JPH04351Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] Industrial field of application The present invention relates to a flashlight used for photography, and in particular to a flashlight used for TTL photometry cameras.

Prior Art A flashlight emitter emits light by discharging a discharge capacitor with a discharge tube. The exposure conditions for photography using this flashlight emitter are independent of the shutter speed, and the aperture is determined only by the distance to the subject depending on the amount of light from the flashlight emitter. Modern flash devices are designed to automatically control the amount of light emitted by a photometric circuit using photosensitive elements such as phototransistors so that the amount of light emitted is appropriate for the aperture set in the camera. Conventionally, this photometric circuit was built into the flashlight and was unrelated to the photometric circuit inside the camera, but in recent years, the photometric circuit inside the camera has been used to measure the amount of light emitted by the photometric signal from the camera. I started to take control. Among them, the so-called TTL photometry method, which measures the light reflected from the camera's film surface, is the most desirable for controlling the light amount of a flashlight. This is because it is sufficient to simply operate the discharge stop circuit of the discharge tube using the output signal of the photometry circuit of the camera.

However, when taking pictures using a flashlight, if there is only one flashlight, a strong shadow will be created behind the subject, resulting in an unnatural photograph that looks like it was taken with a flashlight, which is undesirable. Therefore, advanced lighting technology is required that synchronizes two or more light emitting devices to emit light and illuminates the subject from various angles to eliminate shadows or create natural shadows.
In this case, determining the aperture of the camera becomes difficult. This is because when a plurality of flashlight emitters are used to emit light, it is extremely difficult to calculate the setting value of the aperture. Therefore, in this case as well, it is extremely desirable to use the TTL photometry camera and control the amount of light emitted by all the light emitters using the output signal from the photometry circuit.

Problems that the invention aims to solve However, the flashlights used in conventional TTL metering cameras are generally not designed to allow multiple flashlights to be used at the same time. Even if it is possible to use multiple flash units, they simply fire at the same time and stop at the same time, and adjusting the light output ratio requires adjusting the position of each flash unit to the subject. There was nothing I could do but change it. It is extremely difficult to determine the ratio of the amount of light emitted by changing the distance from each light emitter to the subject.

The present invention has been made with these points in mind, and provides a flashlight for multiple flashes that can change the ratio of the light emission amount between the flashlight and the flashlight used in a TTL photometry camera. The purpose is to

[Structure of the invention] Means for solving the problem As is well known, the flashlight used in TTL photometry cameras has a synchro terminal, a ground terminal,
It has three terminals including a photometry output terminal. Therefore,
The flashlight for multiple lights of the present invention also has terminals connected to the three terminals, respectively. Furthermore, in addition to the normal light emitting circuit and light emitting stop circuit, the flashlight emitter of the present invention includes a first photometry circuit that starts operation when a pulse is applied to the synchro terminal and stops operation when a pulse is applied to the photometry output terminal; and a second photometric circuit that outputs a stop signal to the light emission stop circuit when the measured value reaches a preset value corresponding to the photometric output of the first photometric circuit. It is something.

Function: There are two methods of emitting light from the flashlight for multiple lights of the present invention. Specifically, there are two methods: a method in which the main flash unit directly connected to the camera emits light simultaneously with a synchronization signal, and a method in which the main flash unit emits light after the main flash unit stops emitting light. The choice between them is simply a matter of design.

First, a case where the main flash light emitter emits light simultaneously will be explained. When the camera's shutter is turned off, the synchro terminal is grounded and the main light emitter and main light emitter emit light. At the same time, the first photometric circuit operates. When a pulse is applied from the camera to the photometry output terminal, the main light emitter stops emitting light. However, since the light emission stop circuit of the multiple light emitter is connected to the second photometric circuit and not connected to this terminal, light emission continues. The pulse to the photometric output terminal stops the operation of the first photometric circuit. At the same time, the second photometric circuit operates. When the photometric value reaches a value equal to a ratio preset by the user with respect to the output of the first photometric circuit, an output is output from the second photometric circuit to operate the light emission stop circuit and stop the light emission. Therefore, the second
By changing the timing at which the output of the photometric circuit is output (the time taken to reach a certain proportion of the amount of light obtained by the first photometric circuit), the ratio of both light amounts can be selected. It will be easily understood that the multiple light emitters, which emit light after the main light emitter stops emitting light, operate in the same manner as described above, with no particular difference other than the difference in the light emission timing.

In addition, when using the flashlight for multiple flashes of the present invention, the timing at which the output pulse is output to the camera's photometric output terminal must be adjusted so that it is output when the camera is under 1 or 2 apertures by adjusting the exposure adjustment means installed on the camera. Must be set.

Embodiment FIG. 1 shows an example of using the multiple flash unit 1 of the present invention, which is configured to be connected to a main flash unit 3 attached to a camera 2 with a cord 4. This camera 3 is of the TTL photometry type and has a photometry output terminal C in addition to the synchro terminal A on its shoe 2a. Note that the ground terminal B utilizes the entire shoe 2a.

As shown in FIG. 4, the main flash unit 3 is a well-known device provided with a socket 5 into which a plug (not shown) of the cord 4 of the multiple flash unit 1 is inserted. There is no particular change in the circuit, and as shown in the figure, the main capacitor 7 is charged with the voltage boosted by the DC-DC converter 6 and discharged by the discharge tube 8 to emit light. It controls the amount of light emitted by turning off the connected SCR9. The terminals A1 and B are connected to the terminals A, B, and C of the camera, respectively.
1 and C1 are provided, and a trigger circuit 10 for starting discharge of the discharge tube 8 is activated when a pulse of ground potential is applied to the synchro terminal A1, and a positive pulse is applied to the photometry output terminal C1. It is configured to turn off SCR9 when . These circuits are so well known that no further explanation is necessary. In short, it is sufficient that the main flashlight emitter 3 emits light when receiving a pulse at the terminal A1 (grounded) and stops emitting light when it receives a pulse at the terminal C1.

The electrical circuit diagram of the flashlight emitter 1 for multiple lights according to this embodiment is as shown in FIG. In this embodiment, the main light emitter 3
It emits light after it stops emitting light. A plug attached to the tip of the cord 4 and inserted into the socket 5 has terminals A2, B2, and C2, which are respectively connected to terminals of the same alphabet. The main capacitor 11 and discharge tube 12 are the same as described above, and the voltage of the power supply 14 is increased by a DC-DC converter 13. The trigger circuit 15 for starting the discharge of the discharge tube 12 is activated by turning on the SCR 16 as in the conventional case, and the SCR 17 inserted to stop the discharge of the discharge tube 12 is activated by the operation of the thyristor 18 as in the conventional case. It is connected in such a way that it is turned off. These light emission and light emission stop circuits themselves may be conventional ones.

In this embodiment, the gate of the SCR 16 is connected to the terminal C2, and the gate of the thyristor 18 is connected to the second terminal described later.
It differs from ordinary ones in that it is connected to the output section of the photometric circuit.

Transistor 1 with emitter connected to power supply 14
9 is connected to terminal A2 via a resistor. The collector of this transistor 19 is connected to the collector of a phototransistor 20, and the emitter of this phototransistor 20 is connected to two analog switches 21 and 22. Further, resistors 24 and 25 are connected to the collector of the transistor 19.
A transistor 23 whose base is connected to the terminal C2 via the terminal C2 is connected thereto. The gates of the analog switches 21 and 22 are connected to this transistor 2.
One is directly connected to the collector of No. 3, and the other is connected via an inverter 26. Analog switch 21 is connected to an integrating capacitor 27, and analog switch 22 is connected to an integrating capacitor 28. These capacitors 27 and 28 have the same capacity. The voltage of capacitor 27 is applied to amplifier 29
The divided value is applied to the amplifier 31 via the resistor 30 . The resistor 30 is a variable resistor, and the amplifier resistor 32 also uses a variable resistor. These resistors 30 and 32 can be operated from outside the light emitter to change their resistance values, and around the operation knob 33 there are
There are scales of 1, 1.5, and 2. Each number represents an aperture, with 1 being 1 aperture and 2 being 2 apertures. The above amplifier 3 is connected to the inverting input of the comparator 34.
1, the voltage of the capacitor 28 is connected to the non-inverting input. That is, capacitor 28
The amount of light measured by the capacitor 27 is compared with the amount of light measured by the capacitor 27, and when the voltage of the capacitor 28 reaches the value obtained by increasing or decreasing the values of the resistors 30 and 32 using the knob 33, an output is output from the comparator 34 and the thyristor 18 is operated. It's summery.

In the above embodiment, the phototransistor 2
0, an integrating capacitor 27, and an amplifier 29 constitute a first photometric circuit, and a phototransistor 20, an integrating capacitor 28, and a comparator 34 constitute a second photometric circuit.

The operation of the above embodiment will be explained below. It is assumed that the exposure conditions of the camera 2 are set to be one aperture under. Thereby, the knob 33 is also adjusted to the scale 1 position.

After the main capacitors 7 and 11 are charged, when the shutter of the camera 2 is turned off, terminal A is short-circuited with terminal B. Therefore, the trigger circuit 10 of the main light emitter operates and emits light. At the same time, the transistor 19 of the flashlight emitter 1 for multiple lights is turned on, one analog switch 21 is turned on, and the phototransistor 20 is turned on.
Then, photometry using the integrating condenser 27 is started.
Since the gate of the SCR16 is connected to the terminal C2, the multiple flash unit 1 does not emit light.

The light is measured by a photometering circuit (not shown) of the camera 2, and a pulse is applied to the terminal C when the exposure is one aperture below the proper exposure. Therefore, the main flash emitter 3 stops emitting light. The amount of light at this point is one stop less than the appropriate value. At the same time, since a pulse is applied to terminal C2, SCR16 is turned on, and transistor 23 is also turned on. When the SCR 16 is turned on, the discharge tube 12 discharges and emits light, and when the transistor 23 is turned on, the analog switch 21 is turned off and the analog switch 22 is turned on. When the analog switch 21 is turned off, the brightness of the subject when the exposure is one stop below the proper exposure is stored in the capacitor 27 as a voltage. The high impedance of amplifier 29 maintains that voltage. This voltage is then applied across the resistor 30. resistance 3
The amplified voltage value according to the value set by the knob 33 of 0 and 32 is applied to the inverting input of the comparator 34.

The phototransistor 20 converts the reflected light from the object of the discharge tube 12 into an electrical signal, and the capacitor 28 is charged with the electrical signal. The value is the comparator 3
When the voltage applied to the inverting input of 4 is reached, the comparator 34 outputs an output and the thyristor 18
Turn on to stop emitting light. In this embodiment, the amplification by the resistors 30 and 32 is achieved by the capacitor 27.
The voltage is set to be equal to the voltage of In other words, if you set the camera's exposure adjustment to 1 stop under and set the knob to scale 1, the main light emitter 3
and the multiple light emitter 1 have the same amount of light. Also, if you set the camera's photometry circuit to 2 stops under and set the scale of the knob 33 to 2, the resistor 3 should be set so that the light intensity of the multiple light emitter will be 3 compared to the light intensity of the main light emitter of 1.
0 and 32 are set. Similarly, when the aperture is set to half aperture and 0.5, a voltage of approximately 40% of the voltage of the capacitor 27 is applied to the non-inverting input of the comparator 34, and when the light intensity reaches approximately 40% of the light intensity of the main light emitter. Resistors 30 and 32 are set so that discharge of the discharge tube 12 is stopped.

In this way, both light emitters provide an appropriate amount of light, and the light amount ratio between the main flash light emitter 3 and the multiple light emitter 1 can be set arbitrarily.

[Effects of the invention] As described above, according to the invention, it is possible to perform multi-flash photography using the photometry of a camera using the TTL metering method, and to perform desired lighting by arbitrarily changing the ratio of the amount of light emitted from each flash. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the state of a camera using the present invention, Fig. 2 is a circuit diagram of an embodiment of the invention, Fig. 3 is a plan view of the camera shoe, and Fig. 4 is the main part of the embodiment. Perspective view of the flash section of the flashlight emitter, No. 5
The figure is a plan view of the knob of this embodiment. 1...Flashlight emitter for multiple lights, 2...Camera, 3...
...Main flash emitter, 20...Phototransistor, 2
1, 22...Analog switch, 27, 28...
Integrating capacitor, 29, 31...Amplifier, 34...
…comparator.

Claims (1)

[Claims for Utility Model Registration] Used by connecting to a flash emitter that emits light when a pulse is applied from the camera to the synchronization terminal, and stops emitting light when a pulse is applied from the camera to the photometry output terminal. It has a synchronization terminal, a photometry output terminal, and a ground terminal connected to the above-mentioned synchronization terminal, photometry output terminal, and ground terminal of the flashlight emitter, and further includes a discharge tube and a pulse terminal to the photometry output terminal. A trigger circuit that starts the discharge tube to emit light; a first photometry circuit that operates in response to a pulse to the synchronization terminal and stops operating in response to a pulse to the photometry output terminal; At the same time, a knob for controlling the output voltage of the first photometric circuit according to the set value, and a pulse to the photometric output terminal start operation, and the measured value is set by the knob for the output voltage of the first photometric circuit. a second photometric circuit that outputs an output signal when the control voltage reaches a specified control voltage; and a light emission stop circuit that uses the output of the second photometric circuit to stop the light emission of the discharge tube. Light emitter.