JPH07117680B2 - Electronic flash device or camera incorporating it - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic flash device for a camera.

[0002]

2. Description of the Related Art Conventionally, there has been known an electronic flash device capable of switching between a light emission control mode (automatic light control mode) in which flash light emission is automatically stopped when a subject illumination light reaches a predetermined value and an all light emission mode. An electronic flash device having only one of the modes is also known. U.S. Pat. No. 421
No. 0849, etc., there is also known an electronic flash device having a so-called split light emission mode in which the charge energy of the main capacitor is divided by a fixed amount and a subject is illuminated by flash light emission according to the divided light emission energy. Has been. In such an electronic flash device, a calculator is prepared to facilitate photographing. By using a calculation plate, the light emission guide number, film sensitivity, subject distance,
The relationship between the aperture values of the taking lens can be easily obtained, and by setting the aperture value and the like according to the values read from the calculation plate, it is possible to take an image with proper exposure. However, if the operation or reading of the calculation plate is erroneous, or if the photographing conditions are changed but the conditions are forgotten, proper exposure cannot be obtained.

[0003]

SUMMARY OF THE INVENTION According to the present invention, if the operator makes a mistake in the operation or reading of the calculation board, or forgets to change the condition despite the change of the photographing condition, he / she does not notice it and shoots as it is. The purpose is to obtain a flash photography display device.

[0004]

According to the present invention, in an electronic flash device which emits flash light for photographing or a camera incorporating the electronic flash device, any one of aperture value information, guide number information and distance information of photographing information is selected. Creating means for creating a reference signal indicating an appropriate value of the remaining information not selected as the two pieces of information for flash photography, based on three pieces of information, two pieces of information and film sensitivity information; By giving a predetermined width to the signal, a predetermined width setting means for outputting a predetermined width signal having a permissible range to the proper value, and the remaining information that can be changed according to conditions are acquired and acquired. An acquisition unit that outputs an acquisition signal based on information, compares the acquisition signal with the predetermined width signal, and the acquisition signal is within a predetermined width of the predetermined width signal and outside the predetermined width. Display form in the case is that a display control means for controlling the display means so as to be different.
In the following description of the embodiments, the electronic flash device will be mainly described, but in the present invention, the electronic flash device may be built in the camera.

[0005]

EXAMPLES The present invention will be described below based on examples.
In the following description, the exposure factor is represented by apex display. FIG. 1 shows a camera side circuit, and FIG. 2 shows a flash device side circuit diagram.

The circuit on the camera side and the circuit on the electronic flash device side are connected via connection terminals T _{1 to} T ₆ of the accessory shoe 2. If the camera and electronic flash device are removable,
The connection terminals T _{1 to} T ₆ are conducted when the electronic flash device is attached to the camera.

The circuit on the camera side of FIG. 1 will now be described. When the power switch SW ₁ is turned on, the power source E ₁ supplies power between the power supply line Vcc _{1 and} GND. The switch SW ₂ is turned on by pressing the shutter button (not shown) up to the first stroke. The capacitor C ₁ is connected in parallel with the switch SW ₂ . The power supply control transistor Q ₁ is a switch SW ₂
Is ON, or when the switch SW ₂ is turned ON and then turned OFF, the capacitor C ₁ changes the resistance R ₀ ,
O until each is charged to a predetermined voltage via R _1.
N. The exposure control circuit 1 introduces an exposure factor from the variable resistors VR _{1 to} VR ₃ and the photodiode PD ₁ . The resistance value of the variable resistor VR ₁ changes according to the open aperture value AV ₀ of the lens. When the preset aperture value preset by a preset aperture ring (not shown) of the lens is generically referred to as AV, the variable resistor VR ₂ is a resistor according to the step difference AV ₀ −AV between the open aperture value and the preset aperture value. The value changes.
The resistance value of the variable resistor VR ₃ changes according to the film sensitivity SV. The photodiode PD ₁ is a light receiving element for TTL open photometry and generates a photometric output BV-AV ₀ . The exposure control circuit 1 calculates TV = BV + SV-AV at an appropriate shutter speed based on the exposure factor. Switch SW
₃ turns on when the shutter button is pressed down to the second stroke. The exposure control circuit 1 excites the electromagnetic release magnet Mg ₁ in response to the ON state of the switch SW ₃ , and activates the mechanical sequence of the camera (narrowing down of aperture, mirror up, shutter front curtain release, etc.). Then, the above calculation result is stored, for example, in conjunction with mirror up. Further, the exposure control circuit 1 excites the magnet Mg ₂ in response to, for example, turning on of the switch SW ₃ to prevent the shutter rear curtain from running. When the time corresponding to the proper shutter speed TV elapses from the time when the shutter front curtain travels, the magnet Mg ₂
Is demagnetized and the shutter rear curtain runs. Switch SW ₂
Transistor Q ₂ connected in parallel with, for example the switch SW ₃
Is turned on in response to ON, and turned off in response to the end of exposure control. As a result, the transistor Q ₁ is turned on during the exposure control, and the operation of the exposure control circuit 1 is guaranteed during this period.

The exposure control circuit 1 applies a voltage corresponding to the film sensitivity SV to a voltage follower (OP amplifier) A ₃₂ . The TTL photometric photodiode PD ₁₀ is connected between the positive and negative input terminals of the OP amplifier A ₃₃ . The reference power source E ₃₁ biases the positive input terminal of the OP amplifier A ₃₃ .
The logarithmic compression diode D ₁₀ forms a negative feedback loop of the OP amplifier A ₃₃ . The logarithmic expansion transistor Q ₃₄ converts the output voltage of the OP amplifier A ₃₃ into a current. OP amplifier A ₃₂
Output voltage biases the emitter of transistor Q ₃₄ . The integrating capacitor C ₁₀ is charged by the collector current of the transistor Q ₃₄ . The comparator A ₃₁ turns on the transistor Q ₃₂ when the charging voltage of the integrating capacitor C _{10 has} a predetermined relationship with the reference voltage E ₃₀ . Synchro switch SW ₃₁ having a terminal a, b is before traveling of the shutter front curtain selects the terminal a, it switched to the terminal b by the shutter fully opened time and again selects the terminal a in the running end of the shutter trailing curtain. Integrating capacitor C ₁₀ connected in parallel with the transistor Q ₃₆ is shorted integrating capacitor C ₁₀ becomes ON when the synchro switch SW ₃₁ selects the terminal a, synchro switch SW
_{When 31} is selecting the terminal b, it is turned off to allow the integration capacitor C ₁₀ to be charged. Circuit 50 surrounded by a dotted line
Constitutes a photometric circuit for generating a TTL light emission stop signal. The battery check circuit BC uses the transistors Q ₃ , Q ₃₇ , and Q when the voltage of the power source E ₁ matches the operation of the camera side circuit.
Turn on ₃₈ . These are OFF even when the switch SW ₁ and the transistor Q ₁ are OFF. The transistor Q ₃₅ is turned on in synchronization with the light emission of the electronic flash device as described later.
N. The photometric circuit 50 for generating a TTL light emission stop signal operates by receiving power from the power source E ₁ when the transistors Q ₃₅ and Q ₃₇ are ON. The transistor Q ₃₁ turns on when the transistor Q ₃₅ turns on. The switch SW ₅ is connected in parallel with the transistor Q ₃ , and the power switch SW ₁
It turns ON and OFF in the opposite phase to ON and OFF. The switch SW ₃₀ is turned on in conjunction with, for example, mirror up and turned off in conjunction with the end of exposure. The exposure control circuit 1 stores the TV at the proper shutter speed by turning on the switch SW ₃₀ ,
Release this with FF. The transistors Q ₃₀ and Q ₃₃ are turned on and off in synchronization with the turning on and off of the switch SW ₃₀ . The exposure control circuit 1 calculates a flash exposure factor AV-SV based on the exposure factors introduced from the variable resistors VR _{1 to} VR _3, and applies this to a voltage follower (OP amplifier) A ₃₀ . OP amplifier A ₃₀ outputs the input voltage when one or both of the transistors Q _30, Q ₃₁ is OFF, the transistors Q _30, Q ₃₁ can not both the output voltage when is ON. When both the transistors Q ₃₂ and Q ₃₃ are ON, the output voltage of the OP amplifier A ₃₀ becomes the voltage of the power supply line GND (logic L).

The connection terminal T ₁ is connected to the terminal b of the synchro switch SW ₃₁ . The connection terminal T ₂ is an OP amplifier A.
Connected to ₃₀ output terminals. The light emitting diode LED ₁ and the transistor Q ₃ are connected between the connection terminal T ₃ and the power supply line GND. The connection terminal T ₄ is connected to the power supply line GND. The base of the transistor Q ₃₅ is connected to the connection terminal T ₅ . The lens 60 is the optical system 6
1, a diaphragm 62 and a variable resistance V that works in conjunction with focusing
It has R ₁₀ . Variable resistors VR ₁ and VR ₂ and lens 60
There is an interlocking relationship as described above with. Connection terminal T
Electrical contacts T ₁₁ and T ₁₂ between the camera and the lens and a variable resistor VR ₁₀ are interposed between ₆ and the power supply line GND.

The exposure control circuit 1 is a light emitting diode LED ₁
A small current or a large current (which will be described later in detail) from the terminal T ₃ is switched to the flash photography mode by the voltage on the anode side, and the shutter time is the synchro time. Power switch SW ₁ is OFF, switch SW ₅ is ON
The shutter is mechanically controlled by the governor (not shown) instead of the exposure control circuit 1 when, and the shutter is electrically controlled by the exposure control circuit 1 when the power switch SW ₁ is ON and the switch SW ₅ is OFF. .

Next, the electronic flash device side circuit will be described with reference to FIG. The power supply E ₂ supplies power between the power supply line Vcc _{2 and} GND when the power switch SW ₆ is turned on. The booster circuit 8 boosts the voltage of the power source E ₂ to supply a high voltage power supply line VCM-GND.
Supply in the meantime. The main capacitor C ₃ is charged by the output of the booster circuit 8. The light emission control circuit 6 controls the start and stop of light emission of the flash discharge tube 5.

The start signal generating circuit 3 (for example, a one-shot multivibrator) is connected to the input terminal a connected to the terminal b of the synchro switch SW ₃₁ via the connection terminal T ₁ . When the synchro switch SW ₃₁ selects the terminal b, it has an output terminal b for outputting H (start output) for the maximum light emission time of the electronic flash device, for example, about 2 to 3 msec. The mode selection switch SW ₂₀ connected between the power supply line Vcc _{2 and} GND is turned on in the TTL dimming mode and turned off in the all light emission mode. Switch SW
₂₀ ON / OFF outputs (H when ON, L when OFF) are generated on the signal line P _0-10 . The output of the OP amplifier A ₃₀ of FIG. 1 is transmitted to the connection point P _0-11 and further to the base of the transistor Q ₂₂ via the connection terminal T ₂ . Variable resistance V
R ₄ is for setting the aperture value, and manually sets the aperture value AV set by the preset aperture ring of the lens. The variable resistor VR ₅ is for setting the film sensitivity, and manually sets the film sensitivity SV loaded in the camera. The constant current source I ₁ that generates a current proportional to the absolute temperature is variable resistors VR ₄ and VR ₅
Supply a constant current to the series circuit of. Therefore, the connection point P ₀
A voltage corresponding to the flash exposure factor AV-SV is generated at _-12 . Transistor Q ₂₁ is mode selection switch SW ₂₀
When turns on, it turns on. A bias current is applied to the base of the transistor Q ₂₀ via the connection terminal T ₅ . This bias current occurs when transistor Q ₂₁ is on and transistor Q ₃₁ (FIG. 1) is on.
Then, when the transistor Q ₂₀ turns on, the transistor Q ₃₅ (FIG. 1) also turns on. ON of transistor Q ₂₀ ,
The OFF output (L when ON, H when OFF) occurs at the connection point P _0-13 . AND gate G ₂ is a transistor Q
₂₂ ON / OFF outputs (H when ON, L when OFF), the start output of the terminal b of the start signal generating circuit 3 and the output of the signal line P _0-10 are input, and all 3 inputs are H.
When it becomes, H (first light emission stop signal) is output. A
The ND gate G ₃ receives the output of the signal line P _{0-10 and} the output of the connection point P as inputs. And the mode selection switch S
Outputs L when W ₂₀ is OFF (in all light emission mode) and / or when transistors Q ₂₀ and Q ₂₁ are ON (when transistors Q ₃₇ and Q _{38 in} FIG. 1 are ON), and also selects a mode. When the switch SW ₂₀ is ON (in the TTL dimming mode), and the transistors Q ₂₀ and Q ₂₁ are O.
When FF (transistors Q ₃₇ and Q _{38 in} FIG. 1 are OFF), H is output. The output of the AND gate G ₃ is called a mode inadequate signal.

The switches SW ₂₂ and SW ₂₃ are interlocked with each other and turned on and off in the same phase. Switch SW ₂₃ ON
Then, the discharge current flowing through the discharge tube 5 and the resistor R ₁₃ is integrated by the integrating circuit 7. The integrating circuit 7 monitors the light emission amount of the discharge tube 5 based on the integrated value, and when the light emission amount reaches a constant value (hereinafter referred to as divided light emission amount), the second light emission stop signal is generated. When the switches SW ₂₂ and SW ₂₃ are turned on, it is called a split light emission mode. The light emission control circuit 6 has a start output, the first
A light emission stop signal and a second light emission stop signal are input, and the discharge tube 5 is caused to start light emission in response to the start output, and the light emission is stopped in response to the first or second light emission stop signal.
The light emission amount until the light emission stop by the first light emission stop signal gives a proper exposure, but the light emission amount until the light emission stop by the second light emission stop signal does not necessarily give a proper exposure (details will be described later). The dimming success / failure detection circuit 30 receives the start output of the start signal generation circuit 3 and the first light emission stop signal of the AND gate G ₂ as input, and when the first light emission stop signal is not generated during the generation of the start output ( H (non-dimming display signal) is generated for a certain period of time when the electronic flash device does not provide proper exposure even if it emits maximum light.

The OP amplifier A ₁₀ has a positive input terminal connected to a connection point P.
Voltages _0-11 and P _0-12 are applied, and a variable resistor VR ₆ is connected between the output terminal and the negative input terminal. O
A constant current source I ₁₀ is connected between the negative input terminal of the P amplifier A ₁₀ and the power supply line GND. The constant current source I ₁₀ sinks a current proportional to absolute temperature. The switch SW ₂₁ has a signal line P.
It has a terminal a connected to _0-10 and a terminal b connected to the power supply line GND. When the switch SW ₂₁ selects the terminal a, the mode selection switch SW ₂₀ turns on.
In the (TTL dimming mode), the OP amplifier A ₁₀ receives the voltage at the connection point P _0-11 as input, and the switch SW ₂₀ is OFF.
If it is (all light emission mode), the OP amplifier A ₁₀ has a connection point P.
Input voltage _0-12 . Conversely, when the switch SW ₂₁ selects the terminal b, the OP amplifier A ₁₀ unconditionally connects to the connection point P _0-12.
The input voltage is. The variable resistor VR ₆ is arranged in the light emitting path of the discharge tube 5 and works in conjunction with an optical system 31 (for example, a Fresnel lens) that continuously changes the irradiation range of the emitted light.
The resistance value changes according to the irradiation range of the emitted light. The resistance value of the variable resistance value VR ₆ decreases as the irradiation range is narrowed (the guide number of the electronic flash device is increased),
It also increases as it is increased (the guide number is decreased). The output voltage of the OP amplifier A ₁₀ is obtained by adding the first correction voltage determined by the variable resistor VR ₆ to the voltages at the connection points P _0-11 and P _0-12 .

A Zener diode ZD ₁₀ and resistors R ₂₈ , R ₂₉ and R ₃₀ are connected in series between the high voltage power supply line VCM and GND. The Zener voltage of the Zener diode ZD ₁₀ is set to be equal to the lower limit value of the light emission voltage of the discharge tube 5, which is usually several tens of volts. Transistor Q
₂₃ and Q _{24 form} a current mirror circuit. When the charging voltage of the main capacitor C ₃ becomes higher than the Zener voltage, a current determined by the charging voltage and the resistance R ₂₀ is output to the collector of the transistor Q ₂₄ . OP amplifier A
The negative input terminal of ₁₁ is connected to the collector of the transistor Q ₂₄ , and the logarithmic compression diode D ₂₁ is connected between the output terminal of the OP amplifier A ₁₁ and the negative input terminal. Reference voltage source E
The voltage of ₂₀ is applied to the positive input terminal of the OP amplifier A ₁₁ .
Between the output terminal of the OP amplifier A ₁₁ and the power supply line GND, a temperature compensation diode D ₂₂ and a constant current suction source I ₁₁ that sucks a current proportional to absolute temperature are connected in series. A second correction voltage corresponding to the guide number of the electronic flash device that depends on the charging voltage of the main capacitor C ₃ is output to the connection point P _0-14 .

The positive input terminal of the OP amplifier A ₁₂ has a connection point P.
_0-14 , and the negative input terminal is connected to the output terminal of the OP amplifier A ₁₀ via the resistor R ₂₁ . Resistor R ₂₂ is OP
The negative feedback loop of the amplifier A ₁₂ is formed, and the resistance R ₂₃
And the constant current suction source I ₁₂ that sucks current proportional to absolute temperature is OP
It is connected in series between the output terminal of the amplifier A ₁₂ and the power supply line GND. At the connection point P _0-15 , the first near-limit voltage corresponding to the near-limit first closest shooting distance of the flash shooting distance determined by an electrical factor is output. A constant current source I ₁₃ that generates a current proportional to absolute temperature and a resistor R ₂₄ are connected in series between the power supply line Vcc _{2 and} GND via the switch SW ₂₂ described above. A third correction voltage corresponding to the divided light emission amount is output to the connection point P _0-16 . A constant current source I ₁₄ that absorbs a current proportional to absolute temperature and a variable resistor VR ₇ are connected in series between the power supply lines, and at a connection point P _0-17 thereof, a near limit of the flash photography distance determined by an optical factor. A second near-limit voltage corresponding to a recent shooting distance of 2 is generated. The variable resistance VR ₇ is linked to the optical system 31, and its resistance value decreases when the irradiation range is narrowed and increases when it is expanded.

OP amplifiers A ₁₃ , A ₁₄ , diodes D ₂₃ ,
D ₂₄ constitutes a minimum voltage selection circuit which receives the second correction voltage at the connection point P _{0-14 and} the third correction voltage at the connection point P _0-16 as inputs. As a result, the lower voltage of the second and third correction voltages is input to the positive input terminal of the OP amplifier A ₁₇ . That is, the switch SW _22, SW ₂₃ and the second or third correction voltage when the ON is also switch SW _22, SW ₂₃ and the second correction voltage when the OFF is inputted to the OP amplifier A _17.
The first correction voltage from the OP amplifier A ₁₀ is input to the negative input terminal of the OP amplifier A ₁₇ via the resistor R ₂₆ . The resistor R ₂₇ forms a negative feedback loop of the OP amplifier A ₁₇ . for that reason,
The OP amplifier A ₁₇ generates a far limit voltage corresponding to the far limit of the flash photographing distance based on the first correction voltage from the OP amplifier A ₁₀ and the second or third correction voltage from the minimum voltage selection circuit. The OP amplifier A ₁₇ and the resistors R ₂₆ and R _{27 form} an inverting amplifier circuit. The OP amplifiers A ₁₅ and A ₁₆ and the diodes D ₂₅ and D ₂₆ constitute a maximum voltage selection circuit having the first limit voltage at the connection point P _{0-15 and} the second limit voltage at the connection point P _0-17 as inputs. To do. As a result, the term voltage of the first and second limit voltages is input to the positive input terminal of the OP amplifier A ₁₈ .
The comparator A ₁₈ compares the far limit voltage from the OP amplifier A ₁₇ with the first or second near limit voltage from the maximum voltage selection circuit.

Zener diode ZD ₁₀ , voltage dividing resistor R ₂₈
~ R ₃₀ , the comparators A ₁₉ , A ₂₀ and the reference voltage source E ₂₂ constitute a charging voltage monitor circuit for the main capacitor C ₃ . The comparator A ₁₉ outputs H when the charging voltage of the main capacitor C ₃ exceeds the lower limit value of the flash light emission possible voltage. The comparator A ₂₀ outputs H when the charging voltage exceeds a voltage that enables light emission corresponding to the maximum light emission amount of the electronic flash device (hereinafter, this is referred to as charging completion).

Constant current source I for generating a current proportional to absolute temperature
₁₆ is connected between the power supply line Vcc ₂ and the connection terminal T ₆ . The comparator A ₂₁ receives the voltage of the connection terminal T _{6 and} the voltage of the reference voltage E ₂₁ as inputs. For example, constant current source I
_{When 16} is connected to the variable resistor VR ₁₀ (FIG. 1) via the connection terminal T ₆ , a voltage corresponding to the shooting distance is generated at the terminal T ₆ . However, if nothing is connected to the terminal T ₆ (when the electronic flash device is not equipped with the camera of FIG. 1), the voltage of the terminal T ₆ rises to the voltage of the power supply line Vcc ₂ . Therefore, if the reference voltage E ₂₁ is set to the upper limit value of the voltage change due to the change of the variable resistor VR ₁₀ , the comparator A when the voltage of the terminal T ₆ rises to the power supply line Vcc _2.
21 outputs L. The output of the comparator A ₂₁ acts to prevent erroneous display.

Constant current source I for generating a current proportional to absolute temperature
_15, resistors R _31, R ₃₂ and PTAT current the sinking constant current sink source I ₁₇ are connected in series to the power supply line Vcc ₂ and GND between. The comparator A ₂₂ has a comparison input selection function, and has a voltage at a connection point P _0-18 between the constant current source I ₁₅ and the resistor R ₃₁ .
The voltage at the connection point P _0-19 between the resistor R ₃₁ and the output terminal of the OP amplifier A ₁₇ and the voltage at the connection terminal T ₆ are applied. The comparator A ₂₃ has a comparison input selection function, and has a voltage at a connection point P _0-20 between the resistor R ₃₂ and the constant current source I ₁₇ , an output voltage (first or second near limit voltage) of the maximum voltage selection circuit, and a connection. The voltage at terminal T ₆ is applied. When the mode selection switch SW ₂₀ is ON, the positive input terminal of the comparator A ₂₂ has a connection point P.
The voltage _0-19 is input, and the negative input terminal of the comparator A ₂₃ receives the output voltage of the maximum voltage selection circuit. When the mode selection switch SW ₂₀ is off, the comparator A
The positive input terminal of ₂₂ receives the voltage at the connection point P _0-18 , and the negative input terminal of the comparator A ₂₃ receives the voltage at the connection point P _0-20 . The negative input terminal of the comparator A _{22 and} the positive input terminal of A ₂₃ are connected to the connection terminal T ₆ . Comparator A ₂₂ , A
Reference numeral ₂₃ is a window comparator.

The switch SW ₉ is turned on in the balanced illumination mode. A switch SW _{24, which} is connected in parallel with the switch SW ₉ , connects the electronic flash device and the camera via an extension cord so that the illumination position of the electronic flash device with respect to the subject can be arbitrarily selected, or when the additional flash is emitted. It is turned on when the electronic flash device is used for slave light emission.

The display section 40 has terminals P _{1 to} P ₁₃ . The terminal P ₁ is connected to the output terminal of the AND gate G ₃ , the terminal P ₂ is connected to the output terminal of the dimming success / failure detection circuit 30, and the terminal P ₃ is connected to the output terminal of the OP amplifier A ₁₇ . The output terminal of the comparator A ₁₈ is connected to the terminal P _4, and the output terminal of the maximum voltage selection circuit is connected to the terminal P ₅ .
The terminal P ₆ is connected to the power supply line Vcc ₂ via resistors R ₅₂ and R ₅₃ . The output terminals of the comparators A ₂₁ , A ₂₂ , and A ₂₃ are connected to the terminals P _{7 to} P ₉ , respectively. The output terminals of the comparators A ₂₀ and A ₁₉ are connected to the terminals P ₁₀ and P ₁₁ , respectively. The terminal P ₁₂ is connected to the signal line P _0-10 and receives ON and OFF signals of the mode selection switch. The terminal P ₁₃ is for turning on the switches SW ₉ and SW ₂₄ ,
OFF signal is input. The connection terminal T ₄ is a power supply line G
It is connected to ND. The transistor Q ₄₀ is a resistor R ₅₂ ,
It is turned on by the bias of R ₅₃ . Transistor Q ₄₀
The resistor R ₅₀ is connected in parallel to the series circuit of the resistor R ₅₁ and the resistor R ₅₁ . When the transistor Q ₄₀ is OFF, a resistance R ₅₀ is supplied, and a minute current which does not turn on the light emitting diode LED ₁ is supplied to the light emitting diode LED ₁ through the connection terminal T ₃ , and when the transistor Q ₄₀ is ON, the resistances R ₅₀ and R ₅₁ are supplied.
A lighting current for lighting the light emitting diode LED ₁ is supplied to the light emitting diode via the connection terminal T ₃ .

Next, the electrical characteristics when the electronic flash device is attached to the camera will be described in detail. (1) When the TTL light control mode: this time, the switch SW _22, SW ₂₃ is OFF, the mode selection switch SW ₂₀ is ON, the addition switch SW ₂₁ has selected the terminal a. At this time, if the release button of the camera is pressed up to the first stroke, the transistors Q ₃₀ and Q ₃₃ are turned off, so that the OP amplifier A ₃₀ outputs the output voltage VA shown below.
Outputs ₃₀ .

[0024]

[Equation 1] However, T: absolute temperature, k: Boltzmann constant, q: elementary charge of electron, α: constant switch SW ₂₀ is ON, so OP
The amplifier A ₁₀ has a voltage at the connection point P _0-11 , that is, the OP amplifier A _30.
The output voltage VA ₃₀ as the input. Therefore, OP amplifier A
₁₀ the output voltage VA ₁₀ (first correction voltage),

[0025]

[Equation 2] Is. However, γT is an added voltage by I ₁₀ and VR ₆ . The voltage V _C3 of the capacitor C ₃ is higher than the Zener voltage V _ZD10 of the Zener diode ZD ₁₀ , and (V _C3
-V _ZD10 ) >> V _BE . However, V _BE is the emitter-base voltage of the transistors Q _{23, 24} . The reverse saturation currents of the diodes D ₁ and D ₂ are equal, and the current of the constant current suction source I ₁₁ is i ₁₁ . The output voltage of the connection point P _0-14 (second correction voltage), i.e. OP amp positive input voltage of the positive input voltage VA _12in and OP amplifier A ₁₄ of A ₁₂ VA _14in

[0026]

[Equation 3] Is. However, εT is a reference voltage E ₂₀ proportional to the absolute temperature T.
, I _S is the reverse saturation current of diodes D ₁ and D ₂ which are equal to each other. Switch SW ₂₂ is OFF, so O
The output of P-Amp A ₁₃ is high enough and diode D ₃
Is reverse biased. Therefore, the input voltage VA _14in of the OP amplifier A ₁₄ is selected and becomes the positive input voltage VA _17in of the OP amplifier A ₁₇ . Output voltage VA of OP amplifier A _{17
17 out}

[0027]

[Equation 4] From the expressions (2) to (4), the output voltage of the OP amplifier A ₁₇ is

[0028]

[Equation 5] Becomes If R ₂₆ = R ₂₇ , then equation (5) becomes

[Equation 6] Is. This output voltage VA _17out is TTL as described later.
Corresponds to the farthest possible shooting distance in dimming mode. The farthest dimmable photographing distance depends on the output voltage (first correction voltage) of the OP amplifier A ₁₀ having the maximum light emission amount correction information depending on the adjustment of the flash irradiation range and the charging voltage of the main capacitor C ₃ . Connection point P with maximum light emission correction information
Since it is calculated in consideration of the output voltage of _0-14 (second correction voltage), it is corrected according to the adjustment of the flash irradiation range and the charging voltage of the main capacitor. Therefore, it is possible to give proper exposure to a subject closer than the farthest shooting distance at which light control is possible by light control (emission amount control).

(2) The switches SW ₂₂ and SW ₂₃ are OF
F, the mode selection switch SW ₂₀ is turned off, and the switch SW ₂₁ selects the terminal a (all light emission modes): At this time, the OP amplifier A ₁₀ outputs the output voltage V _{0-at the} connection point P _0-12. Enter ₁₂ This output voltage is a variable resistor VR ₄ ,
It is equal to the output voltage VA ₃₀ of the OP amplifier A ₃₀ by VR ₅ and the constant current source I _1. Therefore, each output voltage is represented in the same manner as shown in the equations (2) to (6).
However, since the mode changeover switch SW ₂₀ is off, the emission discharge tube 5 emits all light (the light emission amount is not controlled). _{Therefore, the} output voltage VA _17out obtained by the equation (6) is properly exposed in the all light emission mode. Will correspond to the only shooting distance that can be obtained.

(3) Switches SW ₂₂ and SW ₂₃ are ON,
When the mode selection switch SW ₂₀ is turned on and the switch SW ₂₁ is selected at the terminal a, TTL dimming and divided light emission mode: At this time, the constant current source I ₁₃ is connected to the connection point P _0-16.
And the voltage determined by the resistor R ₂₄ , that is, the input voltage VA _13in (third correction voltage) of the OP amplifier A ₁₃ is

[Equation 7] Is. However, η ₁ is a constant determined by the resistance R ₂₁ . On the other hand, since the OP amplifier A ₁₄ is input the input voltage VA _14in indicated by (3), the input voltage VA _13In and VA
Output voltage _VA 17out of the OP amplifier A ₁₇ in accordance with the magnitude of _14in
Changes.

[0031] When _VA 13in <VA _14in; because the minimum voltage selection circuit at this time selects the VA _13In, the output voltage VA _17Out the OP amplifier _{A 17 (2), (4} ), from (7)

[Equation 8] Becomes Since the input voltage VA _13In is information of the maximum light emission amount corresponding to the divided light-emitting amount, the output voltage VA _17Out the TTL
It represents the farthest shooting distance at which TTL light control is possible in the light control mode and the split light emission mode. Note that η ₁ is selected according to the divided light emission amount.

[0032] When _VA 13in> VA _14in; because the minimum voltage selection circuit at this time selects the VA _14in, the output voltage VA _17Out the OP amplifier A ₁₇ is in the same manner as (6). This is an operation when the charging voltage of the main capacitor C ₃ is not charged until the divided light emission amount is satisfied, but the lower limit of the light emission possible voltage is exceeded. Therefore, the output voltage VA _1
7out is maximum light emission amount correction information (added to the second correction voltage) that depends on the charging voltage of the main capacitor C ₃ , and maximum light emission amount correction information (added to the first correction voltage) that depends on adjustment of the flash irradiation range. Is corrected according to (1).
At this time, continuous flash photography is impossible. This is because the energy of the main capacitor is consumed by one light emission.

(4) Switches SW ₂₂ and SW ₂₃ are ON,
When the mode selection switch SW ₂₀ is turned off and the switch SW ₂₁ selects the terminal a (all light emission, divided light emission mode): At this time, the OP amplifier A ₁₀ has the connection point P _0-12.
The output voltage P _0-12 (= VA ₃₀ ) of is input. Therefore,
Each output voltage is represented in the same manner as shown in the equations (2) to (8). However, the mode selection switch SW ₂₀ turns off.
Since it is FF, TTL dimming is not performed. Therefore, VA
_13In <VA when the _14in (8) expression of the output voltage VA _17Out
Corresponds to the only shooting distance (appropriate shooting distance) at which proper exposure is obtained when light is emitted for the divided light emission amount. Further, when the _VA 13in> VA _14in output voltage VA _17Out is where determined by the charging voltage and flash light irradiation range of the main capacitor, proper exposure is obtained. It corresponds to the only shooting distance (appropriate shooting distance).

(5) When the switch SW ₂₁ selects the terminal b: At this time, the OP amplifier A ₁₀ unconditionally inputs the output voltage V _0-12 (= VA ₃₀ ) of the connection point P _0-12. since the, (2), the photographing distance information described in (4) is output to the OP amplifier a _{1 7 out.}

(6) The electrical characteristics (1) to (5) described above are based on the assumption that the light emission amount can be continuously changed within the range of zero to the maximum light emission amount. The minimum amount of light that can be controlled is not finite but finite. Therefore, proper exposure may not be obtained at a close range. The measures against this will be described below.

Now, the voltage VR ₂₃ generated at the connection point P _0-15
Is

[Equation 9] Is. However, δ is a constant determined by I ₁₁ and R ₂₃ . Therefore, the input voltage VA _15in of the OP amplifier A ₁₅ is

[0037]

[Equation 10] Is. From the equations (2), (3), (9) and (10), the input voltage V is

[Equation 11] Becomes

Here, in order to correspond to the equation (6), R ₂₁ =
If R ₂₂

[Equation 12]

Comparing equations (6) and (12), the input voltage VA _15in is level-shifted to a lower voltage than the output voltage VA _17out of the OP amplifier A ₁₇ by δ. As a result, the input voltage VA _15in indicates the first closest shooting distance due to the electrical factor. Δ in equation (12)
Is a fixed minimum light amount determined by the operation delay of the light emission control circuit 6, the residual light of the discharge tube from the time when the first and second light emission stop signals are generated until the light emission is actually stopped, and the main capacitor C.
It is the ratio to the maximum light amount when all the stored energy of ₃ is emitted. Usually, the guide number GN _MAX of the maximum light emission amount
The guide number GN _{MIN with the} minimum light intensity is 1/6 to 1
It is about / 10. And the ratio is relatively constant with respect to the change of the charging voltage VC ₃ of the main capacitor C ₃ ,
On the other hand, the maximum amount of light emission corresponding to the guide number GN _MAX depends on the charging voltage VC ₃ of the main capacitor C ₃ .

On the other hand, the input voltage VA of the OP amplifier A _{16
16 in} (independent of the flash exposure factor) is set by the variable resistor VR ₇ linked to the optical system 31, and is a voltage corresponding to the second latest photographing distance determined by the optical characteristics as described above, and VA It is represented by _16in = θT. θ is a constant determined by the constant current source I ₁₄ and the variable resistor VR ₇ .
The actual closest distance limit is determined by the longer one of the first and second closest shooting distances, whichever is longer, which is determined by an electrical factor, a photographic factor, or an optical factor.
The maximum voltage selection circuit _{composed of} the OP amplifiers A ₁₅ and A ₁₆ selects the larger one of the input voltages VA _15in and VA _16in , that is, the longer one of the voltages corresponding to the closest photographing distance.

The above is the electrical characteristics. Next, the relationship between the shooting distance and the voltage will be described. The guide number GN corresponding to the light emission amount of the electronic flash device is

[Equation 13] Is. However, K is a constant determined by the charging voltage of the main capacitor, its capacity, the luminous efficiency of the discharge tube, and the like. The constant K is

[Equation 14] Is. Here, φ is a coefficient determined by the range (light-condensing characteristic) of the light irradiated by the optical system 31 on the subject, μ is a conversion constant when calculating the guide number, and I (t) is the irradiation light amount.

Since I (t) is proportional to the electric energy discharged in the discharge tube,

[Equation 15] Becomes Here, ν is a coefficient for converting electric energy of the flash discharge tube into light energy, C is the capacitance value of the main capacitor, V ₁ is the charging voltage of the main capacitor at the start of flash discharge, and V ₂ is at the end of flash discharge. It is the residual voltage of the main capacitor.

From equations (14) and (15)

[Equation 16] On the other hand, when the guide number GN is given, the relationship between the aperture value AV and the shooting distance D (m) for obtaining the proper exposure is

[Equation 17] Therefore, from equations (13) and (16)

[Equation 18] Becomes Substituting equation (16) for K in equation (18),

[Formula 19]

Next, converting both sides of the equation (19) into logarithmic equations,

[Equation 20] Becomes

Now, comparing equations (6) and (20), equation (6)

[Equation 21] Is the slope term of the output voltage VA _15out ,

[Equation 22] Is a constant term (level shift term),

[Equation 23] Is a variable term, and similarly in (20),

[Equation 24]

[Equation 25] Is the first variable term, and SV-AV is the second variable term. That is, the expressions (6) and (20) are similar to each other. Therefore, if the slope term, the constant term, and the first and second variable terms of the expressions (6) and (20) are associated with each other, the output voltage VA _15out changes in proportion to the logarithm of the shooting distance. Hereinafter, similarly, the expressions (8) and (12) also correspond to the logarithm of the distance. Further, the input voltage VA _16in of the OP amplifier A ₁₆ directly corresponds to the logarithm of the second recent photographing distance.

The light emission and the light emission stop operation according to FIGS. 1 and 2 will be described below. (A) Operation in TTL dimming mode: The mode selection switch SW ₂₀ is ON, and the switches SW ₂₂ and SW ₂₃ are OFF. Also, the switch SW ₅ is off. Now, when you press the release button to the first stroke, the transistor Q
₁ turns on. At this time, since the switch SW ₃₀ is off, the transistors Q ₃₀ and Q ₃₃ are off, and therefore the flash exposure factor SV-AV from the OP amplifier A ₃₀ exposure control circuit 1 is output. This flash exposure factor is transmitted to the connection point P _0-11 via the connection terminal T ₂ . The transistor Q ₂₂ does not turn on depending on the flash exposure factor. On the other hand, when the mode selection switch SW ₂₀ is ON, the transistors Q ₃ , Q
_{When 37} and Q ₃₈ are ON (when the voltage of the power source E ₁ is normal), the transistors Q ₂₀ , Q ₂₁ and Q ₃₅ are ON. Therefore, the output of the AND gate G ₃ becomes L and the transistor Q ₃₁ becomes ON.

By the way, when the electronic flash device is attached to the camera and the power switches SW ₁ and SW ₆ are turned on, the light emitting diode LED ₁ is connected to the power source E via the resistor R ₅₀ and the connection terminal T _3.
A small electric current is supplied from. Therefore, the exposure control circuit 1 opens and closes the shutter at the sync time. Then, when the charging of the main capacitor C ₃ is completed, the transistor Q ₄₀ is turned on, so that the light emitting diode LED ₁ is turned on.

Now, when the release button is pushed to the second stroke, the mechanical sequence of the camera is started and the switch SW ₃₀ is first turned on. Then, the transistors Q ₃₀ , Q
_{Since 33} is turned on, the OP amplifier A ₃₀ stops the generation of the flash exposure factor. Next, when the shutter is fully opened, the synchro switch SW ₃₁ is switched from the terminal a to the terminal b. Therefore, the activation signal generation circuit 3 to which L is applied via the connection terminal T ₁ generates an activation signal at the output terminal b. The light emission control circuit 6 makes the discharge tube 5 emit light in response to the activation signal. At the same time, the transistor Q ₃₆ is turned off, so that the integrating capacitor C ₁₀ is charged according to the reflected light from the subject. When the charging voltage of the integrating capacitor C ₁₀ becomes lower than the voltage of the reference power source E ₃₀ , the comparator A ₃₁ generates H and turns on the transistor Q ₃₂ . Thus, the base of the transistor Q ₂₂ is the terminal T _2, the transistor Q _32, from being connected to the feed line GND via the Q ₃₃ transistor Q ₂₂ is turned ON. Therefore, the AND gate G ₂ generates H (first light emission stop signal) and applies it to the light emission control circuit 6. Therefore, the light emission of the discharge tube 5 is stopped. When the photographing is completed, the transistor Q ₃₆ is turned on to short-circuit the integrating capacitor C ₁₀ .

(B) Operation in all light emission mode: The mode selection switch SW ₂₀ is turned off, and the switches SW ₂₂ and SW ₂₃
Is off. The switch SW _{5 is} also off. Now, when the release button is pushed all the way to the first stroke, the switch SW ₂₀ is turned off to turn on the transistors Q ₂₀ and Q _21.
Is turned off, the transistor Q ₃₅ is turned off. Therefore, the flash exposure factor is transmitted from the OP amplifier A ₃₀ to the connection point P _0-11 via the connection terminal T ₂ . At this time, the transistor Q ₂₂ is off. Next, press the release button
When pushed to the stroke, the switch SW ₃₀ is turned on, so that the OP amplifier A ₃₀ stops the generation of the flash exposure factor as described above. Then, the synchro switch SW ₃₁ is connected to the terminal b.
When is selected, the activation signal generation circuit 3 generates an activation signal, and the discharge tube 5 starts emitting light. On the other hand, the transistor Q ₃₅
Is turned off, the TTL light emission amount detection circuit 50 does not operate, so the transistors Q ₃₂ and Q ₂₂ do not turn on.
The gate G ₂ does not generate H (first light emission stop signal). Therefore, the discharge tube 5 emits all light corresponding to the nominal guide number and terminates light emission.

(C) Operation in TTL dimming divided light emission mode: mode selection switch SW ₂₀ , switch SW ₂₂ , S
W ₂₃ is on and switch SW ₅ is off.
In this mode, press the release button to the first stroke and the second stroke, and perform the dimming operation after that.
The operation is exactly the same as that in the L dimming mode, but the following operation is added to this. That is, when the discharge tube 5 starts emitting light, the discharge current at that time is integrated by the integrating circuit 7, and as a result, it is detected that the divided light emission amount is emitted,
The second light emission stop signal is applied to the light emission control circuit 6. Therefore, the light emission control circuit 6 stops the light emission of the discharge tube 5 in response to the first light emission stop signal or the second light emission stop signal, whichever is earlier. Proper exposure is obtained if the light emission is stopped by the first light emission stop signal, but proper exposure is not always obtained by the light emission stop by the second light emission stop signal (maybe improper). This is because the second light emission stop signal is generated not on the basis of whether or not the subject illumination is appropriate, but on the basis of the light emission amount for convenience of the divided light emission amount.

(D) Operation in full light emission / divided light emission mode: At this time, the mode selection switch SW ₂₀ is turned off.
However, the switches SW ₂₂ and SW ₂₃ are turned on. The switch SW ₅ is off. The operation in this mode is the same as the operation in the TTL dimming / divided emission mode described above except that the first light emission stop signal from the AND gate G ₂ is not generated because the switch SW ₂₀ is off. Therefore, only the divided light emission amount is emitted according to the second light emission stop signal. The above-described operations (3-a) and (4-a) are convenient when the motor drive device is mounted on the camera and continuous flash photography is performed. That is, if a subject whose shooting distance is constant (relatively short distance) is selected, proper exposure can be obtained even with the divided light emission amount. On the other hand, the main capacitor C ₃ at the time of completion of charging stores energy enough to cover several times of light emission for such a subject, so continuous flash photography is possible.

FIG. 3 shows a first embodiment circuit example of the display section 40, and FIG. 4 is an external view thereof. In FIG. 3, the reference voltage source E ₄₀ generates a voltage proportional to absolute temperature. The plurality of voltage dividing resistors R _{40 to} R ₄₅ generate a plurality of reference voltages having the same voltage difference as the reference voltage. First comparator group CP
_{1-1 to} CP _1-5 use the output voltage (the farthest shooting distance or the only shooting distance) of the OP amplifier A ₁₇ as a comparison input via the terminal P ₃ . The second comparator groups CP _{2-1 to} CP _2-4 use the output voltage (first or second closest photographing distance) of the maximum voltage selection circuit as a comparison input via the terminal P ₅ . When the mode selection switch SW ₂₀ is ON and the terminal P ₁₂ is H (TTL
1st in dimming mode and TTL dimming / divided emission mode)
NAND gate groups G _{1-1 to} G _1-4 output H,
AND gate groups G _{3-1 to} G _3-4 respectively correspond to the logical output of the first comparator group and the second NAND gate group G.
A logic output determined by the logic outputs of _{2-1 to} G _2-4 is generated. That is, in each of the first comparator groups CP _{1-1 to} CP _1-5 , the voltage according to the farthest shooting distance output from the OP amplifier A ₁₇ when the mode selection switch SW ₂₀ is ON is referred to. If it is higher than the voltage, it outputs H, and the second
Each of the comparator groups CP _{2-1 to} CP _2-4 outputs H if the input voltage of the terminal P ₅ according to the first or second closest photographing distance is higher than the respective reference voltage. The second
The NAND gate groups G _{2-1 to} G _2-4 of FIG. 2 output H when the output of the corresponding second comparator group is L, and conversely output L when the output of the corresponding second comparator group is H. Therefore, the switch SW ₂₀
When ON, the AND gates G _{3-1 to} G _3-4 correspond to the shooting distance between the farthest shooting distance and the closest shooting distance (collectively the first and second closest shooting distances). Is output. Next, when the mode selection switch SW ₂₀ is OFF, the second NAND gate groups G _{2-1 to} G _2-4 output H,
In addition, the terminal P ₃ has a full-emission mode or a full-emission mode.
OP amp A ₁₇ for shooting distance in split flash mode
The output voltage of is input. Then, the comparator that receives the reference voltage higher than the output voltage of the OP amplifier A ₁₇ at this time outputs L, and conversely, the comparator that receives the lower reference voltage outputs H. Therefore, for example, the comparators CP _1-1 and CP _1-2 output L, and the comparator C
If P _{1-3 to} CP _1-5 output H, the first N
Of the AND gate group, only the NAND gate G _1-2 outputs H, and since the comparator CP _1-3 outputs H, only the AND gate G _3-2 outputs H. As described above, when the mode selection switch SW ₂₀ is OFF, the AND gate corresponding to the only shooting distance for obtaining proper exposure is at H level.
Is output. The light emitting diodes L _{2 to} L _n-1 are the corresponding ANs.
It lights up with the H output of the D gate. The pulse generator 70 is OR
When the output of the gate G ₁₅ is L, H is output, and when it turns to H, H and L are alternately output.

The display operation will be described below. (I) TTL dimming mode or TTL dimming / divided emission mode
Mode: At this time, the camera of Fig. 1 and the electronic flash of Fig. 2
The device is connected. Mode selection switch SW₂₀Is O
N and AND gate G₃Apply H to one input terminal
But transistor Q₃₅, Q₃₇, Q₃₈And transistor Q
₂₀, Q_{twenty one}Is ON (power supply E₁If there is enough voltage
), AND gate G₃Is L the terminal P of the display₁Apply to
It OP amplifier A_TenIs the connection point P_0-11Input voltage
It Terminal P₂Is L from the dimming success / failure detection circuit 30 before light emission.
Is being applied. Mode selection switch SW₂₀Is ON
Therefore, comparator A_{twenty two}Is the connection point P_0-19Voltage (minimum voltage
Output of the pressure selection circuit)_{twenty three}
Is the output of the maximum voltage selection circuit. TTL dimming mode
Mode switch SW₂₀ON by turning on the terminal
P₁₂Becomes H. In addition, switch SW₉, SW_{twenty four}Is OFF
At terminal P₁₃Is L. Assuming the above, the conditions
The following operations are performed according to・Farthest shooting distance> Lens setting distance> Recent shooting distance
You: First, the charging voltage of the main capacitor C can emit light
Comparator A when the lower limit is exceeded₁₉Output (terminal P₁₁of
Input) turns to H, but comparator A₂₀Output (terminal
P_TenInput) remains L (main capacitor C₃
Is not yet charged). Therefore, the farthest shooting distance> lens
If the condition of setting distance> recent shooting distance is satisfied,
Data A₁₈Output (terminal P_FourInput) becomes L. Also,
Mode selection switch SW₂₀Is ON, comparator A_{twenty two}
Is the connection point P_0-19Voltage [first and second correction voltage (and required
Corresponds to the farthest shooting distance determined by the third correction voltage)
Input voltage] and input to comparator A_{twenty three}Is the maximum voltage selection
Output voltage of the selection circuit (depending on the first or second limit voltage
The voltage that corresponds to the recent shooting distance is set as input
It This comparator A_{twenty two}, A_{twenty three}Is the variable resistance VR_TenEdge of
Since the child voltage is used as a common input, under the above conditions
Is comparator A_{twenty three}Output (terminal P₉Input) are both H
Becomes On the other hand, the variable resistance VR_TenTerminal voltage (comparator
Type A_{twenty one}Negative input voltage) is the reference voltage E_{twenty one}Lower voltage than
Since it changes in the range, comparator A_{twenty one}Output (terminal P
₇Input) becomes H.

Therefore, the gates G ₁₁ , G ₁₂ , and G ₁₈ output H, and the gates G ₁₀ , G _{13 to} G ₁₇ output L. NA
When the ND gate G ₁₀ outputs L, the light emitting diode corresponding to the shooting distance between the farthest shooting distance and the closest shooting distance among the light emitting diodes L _{2 to} L _n is turned on, and the TT is turned on.
The shooting distance at which the proper exposure is obtained by L dimming is displayed. On the other hand, since the NAND gate G ₁₂ is H, the light emitting diodes LED ₉ and LED ₁₀ do not light up. Further, since the NAND gate G ₁₈ outputs H, the transistor Q ₄₀ is OF
It becomes F. On the other hand, when the power switch SW ₆ is turned on, a minute current is supplied to the light emitting diode LED ₁ of the camera through the terminal T _{3, so} that the shutter time of the camera is set to the sync time.

Next, when charging of the main capacitor C ₃ is completed, the output of the comparator A ₂₀ (input of the terminal P ₁₀ ) shifts to H, so that the outputs of the NAND gates G ₁₂ and G ₁₈ shift to H. Therefore, the light emitting diodes LED ₁₀ and LED ₁₁ are turned on to indicate that the lens set distance set by the lens 60 satisfies the above condition. At this time although the main capacitor C ₃ is the farthest object distance because they completed charging is growing, the number of lit light emitting diode L ₂ ~L _n by the action of the second correction voltage is increased by that amount . A
When the ND gate G ₁₈ outputs L, the transistor Q ₄₀ becomes O.
Since it becomes N, the light emitting diode LED _{1 of the} camera lights up to indicate the completion of charging of the main capacitor C ₃ .

When the lens 60 does not have the variable resistor VR ₁₀ , the connection terminal T ₆ is opened, and the output of the comparator A ₂₁ (input of the terminal P ₇ ) shifts to L.
The NAND gate G ₁₂ and the AND gate G ₁₄ output L regardless of other inputs. Thus, since this time does not light emitting diodes LED _10, LED ₁₁ is, may be set the distance of the lens within the photographing distance is displayed by the light emitting diode L ₂ ~L _n. When the farthest shooting distance <the closest shooting distance : At this time, one of the output of the comparator A ₂₂ (input of the terminal P ₈ ) and the output of the comparator A ₂₃ (input of the terminal P ₉ ) becomes H, and the other is L Becomes Therefore, assuming that the main capacitor C ₃ is charged only to the extent that it exceeds the lower limit value of the light-emission voltage, the NAND gate G ₁₀ outputs L and the NAND gate G ₁₂ outputs H, so at this time the light-emitting diode is emitted. Only the shooting distance display by L _{2 to} L _n is performed.

Next, when charging of the main capacitor C ₃ is completed, the output of the NAND gate G ₁₂ shifts to L, so that one of the light emitting diodes LED ₁₀ and LED ₁₁ is turned on. On the other hand, since the NAND gate G ₁₃ outputs H, the OR gate G ₁₅ outputs H when the terminal P ₁₀ shifts to H due to completion of charging. As a result, the pulse generator 70
, The NAND gate G ₁₈ alternately outputs H and L. Therefore, the light emitting diode LED _{1 of the} camera blinks to indicate that charging of the main capacitor C ₃ is complete and that the lens distance setting is inappropriate.
Therefore, the photographer uses both light emitting diodes LED ₁₀ and LED ₁₁
The focusing ring of the lens 60 is operated so that lights up. When both the light emitting diodes LED ₁₀ and LED ₁₁ are turned on, the outputs of the gates G _{13 to} G ₁₅ are turned to L, so that the light emitting diode LED _{1 of the} camera is turned on to indicate that flash photography is possible.

When the farthest shooting distance <the closest shooting distance : This is due to an inappropriate combination of aperture value and film sensitivity, insufficient charging of the main capacitor C ₃ , and improper setting of the optical system 31. Therefore, the output of the comparator A ₁₈ (terminal P
₄ input) becomes H. Therefore, the output of the NOR gate G ₁₁ becomes L, and the outputs of the NAND gates G ₁₀ , G ₁₂ and G ₁₈ become H. Therefore, the light emitting diode L ₁ is turned on, and the light emitting diodes L _{2 to} L _n , LED ₁₀ , LED ₁₁ , and LED ₁ are turned off. This state continues unless all the above causes are eliminated.

When the photographing distance is set according to the above-described display operation or the cause of the defect is removed and the preparation for the flash photographing is completed and the camera is released, the automatic light emission amount control by TTL photometry is performed. On the other hand, when the synchro contact SW ₃₁ is switched to the terminal b, the transistor Q ₂₀ is turned off, so that the output of the AND gate G ₃ (input of the terminal P ₁ ) shifts to H. Then, the NOR gate G ₁₁ outputs L and the NAND gate G ₁₀ outputs H, so that the light emitting diodes L _{2 to} L _n are turned off. Further, the NAND gate G ₁₈ is a NOR gate G
_Since the output of ₁₁ outputs H during L, the light emitting diode LED _{1 of the} camera is turned off during this period. In addition, when the charging voltage of the main capacitor drops due to the flash emission, terminal P ₁₀ goes to L
Then, the light emitting diodes LED ₁₀ and LED ₁₁ are also turned off. On the other hand, the OR gate G ₁₅ outputs H to operate the pulse generator 70, while the NAND gate G ₁₈ outputs H while the output of the NOR gate G ₁₁ is L.

Now, when the amount of light emission reaches a predetermined value, the light emission of the discharge tube 5 is stopped by the first light emission stop signal of the AND gate G ₂ . In this case, the output of the dimming success / failure detection circuit 30 remains L. Therefore, if the synchro switch SW ₃₁ is switched to the terminal a after the flash photographing is finished, the above-mentioned display operation is repeated. On the contrary, if the light emission amount does not reach the predetermined value, the dimming success / failure detection circuit 30 outputs H for a certain period of time, and the AND gate G ₁₆ outputs H. Therefore, after the flash photography is completed, the synchro switch SW ₃₁ is switched to the terminal a and the NOR gate G
_{When 11} outputs H, the NAND gate G ₁₈ alternately outputs H and L, causing the light emitting diode LED _{1 of the} camera to blink. This causes the dimming failure to be displayed.

If the flash exposure factor SV-AV is not transmitted to the electronic flash device for some reason when the camera of FIGS. 1 and 2 is connected to the electronic flash device, the switch SW ₂₁ is turned on. If you switch to terminal b, OP amplifier A ₁₀
Inputs the exposure factor for flash generated at the connection point P _0-12 .
Therefore, if the aperture value and the film sensitivity on the camera side are manually set by the variable resistors VR ₄ and VR ₅ , the above display operation is performed.

(Ii) In the full-emission mode or the full-emission / division-emission mode: At this time, since the camera of FIG. 1 and the electronic flash device of FIG. 2 are connected, the terminal P ₇ is at H. Mode selection switch SW ₂₀ is off and AND gate G
The output of ₃ (input of the terminal P ₁ ) becomes L. OP amplifier A ₁₀
Inputs the voltage at the connection point P _0-12 . L is constantly applied to the terminal P ₂ from the dimming success / failure detection circuit 30. Switch SW ₂₀
When P is turned off, the terminal P ₁₂ becomes L. Further, since the mode selection switch SW ₂₀ is OFF, the comparator A ₂₂ receives the voltage at the connection point P _0-18 , and the comparator A ₂₃ receives the voltage at the connection point P _0-20 . In addition, switches SW ₉ and SW ₂₄
Is OFF and terminal P ₁₃ is L. When the terminal P ₁₂ is at L, only one of the light emitting diodes L _{2 to} L _n is turned on according to the only shooting distance (hereinafter referred to as the appropriate shooting distance) at which proper exposure is obtained. The voltage corresponding to this appropriate shooting distance is the input voltage of the terminal P ₃ as described above.

• Appropriate shooting distance> Recent shooting distance : At this time, the output of the comparator A ₁₈ (input of the terminal P ₄ ) is L
Therefore, the NOR gate G ₁₁ outputs H and does not turn on the light emitting diode L ₁ . Now, when the charging voltage of the main capacitor exceeds the lower limit value of the light emission possible voltage, the output of the comparator A ₁₉ (input of the terminal P ₁₁ ) becomes H, while the output of the comparator A ₂₀ (input of the terminal P ₁₀ ) becomes L. There is. At this time, since the NAND gate G ₁₀ outputs L, any one of the light emitting diodes L _{2 to} L _n lights up. Of course, the input voltage of the terminal P ₃ takes into account the information of the first and second correction voltages (and also the third correction voltage if necessary). However, since the output of the NAND gate G ₁₂ is still H, the light emitting diodes LED ₁₀ and LED ₁₁ do not light.
At this time, if necessary, flash photography may be performed by matching the appropriate photography distance displayed by the light emitting diodes L _{2 to} L _{n with the} photography distance of the lens setting.

Next, when the charging of the main capacitor is completed, the NAND gate G ₁₂ outputs L. On the other hand, the comparators A ₂₂ and A ₂₃ have the terminal voltage of the variable resistor VR ₁₀ as a common input and the voltages at the connection points P _0-18 and P _0-20 as inputs. This connection point voltage has a predetermined dead band width centered on the voltage corresponding to the proper shooting distance and is set to the comparators A ₂₂ , A _23.
I'm giving in between. Therefore, the lens setting distance (variable resistance V
When the terminal voltage of R ₁₀ ) is within the dead band width, the outputs of the comparators A ₂₂ and A ₂₃ (the inputs of the terminals P ₈ and P ₉ ) both become H, so that the light emitting diodes LED ₁₀ and LED ₁₁ light up. At this time, since the NAND gate G ₁₃ outputs L, the NAND gate G ₁₈ outputs L and turns on the light emitting diode LED _{1 of the} camera. On the other hand, when the lens set distance (terminal voltage of the variable resistor VR ₁₀ ) is outside the dead zone width, the light emitting diode LE is selected depending on whether the lens set distance is too far or too short.
Either D ₁₀ or LED ₁₁ lights up. Then NA
Since the ND gate G ₁₃ , the AND gate G ₁₄ , and the OR gate G ₁₅ output H, the pulse generator 70 operates. Therefore, the NAND gate G ₁₈ alternately outputs H and L to blink the light emitting diode LED _{1 of the} camera. As a result, it is displayed that the lens set distance does not match the proper shooting distance.

If the lens 60 is not provided with the variable resistor VR ₁₀ , the output of the comparator A ₂₁ (terminal P
₇ input) is L, so light emitting diode LED ₁₀ , L
ED ₁₁ goes out. At this time, the light emitting diode L ₂
The proper shooting distance displayed by L _n is matched with the lens setting distance. The light emitting diode LED ₁ of the camera lights up when the charging of the main capacitor is completed.

Proper shooting distance <Recent shooting distance : At this time, light emitting diodes L _{2 to} L _n , LED ₁₀ , LED
₁₁ , LED ₁ goes off, and light emitting diode L ₁ goes on.

(Iii) In the bounce illumination or the additional light emission mode: At this time, the states of the switches SW ₉ and SW ₂₄ are set to OF.
When it turns from F to ON, the NAND gates G ₁₀ and G _{12 become} H.
Is output, the light emitting diodes L _{2 to} L _n , the LED ₁₀ ,
The display by LED ₁₁ is not performed. However, if the farthest shooting distance <the closest shooting distance or the proper shooting distance <the latest shooting distance when the main capacitor C ₃ is charged and the NOR gate G ₁₁ outputs L, the light emitting diode L ₁ is turned on. Is displayed. When the NOR gate G ₁₁ is H, the completion of charging of the main capacitor causes the NAND gate G ₁₈ to output L to turn on the light emitting diode LED _{1 of the} camera.

(Iv) When the operational relationship between the camera and the electronic flash device is inconsistent: Typically, the electronic flash device in FIG.
An example is when the camera is mounted on a camera that does not have the TL light control function and the mode selection switch SW ₂₀ is ON. At this time, since the output of the AND gate G ₃ (input of the terminal P ₁ ) becomes H, the NOR gate G ₁₁ outputs L. for that reason,
Since the NAND gates G ₁₀ , G ₁₂ , and G ₁₈ output H,
Light emitting diodes L _{2 to} L _n , LED ₁ , LED ₁₀ , LED
₁₁ turns off. In this operation, the transistor Q ₁ is OF
This also occurs when the switch SW ₁ is turned off and the switch SW ₅ is turned on when the camera is in the F state or when the electronic flash device is connected to the camera shown in FIGS.

FIG. 4 shows an external appearance example of the display portion of the electronic flash device. In FIG. 4, the light emitting diode L ₁ is NG
The symbol (non-good) is attached to the light emitting diode L.
Shooting distance scale is attached to the ₂ ~L _n. The light emitting diodes LED ₁₀ and LED ₁₁ have an arrow shape, and the arrow direction of each light emitting diode corresponds to the rotation direction of the focusing ring of the lens 60. The knob 71 is for setting the film sensitivity and is linked to the variable resistor VR ₅ , and the knob 72 is for setting the aperture value and linked to the variable resistor VR ₄ .

FIG. 5 shows another example of an implementation circuit of the display section 40. The operation of the parts denoted by the same symbols as in FIG. 3 is the same as the above. The display differs from that shown in FIG. 3 in that the range display is a direct numerical value displayed by the segment display. The analog multiplexer 100 periodically selects the analog input voltage of the terminals P ₃ and P ₅ by the control circuit 108 and transmits it to the A / D converter 101. The output of the A / D converter 101 is transmitted to decoder circuits 102 and 103 which perform data latch and segment decoding for displaying. The decoder circuits 102 and 103 latch the input data by the control circuit 108 in synchronization with the operation of 100. That is, the decoder circuit 102 repeats the data storage and data refresh of only the digitized data of the input on the terminal P ₃ side at a predetermined cycle, and the decoder circuit 10
In No. 3, only the digitized data input to the terminal P ₅ side repeats data refresh and data storage in a predetermined cycle. The display drive circuits 104 and 105 are decoder circuits 102 and 10,
Digital display 106, 10 according to the decoding content of 3
Drive 7 Reference numerals 106 and 107 are LED segment displays or segment displays such as LCD and EC. In the case of a display device such as an LCD or EC, it is naturally illuminated by a known method in order to enable display confirmation in a dark place. The display is performed as follows.

When the terminal P ₁₂ is H, that is, in the TTL dimming mode, the display drive circuits 104 and 105 are controlled by the control circuit 108 so that display is performed by both the segment displays 106 and 107.

As described above, when the NOR gate G ₁₁ output is in the condition of L, NG ₁ or the character pattern corresponding to it is displayed by the segment displays 106 and 107. When the output of the NAND gate G ₁₀ becomes H, the farthest shooting distance or the proper shooting distance based on the input of the terminal P ₃ is displayed on the segment display 106, and the segment display 107 is displayed.
The latest shooting distance based on the input of the terminal P ₅ is displayed by. The other operations are the same as in FIG. FIG. 6 is an external appearance example of the display unit of FIG.

FIG. 7 shows an embodiment in which the distance display can be displayed not only on the flash device but also on the camera side, and only the part relating to display control on the camera side is shown. Therefore, the flash unit FL side is a portion newly added to the circuit shown in FIG.
On the side of the camera CA, the part newly added to the circuit shown in FIG. 1 is mainly shown. Circuit elements that operate the same as in FIGS. 1 to 3 are denoted by the same symbols.

The pulse generator 153 has a constant period (several 10 m).
A pulse (t ₁ ) of s to several hundreds of ms) is output.
When the pulse (t ₁ ) is transmitted, the transistor Q ₅₀ is momentarily turned on and discharges the capacitor C ₂₀ . Transistor Q
By the periodic discharging operation _50, PTAT of the constant current source I ₂₀
A sawtooth wave is generated by the capacitor C ₂₀ and transmitted to the positive input terminals of the comparators A ₅₀ and A ₅₁ . As described above, the current of the constant current source I ₂₀ is proportional to the absolute temperature, and since the voltage of the terminals P ₃ and P ₅ is proportional to the absolute temperature, it is converted into a time pulse independent of the temperature. This is because. The differentiation and waveform shaping circuits 150 and 151 are comparators A ₅₀ ,
When the output of A ₅₁ changes from L to H, a pulse (t ₂ ,
t ₃ ) is output. The periods of pulses (t ₂ ) and (t ₃ ) are equal to pulse (t ₁ ), but the phases are different for pulse (t ₁ ). The time interval between the pulses (t ₁ ) and (t ₂ ) corresponds to the closest imaging distance transmitted to the terminal P ₅ , and the time interval between the pulses (t ₁ ) and (t ₃ ) is transmitted to the terminal P _3. It corresponds to the farthest shooting distance or the proper shooting distance. When the electronic flash device selects the full-emission mode, the terminal P ₁₂ becomes L, so that the AND gate G ₃₀ is closed and the AND gate G ₃₁ is opened. Therefore, a pulse is output from the one-shot multivibrator 152 after a certain time delay in synchronization with the pulse (t ₁ ), which is replaced with the pulse (t ₂ ). Generation time interval between the output pulses of the pulse (t ₁₎ and the one-shot multivibrator 152 is set to be shorter than the time interval of the pulse (t ₁₎ and (t _2). As will be described later, when the one-shot multi-vibrator 152 is outputting a pulse, the distance display on the near side on the camera side is switched to a character or a pictorial symbol such as "MANUAL".
When the terminal P ₄ is L, the terminal P ₁₁ is H and the terminal P ₁₃ is L, the transistor Q ₅₁ is pulsed (t ₁ , t ₁₎ via the gates G ₃₃ and G ₃₄ .
t _2, t ₃₎ by ON, is turned OFF, the ON-OFF
The signal is transmitted to the camera side via the connection terminal T ₃ . P ₄
H, or P gate G ₃₃ is closed ₁₁ when the PL at L, opens the gate G _35, the one-shot multi-155, t ₁
A pulse delayed by a certain time is generated. At that time, t ₁ and the output pulse of 155 are output from the gate G ₃₄ , and the transistor Q ₅₁ is controlled and transmitted by the camera.

When P ₁₃ H, the gates G ₃₃ and G ₃₅ are closed,
Since the gate G ₃₆ is opened, the one-shot multivibrator 154 generates a pulse delayed by a certain time from t ₁ . At this time, t ₁ and the output pulse of the one-shot multi 154 are output from the gate G ₃₄ to control the transistor Q ₅₁ and transmit it to the camera. One shot multi 15
The delay times of ₂ , 154 and 155 are shorter than the shortest time of t ₂ and different from each other.

[0076] The control circuit 1 via a resistor R ₁₀₀ Camera '
The signal is similar to the foregoing transmitted to the camera when the resistor R ₅₀ of the above small current but is intended for switching the flash photographing mode, in order to prevent a malfunction due to pulsed manner ON of the transistor Q _51, A low-pass filter is formed by the capacitor C ₂₁ and the resistor R ₁₀₀ (t ₁ , t
_There is no malfunction due to the pulse of ( ₂ , t ₃ ). Transistor Q
_{When 40} is ON, transistor Q ₅₁ is turned ON like a pulse
The LED ₁ is momentarily extinguished by the operation, but since it is a pulse that is too fast to be visually recognized as extinguishing, no flicker occurs. Only the pulse generated by turning on the transistor Q ₅₁ is detected by the comparator A ₅₂ and the reference voltage E ₁₀₀ .
It does not respond to the blinking operation of the transistor Q ₄₀ described above.

When the H-level pulse generated in the comparator A ₅₂ is input to the one-shot multivibrator 156, its output outputs a H-level sustain signal for a predetermined period (τ), and a new pulse is generated during the H-level sustain signal period. When input, a new pulse is used as a starting point and the H-level predetermined duration is further continued. This duration is the maximum time (ω ₁ ) from the generation of pulse (t ₁ ) to the generation of pulse (t ₃ ).
The value obtained by adding the duration (τ) to is shorter than the cycle of (t ₁ ). Therefore one shot multi 156
The time width of the H level is ω ₁ + τ, which occurs every cycle of (t ₁ ). One shot multi 15
Reference numeral 7 is a differentiating circuit which outputs only when the output of the one-shot multi 156 changes from L to H, and its output is transmitted to the set input S of the SR flip-flop 158.
Therefore, the pulse (t ₁ ) sets the flip-flop 158, and its output becomes H. The pulse t ₂ transmitted next to t ₁ is transmitted to the reset input R of the flip-flop 158 via the gate G ₄₀ and is transmitted to the SR flip-flop 15
8 is reset and its output goes low. The resistor R ₁₀₁ and the capacitor C ₂₂ form a delay circuit, which prevents the reset pulse from being transmitted to the flip-flop 158 at (t ₁ ). Therefore, the output of the flip-flop 158 becomes H during the time interval (ω ₂ ) from the generation of the pulse (t ₁ ) to the generation of the pulse (t ₂ ). 1
59 is a one-shot multi-156, flip-flop 1
A reference pulse generating circuit for counting the output time of the 58, the one-shot multi 156, the flip-flop 15
During the period of H of 8, the gates G ₃₈ and G ₃₉ are opened and the counters 160 and 161 count time as the number of pulses. When the output of the one-shot multi 156 changes to L, the change causes a data latch pulse to be generated in the data latch circuits 162 and 163 after a predetermined time delay of the one-shot multi 164 to store the count values of the counters 160 and 161. The previous stored value is refreshed. When the one-shot multi 164 generates a data latch pulse, a counter reset pulse delayed by the one-shot multi-vibrator 165 is generated for a predetermined time, the count values of the counters 160 and 161 are reset, and a standby state for performing the next count is obtained. Becomes 16
Reference numeral 6 is a display circuit having a display input switching function.

When 1 is the normal photographing, the display data becomes the input (AV, TV) side from 1 by the signal of the Sig-1 line, and the exposure setting value of the AV and TV values or the expected exposure setting value is respectively displayed on the display. Display is performed by driving 167 and 168. In the flash photographing mode, the display data 1 is switched to the output of the latch circuits 162 and 163 by the signal of the Sig-1 line, and the distances are displayed by the display devices 167 and 168 according to the stored values of the latch circuits 162 and 163. ..

The display is performed as follows. Terminals P ₄ , P
_{When 13} is L and terminals P ₁₁ and P ₁₂ are H, the above (t ₁ ),
Pulses of (t ₂ ) and (t ₃ ) are generated, and due to the above-mentioned operation, ω ₁ + τ, that is, the farthest shooting distance or the proper shooting distance is stored in the latch circuit 162, and the latch circuit 1
In 63, ω ₂ , that is, the latest shooting distance is stored. The indicators 167, 1 according to the stored values of the latch circuits 162, 163.
The distance is displayed by 68. Ω of the latch circuit 162
The stored value of ₁ + τ is τ when transmitted to the display circuit 166.
The term is always excluded. When the terminal P ₁₂ is L, that is, when the terminals P ₄ and P ₁₃ are L and the terminal P ₁₁ is H in the non-dimming mode, the output of the one-shot multi 152 is substituted for t ₂ by the comparator A ₅₁ . In this case, the latch circuit 1
A predetermined time of the one-shot multi 152 is stored by 63, and the display circuit 166 can identify it.
Therefore, the display device 167 displays the proper distance according to the stored value of the latch circuit 162, and the display device 168 displays a pictographic character such as "M" or "MANUAL" that can identify the non-dimming mode.

When the terminal P ₄ is H or P ₁₁ is L, that is, when there is no proper exposure range by flash photography, or when the main capacitor C ₃ is not charged to the light-emission enable voltage, t ₁ and one-shot multi There are only 155 output pulses. It is stored in the latch circuit 163, and the display circuit 1
When 66 identifies the state, the display by the indicators 167 and 168 is in a disappeared state. When the terminal P ₁₃ is H, t ₁ and the output pulse of the one-shot multi-154 are generated. It is stored by the latch circuit 163, identified by the display circuit 166, the display 167 disappears, and the display 168 displays “BOU.
"NCE" is displayed and the flash device takes a bounce shot,
Alternatively, the extension code indicates that the flash device is placed at a position different from the camera position, or that flash photography is performed by the additional light emission. The operation of turning on, turning off, and blinking the LED ₁ is performed in the same manner as in FIG.

FIG. 8 shows an embodiment in which a circuit for adjusting light by the flash device alone is added to the embodiment of FIG. Circuit elements that are the same as in FIG. 2 are labeled with the same symbols. Switch SW ₅₀ , S
W ₅₁ and SW ₅₂ are set to interlock with each other, and terminal a
TTL dimming on the side, and independent dimming on the terminal b side.
Reference numeral 180 denotes a single light control circuit, which is a light receiving element PD ₂₀ on the side of the flash device.
The one-shot multi-circuit 3 based on the photometric current by the and the values of AV and SV set in the variable resistors VR ₄ and VR _5.
Is triggered and the output terminal b performs the operation of integrating the light quantity during the H period, and when the flash light emission reaches a predetermined light quantity, the switch SW
_Produces an output that pulls the 50b terminal to L, and thus the switch S
When W _50-52 selects terminal b, Q ₂₂ is turned on to perform the light control operation as described above. Switch S
When W ₅₁ selects terminal b, the output of gate G ₃ is held at L. As described above, the output of the gate G ₃ is H output when the conditions on the camera side and the conditions on the flash unit side do not match when the TTL dimming is performed, so that the TTL dimming is not performed. . However, in the case of independent dimming, the condition of the camera and the condition of the flash device as described above are not required to be met. Therefore, the output of the gate G ₃ is held at L because no particular warning is required. Switch SW ₅₃
Displays the distance by AV and SV (VR ₄ , VR ₅ ) that can be set on the flash unit side when the AV-SV signal for displaying the distance is not transmitted from the camera side even with TTL dimming. Therefore, the side is switched to the side b, but when the camera is used as in FIG. 1, the side a is selected. Switch SW
₂₀ dimmer, a switch for selecting the non-dimming a similar 2, when the switch SW ₂₀ is ON is selected dimming mode, TTL or selection alone dimming mode by the switch SW ₅₀ to SW ₅₂ To be done. When the switch SW ₂₀ is OFF, the non-dimming mode is selected regardless of the selection mode of the switches SW _{50 to} SW ₅₂ . The distance display in the TTL light control mode is the same as described above. In the single dimming mode and the single dimming / divided light emission mode, A set to the variable resistors VR ₄ and VR ₅
TTL dimming mode and TTL dimming according to V and SV values
The same distance display is performed in each of the divided light emission modes.
In the all light emission mode, the display of the appropriate distance is performed as described above.

[0082]

As described above, the present invention is configured to issue a warning not only when the proper shooting distance is displayed but also when the proper exposure is not obtained by comparing with the distance signal from the shooting lens. There is no danger of shooting with the preset settings.
In addition, it is also displayed whether the distance is near or far, so it is easy to change to the correct setting.

[Brief description of drawings]

FIG. 1 is a camera side circuit diagram of an embodiment of a flash photography display device of the present invention.

FIG. 2 is a circuit diagram of an electronic flash device side of an embodiment of a flash photographing display device of the present invention.

FIG. 3 is a circuit diagram of an embodiment of a display unit of the device of the present invention.

FIG. 4 is an external view of an embodiment of the display unit in FIG.

FIG. 5 is a circuit diagram of another embodiment of the display unit of the device of the present invention.

6 is an external view of an embodiment of the display unit in FIG.

FIG. 7 is a circuit diagram of an embodiment of distance display on the camera side.

FIG. 8 is a circuit diagram of an embodiment in which a circuit for dimming the flash device alone is added to the embodiment of FIG.

[Explanation of symbols]

50, PD ₁₀ , A _{31 to} A ₃₃ photometric device 1 means for generating second flash information T ₂ output terminal SW ₃₀ means for detecting Q _{30 to} Q ₃₃ , A ₃₀ transmitting means

Continuation of front page (56) Reference JP-A-56-4133 (JP, A) JP-A-54-43021 (JP, A) JP-A-54-108627 (JP, A) JP-A-56-97331 (JP , A) Actual development 57-7020 (JP, U) Actual development 54-163649 (JP, U)

Claims (7)

[Claims] 1. An electronic flash device for emitting flash light for photographing or a camera incorporating the same, wherein in the photographing information, any two information of aperture value information, guide number information and distance information, and film sensitivity. Based on the information and three pieces of information, for flash photography, the above 2
Creating means for creating a reference signal indicating an appropriate value of the remaining information not selected as one piece of information, and a predetermined width signal having an allowable range for the appropriate value by giving a predetermined width to the reference signal A predetermined width setting means for outputting, an acquisition means for acquiring the remaining information that can be changed according to conditions, and outputting an acquisition signal based on the acquired information, the acquisition signal and the predetermined width signal. In comparison, the display control means controls the display means such that the display form is different when the acquisition signal is within the predetermined width of the predetermined width signal and when it is outside the predetermined width. Electronic flash device or a camera incorporating it. 2. The electronic flash device according to claim 1, wherein the acquisition unit acquires the remaining information that changes when a photographer operates the electronic flash device or a camera incorporating the electronic flash device. Or a camera with a built-in one. 3. The display control means, when the remaining information is outside the predetermined width, whether the remaining information exceeds a maximum value of the predetermined width or is below a minimum value. 2. The electronic flash device according to claim 1, or a camera incorporating the electronic flash device, wherein the display means displays which direction the shift is made. 4. The display control means prohibits the display in the direction of the shift of the display means when the charge storage member for storing the charge for the flash light emission is not in the storage completed state. Item 1. The electronic flash device according to Item 1, or a camera incorporating the same. 5. The display means has a first display member indicating a direction exceeding the maximum value and a second display member indicating a direction below the minimum value, and the remaining 4. The electronic flash device according to claim 3, or a camera incorporating the electronic flash device, wherein the first and second display members are driven when information is within the predetermined width. 6. The electronic flash device according to claim 1, or the camera incorporating the electronic flash device, wherein the display control means does not control the display means when the photographing information is not transmitted from the camera. 7. The electronic device according to claim 1, wherein the display control means displays a warning in the viewfinder of the camera when the signal from the acquisition means is outside the predetermined width. A flash device or a camera that incorporates it.