JP2002169252A - Film unit with lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the quantity of stroboscopic light emission for use in performing a stroboscopic photographing. SOLUTION: A blocking oscillation circuit is constituted of an oscillation transistor 25 and an oscillation transformer 26 and the like to charges a main capacitor 28. When a charging switch 22 and a light emission selecting switch 23 are turned ON, the main capacitor 28 is charged to a voltage exceeding the charging voltage of a specified level. As a result, this stroboscope device can perform a stroboscopic light emission having a normal emitted light quantity. Moreover, when the charging switch 22, the light emission selecting switch 23 and light emitting quantity reducing switches 24a, 24b are turned ON, an oscillation stopping circuit 32 and a discharge circuit 33 go into action and the capacitor 28 is charged to the charging voltage of an adjusted level lower than the charging voltage of the specified level. Thus, the device can perform a stroboscopic light emission having an emitted light quantity smaller than the normal emitted light quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film unit with a lens, and more particularly, to a film unit with a lens for performing flash photography by selectively switching the amount of flash light emission according to the photographing distance.

[0002]

2. Description of the Related Art As a simple camera, a film unit with a lens on which an unexposed photographic film is loaded in advance at the time of manufacture is manufactured and sold by the present applicant. There are various types of film units with lenses depending on the application. Among them, those having a built-in strobe device capable of taking an image of a subject with an insufficient exposure amount in a dark place or in a room have become widespread.

[0003]

However, in the film unit with a lens as described above, a high-precision exposure control device and an auto strobe cannot be used in view of manufacturing costs. There is a drawback that overexposure is likely to occur in a main subject in distance shooting and insufficient light amount in long distance shooting. This drawback cannot be dealt with only by switching the aperture.

The present invention has been made to solve the above-mentioned problem, and has a simple configuration so that the strobe light emission amount can be switched in two steps, and the strobe light emission amount can be switched in two steps according to the distance of the photographing distance. An object of the present invention is to provide a film unit with a lens having a built-in circuit.

[0005]

In order to achieve the above object, a film unit with a lens according to the present invention is provided with a lens which enables strobe photography by discharging electric charges stored in a main condenser through a strobe discharge tube. In the film unit, an operation member switched between a first set position and a second set position, and when the operation member is switched to the first set position, the main capacitor is charged beyond a prescribed level and operated. A charge control circuit for detecting that the main capacitor has been charged to an adjustment level lower than a specified level and stopping charging when the member is switched to the second set position.

[0006] Further, in conjunction with switching the operation member to the second set position, there is provided discharging means for lowering the charging voltage of the main capacitor charged beyond the adjustment level to the adjustment level. Is an index indicating long-distance shooting, and an index indicating short-distance shooting is provided at the second set position.

[0007]

FIG. 1 is an external view showing a film unit with a lens according to the present invention. The lens-equipped film unit 10 includes a unit main body 11 in which various photographing mechanisms and a strobe device are incorporated, and in which a film cartridge is previously loaded, and a label 12 that partially covers the unit main body 11.

A shutter button 13 and a film counter window 14 are provided on the upper surface of the unit main body 11, and an object-side finder window 15, a photographing lens 16, a flash operating lever 17, and a flash emitting section 18 are provided on the front. . On the back, besides the film winding knob 19,
An eyepiece side finder window (not shown) is provided. The label 12 has an adhesive applied to the back surface thereof and the unit body 1
The film counter window 14, the object-side finder window 15, the photographing lens 16, the eyepiece-side finder window, and the like are exposed to the outside through openings provided in each part.

The strobe operation lever 17 is provided with an "O"
FF "position 17a," ON1 "position 17b," ON2 "
It is possible to selectively switch to any one of the positions 17c. When the strobe operation lever 17 is
When the position is switched to the position "F" 17a, the main capacitor of the strobe circuit, which will be described later, is not charged, and the strobe light is not emitted during photographing regardless of the charging voltage of the main capacitor. Also, set the flash operation lever 17 to "ON".
1) When the position is switched to the position 17b, a normal strobe mode is set in which the main capacitor is charged to a charging voltage equal to or higher than a specified level, and strobe light emission of a normal light emission amount is performed at the time of photographing. Further, when the position is switched to the "ON2" position 17c, the main capacitor is charged to a charging voltage of an adjustment level lower than the charging voltage of the specified level, and a subject located at a short distance is not overexposed so as to prevent overexposure during shooting. This is a short-range strobe mode in which strobe light emission with a small light emission amount is performed.

In FIG. 2, a strobe circuit 20 includes a battery 21, a charge switch 22, a light emission selection switch 23, light emission amount reduction switches 24a and 24b, an oscillation transistor 2
5, oscillation transformer 26, strobe discharge tube 27, main capacitor 28, trigger capacitor 29, trigger coil 3
0, a synchro switch 31, an oscillation stop circuit 32, a discharge circuit 33, etc., and a blocking oscillation circuit including an oscillation transistor 25, an oscillation transformer 26, etc.
The low voltage of the battery is converted to a high voltage and the main capacitor 28
Charge.

Charge switch 22, light emission selection switch 2
3. The light emission amount reduction switches 24a and 24b are turned on / off in conjunction with the above-described strobe operation lever 17, respectively. When the flash operation lever 17 is in the "ON1" position 17b, only the charge switch 22 and the light emission selection switch 23 are ON.
In the “ON2” position 17c, the switches 22 and 2
3, 24a and 24b are turned ON. At the "OFF" position 17a, the switches 22, 23, 24a and 24b are turned off.

The oscillation transformer 26 includes a primary coil 35, a secondary coil 36, and a tertiary coil 3 which are inductively coupled to each other.
7. In the oscillation transformer 26, each terminal of the primary coil 35 has a first terminal 39a and a second terminal 39.
b, one terminal of the secondary coil 36 is a third terminal 39c.
Further, the other terminal is a fourth terminal 39d which is a common terminal with one terminal of the tertiary coil 37, and the other terminal of the tertiary coil 37 is a fifth terminal e. The secondary coil 36 has
An intermediate output terminal 39f is provided.

The primary coil 35 has a first terminal 39a connected to the collector terminal of the oscillation transistor 25 and a second terminal 39b connected to the positive electrode of the battery 21. The primary current flowing through the primary coil 35 is supplied from the battery 21 and controlled by the oscillation transistor 25. Also,
The tertiary coil 37 has a fourth terminal 39d, which is a shared terminal with the secondary coil 36, connected to the base terminal of the oscillation transistor 25 via the charging switch 22 and the resistor 40, and a fifth terminal 39e connected to the battery via the resistor 41. 21 plus electrodes. The emitter terminal of the oscillating transistor 25 is connected to the negative electrode of the battery 21 and grounded. The positive terminal of the main capacitor 28 is connected to this emitter terminal. The third terminal 39c of the secondary coil 36 is connected to the minus side of the main capacitor 28 via the rectifying diode 42.

The trigger coil 30 is composed of a primary coil 43 and a secondary coil 44 which are inductively coupled. One end of each of the primary coil 43 and the secondary coil 44 is a common terminal. The other end of the primary coil 43 is connected to one end of the trigger capacitor 29, and the other end of the secondary coil 44 is connected to a trigger electrode 45 provided near the strobe discharge tube 27. The common terminal of each of the coils 43 and 44 is connected to the fourth terminal 39d of the secondary coil 36 via the sync switch 31. Both terminals of the strobe discharge tube 27 are connected to both terminals of the main capacitor 28.

The strobe circuit 20 connected as described above
Are the resistance 41 and the tertiary coil 3 from the positive electrode of the battery 21.
7, charging switch 22, resistor 40, oscillation transistor 2
The circuit sequentially connected to the negative electrode of the battery 21 through the base and the emitter of No. 5 is a bias circuit for flowing a bias current for operating the oscillation transistor 25.

The charge switch 22, the resistor 40, and the oscillation transistor 25 are connected from the fourth terminal 39d of the secondary coil 36 to
A circuit sequentially connected between the base and the emitter, the main capacitor 28, the rectifying diode 42, and the third terminal 39c of the secondary coil 36 charges the main capacitor 28 and causes the oscillation transistor 25 to oscillate. It is a main secondary circuit that allows current to flow. Further, the light emitting selection switch 2 is connected to the fourth terminal 39d of the secondary coil 36.
3, a circuit sequentially connected to the trigger capacitor 29, the resistor 46, the rectifying diode 42, and the third terminal 39c of the secondary coil 36 is a sub-secondary circuit for charging the trigger capacitor 29.

The circuit sequentially connected from one end of the trigger capacitor 29 to the light emission selection switch 23, the synchro switch 31, the primary coil 43 of the trigger transformer 30, and the other end of the trigger capacitor 29 is a synchro switch 3
This is a trigger discharge circuit that causes the discharge current from the trigger capacitor 29 to flow to the primary coil 43 when 1 is turned on.

When the strobe operation lever 17 is in the "ON1" position 17b where the strobe mode is normally in the strobe mode, that is, when the charge switch 22 and the light emission selection switch 23 are turned on and the light emission amount reduction switches 24a and 24b are turned off, the bias circuit and the main secondary side are turned off. The circuit and the sub-secondary circuit are closed. When the bias circuit is closed, the oscillation transistor 25 receives the power supply from the battery 21 to the base terminal, starts the base current (bias current) and starts operating, and supplies the primary coil 35 with the primary current (collector current). Shed. Then, the oscillation transistor 25 oscillates by increasing the collector current as the base current increases, with the secondary current flowing through the main secondary circuit flowing back as the feedback action of the oscillation transformer 26.

The secondary coil 36 generates a high voltage electromotive force according to the winding ratio between the primary coil 35 and the secondary coil 36 during the operation of the blocking oscillation circuit. This electromotive force is
The secondary current flows from the third terminal 39c toward the fourth terminal 39d. As a result, as shown in FIG. 3, the main capacitor 28 is charged at the specified level of the charging voltage Va.
, And the trigger capacitor 29 is also charged in proportion to the rise in the charging voltage of the main capacitor 28. The winding ratio between the primary coil 35 and the secondary coil 36 is determined by the fact that the electromotive force generated in the secondary coil 36 is
Is substantially the same as the full charge voltage Vf.

In FIG. 2, a light emitting diode 50 is provided to notify a photographer that charging has been completed. The light emitting diode 50 has an anode connected to the fourth terminal 39 d of the oscillation transformer 26 and a cathode connected to the fifth terminal 39 e via the resistor 51. The light emitting diode 50 is connected to the fourth terminal 39 according to a change in the charging voltage of the main capacitor 28 during the operation of the blocking oscillation circuit.
The main capacitor 28 is illuminated by utilizing the change in the voltage between the terminal d and the fifth terminal 39e.
Is turned on when the charging voltage is charged to a predetermined display charging voltage Vb.

When the main capacitor 28 is charged to a specified level or more of the charging voltage Va and the sync switch 31 is turned on to close the trigger discharge circuit while the charge switch 22 and the light emission selection switch 23 are on, the trigger capacitor 29 The discharge current is the primary coil 4 of the trigger coil 30
Flow to 3. When a discharge current flows through the primary coil 43, a trigger voltage is generated in the secondary coil 44, and this trigger voltage is applied to the strobe discharge tube 27 via the trigger electrode 45. Then, the insulation in the strobe discharge tube 27 is broken, the electric charge of the main capacitor 28 is discharged, and the strobe light is emitted from the strobe discharge tube 27. Thus, in the normal strobe mode, strobe light emission of a normal light emission amount is performed.

Next, when the strobe operation lever 17 is in the "ON2" position 17c where the short-range strobe mode is set, that is, when the charge switch 22, the light emission selection switch 23 and the light emission amount reduction switches 24a and 24b are turned on, the bias circuit and the main circuit The secondary circuit and the secondary circuit are closed, and the oscillation stop circuit 32 and the discharge circuit 33 are closed. The bias circuit, the main secondary circuit, and the sub secondary circuit operate in the same manner as described above, and start charging the main capacitor 28 and the trigger capacitor 29.

The oscillation stop circuit 32 includes a main capacitor 2
8 is provided to stop the charging by the blocking oscillation circuit when the battery 8 is charged to the charging voltage Vc of the adjustment level lower than the charging voltage Va of the specified level (see FIG. 4). ,
Stop capacitor 55, diode 56, resistors 57 and 5
8, 59, etc.

The diode 56 has a cathode connected to the intermediate output terminal 39f via the light emission reduction switch 24a, and an anode connected to the Zener diode 53 via the resistor 57.
Connected to the anode. The cathode of the Zener diode 53 is connected to a fourth terminal 39 d via a stopping capacitor 55.
When the main capacitor 28 reaches the charging voltage Vc at the adjustment level, the stopping capacitor 55 is charged by a Zener current (reverse current) flowing through the Zener diode 53.

The stop transistor 54 has a base terminal connected to the cathode of the Zener diode 53 via a resistor 58,
The emitter terminal is connected to the base terminal of the oscillation transistor 25 via the charging switch 22 and the resistor 40, respectively.
The collector terminal is grounded. The stop transistor 54 is turned ON (conduction state between the emitter and the collector) by the base voltage obtained from the charged charging voltage of the stop capacitor 55, and the charge of the stop capacitor 55 is changed to the resistors 58 and 59, It is turned off when the battery is discharged at 54 and its charged voltage drops to a predetermined voltage. The stop transistor 54 is turned on for a time T corresponding to a time constant determined by the stop capacitor 55 and the capacitances and resistances of the resistors 58 and 59.

When the stop transistor 54 is turned on,
The base and emitter terminals of the oscillation transistor 25 are short-circuited, the oscillation transistor 25 is turned off, the blocking oscillation circuit is stopped, and the charging of the main capacitor 28 and the trigger capacitor 29 is stopped. At this time,
Since the charging voltage of the main capacitor 28 slightly decreases due to internal discharge or the like, the charging voltage of the stopping capacitor 55 drops to a predetermined voltage, and when the stopping transistor 54 is turned off, the oscillation transistor 25 is turned on again.
N, the blocking oscillation circuit is activated, and the main capacitor 28 and the trigger capacitor 29 are charged. When the main capacitor 28 reaches the charging voltage Vc at the adjustment level, charging is stopped again. In this manner, the blocking oscillation circuit is intermittently operated to maintain the charging voltage of the main capacitor 28 at the charging voltage Vc at the substantially adjusted level (see FIG. 4).

The light emitting diode 50 is turned on when the main capacitor 28 is charged to the predetermined display charging voltage Vb during the operation of the blocking oscillation circuit. In order to maintain the voltage Vc, the light is repeatedly turned off and turned on and off in response to the intermittent operation of the blocking oscillation circuit.

The discharge circuit 33 includes a light emission amount reduction switch 24.
b, a Zener diode 61, and a resistor 62. As shown in FIG. 5, when the main capacitor 28 is charged to a charging voltage exceeding the charging voltage Vc of the adjustment level, the discharging circuit 33 sets the strobe operating lever 17 to the "ON1" position 17b, for example, and sets the normal strobe mode. When the flash operation lever 17 is switched to the "ON2" position 17c of the short-distance flash mode at T1 in the drawing to perform short-distance shooting after the flash charging is performed, the charging voltage of the main capacitor 28 is adjusted to the adjustment level. Is provided to discharge the electric charge until the charging voltage Vc becomes equal to.

In FIG. 2, the cathode of the Zener diode 61 is connected to the minus side of the main capacitor 28 via a light emission amount reducing switch 24b, and the anode is connected to the plus side of the main capacitor 28 via a resistor 62. When the charging voltage of the main capacitor 28 is higher than the charging voltage Vc of the adjustment level, a Zener current flows through the Zener diode 61 and the charge of the main capacitor 28 is
2 discharges. When the charge voltage of the main capacitor 28 falls to the charge voltage Vc of the adjustment level, no Zener current flows through the Zener diode 61, and no further discharge is performed.

The main capacitor 28 is charged to the charging voltage Vc at the adjustment level, and the charge switch 22, the light emission selection switch 23, and the light emission amount reduction switches 24a and 24b are turned on.
When the synchro switch 31 is turned on in this state, the trigger discharge circuit is closed and the trigger voltage is applied to the strobe discharge tube 27 via the trigger electrode 45 as described above. Then, the insulation in the strobe discharge tube 27 is broken, the electric charge of the main capacitor 28 is discharged, and the strobe light is emitted from the strobe discharge tube 27. Since the main capacitor 28 is charged to the charging voltage Vc of the adjustment level lower than the charging voltage Va of the specified level, in the short-distance strobe mode, strobe light emission of a light emission amount smaller than a normal light emission amount is performed.

At the beginning of the flow of the Zener current, the Zener current is charged in the stopping capacitor 55, so that the stopping transistor 54 does not immediately turn ON, and the main capacitor 28 reaches the predetermined charging voltage Vc. Since it is turned ON slightly later than the time when the charging is performed, the charging voltage of the main capacitor 28 at the time of stopping charging becomes slightly higher than the predetermined charging voltage Vc by the delay (see FIG. 4).

The diode 56 is connected to the intermediate output terminal 3
The diode 56 serves as a rectifier for taking out a current in the direction in which a Zener current flows from the 9f to the Zener diode 53, and serves as a temperature compensation circuit for the Zener diode 53. The diodes 56 having different signs (positive and negative) of the temperature coefficient are different from each other. And the Zener diode 53 are used in combination to make the overall temperature coefficient substantially "0" and prevent the occurrence of variation in charging voltage when the main capacitor 28 is charged to the charging voltage Vc at the adjustment level.

When the slide operation lever 17 is turned to the "OFF" position 17a, that is, when the charge switch 22, the light emission selection switch 23 and the light emission amount reduction switches 24a and 24b are turned off, the bias circuit, the main secondary circuit, and the sub secondary circuit are set. Is opened. When the bias circuit and the main secondary circuit are opened, the bias current and the secondary current as the base current do not flow through the oscillation transistor 25, so that the oscillation transistor 25 is turned off, the blocking oscillation circuit is stopped, and the main capacitor 28 is turned off. And the trigger capacitor 29
Is stopped.

Even if the synchro switch 31 is turned on while the switches 22, 23, 24a and 24b are off, the trigger discharge circuit is opened by the light emission selection switch 23. Irrespective of this, the trigger capacitor 29 does not discharge and no strobe light emission is performed.

A protection diode 65 is connected between one end of the charging switch 22 connected to the base terminal of the oscillation transistor 25 via the resistor 40 and the emitter terminal of the oscillation transistor 25, that is, the ground line. The protection diode 65 is connected in such a manner that the emitter terminal side of the oscillation transistor 25 becomes an anode, and the synchro switch 31 is turned on, and the trigger capacitor 29 is turned on.
Is discharged, the voltage applied between the base and the emitter of the oscillation transistor 25 is reduced.
5 is prevented from being deteriorated or destroyed.

Next, the operation of the above configuration will be described.
The photographer turns the film winding knob 19 of the film unit with lens 10 to wind the photographic film to prepare for photographing. At this time, the shutter charge is simultaneously performed by rotating the film winding knob. When performing flash photography, the flash operation lever 17 is moved to the “ON1” position 17 according to the distance to the subject.
b, or switch to the "ON2" position 17c by sliding.

When the flash operation lever 17 is set to the "ON1" position 17b where the flash mode is normally set, the charging switch 22 and the light emission selection switch 23 are turned on, respectively, and the bias circuit, the main secondary circuit, and the sub secondary circuit are turned on. Is closed. When the bias circuit is closed, the oscillation transistor 25 receives power supply from the battery 21 to the base terminal,
The base current (bias current) flows and the operation starts, and a primary current (collector current) flows through the primary coil 35. Then, the oscillating transistor 25 oscillates by the feedback action of the oscillating transformer 26 to increase the primary current flowing through the primary coil 35.

When the primary current increases, the secondary coil 36
, A high-voltage electromotive force corresponding to the winding ratio between the primary coil 35 and the secondary coil 36 is generated in the direction in which the secondary current flows from the third terminal 39c toward the fourth terminal 39d. The secondary current due to the electromotive force flows through the main secondary circuit and the sub secondary circuit, and charges the main capacitor 28 and the trigger capacitor 29.

When the main capacitor 28 has the display charging voltage Vb
When charging is completed, the light emitting diode 50 is turned on. The light of the light emitting diode 50 is guided to a display member (not shown) provided near the eyepiece side finder window or on the upper surface of the film unit with the lens through the light guide. The photographer can turn on the main condenser 28 by turning on the display member.
It can be confirmed that is charged in the normal strobe mode.

When the shutter button 13 is pressed, the shutter blades are operated by the shutter mechanism. As soon as the shutter blades are fully opened, the synchro switch 31 is turned on.
Becomes Since the light emission selection switch 23 is ON, when the synchro switch 31 is turned ON, the trigger capacitor 29 is discharged, and the trigger voltage from the trigger coil 30 generated by this discharge is transmitted via the trigger electrode 45 to the strobe discharge tube 27. Applied to. As a result, the electric charge of the main capacitor 28 charged above the specified level of the charging voltage Va is discharged in the strobe discharge tube 27, and strobe light emission with a normal light emission amount is performed.

When the flash operation lever 17 is set to the "ON2" position 17c where the short-range flash mode is set,
The charge switch 22, the light emission selection switch 23, and the light emission amount reduction switches 24a and 24b are turned ON, the bias circuit, the main secondary circuit, and the sub secondary circuit are closed, and the oscillation stop circuit 32 and the discharge circuit 33 are closed. Can be The bias circuit, the main secondary circuit, and the sub secondary circuit operate in the same manner as described above, and start charging the main capacitor 28 and the trigger capacitor 29.

When the main capacitor 28 has the display charging voltage Vb
When charging is completed, the light emitting diode 50 is turned on. When the main capacitor 28 reaches the charging voltage Vc at the adjustment level, the oscillation stop circuit 32 stops charging by the blocking oscillation circuit, and the light emitting diode 50 is turned off. A time T corresponding to a time constant determined by the capacitance of the stopping capacitor 55, the capacitance of the resistors 58 and 59, and the resistance value.
Elapses, the stop transistor 54 is turned off and the oscillation transistor 25 is turned on.

During the time T during which the oscillation transistor 25 is OFF, the charging voltage of the main capacitor 28 slightly decreases due to internal discharge or the like. Charging is performed again. At this time, the light emitting diode 5
0 lights up again.

When the charging voltage of the main capacitor 28 reaches the charging voltage Vc of the adjustment level again, the oscillation stop circuit 32
As a result, charging by the blocking oscillation circuit is stopped. In this way, by intermittently operating the blocking oscillation circuit, the charging voltage of the main capacitor 28 is maintained at the charging voltage Vc of the substantially adjusted level, and the light emitting diode 50 is turned on and off in response to the intermittent operation of the blocking oscillation circuit. Flashes repeatedly after turning off. The photographer can confirm that the main condenser 28 is charged in the short-range strobe mode by the blinking of the above-mentioned display member to which the light of the light emitting diode 50 is guided.

Then, the flash operation lever 17 is turned on.
"1" position 17b and charge the flash
2 "When the main condenser 28 is set at the position 17c,
Is charged to a charge voltage higher than the charge voltage Vc at the adjustment level, the discharge circuit 33 discharges the charge until the charge voltage of the main capacitor 28 becomes the charge voltage Vc at the adjustment level. Then, the main capacitor 28
The blocking oscillation circuit operates intermittently so that the charging voltage is maintained at the charging voltage Vc substantially at the adjustment level.

When the shutter button 13 is pressed, the shutter blades are operated by the shutter mechanism, and the synchro switch 31 is turned on at the moment when the shutter blades are fully opened. Since the light emission selection switch 23 is ON, when the synchro switch 31 is turned ON, the trigger capacitor 29 is discharged, and the trigger voltage from the trigger coil 30 generated by this discharge is transmitted via the trigger electrode 45 to the strobe discharge tube 27. Applied to. As a result, the electric charge of the main capacitor 28 charged to the charging voltage Vc at the adjustment level is discharged in the strobe discharge tube 27, and strobe light emission is performed with a light emission amount smaller than usual.

[0047]

As described above, according to the strobe circuit of the present invention, the operating member switched between the first set position and the second set position, and the operating member is switched to the first set position. When the operation member is switched to the second set position, it is detected that the main capacitor has been charged to an adjustment level lower than the specified level, and charging is stopped when the operation member is switched to the second set position. Since the control circuit is provided, it is possible to perform strobe shooting by switching the strobe light emission amount between two levels according to the shooting distance.

[Brief description of the drawings]

FIG. 1 is a perspective view of a film unit with a lens according to the present invention.

FIG. 2 is a circuit diagram of a flash circuit of the film unit with a lens according to the present invention.

FIG. 3 is an explanatory diagram of a charged state of a main capacitor in a normal strobe mode.

FIG. 4 is an explanatory diagram of a charged state of a main capacitor in a short-range strobe mode.

FIG. 5 is an explanatory diagram of a charged state of a main capacitor when switching from a normal strobe mode to a short-range strobe mode.

[Explanation of symbols]

 Reference Signs List 10 Film unit with lens 18 Strobe light emitting unit 20 Strobe circuit 21 Battery 22 Charge switch 23 Light emission selection switch 24 Light emission amount reduction switch 25 Oscillation transistor 26 Oscillation transformer 27 Strobe discharge tube 28 Main capacitor 31 Synchro switch 32 Oscillation stop circuit 33 Discharge circuit 50 Light emitting diode 54 Stop transistor 55 Stop capacitor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 15/03 G03B 15/03 H K 15/05 15/05 17/02 17/02 17/04 17 / 04

Claims (3)

[Claims] In a film unit with a lens capable of flash photography by discharging electric charges stored in a main condenser through a flash discharge tube, a switching operation is performed between a first set position and a second set position. An operating member, when the operating member is switched to the first set position, the main capacitor is charged beyond a prescribed level,
A charge control circuit for detecting that the main capacitor has been charged to an adjustment level lower than a specified level and stopping charging when the operation member is switched to the second set position. unit. 2. The apparatus according to claim 1, further comprising: discharging means for lowering the charging voltage of the main capacitor charged above the adjustment level to the adjustment level in conjunction with switching the operation member to the second set position. The film unit with a lens according to claim 1. 3. A lens according to claim 1, wherein an index indicating a long-distance shooting is provided at the first set position, and an index indicating a short-distance shooting is provided at the second set position. Film unit.