JP2636296B2 - Strobe device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe device, and more particularly, to charging of a strobe at the time of continuous shooting in strobe flash photography.

2. Description of the Related Art Conventionally, a continuous shooting mode in which a strobe device is built-in and exposure and automatic winding of a film are continuously repeated while a release operation member is kept pressed, and a single operation of the release operation member 2. Description of the Related Art Cameras capable of selectively performing photographing in a normal photographing mode in which exposure and automatic winding of a film are performed only once by pressing the button are well known. Since this camera has a built-in flash, it is possible to perform flash emission shooting in single frame shooting in the normal shooting mode and continuous shooting in the continuous shooting mode, and the aperture opening diameter at the time of shooting is controlled by flashmatic means. It has become.

This flashmatic means is constituted by a well-known flashmatic mechanism, and determines the aperture opening diameter based on the guide number of the built-in flash device and the distance to the subject.

By the way, the guide number of the strobe device is determined based on when the main capacitor in the strobe light emitting circuit, that is, the light emitting capacitor for making the flash discharge tube emit light is fully charged. Therefore, once flash photography is performed, it is necessary to fully charge the flash capacitor before the next flash photography.

[Problems to be Solved by the Invention] As described above, in the conventional camera with a built-in strobe, after the strobe light emission photographing is performed once, it is necessary to wait until the light emitting capacitor of the strobe device is fully charged, and then the charging voltage becomes full. Detecting that the battery has been charged, the next flash photography is performed. Therefore, the detection voltage level of the completion of the charge was only one level when the battery was fully charged. For this reason, there is a drawback that the charging time becomes longer, and when the flash emission shooting is performed in the continuous shooting mode, the continuous shooting interval becomes longer and the shooting chance is missed.

On the other hand, it is known that the strobe light is sufficiently tuned when the charging of the light-emitting capacitor reaches a voltage at which light can be emitted even if it does not reach full charge. Therefore, if the release switch is closed while the strobe is being charged using this, if the charging voltage of the strobe's light-emitting capacitor has reached the voltage at which light can be emitted, charging is temporarily interrupted to perform the exposure operation. A camera having a release priority function for starting the camera has already been proposed.

However, in this type of camera, the flash aperture mechanism is used to calculate the aperture aperture based on the guide number when the flash capacitor is fully charged during flash shooting, and the flashmatic mechanism operates, so the flash firing voltage Since the guide number has an error in the light-emission photographing at the time when the exposure time has reached, there is a problem that the exposure becomes under.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a strobe device capable of solving the above-mentioned drawback that the charging interval is lengthened and obtaining a proper exposure even during strobe photographing by flashmatic control.

[Means and Actions for Solving the Problems] As shown in the conceptual diagram of FIG. 1, the present invention provides a continuous shooting mode in which exposure and automatic film winding are repeatedly performed, and automatic exposure and film automatic winding. In a strobe device incorporated in a camera capable of performing a photographing operation in a normal photographing mode performed once each time, a boosting means 102 for boosting a voltage of a power supply 101, a capacitor 103 charged with a voltage boosted by the boosting means, A flash discharge tube 104 that emits light by discharging the charge of the capacitor; a charge detecting device that detects the charge voltage of the capacitor at least at two levels of a light emission minimum voltage of the flash discharge tube and a voltage higher than the same voltage. In the normal shooting mode, the capacitor is fully charged by the boosting means in the normal shooting mode, and in the continuous shooting mode, A boost control means for receiving a light emission minimum voltage level excess signal and stopping the boosting of the boosting means when the detecting means detects that the charging voltage has reached the light emission minimum voltage level. The charging of the light emitting capacitor in the flash light emission photographing in the mode is stopped when the lowest voltage at which light emission is possible is achieved, thereby shortening the continuous shooting interval.

[Embodiment] FIG. 2 is a block diagram showing a configuration of a main part of a camera having a flash device according to an embodiment of the present invention. CPU that detects that the release switch SW has been turned on (this may be a general controller)
Reference numeral 1 denotes a strobe charge state detection circuit 2 serving as a charge state detection unit, which detects a charge voltage level of a main capacitor of the strobe device. In this case, it is a condition that the detected charging level has necessarily reached the minimum level at which light emission is possible. Upon detecting this charge level, the CPU 1 immediately stops charging by the flash control circuit 3. And
The CPU 1 calculates a guide number at the time of flash emission based on a detection signal from the flash charging state detection circuit 2, and obtains distance information from the subject distance detection means 5 and film sensitivity information from the film sensitivity detection means 6. After determining the proper aperture value, the aperture control means 4 sets the aperture diameter to the above-mentioned aperture value. Thereafter, the flash control circuit 3 operates based on the flash start signal from the CPU 1 to perform flash flash photography.

When the release is turned on, the CPU 1 determines whether or not continuous shooting is to be performed. If continuous shooting is to be performed, the detection level of the strobe charging voltage is set to the lowest level at which light emission is possible. Accordingly, since the charging interval during continuous shooting is shortened, the shooting interval for continuous shooting is also shortened, and the conventional disadvantage can be solved.

Next, a case will be described where the strobe device of the present invention basically configured as described above is applied to a fully automatic camera employing a lens shutter.

This lens shutter camera has a basic system as shown in FIG. That is, the CPU 11 is formed of a one-chip microcomputer that controls the entire camera, and receives a basic clock from the oscillation circuit 12 and starts operation by reset of the reset circuit 13. The reset circuit 13 operates when a battery is inserted and when a power switch (not shown) is turned on and off.

E ² -PROM14 camera state (number of frames, winding secondary) and, adjustment data (shutter control, the lens drive) is a nonvolatile memory that stores. Therefore, even if the battery is removed, the camera can return to the previous state. The reset operation of the reset circuit 13 is prohibited while data is being written to the E ² -PROM 14. When the E ² -PROM 14 is set to the reading mode, the DX code is first input to the E ² -PROM 14 from the DX terminal 15 and then to the CPU 11 through the serial line. Thereafter, the data in the E ² -PROM 14 is input to the CPU 11.

The AFIC 16 is a phase difference type AF (auto focus) sensor, and its distance data is sent to the CPU 11. The CPU 11 turns on the auxiliary light lamp 17 in accordance with the operation of the AFIC 16 when the photometric value is equal to or less than a certain value (dark). The EXT terminal 18 is a connection terminal for connecting to an external device, to which an option, an automatic adjuster, and the like are connected. The E ² -PROM 14, the AFIC 16, and the EXT terminal 18 are connected to the same serial line in order to effectively use the port of the CPU 11, and exchange data with the CPU 11 by serial communication.

SW19 is a camera operation switch.
A mode change switch and the like are included. The LED 20 is a light-emitting diode in the finder, and includes a light-emitting diode for strobe light emission notice, focus indication, and the like. The LCD 21 is a liquid crystal display panel for displaying the number of frames, a camera mode, and the like.
The IFIC 22 is an interface IC having a decoding function for performing photometry by the photometry unit 23 and selecting a motor in the camera according to an instruction from the CPU 11.

M _S 24, M _W 25, M _Z 26 are shutter motor, winding /
A rewind motor and a zoom motor are driven by a decode signal of the IFIC 22 via a motor driver IC 27. The M _S 24 performs lens driving during forward rotation and performs shutter driving during reverse rotation. When the lens is driven, the reset position of the lens is confirmed by the ON (closed) state of the switch 28, and the control position is confirmed by the number of pulses of the photointerrupter 29. At the time of shutter driving, reset position is confirmed by the ON state of the switch 30, the opening control is performed by adjusting the pulse width of M _S 24. The adjustment value is stored in the E ² -PROM14. M _W 25 is wound up film in the forward direction, performs the film rewinding in reverse. One frame advance control of film is photo interrupter
This is performed by counting the number of 31 pulses. The photo interrupters 29 and 31 are turned on only when M _S 24 and M _W 25 are selected, respectively, and the photo interrupter output is input to the CPU 11 via the IFIC 22. Zoom position of M _Z 26 may be detected by a zoom encoder 32.

DATEM 33 is a date module for imprinting data such as date and time on a film, and STRB 34 is a strobe device according to the present invention.

The charging state detecting means for detecting the level of the charging voltage of the strobe device 34 includes a resistor R1 and a voltage across a main capacitor (not shown) of a strobe light emitting circuit in the strobe device 34, as shown in FIG. The voltage is divided by the voltage dividing circuit of R2 and input to the CPU 11. Note that the capacitor C1 is a capacitor for absorbing the ripple generated during charging, and the resistance values of the resistors R1 and R2 are selected by the CPU 11.
Is set so as not to exceed the input rating of.

In the lens shutter camera configured as described above, if the CPU 11 recognizes that the operation switch 19 is turned on while the flash device 34 is being charged, the CPU 11 reduces the voltage of the main capacitor in the light emitting circuit of the flash device 34. After attenuating by the division ratio determined by the resistors R1 and R2, the CPU 11
It is digitized by an A / D conversion circuit (not shown).
The correction of variations in the resistance values of the resistors R1, R2 are, because they are stored as correction data to the E ² -PROM14 is a nonvolatile memory, the charging voltage can be accurately detected.

Then, after A / D conversion, the CPU 11 immediately stops charging and shifts to aperture correction calculation. That is, the CPU 11 determines whether or not the light emission level is attainable in accordance with the detected charging voltage and calculates the number of steps for correcting the aperture opening diameter. At this time, the CPU 11 also determines whether or not the continuous shooting mode is set,
In the case of continuous shooting, the detection level is set to the lowest voltage at which light can be emitted. In the case of the lens shutter, since the sector blades also serves as a diaphragm and a shutter, wherein M _S integration start signal a signal for detecting that (shutter motor) 24 is started to rotate, i.e. AE trigger signal Thus, the time from the AE trigger to the flash emission timing is corrected.

Here, an example in which the detected charge level is divided into two levels of a full charge and a minimum voltage level at which light emission is possible will be described below. The time until the strobe light emission timing is as shown in FIG. If the strobe fires at the rising edge of the strobe trigger signal as shown in FIG. 5 from the distance to the subject, the film sensitivity information and the guide number at the time of full charge, the charging state has reached full charge. If there is no strobe trigger signal, the light is emitted at the rising edge of the strobe trigger signal with a delay from the timing of the strobe trigger signal. This delay is CP
The calculation is performed in U11. As the calculation method, for example, the delay amount may be determined so that the aperture value is reduced by one step at the time of full charge, that is, the aperture diameter is increased by one step. The calculation is performed in the same manner when the charging voltage detection level is two or more.

In the time chart of Figure 5, although the movement of sector blades AE trigger an integration start signal is not to follow, this delay be stored as data in the E ² -PROM14, it is compensated by this It has become so.

FIG. 6 shows an example of a flowchart of the flash charging process.

During normal shooting, when the power of the camera is turned on, charging starts and charging is performed until the camera is fully charged. The charge voltage is A / D converted and monitored, and it is checked whether continuous shooting is being performed and whether full charge is being performed. If full charge is completed, charging is stopped at "Y" and the process returns. If the full charge is not completed, the ON state of the release SW is checked. If the release SW is on, the charging is stopped. If the release SW is not on, the charging is continued.

Then, if the release switch is pressed before the full charge, the charge is immediately stopped because the release priority is given, and the charging process is terminated. Until the release process, the A / D conversion value of the charging voltage is checked and the strobe light emission process is performed as described above.

If the release is released while the release member is half-pressed, the process returns to the main loop and starts recharging.

In addition, continuous shooting by flash emission of release processing,
That is, if this process is called during the continuous shooting flash,
Since it is checked whether or not the voltage is capable of emitting light, charging is performed up to the voltage capable of emitting light and the charging is stopped. It goes without saying that the flashmatic control operation is also corrected in this case. Further, if the release is released during the continuous flash shooting, the continuous shooting process is terminated. In this case as well, charging is stopped once, but charging is performed again in the main routine, so that charging is apparently performed continuously.

Also, the reason for stopping charging at the time of other processing,
As is well known, during charging, the power supply voltage is reduced, so that when the other actuators of the camera are simultaneously operated, the voltage is further reduced and the CPU may run out of control. This is to prevent this.

Next, a description will be given of a flowchart of a release process, which is the basis of the camera operation shown in FIGS. 7A and 7B.

First, a photometric operation is performed as shown in the flow of FIG. 7A, and then a distance measuring operation is performed. Next, the photographing lens is moved to an in-focus position by AF (auto focus) processing. Here, it is checked whether the 2nd release SW is on, and if it is not on, the 1st release S
It is checked whether W is turned on. This 1st
If the release switch is on, turn on the 2nd release switch again.
Check. The 1st release and 2nd release switches are switches that turn on only the 1st release switch when the same push button switch is half-pressed, and turn on both the 1st release and 2nd release when fully pressed. That is, 1st release S by half-press
When W is turned on, the AF lock is set. Also, 1st release SW
When the half-pressed state in which is turned on is released, the release processing ends.

Then, when the second release switch is in the fully-pressed state of ON, the photographing operation is started. First, a battery check is performed to check whether or not the photographing voltage is attainable. If it is not possible, the operation is stopped here and the user is notified by an illustration display such as an LCD. If the battery voltage is the photographable voltage, then a check is made as to whether or not the camera is in a self-timer mode. If the mode is not the self-timer mode, the process proceeds to the next exposure process. In the case of the self-timer mode, a timer count is performed, and, for example, 12 seconds later, the process proceeds to the next exposure process. Here, if the self-switch is pressed while the timer is counting, the shooting mode is canceled and the routine returns.

In the exposure processing, a shutter opening / closing operation is performed. In this case, in the case of flash emission shooting, the flash is emitted here. After the exposure, the film winding operation is performed. At this time, if there is no film, a demowind is performed. When the winding process of one frame of the film is completed, it is next checked whether or not the mode is the continuous shooting mode. That is, as shown in the flow of FIG. 7B, it is checked whether the camera is set to the continuous shooting mode. If the mode is not the continuous shooting mode, the self-timer mode is reset, and the shooting ends.

Also, in the case of the continuous shooting mode, it is determined whether or not the strobe needs to be charged.
Looking at the state of the release SW, if the release SW is kept pressed, continuous shooting is performed according to the flow of FIG. 7 (a). When charging is necessary, the flash is charged.When the flash reaches the minimum voltage at which the flash can emit light, charging stops, the connector goes to the connector, the state of the release switch is checked, and the release switch continues to be pressed. And the seventh
Continuous shooting by flash emission photographing is performed according to the flow of FIG. Also, in the flashmatic control at the time of the flash emission photographing, it is needless to say that the aperture opening diameter is appropriately corrected by the flashmatic correction means in accordance with the charging voltage of the flash.

[Effects of the Invention] As described above, according to the present invention, in the case of continuous shooting by strobe flash photography, the charging voltage of the strobe is forcibly reduced to a voltage at which the flash can be emitted, so that the charging time is shortened. The continuous shooting interval is shortened.

The effect is obtained. Therefore, it is possible to eliminate the disadvantage that the charging time in the conventional continuous shooting is long.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram of the present invention, FIG. 2 is a block diagram of a main part of a camera having a flash device according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing a case where the strobe device of the present invention is applied to a fully automatic camera adopting FIG. 4. FIG. 4 is a block diagram showing the relationship between the CPU and the strobe device in the block diagram of FIG. Fig. 6 is a time chart showing an example of a flash timing and a flash level of the strobe, Fig. 6 is a flowchart of a flash charging process, and Figs. 7 (a) and 7 (b) are a flowchart of a camera release process. 101 Power supply 102 Boosting means 103 Capacitor 104 Flash discharge tube 105 Charge voltage detecting means 106 Boost control means

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-62038 (JP, A) JP-A-60-220322 (JP, A) JP-A-61-99125 (JP, A) JP-A-61-99125 138243 (JP, A) JP-A-58-30741 (JP, A) JP-A-56-114937 (JP, A)

Claims (2)

(57) [Claims] A strobe device incorporated in a camera capable of performing a continuous shooting mode in which exposure and automatic winding of a film are repeatedly performed and a normal shooting mode in which exposure and automatic winding of a film are performed once each time. Boosting means for boosting a voltage, a capacitor charged with the voltage boosted by the boosting means, a flash discharge tube emitting light by discharging a charge of the capacitor, a light emission minimum voltage of the flash discharge tube, Charging voltage detecting means for detecting a charging voltage of the capacitor at at least two levels of a voltage higher than the same voltage; and, in the normal shooting mode, the capacitor is fully charged by the boosting means; When the detecting means detects that the charging voltage has reached the light emission minimum voltage level, the boosting is performed. Comprising a step-up control means for stopping the boosting stage, and in the continuous shooting mode flash device being characterized in that so as to repeat the above charging operation for each frame photography. 2. The charge voltage detection means includes A / D conversion means, and determines whether a conversion value by the A / D conversion means exceeds the light emission minimum voltage level or a voltage level higher than the same voltage. The strobe device according to claim 1, wherein