JPH0784301A - camera - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a camera capable of easily determining a threshold level of a photosensor even in the case of a film having no perforation holes in the first frame. [Configuration] 1 is a microcomputer 1, 8 which is a control device of the camera
Is a motor, 9 is a motor drive circuit, a motor driver, and SW
1, SW2 is a switch interlocked with the release switch, 7
Is a distance measuring circuit, 6 is a lens microcomputer, and 5 is a lens communication circuit, which supplies electric power to the lens when the camera is in operation and communicates between the microcomputer 1 and the lens microcomputer 6. Reference numeral 2 is an EEPROM used for storing data necessary for camera control and the state of the camera. Reference numeral 3 is a photometric circuit, which starts a photometric operation in response to a photometric start signal from the microcomputer 1. A temperature sensor 4 measures the temperature of the camera. The temperature sensor output is connected to the A / D port of the camera. ph
Photosensors 1 and ph2 are used to control the film feeding. The output of the photo sensor is A of the microcomputer 1.
/ D port.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for feeding a film having two or more perforations on one screen by using a plurality of photosensors.

[0002]

BACKGROUND OF THE INVENTION Traditionally, the first part of the film (ie,
The threshold level of the photosensor was determined by the perforation holes of the portion before the first frame). The following is a specific method for determining the threshold value. (1) Method of determining from maximum and minimum values of sensor output (2) Method of determining from maximum inclination value (3) Method of directly storing threshold value (4) Frequency distribution of A / D value There is a method of obtaining and using the median as a threshold. Further, as a method for controlling the feeding using two photo sensors, there is JP-A-4-328536.

[0003]

However, the above method is premised on that the perforation hole is also present in the first portion of the film and the threshold value is determined in that portion. Therefore, according to the conventional method, it is very difficult to determine the threshold level of the photosensor in the case of a film having no perforation holes up to the first frame.

In the above method (1), since there is no perforation hole at the beginning of the film, it is impossible to set an appropriate threshold level from the maximum and minimum values.
In the method (2), the threshold level cannot be obtained from the slope because there is no perforation hole in the first part of the film. The method (3) cannot deal with different films. The method (4) is based on the premise that the perforation holes are continuously arranged at equal intervals. Therefore, if the film has no perforation holes at the beginning of the film, an appropriate threshold level cannot be set. .

The present invention has been made to solve the above problems, and provides a camera capable of easily determining the threshold level of a photosensor even in the case of a film having no perforation holes up to the first frame. With the goal.

[0006]

In order to achieve the above object, the camera of the present invention according to claim 1 detects a perforation by using a photosensor and controls feeding, and when a film is not present, Means for storing the photosensor output, means for feeding the film,
A unit for A / D converting the output of the photo sensor, a unit for repeating the A / D conversion during film feeding to detect the maximum value thereof, and a threshold of the photo sensor from the value and the maximum value stored in the storage unit. And means for storing the photosensor output when there is no film, means for feeding the film, and A / D conversion of the photosensor output. Means for measuring the predetermined time after the start of film feeding,
The camera is provided with a means for determining a threshold value of the photosensor from the photosensor output before the film feeding is started and the photosensor output after a predetermined time has elapsed after the film feeding is started. Item 3, at least first and second photosensor means for outputting a film perforation signal, and at least two on one screen.
Control means for generating a control timing signal corresponding to the first photosensor means from a feeding means for feeding a film having one perforation hole and a perforation signal when the film is fed by the feeding means. Generating means, first storage means for storing the first perforation signal output from the second photosensor means when there is no film, and second storage means when the timing signal of the control timing generating means is generated. Second storage means for storing the second perforation signal output from the photosensor means, and perforation holes of the second sensor from the first and second perforation signals stored in the first and second storage means. A determination means for determining a determination threshold, and the threshold and the perforation determined by the determination means. Detecting perforations by comparing the Deployment signal, but with a feeding control device for feeding controlling the film.

[0007]

According to the present invention, the threshold value is determined based on the sensor output before the start of film feeding and the sensor output value after a fixed time from the start of feeding. Since the film is not pulled out when the cartridge is just put in the camera,
The value at this time is stored as the level without film.
Then, the film is sent out, the value when there is a film after a certain period of time is obtained, and the threshold value is determined from these two values.
Unlike conventional films, there is no perforation hole up to the first frame, so there is no need to repeat A / D conversion to determine the threshold level.

As another method, the value without film can be stored in advance in the EEPROM and the threshold level can be determined from the value and the maximum value. The value without film changes depending on the sensor, but does not change depending on the film. Therefore, the value may be stored in advance and only the sensor output value when the film exists may be obtained for each film.

[0009]

[Embodiment] First, an electric circuit of a main part of a camera for realizing this embodiment will be described. FIG. 1 is an electric control block diagram for explaining a circuit of a main part of the camera. In the figure, reference numeral 1 denotes a camera control device, which is, for example, a 1-chip microcomputer (hereinafter referred to as a microcomputer) having a CPU (central processing unit), a ROM, a RAM, and an A / D conversion function. The microcomputer 1 performs a series of camera operations such as an automatic exposure control function, an automatic focus adjustment function, film winding and rewinding in accordance with a camera sequence program stored in a ROM.

Numeral 8 is a motor for raising and lowering the film feeding mirror and for charging the shutter spring. Reference numeral 9 denotes a motor drive circuit motor driver, which controls forward / reverse rotation of the motor by a control signal from the microcomputer. SW
SW1 and SW2 are switches linked to the release switch.
SW1 turns “ON” when the release button is pressed halfway, and SW2 turns “O” when the release button is pressed continuously.
N ”. The microcomputer 1 performs photometry and distance measurement with SW1 "ON" and performs exposure control and subsequent film winding with SW2 "ON" as a trigger.

Reference numeral 7 denotes a distance measuring circuit which starts accumulation of a distance measuring sensor (not shown) in response to a distance measurement start signal from the microcomputer 1 and, when the accumulation of the distance measuring sensor is completed, synchronizes with a control signal sent from the microcomputer 1. And outputs the data to the microcomputer 1. The microcomputer 1 performs focus detection calculation on the data of the distance measuring sensor to perform the distance measuring operation.

A lens microcomputer 6 communicates with the microcomputer 1 on the camera body side to transmit lens-specific data to the camera body and to receive a drive command from the camera body, and to set an optical system of a lens (not shown). In addition to driving to a predetermined position, it controls a diaphragm (not shown). Reference numeral 5 denotes a lens communication circuit, which supplies electric power to the lens when the camera is in operation and communicates between the microcomputer 1 and the lens microcomputer 6.

An EEPROM 2 is used to store data necessary for camera control and the state of the camera. Reference numeral 3 denotes a photometry circuit, which starts a photometry operation in response to a photometry start signal from the microcomputer 1. A temperature sensor 4 measures the temperature of the camera. The temperature sensor output is connected to the A / D port of the camera. PH1 and PH2 are used by the photosensor to control the feeding of the film. The output of the photo sensor is connected to the A / D port of the microcomputer 1.

FIG. 4 is a perspective view of the cartridge, the photosensor and the take-up spool. The drawing and the take-up of the film will be described with reference to this figure.

In the figure, photo sensors ph1 and ph2 detect perforation holes in the film. The CTR is a film cartridge in which a film is wound. The FK is a fork that feeds the film and winds it at the end of shooting. SPL is a spool for winding a film.

FIG. 4A shows a state in which the cartridge is inserted inside the camera. The film is rolled into the cartridge and the leading edge of the film is not exposed. Therefore, the photosensors ph1 and ph2 have no film portion. When the fork FK connected to the cartridge is rotated in the film feeding direction from this state, the leading end portion of the film is exposed as shown in FIG. 4B. In FIG. 4 (b),
The film is not wound around the spool SPL, and the photosensors ph1 and ph2 face a part having no perforation hole of the film. In addition, fork F
When K is rotated, the leading end of the film winds around the spool as shown in FIG. The speed of the spool SPL is faster than the speed of the fork FK and winds the film. In FIG. 4C, the film is at the position where the film is just taken.

FIG. 2 shows a film and photosensors ph1 and p.
It is a figure which shows about the relationship of h2. For convenience of explanation, the film is shown expanded in a plane, but the film is wound at the SPL position and the film cartridge is placed at the CTR position. The film is fed from right to left in the figure. In FR, when the film is loaded by the leader portion of the film, this portion is taken up by the take-up spool SPL. It should be noted that this part cannot be photographed. A1, A2, and A3 are first, second, and third shooting screens, respectively. P0 to P6 are perforations, and P1 and P2 are perforations corresponding to the shooting screen A1. (There are P3 and P4 corresponding to the screen A2, and P5 and P6 corresponding to the screen A3.) The photosensors ph1 and ph2 are shown in FIG. 2 when the film is stopped at the position for photographing the screen A1. They are arranged in a positional relationship.

FIG. 3 shows the first film photographing screen (A
It is an output waveform of each sensor when loaded up to 1). ph1out indicates the output of the photosensor ph1, and ph2out indicates the output of the photosensor ph2.
V20 is a sensor output value when the photo sensor ph2 is not detecting a film, and V21 is a sensor output value when the photo sensor ph2 is detecting a film. V1
0 is a sensor output value when the photo sensor ph1 is not detecting a film, and V11 is a sensor output value when the photo sensor ph1 is detecting a film. eg1, e
g2 is an edge generated when the leading edge of the film is applied to the photosensors ph1 and ph2, respectively. ed
3, ed4 are signals generated when the perforations P0 and P1 pass through the photo sensor ph2 portion, and ed
Reference numerals 5 and ed6 are signals generated when the perforations P0 and P1 pass through the photosensor ph1 portion.

FIG. 5 is a flowchart of film loading. The film loading routine is called from a main routine (not shown) when the back cover is opened and the film cartridge is loaded. Film loading will be described with reference to FIG. The following steps are abbreviated as S.

The film loading subroutine starts from here (S01). Next, it is determined whether the back cover is closed (S02). The determination is repeated until it is closed, and when it is closed, the process proceeds to S03, and the presence or absence of the cartridge is determined (S03). If there is no cartridge, the process branches to S27 and the subroutine ends. If there is a cartridge, the process proceeds to S04. And the photo sensor 2
A / D conversion is performed (S04). The A / D converted value is V
20 is stored in a predetermined RAM area.

Next, A / D conversion of the photo sensor 1 is performed (S05). The A / D converted value is V10 and the predetermined R
It is stored in the AM area. Then, the driving of the feeding motor is started (S06). Then, the preset time is waited (S07). This sets the time during which the film is reliably pulled out from the film cartridge and the first frame of the shooting screen is not wound on the winding spool. For example, when the feeding speed of the motor changes depending on the power supply voltage, several values are prepared and the wait time is switched depending on the power supply voltage. After a predetermined time,
The A / D conversion of the photo sensor 2 is performed again (S08). A
The value obtained by the / D conversion is stored in a predetermined RAM area as V21.

Find the difference between A / D converted values v20 and v21
Therefore, determine whether the difference is greater than a certain value
(S09). If the difference is small, the film is a cartridge
Since it is not correctly sent from S27,
And the subroutine ends. Also, v20 and
v21 is used to determine the threshold value of the photo sensor ph2
(S10). For example, the threshold vth2 of the rising edge
u is vth2u = (v20 + v21) × 0.6 The falling edge threshold vth2d is vth2d = (v20 + v21) It becomes × 0.4.

Next, the photo sensor ph1 and the photo sensor
Wait at the interval of ph2 for the time the film advances
(S11). Then, after a predetermined time, the photo sensor
A / D conversion of 1 is performed (S12). The A / D converted value is
It is stored in a predetermined RAM area as V11. v10
And v11 are used to determine the threshold of the photo sensor ph1
It For example, the threshold vth1u of the rising edge is vth1u = (v10 + v11) × 0.6 The falling edge threshold vth1d is vth1d = (v10 + v11) It becomes × 0.4.

Here, the counter for counting the edges is initialized (S14). Then, A of the photo sensor 2
/ D conversion is performed (S15). The threshold vth2d of the falling edge determined in S10 is compared with the A / D converted value (S16). While the output of A / D conversion is larger than the threshold value vth2d, S15 and S16 are repeated.

The A / D converted value of the photo sensor 2 is vth2
When it becomes smaller than d, the process proceeds to the next step, and the A / D conversion of the photo sensor 2 is continuously performed (S17). next,
The threshold vth2u of the rising edge determined in S8 and A
The / D converted values are compared (S18). If the sensor output is smaller than the threshold value, it is not a rising edge, so S1
Returning to 7, the A / D conversion is repeated. If the sensor output is larger than the threshold value, it is determined to be a rising edge and the process proceeds to S19,
It is determined whether the edge is the second edge. If it is not the second one, the process returns to S15 and the edge detection is repeated. If it is the second edge, the process proceeds to S20. In S14 to S19, two rising edges eg3 and eg4 in FIG. 3 are detected.

Next, A / D conversion of the photosensor 1 is performed (S20), and the falling edge threshold vth1d determined in S13 is compared with the A / D converted value (S21).
While the output of A / D conversion is larger than the threshold value vth1d, S2
0 and S21 are repeated. If the A / D converted value becomes smaller than the threshold value, the falling edge is detected.
Proceed to and perform A / D conversion of the photo sensor 1 (S2
2). Next, the threshold vth1u of the rising edge determined in S13 is compared with the A / D converted value (S23).
If the sensor output is smaller than the threshold value vth1u, it is not a rising edge, and therefore the process returns to S22 to repeat the A / D conversion. If the sensor output is larger than the threshold value, it is determined to be a rising edge, and the process proceeds to S24.

Further, it is judged whether the edge is the first one (S24). If it is the first (eg 5 in FIG. 3), the process proceeds to S25. Here, the motor is duty-driven to stop the motor (S25). After that, the process returns to S20 to detect the next edge. Then, the rising edge detected in S24 is not the first rising edge (the edge in FIG. 3eg6 is determined).
The process proceeds to S26. In this step, the motor is stopped and the film is stopped at the shooting position of the first sheet. afterwards,
The loading flowchart is ended and the process returns (S27).

In the present embodiment, the threshold value of the photosensor is determined from the output of the photosensor before the film is fed out and the output of the photosensor after a fixed time has passed after the film is fed out to determine the threshold value of the photosensor until the first frame. The threshold level can be easily determined even for a film without a film.

[Embodiment 2] Here, another method for feeding a film by a photo sensor will be described. Figure 8
Is the output waveform of each sensor when the film is loaded up to the first shooting screen (A1). ph1out
Indicates the output of the photo sensor ph1, and ph2out indicates the output of the photo sensor ph2. V2R is a sensor output value when the photo sensor ph2 is not detecting a film, which is measured in advance and stored in the EEPROM or the like of the camera. max2 is the maximum value of the sensor output value when the photo sensor ph2 is detecting the film. V
1R is a sensor output value when the photo sensor ph1 is not detecting a film, and a value measured in advance like V2 is stored in the EEPROM. max1 is the maximum value when the photo sensor ph1 detects a film.
eg1 to eg6 are the same as those in FIG.

FIG. 6 is a flow chart of film loading. The film loading routine is called from a main routine (not shown) when the back cover is opened and a film cartridge is loaded. The film loading will be described with reference to FIG. The film loading subroutine starts (S101), and it is determined whether the back cover is closed (S102). The determination is repeated until it is closed, and when it is closed, the process proceeds to S103. Then, the presence or absence of the cartridge is determined (S103). If there is no cartridge, the process branches to S129 to end the subroutine. If there is a cartridge, proceed to S104,
Start driving the feeding motor. Then, in order to obtain the maximum value, max1 and max2 are initialized (S10).
5). A / D conversion of the photo sensor 2 is performed (S10
6). The A / D converted value is stored as V2 in a predetermined RAM area.

Next, the output v2 of the photosensor 2 obtained in S106 is compared with the maximum value max2. If v2 is large, the process branches to S108, and the maximum value max2 is replaced with v2 (S108). If the output v2 of the photo sensor 2 is smaller than the maximum value max2 in S107, the process proceeds to S109.

Next, A / D conversion of the photo sensor 1 is performed (S109). The A / D converted value is v1 and is a predetermined R
It is stored in the AM area. Further, the output v1 of the photo sensor 1 obtained in S109 is compared with the maximum value max1 to obtain v
If 1 is large, the process branches to S111, and the maximum values max1 and v
Swap 1 If not, the process proceeds to S112, and it is determined whether the maximum value has been detected. The conditions for the determination are, for example, whether or not a certain time has elapsed from the start of driving the motor, the detected maximum value exceeds a certain level, and the output of the photo sensor continuously decreases. If the maximum value detection has not ended, S106 to S112 are repeated, and if the maximum value detection has ended, the process proceeds to S113.

Next, each sensor is communicated with the EEPROM.
The output value without film is obtained (S113). PHOTOSE
The output of the sensor ph2 without film is V2R, and
The output value of the sensor ph1 without a film is V1R. R
If there is no film in the EEPROM beforehand,
The output of the photo sensor is stored and the film is loaded.
It is not necessary to carry out A / D conversion every time it is changed. Also Phil
When the cartridge is set as shown in Fig. 4 (b)
However, the threshold value will not be erroneously determined. And V2R
And max2 are used to determine the threshold of the photo sensor ph2
(S114, S115). For example, falling edge
The threshold vth2d of V is: vth2d = (V2R + max2) × 0.4 The threshold vth2u of the rising edge is: vth2u = (V2R + max2) It becomes × 0.6.

Photosensor using V1R and max1
The threshold value of ph1 is determined (S114). For example,
The threshold vth1d of the sharp edge is vth1d = (V1R + max1) × 0.4 The rising edge threshold value vth1u is vth1u = (V1R + max1) It becomes × 0.6.

Next, the counter for counting the edges is initialized (S116). Then, A of the photo sensor 2
/ D conversion is performed (S117). Further, the falling edge threshold vth2d determined in S114 is compared with the A / D converted value (S118). The output of A / D conversion is the threshold value v
While it is larger than th2d, S117 and S118 are repeated.

When the A / D converted output becomes smaller than the threshold value vth2, the process proceeds to the next step, where the A / D of the photo sensor 2 is
D conversion is performed (S119). Furthermore, the threshold vth2u of the rising edge determined in S114 is compared with the A / D converted value (S120). If the sensor output is smaller than the threshold value, it is not a rising edge, so the process returns to S119,
Repeat A / D conversion. If the sensor output is larger than the threshold value, it is determined to be a rising edge, and the process proceeds to S121. Then, it is determined whether the edge is the second edge. If it is not the second one, the process returns to S117 to repeat the edge detection. If it is the second edge, proceed to S122. In S117 to S121, two rising edges eg3 and eg4 in FIG. 8 are detected.

Next, A / D conversion of the photo sensor 1 is performed (S122). Then, the falling edge threshold vth1d determined in S115 is compared with the A / D converted value (S123). S122 and S123 are repeated until the output of A / D conversion becomes smaller than the threshold again. When the A / D-converted value becomes smaller than the threshold value, the falling edge is detected. Therefore, the process proceeds to S124, and the A / D conversion of the photosensor 1 is performed.

Next, the threshold vth1u of the rising edge determined in S115 is compared with the A / D converted value (S).
125). If the sensor output is smaller than the threshold value vth1d, it is not a rising edge, and therefore the process returns to S124 and the A / D
Repeat the conversion. If the sensor output is larger than the threshold value, it is determined to be a rising edge and the process proceeds to the next. Here, it is determined whether the edge is the first edge (S126). The first (Fig. 8eg
If 5), proceed to S127. If not the first (Fig. 8eg
Then, the process proceeds to S128. If the edge is the first edge, the motor is duty driven to stop the motor in S127. After that, the process returns to S122 to detect the next edge. If the rising edge detected in S126 is not the first one, the process proceeds to S128. In this step, the motor is stopped and the film stops at the shooting position of the first sheet. Then, the loading flowchart is terminated and the process returns (S129).

In this embodiment, the output of the photosensor without the film is stored in the memory, and the threshold value of the photosensor is determined from the value and the maximum value of the output of the photosensor when the film is fed. As a result, the threshold level can be easily determined even with a film having no perforation holes up to the first frame. Furthermore, the optimum sensor threshold can be determined even when the output cannot be obtained when the film is not applied to the photo sensor.

[Third Embodiment] Here, another method for feeding a film by a photo sensor will be described. FIG. 9 shows the output waveform of each sensor when the film is loaded up to the first shooting screen (A1). ph
1out indicates the output of the photosensor ph1, and ph2o
ut indicates the output of the photo sensor ph2. eg1, eg
Reference numeral 2 is an edge generated when the front end of the film is applied to the photosensors ph1 and ph2, respectively. eg3
eg4 is a signal generated when the perforations P0 and P1 pass through the photo sensor ph2 portion.
d6 is the perforation P of the photo sensor ph1
This is a signal generated when 0 and P1 pass. V20 is the sensor output value when the photo sensor ph2 is not detecting the film, and V21 is the edge e of the photo sensor ph1.
It is the output value of the sensor ph2 when g2 is detected. V1
0 is a sensor output value when the photo sensor ph1 does not detect a film, and V11 is a sensor output value when the photo sensor ph2 detects an edge eg3.

FIG. 7 is a flow chart of this embodiment of the film. The film loading will be described with reference to FIG. The film loading routine is called from a main routine (not shown) when a film cartridge is loaded (S201). Then, A of the photo sensor 2
/ D conversion is performed (S202). A / D converted value is V2
0 is stored in a predetermined RAM area. After that, the A / D conversion of the photo sensor 1 is performed (S203). A / D
The converted value is stored as V10 in a predetermined RAM area. In step S204, the initial value of the parameter for detecting the edge (eg2) of the photo sensor ph1 is set. The previous output value V00 of the photo sensor ph1 is set to S2.
The edge counter cn is added to the value V10 A / D converted in 03.
t is set to 0 (S204). Then, the driving of the feeding motor is started (S205). Further, A / D conversion of the photo sensor 1 is performed (S206). The A / D converted value is stored as Vad in a predetermined RAM area.

Next, the value Vad obtained by A / D conversion in S206
Is larger than the previous A / D conversion value V00 (S207). If it is larger, the process proceeds to S208, and if not, the process proceeds to S209. If Vad is larger than V00, the edge counter cnt is incremented (S2
08). If not, that is, if the value Vad A / D converted in S206 is smaller than the previous A / D converted value V00, the process branches to S209. Here, the edge counter is cleared. After executing S208 or S209,
The value Vad A / D converted in S206 is stored in V00 (S210).

Next, the edge counter cnt is set to a predetermined threshold value.
It is determined whether cnth is exceeded (S211). Constant
If the sensor output value becomes large consecutively, the edge
To determine. If less than a certain number of times, branch to S206
Then, S206 to S211 are repeated. Exceeded a certain number of times
Then, A / D conversion of the photo sensor 2 is performed (S212).
The A / D converted value is stored in a predetermined RAM area as V21.
Is stored. Furthermore, using V20 and V21,
The threshold value of the sensor ph2 is determined (S213). Rising
The edge threshold vth2u is vth2u = (V20 + V21) × 0.6 The falling edge threshold value vth2d is vth2d = (V20 + V21) It becomes × 0.4.

Next, in S214, a counter for counting edges is initialized. Then, A of the photo sensor 2
/ D conversion is performed (S215). Next, the threshold vth2d of the falling edge determined in S213 is compared with the A / D converted value (S216). The output of A / D conversion is the threshold value v
While it is larger than th2d, S215 and S216 are repeated. When it becomes smaller, the A / D of the photo sensor 2
Conversion is performed (S217).

Next, the threshold vth2u of the rising edge determined in S213 is compared with the A / D converted value (S).
218). If the sensor output is smaller than the threshold value, it is not a rising edge, and therefore the process returns to S217 to repeat the A / D conversion. If the sensor output is larger than the threshold value, it is determined to be a rising edge, and the process proceeds to S219. And the edge is 2
It is determined whether it is the second eye (S219). If it is not the second one (the first edge, FIG. 9eg3), branch to S228,
The threshold value of the photo sensor ph1 is determined. If it is the second edge, proceed to S220.

If it is the first edge, in S228
Performs A / D conversion of the photo sensor 1. A / D conversion
The calculated value is stored as V11 in a predetermined RAM area.
Then, using V10 and V11, the photo sensor ph1
The threshold of is determined (S229). For example,
Threshold value vth1u of the edge is vth1u = (v10 + v11) × 0.6 The falling edge threshold vth1d is vth1d = (v10 + v11) It becomes × 0.4. After the threshold is determined, the process returns to S214 to detect an edge.
repeat.

When the detection of the two rising edges (eg3 and eg4 in FIG. 9) is completed in S214 to S219, the process proceeds to S220. Here, A of the photo sensor 1
/ D conversion is performed. Next, the threshold vth1d of the falling edge determined in S229 is compared with the A / D converted value (S221). While the output of A / D conversion is larger than the threshold,
S220 and S221 are repeated. When the A / D-converted value becomes smaller than the threshold value, the falling edge is detected, and the process proceeds to S222.

Therefore, A / D conversion of the photo sensor 1 is performed (S222). Next, the threshold vth1u of the rising edge determined in S213 is compared with the A / D converted value (S223). If the sensor output is smaller than the threshold value vth1u, it is not a rising edge, so the process returns to S222, and A
Repeat / D conversion. If the sensor output is larger than the threshold value, it is determined to be a rising edge, and the process proceeds to S224.

Next, it is determined whether the edge is the first edge (S224). If it is the first one (FIG. 9eg5), the process proceeds to S225. If it is not the first one (the edge of FIG. 9eg6 is judged),
Proceed to S226. In S225, the motor is decelerated to stop the motor. After that, the process returns to S220, and the next edge (eg 6 in FIG. 9) is detected.

If the rising edge detected in S224 is not the first one, the process proceeds to S226. In this step, the motor is stopped and the film stops at the shooting position of the first sheet. Then, the flowchart of loading is terminated and the process returns (S227).

In this embodiment, the timing shift between the two photosensors is used to determine the threshold value of the other photosensor at the timing when one sensor detects the edge, so that the perforation holes up to the first frame are detected. The threshold level can be easily determined even for a film without a film.

[0052]

As described above, according to the present invention, in claim 1, the output of the photosensor when there is no film in the photosensor before the film is fed, and the film before the photosensor after the film is fed By determining the threshold value of the photo sensor from the output of the photo sensor after a certain period of time, it is possible to easily determine the threshold level even for a film having no perforation holes up to the first frame.

In the second aspect, the output of the photosensor in the absence of the film does not change even if the film to be fed changes, so this value is stored in the memory. By determining the threshold value of the photosensor from this value and the maximum value of the output of the photosensor when the film is fed, the threshold level can be easily determined even for a film having no perforation holes up to the first frame. Further, even when the output in the state where the film is not applied to the photo sensor cannot be obtained, the optimum sensor threshold value can be determined.

Further, in claim 3, at least first and second photosensor means for outputting a perforation signal of the film, and a feeding means for feeding a film having two perforation holes on at least one screen, From the control timing generating means for generating a control timing signal corresponding to the first photo sensor means from the perforation signal when the film is fed by the feeding means, and the second photo sensor means when the film is not present. First storage means for storing the first perforation signal output and second perforation signal output from the second photosensor means when the timing signal of the control timing generation means is generated are stored. Second storage means and first and second storage means stored in the first and second storage means From the perforation signal the second
Of the sensor for determining the perforation hole determination threshold value, the perforation is detected by comparing the perforation signal with the threshold value determined by the determination means, and a feeding control device for controlling the feeding of the film is provided. Therefore, the film can be fed smoothly.

[Brief description of drawings]

FIG. 1 is an electrical control block diagram for explaining a circuit of a main part of a camera.

FIG. 2 is a diagram showing a relationship between a film and photo sensors ph1 and ph2.

FIG. 3 is a diagram showing output waveforms of photo sensors ph1 and ph2.

FIG. 4 is a perspective view of a cartridge and a photo sensor take-up spool.

FIG. 5 is a flowchart for explaining the first embodiment.

FIG. 6 is a flowchart for explaining a second embodiment.

FIG. 7 is a flowchart for explaining a third embodiment.

FIG. 8 is a time chart of the photo sensor 1 and the photo sensor 2 of the present invention.

FIG. 9 is a time chart of the photo sensor 1 and the photo sensor 2 of the present invention.

[Explanation of symbols]

 ph1 photo sensor ph2 photo sensor 1 microcomputer 2 EEPROM 3 photometric circuit 4 temperature sensor 5 lens communication circuit 6 lens microcomputer 7 ranging circuit 8 motor 9 motor driver

Claims (3)

[Claims] 1. A camera for detecting perforation by using a photo sensor and controlling feeding, a means for storing the photo sensor output when there is no film, a means for feeding the film, and a photo sensor output. A /
A means for D-converting, a means for repeatedly performing A / D conversion during film feeding to detect the maximum value thereof, and a means for determining a threshold value of the photosensor from the value and the maximum value stored in the storage means. A camera characterized by: 2. A camera which detects perforations by using a photosensor and controls feeding, a means for storing the photosensor output when there is no film, a means for feeding the film, and a photosensor output. A /
D conversion means, means for measuring a predetermined time after starting film feeding, the photosensor output before the start of film feeding, and the photosensor threshold after a predetermined time has elapsed after starting film feeding And a means for determining. 3. A at least first and second photosensor means for outputting a perforation signal of the film, a feeding means for feeding a film having two perforation holes on at least one screen, and a film by the feeding means. Control timing generation means for generating a control timing signal corresponding to the first photosensor means from the perforation signal when feeding the film, and the first perforation output from the second photosensor means when there is no film. First storage means for storing a signal, and second storage means for storing a second perforation signal output from the second photosensor means when the timing signal of the control timing generation means is generated, From the first and second perforation signals stored in the first and second storage means, A feeding controller for determining the perforation hole determination threshold of the second sensor, detecting the perforation by comparing the threshold determined by the determining means with the perforation signal, and controlling the feeding of the film. A camera that is equipped with.