CA1157078A - Dual tube direct and bounce flash apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
ELECTRIC FLASH APPARATUS

This invention discloses an electric flash apparatus comprising a flash housing which consists of a first casing and a second casing, each of which is pivotably connected, a first flashing member having at least one flash tube and ar-ranged in said first casing, a second flashing member including at least one flash tube and arranged in the second casing, and a flash control circuit arrangement for controlling effectively quantity and a flash duration of flash light of said flash tubes.

Description

115707~3 .

EL~CT~IC FLASH APPARA~'US

The present invention relates to a flash apparatus, and more particularly to an electrlc ~lash apparatus.

BACKGROUND 0~ THE INV~NTION
In recent years, the flash apparatus has been widely em-ployed in various kinds of optical apparatus which requires light o~ the ~lash. Particularly, in the art of photography, artificial light is used to illuminate an object to be photo-graphed. One form of arti~icial light which into wide use is so-called electric ~laæh device. In such devices, a flash tube iæ provided in order to illuminate the object to be photographed.
l`he light from the ~lash tube can only be used to illuminate the object to take a picture. When the ~lash light ~rom a photoflash is used to illuminate the object to be photographed, light and darkness appear on the photographic object in case there is unevenness on the sur~ace of the photographic object.
~urthermore, when the ~lash light ~rom the photoYlash is em-ployed as a direct-light for illuminating the photographic object in a room or a photostudio, æhadow of the photographic object is ~ormed behind thereof and it is, there~ore, not so pre~erable to take a picture in a practical use.
In order to eliminate the disadvantages of the photo~lash device, it ks known to take a picture by using means for gene-rating bounce light. In taking a plcture by means of the bounce light, there are, however, still disadvantages that quantity of the light incidenting on the photographic object iæ lowered compared with the predetermined value particulatly when a re~lecting æurface such aæ a surface of celling is not ~,i 7~'7~3 so white, and that the photographic object can not be photo-graphed so good when there is the unevenness on the surface of the object to be photographed, because the reflected light from the object does not, in part, incident on a film of a camera.
To eliminate the above disadvantages, required are various kinds of high price devices such as, for example, a front light, an umbrella-shaped bounce light and a backlight for removing the shadow appearing at the background of the photographic object. This results in a package which is sufficiently bulky as to preclude its use in portable, as well as is costly and lmeconomical.
In accordance with a particular embodiment of the invention there is provided an electric flash apparatus.
The apparatus has a circuit for charging a main capacitor and a flash tube circuit actuated by the operation of a trigger circuit when an electric charge is stored on the main capacitor. Also provided are a plurality of flashing members, each of which includes at least one flash tube, and a flash control circuit arrangement for receiving light generated from the flashing members and reflected from an object to be photographed. The flash control circuit also converts the light to an electric energy and automatically controls flash-light quantity when the electric energy attains a predetermined value. The flashing members comprise a first flashing member adaptable to generate direct light with respect to the object to be photographed and a second flash-ing member adapt~ble to generate indirect light with respect to the object. Means are provided for making the incident direction of the second flashing member adjustable and means ~ - 2 -;

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are provided for adjusting flash light quantity such that the flash light quantity of the first flashing member is less than that of the second flashing member when the first and second flashing members activate.

;' `'' ~1570~8 BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a detailed circuit diagram of a control circuit arrangement of an electric flash apparatus according to the present invention;
Fig. 2 is a schematic view of an electric flash apparatus in accordance with the present invention;
~ig. 3 is an elevational-side view for explaining an oper-ation, when a bounce photographing is performed by using an electric flash apparatus in accordance with the present in-vention; -Fig. 4 is a graph æhowing a characteristic o~ the quantity of light produced from an electric flash apparatus in accordance with the present invention; and Fig. 5 is a graph showing a characteristic o~ the quantity of light and denoting an operation oi an electric ~lash appa- ;~
ratus according to the present invention.

DESCRIPTION OF THE PXEFERED EMBODIME~T OF THE INVENTION
Referring to Fig. 1 of the drawing, there is shown a greatly simplified electric flash apparatus in accordance with the present invention. The electric flash apparatus has a flash housing, generally designated by numeral 10 which consists of a first casing 11 and a second casing 12. The second casing ;
12 is pivotably connected to the iirst casing 12 by means of a connecting member 14. ~he connecting member 14 is constructed by a conventional ratch mechanism. The ratch mechanism is con-structed by a pin 14a which is fixed on the second casing 12 and which is pivotably engaged with the first casing 11, a ratch gear 14b which is fastened to the second casing 12 together with the pin 14a, a curved U-shaped plate spring 14c inserted ~57~78 into the first casing 11 and a enga~ing segment 14d which is provicled between the plate spring 14c and the ratch gear 14a.
Accorclingly, the second casing 12 is rotatable as is shown by an arrow 13 with respect to the ~irst casing 11. The ~irst 5 casing 11 is equipped with a light sensitive element 15 and a ~irst Plashin~ member 16 which includes a ~irst flash tube 17, on a surface thereo~. The second casing 12 is also equipped with a second flashin~ member 18 which includes a second flash tube 19. Accomodated in the i'lash housing 10 is a flash con-trol circuit arrangemellt which is constructed a~ shown in ~ig. 2.
As is best shown in Fig. 2, the flash control circuitarrangement comprises a power source circuit A, a electric charge Etoring circuit B for supplying the electrical energy to the ~lash tubes 1~ and 19, a trigger pulse generating circuit C
~or trig~ering the flash tube member, a ~lash tube circuit ~
~or generating a flash light, a switching circuit D for actua-tin$ the ~lash tube circuit E, a quenching circuit F for ex-tinguishing the flash tubes o~ the ~lash tube circuit E, a quench trig~er si~nal generating circuit G for actuating the quenching circuit F and a light-sensitive circuit H ~or actua-ting the quench trigger si~nal generating circuit F.
In more detail, the power ~ource circuit A include~ a battery 20, a manually operated switeh 21 and a resistor 22 con-nected in series with the battery 20 by way of the switch 21.
The electric charge storin~ circuit B comprises a main ~torage eapacitor 23 which i~ connected in parallel relationship to the battery 20 through the switch 21 and the resistor 22 and a charg-ing level indicating lamp in the form of a neon tube 25 which i9 conneeted in parallel with the main storage capacitor across a resistor 25. When the main storage capacitor 23 is c~arged up ~lS7~78 to a predetermined charging voltage, the neon tube 25 lumi-nesces and indicates the ready for flashing.
The trigger pulse generating circuit C includes a trigger resistor 26, a trigger capacitor 27 and a trigger transformer 28. In the trigger pulse generating circuit C, one terminal of the trigger resistor 26 is connected to a positive terminal of the battery 20 by way of the resistor 22 and the switch 21, One terminal of the trigger capacitor 27 is connected to the other terminal of the resistor 26 and an input winding 28a of the trigger transformer 28 is con-nected to the other terminal of the trigger capacitor 27, The switching circuit D includes a trigger capacitor 29, a transformer 30, a synchronizing switch 31 and a switch-ing element in the form of a first thyristor 32, a protecting resistor 33, a gate resistor 34, a capacitor 35 and a resistor 36. The trigger capacitor 29 is connected to the trigger resistor 26, and an input winding 30a of the pulse trans-former 30 is connected between the input winding 28a and capacitor 29. The synchronizing switch 31 is interposed between a juncture of the resistor 26 and the capacitor 27 and a juncture of the input windings 28a and 30a. The pro-tecting resistor 30 is interconnected between a negative terminal of the battery 20 and a juncture of the synchronizing switch 31 and the input winding 30a of the pulse transformer 30, An output winding 30b of the pulse transformer 30 is connected between a gate electrode and a cathode electrode of the first thyristor 32 through the gate resistor 34. The switch 31 is mounted on a camera, and is closed in syn-chronism with a camera shutter opening operation, enabling flash tube to be fired by the well-known operation of flash trigger circuit, The flash tube circuit ~ comprises a first ilash tube 1'7, a second ilash tube 19 and a current-limitting resistor 37 ~or restrictin~ flash current ilowing the iirst flash tube ~7.
The first ilash tube 17 is provided with a pair of rnain current conducting electrode 17a, 17b and a trigger electrode 17c which is positioned adjacent but external to the ilash tube 17. The second flash tube 19 is al~o provided with a pair of main current conducting electrodes l9a, l9b and a triggeI elec-trode l9c which is also positioned adjacent but external to the flash tube 19. As explained in the foregoing in Fig. 1, the first flash tube 1'7 is arranged in the iirst ilashirlg menlber 16 which is mounted on the surface o~ the iirst casing 11, and the second ilash tube 19 is arranged in the second flashing member 18 mounted on an end portion o~ the second cas~ng 12. One main current conducting electrode l9a of the second flash tube 19 is connected to one electrode of the main storage capacitor 23, and the other main current conducting electrode l9b iB connected to an anode electrode oi the thyristor S2 oi the switching circuit D. The trigger electrode l9c of the second flash tube 19 is connected to one terminal of an output winding 28b oi trigger transformer 28. One main current conducting electrode 17a is connected to the one electrode of the main storage capacitor 23 through the current-limitting re~istor 37, and the other main current conductlng electrode 17b ls connected -to the anode oi the thyristor -S2 together with the main current conducting electrode l9b oi the second ilash tube 19 and, thereiore, the electrode 17b and l9b are connected t~, th~ othe~ electrode o~
the main storage capacitor 2~ by way oi the f~r~ th.y~ 2.
.. 'rhe trigger electrode 17c of the Yir~t fla~æh tube 17 is connec to the output winding 28b O~ e ~F1gger trans~ormer 28 r .

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~lS7~1~8 together with the trigger electrode l9c of the second flash .:
tube 19, thence the first flash tube 17 and the second flash tube 19 are simultaneously triggered by the triggering signal from t.he triggering pulse generating circuit C.
T.here are certain criteria, in the flash tube circuit ~, that must be met in both flash tubes 17 and 19. To operate ef~ectively, the current to be supplied to the first fla~h tube 17 mu~t be a relatively low value compared with that to be sup-plied to the second flash tube 19, in order to make the quanti~
of the flash light generated from the ~irst flash tu~e 17 to smaller than that of the flash light from the second flash tube 19. 'l`o perform this requisition, the firæt flash tube 17 must have a relatively low impedance compared with the second flash tube 19. To provide such low impeda~ce, the first flash tube l'j 17 should have a low gass pressure and a short electrode spacing.
On the other hand, when the ~ir~t ~lash tube 17 has a low im-pedance compared with the second ~lash tube 19, an initiation of ~ :
flashing of the first flash tube 17 occurs earlier than that of the second flash tube 19. To supply such low current and to adjust the flash durations of the flash tubes 17 and 19, thecurrent-limitting resistor 37 is connected to the ~irst flash tube 17. Additionally, although the flash tube ci~cuit ~ em-ploys the resistor 37 a~ the current-limittin~ element, the in-vention is not limitted to thi~, and a chorked-coil ~ay also be ~:
employed.
The quenching circuit F includes a quench tube 38 for qu~nching the fiash tubes 17 and 19, a resistor 39, a commu-tation capacitor 40 and a commutation resistor 41. The quench tube 38 is connected to both electrodes of the main stGra~e capacitor 23 through the resistor 39. The commutation capaci-, -, . . , . :. ~ .
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~L15'7~)78 tor 40 is connected between a juncture of the resistor 39 and the quench tube 38 and the anode electrode of the thyristor 32, and the commutation resistor 40 is connected in parallel relation-ship to the thyristor 32 between the anode electrode and the cathode electrode thereof.
There are, of couræe, certain criteria that must be met in quench tube 38. To operate effectively, the quench tube 38 must have a ~urther low impedance compared with the second flash tube 19. The second flash tube 19 has a minimum impedance o~
typically 1.5 to 2 oh~s. Thus, the quench tube 38 should have an impedance near 0.~ oh~. To provide such low impedance, the quench tube 38 also should have a low gass pressure and a short electrode spacing. '~he electrodes 38a and 38b must be capable o~ carrying a very high current for short time. The tube 38 must be capable o~ bei~g triggered rapidly and easily into con-duction over the range which voltage of the ~lash -tubes 1'7 and 19 changes during the flash. The quench tube includes a trigger electrode 38c spaced midway between the two main electr~des 38a and 38b.
The quench trigger signal generating circuit G comprises a qugnch trigger transformer 42, two series connected resistors 3 and 44, a second switching element in the form of ~he thy-ristor 45 whose anode electrode i9 connected an lnput winding 42a o~ the quench trans~ormer 42, and a quenching capacitor 46 which is co~nected in parallel with the re3istor 44. An ou~put winding 42b of the quenching transformer 42 is interconnected be-tween the trigger electrode 38c of the quench tube 38 and a juncture of the input winding and the anode electrode o-f the thyristor 45.
The li~ht sensitive circuit ~ comorises a light sensitive ~'7~)'78 element in the form of a phototransistor 47, a capacitor 48 whose one electrode is connected to the positive electrode of the battery 20, a zener diode 49 connected between the capaci-tor ~8 and the photocell 47, a gate resistor 50 connected a gate electrode of the thyristor 45 and the photocell 47, paral-lelly connected resistor 51 and capacitor 52, and a protecting resistor 53.
A circuit constructed in accordance with the fore-going description operates as follows:
When the switch 21 is closed, the electric charge is stored on the main storage capacitor 23 from the battery 20 by way of the switch 21 and the resistor 23. Simultaneously the triggering capacitors 27 and 29 are charged from the battery 20 through the trigger resistor 26. The electric charge is also accumulated on the capacitors 40, 46 and 48 from the battery 20.
In thus conditions, the operation of the flash tube circuit E is initiated by the closing of switch 31 of the switching circuit D in synchronism with the camera shutter opening operation, enabling flash tubes 17 and 19. When the switch 31 is closed, the electric charge of the trigger capacitor 27 is discharged through the switch 31 and the input winding 28a of the trigger transformer 28, and the electric charge of trigger capacitor 29 is simultaneously discharged through the switch 31 and the in-put winding 30a of the trigger transformer 30. By the discharge of capacitor 26, a triggering pulse is generated from the out-put winding 28b of the trigger transformer 28. And, at the same, a gating pulse appears from the input winding 30b of the pulse transformer 30, by discharging of the capacitor 29.
The stored voltage on the main storage capacitor 23 also appears across the electrodes 17a and 17b of the first fla~h h llS7S)'78 tube 17 and across the l9a and l9b of the second flash tube 19.
The triggering pulse from the output winding 28b of the trigger transformer 28 is applied to the trigger electrodes 17c cmd l9c of the tubes 17 and 19. The firing pulse from the output winding 30b of the trigger transformer 30 is applied to the gate electrode of the first thyristor 32 and the thyristor 32 is turned on. When the thyristor 32 becomes conductive, the first flash tube 17 initiates a flash discharge between the electrodes 17a and 17b, and, at the same time the second flash tube 19 also initiates a flash between the electrodes l9a and l9b, because each trigger electrode 17c and l9c is commonly connected to the output winding 28b of the trigger transformer 28. Under normal operations heretofore, the flash continues until the main storage capacitor 23 has discharged through the tubes 17 and 19 to the point where the voltage will no longer support the flash across the tubes 17 and 19. That usually requires about several millisecond of time.
The light sensitive circuit H senses the flash light from the tubes 17 and 19, and automatically adjusts the maximum time duration of the flash produced across the tubes 17 and 19.
The maximum time duration of flash remains at that time deter-mined by the discharge of the main storage capacitor 23 through the first and the second flash tubes 17 and 19.
More specifically, when the flash light is reflected into the phototransistor 47 from the object being photographed, the resistance of the phototransistor 47 decreases rapidly following the incident flash of light. Since the decay time of the conductivity of photocell 47 is low relative to the flash interval, the photocell 47 in and of itself effect_vely inte-grates the incident light, converting that incident light intoa voltage ~57~
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signal of increasing magnitude appearing at the protecting resistor 53, thence to the zener diode 49. When the signal at zener diode 49 has reached a predetermined and fixed breakdown voltage, the zener diode 49 becomes suddenly conductive and a voltage is developed across the resistor 50 producing a sharp pulse of energy to the gate electrode of the thyristor 45.
The sharp pulse applied to the gate electrode of the thyristor 45 causes that thyristor 45 to become suddenly conductive, effectively short-circuiting the capacitor 48. This, in turn, causes the capacitor 48 to discharge, thereby applying a sharp pulse of energy to the input winding 42a of the quench trans-former 42. The transformer 42 transmits the triggering pulse from the output winding 42b thereof to the triggering electrode 38c of the quench tube 38, That triggering pulse causes the quench tube 38 to become instantaneously conductive.
When the quench tube 38 becomes conductive, electric charge of the commutation capacitor 40 also discharges through the quench tube 38 and the commutation resistor 41, and thereby the voltage is induced between both terminals of the commuta-tion resistor 41 so as to be positive polarity at the cathode electrode side of the first thyristor 32, after a time interval decided by a time constant of the capacitor 40 and the resistor 41. This induced voltage at the resistor 41 causes the first thyristor 32 to turn off. When the first thyristor becomes non-conductive, the first and the second flash tubes 17 and l9 are simultaneously and instantaneously extinguished, because the main current conducting electrode 17b and l9b of each flash tubes 17 and 19 are commonly connected to the anode electrode of the first thyristor 32.
In this case, since the quench tube 38 is the much lower , ......... _ . _ impedance, when conductive, than do the first flash tube 17 and the second flash tube 19, almost all of the stored energy in main storage capacitor 23 is discharged through the current limiting resistor 39 and the quench tube 38, causing the first flash tube 17 and the second flash tube 19 to be extinguished at such time as sufficient light has been reflected onto the photocell 47 to effect the initiation of the quenching.
Fig. 3 shows an example of bounce photographing in a room or photo-stu~io, by using the electric flash apparatus in accordance with the present invention. As is best shown in Fig~ 3, the flash housing 10 is mounted on a camera 54. The first flashing member 16 of the first casing 11 is directed toward an object to be photographed such as, for example, a man 55. The second casing 12 is set with a suitable angle with respect to the first casing 11, and the second flashing member 18 is directed toward a ceiling 56 with a desired angle with respect to a surface of the ceiling 56, in order to apply the reflected flash light to the object to be photographed. That is to say, a flash light 58 from the first flashing member 16 is directed toward the man 55, and, on the other, a flash light 59 from the second flashing member 18 i9 directed toward the surface of the ceiling 56. The flash light 59 reflects at the surface of the ceiling 56 and forms the bounce light. One reflected light 59a of the flash light 59 incidents on the man 55, and other reflected light 59b of the flash light 59 incident on a background such as, for example, a wall 57 of the room.
The one reflected flash light 59a is superimposed with the flash light 58 from the first fla3hing member 16 and, on the other hand, the reflected light 59b gets rid of the shadow in the background of the man 55.

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As dlscussed in the ~asegoing, quantity oi the fla~h light 59 is set 80 as to be greater than that oi the ilash `
light 58 produced irom the iirst flash tube 17 by connecting the current-limitting resistor 37 thereto (see Fig. 1), as is best shown in ~'ig. 4. Fig. 4 shows characteri~tics of ilash light quantity ~ on the order of Beam Candle Per ~econd (BCP~) with re~pect to Time T on the order oi Milliseco~d(l~S).
In Fig. 4, a curve 60 denote3 a ilash light characteristic oi the first light tube 17, a curve 61 designates a ilash light characteristic of the second ilash light tube 19 and a curve 62 illustrates the resultant quantities which is the 8um 0 the ~lash lights oi the iirst tube 17 and the second flash tube 19. A~ is apparent from the curve 62 in ~ig. 4, a total amount oi the flash light produced irom the flash apparat~s in accordsnce with the present invention becomes greater thsn that oi the conventional ilash apparatus which has only one ilashlng member.
Accordingly, the photographing mode shown in Flg. 3, brightness in the ob~ect to be photographed æuch as the man 55 increases and i8 made uniiorm. The ilash duration~ oi the iirst ila~h tube 17 and the second ila~h tube 19 is determined to the time interval 21 aB i8 shown ln Fig. 5. The tlme in-terval '~1 i8 presel~cted in synchronlsm with the shutter operation of the camera 54. The ilash duratlon~ oi the tube~
17 and 19 are synchronised and set at the time point Tl, and each oi the tubes 17 and 19 are simultaneously extingui~hed at the time '1`1 a8 is shown in Flg. 5. Accordingly, the un-neces~ary ilashing o~ the tube~ 17 and 19 sre avoided and, thereiore, the ~lashing periormance is enhanced, and thereby the rated capacity oi the main storage capacitor 23 is made ~i~573~7~

small, although the apparatus is equipped with the first flash tube 17 and the second flash tube 19. Furthermore, as as the total quantity of the flash light is summed by the light from first flashing member 16 and the second flashing member, the total quantity of light incident on the photo-graphic object and, as a result, the catch light is duly obtained in the photographic object. Additionally, the direct light to be directed toward the object to be photo-graphed from the first flashing member 16 includes a direct light which is directly directed to the object from the flash tube and a direct light which is directed toward the object from the flash tube by way of a reflecting member such as a reflecting mirror. Furthermore, the bounced light includes an indirect light which is directed toward the ceiling from the flash tube and which is reflected from the ceiling, and an indirect light which is generated from the flash tube and thereafter is reflected from a reflecting member positioned in the vicinity of the flash tube.
The electric flash apparatus described herein-above and illustrated by the Figures has the advantage ofbeing very certain in operation and of enabling numerous discharges of flash tubes to be effected without replacing the various elements, since the triggering circuit member C
is constructed by only one trigger transformer 28 and only one triggering capacitor 27, The electric flash apparatus described hereinabove has, moreover, advantage that the circuit construction is - simplified and smallized, since the switching circuit D is commonly and effectively used for a plurality of flash tubes of the flash tube circuit E.

`l ~ 57~

As is apparent from the hereinabove description, according to the present invention, the following advantages are obtained.
An advantage over the prior art flash apparatus is that the invention provides a new electric flash apparatus which can perform the bounce photographing by means of setting an angle between a first casing and a second casing to the desired value since the first casing and the second casing are rotatably connected to each.
Another advantage of the invention is that both of a first flashing member and a second flashing member can also be used as a direct-light source by directing the both of - 14a -~7~78 them toward the object to be photographed and, as a result, the qu;~ntity of an incident light to the object increases to that extent.
A further advantage of the invention is that an electric ~lash apparatus is convenient to take a photograph, particular-ly to taking a picture by employing a bounce light because a ~lash housing is rotably constructed by a first casing and a second casing, each o~ the casing has a ~lashing member.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
While a pre~ered embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that modifications can be made without departing from the principle and spirit o~ the invention, the scope oY
which is de~ined in the appended claims. Accordingly, the foregoing embodiment is to be considered illustrative, rather than restricting of the invention and those modiYications which come within the meaning and range o~ equivalency oY
the claims are to be included herein.

Claims (12)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. An electric flash apparatus having a circuit for charging a main capacitor, a flash tube circuit actuated by the operation of a trigger circuit when an electric charge is stored on said main capacitor, a plurality of flashing members, each of which includes at least one flash tube, and a flash control circuit arrangement for receiving light generated from said flashing members and reflected from an object to be photographed and converting said light to an electric energy and for controlling automatically flash-light quantity when said electric energy attains a predetermined value, said flashing members comprising a first flashing member adaptable to generate direct light with respect to said object to be photographed, a second flashing member adaptable to generate indirect light with respect to said object, means for making the illumination direction of said second flashing member adjustable, and means for adjust-ing flash light quantity such that the flash light quantity of said first flashing member is less than that of said second flashing member when said first and second flashing members activate.

2. An electric flash apparatus as claimed in claim 1, further comprising a flash stopping circuit for extinguishing simultaneously said flash tubes of the flash tube circuit, a trigger signal generating circuit for actuating said flash stopping circuit and for supplying a triggering signal to the flash stopping circuit, and a light-sensitive circuit for sensing a flash light from said flashing members and for actuating the trigger signal generating circuit in response to said light flash

3. An electric flash apparatus as claimed in claim 2 wherein said trigger circuit includes a first trigger capacitor, and an input winding of a trigger transformer is connected in series to said trigger capacitor and an output winding of the trigger transformer is connected to said flashing members.

4. An electric flash apparatus as claimed in claim 3 and including a switching circuit for simultaneously actuating said first and second flashing members, said switching circuit comprising a second trigger capacitor, a pulse transformer having an input winding connected to the second trigger capacitor, a synchronous switch connected in series to said input winding of said pulse transformer together with said input winding of said trigger transformer of the trigger signal generating circuit, and a first switching element which is made turn on by a signal from an output winding of said pulse transformer.

5. An electric flash apparatus as claimed in claim 4 including a flash tube circuit comprising a first flash tube whose main current conducting electrodes are connected to the main storage capacitor by way of the switching element of said switching circuit and whose triggering electrode is connected to an output winding of the trigger circuit, a current limiting element for limiting a flash current from the main storage capacitor between the main storage capacitor and the other main conducting electrode of said first flash tube, and a second flash tube whose main current conducting electrode are connected in parallel relationship to a series circuit of the first flash tube and the current limiting resistor element and whose triggering electrode is connected to the output winding of the trigger transformer together with the trigger electrode of the first flash tube.

6. An electric flash apparatus as claimed in claim 5 wherein said flash stopping circuit comprises a second switching element which is connected in parallel to said flash tubes and said switching element of the switching circuit, and a commutation circuit for turning off said switching element of said switching circuit.

7. An electric flash apparatus as claimed in claim 6 wherein the trigger signal generating circuit includes a quench transformer whose one output winding is connected to a triggering electrode of a quench tube of the flash stop-ping circuit, a third switching element connected in series relationship to an input winding of said quench trigger transformer.

8. An electric flash apparatus as claimed in claim 7 wherein said light sensitive circuit includes a light sen-sitive element which is made conductive by an incidenting light thereon and which applies a signal to the switching element of said trigger signal generating circuit.

9. An electric flash apparatus as claimed in claim 8 wherein said third switching element is a first thyristor.

10. An electric flash apparatus as claimed in claim 9 wherein said current-limiting element is a resistor which is connected in series to the first flash tube.

11. An electric flash apparatus as claimed in claim 10 wherein said commutation circuit comprises a commutation capacitor interposed between a main electrode of the quench tube and an anode electrode of a second thyristor, and a commutation resistor connected between the anode electrode and a cathode.

12. An electric flash apparatus as claimed in claim 11 wherein said light sensitive element is a photo-transistor connected to a gate electrode of the first thyristor by way of a gate resistor.