JPS58224334A - Flash photographic device - Google Patents

Abstract

PURPOSE:To obtain invariably optimum exposure for flash photography by switching a dimming mode wherein the amount of lighting is settled on the basis of a distance and an aperture value to a TTL dimming mode in response to the attachment of accessaries such as a filter and an extension ring. CONSTITUTION:When an accessary such as an ND filter is attached, a switch SW14 is turned on and a mode switching circuit CSW seects a contact (a) regardless of the state of a manual switch SW13. Consequently, the TTL dimming mode is selected and light metering SP1 of film surface reflected light, integration iNT1, and lighting stop signal output CP1 are carried out to stop lighting through a dimming circuit CNT. When no accessary is attached and the manual switch is off, a contact (b) is selected to set the dimming mode. At this time, the amount of lighting is calculated at a part CAL on the basis of distance DVL, aperture AVL information, etc., to perform lighting stop control based upon direct light metering SP2 and integration iNT2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic exposure control device for flash photography.

The following system has been known as an automatic exposure control device for flash photography.

■ The flash device is equipped with a light-receiving element that receives reflected light from the subject, the light reflected from the subject is detected by the light-receiving element provided in the flash device itself, and light reception is stopped when the amount of light received reaches a predetermined value. External flash adjustment system (auto strobe system) (Auto strobe system) The light reflected from the subject by the flash is received by the light receiving element in the camera through the camera lens and diaphragm. ,
When the amount of received light reaches a predetermined value, the flash light emission is stopped, and the flash light emission b1. A TTL light control system (general) that calculates a guide number based on the lens distance ring or distance information from the lens position and the set aperture value,
Distance light control system for controlling flash light emission using the calculated guide number However, all of the above methods (1) to (3) have the following drawbacks, and cannot completely obtain proper exposure.

■ External light control: Because the light-receiving element that receives flash light is installed independently of the camera's photographing optical system, the photographing area of the camera lens and the light-receiving area of the light-receiving element for light control do not match15, making it difficult to accurately It is not possible to detect the amount of flash in the shooting area. However, since the photoelectricity received by the photodetector changes depending on the reflectance of the subject, proper exposure cannot be obtained.

■ T i' L 414 light: As with external light control, proper exposure cannot be obtained because the received light changes depending on the reflectance of the subject.

■Distance controlThe flash output is determined by the aperture value and subject distance, so if a device that changes the amount of light transmitted through the lens, such as an ND filter, is installed, the amount of light that is cut by the ND filter may result in underexposure. V'' to change the distance such as ta ′″, y ′Z −1−
Similarly, proper exposure cannot be obtained when using the lens intermediate adapter. In other words, when the magnification becomes M times when the photographing lens is extended for 1ri in a close-up barrel shape by attaching an intermediate ring, etc., the actual aperture is (M+1) times the aperture value marked on the lens. Get dark. As a result, there is a difference between the actual aperture value and the set aperture value (lens scale value), and distance flash control, which controls the flash flash based on the set aperture value (direct and distance values), may result in incorrect exposure. It's hard to get.

The present invention aims to eliminate the disadvantages of the distance dimming method and the '11' T L dimming method described above, and effectively utilize the advantages of the distance dimming method and the TTL dimming method, and has the following characteristics: When accessories such as filters and intermediate adapters are attached to lenses that have variable transmission light intensity characteristics, the flash mode is automatically switched from distance light control mode to TTL light control mode. To provide a flash photography device which can automatically select a light control mode convenient for the photographing condition and perform flash photography.

Next, a flash photography device according to the present invention will be explained. FIG. 1 is a block diagram showing an embodiment to which a flash photography device according to the present invention is applied.

In the figure, CA indicates a camera, l indicates a photographic lens such as an interchangeable lens, and DV is linked to a focusing ring provided on the photographic lens barrel to generate an output according to the logarithm of the set distance. It is a set distance signal forming means such as a variable resistor.

The means is not limited to a variable resistor, but may be constructed from a digital switch, a digital code board, or the like.

The 2id aperture, AvL, is a set aperture signal forming means such as a variable resistor that generates an output according to the logarithm of the set aperture value in conjunction with the aperture ring. Of course, the means may also be constructed of a digital switch, a digital code board, etc., like the DVL. Reference numeral 3 denotes a movable mirror which is moved upward from the position shown in the figure by the release operation and blocks light from the optical path to the pentagonal prism 4 during exposure;
This is a light-receiving element that receives the light beam reflected by the film surface out of the light beam irradiated on the film surface.

sw, , sw, is a switch provided on the photographic lens, SW, , is a manual mode selection switch that is turned on and off manually, and 5w14 is a lens equipped with a variable amount of transmitted light member such as an ND filter. A mode selection switch is a mode switching signal forming means that is turned on to form a mode switching signal, and these switches are connected in parallel.

C8W is a mode switching circuit that connects to contact a when the switch 8W or SW is turned on, and connects when both switches SW, 3 and SW, 4 are turned off. The switching circuit includes a switch sw, 3. Connect to sw, , [7,
A transistor switching circuit, an analog switch, a gate selector formed by a Uj logic element, etc., which performs a switching operation according to the state of the switch, are used.

INTt is an integrating circuit that integrates the output of the light receiving element SP; L is a compression means that logarithmically compresses the output of the integrating circuit;
L outputs a compressed value of the optical ambiguity value received by the light receiving element SP. The film sensitivity information forming means generates an output corresponding to the logarithmic value of the set film sensitivity in conjunction with the SVL film sensitivity setting means, and the means is constituted by a variable resistor, a digital switch, or the like.

A light emission stop signal forming circuit for the CPI-TTL dimming mode, which outputs a light emission stop signal when the output of the compression means reaches a predetermined setting value set by the film sensitivity information forming means 8VL. .

The light emission stop signal forming circuit is composed of a comparator and the like.

C A L ij 1) V L , A V L
, 8 V L Color (7) An arithmetic circuit that calculates the output, and this circuit executes appropriate flash photography for each means DVL, AVL, 5VL (1') output'<Ex.3'l, each set value. It generates an output corresponding to the logarithm of the amount of light emitted needed to do so.

CP is a light emission stop signal forming circuit for the distance 1111I dimming mode, which detects the output of the compression means described later and the output of the arithmetic circuit, and stops light emission when both outputs meet a predetermined relationship. Output a signal. This circuit also has the same configuration as the circuit CP described above.

8T is a flash device such as a strobe attached to the camera CA, XE is a flash tube, SPz&: is a light receiving element that receives the flash from the flash tube XE, and CNT stops the flash from the flash tube in response to the light emission stop signal. This is a dimming circuit that Either method of dimming by serial control or dimming by parallel control may be used with the light control circuit.

A, F3. Is C a flash? ? , shows the terminal for connecting the position T and the camera CA.

1, NT2 is an integrating circuit connected to the light receiving element SP via the terminal A, which integrates the output of the light receiving element SP, and outputs a value corresponding to the amount of flash light emission as the output of A. The integrating circuit INT2 is the compression means described above.

As described above, L generates an output corresponding to the logarithm of the integral output, that is, an output corresponding to the logarithm of the amount of flash light emission.

The light receiving elements SP, BP, and the light emission stop signal forming circuit C
P+ * CPt, performance J1 circuit CA L1 dan division jM
INT+.

IN'l''2 and the dimming circuit CNT constitute an adjusting circuit for flash light emission.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

Now, when taking pictures, it is assumed that a member such as an ND filter that has a characteristic of reducing transmitted light deception is attached to the photographing lens l. In this state, switch SW,4 is turned on, and switching circuit C8W is connected to contact a and connection 1. -r is there.

Let's assume that the control mode of the camera has been changed to flash mode, IJJ, and that the aperture and distance adjustment operations are being performed. When the release is performed in this state, the mirrors 3 line up and the front curtain of the shutter moves as is known.
In conjunction with this, the synchro switches SW, ... are turned on, and the flash tube XIJ is triggered by the action of a trigger circuit (not shown) to start emitting flash light.

The subject is illuminated by the flash, and the light reflected from the subject by the flash is preset on lens 1] 7 and aperture 2
The light is irradiated onto the film surface through the filter and the light reflected from the film surface is received by the light receiving element SP.

Light receiving element SP.

The output of is integrated by an integrating circuit lNTl, and the integrated value is logarithmically compressed by a compression means. Therefore, the light emission stop signal forming circuit CIO includes a light receiving element SP.

The logarithmic value of the photoelectricity received by the photoelectric sensor is transmitted, and when the logarithmic value has a predetermined relationship with the output of the film sensitivity information forming means SVL, the light emission stop signal forming circuit CP outputs a light emission stop signal.

As mentioned above, since the switching circuit COW is connected to the contact a, the light emission stop signal is transmitted to the dimming circuit CNT via the switching circuit C8W and terminal B, and the flash light emission by the flash tube XE is stopped, and the TTL%4 light is executed. It goes without saying that the shutter time is controlled by a predetermined synchronization time such as 1/60 seconds.

Next, a case will be described in which flash photography is performed without attaching a filter or the like to the lens l. In this case, switch sw
, s, sw, 4 are both in the off state, and the switching circuit C8
W is connected when it contacts.

Now, as in the case above, it is assumed that the flash mode has been selected and the aperture preset and distance adjustment have been executed.
If you perform the release operation in this state, the mirror 3 will rise, the shutter front curtain will move, and the synchro switch SW will be activated.
is turned on and a flash is emitted from Flash-1iXE.

The flash from the flash tube XE is received by the light receiving element SP, and the amount of flash appears as an integral value of the output of the light receiving element SP at the output of the integrating circuit INT2. The output of the integrating circuit INT2 is logarithmized by the compression means Lt, and transmitted to the light emission stop signal forming circuit CP2.

On the other hand, the arithmetic circuit CAL is a signal forming means I)VL.

The preset aperture value, distance value, and film sensitivity value from AVL and SVL are calculated, and a logarithmic value signal of the amount of flash light necessary to execute appropriate flash photography is output, and this signal forms the above-mentioned flash stop signal. It is transmitted to the circuit CP. Therefore, when the output of the compression means has a predetermined relationship with the output of the arithmetic circuit CAL, the light emission stop signal forming circuit outputs the light emission stop signal and stops the light emission via the switching circuit C8W and the terminal B. The signal is transmitted to the dimming circuit CNT, the flash light emission by the flash tube XE is stopped, and distance dimming is executed. Of course, in this case as well, the shutter time is controlled by the synchronization time.

Furthermore, when an operation member (not shown) provided on the lens l is operated, the switch SW, 3 is turned on, so that even if a filter or the like is not attached to the lens, the switching circuit is connected to the contact a, and the above-mentioned T T L Flash photography is executed in the ilQ mode.

As described above, in the present invention, flash intermittent control is normally executed by distance dimming, and exposure errors due to subject reflectance can be prevented, and when a filter etc. is attached, Nl) Since the I''TL light control mode is selected, even in this case, the amount of flash light can be adjusted correctly without being affected by the filter's effect of reducing the amount of transmitted light.

In the embodiment shown in FIG. 1, for distance dimming, the flash from the flash tube XE is received by the light-receiving element S, and this is integrated and compared with the calculated value, and when the two have a predetermined relationship, the flash is activated. We have shown an example of stopping the flash, but if we set up a regulation circuit that regulates the amount of charge in the main capacitor of the flash device, the calculation circuit C
There are models that calculate the amount of charge in advance based on the output of the AL and regulate the amount of charge based on this to control the amount of flash, and a timer that measures time according to the output of the calculation circuit is installed to calculate the flash emission time. In any case, a type in which the amount of flash is controlled based on a set distance, such as a type in which the amount of flash is controlled based on a set distance, can be applied.

In addition, in the embodiment, as a light emission stop signal forming circuit, T'r L
Although one for dimming and one for distance dimming are provided separately, a single one is provided as a light emission stop signal forming circuit, and the input part of this circuit is set according to the state of switch 8wl31SW. An input switching circuit is provided to control the signal switching operation, and inputs the output of the compression means and film sensitivity information forming means S V L in the case of 'r 'r L I1g, and also inputs the output of the film sensitivity information forming means S V L. In this case, the outputs of the arithmetic q1 circuit CA L and the compression means L2 may be input. of course,
In this case, the switching circuit C is connected to the output part of the light emission stop signal forming circuit.
There is no need to provide 8W.

Further, in the embodiment, the light emission stop signal forming circuit is provided on the camera side, but the circuit may be provided on the flash device side.
A flash device may be incorporated into the camera and the camera and flash device may be integrally configured.

Furthermore, in the embodiment, the integration circuits and compression means for the TLA light and the distance dimming are provided independently, but it is possible to provide a single integration circuit and compression means,
Of course, it is also possible to use -C, which is constructed so that the light-receiving element is switched and inputted to the integrating circuit during L light control and distance light control.

Furthermore, although this embodiment describes the case where distance adjustment is performed manually, when distance detection is performed with an autofocus device, the distance information detected by the autofocus device is directly input to the calculation circuit CAL. Of course, it would be better if you input it in the following manner.

Next, a specific embodiment of the flash photography device shown in FIG. 1 will be described with reference to FIGS. 2, 3, 4, and 5.

FIG. 2 shows an example of a specific configuration of the camera C shown in FIG. Depending on the resistance value, the closer the set distance value is, the higher the output level will be. The amplifier OP and the variable resistor DB constitute the distance signal forming means. AR is a variable resistor that constitutes the aperture signal forming means AVL=i, and the output of this resistor outputs a lower potential as the aperture is narrowed down.

8IJ, variable resistor linked to film sensitivity setting means, U
P, has a resistance It between its - input terminal and output terminal.

is connected to an operational amplifier, which acts as an inverting amplifier, and its output becomes higher in potential depending on the set film sensitivity value, and the higher the set film sensitivity is. The amplifier OP...
and a resistor 81L constitute the film sensitivity information forming means.

OP is an operational amplifier connected to the amplifier OP via a resistor R, to the amplifier OP4 via a resistor island, and directly connected to the variable resistor AR. A resistive island is connected in the return path of the OP77102 layer and acts as an inverting amplifier.

Therefore, the output of cough amplifier UP, the lower the film sensitivity,
Alternatively, the longer the subject distance is, or the more the aperture is narrowed down, the higher the potential is output. The amplifier OPs constitutes the arithmetic circuit CAL.

OP2 is an operational amplifier that constitutes an inverting amplifier together with resistors L and R, and the R amplifier is the amplifier OP.

The output of is input. Therefore, the higher the film sensitivity, the lower the output voltage of the amplifier UP.

SPI is a phototransistor constituting the light receiving element, C5 is a capacitor connected in series to the phototransistor SP, SW is a switch that is linked to a synchro switch S, and the switch SW is a switch S.
When W, , is on, it is off.

The above-mentioned integrating circuit INTz is composed of the capacitor 〇 and the switch SW.

SP is a phototransistor constituting the light receiving element; Cv is a capacitor SW connected in series with the phototransistor S; is a switch that is linked to the synchro switch SW, , and 0 is the switch SW.
When W, , is on, it is off.

The integration circuit INT2 is composed of the capacitor 〇 and the switch SW.

CP, CP, are comparators that constitute the light emission stop signal forming circuit.

■, is an inverter, A, and A are an AND gate, O
R, is an OR gate, and these logic elements constitute the switching circuit C8W.

OP and s are buffer amplifiers to which one input terminal of the capacitors 0 and 2 are connected, and the output V of the amplifier i is connected to the base of the transistor lit, and the transistor 1i1 is connected to the collector of the transistor lit. 'r
, is a transistor whose emitter is jfH connected to the emitter of the transistor l1lr2, and whose base is connected to the collector of the transistor/sister Tr.

The collector of the transistor T, , is a diion 5D D.
i, is connected to. OP is an operational amplifier whose one input is connected to the diode 1) 11, and the other input is connected to a voltage dividing point of a series circuit of a feedback resistor and a resistor ItLl. These amplifiers OP, , OP, ,
Transifter'l rI + ']"2 + 'I
'ms resistance 1 (I, I, and diode D
The compression means (1) is formed in iI, and the capacitor C
It produces an output corresponding to the logarithm of the output of 1. OP...
OP,, 'rr,, Tr,, 'I”r,, I)
i2.1 (upper I.

d: an operation up, a transistor, a diode and a resistor forming the compression means 1i2;
They are respectively connected in the same way as the compression means (I).

FIG. 3 is a configuration diagram showing an embodiment of an intermediate adapter such as a photographic lens and a teleconverter applied to the flash photography device according to the present invention.

In the figure, 1 indicates the photographing lens barrel shown in the first figure, and l
l is a lens. The lens barrel is provided with the switch Sν.
Fixed contact piece Sw, 4b forming +4, movable contact piece 5W14a pressed by the bottle part 110, and the switch SW
, , a fixed contact piece 5w1sb and a movable contact piece 13a interlocked with the mode switching manual operation member 2o are provided. to the switch S.

5W14 are connected in parallel as shown in the second diagram.

6a is a ground contact provided on the back surface of the bowl, 7a is a mode switching signal contact, and between the contact 7a and the ground contact 63, the switch sw, 3. sw, 4 is connected.

15b is a resistor board on which the resistor shown in the second figure is disposed;
Reference numeral 5a denotes a contact piece that slides on the substrate L S b in conjunction with a distance ring (not shown) provided on the lens barrel, and these contact pieces and the substrate form the set distance signal forming means D V L
is configured. The contact piece is connected to the ground contact 6a, and the substrate 151) is connected to the distance signal contact 8a.

12a and 16a are automatic aperture lever pins for controlling the aperture, and 16a is an aperture signal lever pin for transmitting the set number of aperture stages of the photographing lens to the camera. A mounting part for mounting the filter 6 is provided on the front surface of the lens barrel, and by mounting the filter 6 on the lens barrel, the pin member 10
is pressed by the filter, turning on switch SW, 4.

Reference numeral 9 indicates a camera body, and 8 is a mounting portion for mounting a photographic lens barrel provided on the camera body. Contact points 6a, 7a, 8 provided on the lens barrel are provided on the camera body.
Contacts 6d, qd, and 8d connected to a are provided.

Reference numeral 7 denotes an intermediate adapter such as a teleconverter, which is used by being attached between the photographing lens barrel l and the camera body 9. The front surface of the adapter has contacts 6b and 8b opposite to the contacts 6a and ga provided on the lens barrel.
is provided. Further, on the back side of the adapter, contacts 5c, 7c, and 8C are provided to connect to the contacts 5d, 7d, and 8d provided on the camera body, respectively. The contact 8b and the contact 8C are connected by a signal line,
Contact point 6b, contact point 5c, and contact point 7C are connected by No. 100 line.

16b and 12b indicate an aperture signal lever pin and an automatic signal lever pin, respectively.

FIG. 4I''i is an embodiment showing a specific configuration of the flash device S'v shown in the first figure.
, a rectifier diode DlO1, and a coil Li, which is a known main capacitor supplied with power from a power source P8. A diode D102 connected in parallel to the coil L is a noise killer diode. Resistance 1t102, neon tube N
E, the series circuit consisting of resistor 103 is the main capacitor -C
This is a detection circuit for detecting a charging voltage of 1O1, and one end of the circuit is connected to the cathode of a thyristor 80101 via a capacitor C102, and is also connected to the camera-strobe terminal C. The thyristor SCf is also a thyristor forming a 1OIFi trigger circuit, and its anode is connected to the resistor R105 and the coil L.
is connected to the main capacitor -C1,01 via the trigger, and its cathode is connected to the trigger and the primary winding of the transformer TT #! is connected to the tricar condenser ClO3.

Furthermore, the gate of thyristor 5citi 01 is resistor 1t1
Connected to 04. XE is a known discharge tube, and the discharge tube
One 'electrode of E is a thyristor 5CI (1
02 to the main capacitor -Cl0I, and its trigger opening is connected to the secondary winding of the tricar transformer. Between the main electrodes of the main thyristor 5C)L1o2, there is a commutation conte 7"j--C104, a sub"j(
A known circuit consisting of RISK 5 CIL 103 is connected in parallel and still has resistors 11, 106 and R108 at its gate.
, a known thyristor trigger circuit consisting of a capacitor 0105 is connected. R107 has 80 thyristors 1
This is a resistor connected in parallel to 02. Discharge tube
The series circuit t consisting of the diode D104 and the run risk T) 101 is also a v4 operation prevention circuit that prevents the auxiliary thyristor SC 103 from becoming conductive before the discharge tube XE starts emitting light. The collector of the npn run risk TR101 of the prevention circuit is connected to the strobe-camera terminal B via a resistor 1 (113e).

The phototransistor SP is arranged near the discharge tube XE as shown in FIG. The operation of the embodiment of the present invention shown in FIGS. 2 to 5 will be described.

First, a case will be described in which the filter 6 is attached to a photographic lens and flash photography is performed.

゛ When the filter 6 shown in Fig. 3 is attached to the lens barrel 1, the bottle member 10 is pressed and the contact pieces SW, , a and 5WI
4b are in contact with each other. Since the lens end l is attached to the camera body 9, the contacts 6a and 6d and the contacts 7a and 7d are connected, and the ON information of the switches 8W and 4 is obtained by contact between the contact pieces SW and 4a and 8W14b. is transmitted into the camera body.

By turning on the switch SW, a low level signal (hereinafter referred to as "'0" signal) is applied to one input terminal of the AND gate A2 in FIG.
A high level signal (hereinafter referred to as F"1" signal) is applied to one input end of F"1" through an inverter (2).

l AND gate A is a gate for T'r L dimming, and AND gate A2 is a gate for distance axis light, so
']'This means that the TL dimming mode has been selected.

After performing the aperture adjustment and distance adjustment operations, when the release button is pressed, the mirror is raised and the shutter front curtain is moved, and in conjunction with this, the synchro switch SW is turned on.

The on signal of the switch SW, , is applied via the terminal C to the resistor R103, rtto4, capacitors ClO2, ClO3, and thyristor sCR of the flash device (FIG. 4).

101, the signal is transmitted to a known trigger circuit composed of a transformer TT, and the thyristor 8C) 101 is turned on, and the charge in the capacitor C103 is transferred to the transformer 711.
Flow to the primary winding of Tr transformer 'I' T is discharge tube Xh
Trigger i, turn on Cyrisk-8CR102, and start flashing light.

The reflected light from the subject due to the light emitted by the radiator tube is irradiated onto the film through the filter photographing lens diaphragm, and the reflected light from the film is received by the light receiving element Sη. S.P.I.
collects the linear current according to the intensity of the incident light.
Since the current flows between the emitters and the switches SW, , are turned off in conjunction with the switches SW, , the capacitor C7 is charged with the current. The charging Km pressure of the capacitor C1 is logarithmically compressed in the compression stage L1, and is compressed by the comparator CP.

is applied to the (+) input terminal of. the comparator CP,
The (-) input terminal of the amplifier O acts as an inverting amplifier.
A voltage corresponding to the set film sensitivity value is applied to the resistor SR via P, and when the charging voltage of the capacitor C1 reaches a value corresponding to the set film sensitivity, the comparator CP stops flashing. Outputs l'' signal as a signal 0 As mentioned above, the amplifier OP outputs a lower pressure as the film sensitivity value is higher, so the time from the time of flash emission until the comparator CPI outputs the flash emission stop signal The higher the film sensitivity, the shorter the time.The comparator CP
, the l” signal from AND gate A and OR gate O
It is transmitted to terminal B via the wire. By transmitting the "'1" signal to the terminal B, a gate current is supplied to the gate of the thyristor 5CRIo3, and the thyristor 5C)tl03
is turned on, charging of commutation capacitor CIO2
The load is discharged through the thyristor 5C) t103, reverse biasing the thyristor 8CH, 102, turning off the thyristor scu, to2, and discharging the thyristor 5C through the tube X, 1(
The flash emission caused by this will be stopped.

As shown below, if a part such as a filter that changes the transmission angle of light incident on the lens is attached to the lens barrel, it will be automatically 'r 'r t, using the dimming method. As long as flash photography is performed, even if the amount of light transmitted through the lens changes, an appropriate flash exposure adjustment operation will be performed.

Next, a case in which flash photography is performed without a filter attached will be explained.

In this case, the contact piece 5W14a of the photographing lens barrel shown in FIG.
and 5WI4b and SW, a and 8WIs b l are in a non-contact state. Therefore, the contacts 6a and 7a are in an open state, and the open signal is introduced into the camera body via the contacts 5d and 7d. The open signals from the contacts 6a and 7a are applied to one input end of the antagonist at 1-7 as the ``1'' signal, and are output to 0'' through the inverter.
It is applied as a signal to one input terminal of AND gate A. Therefore, in this platform, the -r node gate AI is prohibited, and the AND gate A2 for the distance dimming mode is selected instead.

When the distance ring on the lens barrel is operated to adjust the distance, the contact piece 15a slides on the resistance board 15b, and a resistance value corresponding to the set distance value is set. The substrate 15b and contact piece 1
5a is a contact point 5a.

8d, the resistance value between the contacts □a and 8a is introduced into the camera body via the contacts 5d and 8d.

As described above, the board 15b, the contact piece 15a I! Since it constitutes the resistor 1) It in FIG. 2, the amplifier OP4 outputs a voltage corresponding to the set distance information.

Further, when the aperture ring on the lens barrel is operated to set the aperture value, the set aperture value is introduced into the camera body via the aperture signal lever bin 16a' and is set as the resistance value of the resistor Alt.

After adjusting the distance and adjusting the aperture as described above, when the shutter button is pressed and the release operation is performed, the synchro switches S to ■ and 2 are turned on in the same way as in the TTL light control mode described above. Therefore, the switch SW,
The discharge tube XB starts flash discharge at the 20 ON signal. The flash of the discharge tube is received by a light receiving element SP close to the discharge tube XE as shown in Figure 5, and the light receiving element 5P211 outputs a current according to the intensity of the flash from terminal A to the camera side. The switch SW, , is in conjunction with the synchro switch SW, , and is off at the start of flash light emission, so that the capacitor C2 is charged with the output current of the light receiving element SP.

As mentioned above, since the light receiving element SP2 directly receives the flash light from the discharge tube XH, the charge level of the capacitor C7 1JLit represents the amount of flash light emitted from the discharge tube. The decompressed output of the capacitor C3 is logarithmically compressed by the compression means L2 and applied to the (+) input terminal of the comparator CP.

The amplifier OP3 includes amplifiers OP, OP4, . . . corresponding to film sensitivity values and subject distance values. The output of the resistor AI (corresponding to the aperture value) and the output voltage of the resistor AI (corresponding to the aperture value) are inputted, and the amplifier OP3 calculates the amount of flash necessary to obtain the appropriate exposure by calculating each information, and calculates the amount of flash necessary to obtain the appropriate amount of flash. The voltage at the output t of the UP is the voltage at the comparator CP.

(-) applied to the human power, said voltage and said compression means 0 stages,
A comparison is made with the output of the amplifier OP, which is the logarithmic value of the charging voltage of the capacitor C1, i.e., the amount of flash emitted from the tube has reached the output of the amplifier OP, i.e., the amount of flash necessary to obtain proper exposure. Comparator CP.

A ``1'' signal as a light emission stop signal is output from .

-r node gate At responds to the ``1'' signal.
"Outputs the signal (or game) via OR, and terminal B,
Thyristor 8 (ILI) of the T+ double signal flash device
The signal is transmitted to the gate of O3, and the flash light emission is stopped in the same manner as in the case of the TTLffl light described above.

As described above, in flash photography without using a filter or the like, flash photography is performed in the distance light control mode, and the amount of flash light is adjusted appropriately without being affected by the reflectance of the subject. Furthermore, even if a filter is not installed,
When the operating member 20 provided on the lens barrel is pressed down,
Since the contact pieces sW, 3a and 8W+sb come into contact, the switch SW, 8 is turned on, and an on signal is applied between the contacts 6a and 73. Therefore, in this case, flash photography is performed in the TTL light control mode, similar to when the above-mentioned filter is attached.

Next, a case where an intermediate adapter 7 such as a teleconverter is installed between the lens barrel l and the camera body 9 will be described.

Since the contacts 6C and 70 of the intermediate adapter 7 and e are short-circuited, when the intermediate adapter is attached (unfortunately, the ON signal 4g is applied between the contacts 6d and 7d of the camera body 9. Therefore, in this case As with the case when the filter is attached as described above, the flash amount is adjusted in TT[, g light mode, so the aperture value set on the lens barrel using an intermediate adapter such as a teleconverter is Proper exposure can be obtained even when flash photography is performed with different aperture values.

FIG. 6 is a circuit diagram showing another embodiment of the camera shown in FIG. 2, and the same components as in the embodiment of FIG. 2 are given the same symbols. In the embodiment shown in FIG. 6, a resistor J(, ) is connected in series with a variable resistor JJ()L for distance information setting, and the potential at the connection point of the resistor is calculated using
Once the threshold level is exceeded, set the switch SW again.

SW, , are connected in parallel to the resistor to reduce the number of terminals that serve both as a distance information signal transmission terminal and a mode switching signal transmission terminal. The operation of the embodiment shown in FIG. 6 is the same as that of the embodiment shown in FIG. 2, so the explanation thereof will be omitted. In the embodiment, a filter and a teleconverter are shown as accessories for making the transmitted light t variable, but it goes without saying that this is not limited to this.

As described above, in the flash photographing device according to the present invention, the influence of the reflectance of the subject is usually adjusted in the distance light control mode. When a transmitted light amount variable member such as a filter or an intermediate adapter is attached, the light intensity adjustment automatically changes from the distance p'% light mode to the rTL light mode. It is designed to switch the flash mode and adjust the flash amount in TTL dimming mode, so even with this stand, it is possible to properly attenuate the light without being affected by the transmitted light amount variable member. It can be guaranteed, and has great effects in flash photography devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a flash photography device according to the present invention, FIG. 2 is a circuit diagram showing an embodiment of the camera CA shown in FIG. 1, and FIG. 3 is a block diagram showing an embodiment of a flash photography device according to the present invention. FIG. 4 is a configuration diagram showing an embodiment of the photographing lens chain, filter, and intermediate adapter applied to the flash device S shown in FIG. 1.
5 is a circuit diagram showing one embodiment of T, FIG. 5 is a configuration diagram showing the arrangement relationship between the light receiving element SP shown in FIG. 4 and the discharge tube XE, and FIG.
The figure is a circuit diagram showing another embodiment of the camera shown in the second figure. sw, ,, sw,...switch, C8W...
・Switching circuit, l...Photographing lens barrel, 7...Intermediate adapter Patent applicant Canon Co., Ltd. agent Gyoshi Marushima

Claims (1)

[Claims] The first mode adjusts the amount of flash light based on subject distance information and aperture value information, and the first mode receives the amount of light reflected from the subject due to flash light, and when the received light amount reaches a predetermined value, the flash light is applied to the subject. Equipped with a flash percentage amount control circuit that has a second mode that stops irradiation and adjusts the flash amount, and a mode switching circuit that switches from the first mode to the second mode in response to attachment of accessories. A flash photography device characterized by: