JPH02242242A - Controller for stroboscope - Google Patents

Abstract

PURPOSE:To detect charging voltage in multi-stage by voltage-time converting the charging voltage of a capacitor for a stroboscope, generating a pulse and measuring the time width of the pulse. CONSTITUTION:When a voltage check signal CHCK is made H, a transistor Tr3 is turned on so as to perform the discharging of the capacitor C3 and the - side of an Ne tube is grounded through a resistance 4 and the Tr3. Therefore, the voltage of the resistance R4 on the Ne tube side is a value VF-VN which is obtained by subtracting the lighting holding voltage VN of the Ne tube from the charging voltage VF. Next, when the signal CHCK is made L and the Tr3 is turned off, the charging of the capacitor C3 is performed and the Tr4 is turned on, then an RLS becomes L. When the charging of the capacitor C3 goes on, the Ne tube is turned off and the current from the resistance R4 to the capacitor C3 does not flow, then the Tr4 is turned off and the RLS becomes H. Since a time when the RLS is L(the width of the RLS pulse) T is decided from VF-VN, the charging voltage VF is detected by detecting the pulse width T.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a strobe control device that controls charging of a camera strobe, and particularly relates to a device that can detect charging voltage at a fine level and use it for control. It is something.

[Prior art and problems to be solved by the invention] Conventional strobe circuits are used to determine whether the charging voltage of the main capacitor has reached a predetermined detection level, and to permit light emission or display. There is.

If the detection level is one level, detailed control according to the charging voltage is not possible.

On the other hand, in the case of multi-level detection, a configuration is adopted in which the charging voltage is divided and A/D converted, and it is determined individually whether each level has been reached, which requires a large circuit size. Not only is this disadvantageous in terms of space, but it also increases the cost due to the complexity of the circuit.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a strobe control device that can detect charging voltage in multiple stages with a simple configuration.

[Means for Solving the Problems] The present invention has been made to achieve the above-mentioned object, and claim 1 is characterized in that the charging voltage of a strobe capacitor is voltage-time converted to generate a pulse. Claim 2, characterized in that the charging voltage is indirectly measured by measuring the time width of the pulse, is characterized in that the pulse is output only when the charging voltage exceeds a predetermined reference value. Item 3 is characterized in that the reference voltage is a strobe light emission permission voltage. Claim 4 is characterized in that the pulse output means is turned on/off based on a check signal for checking the charging voltage of the main capacitor.
a switch means for FF; a hysteresis element having different characteristics for the energization start voltage and the energization holding voltage and to which the voltage of the main capacitor is applied when the switch means is turned on;
The switch means changes from ON to O while the hysteresis element is energized.
and a compensating means for compensating the energization of the hysteresis element while the voltage applied to the hysteresis element drops from the energization start voltage to the energization holding voltage after FF, and the time during which the compensating means compensates for the energization of the hysteresis element. Claim 5 is characterized in that a pulse corresponding to the
Claim 6 is characterized in that the hysteresis element is a neon tube, and claim 7 is characterized in that the compensation means is a capacitor. Claim 7 is characterized in that the hysteresis element is a neon tube. Claim 7 is characterized in that a plurality of strobe charging time-up times are provided, and the camera Claim 8 is characterized in that one charging end time is selected depending on the state of use of the battery, and charging is ended if the charging voltage does not reach a predetermined value even after the selected charging end time has elapsed. , prepare multiple types of strobe charging termination voltages, select one charging termination voltage according to the usage status of the camera, and start charging if the set charging termination voltage is not reached even after the predetermined charging time has elapsed. Claim 9 is characterized in that a plurality of charging end times and charging stop voltages are prepared. Claim 10 is characterized in that a voltage measuring means for detecting the voltage of a strobe capacitor; and exposure determining means for determining a corresponding appropriate exposure value based on the measured voltage.

[Example] The present invention will be explained below based on the drawings.

1 to 27 show an embodiment of the present invention.

First, the appearance of a camera equipped with a strobe control device according to this embodiment will be described with reference to FIGS. 1 to 3.

In FIG. 1, 1 indicates a camera body, and 2.3 indicates a zoom lens barrel. On the front side of the camera body 1, there is a second
As shown in the figure, a distance measuring section 4, a finder window 5, a strobe 6, a CdS as a light receiving element for photometry, and a self-timer lamp 7 are provided.
, an LCD display 9, a mode button A, a mode button B, a clear button C, a zoom lever 10, a green lamp D, a red lamp E, and a camera back opening/closing lever 11. When operated in the direction of the arrow toward the stop position, the back cover 8 is opened. When the back cover 8 is open, the back cover opening/closing lever 11 is at the lowering stop position, and when the back cover 8 is closed, the back cover opening/closing lever 11 is raised.

The back cover 8 is provided with a date display section 12 and a date switching button 13. Note that a rewind button (not shown) is provided at the bottom of the camera body 1.

As shown in FIG. 1, the top of the camera body 1 includes a main switch 14, a shutter button 15, and a macro button 1.
6 is provided. The main switch 14 is slid between an ON position and an OFF position.

The zoom lever 10 is moved between the wide side and the telephoto side as indicated by the arrow r1.
, r2 direction.

The zoom lens barrels 2 and 3 are operated by operating the main switch 14 and the macro button 16 to adjust the zoom range between the locked position, which is the stored state, and the wide end (focal length 35 mm) and telephoto end (focal length 7011I1 m). It is moved between the lens and the macro position for close-up photography, and in the zoom range, the shadow lens can be zoomed by operating the zoom lever 10.

FIG. 4 shows the circuit configuration of the above-mentioned camera.

The core of this control circuit is the main CPU, and a sub-CPU that performs shutter-related processing in parallel.
are connected via the drive IC.

The main CPU performs the following controls based on input from information input means such as switches.

(1) Control the zoom motor and film motor via each motor drive circuit.

(2) Controls lighting and blinking of the green lamp for distance measurement related displays, the red lamp for flash related displays, and the self-timer lamp 7 for self-timer related displays.

(3) Control the display on the LCD display 9.

(4) Control charging of the strobe circuit.

As a means of inputting information to the main CPU,
There are the following:

(1) A lock switch LOCK that is turned on when the slide lever of the main switch 14 is set to the lock position.

(2) Photometering switch SWS that is turned on by pressing the shutter button 15 one step.

(3) Release switch SwR0 that is turned on when the shutter button 15 is pressed in two steps. (4) A self-back macro switch MCRO that is turned on when the macro button 16 is pressed.

(5) Zoom teleswitch position E, which is turned on by tilting the zoom lever 10 to the telephoto side r2.

(6) Zoom wide switch WI DE, which is turned on by tilting the zoom lever 10 to the wide side r1.

(7) Self-back mode A switch M that is turned on by pressing each mode button A, B, or clear button C
DA, mode B switch MDB, clear switch M
χ.

(8) Push down the back cover opening/closing lever 11 to turn OFF L;
, turns ON when the back cover 8 is closed and the lever is raised to the lock position.
Press the back cover switch BACK.

(9) Self-back rewind switch REW that is turned on by pressing the rewind button.

On the other hand, the sub CPU controls a distance measurement unit consisting of an infrared LED and a PSD via an autofocus IC, and also outputs distance measurement data based on the output of the autofocus IC and photometry data based on the output of the CdS. Main C
Transfer to PU.

The drive IC controls the shutter circuit and trigger signal TR of the strobe circuit based on commands from the sub CPU.
Outputs G.

Details of the strobe circuit are as shown in FIG.

In addition, in FIG. 5, the main CPU and sub CPU are displayed together.

This circuit is centered around the CPU, and uses battery B by charging etc.
A regulator that stabilizes the voltage supplied to the CPU regardless of voltage changes on the ATT, and a charging permission signal CH from the CPII.
A booster circuit that boosts the battery voltage using EW and starts charging the main capacitor C1, a trigger circuit that causes the Xe (xenon) tube to emit light based on the trigger signal TIIG from the CPU, and a voltage check signal C day CK from the CPU. It is composed of a voltage detection circuit that detects the charging voltage of the main capacitor as an RLS pulse.

The step-up circuit includes a step-up transformer and an oscillation transistor T.
It is composed of r1, Tr2, resistors R1, R2, R3, a capacitor, and diodes Di and D2, and starts charging when the charge permission signal CHEW becomes L (Low Level), and stops charging when it becomes open level.

The voltage detection circuit includes a Ne (neon) tube for determining a reference voltage, a switching transistor Tr3, a transistor Tr4 for RLS pulse generation, and a resistor R4.
~R8, and a capacitor c3, and generates an RLS pulse proportional to the voltage when the check signal CHCK changes from )l (High Level) to L.

The Ne tube shown here lights up when the voltage exceeds 270V, and turns off when the voltage falls below 220V. This hysteresis between the lighting start voltage and the lighting holding voltage is utilized to generate the RLS pulse.

Here, the principle of voltage detection will be explained based on FIG. 6.

When the check signal CHCK is set to H, the transistor T
r3 is ONI, and the negative side of the He tube is connected to the ground side via a resistor R4 and a transistor Tr3. At this time, if the charging voltage VF is 270V or more, CHCK is high.
After the lighting delay time has elapsed, the Ne tube lights up, and current flows through the Ne tube, R4, and τr3 in this order. Therefore, He'd! of resistor R4! The voltage of H is the value VF-VW obtained by subtracting the lighting holding voltage VW of the Ne tube from the charging voltage VF.

Next, the check signal is set to L, and the transistor Tr3 is turned to O.
When the transistor Tr3 is turned off, the current flowing from the resistor R4 to the transistor Tr3 flows from the resistor R4 to the capacitor C3 for a while. As a result, the capacitor C3 is charged and the transistor Tr4 is turned on, so that the potential on the collector side of the transistor Tr4 falls to the ground level, and R
LS yells at L.

As the charging of the capacitor C3 proceeds, the potential of the capacitor 03 of the resistor R4 gradually increases, and it becomes impossible to apply the lighting holding voltage VN to both ends of the He tube. As a result, the He tube goes out and the current from the resistor R4 to the capacitor C3 also stops flowing, so the transistor R4 turns off and RLS
becomes H. However, the timing at which the transistor Tr4 is turned off is earlier than the time when the Ne tube is turned off, which is determined by the value of the resistor R7.

The higher the charging voltage VF is, the later the timing of extinguishing the He tube is proportionally delayed, so the time T during which RLS is at L (the width of the RLS pulse) is proportional to (VF-VN).

Therefore, by detecting this pulse width T, the charging voltage VF can be detected.

FIG. 7 shows an example of the relationship between charging voltage and RLS pulse width.

Note that if the charging voltage is 270V or less, the lle tube will not light up even if the transistor Tr3 is turned on.
RLS remains at H.

Next, the functions of mode button A and mode button B will be explained.

Mode button A has the function of setting the exposure method, and the exposure methods include auto (strobe automatic firing mode),
Strobe ON (Strobe forced flash mode), Strobe 0
FF (flash off mode), exposure compensation, bulb,
Six types of valve and strobe ON are available.

When the exposure method is bulb or bulb & strobe ON,
8 types of manual setting time is t1! Equipped with

The mode button B has a function of setting a shooting method, and six types of shooting methods are prepared here: single-frame shooting, continuous shooting, self-timer, double self-timer, multiple shooting, and interval shooting.

Sixteen types of interval times are prepared for the intervals of the imaging method.

Note that the initial value of the manual shutter time is bulb, and the initial value of the interval time is 60 seconds, which are set by executing the mode initialization process or by turning on the clear button.

Next, the program stored in the main CPU mentioned above will be explained along with the operation of the camera according to the flowcharts shown in FIGS. 8 to 27.

(Main Processing) First, the reset processing and main processing shown in FIGS. 8 to 13 will be explained. The main process defines the basic operation of the camera, and other processes are branched from or called from the main process depending on various conditions.

When the power is turned on, the main CPU is reset, and the reset process shown in FIG. 8 is started. The main CPU performs memory initialization and switch data input in steps R3I and RS2 (hereinafter referred to as S), mode initialization processing in S and R33, and zoom initialization processing in S and R34, and then Enter main processing. Note that the mode initialization process is a process for returning the settings of the various modes described above to their initial values, and setting the mode to automatic strobe light emission and single-frame photography.

In the main process, a 1 second display timer is cleared and started in S and Mll.

S, MI2 to MI4, photometry switch SWS, release switch SWa, wide switch WIDE,
Teleswitch position E, mode A switch MDA, mode B switch MDB.

Is the switch judgment flag set when clear switch Hχ and macro switch MCRO are all OFF? 5WO
1 is set in FF, and 0 is set if any of them is ON. In the following description, flag names are distinguished from other symbols by adding a "?" to the beginning of the word.

In S, MI5 to HI8, all four switches, metering switch SWS, release switch S, wide switch WIDE, and telephoto switch H are OFF, and a mode combination is selected in which shooting is prohibited in the mode setting. Is the metering switch enabled flag if not? 5w5
EN is set to 1, and any switch is set to 081.
is set to 0, or when a mode combination that prohibits photography is set.

In S and MI9, the status of each switch mentioned above is input,
Thereafter, processing is performed based on this input switch data.

First, in S, Mllo, rewind switch REW
is determined to be ON, the mode is initialized in S and old 11, and then the first mode is initialized in S and R112.
The loop extraction process shown in Figure 0 is performed. This process consists of two processes: a strobe circuit charging stop process S, LO1, which will be described later, and a process S, LO2 that turns off the red lamp for charging display.
It consists of steps and is always called before branching from main processing to other processing.

After the loop extraction process, the process branches to the rewind process.

I won't go into details about the rewind process, but when the film finishes rewinding, is there a rewind end flag? REWEN
D is set to 1, and the process jumps to the beginning of the main process.

When the back cover is closed and the back cover switch BACK is ON, the loading end flag is set in S and Mll4.
Determine whether loading is finished from the state of LDEND, and if it is not finished (?I, DEND, O
) has S, Mll5. The process branches to the loading process through the mode initialization process and the loop extraction process of Mll6. If finished, S, Mll7.811
8 is skipped and the process proceeds.

Furthermore, what happens when the loading process is finished? LDEND is set to 1, and the process jumps to the beginning of the main process.

If the back cover is open, S, Mll7, 8118
At? LDEND? REVEEND is also cleared.

S and M119 to MI24 in FIG. 11 show processing when the lock switch LOCK is ON, that is, when the main switch is turned OFF. If it is determined that the photographing lens is not in the lock position, the film number display on the LCD display is switched to the focal length display, the extraction process is performed, and the process branches to the zoom reversal process to return the lens to the lock position. If the lens to be pulled back is already at the lock position and the rewind is not yet completed, the process branches to the locking process to be described later through the loop extraction process. If the rewind is completed, the process jumps to the rMIDJ position of the main process shown in FIG. 13 and proceeds.

The lock switch LOCK is OFF, and S,
If MI25 determines that the lens is in the locked position, S, MI26. In addition to displaying the focal length on the old 27, the display hold flag? WAITD 1
Set the display to hold for 1 second. This hold processing will be explained at the end of the main processing. After that, S, MI28 macro request flag? 0 to RQMCRO
is set, the extraction process is executed at S and MI29, and the process branches to the zoom normal rotation process. Macro request flag in zoom forward processing? If RQMCRO is 0, the lens is moved from the lock position to the wide end, and this flag is set to 1.
If so, move the lens to the macro position.

S, M130 to MI38, macro switch MCRO
is ON, the focal length is displayed and the display hold flag? Set WAITD to 1. Then, it is determined whether or not the photographing lens is in the macro position, and if it is in the macro position, the display hold timer is cleared and started, and the process jumps to rMIcJ in FIG. 13 to proceed with the process. If it is not in the macro position, is it a macro request flag? R
QMCRO is set to 1, loop extraction processing is performed, the process branches to zoom forward processing, and the lens is moved to the macro position.

Next, in S, MI37 to MI43 shown in FIG. 12,
When tele switch position E is ON, it switches to focal length display and sets the display hold flag, and if it is not at the tele end, it goes through extraction processing to determine whether the lens is in the macro position or in the zoom range. to decide. If it is in the zoom range, it branches to telephoto movement processing to be described later to move the lens to the telephoto side, and if it is in the macro position, it branches to zoom reversal processing to return the lens to the telephoto end.

If the lens is already at the telephoto end, the display timer is cleared and the 1 second count is started again from this point.

S, MI44 to MI50-C' are wide switches WI
If DE is ON, switch to focal length display and set the display hold flag, and if the lens is at the wide end, use S, MI48 to start the timer and proceed with the main processing. If it is not at the wide end, it is determined whether the lens is at the macro position or in the zoom range through loop extraction processing.

If it is in the zoom range, the process branches to wide movement processing to move the lens to the wide side. If it is on the macro side, it branches to zoom reversal processing and pulls the lens back to the telephoto end.

Therefore, the photographing lens is set to the macro position by turning on the macro switch, and the lens set to the macro position can be returned to the zoom range by operating the zoom lever in either direction.

In S and 151 to M+54 in Fig. 12, is the macro tele shift flag? If it is determined that a shift is requested from the MTSIFT state, focal length display processing is performed and the display hold flag? WAITD is set to 1, and after loop extraction processing, the process branches to zoom reversal processing and returns the lens to the telephoto end.

The long distance limit for macro photography is approximately 1 meter, so if the lens is in the macro position and the distance measurement result is 1 meter or more, you will not be able to obtain a focused photo even if you release the shutter.

Therefore, in this camera, the release lock is applied in the above case, and the lens is controlled to be shifted from the macro position to the telephoto end. flag? HTSIFT is I
This is set in the LL calculation process within the IAF control process.

Next, S, MI55, rewind end flag? R.E.
The state of WEND is determined, and if the rewind is completed, S and roOEX are displayed on the LCD display using the old 56. If this flag is 0, mode setting processing is called in S, MT57.

In the mode setting process, the switch judgment flag set in S, MI2 to M14? Checking 5WOFF, if all the switches were set to 0FFj in the previous input, the setting process is entered, and if any switch was turned on, the process returns to the main process without setting.

If there is a mode change during this mode setting process, the mode change flag? 14DC) IG is set to 1,
If there is no change, it is set as O.

When returning from the mode setting process, the state of the flag set in S, 158 is determined, and if there is a mode change, S, HI39. At HI60, the display hold flag is set to 1, and the process jumps to the beginning of the main process through the loop extraction process.

If there is no mode change, S, HI61. H
Is the photometry switch SwS and the photometry switch valid flag in I62? Determine the status with 5WSEN, and if predetermined conditions are met, display the focal length with S and MI63 to 8165, clear the display hold flag, and control the shutter intermediary through loop extraction processing ^ EAFM gl
Branches to J processing.

A! Branching to tAF control processing occurs when the photometry switch is OFF.
313, SWl'
This is a case where the switch data of l, TEI, E, and WrllE are all OFF and the mode setting is such that photography is possible. That is, the process branches to the AEAF control process only when SwS changes from OFF to ON, and if the zoom lever is being operated, etc., the main process continues without branching.

In S, HI66, the charging control process described later is called,
S, display switching processing is executed in MI67 to MI71.

If display hold is requested, it is determined whether one second has passed since the display timer was cleared.

Before the timer elapses for 1 second, the currently displayed display is held.

If display hold is not requested, or when the timer elapses for 1 second, if a display other than the number of sheets is being displayed, the number of sheets is displayed, and the display hold flag is set? W.A.
Clear ITD.

In this way, the film number display is displayed preferentially over other displays, except when switched from time to time.

Then, after stopping the processing for 125+ms at S, HI72, S.

At 8173, charging prohibition time processing, which will be described later, is called, and after returning, main processing S, ? The process jumps to step 112 and continues processing.

In order to prevent the strobe circuit from heating up due to continuous use of the strobe, as will be described later, this camera prohibits the start of charging for a predetermined period of time when the flash frequency is high.

The charging prohibition time process is a process for shortening the prohibition time set when the strobe is not used.

This concludes the explanation of each step of the main processing, and then the flow and subroutines branching from the main processing will be explained.

(Charging Control Process) The charging control process called in the main process S, HI66, the release waiting charging process, and the interval control process, which will be described later, will be explained based on FIG.

This process is the main process in charging execution, and is called every 125 m5 cycles in any process.

In S, CC1, is the prohibition time completion flag? It is determined whether the charging prohibition time has elapsed based on the FW CMP, and if it has not elapsed (0), the charge prohibition process described below is executed at S, CC2, and then the charging prohibition time is executed at S, CC3. flag? Determine whether or not it is during prohibited time from the state of FWτ5Tli. 4M If it is determined that it is during regular time (1), S.

The process branches to CCV and charging stop processing is executed.

Charging prohibition time is completed and prohibition time completion flag? F.W.T.C.
If MP is 1, or is the prohibition time flag completed during prohibition processing? When FWTSTR is set to 0, the charge request flag is set at S, CC5? C)I
Determine the GRQ status, and if there is a charging request, S, C
If there is no C6, the process advances to S and CC4.

In the charging stop process, the prohibition time reduction prohibition flag in S and CC4? Set FCNTSTP to 0 to allow shortening of the charging prohibition time in the charging prohibition time processing described later, and S,
At CC7 to CC9, charging and voltage checking are stopped, the red lamp is turned off, and the process returns to the called step.

When a charging request is made, a timeout flag is set in S and CC8 during the timeout check process described later.
Based on the state of FTOUT, it is determined whether 8 seconds or more have passed since the start of charging, and if so, S, CC10
Charging flag inside? FC) IG and prohibition time completion flag?
FWTCMP and charging request flag? C) Stop charging after clearing IGRQ.

If 8 seconds have not passed and before charging starts, press S.
, Charging flag in CC11 to CCl3? F.C.H.G.
The charging time timer is started by setting 1 to 1, and the voltage check is started while charging is prohibited. This is because the charging voltage at the start of charging is unknown, so the voltage is determined before charging is performed.

If charging is in progress, branch from S and CC11 and connect to S.
, CC16 and CC17 execute RLS pulse time measurement processing and timeout check processing, which will be described later, and set a charging completion flag during image processing. It is determined whether charging is completed based on the state of FCCMP. Note that this flag is
Normally, the charging voltage is 330 in the RLS pulse time measurement process.
When the voltage exceeds V, it is set to 1, but after 8 seconds from the start of charging, it is set to 1 at 270V.

If charging is determined to be completed, charging stop processing is executed via S, CC10, and if charging is determined to be incomplete, S, CC19 to
Issue charging permission and voltage check with CC21 and return.

Therefore, at the start of charging, S, CCl2 to CCl3
Execute the process once and after 125m5 S, CC16~C
Charging is started through the process of C21. S while charging,
Repeat the processing of CC16 to CC21, and when finished, S,
Processes CC7 to CC9 are executed.

(Charging Prohibition Process) FIG. 15 shows the charge prohibition process called in S and CC2 of the charge control process.

This process is called when the charging prohibition time has not been completed, and the 6M stop time TV, which counts the prohibition time while comparing the prohibition time TW and the prohibition time timer, is used for RLS pulse time measurement processing and charging. It is determined based on the prohibited time data n set in the prohibited time process.

If it is determined in S, C31 that the prohibition time timer has not started, the prohibition time timer is started in S, C32, and CS3, and the prohibition time flag is set to 1, and charging is performed in the charging control process shown in FIG. Set to stop.

For S, C84 to C88, the prohibition time data n is 5.
If it is greater than 0, is there a flag to set the prohibition time to 10 seconds to uniformly set the prohibition time to 10 seconds? FWT11]S is set to forcibly set data n to 50, and if it is larger than 7 and smaller than 50, clear this flag and return.

If the prohibited time data n is 7 or less, S, C39
~C3lI cancels the prohibition time processing and returns.

If this process is executed after the prohibition time process is started, the process proceeds from S, C81 to S, C312.

S, C3i1! According to ~cst, if the prohibition time data n is 50 or less, the prohibition time TW is set to nX 12
5m5, and determines whether the prohibited time timer started at S and CS2 has exceeded the prohibited time τ, and if the prohibited time data is greater than 50, determines whether the prohibited time timer has exceeded 10 seconds. to judge.

Before the prohibition time timer exceeds TW or 10 seconds, return as is, and if it exceeds, S, C39 to C3l
Press I to complete the prohibited time and return.

(RLS Pulse Time Determination Process) FIG. 16 shows the RLS pulse time measurement process called at S, CC16 of the charging control process. This process converts the charging voltage of the strobe main capacitor into voltage-time and measures it as a pulse time.

In S, RL1 to RL4, after the voltage check signal is set to L, it is determined whether RLS becomes L before the 2 ms timer times up.

As mentioned above, RLS becomes L when the charging voltage is 27
This only occurs when the Me tube lights up when the voltage is 0V or higher, so if it is lower than that, clear the charging voltage 270V and 280V flags in S, RL5, and RLS.
Return DGV as 0/4Ev.

The strobe capacitor is fully charged at a voltage of 315V, and the guide number is determined based on the amount of light emitted at this time. On the other hand, with this camera, even if the capacitor is not fully charged, it may emit only the amount of light that has been charged. Therefore, if the voltage has not reached 315V, you must be aware of the decrease in guide number due to the voltage drop, or the DGV will be underexposed.
is a parameter that indicates the decrease in guide number due to strobe charging voltage drop, and is 274.28 at 315V or higher.
In the case of 5v to 315v, 1/4.285v or less is O/4
is set to the value of

If RLS becomes L before the 2+as timer times up, that is, if the charging voltage is 270V or higher, measure the time until RLS becomes H using the RLS pulse timer at S, RL7 to RL9. and set the pulse time T.

When proceeding to S, RLlo for the first time after RLS becomes L, execute the processing of S, RL11 to RL14 once, and set the measurement reference time T1. Average value T of saved past T1
After determining T1 with emphasis on IAV, the newly determined T1 is determined as a new average value TIAV, and 2 is added to the prohibited time data n.

If RLS goes low before 500 m5 has elapsed from the start of the charging time timer, T1 is set to the value of TIAV. However, in this case, it is determined that the charging time is short and the temperature rise of the transformer is small, so that the prohibited time data n is not performed.

The charging voltage VF and the RLS pulse time have a certain relationship as a design value, as shown in FIG. but,
There may be some variation between products. Therefore, by averaging the values of the first R1 and S pulses, which are considered to correspond to a charging voltage of 270V, for each charging time and adding them to the evaluation of the pulse time, we can eliminate the disparity due to product variations in voltage detection. The configuration is such that it is corrected.

S, I'll, 15. RL16m' has a charging voltage of 280
V7-y? Clear FCH280 and DGV O/4
Charging voltage 270v flag as Hv? 1 FCH270
shall be.

RL from the second time onwards after the charging voltage becomes 270V or higher
In the S pulse time measurement process, the charging voltage is determined by comparing the latest RLS pulse time T with the voltage corresponding time in S, RL17 to RL25.

The voltage compatible time is 330 for TI/2+800 us.
v, 1/2 + 700 μs is 3157. Tl/2
+500μs is 285V, and Tl/2+400μs is 280V. The above-mentioned FIG. 7 shows an example in which T1 is 300.

If the voltage is 330V or higher, is it a charging completion flag? F.C.C.M.
Let P be 1. Then, a DGV corresponding to the voltage is set, and if the charging voltage is 280V or higher, both the charging voltage flags are set to 1 and the process returns.

If tearing is less than 280v, S, RL15. Return via RL16.

(Timeout Check) FIG. 17 shows the timeout check process executed at S and CC17 of the charging control process.

This process defines the upper limit of the charging time based on the measurement time of the charging time timer started in S and CCl2 of the charging control process.

This process consists of steps S, 701 to 09,
Is there a time-up flag if charging continues even after the charging timer has elapsed for 6 seconds? Set FCRTUP to 1. Also, if 8 seconds have passed and the charging voltage has reached 270V, the charging completion flag? FCCMP is set to 1, and if the timeout flag 7FTOUT has not been reached, the timeout flag 7FTOUT is set to 1 and the process returns. When the timeout flag is set,
Charging is stopped during the charging control process.

(Charging Prohibited Time Processing) FIG. 18 shows the charging prohibited time processing that is executed in S, 14T73 of the main process and the locking process to be described later. This process is a process of subtracting the set prohibition time data n when the camera is left unused and the strobe is not used, thereby shortening the prohibition time tW.

Ban time reduction ban flag? If it is determined from the state of FCNTSTP that shortening is prohibited, that is, if the charging prohibition time is being counted or if time has expired, the process returns from S and TCl without performing any processing.

If shortening is not prohibited, clear the flag,
If the prohibited time data n is 0, the prohibited time shortening prohibition flag is set to 1 and returned at S, Te3, and the setting is made so that n will not be subtracted from the next call.

If the prohibited time data n is not 0, a 4-second timer is used in S, 706 to C12, and 1 is subtracted from n every time the prohibition time data is left unused for 4 seconds.

That is, the prohibited time data n is not subtracted only when n becomes 0.

(Lock Processing) FIG. 19 shows the flow of lock processing branching from main processing S and MI24. This process is branched and executed when the lock switch is turned on and the photographic lens is housed in the lock position.

When this process starts, the loading end flag is set to 4 in S and LK1 to L? Depending on the state of LDEND, the number display is turned on or off on the LCD display, and the mode is returned to its initial value.

S, the loop from LK5 to LK13 requires that the rewind switch REw is OFF and that the back cover switch BACK
It is executed repeatedly at intervals of 125m5 on the condition that the lock switch is turned OFF or loading is completed even if it is in OII, and the lock switch is turned ON.

S, LK12. In LK13, main processing S, HI7
Charging prohibition time processing similar to 3 is performed.

When the rewind switch is turned on,! li, L.K.
8, the process branches to the rewind process described above.

If the back cover is closed and loading is complete, S, LK9. A loop is formed by skipping LKlo, and when the back cover is opened, the loading end flag is cleared and the sheet number display is turned off. When the back cover is closed in the next loop, the process branches to the above-mentioned loading process from S and LK8.

If the lock switch LOCK is OFF, S
, LK14, LK15 are charge request flags? C) IGRQ
and display hold flag? WAITD is set to 1 as the main capacitor, and processing proceeds.

When returning from lock processing to main processing, the main capacitor is often discharged, so by making a charge request, AE
Charge the battery before starting AF processing.

(AEAF control processing) Next, based on FIGS. 20 to 22, S of the main processing,
The AHAF control processing related to shutter control that branches from Mr65 will be explained. This process is entered when the photometry switch SwS changes from OFF to ON and the mode combination is appropriate as described above, but in addition to this, there is also a time when the Lease standby charging process is entered. AEA is applied to each branched ridge or after winding during continuous shooting.
This process is entered from the F control 2 and AIIAF control 3 terminals.

First, in S, AF1 to AF3, depending on which process this flow is entered from, the photometry distance measurement jump flag? AEA
Set F. If the AEAF control process branches to the release wait charging process and then returns to this process, these processes must be stopped because the detection of photometry, distance measurement, etc. has already been completed, as will be described later. for?
A! IAF is set to 1, and other cases are set to O.

When branching from the main process, S, AF4. AF5
Auto release flag? According to the state of At1TOIIEL, when this is O, the focal length is displayed. This flag is set to 1 when taking the second picture in interval mode or double selfie mode, as described later, and in these cases, the metering switch S is set to 1.
To automatically execute photography even if WS and release switch SWR are OFF.

In S and AF6, a voltage check process, which will be described later, is executed.
Measure the charging voltage of the main capacitor for the strobe.

S.AP? So, what about the charging request flag set in the FM calculation described later? Set CHGRQ to 0.

S, ^P8 ~ AFII, when this flow is entered from main processing or wind processing and is not the second image of interval or double self, distance measurement data is input from the sub CPU and L is calculated based on this. [, Performs (lens latch) calculation.

In cases other than the above, the previous LL data will be used as is, and therefore, in the case of interval shadows, etc., the focus will be the same as that of the first image. This is because, in the case of interval photography, the photographer is generally away from the camera, and it is necessary to prevent out-of-focus when the subject moves from the distance measurement area at the center of the screen.

The LL calculation is a calculation that determines the amount of lens movement for focusing based on the distance measurement result.

Also, in the LL calculation, if the lens is in the zoom range and the subject is close, a warning green lamp flashes flag? Set GLMPFL to 1 and set the release lock flag? Set RLOCK to 1. If the lens is in the macro position and the subject is far away, the above 2
macro teleshift flag in addition to two flags? MTSI
Let FT be 1.

In S, AF12 to AF16, except when the AEAF process is re-entered from the release wait charging process that branched -
Photometry-related processing is executed.

That is, in S, AF13, the DX code is input and the ISO sensitivity of the film is converted to the Sv value used for calculation, and S,
In AF14, the correction amount α of the open F number is determined from the focal length of the lens. Then, these data and S, AF1
Based on the photometric data input from the sub CPt1 in step 5, AE (automatic exposure) calculation processing is executed in S and AF16 to obtain kE data.

In S, AF17, FM (Flashmatic) calculation processing shown in FIG. 24 is called and FM data is set. Note that if this process is entered again from the release wait charging process that branched -, the AE calculation will be skipped, but since the DGV may have changed due to charging, the F
The M operation is to be executed again.

Next, check whether the release lock was applied during the LL calculation of S, AF11 or not with the release lock flag in S, AF18. Determine from the RLOCK state. Relay lock is applied when the lens is in the zoom range and the subject is too close, and when the lens is in the macro position and the subject does not move. In these cases, a photograph in focus cannot be obtained, so a warning is issued by flashing the green lamp in S and AF19 to AF21, and the metering switch Sw
Wait until S is released, turn off the red and green lamps, and jump to the main process.

For S, AP22 to AF24, if the charging voltage of the strobe capacitor has not reached the predetermined value and a charging request is made, the condition is that the strobe capacitor is not in interval mode, or even if it is in interval mode, it is the first shot. Then, the process branches to the release waiting charging process shown in FIG. In other words, from the second interval onwards, even if the charging voltage has not reached the predetermined value, only the amount of light that has been charged is emitted.
The following release sequence is executed.

At intervals, as shown in Figure 27, charging control is performed for each shot, and if this control does not reach a predetermined value, there is little possibility that the voltage will rise even if the charging process is performed again. It is from.

S, AF25 to AF27 output each set data to sub CPt1.

In the case of automatic shooting, the lamp display, metering, and release switch judgment are skipped and the
Jump to J. During normal shooting, not in automatic shooting mode, S, AP29. In AF30, when the strobe is to emit light based on the FM data, a red lamp is turned on, and the process proceeds to rAFBJ in FIG. 21.

For S and AF31 to AF33, the green lamp blinking flag is set inside the I and L calculations. Turn on or blink the green lamp based on GLHPFL. Here, when the green lamp is lit, photography is permitted, and when it is blinking, it is a warning.

For S, AF34, and AF35, the release switch SW is
It waits for R to be turned on, and when the shutter button is released, turns off the red and green lamps with S and AF34a, and jumps to the main process.

For S, AP36 to AP43, the 33 timer is started for the first shot in interval shooting, the 10s timer is started for the first shot in self-timer or double self-timer mode, and the 10s timer is started for the second shot in double self-timer mode. 58 Start the timer.

If it is the second or subsequent interval sheet, the interval timer is already running, so just press S.

^ Proceed to time count processing after F44, and if it is neither interval nor self mode, rA in Figure 22
Jump to FcJ.

S, AF44 to AF54 are loops that wait for the above-mentioned interval timers 10s, Sg, and 3s timers to time up, and can be exited by operating the mode button in addition to time up; in this case, S, ^
F55. When the red, green, and self-timer lamps are turned off using AF56, the automatic shooting flag is cleared, the mode is initialized, and the process jumps to the main process.

In the second and subsequent intervals, the remaining time of the interval timer is displayed.

Also, interval timer, 3s, 5s.

1 (When the remaining time on the 1g timer is less than 3 seconds, the self-timer lamp blinks at 4Hz.

When it comes to time up, S, Ar57. Based on the judgment in Ar58, if it is a self-timer, leave it as is, or if it is a double self, set it to S, and set the auto-release flag in Ar59? After inverting AIJτ0IIKL, proceed to ``^FC,'' in Figure 22. In the case of double selfie, the flag is set from 0 to 1 for the first shot, and returned from 1 to 0 for the second shot. Cancel shooting.

In the case of interval, start the interval timer at the interval time set in S, AF60 to AF64, set the maximum number of shots to 40 for the first shot, and start the second and subsequent shots. In order to do this automatically, set the auto release flag to 1.

When taking the second and subsequent shots, set the remaining time display on the LCD to "O3" and proceed to rAFC in Figure 22.S
, Ar64 is performed to prevent the display from returning to a number other than 0 due to time-up of the timer.

In steps S and AP65 to AF67 in FIG. 22, each lamp display is turned off when starting exposure, and a shutter start signal is output to the sub-CPIJ. S, AP6g, Ar
In No. 69, date imprinting is prohibited in the case of multiple photography.

If it is not the bulb mode, the process branches from S, Ar70, confirms that a shutter operation end signal is input from the sub CPU at S, Ar71, and proceeds to the winding process shown in FIG.

When in valve mode, S, sub-C with Ar72
Check that the shutter release signal is input from the PU,
In S, Ar73, it is determined from the contents of MODBLB whether it is an original bulb or a manual shutter. In the case of valves, S, Ar74. Wait for your hand to release the shutter button at Ar75, then press S, Ar76.
outputs the shutter close signal. If the shutter is a manual shutter, the manual shutter time is counted in S and Ar77, and a shutter close signal is output after the count ends.

(Voltage Check Process) FIG. 23 shows the voltage check process called at S, Ar1 of the ^IIAF control process.

s, vct~VC4, voltage check signal C) ICK
After setting it to H, take into account the rise of the He tube and add 50 mg.
After waiting, the RLS pulse time measurement process described above is executed.

S, VO2~VC71' C, If the charging voltage is 270v or higher and the mode is other than double self or interval, is the prohibition time shortening prohibition flag? FCIITSτP is cleared, and in other cases, the process directly proceeds to s and vcs. Therefore, when in a mode such as double self, the prohibition time is not shortened.

After that, charging flag with s and vca? FCHG and charging completion flag? Clears both FCCMP and returns to LEAF control processing.

In addition, the charging voltage 270 set during this voltage check
V7 lag? FC) lG270t: J: '), charge request flag in the FM calculation described later? CHGRQ is set, thereby branching to release waiting charging processing.

(FM calculation process) Figure 24 shows S, AFL? of the AEAF control process. This shows the FM calculation process called in .

This process determines whether the strobe emits light or not, and determines the aperture value AVH when flashing.

For S, FM1 to FM5, the exposure method is strobe OFF,
Exposure compensation, bulb, or auto)
If non-emission is determined in the E calculation process, the FM data is treated as non-emission and returns to the AIIAF control process.

In cases other than the above, calculate the aperture value Avs from the distance measurement data (AF step) and the standard guide number with S and FM7, and correct the aperture value Avs by taking into account charging voltage information DGV with S and FM7. . This is because the above guide number is set based on the strobe capacitor being fully charged, so unless the guide number decreases when the voltage is low, it will be underexposed.

For S, FM8, film sensitivity Sv is added to the aperture value Avs, and S, FM9. With FMIO, the guide number changes due to the strobe's own zooming when it is in the zoom range 1
Add 1ZDGV.

Furthermore, in S and FMll, the amount of change α in the open F-number based on the focal length of the lens is subtracted from the aperture value Avs.

For S, FM12 to F old 4, the upper and lower limits of the aperture value Avs are limited, and S, AF of the AEAF control process is
Based on the result of the voltage check process called in step 6, the charging request flag is set when the strobe capacitor voltage is less than 270V? Returns with CHGRQ set to 1.

(Release wait charging process) FIG. 25 shows S, AP23. of the AEAF control process. ^F2
4 shows the release waiting charging process branching from 4.

S, C) 11 to C1 (9 is S, CH6 charging control 1
This is a loop that is repeatedly executed in 25m5 cycles,
Charge time up flag set during this charge control process? FCHTUP and 280v charging flag? FC8
If the time is up from 280V or if it is determined that the voltage is 280V or higher, it can be removed.

In addition, in the case of automatic shooting such as interval mode, by turning on any mode switch (mode button A, mode button B1, clear button C), S,
C) It is possible to exit to 110, and when the camera is not in automatic shooting mode, it is possible to exit when the shutter button S is released.

Even if the charging voltage does not reach 280V within a predetermined time and 6 seconds pass and time-up occurs, the release waiting charging process can be exited. If these excerpts are taken out, S,
In CH10 to CH12, the red and green lamps are turned off, a charging stop process is performed, automatic photography is canceled, and the process jumps to the main process.

When the charging voltage reaches 280V before time-up, S, CI (S, CH1 after 13 charging stop processing)
Proceed to 4-CH16, and if it is not in automatic shooting mode, turn on the red lamp to indicate that it is ready to fire, and check the charging request flag? CI (Clear GHQ and 2nd
Jump to AEAF control 2 in Figure 0. From this process A
When EAF control is entered, as described above, photometry, distance measurement, etc. are omitted and calculations are performed using the previous data.

In addition, the voltage check during charging is based on 280V, and the voltage check after charging is based on 270V.
This takes into consideration the voltage drop caused by stopping charging, noise, etc.

In charging control performed within the main process, charging voltage 330
Charging is completed with v, and time-up is also monitored at 8 seconds. However, in the release standby charging process, the photographer is waiting for charging to end while pressing the photometry switch SWS, so charging is completed at a charging voltage of 280V and time-up is monitored at 6 seconds. Therefore, is charging requested at S and CC10 in the charging control process? C) Since IGRQ is not cleared, it is cleared in S, C)116.

(Winding Process) FIG. 26 shows the winding process that is carried out after the AEAF control process ends.

The winding process is a process for winding the film by one frame after shooting is completed.

When the winding process is started, the number of frames is displayed on the LCD display excluding the interval in S, WDl, and WO2, and in the case of multiple shooting, branches from S, WO3 to S, WO4, and the shooting method returns to single frame shooting. Jump to main processing.

In other words, multiple shooting is cleared every time.

In cases other than multiple shooting, S and WO2 are used to wind up one frame, and if the winding is not completed within a predetermined time, the process branches from S and WO6 to S and WO7, clearing the automatic shooting flag and performing the above-mentioned process. Proceed to rewind processing.

When winding is completed, the sheet number counter is counted up at S, WO8, and a new sheet number count is displayed at S, WO9, and WDIO if there is no interval.

The reason why the number of shots is not displayed in the case of interval shooting is that during interval shooting, the remaining time until release is displayed subtracted, as will be described later.

In S. Stomach Dll to WD15, the branch destination after the winding process is determined according to the set imaging method.

First, in continuous shooting, if the shutter button is kept pressed, the process jumps to ^KAF control 3 in FIG. 20 to continue the exposure sequence, and if the button is released, the process jumps to main processing.

Next, in the case of a double self, when the first image is completed, the process jumps back to the AEAF control, and when the second image is completed, the process jumps to the main process.

If it is in the interval, the process jumps to the interval control process shown in FIG. 27, and if it is not in any of the above modes, that is, in the case of single-frame photography or self-timer, it jumps to the main process.

(Interval Control Process) FIG. 27 shows the interval control process that starts from 5JD15 of the above wind process.

This process is a process of waiting while measuring the time until the second and subsequent shots are taken when the shooting method is set to interval. In cases other than intervals, the process is normally executed in a loop within the main process, but in the case of intervals, the process is executed in a loop between the EAF control process and the interval control process without going through the main process. executed.

When this process starts, the charge request flag is set at S and INl? C) IGRQ and charging request memory flag? CHGIIQ
Clear both M and M.

S, IN2. At IN3, the interval sheet number count is subtracted and it is determined whether or not this has become O. The initial value of this count is 40 sheets set in S, AF62 of the AEAF control process. When 40 images have been photographed, a charging stop process is performed at 3.184 to 1!16, the automatic photographing flag is cleared, and a mode initialization process is executed before jumping to main processing.

If the number of sheets is not 0, S, IN
Steps 7 to 1N21 are looped at a cycle of 125a+s, and the process waits until the next photographing. During this time, when any mode switch or clear switch is turned on, the mode is initialized and the main processing is resumed.

Also, during this loop, the timer subtraction is normally displayed, but when the metering switch is turned on, the number of frames is not displayed.9 Zoom tele and wide switches are set to 0! If you press I, the focal length will be displayed.

When the remaining time is less than 16 seconds, S, IN13?
CHG! IQ? CF! GRQl'l are both set to 1. This timer is used for AEAF control processing S, AF
It is set and started at 60.

S, llI20 (7) Charging control? CHGRQ is 1
When the value is 0, the battery is charged, and when the value is 0, the battery is left on the bus.

Therefore, when going around the loop of S, lN17 to rN20, -
Charging is forcibly started in the second loop, and if it is detected that sufficient charging has been performed, charging is stopped, and charging control is passed from the next loop.

When the remaining time is less than 4 seconds, it branches from S, lN19 and S, llI22. Stop charging and display the remaining time on the timer with lN23, jump to the AgAFIIJ# process in FIG.
Wait until the time is up.

[Effects] As described above, according to the strobe control device according to the first aspect, the charging voltage of the main capacitor of the strobe can be detected at a fine level with a relatively simple configuration.

Therefore, for example, exposure control can be performed in accordance with the amount of light emitted according to the charging voltage.

Further, according to the second aspect of the present invention, since a pulse is output only when the charging voltage exceeds a predetermined reference value, it is possible to reduce the possibility of misjudgment when measuring the pulse time.

According to the structure of claim 3, since the strobe is already enabled to emit light when the pulse time is measured, even if the pulse time is incorrectly measured, the strobe will not emit light when it should emit light. You can avoid such situations.

According to the configurations of claims 7 to 9, it is possible to select the charging end time and the end voltage depending on the usage state of the camera. By setting the waiting time when the camera is on standby shorter than the waiting time when the photographer is not on standby, simply turning on the main switch, sufficient voltage can be ensured and the waiting time can be shortened depending on the situation. You can choose which one to give priority to.

According to the structure of claim 10, the exposure can be corrected according to the change in the guide number according to the charging voltage, and even if the charging voltage of the main capacitor of the strobe is not sufficient, the exposure can be corrected due to a decrease in the strobe light intensity. It is possible to avoid being under.

[Brief explanation of drawings]

The drawing shows a camera equipped with a strobe control device according to the present invention. 11!1 to 11!3 show the external appearance of the camera, with FIG. 1 being a plan view, FIG. 2 being a front view, and FIG. 3 being a rear view. FIG. 4 is a block diagram of the control circuit, FIG. 5 is a strobe-related circuit diagram, FIG. 6 is a timing chart for voltage check, and FIG. 7 is a graph showing the relationship between RLS pulse time and voltage. Figures 8 to 29 show the strobe control m&! of this embodiment. 1 is a flowchart showing the functions of a camera equipped with a device,
Figure 8 is the reset process, 9.11, 12.13 [1 is the main process, Figure 10 is the loop extraction process, 141
15 shows charging control (including stop processing) processing, Fig. 15 shows charging prohibition processing, Fig. 16 shows RLS pulse time measurement processing, Fig. 17 shows timeout check processing, Fig. 18 shows charging prohibition time reduction processing, and Fig. 19 shows charging inhibition processing. Lock handling, Section 20.21.22
The figure shows AEAF control processing, Fig. 23 shows voltage/voltage check processing, Fig. 24 shows FM calculation processing, Fig. 25 shows release waiting charging processing, Fig. 26 shows wind processing, and Fig. 27 shows interval control processing. There is. Figure 1 Figure 2 Figure 3

Claims (10)

[Claims] (1) It is characterized by comprising a pulse output means for outputting a pulse with a time width corresponding to the charging voltage of a main capacitor for a strobe, and a voltage measuring means for measuring the time width of the pulse and detecting the charging voltage. Strobe control device. (2) The strobe control device according to claim 1, wherein the pulse output means outputs a pulse only when the charging voltage exceeds a predetermined reference value. (3) The strobe control device according to claim 2, wherein the reference voltage is a strobe light emission permission voltage. (4) The pulse output means has a switch means that is turned ON/OFF based on a check signal for checking the charging voltage of the main capacitor, and has a characteristic that the energization start voltage and the energization holding voltage are different, a hysteresis element to which the voltage of the main capacitor is applied, and a period during which the voltage applied to the hysteresis element drops from the energization start voltage to the energization holding voltage after the switch means is turned from ON to OFF while the hysteresis element is energized. 2. The strobe control device according to claim 1, further comprising: compensating means for compensating the energization of the hysteresis element, and wherein the compensating means outputs a pulse corresponding to a time during which the energization of the hysteresis element is compensated. (5) The strobe control device according to claim 5, wherein the hysteresis element is a neon tube. (6) The strobe control device according to claim 5, wherein the compensation means is a capacitor. (7) Voltage measuring means for detecting the charging voltage of the strobe main capacitor, charging time measuring means for measuring the elapsed time from the start of charging, and one charging end time selected from multiple charging end times depending on the usage status of the camera. A strobe control device comprising a charging time limiting means for selecting a time and for terminating charging if the charging voltage does not reach a predetermined value even after the selected charging termination time has elapsed. (8) Voltage measuring means for detecting the charging voltage of the strobe main capacitor, charging time measuring means for measuring the elapsed time from the start of charging, and one charging end voltage selected from a plurality of charging end voltages depending on the usage status of the camera. 1. A strobe control device comprising a charging voltage limiting means that selects a charging voltage and terminates charging if a set charging termination voltage is not reached even after a predetermined charging time has elapsed. (9) A strobe control device comprising the charging time limiting means according to claim 7 and the charging voltage limiting means according to claim 8. (10) A strobe control device comprising: voltage measuring means for detecting the voltage of a strobe capacitor; and exposure determining means for determining a corresponding appropriate exposure value based on the measured voltage.