JPS6057331A - flash device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a flash device, particularly a pre-flash section separate from the main light-emitting section, lights up the pre-flash section of the flash device, measures the light reflected from the subject, and calculates the amount of light received. The present invention relates to a flash device that selects a light control aperture value accordingly, outputs camera side ρ information, automatically determines the camera aperture, and performs automatic light adjustment using the aperture value.

In a flash device having a main light emitting part and a pre-light emitting part as described above, and determining the aperture of the camera 2 by the pre-flash, there is a main capacitor that stores the light emitted energy of the main light emitting part, and a main capacitor that stores the light emitted energy of the pre light emitting part. and a sub-capacitor, and an indicator such as a neon tube for indicating that the flash device is ready to emit light when the charge accumulated in both capacitors reaches an amount capable of emitting flash light. It is used. Therefore, even after the display indicates that the flash device is ready to emit light, the charge accumulated in both capacitors continues to increase, so that the display indicates that the flash device is ready to emit light, and the flash device is ready to emit light. When the light is emitted, and when the pre-flash is emitted after a certain period of time has elapsed after the display indicates that the light can be emitted, the y! ! , the display of distance, that is, the shooting distance at which the flash device can be used, had changed. However, although the photographer uses the display to confirm that the flash device is ready to emit light, the display often does not indicate the amount of increase in the charge on the capacitor, so he may have to check the display accordingly. The photographer does not realize that the amount of charge accumulated in the capacitor increases even after the display is displayed. Therefore, even though the status of the flashable display does not change, the subject at the same position is within the linked distance between the pre-flash immediately after the flash-ready display and the pre-flash after a certain period of time. The display of whether or not it exists has changed. Therefore, there is a drawback that the photographer may think that the operation of the flash device is unstable and that the flash device is unstable or that it is malfunctioning. Further, the aperture value of the camera, which is set depending on the result of the pre-flash, may change for reasons described below. For example, if you attach the flash device mentioned above to your camera and take continuous shots after fully charging both capacitors of the flash device before taking a picture, the capacitors will be fully charged by the time you take the first shot, so the pre-flash will be activated. There are many sights. However, from the first shooting to the second and third shooting, instead of charging the capacitor until it is fully charged,
For quick photography, when the voltage of the capacitor reaches the voltage that enables light emission, that is, immediately after the display indicates that multiple flashes are possible, the picture is taken, so the voltage of the capacitor is lower than that at the time of the first picture. It's low and there are few pre-flash scenes.

Therefore, the light amount of the pre-flash differs between the first and second and subsequent times, and the level of reflected light from the subject differs, so the aperture on the camera side may also differ between the first and second and subsequent times. Therefore, there is a drawback that the depth of field at the time of photographing changes between the first and second photographs, resulting in differences in the resulting photographs.

In view of this point, the present invention aims to eliminate the above-mentioned drawbacks. The present invention will be explained in detail below using the drawings.

Fig. 1 is a circuit connection diagram of an auto strobe in a flash photography device to which the present invention is applied.
A known Dl, DC converter 3 that boosts the low voltage of is connected. Two rectifying diodes 4 and 5 are connected to the converter 6, and the anode of the main thyristor 1B is connected to the cathode side of the diode 4 via an L coil 12 and a main discharge tube 13 for photographing. In addition, the diode 5
On the cathode side of the sub-capacitor 6 for supplying luminous energy to the distance-measuring sub-discharge tube 7, and a series circuit of a Zener diode 143 and a resistor 144 for detecting the voltage of the sub-capacitor 6, a parallel circuit is connected via a transistor 140. connected. A resistor 145 and the emitter collector of a transistor 141 are connected between the emitter and base of the transistor 140, and the base thereof is connected to the emitter of a transistor 142 via a resistor 147, and the base is connected to a resistor 141.
48 to the connection point between the Zener diode 143 and the resistor 144.

A trigger circuit 8 is connected to the trigger electrode of the sub-discharge tube 7, and a monostable multi-pipe lake 130 is connected to the input terminal of the trigger circuit 80. The main discharge tube 16
A main capacitor 9 for storing luminous energy is connected in parallel to the main capacitor 9, and a known trigger circuit 10 is connected to the trigger electrode thereof. On the other hand, the second output terminal of the trigger circuit 10 is connected to the gate of the main thyristor 18 and a resistor 17 connected to the gate. 15 and 16 are resistors that form a charging path for the commutation capacitor 14, and among these resistors, the resistor 15 is connected to the sub-thyristor 19 for interrupting the main thyristor.
It is also connected to the anode of 20 is a resistor connected to the gate of the sub-thyristor 19, 21.22 is a resistor for a voltage dividing circuit connected in parallel to the main capacitor 9 to detect the charging voltage of the main capacitor 9, and 26 is a base. is connected to the output terminal of an OR gate 99 (described later) via a resistor 25, and the collector is connected to the voltage dividing circuit. 25 is a phototransistor that receives reflected light from an object (not shown); is connected to a constant voltage power supply 24 and a capacitor 57 for distance measurement. Reference numeral 50 denotes a comparator connected to the output terminals of the voltage dividing circuits 21 and 220, and the negative input terminal (→) of the comparator 50 and the negative input terminal (→ are constant voltage terminals in order to receive the reference voltage from the constant voltage power supply 24). It is connected to the output terminal of the power supply. 53 is a light emitting diode (hereinafter referred to as LFiD) connected to the output terminal of the comparator 50 via a resistor 52 in order to indicate the completion of charging of the main capacitor 9; 54 is the camera 9 ( A buffer circuit is connected to the connection terminal a connected to the fil connection terminal, and the output terminal of the circuit 54 is connected to the positive input terminal ( 41 is connected to the terminal a through a resistor 56, the base of the transistor 410 is connected to the output terminal of the comparator 50 through a resistor 55, and the emitter is connected to the terminal a of the battery. 1 negative electrode.

On the left side of the figure, an element 5-8 connected in series with the switching transistor 62 is a capacitor forming the first timing circuit of the photometry circuit in the flash amount control circuit, and an element 59 connected in series with the switching transistor 63 is a flash light amount control circuit. The element 60 connected in series with the switching transistor 64 and the second capacitor forming the second timer circuit of the '6111 optical circuit of the amount control circuit forms the third timer circuit of the photometry circuit for flash amount control. 3 capacitors, these medium capacitances 58 to 60 have discharge resistances of 142° and 143.14°.
4 are connected. 65, 66, and 67 are base resistors connected to the respective bases of transistors 62, 65, and 64; and 68 is a base resistor connected to the bases of transistors 62, 65, and 64, and 68 is a base resistor connected to the base of each of the transistors 62, 65, and 64. npn) run risk, 69 is a resistor connected to the base of transistor 68,
75, 74, and 75 are comparators for selecting the dimming level, that is, the aperture value to be used; 70, 71, and 72 are reference voltage supply resistors connected to these comparators 73 to 75; and 61 is a film to be set. Resistors 76 to 78 whose resistance values are varied depending on the sensitivity are connected via resistors 65 to 67 in order to make any one of transistors 62 to 64 conductive in synchronization with the generation of a light emission trigger signal to be described later. AND gates connected to the bases of each of the transistors 62 to 64; 80 an OR gate connected to the base of the switching transistor 68 via an inverter 79 and a resistor 69; 81 a light emission stop signal generated from the comparator 73; AND gates 82 to 84 are connected between the comparator 73 and the sub-silicon 19 to guide the dimming level A/selection (ij, that is, the aperture value selection signal) generated from the comparators 73 to 75. The output terminal of the gate 82 is connected to the gate of the thyristor forming the latch circuit 85, and the output terminal of the gate 86 is connected to the gate of the thyristor forming the latch circuit 86. ,
The output end of gate 84 is connected to the gate of a thyristor forming latch circuit 87. 85 to 87 are the latch circuits each formed of a thyristor as described above, and the anode of the thyristor forming the latch circuit 85 is the comparator 5.
1, and its cathode is connected to the base of a transistor 113 via a resistor 110. Further, the anode of the thyristor forming the latch circuit 86 is connected to the output terminal of the comparator 51, and its cathode is connected to the base of the transistor 114 via the OR gate 88, the AND gate 160, and the resistor 111. Furthermore, the anode of the thyristor forming the latch circuit 87 is connected to the output terminal of the comparator 51, and its cathode is connected to the OR gate 8.
Connected to 9. 90-95 are inverters, 105-1
07 is connected to AND gates 94 through resistors 101 through 103.
Light emitting diodes (LEDs) connected to 96 indicate the selected dimming level, or in other words the aperture value, prior to the main light emission. 108 is an inverter connected to AND gate 109, 1tS port, 110-1
12 is a base resistor connected to the base of the run risks 113-115, 116-118 are resistors for generating a voltage according to the selected aperture value, 119 is a resistor, and 120 is the resistor 116-118. resistors 121 for forming a voltage dividing circuit are connected in parallel to each of the buffer circuits 5 and 5;
A buffer circuit is connected to the connection point of the resistors 119 and 120 that divides the output of the circuit 4, and the non-inverting input terminal voltage is outputted as is at its output terminal. 122 is a comparator that adds up the open F-number signal of the lens supplied from the camera side through the terminal, and 125 and 126 are resistors for forming a voltage dividing circuit for supplying a reference voltage to the negative input terminal of the combalator 122. , 125 is an operational amplifier whose non-inverting input terminal is connected to the output terminal of the buffer circuit 121 and a resistor 124 is connected between the output terminal and the inverting input terminal, and the non-inverting input terminal is connected to the non-inverting input terminal. Voltage is generated as is.

the comparator 122, the bleeder resistor 125,
126 and the amplifier 123 constitute a detection circuit that detects the open II'MO information of the lens on the camera 2 side. The terminal is connected to an open FNo information source on the camera side, and the detection circuit is configured to detect the open FNo of the lens by detecting the value of impedance 2 of the open FNo information source. The comparator 122 outputs LL when the aperture FNo of the lens is smaller than the specified value, that is, the lens is lower than the aperture value, and outputs HL when the lens has a lower aperture value. Output.

127 is an inverter connected to the synchro terminal C for the light emission trigger signal and the input terminal of the AND gate 152;
1 is a monostable multivibrator (hereinafter referred to as a one-shot circuit) connected to the OR gate 80; 97 and 9B are AND gates; 104 is an underexposed Yoshikawa LED connected to the OR gate 99 via a current limiting resistor 100; is a terminal to which a constant voltage is supplied from the camera side when the camera release button is pressed down to the first stroke position, and this constant voltage is used to send out a shooting mode switching signal or shutter speed switching signal to the camera side as described later. , bill, a terminal that transmits the voltage corresponding to the selected aperture value signal from the strobe side to the camera side, and also transmits the open aperture value signal of the photographing lens used from the camera side to the processing circuit of the strobe. , C are known synchro terminals, and d is a ground terminal.

Next, in the above configuration, when the electrolytic erosion switch 2 is closed, the DC-DC converter 5 and the constant voltage power supply 24 start operating, and charging of the main capacitor 9 and the sub-capacitor 6 via the transistor 140 is started. . When the charge level of the main capacitor 9 reaches a predetermined value and the output level of the comparator 50 is reversed from a low level (hereinafter referred to as LL) to a high level (hereinafter referred to as HL), the LED 5S lights up and the main capacitor 9 is charged. At the same time as indicating that the charging has reached a predetermined level, a high level voltage is applied to the base of the transistor 41, and the transistor 41 becomes conductive.

At this time, if the voltage is set so that the Zener diode 143 becomes conductive, the transistors 142 and 141 become conductive, and the transistor 140 stops charging the sub capacitor 6 without interruption.

However, even after the LED 55 turns on, the amount of charge in the main capacitor 9 exceeds a predetermined level, and the charge is still sufficient to match the power supply 1.
! The amount increases to L amount. Next, the photographer presses the shirt release button (not shown) to the first stroke position (at this position, the shutter release or the aperture adjustment operation of the photographic lens does not start, but only the side light circuit, display circuit, etc. in the camera is activated). When the switch is pressed down to the point where it only starts operating, a constant voltage is applied to terminal a via the hot shoe of the camera, so the transistor 41 is reversed to a conductive state.
The mode of the shutter speed control circuit in the camera is switched from natural light photography mode to flash photography mode. At the same time, the constant voltage generated at the terminal a is also applied to the positive input terminal (G) of the comparator 51 via the buffer circuit 54, so the output level of the comparator 51 is inverted from LL to HL, and the one-shot The circuit 150 is triggered and the circuit 130 is triggered for a preset time 12-10.
For example, an output voltage of several tens [μB] is generated. Therefore, the trigger circuit 8 is triggered at the same time as the pulse is generated from the one-shot circuit 130, and generates a trigger pulse for triggering the sub-discharge tube 8 from its output terminal.

At this time, the auxiliary capacitor 6 is charged to a voltage capable of emitting light, so when a trigger pulse is given from the trigger circuit 8, a current flows from the capacitor 6 to the auxiliary discharge tube 7.
Group 1 is Nakagami-zu 4 → Preliminary light emission begins.

On the other hand, the pulse from the one-shot circuit 130 is also applied to the AND gates 82 to 84 and the OR gate 80, so the AND gates 82 to 84 are in a standby state, and the transistor 68 is turned off via the inverter 79 and the resistor 69. The short-circuit of the pressure capacitor 57 is released, and the production process h starts at the same time as the start of the photometric preflash for the 1illll distance photometry circuit.At this point, the light emission trigger signal of the synchro terminal CKLJJ is not applied. Since there is no one-shot circuit 131, the one-shot circuit 131 does not operate, and the AND circuit 7
6-78 have their gates closed. Therefore, the transistors 62 to 64 all maintain a non-conducting state, and the dimming capacitors 58 to 60 are all in the non-operating μ'Ib state. That is, only 57 integral capacitors are operating.

When the light from the discharge tube 7 reflected by the subject upon the start of preliminary light emission enters the phototransistor 23, the output voltage of the ranging capacitor 57 increases with the passage of time in accordance with the photocurrent flowing through the phototransistor 23. Furthermore, even after the discharge tube 70 stops emitting light, the charging voltage of the capacitor 57 increases by one level depending on the intensity of natural light illuminating the subject and its background.

The charging voltage of the capacitor 57 during the distance measuring process is latched as distance information by the latch circuits 85 to 87 when the output level of the one-shot circuit 130 is inverted to LL after about several tens of μB from the start of preliminary light emission. Charge 1 of capacitor 57! If only the comparator 75 becomes HL due to the voltage, only the output level of the latch circuit 87 becomes the output level, so the OR gate 89 and the AND gate 10
Only the citran lister 115 whose output level at each output terminal of 9 is HL is conductive, and the resistor 118 is connected in parallel to the resistor 120. At this time, since a constant voltage is applied to the resistors 119 and 120 from the terminal a via the buffer circuit 54, the aperture value 'P1, for example, ? When the resistor 118 for setting 2.0 is connected in parallel to the resistor 120, the potential at the positive input terminal of the buffer circuit 121 drops according to the resistance value of the resistor 11B connected in parallel, and The air pressure at the non-inverting input end of is also lowered accordingly. As a result, to output the terminal, set the aperture value of camera 2's photographing lens to II'1.
A small voltage is generated.

Further, when the OR gate 89 becomes IIL as described above, the AND gate 78 and the transistor 64 become in a state where they can become IIL and conductive, respectively. That is, the above-mentioned aperture value P1 can be set in the flash amount control circuit of the auto strobe.

Furthermore, when the OR gate 89 becomes ILL as described above, the output of the comparator 51 is HL and the output of the latch circuit 86 is LL, so the output of the AND gate 96 is also ILL, and LE.
I) 105 is lit, and the aperture of the photographing lens of camera 2 and the light control level (aperture value) of the strobe are set to the above-mentioned aperture value F1.
Inform the photographer in advance that the camera will be adjusted accordingly.

After performing the preliminary flash as described above and confirming that the preliminary (lift firing) C has been performed, that is, the operation for setting the light control level of the photographic lens and strobe has been performed, press the shirt release button described above. When pressed down to the second stroke position, a mirror (not shown) rises as described later, and the aperture diameter of the photographing lens (not shown) is determined based on the aperture value information predetermined by the preliminary flash described above. Ru.

Furthermore, after these operations and other known operations as described below are performed, the shutter (not shown) is fully opened and the synchro contact (
(not shown) is activated, the synchro terminal C is connected, and the AND gate 132 becomes HL.
and the one-shot circuit 131 is triggered,
The one-shot circuit 151 generates the HL signal for the time required for flash photography, for example, 5 to 6 (ms). Therefore, the transistor 68, which had been conductive in synchronization with the falling edge of the signal from the one-shot circuit 130, is again inverted to a non-conductive state, and the photometric circuit of the dimming circuit is inverted to an operable state. Also, the one-shot circuit 1! It i≧ et al. (
Main discharge tube 1 to trigger No.
Electrical energy is supplied to the main canister 9 by a known method, and the discharge tube 15 generates a flash of light that illuminates the subject. In this way, main light emission is started, and when the reflected light from the subject due to the main light emission enters the phototransistor 23, the capacitor 57 of the distance measuring photometry circuit and the capacitor selected at the time of preliminary light emission, for example, the capacitor 6
Charging starts at 0. And these capacitors 57.
When the charge level of 60 rises to a predetermined level and the comparator 75 is inverted to HL, the output of the AND gate 81 becomes H.
Since the light is reversed to 1, the Zyristor 19 is triggered and the main light emission is interrupted in a known manner, and flash photography is performed.

At this time, even if the amount of charge in the main capacitor 9 is not sufficient after the LliD 55 is turned on, appropriate exposure strobe photography is performed as in the conventional strobe device.

Therefore, according to this embodiment, the Zener diode 14
3, since the amount of charge in the sub capacitor 6 is kept constant, the amount of light emitted at the time of pre-flash is - in hot weather.The amount of light emitted during the pre-flash changes as the charge level of the main capacitor changes, and is set on the photographic lens. Even when the aperture value changes, the display indicating whether the subject is within the linked distance range does not change.

In this embodiment, a Zener diode 143. ) run lister 140, 141, 142, resistor 144, 145,
146, 147, and 148 to keep the charged amount of the sub-capacitor 6 constant.In addition, a diffusion surface such as a liquid crystal is provided on the front of the sub-discharge tube, and the voltage applied to the liquid crystal is connected to the capacitor of the strobe device. The amount of pre-emission light irradiated onto the subject may be made constant in accordance with the voltage.

As described above, according to the present invention, there is a display means for indicating that flash light emission is possible, and a pre-flash is performed prior to flash light emission during shooting, and the level of light reflected from the subject of the pre-flash is detected. and selects an appropriate light control aperture value according to the reflected light level, and controls the aperture value of the photographing lens using the aperture value, or determines whether the subject is within the interlocking range. The display flash device is equipped with a control means for keeping the light emission amount of the pre-flash constant from at least the time when the display means indicates that the flash light emission is possible. It is possible to prevent the display of the interlocking range from changing when the aperture wheel changes, and to make the user feel that the operation of the flash device is unstable when taking pictures using the strobe device. <It has improved operability compared to the conventional flash device, and l) It is highly effective.

[Brief explanation of drawings]

FIG. 1 is a circuit connection diagram of an embodiment of the present invention. 6... Sub-capacitor 7...Sub-discharge tube 9...Main capacitor 16... Main discharge tube 143...Zener diode Applicant: Canon Co., Ltd.

Claims (1)

[Claims] It has a display means that indicates that flash emission is possible, performs pre-flash prior to flash emission during shooting, detects the level of reflected light from the subject of the pre-flash, and adjusts the appropriate level according to the reflected light level. In a flash device that selects a light control aperture value and controls the aperture value of a photographing lens using the aperture value or displays whether or not the subject is within the interlocking range, at least the display means 1. A flash device comprising a control means for keeping the amount of light emitted in a pre-flash constant after a display indicating that a pre-flash light emission is possible.