 to R411 and light emitting diode D
Reference numerals 401 to D411 form a display circuit for displaying the shutter speed. AND gates GA401 to 411, GB40
One to four hundred and eleven, OR gate G401～G411, inverters G412, G413, and switch _{S 9} is, A-D conversion circuit 54, when each Otoshiyatsuta seconds shutter-time-generating circuit 51, selectively inputs the time Maniyuaru shear ivy seconds And then display.

The light emitting diodes D401 to D411 display the shutter time of 1 second to 1/1000 second. Switch S ₉ is in switch for selecting whether the display when the display or Maniyuaru seconds when auto seconds, to display the time 1 / 1000-1 sec seconds by the output of the A-D converter circuit 54 becomes the ON, OFF When set to, the shutter speed by the output of the manual time circuit 51 is displayed.

FIG. 13 shows a photometric circuit 58 for TTL light control using an electronic flash device. This photometric circuit includes OP amplifiers 90, 91 and 92, a comparator 93, a light receiving photo diode 94, a logarithmic compression diode 95, transistors 96, 97 and 98, and zener diodes 99 and 10.
0, 101, 102 are included. FIG. 14 shows a circuit for generating a voltage proportional to the film sensitivity. This circuit includes resistors 103, 104, 105 and 106, a variable resistor 107 for introducing film sensitivity, an OP amplifier 108, transistors 109 and 110 having uniform characteristics, and a transistor 111.
including. FIG. 15 shows a photometric circuit 50 for measuring subject brightness. FIG. 16 shows a shutter time generation circuit for generating a voltage and a selection signal for setting a manual shutter time. This circuit includes OP amplifiers 112 and 113 and resistors 114 to 124, resistors 125 and 126 for generating a voltage corresponding to the shutter time of 1 second to 1/1000 second.
127 includes a switch S ₁₀ to S _11, which is used to select when shutter seconds switch interlocked. FIG. 17 is a block diagram of the exposure control circuit 53.

The exposure side control circuit 53 includes an arithmetic circuit 130, a second control circuit 131, and a magnet control circuit 132.

Next, the operation will be described.

First, when the charging of the electronic flash device is completed, a charging completion signal is applied to the terminal RDY of FIG. 11 through the terminals u ₁ -u ₁₀ .
The transistor 82 is turned on, and the light emitting diode 83 for indicating the completion of charging arranged in the finder of the camera is turned on.

Next, the operation of FIG. 12 will be described.

AND gates GA401, GB401, GA411, G
B411 and OR gates G401 to G411 are gates for switching the display. That is, switch S ₉
When is ON, the outputs of the AND gates GA401 to GA411 are all "L", so the shutter time (1 second to 1/10 in the figure) determined by the automatic second of the AD conversion circuit 54 is determined.
00 second) signal is applied to one of the AND gates GB401 to GB411, and the output "H" at the time of shuttering at that time is applied.
And the light emitting diodes D401 to D411 at that time
Lights up. The switch S ₉ is the That camera operation when the OFF signal when the shutter seconds from all "L" Maniyuaru seconds when generating circuit 51 outputs the AND gates GB401~GB411 Conversely now when performed in Maniyuaru AND gates GA401 to GA4, respectively
11 is applied to turn on one of the light emitting diodes D401 to D411 corresponding to the shutter time. FIG. 13 shows a photometric circuit of the electronic flash device. The photocurrent of the photodiode 94 _{I L,} the transistor 96
Is a collector current of I _C , and the voltages applied to the terminals SV-2 and SV-3 are V _S2 V _S3 . If the diode 85 and the transistor 98 have the same characteristics, the following equation holds.

If you ask for I _C The charging voltage of the integrating capacitor 89 is 0 when the X contact of the camera is O.
When N and the STA terminal becomes "L", the transistor 97,
When 98 is turned off, Becomes

The third term of this equation is at room temperature Therefore, (V _S3 −V _S2 ) is It shows that it changes by 2 ^N times. Therefore, it is shown that if the ASA sensitivity changes by 18 mv per step with the resistor 107, the amplification degree of the photocurrent can change correspondingly. When the charging voltage of the integrating capacitor 89 reaches the voltage of the Zener diode 99, the comparator 9
3 outputs if in the switch S ₆ of FIG. 9 through the contact y ₁ -y ₁₀ via the terminal STP of Figure 11 are output from "L" to "H" terminal STP to a side light amount control Part 33
The emission of the electronic flash device can be stopped. FIG. 14 is a circuit for generating a voltage proportional to absolute temperature. Since the transistors 109 and 110 have uniform characteristics, the reverse saturation current I
_{If S} is equal and h _FE is sufficiently large, the base current of the transistor 110 is negligible and cannot be used. Therefore, the following equation holds.

R ₁₀₃ I _A = R ₁₀₅ I _B If h _{FE of the} transistor 110 is sufficiently large, I _E ≈I _C This current is proportional to absolute temperature.
If the value of R ₁₀₇ is properly selected, a voltage proportional to absolute temperature will be generated at terminals S _{V-1 and} S _V-3 . If the GND of the variable resistor R ₁₀₇ and the potential at the middle point are V _SV (R _x is the resistance value between the midpoint of R ₁₀₇ and GND), and this voltage is also proportional to the absolute temperature.

FIG. 16 shows a shutter time generating circuit for generating a shutter time signal. The switching switch S ₁₀ S ₁₁ is an interlocking switch, and in this example, an analog voltage corresponding to 1 second to 1/1000 second is output from the switch S ₁₀ to the terminals MTV-1 and MTV-2 through the output of the OP amplifier 113. . The switch S ₁₁ outputs a digital signal corresponding to the shutter time to the terminal MTV-3. The OP amplifier 112 is the first
This is for voltage level conversion to input a voltage proportional to the absolute temperature from the terminal SV-3 in FIG. 4 and to make the voltage level appropriate for generating a voltage corresponding to the shutter time.

FIG. 17 is a detailed block diagram of the exposure control circuit 53. Arithmetic circuit 130 receives the output of the photometric amplifier terminal B _V, inputs the data when shutter seconds computed by entering the film sensitivity output terminal SV-1 seconds when the control circuit 131. The second control circuit 131 normally transmits the output of the arithmetic circuit 130 to the magnet control circuit 132 to control the shutter.

FIG. 18 shows a circuit of another electronic flash device. The points in FIG. 18 that are increased from those in FIG. 9 are comparators A _{1 to} A ₃
And AND gates G _{1 to} G ₃ , OR gate GD, resistance R _a
~ R _d .

The interlocked switches S ₄ and S ₅ are set to the side a, and the shutter time information from the camera is input to the OP amplifier 36 to control the flash time. At this time, it is assumed that resistors are connected to the flash time selection switch S ₃ as shown in the figure and the voltage between the resistors is determined as shown in the figure. In this example V
The voltages of _{1 to} V ₄ are determined according to the length of the flash duration, and V ₁ corresponds to the maximum flash duration, and V ₄ corresponds to the maximum flash emission duration. V _a is set to a voltage slightly higher than the voltage V ₁ representing the minimum flash time. Similarly, V _b is set to be a voltage slightly smaller than V ₄ . Further, V _c is set to a voltage slightly higher than the potential of GND.

To explain the operation, the comparators A ₁ A _{2 form} a window comparator, and determine whether the input voltage at the terminal v ₁ is between the minimum and maximum flash time of the electronic flash device. The comparator A ₃ is for determining whether the switching switch S ₄ is on the a ₁ side or the b ₁ side, and when S ₄ is set on the b ₁ side, the inputs of A _{1 to} A ₃ are Since the resistance has dropped to the GND level due to the resistance R _d, the output of A ₃ is set to “L” to disable the warning circuit. The AND gate GC ₂ blinks the light emitting diode 43 provided in the speedlight to warn that the proper range has been exceeded. At this time, the output of the AND gate GC ₃ gives a warning by blinking the light emitting diode 83 in the camera shown in FIG. 11 through the terminal u ₁ .

The truth table is shown on the next page.

Note Shiyatsutataimu information from the camera, the pin MTV-2 of FIG. 16, is transmitted from the v ₁₀ terminal by turning on the switch S ₈ of Figure 11 to the electronic flash device.

In the above description, an example in which the shutter speed is manually set has been described, but instead of the voltage generated by the manual setting, the output of the arithmetic circuit 130, that is, the voltage according to the shutter speed at the time of automatic exposure shooting is output means. Terminal CP-
2, v of course during an automatic exposure shooting if As tell ₁₀ also possible to apply the present invention.
Further, in the above description, the flash device which is separate from the camera has been described, but the present invention is also effective in a camera having an electronic flash device built therein. For example, there are cases where multi-flash photography is performed, and cases where another electronic flash device is additionally used to obtain a larger amount of light.

As described above, according to the present invention, the camera outputs a signal corresponding to the shutter speed to the electronic flash device, and the electronic flash device is configured to compare this signal with the light emission time of the electronic flash device itself. Therefore, a camera system capable of various operations can be obtained based on the comparison result. For example, if a warning device is provided, a warning can be issued if the shutter speed set on the camera side is shorter than the light emission time, and the photographer can be prompted to change the shutter speed. If a shutter speed automatic changing device is provided, the shutter speed can be automatically changed to an appropriate (tunable) shutter speed if the shutter speed is shorter than the light emission time.

[Brief description of drawings]

1 is a diagram showing an overview of a camera body and an electronic flash device, FIG. 2 is a diagram showing input / output terminals of the electronic flash device, FIG. 3 is a diagram showing light emission characteristics of the electronic flash device, FIG. FIG. 4 is a diagram showing an example of an electronic flash device, FIG. 5 is a diagram showing light emission characteristics of the electronic flash device shown in FIG. 4, FIG. 6 is a diagram showing a shutter time setting dial of the camera body, FIG. , FIG. 8 is a diagram showing a mechanism for mechanically transmitting the shutter time, FIG. 9 is a diagram showing a circuit of an electronic flash device, FIG. 10 is a block diagram showing an overall configuration of a camera, FIG. Shows an interface circuit, FIG. 12 shows a shutter time display circuit, FIG. 13 shows a photometric circuit included in an electronic flash device, and FIG. 14 shows a film sensitivity input circuit. Fig. 15 is a diagram showing a photometric circuit of the camera, 16 Figure is a view showing a time generating circuit shutters seconds, FIG. 17 is a diagram showing an exposure control circuit, FIG. 18 is a diagram showing a circuit of another electronic flash device. [Explanation of Signs of Main Parts] Outputting means: 17, 18, 19, 20, 21

Claims (3)

[Claims] 1. A camera comprising an electronic flash device having at least a first light emission time and a camera communicable with the electronic flash device and provided with a focal plane shutter composed of a first curtain and a second curtain. In the system, the camera includes a setting unit that sets a shutter speed, which is a time from when the first curtain starts retracting from the aperture to when the second curtain appears in the aperture, and the first curtain is the aperture. First storing means for storing the curtain traveling time required from the start of retracting the shutter to the completion of the retracting, and the light emission standby time from the completion of the retracting of the first curtain from the aperture to the contact of the synchro contacts. A second storage unit for storing the maximum flash memory capacity, the maximum shutter speed, the curtain travel time, and the light emission standby time, and The electronic flash device compares the first light emission time with the maximum light emission time. The electronic flash device compares the first light emission time with the maximum light emission time and outputs the maximum light emission time to the electronic flash device. A camera system having a comparison means. 2. An electronic flash device capable of communicating with an electronic flash device, comprising: a first light emission time; and a comparison means for comparing the first light emission time with a second light emission time. A focal plane shutter composed of a second curtain, setting means for setting a shutter speed which is a time from when the first curtain starts retracting from the aperture to when the second curtain appears in the aperture, and the first curtain First storage means for storing the curtain traveling time required from the start of retracting the aperture to the completion of the retracting, and the light emission from the completion of the retracting of the first curtain from the aperture to the contact of the synchro contacts. Second storage means for storing a standby time, and the second light emission time that the electronic flash device can use for light emission based on the shutter speed, the curtain travel time, and the light emission standby time. Camera and calculating means calculating for, the maximum emission time, and an outputting means for outputting to the electronic flash device. 3. A focal plane shutter composed of a first curtain and a second curtain, and a shutter speed which is a time from when the first curtain begins to retract from the aperture to when the second curtain appears in the aperture. Setting means; first storage means for storing a curtain traveling time required from the first curtain starting to retract the aperture to the completion of the retracting; and the first curtain after retracting from the aperture. The second storage means for storing the light emission standby time from the contact to the synchro contact, and the attached electronic flash device for emitting light based on the shutter speed, the curtain running time and the light emission standby time. It is possible to communicate with a camera having a calculating means for calculating the maximum light emission time that can be used and an output means for outputting the maximum light emission time to the electronic flash device. Comprising a light time, the electronic flash device, characterized in that it comprises a comparing means for comparing the first light emitting time and the maximum emission time.