JPH08122874A - Film feeding device for camera - Google Patents

Abstract

PURPOSE: To simplify a converting circuit for sensor output signal by converting the output current of a detecting means into voltage, comparing this voltage with a threshold voltage, and controlling the feed of a film on the basis of the result. CONSTITUTION: Sensors PS1 and PS2 output currents according to the change of incident light quantity caused by a difference in light transmittance or light reflecting ratio between a perforation and a film. These output currents are converted into voltage by a load resistor R, and sent to a comparator CP1. A D/A converter converts the digital value of a threshold voltage sent from an arithmetic control device CPU into analog value, and transmits it to the comparator CP1. The comparator CP1 compares the perforation detected voltage with the threshold voltage, outputs a perforation detection signal to the arithmetic control device CPU when the detected voltage exceeds the threshold voltage, and outputs a film detection signal when the detected voltage is lower than the threshold voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film feeding device for a camera.

[0002]

2. Description of the Related Art A camera is known which detects film perforation to control film feeding and magnetic recording on the film (see, for example, Japanese Patent Laid-Open No. 4-328536). In this type of camera, for example, a film as shown in FIG. 2 is used. On one side of this film, two perforations PX and PY are provided at unequal intervals for each frame. In order to detect such a perforation of the film, two sensors are arranged in front of and behind the film feeding direction, and the magnetic recording frequency and the magnetic recording are based on the detection result of the perforation by the first sensor. The start timing is determined, and the magnetic recording end timing and the film feeding stop timing are determined based on the detection result of the perforation by the second sensor.

However, in the above-described conventional film feeding device for a camera, since the film feeding control is performed by using the two perforation detecting sensors, the output signal of each sensor is used as the film feeding control. There is a problem that two signal conversion circuits for converting the signals into a signal that can be read by the microcomputer for performing the above are required, installation space for these conversion circuits is required, and power consumption and cost increase.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a film feeding device for a camera, in which a conversion circuit for converting output signals of a plurality of perforation detecting sensors is simplified.

[0005]

In order to achieve the above object, the invention of claim 1 feeds a film, a plurality of detecting means for detecting a predetermined position on the film, and a plurality of these detecting means. A signal conversion unit that is provided in common to a plurality of detection units and that converts the output current of each of the detection units into a voltage, a comparison unit that compares the output voltage of this signal conversion unit with a threshold voltage, and this comparison unit. Control means for controlling the feeding of the film by the feeding means on the basis of the result of the comparison. 3. The film detecting device of the camera film feeding device according to claim 2, wherein the detecting means is an optical sensor that outputs a current proportional to the amount of incident light, and the signal converting means is connected to an output terminal of the optical sensor and outputs from the terminal. It is a resistor that generates a voltage proportional to the applied current. The film feeding device for a camera according to claim 3 comprises power supply means for separately supplying power to each of the detection means only during a period in which each of the detection means needs to be operated. A film feeding device for a camera according to a fourth aspect of the present invention comprises a threshold voltage supply means for supplying a threshold voltage corresponding to each of the detection means to the comparison means. According to a fifth aspect of the present invention, the film of the film feeding device is a film in which a plurality of perforations are provided at unequal intervals and at the same location of each photographing frame, and the detection means detects the perforations.

[0006]

The output current of each detecting means is converted into a voltage by the signal converting means provided commonly to the plurality of detecting means, and this voltage is compared with the threshold voltage. Then, the film feeding is controlled based on the comparison result. It should be noted that, for each detection means, power is separately supplied to each detection means only during a period in which each detection means needs to be operated, and a threshold voltage corresponding to each detection means is supplied to the comparison means. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a functional block diagram showing the structure of a camera equipped with a film feeding apparatus according to an embodiment. SW1 is a power switch of the camera, SW2 is a switch that is turned on when a release button (not shown) is half-pressed, and SW3 is a switch that is turned on when the release button is fully pressed.
Further, SMg is a magnet for opening and closing the shutter. CON is a control circuit for the camera, which performs photometry, distance measurement, mirror control, aperture control, shutter opening / closing magnet control, etc. in response to a command from an arithmetic and control unit CPU described later. The photometric information and the distance measuring information are sent to the arithmetic and control unit CPU. The EEPROM is an electrically erasable non-volatile memory in which various data such as a threshold voltage for a comparator and an adjustment value of the camera are recorded via an IN terminal when the camera is manufactured. M
D is a drive circuit for the film feeding motor M, which drives the motor M to wind and rewind the film.

PS1 and PS2 are optical sensors for detecting the perforation of the film,
A current is output according to a change in the amount of incident light caused by a difference in light transmittance or light reflectance between the perforation and the film. In this embodiment, an example using a light transmission type sensor will be described. This output current is converted into a voltage by the load resistor R and sent to the comparator CP1. Hereinafter, the voltage across the load resistor R will be referred to as a perforation detection voltage. The load resistor R is the sensor PS1 and P.
Commonly provided for S2. The D / A converter converts the digital value of the threshold voltage sent from the arithmetic and control unit CPU into an analog value and sends it to the comparator CP1. The comparator CP1 compares the perforation detection voltage with the threshold voltage, and when the detection voltage exceeds the threshold voltage, the arithmetic control unit CP1.
A perforation detection signal is output to U, and a film detection signal is output when the detection voltage becomes lower than the threshold voltage.

The arithmetic and control unit CPU is composed of a microcomputer and peripheral parts such as a ROM, a RAM and a timer, and performs various sequence controls of the camera and various arithmetic operations. The arithmetic and control unit CPU receives the first threshold voltage for the sensor PS1 and the sensor P from the EEPROM.
The second threshold voltage for S2 is input, and one of the threshold voltages is output to the D / A converter as needed. The arithmetic and control unit CPU also supplies power to the sensor PS1 via the line L7 and power to the sensor PS2 via the line L8. Power is not supplied to the sensors PS1 and PS2 at the same time, but power is supplied separately for each period during which each sensor needs to be operated. The arithmetic and control unit CPU further controls the drive circuit MD to control the film feeding.

FIG. 2 is a diagram showing the positional relationship between the film used in one embodiment and the sensors PS1 and PS2, in which an arbitrary photographing frame Fn (n = 1, 2, ...) Has a predetermined photographing position. , That is, a state in which it is set at a position facing the aperture. This camera is a so-called normal wind type camera that shoots while film is being wound frame by frame. There is a take-up spool of a camera (not shown) on the right side of the figure, and a film cartridge (not shown) on the left side of the figure. There is. Therefore, the right direction in the figure is the winding direction, and the left direction is the rewinding direction. Also,
The leader of the film is on the right side of the figure. Two perforations are provided on one side of the film at the same location on each shooting frame. In the following, an arbitrary shooting frame Fn is provided.
The perforation on the cartridge side (left side in the drawing) is called PX, and the perforation on the reader side (right side in the drawing) is called PY. The front end of the perforation PX in the film winding direction is XF, the rear end is XR, and the front end of the perforation PY in the film winding direction is Y.
F and the rear end are called YR. Also, the black circle in the figure is the sensor P.
The installation position of S1 and PS2, that is, the detection position is shown.

3 to 8 are flow charts showing a control program of the arithmetic and control unit CPU, and FIG. 9 is a view for explaining the film feeding operation of one embodiment. The operation of the embodiment will be described with reference to these drawings. When the switch SW1 is turned on and the power of the camera is turned on, the arithmetic and control unit C
The PU starts executing this control program. In step S1, system initialization such as memory reset is performed by system reset. Continuing step S
At 2, the various adjustment data of the camera including the first threshold voltage for PS1 and the second threshold voltage for PS2 are read from the EEPROM and set. In step S3, it is determined whether or not the release button is half-pushed by the switch SW2. When the release button is half-pushed, the process proceeds to step S4, and the control circuit CON is instructed to perform photometry and distance measurement via the line L3. In step S5, it is determined whether or not the release button has been fully pressed by the switch SW3. If the release button is not fully pressed, the process proceeds to step S5A, and it is determined whether or not the release button is still half pressed by the switch SW2. If the release button is still half-pressed, the process returns to step S5 to wait for shutter release, and if the half-press of the release button is released, the process returns to step S3. On the other hand, when the release button is fully pressed and the shutter is released, the process proceeds to step S6, and the control circuit CON is instructed to perform exposure.

In step S7, the first threshold voltage for PS1 is output to the D / A converter through the line L5, and the first threshold voltage is set in the comparator CP1. Next, in step S8, the line L6
A drive circuit MD is instructed to drive the motor M to start film winding. FIG. 9A shows a state where the photographing frame Fn is set to a predetermined photographing position and the exposure is completed. From this state, one frame feed for setting the next unexposed frame Fn + 1 to the predetermined photographing position, that is, The normal wind type camera starts winding one frame. In step S9 after starting film winding, power is supplied to the sensor PS1 to start the perforation detection operation, and in step S10, the sensor PS1 is detected.
It is determined whether or not the perforation detection voltage by exceeds the first threshold voltage and the perforation detection signal is output from the comparator CP1.

As shown in FIG. 9B, when the front end XF of the perforation PX of the photographing frame Fn reaches the detection position of the sensor PS1, the amount of light incident on the sensor PS1 rapidly increases and the output current increases. The perforation detection voltage rises. Then, when the perforation detection voltage exceeds the first threshold voltage, the perforation detection signal is output from the comparator CP1. That is, when the front end XF of the perforation PX of the photographing frame Fn passes the detection position of the sensor PS1, the perforation detection signal is output.

When the sensor PS1 detects the front end XF of the perforation PX of the photographing frame Fn, step S1
Proceed to 1 to start timekeeping with the built-in timer. Supply of power to the sensor PS1 is stopped in step S12, and power is supplied to the sensor PS2 in subsequent step S13 to start the perforation detection operation. Further, in step S14, the second threshold voltage for PS2 is output to the D / A converter, and the second threshold voltage is output to the comparator CP1.
Set the threshold voltage. In step S15, the perforation detection voltage detected by the sensor PS2 exceeds the second threshold voltage, and the comparator C
It is determined whether or not the perforation detection signal is output from P1.

As shown in FIG. 9 (c), when the front end XF of the perforation PX of the photographing frame Fn reaches the detection position of the sensor PS2, the amount of light incident on the sensor PS2 sharply increases and the output current increases. The perforation detection voltage rises. When the perforation detection voltage exceeds the second threshold voltage, the perforation detection signal is output from the comparator CP1. That is, when the front end XF of the perforation PX of the photographing frame Fn passes the detection position of the sensor PS2, the perforation detection signal is output.

When the sensor PS2 detects the front end XF of the perforation PX of the photographing frame Fn, step S
16, the time from when the front end XF of the perforation PX of the shooting frame Fn passes the detection position of the sensor PS1 to when it passes the detection position of the sensor PS2 is read from the timer, and the feeding distance and feeding time in that period are read. The film winding speed Vo1 is calculated based on The feeding distance in the above period is the distance that the film moves from the state shown in FIG. 9 (b) to the state shown in FIG. 9 (c).
It is equal to the distance between the sensors PS1 and PS2.

In step S17, the calculated winding speed V
It is determined whether or not o1 is equal to or higher than a predetermined speed V1, and Vo1 is V
If it is 1 or more, it is determined that the winding is performed at high speed, and the process proceeds to step S19 to control the drive circuit MD to control the motor M.
Is driven at a duty of 50%. On the other hand, Vo1 is V1
If it is smaller than the above, the process proceeds to step S18, and the winding speed V
It is determined whether o1 is equal to or higher than the predetermined speed V2. here,
V2 <V1. If Vo1 is equal to or higher than V2, it is determined that the medium is wound at a medium speed, and the process proceeds to step S20 to control the drive circuit MD to drive the motor M with a duty of 75%. When the winding speed Vo1 is lower than the predetermined speed V2, it is determined that the winding speed is low, and the step S2 is performed.
In step 1, the drive circuit MD is controlled to drive the motor M without duty, that is, with 100% duty.

As described above, in the state shown in FIG. 9A, the film is started to be wound by one frame, and the front end XF of the perforation PX of the photographing frame Fn is detected by the sensor PS1 as shown in FIG. 9B. After passing through
As shown in (c), the feeding time until passing the detection position of the sensor PS2 is measured. Then, the feeding speed is calculated from the feeding time and feeding distance, and the duty of the motor during deceleration is set according to the feeding speed. Figure 9
At the time when the front end XF of the perforation PX of the photographing frame Fn reaches the detection position of the sensor PS1 after starting to wind one frame of the film in the state shown in (a), as shown in FIG. It is considered that the feeding speed is constant and sufficiently stable, and the influence of mechanical rattling at the start of winding described above is eliminated, so that an accurate film feeding speed can be measured. Since the drive duty of the motor M is determined according to the accurately measured feeding speed, the film can be accurately decelerated toward the target stop position regardless of the speed at which the film is wound. . The feeding time from when the front end of the perforation PX of the photographing frame Fn passes the detection position of the sensor PS1 to when it passes the detection position of the sensor PS2 is measured, and the duty of the motor during deceleration according to the measured time is measured. May be set.

In step S22, the sensor PS2
The maximum time for which the perforation PX of the photographing frame Fn passes the detection position of is set as the escape time in the timer, and it is started. If the perforation PX does not pass the detection position of the sensor PS2 even after the elapse of this escape time, it is determined that the film has stopped halfway or the film feeding speed has drastically decreased, which will be described later. Perform backup processing. In step S23, it is determined whether or not the perforation detection voltage by the sensor PS2 is lower than the second threshold voltage and the film detection signal is output from the comparator CP1.

When the rear end XR of the perforation PX of the photographing frame Fn passes the detection position of the sensor PS2, the amount of light incident on the sensor PS2 sharply decreases, the output current decreases, and the perforation detection voltage decreases. Then, when the perforation detection voltage becomes lower than the second threshold voltage, the film detection signal is output from the comparator CP1. That is, the sensor P
The detection position of S2 is set to the perforation PX of the shooting frame Fn.
When the trailing edge XR passes, a film detection signal is output. When the film detection signal is output, the process proceeds to step S25, where the time from the front end XF of the perforation PX of the photographing frame Fn passing to the rear end XR of the perforation PX and the distance of the perforation PX are detected. The hoisting speed Vo2 is obtained based on this.

In step S26, the perforation P
It is determined whether or not the passing speed Vo2 of X is equal to or higher than a predetermined speed V3, and if Vo2 is V3 or higher, it is determined that the perforation passing speed is high, and the process proceeds to step S28. Drive in%. On the other hand, if the perforation passage speed Vo2 is smaller than the predetermined speed V3, the process proceeds to step S27, and it is determined whether the passage speed Vo2 is equal to or higher than the predetermined speed V4. Here, V4 <V3. The passing speed Vo2 is the predetermined speed V
If it is 4 or more, it is determined that the perforation passage speed is medium speed, and the process proceeds to step S29, and the drive circuit MD drives the motor M with a duty of 75%. In addition,
When the passing speed Vo2 is smaller than the predetermined speed V4, it is determined that the perforation passing speed is low and the step S30 is performed.
Then, the drive circuit MD is controlled to drive the motor M with no duty, that is, with a duty of 100%.

On the other hand, in step S23, the comparator C
When the film detection signal is not output from P1, the process proceeds to step S24, and it is determined whether or not the timer having set the escape time has timed out and the escape time has ended. If the escape time has not ended, step S
Return to 23, and even if the escape time has passed, the sensor PS
When the perforation PX of the photographing frame Fn does not pass the detection position of 2, whether the film has stopped midway,
Alternatively, it is determined that the film feeding speed is drastically reduced, and the process proceeds to step S30 to control the drive circuit MD so that the motor M has no duty, that is, the duty 100.
Drive in%.

As described above, since the perforation passage time is measured after the film deceleration is started, the perforation passage speed is calculated, and the duty of the decelerating motor is reset according to the passage speed. It is possible to correct the deceleration accurately with respect to the target stop position, no matter what speed the film is decelerated. Also, the maximum time for the perforation to pass is set as the escape time, and if the perforation does not pass even after the escape time has elapsed, the brake is released and the motor is driven at 100% duty, so the film is It has stopped,
The film feeding speed does not suddenly decrease, and the reliability of the film feeding can be improved.

In step S31, the sensor PS2
The maximum time from the passage of the rear end XR of the perforation PX of the photographing frame Fn to the passage of the front end YF of the perforation PY of the next photographing frame Fn + 1 is set as the escape time in the timer and the start is started. If the next perforation cannot be detected even after the elapse of this escape time, it is judged that the film has stopped halfway or the film feeding speed has drastically decreased, and a backup process described later is performed.

In step S32, it is determined whether the perforation detection voltage of the sensor PS2 exceeds the second threshold voltage and the perforation detection signal is output from the comparator CP1. The detection position of the sensor PS2 is set to the perforation P of the next shooting frame Fn + 1.
When the front end YF of Y passes and the perforation detection signal is output from the comparator CP1, step S3
Go to 4. Then, in step S34, the time from the rear end XR of the perforation PX of the photographing frame Fn passing through the detection position of the sensor PS2 to the front end YF of the perforation PY of the next photographing frame Fn + 1 and the distance therebetween. The winding speed Vo3 is calculated based on

In step S35, the calculated winding speed V
It is determined whether or not o3 is equal to or higher than a predetermined speed V5, and Vo3 is V
If it is 5 or more, it is determined that the winding speed is high, and the process proceeds to step S37 to control the drive circuit MD to control the motor M.
Is driven at a duty of 50%. On the other hand, the winding speed V
If o3 is smaller than the predetermined speed V5, the process proceeds to step S36, and it is determined whether or not the winding speed Vo3 is equal to or higher than the predetermined speed V6. Here, V5 <V6. Hoisting speed Vo3
Is equal to or higher than the predetermined speed V6, it is determined that the winding speed is medium speed, and the process proceeds to step S38, and the drive circuit MD drives the motor M with a duty of 75%. When the hoisting speed Vo3 is lower than the predetermined speed V6, it is determined that the hoisting speed is low, the process proceeds to step S39, and the drive circuit M
The motor M is driven by D with a duty of 100%.

As described above, the winding speed is measured again immediately before the stop position during the deceleration period, and the duty of the motor immediately before the stop position is reset according to the winding speed. Even if the deceleration is performed, the deceleration can be corrected to the correct deceleration with respect to the target stop position. Also, the maximum time to pass between the perforations is set as the escape time, and if the escape time does not pass between the perforations, the brake is released and the motor is driven at 100% duty. Therefore, the film does not stop midway or the film feeding speed does not suddenly decrease, and the reliability of the film feeding can be improved.

On the other hand, in step S32, the front end Y of the perforation PY of the photographing frame Fn + 1 is detected by the sensor PS2.
If F is not detected, the process proceeds to step S33, and it is determined whether or not the escape time set timer has timed out and the escape time has ended. If the escape time has not ended, the process returns to step S32 to escape. If the time has ended, it is judged that the film has stopped halfway or the feeding speed has drastically decreased, and the process proceeds to step S39, where the drive circuit MD drives the motor MD.
Is driven at a duty of 100%.

In step S40, the maximum time for the perforation PY of the photographing frame Fn + 1 to pass through the detection position of the sensor PS2 is set as the escape time in the timer, and the timer is started. In step S41, the sensor PS
It is determined whether or not the perforation detection voltage of 2 is lower than the second threshold voltage and the film detection signal is output from the comparator CP1. Sensor P
When the rear end YR of the perforation PY of the photographing frame Fn + 1 passes the detection position of S2 and the film detection signal is output from the comparator CP1, the process proceeds to step S45.
The drive circuit MD brakes the motor M to stop the film winding. FIG. 9D shows a state in which one frame of this film has been wound up. Further step S4
In step 6, the supply of power to the sensor PS2 is stopped, the process returns to step S3, and the above-described processing is repeated as long as the camera is powered on by the switch SW1.

On the other hand, in step S41, the comparator C
When the film detection signal is not output from P1, the process proceeds to step S42, and the timer determines whether or not the escape time has ended. When the escape time ends, it is determined that the film has stopped halfway or the feeding speed has suddenly decreased, and the process proceeds to step S43 to drive the motor M with a duty of 100%. Further, in step S44, it is determined again whether or not the film detection signal is output from the comparator CP1. When the film detection signal is output, the process proceeds to step S45, and the motor M is braked and stopped.

As described above, since the two sensors PS1 and PS2 for perforation detection are separately supplied with power only during the period in which they need to be operated, the power consumption of the battery can be saved. Also,
For two perforation detection sensors, a load resistor R for converting the sensor output current into a voltage
And the output of the sensors PS1 and PS2 from the arithmetic and control unit CP
Since U and the comparator CP1 for converting into a readable digital signal are commonly used, the number of parts is reduced and the installation space for that is not required, and the cost and the power consumption of the battery can be reduced. Furthermore, the sensors PS1 and PS2 input via the comparator CP1
Since the threshold signal for PS1 and the threshold signal for PS2 are switched based on the perforation detection result of, the digital threshold signals are sent to the D / A converter, converted into analog voltage and set in the comparator CP1, respectively. The detection level of each sensor can be set separately, and accurate perforation can be detected. Moreover, the comparator can be shared, the number of parts is reduced, and the installation space for that amount is not required. The power consumption of the battery can be reduced. Furthermore, the sensors PS1 and PS2
The digital value of the threshold voltage for
The digital value of the threshold signal of each sensor is stored in the EPROM and is read out from the memory EEPROM during the period in which each sensor needs to be operated, converted into an analog value, and the comparator CP1
Since the threshold voltage is set to, the threshold voltage can be set in advance for each sensor according to the perforation detection conditions and the characteristic difference between the sensors, and the perforation can be accurately detected.

Although the normal wind type camera has been described as an example in the above embodiment, a prewind type camera in which the film is once wound on the camera prior to photographing and is rewound into the cartridge while photographing is performed. The present invention can also be applied to.

Further, in the above-mentioned embodiment, the film having two perforations as shown in FIG. 2 is described as an example. However, the number of perforations for each photographing frame is three or more. Good.

In the above-described embodiment, 3 is set depending on the winding speed.
Although the duty of each type is set, there may be four or more types of duty, and the value of the duty is not limited to the above embodiment. Further, the duty may be continuously changed according to the winding speed.

In the above-described embodiment, the example of performing the setting of the escape time and the backup process when the escape time has elapsed during the deceleration of the film has been shown. However, before the deceleration of the film, the predetermined escape time elapses. However, if the passage of the film in the predetermined section is not detected at the detection position of the sensor, a predetermined backup process may be performed. Further, if the passage of the predetermined perforation is not detected at the detection position of the sensor even after the predetermined escape time has elapsed from the start of the feeding of the film, a predetermined backup process may be performed. Furthermore, the content of the backup process is not limited to the above-mentioned embodiment.

In the configuration of the above embodiment, the drive circuit M
D and the motor M serve as the feeding means, and the sensors PS1 and P
S2 is the detecting means, load resistor R is the signal converting means, comparator CP1 is the comparing means, and arithmetic and control unit CPU
The control means and the power supply means by the arithmetic and control unit CPU
And the D / A converter constitute threshold voltage supply means, respectively.

[0037]

As described above, according to the present invention, the output current of each detecting means is converted into a voltage by the signal converting means provided in common to a plurality of detecting means, and this voltage is compared with the threshold voltage. However, since the film feeding is controlled based on the comparison result, it is not necessary to provide the signal conversion means and the comparison means for each detection means, and the number of parts is reduced and the installation space is reduced accordingly. Is unnecessary, and the cost and the power consumption of the battery can be reduced. Further, the power consumption of the battery can be saved because the power is separately supplied to each of the detection means only during the period when the detection means needs to be operated. Further, since the threshold voltage corresponding to each detection means is supplied to the comparison means, the detection level of each detection means can be set separately, and accurate perforation can be detected.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an embodiment.

FIG. 2 is a diagram showing a positional relationship between a film and a sensor used in one embodiment.

FIG. 3 is a flowchart showing a control program for winding one frame of film.

FIG. 4 is a flowchart showing a control program for winding one frame of film, following FIG. 3;

FIG. 5 is a flowchart showing a control program for winding one frame of film, following FIG.

FIG. 6 is a flowchart following FIG. 5, showing a control program for winding one frame of film.

FIG. 7 is a flowchart showing a control program when one frame of film is wound, following FIG. 6;

FIG. 8 is a flowchart showing a control program subsequent to FIG. 7 when winding one film frame.

FIG. 9 is a view for explaining the one-frame winding operation of the film of one embodiment.

[Explanation of symbols]

 CPU arithmetic and control unit PS1, PS2 sensor CP1 comparator R load resistor EEPROM memory MD drive circuit M motor D / A D / A converter CON control circuit

Claims (5)

[Claims] 1. A feeding means for feeding a film, a plurality of detecting means for detecting a predetermined position on the film, and a plurality of detecting means provided in common to the plurality of detecting means. A signal converting means for converting the voltage into a voltage, a comparing means for comparing the output voltage of the signal converting means with a threshold voltage, and a control for controlling the feeding of the film by the feeding means based on the comparison result of the comparing means. A film feed device for a camera comprising: 2. The film feeding device for a camera according to claim 1, wherein the detection means is an optical sensor that outputs a current proportional to the amount of incident light, and the signal conversion means is an output terminal of the optical sensor. A film feeding device for a camera, which is a resistor connected to the terminal and generating a voltage proportional to the current output from the terminal. 3. The film feeding device for a camera according to claim 1, wherein power is supplied to each of the detecting means separately only during a period in which it is necessary to operate each of the detecting means. A film feeding apparatus for a camera, characterized by comprising: 4. The film feeding device for a camera according to claim 1, further comprising a threshold voltage supplying means for supplying a threshold voltage corresponding to each of the detecting means to the comparing means. A film feeding device for a camera. 5. The film feeding device for a camera according to claim 1, wherein the film is a film in which a plurality of perforations are provided at unequal intervals and at the same position on each photographing frame. A film feeding apparatus for a camera, wherein the detecting means detects a perforation.