JPH0434133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a strobe tuning device for a camera, particularly a camera having a focal plane shutter.

Generally, a single-lens reflex camera uses a focal plane shutter, so in order to perform strobe photography, an X-ray point is provided to detect when the front curtain of the shutter is open. Since this X contact is mainly composed of a mechanical switch, it is inferior in reliability and has the disadvantage that timing adjustment is difficult. In order to solve this problem, a device has been proposed that starts measuring time electrically at the same time the leading shutter curtain starts running, and outputs a trailing shutter curtain running start signal and a strobe trigger signal after a preset time. (Refer to Japanese Patent Application Laid-open No. 55-9586).

It also receives the subject light through the photographic lens,
A camera body that emits a control signal to control the amount of light emitted by a strobe based on the amount of light received, and a dedicated strobe whose light amount is controlled in response to this control signal have been proposed. Even if a general strobe that does not have the function of receiving the control signal is attached to the camera body, the camera can be set to manual mode, and the aperture value for obtaining the appropriate exposure can be calculated from the film sensitivity and subject distance. If you adjust the shutter speed to the same value and set the shutter speed to the sync speed, you can take normal flash photography.

Therefore, when a regular flash is attached, the photographer must manually set the aperture value and shutter speed as described above, but if the photographer does not change the mode and remains in auto mode, There is a high possibility that you have not set this aperture value and shutter speed. Also, if you take a picture in auto mode, the general strobe does not accept the light intensity control signal from the camera body, so it emits a fixed amount of light, whereas the camera body controls the exposure in auto mode. , proper exposure cannot be expected.

The present invention has been made in view of the above-mentioned circumstances, and uses a trigger means using the above-mentioned timer.
A strobe that can take pictures with proper exposure even if a regular strobe is attached and is accidentally set to auto mode, and can also notify the photographer of the incorrect mode setting by not firing the strobe. The purpose is to provide a tuning device. An embodiment of a tuning device according to the present invention will be described. 1st
The figure is its circuit diagram. A negative power supply terminal -Vb is connected to one end of a resistor 12 via a switch 10. The switch 10 is a normally open switch and is closed in conjunction with depression of the release button. The other end of the resistor 12 is connected via a switch 14 to the positive power supply terminal Vcc. The switch 14 is a normally closed switch and is opened in conjunction with the start of travel of the front shutter curtain. switch 14 and resistor 1
The connection point 2 is connected to the reset terminal R of a binary counter 18 that counts the clock pulses output from the oscillator 16. The counter 8 is composed of N flip-flops and has N output terminals ₁ to _N.
Further, the connection point between the resistor 12 and the switch 14 is connected to the set end of the flip-flop 22 via the inverter 20, and is also connected via the resistor 24 to the set end of the flip-flop 22.
Connected to the base of the NPN transistor 26.
The emitter of the transistor 26 is connected to one end of a capacitor 28, and the capacitor 28 is connected to the negative power supply terminal -Vb via the switch 10.
The other end is connected to the collector of transistor 26, the anode of photodiode 30, and the inverting input terminal of differential amplifier 32. photodiode 30
is placed behind the camera's mirror in a position that does not obstruct the optical path to the film and receives reflected light from the film and the front curtain of the shutter. The cathode of photodiode 30 is grounded. The Nth digit output terminal _N of the counter 18 is connected to the base of a PNP transistor 36 via a resistor 34. The emitter of transistor 36 is connected to the cathode of photodiode 30, and the collector of transistor 36 is connected to the anode of photodiode 30 via resistor 38. One end of the constant current source circuit 40 is grounded, and the other end is connected to the non-inverting input terminal of the differential amplifier circuit 32 and connected to the negative power supply terminal - via the variable resistor 42 and the switch 10.
Connected to Vb. The output terminal of the differential amplifier 32 is connected to a light emission control terminal 44 and one input terminal of a NAND gate 46, and is also connected to one input terminal of a NAND gate 50 via an inverter 48.

The output terminal of NAND gate 46 is NAND gate 5
Connected to one input end of 2. NAND gate 5
The output terminal of 2 is connected to the base of an NPN transistor 56 via a resistor 54. transistor 5
The emitter of 6 is connected to the anode of the Zener diode 58 and the emitter of the NPN transistor 60, and is also connected to the negative power supply terminal -Vb via the switch 10. The collector of the transistor 56 is connected to the cathode of the Zener diode 58 and the collector of the transistor 60, and is also grounded via a trailing curtain locking magnet 62. The base of the transistor 60 is connected to the M-th digit output terminal _M of the counter 18 via a resistor 64.

The emitter of transistor 60 is grounded via resistor 66 and switch 68. The connection point between the resistor 66 and the switch 68 is connected to one input terminal of the NAND gate 70, and also connected to the other input terminal of the NAND gate 46, the other input terminal of the NAND gate 50, and one input terminal of the NAND gate 74 via the inverter 72. connected to. The output of the X digit of the counter 18 is the reset end of the flip-flop 22,
It is connected to the other input terminal of the NAND gate 70.
The output terminal of the NAND gate 70 is the NAND gate 52
is connected to the other input terminal of flipflop 2
The Q output terminal of 2 is connected to NAND via the inverter 76.
It is connected to a first input terminal of gate 78 . NAND
The output terminal of gate 50 is connected to the second output terminal of NAND gate 78.
Connected to the input end.

A dedicated strobe terminal 80 is connected to an input terminal of a detection circuit 82 . The output terminal of the detection circuit 82 is a resistor 84
It is connected to the base of the PNP type transistor 86 via. The emitter of transistor 86 is grounded, and the collector of transistor 86 is connected via resistor 88 and switch 10 to negative power supply terminal -Vb, and also via inverter 90 to the other input terminal of NAND gate 74. The output of NAND gate 74 is connected to the third input of NAND gate 78. The output end of NAND gate 78 is connected to one end of capacitor 94 via inverter 92. The other end of capacitor 64 is connected to the gate of thyristor 96. A resistor 98 is connected between the gate and cathode of the thyristor 96, and the cathode of the thyristor 96 is grounded.
The anode of 6 is connected to the tuning terminal 100. Ground terminal 102 is grounded. The above-mentioned light emission control terminal 44, dedicated strobe terminal 80, and tuning terminal 10
0. A ground terminal 102 is used for connection to a strobe device, which will be described later.

FIG. 2 is a circuit diagram of a dedicated autostroboscopic device attached to a camera having the tuning device shown in FIG. A negative terminal of high voltage power supply 104 is connected to one end of main capacitor 106 and one end of strobe tube 108 . The positive terminal of high voltage power supply 104 is connected to the anode of Zener diode 112 via switch 110. zener diode 112
The anode of is connected to the dedicated strobe terminal 80 via a resistor 113. zener diode 112
The cathode of is connected to the other end of the main capacitor 106, the cathode of the thyristor 114, and the ground terminal 102. The anode of thyristor 114 is connected to the other end of strobe tube 108 and one end of capacitor 116. The light emission control terminal 44 is connected to the input terminal of the light emission amount control circuit 118, and the light emission amount control circuit 1
The output end of 18 is connected to the other end of capacitor 116. The tuning terminal 100 is connected to the input end of the trigger circuit 120 , the output end of the trigger circuit 120 is connected to the trigger end of the strobe tube 108 , and the control end of the trigger circuit 120 is connected to the gate of the thyristor 114 .

FIG. 3 is a circuit diagram of a general strobe device that is not exclusive to this camera. Components that are the same as those in FIG. 2 are given the same numbers and their explanations will be omitted. That is, the strobe device shown in FIG. 3 cannot control the amount of light emitted, and the flash control terminal 44 and the dedicated strobe terminal 80
is not provided.

The operation of this embodiment will be explained below. First, the case where the dedicated autostroboscopic device shown in FIG. 2 is installed will be described. In this case, aperture-priority automatic exposure control is used, and by setting only the aperture, the shutter speed and flash output are automatically controlled.
Of course, this aperture setting is also done automatically according to the received light value. Although so-called programmable EE is also possible, only the aperture priority type EE will be explained.
The switch 68 functions as a switch for changing the shutter speed control mode, and is opened when the automatic mode is set and closed when the manual mode is set. That is, the open/closed state of the switch 68 is determined depending on whether the attached strobe device is a dedicated auto strobe or not. Here, the switch 68 is naturally open. The photographer first presses switch 11 on the strobe device.
Close 0. As a result, the main capacitor 106 is charged via the Zener diode 112. A Zener voltage is generated across the Zener diode 112, and this voltage is supplied to the camera-side detection circuit 82 via the resistor 113 and the dedicated strobe terminal 80. When the release button is pressed, switch 1
0 is closed and supply voltage is supplied to all circuits.
The detection circuit 82 detects the completion of charging of the main capacitor 106. The output signal of the detection circuit 82 becomes L level, and the transistor 86 is turned on. The H level collector signal of the transistor 86 is brought to the L level via the inverter 90 and the NAND gate 7
4, the output terminal of the NAND gate 74 is at H level. Since switch 68 is open, the output terminal of inverter 72 becomes H level. Before the leading shutter curtain runs, the transistor 26 is in a conductive state, so the capacitor 28 is not charged.
The terminal voltage of capacitor 28 is zero. Therefore, the output terminal of the differential amplifier 32 is at H level, and the output terminal of inverter 48 is at L level. NAND
Since both input ends of the gate 50 are at H and L, the output end is at H level. Also, before the shutter front curtain runs, the output terminal of the inverter 20 is at L level, so
Flip-flop 22 is set, and the output terminal of inverter 76 is at L level. Therefore, since one of the input terminals of the NAND gate 78 is at L level, the output terminal is at H level. NAND
Since the output end of the gate 78 is connected to one end of the capacitor 94 via the inverter 92, the thyristor 96 is in a non-conducting state and the strobe tube 10
8 is not emitted.

When the release button is pressed, the mirror is raised, and when the mirror has finished raising, the front shutter curtain starts running. When the switch 14 is opened in conjunction with the start of running of the shutter front curtain, the counter 18 is reset and the transistor 26 becomes non-conductive, so that the photovoltaic current capacitor 28 of the photodiode 30 is charged, and The terminal voltage gradually increases. When the switch 14 is opened, the output terminal of the inverter 20 goes to the H level. At this time, all output terminals of the counter 18 are at the H level, so the output terminal of the flip-flop 22 is kept at the H level. Therefore, the output terminal of NAND gate 78 is kept at H level, and thyristor 96 is not turned on.

The X-digit output terminal of the counter 18 is the time from when the counter 18 is reset, that is, from when the leading shutter curtain starts running until the running of the leading shutter curtain ends (1/60 in this embodiment). seconds)
As time elapses, the H level changes to L level. The flip-flop 22 is reset because its reset terminal goes to L level, and the output terminal Q changes to L level, so the output terminal of inverter 76 changes to H level. At this time, the amount of light received by the photodiode 30, that is, the charging voltage of the capacitor 28 is
If the variable resistor 42 has not reached a predetermined voltage, the output terminal of the differential amplifier 32 remains at the H level, so all three input terminals of the NAND gate 78 become at the H level. Therefore, the output terminal of the NAND gate 78 changes from H level to L level,
The output terminal of inverter 92 changes from L level to H level, and a positive pulse voltage is applied between the gate and cathode of thyristor 96. As a result, the thyristor 96 becomes conductive, the trigger circuit 120 of the strobe device is energized, and the strobe tube 108 emits light.

When the terminal voltage of the capacitor 28 reaches a predetermined voltage, the output terminal of the differential amplifier 32 changes to L level, the light emission amount control circuit 118 is energized, and the strobe tube 108 stops emitting light. At the same time, NAND
The output terminal of the gate 46 is at H level, and the output terminal of NAND gate 52 is at L level. Then, the transistor 56 is made non-conductive, the shutter trailing curtain locking magnet 62 is deenergized, the shutter trailing curtain is moved, and the shutter operation is completed.

In this way, the running of the shutter rear curtain is controlled at the timing when the amount of light received by the photodiode 30 reaches a predetermined value, but the shutter time cannot be shortened indefinitely for mechanical reasons. Furthermore, even when the subject is dark, if the shutter speed is set to an unlimited length, there will be problems such as not being able to take the next shot or increasing battery consumption, so it is necessary to set a certain limit on the shutter speed. The M-th digit output terminal _M of the counter 18 goes low after the shortest shutter time (for example, 1/1000 seconds) after being reset.
level, and the Nth digit output terminal _N is set to become L level after the longest shutter time (for example, 4 seconds). Therefore, when the _M output terminal is at the H level, even if the output terminal of the differential amplifier 32 goes to the L level and the transistor 56 is made non-conductive, the shutter trailing curtain will not run because the transistor 60 is still conductive. . Then, after the _M output terminal of the counter 18 becomes L level, that is, after 1/1000 seconds have passed since the leading shutter curtain was run, the trailing shutter curtain is run. in this way,
The shutter time is always longer than 1/1000 second. Further, when the _N output terminal of the counter 18 becomes L level, the transistor 36 becomes conductive and the differential amplifier 32
The output terminal of the capacitor 28 becomes L level regardless of the terminal voltage of the capacitor 28. Therefore, the transistor 56
becomes non-conductive and the rear shutter curtain runs.
That is, the shutter time will never be longer than 4 seconds.

On the other hand, if the amount of light received by the photodiode 30 reaches a predetermined value before the output terminal of the counter 18 becomes L level, the output terminal of the differential amplifier 32 becomes L level.
When the level changes, the rear shutter curtain is similarly run. At this time, since the output terminal of the NAND gate 50 is at the L level, the output terminal of the NAND gate 78 is always at the H level, the thyristor 96 is not conductive, and the strobe tube 108 does not emit light.

Next, a case where a strobe device is generally attached as shown in FIG. 3 will be explained. At this time, automatic exposure control is not possible, and the shutter speed is set to 1/60 seconds and the aperture is manually set to the value determined by the strobe's guide number. At this time, switch 68 is closed. Further, since a general strobe device is not provided with the light emission control terminal 44 and the strobe connection terminal 80, the transistor 86 is not conductive and the output terminal of the inverter 90 is at H level. However, since the switch 68 is closed, the inverter 7
The output terminal of 2 is at L level, and the output terminal of NAND gate 7
The output terminal of No. 4 is at H level, the same as when the dedicated auto strobe device is installed. Furthermore, since the output terminal of the inverter 72 is at the L level, the output terminal of the NAND gate 50 is always at the H level regardless of the level of the output terminal of the differential amplifier 32. Before the leading shutter curtain runs, flip-flop 22 is set, so the output terminal of inverter 76 is at L level, the output terminal of NAND gate 78 is at H level, and thyristor 96 is not conductive.

Even when the shutter leading curtain is run, the flip-flop 22 remains set as in the case described above.
When 1/60 second has elapsed since the shutter leading curtain started running, the output terminal of the counter 18 goes to L level, so the flip-flop 22 is reset, the thyristor 96 becomes conductive and the strobe tube 108 emits light as in the case described above. be done. Here, since the output terminal of the inverter 72 is at L level,
The output terminal of the NAND gate 46 is at H level.
At this time, the output terminal of the NAND gate 70 also becomes H level due to the output signal of the counter 18, so that the output terminal of the NAND gate 52 becomes L level. As a result, the transistor 56 is rendered non-conductive, and the trailing curtain of the shutter starts running.

Here, the operation when the switch 68 is opened due to an operational error will be described below. That is, even though the dedicated auto strobe is not installed, the changeover switch 68 remains set to auto mode, and the shutter speed is not set. Here, since the detection circuit 82 is not energized, the transistor 86 is in a non-conducting state, so the NAND
Both input ends of the gate 74 are at H level. Therefore, since one input terminal of the NAND gate 78 is at L level, the output terminal is always at H level.
This means that the thyristor 96 is never turned on and the strobe tube 108 is never illuminated. For this reason, normal EE photography is performed using natural light to ensure proper exposure. In addition, the photographer can detect mode setting errors, and by setting the manual mode, the calculated aperture value, and the synchronized shutter speed, it is possible to use a standard flash to take photos with a proper exposure. becomes.

As explained above, according to the present invention, even if a general strobe is attached and is accidentally set to auto mode, a photograph will be taken with proper exposure, and the photographer will be able to understand that it is a general strobe. It is possible to provide a strobe synchronization device that can switch the photographing mode and actively notify the necessity of setting the synchronization time and aperture value.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of a strobe tuning device according to the present invention, Fig. 2 is a circuit diagram of an auto strobe device exclusively for this camera, and Fig. 3 is a circuit diagram of a general strobe device not exclusively for this camera. It is. 10, 14...Switch, 18...Counter,
22...Flip-flop, 28...Capacitor, 30...Photodiode, 32...Differential amplifier, 44...Light emission control terminal, 62...Shutter rear curtain locking magnet, 68...Selector switch,
80... Dedicated strobe terminal, 96... Thyristor, 100... Tuning device, 102... Grounding terminal.

Claims (1)

[Scope of Claims] 1. A timer unit that starts a timing operation in response to the start of running of the front shutter curtain and outputs a first signal after a predetermined time required for the front shutter curtain to finish running; and an object that is photographed through a photographic lens. Receives reflected light from the front shutter curtain or film surface, continues outputting the second signal from when the shutter front curtain starts traveling until the amount of received light reaches a predetermined amount, and when the amount of received light reaches the predetermined amount. a light receiving means for deactivating the second signal; an auto mode for controlling the shutter mechanism according to the second signal outputted by the light receiving means; and a manual mode for controlling the shutter mechanism according to information manually set. A mode changeover switch that performs switching and a dedicated strobe that starts emitting light in response to a trigger signal and stops emitting light in response to deactivation of the second signal are installed, and detects the completion of charging of the main capacitor. , dedicated strobe attachment detection means that outputs a third signal; and when the mode changeover switch is set to auto mode, the trigger signal is not output when a general strobe is attached, and the first trigger signal is output when the dedicated strobe is attached. The trigger signal is output only when all of the signal, the second signal, and the third signal are output, and when the mode selector switch is set to manual mode, the trigger signal is output regardless of the second signal and the third signal. A strobe tuning device comprising: trigger means for outputting the trigger signal in response to only the first signal. 2. The strobe tuning device according to claim 1, wherein the timer means also serves as a timer means for outputting a signal that determines the shortest shutter time and longest shutter time of the shutter mechanism.