JPS58108521A - Two-light type automatic dimming and flashing device - Google Patents

Abstract

PURPOSE:To select the luminous quantity ratio between two luminous parts to obtain sufficient bounce illuminatting effect by using the light emitting time of the 2nd luminous part of a twin storoboscope as the prescribed level reaching time of photodetective quantity in the 1st luminous part. CONSTITUTION:When a synchrocontact 50 is closed, the 1st luminous part 15 for bounce illumination starts light emitting and the reflected light of a object is detected 38 and integrated (39 to 40). When the integrated value reaches a reference level set up by a potentiometer 45, the 2nd luminous part 30 for front illumination starts light emitting by an output from a comparator 46. When the integrated value reaches a proper exposure level, a thyristor 23 is connected by an output from a comparator 43 to start commutation and both the luminous parts turn off simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called twin strobe having two light emitting parts.

A strobe has been proposed that has two light emitting parts, one of which is used for bounce illumination, and the other light emitting part is used for frontal illumination (so-called catch light) by pointing directly at the subject. In such a twin strobe, it would be possible to freely change the light intensity ratio between the bounce lighting and the front lighting, and if the exposure level could be detected by the photometry circuit installed inside the strobe and the flash light intensity could be controlled, it would be possible to achieve the photographer's intention. This makes it possible to freely select the lighting contrast of the subject and take photos with a strobe with appropriate exposure. However, in a normal twin strobe, the two light emitting parts are made to emit light at the same time, and the strobe side measures the light reflected from the object, and when the appropriate exposure amount is reached, the two light emitting parts are stopped emitting light at the same time. In this case, if one of the two light emitting parts is used for bounce lighting by pointing diagonally upward, and the other is used for frontal lighting by pointing directly at the subject, bounce lighting has a weaker subject illumination effect, so simultaneous firing and simultaneous stopping will result. The lack of light from bounce lighting results in flat photos with almost no bounce effect. Therefore, the above-mentioned twin strobe with automatic light intensity adjustment that allows the user to freely select the light intensity ratio between bounce illumination and frontal illumination is highly desirable for photographers.

In view of the above, the present invention has been made with the object of making it possible to freely select the ratio of the amount of light emitted from the two light emitting parts in an automatic light control type twin strobe.

The present invention provides a first and second light emitting section, and a light emission stop circuit common to both light emitting sections that simultaneously stops light emission of the first and second light emitting sections when a proper exposure amount is reached by integrating reflected light from a subject. and,
Provided is a strobe comprising a trigger circuit that starts integrating light reflected from a subject at the same time as the first light emitting section starts emitting light, and causes the second light emitting section to start emitting light when the integrated value reaches an arbitrarily selected predetermined level. It is something to do. In the above configuration, the first
When the second light emitting part is used for bounce illumination and the second light emitting part is used for front illumination, the bounce illumination light is emitted first, and by that illumination, an arbitrary amount of light is obtained less than the proper exposure.
After that, front lighting is added to obtain proper exposure, and a sufficient bounce lighting effect can be obtained.

Next, the present invention will be explained in detail by way of examples. FIG. 1 shows a circuit of one embodiment of the present invention. 1 is a power supply battery, 2 is a power switch, 3 is a booster circuit, 4 is a rectifier diode, and 5 is a main capacitor. When switch 2 is closed, booster circuit 3
operates and outputs high voltage alternating current, which is rectified by diode 4 and charges capacitor 5 to, for example, about 300V. 15 is a xenon tube of the first light emitting section, and 30 is a xenon tube of the second light emitting section. 14 is a trigger transformer of the first light emitting section, which includes 5CR11, a resistor 12. Together with the capacitor 13, it constitutes a trigger circuit for the xenon tube 15. When the synchro contact 50 on the camera side is closed, the one-shot circuit 9 outputs an "H" level signal for, for example, lQmS, and this signal The thyristor 11 is made conductive and the xenon tube 15 is triggered. As a result, the first light emitting section starts emitting light. The “H” level signal from the one-shot circuit 9 is also applied to the base of the transistor 36 via the inverter 47.

Transistor 86 is normally conductive and cone capacitor 89
Alternatively, both ends of 4o are short-circuited, but the one-shot circuit 9 outputs an "H" level signal, resulting in a cutoff state. A phototransistor 38 receives reflected light from an object, and its output current is integrated by a capacitor 89 or 4o when the transistor 36 is cut off. That is, with the above configuration, the integration of the reflected light from the object is started at the same time as the xenon tube 15 starts emitting light due to the closing of the synchro switch. Capacitors are 39 and 40
The reason why there are two of them is to change the integration level according to the aperture setting of the camera. For example, when the aperture value is F2.8, switch 41 is switched to the capacitor 39 on the contact a side (state in the figure), and the In this case, switch to capacitor 4o on the contact side.

The light intensity integral value obtained by the capacitor 39 or 4o is compared with a reference level, which will be described later, applied to its "minus" terminal by the comparator 46, and when the light intensity integral reaches the reference level, the output of the comparator L'-146 is “
This signal is inverted to H” level and applied to the gate of 5CR28 via the OR circuit 48.
6. Together with the capacitor 27 and the lga transformer 29, it constitutes a trigger circuit for the xenon tube 30 of the second light emitting section.
When the output of the comparator 46 is inverted to "H" level, the second light emitting section starts emitting light. Note that the first light emitting section continues to emit light.

Here, the reference level applied to the comparator 46 is the output voltage of the constant voltage source 42 divided by a potentiometer 45 that can be adjusted by a slider.
The output voltage is set equal to the integrated voltage of capacitor 39 or 40 when proper exposure is obtained. Therefore, for example, the output from the slider of potentiometer 45 is 1/42.
/2, the comparator 46 indicates that the exposure amount (this is due to the bounce illumination of the first light emitting section) is 1 less than the proper exposure.
When the stage under is reached, it is reversed to “H” level and the second
This causes the light emitting section of to start emitting light.

The duration of “H” level output for one shot @9 is:
Since the time is set to be slightly longer than that required for the strobe to emit the full amount of light, the light amount integration by the capacitor 89 or 40 continues even after the second light emitting section starts emitting light, and the integrated value is also sent to the comparator 43 as well as the comparator 46. is being applied.

The output voltage of the constant voltage source 42 is directly applied to the "-" terminal of the comparator 48, and since the output voltage of the constant voltage source 42 is set at the appropriate exposure level as described above, the capacitor 39 or 40 is charged. When the voltage reaches the appropriate exposure level, the output of the comparator 43 is inverted to "H1 level". This "H" level signal is applied to the gate of SCR23 to make it conductive.19CR23 is a commutating capacitor 21.25 , diode 20.35, resistor 22.
51 constitutes a light emission stop circuit for both the first and second light emitting sections, and when proper exposure is obtained, the first and second light emitting sections are stopped. The xenon tubes 15 and 30 of the second light emitting section are simultaneously turned off.

This completes the explanation of the main structure and operation of the circuit shown in FIG. 1, and next some additional parts will be explained. 7.8 is a one-shot circuit connected in series, and 7 is triggered by the closing of the synchro contact 50 and outputs an "H" level signal for about 2 ms. 8 is triggered by the fall of the H level output of 7 and remains “H” for about 5 mS.
Outputs a level signal. That is, the circuit 8 outputs an "H" level signal with a delay of 9 mS after the first light emitting section starts emitting light.

Since this signal is applied to the gate of the 5CR 28 via the OR circuit 48, the second light emitting section is also caused to start emitting light by the output of the one shot circuit 8. That is, when the comparator 46 does not output an "H" level signal even after 9 mS has elapsed after the first light emitting section starts emitting light, the second light emitting section is triggered by the output of the one-shot circuit 8. This configuration is provided for the following reason. When shooting, when the reflectance of surrounding walls is low or the subject is far away, the illumination power of the bounce lighting is weak, and even if the first light emitting part emits all the light, the integral of the received amount of reflected light from the subject There may be cases where the value does not reach the reference level set in comparator 46.

In this embodiment, the first. Since the main capacitor 5, which is the energy source, is common to the second light emitting section,
If the first light-emitting part emits light independently until it reaches its full capacity, the second light-emitting part will hardly be able to emit light, and the photograph will be almost entirely based on bounce lighting, which will not be able to illuminate the main subject much. This will result in a backlit shot where there is no light. In order to prevent such a situation, after the first light emitting section emits light, the comparator 46 outputs an "H" level while the main capacitor 5 still has enough charge to allow the second light emitting section to emit a sufficient amount of light. If no signal is output, the second light emitting section is forced to start emitting light so that proper exposure strobe photography can be obtained in which the front of the subject is also illuminated.

5CR17 is for lighting the xenon tube 15 of the first light emitting section, and 5CR34 is for lighting the xenon tube 80 of the second light emitting section. Comparator 46 at the base of transistor 32
The output of is applied via an inverter 49. Here, as mentioned above, the comparator 46 is normally at "L" and the transistor 32 is normally in a conductive state, so the resistor 33 connected to the gate of the 5CR34 is kept at "L" unless the output of the comparator 46 becomes "H". has been shorted. The right side of the capacitor 21 is charged to a positive potential, and when the xenon tube 15 is triggered, the anode side of the 5CR 17 becomes a high potential, and the right side potential of the capacitor 21 is momentarily pushed up. This increased voltage is the capacitor 1
9. The voltage is applied to the gate of 5CR17 through the resistor 18°716 to make 5CR17 conductive and turn on the xenon tube 15. At this time, the output of the comparator 46 is "L"
, and the thyristor 84 remains cut off. Next, when the output of the comparator 46 is inverted to "H" level and the xenon tube 30 is triggered, the 5CR8
4 is transmitted through the diode 85, the potential on the right side of the capacitor 21 is momentarily raised, and this raised voltage is applied to the resistor 24.83.
Applied to the gate of SC:R34 through capacitor 25.

At this time, since the transistor 32 is cut off, 5C
R34 is made conductive and the xenon tube 3o lights up.

Light emission stops when the “H” level output of the comparator 43 is 5.
When the voltage is applied to the gate of CR28 and 5CR2f3 becomes conductive, the right side of the capacitor 21, which was at a positive potential, is lowered to 0 potential, and this capacitor 21 and the diode 20
．． This is done by pulling down the anode of 5CR17#34 to a negative potential via 85 and simultaneously blocking 5CR17*84.

FIG. 2 shows the front of the strobe device of the present invention, and 15 is the first
The xenon tube of the first light emitting part, 3, which is the same as shown at 15 in the figure.
0 is the xenon tube of the second light emitting section, and 38W is the light receiving window, inside which is the phototransistor 8 shown in FIG.
8 is placed.

Reference numeral 15R denotes a reflector for the xenon tube 15, and is designed so that, for example, the xenon tube 15 can be rotated about the axis e of the fist, so that the light projection direction of the first light emitting section can be arbitrarily adjusted diagonally upward. FIG. 3 shows the back side of the above-mentioned device, and 45B is a knob corresponding to the slider of the potentiometer 45 shown in FIG.
At the right end position of the scale in the figure, zero voltage is applied to the comparator 46 as a reference level, the second light emitting section starts emitting light at the same time as the first light emitting section starts emitting light, and when the proper exposure is reached, the first and second light emitting sections start emitting light. The two light emitting parts are turned off at the same time. As the knob 45B is moved to the left along the scale, the reference level increases, and the light emission ratio of the second light emitting section (front illumination) to the first light emitting section becomes smaller. 41S is the operation knob for switch 41 in Fig. 1. When the aperture of the camera is set to F2.8, the same knob is set to the side indicating F2.8, and when it is set to F5.6, the same knob is set to F5.6. Switch to the side marked with . 2S is the power switch knob.

The present invention's Suirobo (flash device) has the above-mentioned configuration and is an auto-adjustable two-lamp type strobe that can selectively adjust the light intensity ratio of the two lights, so the effect ratio of bounce lighting and front lighting can be appropriately set depending on the situation. Very good flash photographs can be obtained.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a front view, and FIG. 8 is a rear view. 15... First light emitting section xenon tube, 80... Second light emitting xenon tube, 38... Phototransistor for receiving reflected light from the subject, 89.40... Capacitor for light amount integration,
48, 46...Comparator, 11--SCR for first light emitting section trigger, 28...SC for second light emitting section trigger
R,23,, 1st. Stopping the light emission of both second light emitting parts 5CR0 Agent Patent Attorney Hiroshi Tsune Branch Collection 2 Figure 2

Claims (1)

[Claims] a first light-emitting section, a second light-emitting section, a light-emission stop circuit that simultaneously stops emitting light from both light-emitting sections, a light-receiving element that receives reflected light from a subject, and a first light-emitting section that synchronizes with a trigger of the first light-emitting section. It consists of an integrating circuit that starts integrating the output of the light receiving element, and a trigger circuit that triggers the second light emitting section when the output of the integrating circuit reaches an arbitrary selected level lower than a value corresponding to proper exposure. . A two-lamp automatic light control flash device, characterized in that the light emission stop circuit is activated when the output of the integration circuit reaches a level corresponding to proper exposure.