JPH09105983A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wasteful power consumption caused by the execution of range-finding operation in an uncharged state in the constitution of a camera where shutter operation is inhibited when a capacitor for a stroboscope is uncharged. SOLUTION: This camera is provided with a main capacitor voltage detection means 14 starting the decision whether or not the amount of the charge accumulated in the capacitor 13 attains a specified amount according as a release button is depressed by one stem, a range-finding start control means inhibiting the measurement of a distance to a subject by a range-finding means 18 according to the decision that the amount of the charge accumulated in the capacitor 13 does not attain the specified amount and starting the measurement of the distance to the subject by the range-finding means 18 according to the decision that the amount of the charge accumulated in the capacitor 13 attains the specified amount, and an exposure start control means starting exposing operation including shutter opening/closing operation according as the measurement of the distance to the subject is completed and the release button is deprssed by two steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention comprises a capacitor,
The present invention relates to a camera capable of accumulating electric charges necessary for causing a light emitting tube to emit light in the capacitor.

[0002]

2. Description of the Related Art As a camera of this type, when the main capacitor of the flash device is not charged, even if the release button is pressed, the shutter operation in response to this is prohibited,
It is known to prevent shooting failures due to insufficient exposure.

[0003]

However, in this camera, even when the main capacitor is not charged, when the release button is pushed and pressed, the distance measuring operation is performed in response to this. As described above, the shutter operation is prohibited when the main capacitor is uncharged, so the distance measurement operation performed when the main capacitor is uncharged is useless.
In other words, it was a waste of power consumption.

An object of the present invention is to provide a camera that eliminates the above waste.

[0005]

The present invention achieves the above object by the following means. According to the invention described in claim 1, a capacitor capable of accumulating electric charges necessary for causing the arc tube to emit light, a distance measuring unit for measuring a distance to a subject, and a release button that can be pressed in two steps. When the release button is pressed in one step, a determining unit that starts determining whether or not the amount of electric charge stored in the capacitor has reached a predetermined amount, and the determining unit stores the electric charge stored in the capacitor. In response to the determination that the amount of electric charge present has not reached the predetermined amount, measurement of the distance to the subject by the distance measuring means is prohibited, and the amount of electric charge accumulated in the capacitor reaches the predetermined amount. In accordance with the determination that the distance to the object is measured by the distance measuring means, the distance measurement start control means starts measuring the distance to the object, and the release button is pressed in two steps. What is done In response, it provided the exposure start control means for starting the exposure operation including the shutter opening and closing operation in the camera.

According to the second aspect of the present invention, when the determination means determines that the amount of electric charge accumulated in the capacitor has not reached the predetermined amount,
The camera according to claim 1 is provided with a charge control device that starts accumulation of electric charge in the capacitor in response to release of the one-step depression of the release button.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (Description of FIG. 1 Block Diagram) FIG. 1 shows a first form of a block diagram of a circuit of a camera. The camera of this embodiment has a power switch and a release button in addition to the components shown in FIG. 1 (none of them are shown). It is assumed that the release button can be pressed in two stages (hereinafter, the first-stage press is half-pressed and the second-stage press is fully pressed).

When a power switch (not shown) is turned on, the central processing unit 15 (hereinafter referred to as the CPU 15) is in a half-press interrupt enable state. The half-press interrupt enable state means that when the CPU 15 presses the release button halfway,
It is in a state where half-push interrupt processing can be started. The half-press interrupt process will be described in detail in the description of FIG.
After entering the half-push interrupt enable state, the CPU 15 sets L
A (low level) SBO signal (charge start signal) is output to the charging means 12. The signal causes the charging means 12 to start charging the main capacitor 13. CPU1
After outputting the SBO signal to the charging means 12, the reference numeral 5 starts time measurement using a built-in 20-second timer. When the amount of electric charge accumulated in the main capacitor 13 reaches the first predetermined amount, the main capacitor voltage detection means 14 outputs the NL1 signal to the CPU 15. The first predetermined amount is the minimum amount of electric charge required to obtain an appropriate amount of light by strobe emission. While the charging means 12 continues to charge the main capacitor 13,
The output of the NL1 signal is continued. After that, the charging of the main capacitor 13 is further continued, and when the time measurement by the 20-second timer is completed, the CPU 15 outputs an H (high level) SBO signal (charging stop signal) to the charging means 12, and the charging means 12 is charged. Charging of the main capacitor 13 is stopped. At this time, the charge amount of the main capacitor 13 is equal to or higher than the first predetermined amount and equal to or lower than the withstand voltage.
The breakdown voltage means the amount of electric charge when there is a risk that the main capacitor 13 will be destroyed by excessive charging. Note that the charging start timing is not limited to when the power switch is turned on. Also, the charging stop timing is not limited to the completion of the time measurement of the 20-second timer. A detailed description of the charging start / stop timing will be described later.

When a release button (not shown) is half pressed, the switch S1 is turned on. When the switch S1 is turned on during charging of the main capacitor 13, the CPU 15 causes the charging means 1 to operate.
2 output H SBO signal to main capacitor 13
To stop charging. Further, the CPU 15 is the photometric device 1
The subject brightness is measured according to 6, and the photometric result is stored. After storing the photometric result, the CPU 15 outputs the SBO signal of L for a fixed time (50 ms). This operation is called monitor charging. Figure 2 for monitor charging
Will be described in detail in the description. Further, the CPU 15 determines whether or not the flash is necessary. The flash necessity determination is made based on the state of the flash mode switching switch 17 and the photometric result of the photometric device 16. Flash mode switch 1
Reference numeral 7 denotes a switch for selecting one of the automatic light emission mode, the light emission prohibition mode, and the forced light emission mode. The automatic light emission mode is a mode in which the CPU 15 automatically determines light emission / non-light emission based on the result of photometry. The light emission prohibition mode is an SBT signal (strobe trigger signal) from the CPU 15 to the ignition means 111 regardless of the result of photometry.
Is a mode in which the output of is prohibited. The forced light emission mode is a mode in which the Xe tube 112 emits light during exposure regardless of the result of photometry. The determination of whether or not the flash is necessary will be described later.

When a release button (not shown) is fully pressed, the switch S2 is turned on. When the switch S2 is turned on, it is determined whether or not the NL1 signal has been received (that is, the amount of charge accumulated in the main capacitor 13 corresponds to the first The CPU 15 controls the subsequent camera operation based on whether or not the predetermined amount has been reached. Subsequent camera operations include measuring the distance from the camera to the subject by the distance measuring unit 18, driving the taking lens 110 by the focusing unit 19 based on the distance measuring result, and the SBT transmitted from the CPU 15. Ignition means 1 for signal (strobe trigger signal)
11, the ignition means 111 causes the Xe tube 112 to emit light.

(Explanation of FIG. 2 Circuit Diagram) FIG. 2 is a circuit diagram including the charging means 12, the main capacitor 13, the main capacitor voltage detecting means 14, the ignition means 111 and the Xe tube 112 of FIG. When the battery is loaded, terminal VB-terminal G
A voltage is applied between ND. When the power switch is turned on, the SBO signal of L is input from the CPU 15 to the SBO terminal (terminal that receives the SBO signal), and the transistor Q1
Is turned on. When the transistor Q1 is turned on, the transistor Q3 is turned on, and the booster circuit including a known blocking oscillator operates. The blocking oscillator circuit of the present embodiment includes a transformer T, a transistor Q4, a capacitor C1 and a register R1. The output voltage of the booster circuit is supplied to the main capacitor C4 (corresponding to the main capacitor 13 in FIG. 1) through the diodes D3 and D4, and the electric charges are accumulated in the main capacitor C4. Further, when the power switch is turned on and the CPU 15 transmits the L SBO signal to the SBO terminal,
The 20-second timer has begun timing.

When the amount of charge accumulated in the main capacitor C4 reaches the first predetermined amount, a part of the current flowing from the diode D3 to the diode D4 passes through the resistor R2 and lights the neon tube Ne. The neon tube Ne is an element that turns on when a voltage of a predetermined level or higher is applied.
When the neon tube Ne lights up, the CP of FIG.
The NL1 signal is transmitted to U15. The first predetermined amount is determined by the characteristics of the neon tube Ne.

After that, when the time measurement by the 20-second timer is completed, the CPU 15 outputs the H SBO signal to the terminal SBO. When the H SBO signal is input to the terminal SBO,
The transistor Q1 turns off. When the transistor Q1 is turned off, the transistor Q3 is turned off and the boosting operation is stopped. That is, the charging of the main capacitor C4 is stopped. After the charging of the main capacitor C4 is stopped, the charge accumulated in the main capacitor C4 does not flow out from the terminal NL1 due to the action of the diode D4.

During charging of the main capacitor C4, the capacitor C2 is charged by the current passing through the resistor R4. When an SBT signal (strobe trigger signal) is input from the CPU 15 to the SBT terminal, the thyristor SCR turns on. When the thyristor SCR is turned on, the electric charge of the capacitor C2 is discharged. The voltage boosted by the transformer TC ignites the xenon tube Xe. Xenon tube Xe
Emits light due to the electric charge accumulated in the main capacitor C4.

By the way, when the charging of the main capacitor C4 is stopped, the output of the NL1 signal from the terminal NL1 is also stopped. The CPU 15 recognizes whether or not the amount of electric charge accumulated in the main capacitor C4 reaches the first predetermined amount in the state where the charging is stopped, so that the SBO of L to the terminal SBO is kept for a fixed time (50 ms). Output a signal. This operation is called monitor charging. Less than,
The monitor charging will be described.

The CPU 15 sends the L SBO signal to the terminal SBO.
The blocking oscillator described above is activated.
The output of the blocking oscillator is output from the diode D3. The diode D4 is not energized unless the voltage between the diodes D3 and D4 exceeds the voltage between the electrodes of the main capacitor C4. The state where the voltage between the electrodes of the capacitor C4 has not reached the first predetermined value (main capacitor C4
4), the voltage between the diodes D3 and D4 is the first
Even if the predetermined value is not exceeded, the diode D4 is energized. At this time, since the voltage between the diodes D3 and D4 does not exceed the first predetermined value, the neon tube Ne does not light and the NL1 signal is not output. When the voltage between the electrodes of the main capacitor C4 reaches the first predetermined value when the monitor charging is performed (if the amount of charge accumulated in the main capacitor C4 reaches the first predetermined amount), When the voltage between the diodes D3 and D4 exceeds the first predetermined value, the diode D4 is energized. At this time, the diode D3-D
Since the voltage between 4 is higher than the first predetermined value, the neon tube Ne is turned on and the NL1 signal is output. By this monitor charging operation, the CPU 15 can recognize whether or not the amount of charge accumulated in the main capacitor C4 has reached a predetermined amount.

(FIG. 3 flowchart of main routine)
FIG. 3 shows a flowchart of a main routine started by turning on the power switch. In S100, the power switch is turned on. The taking lens 110 of the present embodiment shown in FIG. 1 is supported by a lens barrel that can be retracted, and when used, it can be extended from the retracted position and zoomed between a wide position and a tele position. The retracted position is a state in which the lens barrel is housed in the camera body. When the lens barrel is in the retracted position, the camera cannot take a picture. The wide position is a state in which the zoom lens 110 capable of zooming has the shortest focal length. The tele position is a state in which the taking lens 110 has the longest focal length.

When the power switch is turned on in S100, the lens barrel supporting the taking lens 110 is driven from the retracted position to the wide position in S101.
After that, the CPU 15 enters the half-press interrupt enable state.
The half-push interruption enabled state means that the release button is half-pushed and the switch S1 of FIG. 1 is turned on.
Is in a recognizable state. Alternatively, when it is recognized that the switch S1 is turned on, the CPU 15 is in a state of starting the half-press interrupt process of FIG. 4 described later. CP
The half-press interrupt enable state of U15 continues until the power switch is turned off and the half-press interrupt disable state is set. CPU15 in half-press interrupt enabled state
Starts strobe charging (S103). That is, the SB of L with respect to the terminal SBO of the charging means 12 (see FIG. 2).
The output of the O signal is started. While the L SBO signal is being input to the terminal SBO, the blocking oscillator in FIG. 2 operates to charge the main capacitor (13 in FIG. 1, C4 in FIG. 2). At this time, the CPU 15 also starts the time measurement by the built-in 20-second timer (S104).

After that, the CPU 15 judges the power switch,
That is, the on / off state of the power switch is determined (S10
5). If the power switch is off, the main routine proceeds to S109. If the power switch is turned on, the CPU 15 determines whether or not the timer is up, that is, the time measurement by the 20-second timer is completed (S10).
6). If the timing is not completed, the main routine is S
Return to 105. If the time measurement is completed, the CPU 15 stops strobe charging (S107). That is, CPU1
Reference numeral 5 inverts the SBO signal input to the terminal SBO from L to H. By reversing the SBO signal to H,
The blocking oscillator circuit of FIG. 2 is stopped, and charging of the main capacitor is stopped. At this point, the main capacitor has accumulated a charge amount equal to or higher than the first predetermined amount and equal to or lower than the breakdown voltage of the main capacitor. That is, charging of the main capacitor is completed. In addition, at the timing when the charge amount of the main capacitor during charging reaches the first predetermined amount, the NL1 signal is output from the terminal NL1 as described above.

After this, the main routine enters a state in which the power switch determination is repeated (S108). That is, the power supply switch is in a waiting state. S105 or S1
When the power switch is turned off at 08, the main capacitor is in the half-push interrupt disabled state (S109).
In the interrupt disabled state, even if the switch S1 of FIG. 1 is turned on by pressing the release button halfway, the CPU 15
Does not recognize that the switch S1 is on. Alternatively, even if the switch S1 is recognized to be on, the halfway press interrupt process of FIG. 4 is not started. After the CPU 15 is in the half-press interrupt disabled state, the lens barrel supporting the taking lens 110 is driven to the retracted position (S110), and the main routine ends.

(Flowchart of Half-press Interrupt Processing) FIG. 4 shows a flowchart of half-press interrupt processing. When the release button is pressed halfway and the switch S1 of FIG. 1 is turned on while the CPU 15 is in the half-press interrupt enable state, the CPU 15 interrupts the main routine of FIG.
The flowchart of the halfway press interrupt process of FIG. 4 is started (S201). The CPU 15 stops strobe charging. That is, the SBO signal of H is output to the SBO terminal of FIG. 2 (S202). The blocking oscillator circuit of FIG. 2 which has received the SBO signal of H from the SBO terminal stops its operation,
Charging of the main capacitor is stopped. CPU15
Outputs an H SBO signal and then performs a battery check (S203). That is, check the battery consumption. When the battery is exhausted, the result of the battery check is “NG”. In this case, the halfway press interrupt process is stopped (S204). When the battery is exhausted, not only the half-press interrupt process is stopped, but also the main routine may be ended. S203
If the battery is not exhausted in, the result of the battery check is “OK”. In this case, the CPU 15 performs photometric processing (S205). That is, the CPU 15 is
The subject brightness is measured by the photometric device 16 and the photometric result is stored. After storing the photometric result, CPU15
Starts monitor charging (S206) and makes NL1 determination (S207). That is, it is determined whether the amount of charge accumulated in the main capacitor has reached the first predetermined value.

First, the processing when the amount of electric charge accumulated in the main capacitor has not reached the first predetermined amount will be described. When the amount of charge accumulated in the main capacitor has not reached the first predetermined value, the result of the NL1 determination is “charge incomplete”. In this case, the viewfinder LED blinks after the monitor charging is stopped in S208 (S209). By blinking the fianda LED, a person who operates the camera can recognize that charging to the main capacitor is not completed. After this, the CPU 15 sets S1
A determination is made (S210). That is, it is determined whether or not the half-press of the release button has been released. If the release button has not been half pressed, the CPU 15 returns to S1 of S210.
Repeat the judgment. That is, in S210, the process waits for release of the half-press release. If the release button is not half pressed in S210, the viewfinder L
The ED is turned off (S220). Then, the CPU 15 starts strobe charging (S228), starts counting by the 20-second timer (S229), and stops strobe charging when the counting by the 20-second timer is completed (S23).
0). When the strobe charging is stopped, the half-press interrupt process ends, and the CPU 15 restarts the main routine from the point, that is, between S107 and S108 of the main routine (S231).

During the processing of S228 to S230, CP
U15 is in the half-push interrupt enable state. That is, S
If the release button is pressed halfway during the processing of 228 to S230, the processing returns to S201. In addition, S207
The processing when the amount of electric charge accumulated in the main capacitor has reached the first predetermined amount will be described.
When the amount of charge stored in the main capacitor has reached the first predetermined value, the result of the NL1 determination is “charge completed”. In this case, the distance measurement process is performed after the monitor charging is stopped in S211 (S212). The distance measuring process is a process in which the CPU 15 measures the distance to the subject using the distance measuring means 16 shown in FIG.

After measuring the distance to the subject by the distance measuring process, it may be determined whether or not the distance to the subject is shorter than the reference distance. The reference distance here is
Short-distance side photographing limit distance, that is, the photographing lens 11 of FIG.
0 corresponds to the closest focusing distance. When the distance to the subject is shorter than the reference distance, the taking lens 110 cannot focus on the subject.

When it is determined that the distance to the subject is shorter than the reference distance in the distance measuring process of S212, the process of FIG. 4 proceeds from S212 to S210. That is, if it is determined that the distance to the subject is shorter than the reference distance,
As in the case where the amount of charge accumulated in the main capacitor has not reached the first predetermined amount, the state of waiting for the release half-release release is entered. Further, in this case, the LED does not light at all. The person who operates the camera can recognize that the distance to the subject is shorter than the closest distance by not turning on the LED. The processing from S210 onward is the same as the processing from S210 onward when "the amount of charge accumulated in the main capacitor does not reach the first predetermined amount".

When the distance measuring process is completed, the CPU 15 determines whether or not the flash is necessary (S213). Strobe necessity determination means that when the sector (shutter) is opened and the photographic film is exposed, the Xe tube (112 in FIG. 1, X in FIG. 2) is used.
This is a process of determining whether or not the light emission of e) is necessary.
If the flash mode switch 17 in FIG. 1 is set to the automatic flash mode and the photometric value stored in S205 is lower than the reference value, or if the flash mode switch 17 is set to the forced flash mode, the flash The result of the necessity determination is "necessary". In this case, the flash emission flag is set to "1" (S214), and the finder LED is turned on (S215).

If the flash mode changeover switch 17 is set to the automatic light emission mode and the photometric value stored in S205 is higher than the reference value, or if the flash mode changeover switch is set to the light emission prohibition mode, in S213. The result of the strobe necessity determination is “No”. In this case, the flash emission flag is set to "0" (S21
6), the finder LED is momentarily turned on (S217).

After the processing of S215 or S217 is completed, the CPU 15 makes an S2 determination (S218). The S2 determination is a process of determining whether or not the switch S2 in FIG. 1 has been turned on, that is, whether or not the release button has been fully pressed. If the release button is not fully pressed, CPU1
5 performs S1 determination (S219). If the release button is not pressed halfway, after performing the processing of S220, S
The CPU 15 performs the processes of steps 228 to S230, and the CPU 15 points the main routine, that is, S10 of the main routine.
It restarts from between 7 and S108 (S231).

If the half-press of the release button has not been released in S219, the process returns to S218. S218
If the release button is fully pressed in step S221, the viewfinder LED is turned off in step S221, and steps S222 to S22 are performed.
At 7, a process is performed to expose the film.
First, in S222, the lens is extended. That is, based on the result of the distance measurement processing in S212, the focusing means 1
9 (FIG. 1) is used to drive the taking lens 110 (FIG. 1). The sector (shutter) is opened and closed during S223 to S226. While the sector is open, the strobe light emission flag determination is performed (S224). If the strobe light emission flag is "1", the Xe tube 112 emits light (while the sector is open) in S225. When the strobe light emission flag = “0”, the Xe tube 112 does not emit light and the sector is closed. After the opening and closing of the sector is completed, the lens returning process is performed (S
227). Shooting lens 1 extended in S222
10 is returned to its original position. Although not shown in FIG. 4, the process for exposing the film also includes the process of winding the taken film by one frame after the taking lens 110 returns to the original position.

When the processing for exposing the film is completed in S227, the charging processing in S228 to S230 is performed, and the halfway press interrupt processing is ended (restarted from the point where the main routine is restarted). (Explanation of FIG. 5 Block Diagram) FIG. 5 shows a second form of a block diagram of a camera circuit. The block diagram of FIG. 5 differs from the block diagram of FIG. 1 in that the main capacitor voltage detecting means 1
Only at the point where 4'outputs the NL2 signal.

When a power switch (not shown) is turned on, C
The PU 15 outputs the SBO signal of L to the charging means 12.
The signal starts charging the main capacitor 13. When the amount of charge accumulated in the main capacitor reaches the first predetermined amount, the main capacitor voltage detecting means 1
The NL1 signal is sent from 4 ′ to the CPU 15. afterwards,
Further, the main capacitor 13 is continuously charged, and when the amount of charges accumulated in the main capacitor 13 reaches the second predetermined amount, the main capacitor voltage detection means 14 'sends the NL2 signal to the CPU 15. The second predetermined amount is an electric charge amount that is equal to or larger than the first predetermined amount and equal to or lower than the breakdown voltage of the main capacitor 13. When the CPU 15 receives the NL2 signal, it outputs an H SBO signal to the charging means 12 to stop the charging of the main capacitor 13.

(Explanation of Circuit Diagram in FIG. 6) FIG. 6 is a circuit diagram including the charging means 12, the main capacitor 13, the main capacitor voltage detecting means 14 ', the ignition means 111 and the Xe tube 112 in FIG. The circuit diagram of FIG. 6 is similar to the circuit diagram of FIG.
A circuit configuration for outputting two signals is added. Therefore, a circuit configuration for outputting the NL2 signal will be described.

When the amount of charge stored in the main capacitor C4 reaches the second predetermined amount, the Zener diode ZD
1 turns on. The Zener diode ZD1 is an element that is turned on (energized) when an electric charge of a predetermined level or higher is applied. The current passing through the Zener diode ZD1 passes through the resistor R3 and is output from the terminal NL2. Terminal N
The current output from L2 is the CPU1 as the NL2 signal.
5 is input. The second predetermined amount is determined by the characteristics of the Zener diode ZD1. Upon receiving the NL2 signal, the CPU 15 outputs the H SBO signal to the terminal SBO. That is, in the circuit diagram of FIG. 2, the same operation as when the time measurement by the 20-second timer is completed is performed.

The circuit of FIG. 6 is also provided with a configuration for forcibly stopping the charging operation to protect the circuit when the CPU 15 cannot recognize the NL2 signal due to a failure or the like. As a result of continuing the charging, when the charge amount accumulated in the main capacitor reaches the third predetermined amount, the current output from the Zener diode ZD1 is the diode D2.
To turn on the transistor Q2. The third predetermined amount is a charge amount that is equal to or larger than the second predetermined amount described above and equal to or lower than the withstand voltage of the main capacitor C4. When the transistor Q2 is turned on, the transistor Q4 is turned off and the boosting operation is stopped. That is, even if the SBO signal remains the L signal due to a failure or the like, the amount of charge accumulated in the main capacitor C4 does not exceed the withstand voltage.

(Explanation of FIGS. 7 and 8) FIG. 7 is a flowchart of the main routine (control started by turning on the power switch) of the camera of FIGS. 5 and 6. FIG.
FIG. 8 is a flowchart of a half-press interrupt process started by half-pressing the release button. The flowchart of FIG. 7 differs from the flowchart of FIG. 3 only in S106 ′. 8 is different from FIG. 4 in S229 ′.
Only. Then, S106 'and S229' are the same processing. Here, only the processing of S106 ′ (S229 ′) will be described, and it is assumed that FIGS. 7 and 8 have been described.

The processing of S106 '(S229') is NL
2 judgment. The NL2 determination is a process in which the CPU 15 determines whether or not the NL2 signal is output from the main capacitor voltage detection means 14 ′ of the charging means. NL
When two signals are output, the result of the NL2 determination is “charge completed”. At this time, in the main routine of FIG.
When L2 determination = “charge not completed”, the process returns to S105. In the half-press interrupt process of FIG. 8, NL2 determination =
If "charging is not completed", the process repeats S209 '.

In the processing of FIGS. 4 and 8,
The photometric processing is performed in S205. That is, the photometric processing is performed before the battery check (S203) is completed and the monitor charging is started (S206).
However, the timing of performing the photometric processing is not limited to the timing shown in FIGS. 4 and 8. For example, the photometry processing may be performed after the distance measurement processing (S212). With this configuration, the photometric process is not performed unless the NL1 determination in S207 = "charge completed".

In the cameras of the two embodiments described above, the operation for exposing the photographic film is prohibited when the amount of charge accumulated in the main capacitor does not reach the predetermined amount. Further, regardless of whether or not the photographic film has been exposed, the main capacitor is always charged when the half-press of the release button is released.

[0039]

According to the camera of the first aspect of the present invention, when it is determined that the amount of electric charge accumulated in the capacitor has not reached the predetermined amount, the distance measuring means is prohibited from measuring the distance to the object. . That is, the execution of the distance measuring operation is permitted only in the situation where the proper exposure is obtained. Therefore, the distance measurement operation is not performed and unnecessary power is not consumed even in the situation where proper exposure cannot be obtained.

Further, the camera according to claim 1 of the present application starts the exposure operation including the shutter opening / closing operation in response to the completion of the distance measuring operation and the depression of the release button in two steps. That is, if the shutter opportunity is waited for after the distance measuring operation is completed, there is almost no deviation between the timing of the release operation and the timing of the exposure operation. In other words, never miss a photo opportunity.

According to the camera of claim 2 of the present application, when it is determined that the amount of charge accumulated in the capacitor has not reached the predetermined amount, the release button is released from one-step depression in response to the release. The charge starts to accumulate in the capacitor. That is, when the charging is not completed, the charging is automatically started, which is convenient.

[Brief description of the drawings]

FIG. 1 is a block diagram of a circuit of a camera according to the present invention.

2 is a diagram showing a charging unit 12, a main capacitor 13,
It is a circuit diagram including a comparator 14, an ignition means 111, and a Xe tube 112.

FIG. 3 is a flowchart of a main routine started by turning on a power switch.

FIG. 4 is a flowchart of a half-press interruption process started by half-pressing a release button.

FIG. 5 is a block diagram of a circuit of a camera according to the present invention.

FIG. 6 shows a charging means 12, a main capacitor 13,
It is a circuit diagram including a comparator 14 ', an ignition means 111, and a Xe tube 112.

FIG. 7 is a flowchart of a main routine started by turning on a power switch.

FIG. 8 is a flowchart of a half-press interrupt process started by half-pressing a release button.

[Explanation of symbols]

11 ... Battery, 12 ... Charging means, 13, C4 ... Main capacitor, 14 ... Comparator, 15 ... Central processing unit (CPU), 16 ... Photometric means, 17 ... Flash mode switching switch, 18 ... Distance measuring means,

Claims (2)

[Claims] Claim: What is claimed is: 1. A condenser capable of accumulating a charge necessary for causing an arc tube to emit light, a distance measuring means for measuring a distance to a subject, a release button that can be pressed in two steps, and one step of the release button. A determination unit that starts determination of whether or not the amount of charge accumulated in the capacitor has reached a predetermined amount in response to the pressing, and the amount of charge accumulated in the capacitor by the determination unit is Depending on the judgment that the predetermined amount has not been reached,
Prohibiting measurement of the distance to the subject by the distance measuring means,
Distance measurement start control means for starting measurement of the distance to the object by the distance measurement means in response to the determination that the amount of charge accumulated in the capacitor has reached the predetermined amount, and A camera having an exposure start control means for starting an exposure operation including a shutter opening / closing operation in response to completion of measurement of a distance and pressing of the release button in two steps. 2. When the determination means determines that the amount of electric charge accumulated in the capacitor has not reached the predetermined amount, the one-step depression of the release button is released. The camera according to claim 1, further comprising a charge control device that starts to accumulate electric charge in the capacitor.