JPH06265975A - Camera provided with shutter measuring device - Google Patents

Abstract

PURPOSE:To evade erroneous photographing caused by the defective actuation of a shutter by comparing an actual exposure time and a control shutter time and preventing the shutter from being controlled by a time equal to or shorter than a shutter time thereafter when the shutter is not correctly controlled. CONSTITUTION:An arithmetic means 101 obtaining the exposure time by which the shutter 8 should be controlled and a control means 102 controlling the shutter 8 by the obtained control exposure time are provided. Besides, a measuring means 105 measuring the actual exposure time obtained by the shutter 8 controlled to be driven by the control means 102, a judgement means 103 judging whether the actual exposure time is within the previously decided normal range of actuation or not and an inhibition means 104 inhibiting at least the driving of the shutter by the control exposure time when the actual exposure time is out of the normal range of the actuation are provided. Then, when the actual exposure time is judged to be out of the normal range of the actuation, the shutter is inhibited from being driven by the control exposure time at least at that time when the succeeding photographing is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera provided with a device for detecting a traveling state of a shutter.

[0002]

2. Description of the Related Art Conventionally, in a general single-lens reflex camera, a light flux from a subject is narrowed down by a diaphragm of a lens, and an exposure time on a film is limited by a mechanical shutter. The shutter used in this type of single-lens reflex camera basically consists of two so-called front and rear curtains, and the front curtain covers the aperture opening before exposure. When the shutter button is pressed, the front curtain first retracts from the aperture opening to start exposure on the film screen, and after a predetermined time elapses, the rear curtain operates so as to cover the aperture opening. The traveling of each curtain is performed by a mechanically biased spring force, and the traveling is started by deenergizing the electromagnets that lock the curtain.

By the way, in recent years, speeding up of the shutter such as 1/8000 seconds is becoming an important specification, and speeding up of the strobe synchronization speed is required so that an image can be drawn in a bright environment. For this purpose, the running speed of each curtain (hereinafter referred to as curtain speed) must be dramatically increased by increasing the spring force described above, and the slit width formed by the front curtain and the rear curtain is narrow. Must be controlled so that

[0004]

However, in the shutter having a high curtain speed and a narrow slit width as described above, the following problems may occur. Even if the exposure time is controlled by accurately controlling the energization control timing of the electromagnet, the actual exposure time depends on the mechanical traveling state of each curtain, as is conventional. Factors that vary during shutter speed include the disengagement speed of the locking mechanism with respect to the electromagnet and the variation of the machine running system including the spring. Also, since they necessarily have temperature characteristics and fluctuation characteristics due to aging, they show various changes in total. This phenomenon becomes more remarkable when the traveling speed is increased.

As an abnormal state, for example, the desired shutter speed cannot be obtained and the exposure amount on the film surface becomes excessive or insufficient. There is a possibility that a phenomenon that is not performed, or a phenomenon that overexposure occurs because the curtain does not close, may occur. What is more problematic is that none of the above phenomena is detected during shooting, so the problem cannot be detected unless the film is developed.

It is an object of the present invention to provide a camera which solves the above-mentioned problems by detecting the operating state of the shutter.

[0007]

The present invention will be described with reference to FIG. 1 which is a diagram corresponding to claims. The present invention is directed to an arithmetic means 101 for obtaining an exposure time to be controlled, and the arithmetic means 101
It is applied to a camera provided with the control means 102 which controls the shutter 8 with the control exposure time obtained by. Then, a measuring unit 105 for measuring an actual exposure time obtained by the shutter 8 driven and controlled by the control unit 102, and a judging unit 103 for judging whether or not the actual exposure time is within a predetermined normal operation range. When the determining unit 103 determines that the actual exposure time is out of the normal operating range,
The above-described object is achieved by including the prohibition unit 104 that prohibits the shutter drive at least during the controlled exposure time. In the camera of claim 2, the prohibiting means 104 is
The shutter operation is prohibited at all control exposure times including the control exposure time determined by the determining means 103 to be not within the normal operation range, including the control exposure time.
The camera according to claim 3 is provided with a posture detecting means 29 for detecting the posture of the camera, and the normal operating range is defined by the posture detecting means 29.
It is set in accordance with the posture of the camera detected in. The camera according to claim 4 is provided with a temperature detecting means 30 for detecting the temperature, and the normal operating range is set according to the temperature detected by the temperature detecting means 30. In the camera of claim 5, the prohibiting means 104 includes a setting means for setting a new control exposure time on a lower speed side than the control exposure time determined not to be within the normal operating range, and the control means 102 is newly set. The shutter 8 is driven during the control exposure time. The camera according to claim 6 has a recalculation unit 106 that recalculates the aperture value based on the control exposure time set by the resetting unit 104a.

[0008]

When it is determined that the actual exposure time is out of the normal operating range, the prohibiting means 104 causes
The shutter drive is prohibited at least for the control exposure time at that time. In the camera according to claim 2, when it is determined that the actual exposure time is out of the normal operation range, the control exposure time including the control exposure time in which it is determined that the actual exposure time is not within the normal operation range is included. The shutter operation during the exposure time is prohibited during the subsequent shooting. In the camera according to the third aspect, the normal operating range is set according to the attitude of the camera detected by the attitude detecting means 29. In the camera according to the fourth aspect, the normal operating range is set according to the temperature detected by the temperature detecting means 29. In the camera of claim 5, when it is determined that the actual exposure time is out of the normal operation range, a new control exposure time on the slower side than the control exposure time determined not to be in the normal operation range in subsequent photographing. With shutter 8
Is driven. In the camera of the sixth aspect, the aperture value at which the proper exposure is obtained with the reset control exposure time is calculated.

[0009]

FIG. 2 is a rear view of a camera 1 to which the present invention is applied, showing a state in which a back cover 4 is opened. A film cartridge (not shown) is loaded in the cartridge chamber 5, and the film pulled out from the cartridge passes through the front surface of the aperture 6 and is wound around the spool 7. The pressure plate 9 provided inside the back cover 4 has a function of pressing a film (not shown) against the aperture 6 to maintain the flatness. A shutter 8 provided inside the aperture 6 covers a slightly wider area than the aperture 6 as indicated by a broken line in the figure, and by operating the shutter 8, the subject light through the lens 2 is displayed on the film screen. Guided for a predetermined time. The photographer uses the viewfinder 3 to view the condition of the subject that has passed through the lens 2.
Then, when the release button 10 is pressed, the start of exposure is commanded.

The exposure mode and various conditions can be confirmed on a display device (hereinafter referred to as LCD) 12 such as a liquid crystal. The plurality of setting buttons 11 are operation buttons for arbitrarily setting the operation mode of the camera 1, shooting conditions, etc., and are operated while checking characters on the LCD 12.

FIG. 3 shows an embodiment of an electric circuit block of the camera 1 according to the present invention. This circuit uses a battery 25 as a power source, and the central control is executed by the CPU 32. Photometric device 26
Measures the brightness in each part obtained by dividing the subject into a plurality of parts and inputs a plurality of photometric values to the CPU 32. The film sensitivity detecting device 27 reads the code signal given to the side surface of the loaded film cartridge, and inputs the film sensitivity information to the CPU 32. The switch group 28 includes a manual operation switch including a switch interlocked with the release button 10 and the setting button 11 described above, a timing switch for detecting a sequence state of the camera, and the like, and camera state information is input to the CPU 32 from these switches. To be done. Reference numeral 29 denotes an attitude sensor, which provides CPU 32 with attitude information indicating how to hold the camera, that is, normal position, vertical position, and the like.
To enter. 30 is a temperature sensor, inside the camera,
Particularly, the temperature of the exposed portion of the shutter 8 is detected and input to the CPU 32.

The output from the CPU 32 is the driver circuit 33.
The following drive operation is controlled via the. (1) The LCD 34 is driven to display information on exposure, operation mode setting, warning information, and the like. (2) The shutter 8, more specifically, the operation time interval of the front curtain magnet and the rear curtain magnet, that is, the exposure time is controlled. (3) The diaphragm 35 in the lens 2 is driven to control the amount of passing light. (4) The motor 36 is driven to control film winding, rewinding and feeding, and the urging operation of the shutter drive spring described above. (5) The shutter curtain traveling detection device 37 is controlled. As will be described later, the detection device 37 includes a light emitting diode (hereinafter, L
ED 18 and phototransistor (hereinafter PT)
(Abbreviated as R) 19 and the CPU 32 is LE
D18 is turned on and the signal generated from PTR19 is received.

FIG. 4 shows the positional relationship between the shutter 8 and the aperture 6, and also shows the LED 18 and PTR described above.
19 shows the arrangement of 19. The operation of the shutter 8 will be described in detail with reference to FIG. This figure shows the state before the release button 10 is pressed, that is, before the exposure is started, and the aperture 6 shown by the broken line is covered by the front curtain 15. The front curtain 15 is composed of a plurality of blades, for example, four blades, and is widened while leaving a slight overlapping portion as shown in the figure when the aperture 6 is covered. Similarly, the rear curtain 16 is also composed of a plurality of blades, for example, four blades, and in the state of FIG.
It is piled up above and is made to stand by. Multiple first curtain 1
5, the frontmost blade 20 in the figure and the rearmost blade 21 of the plurality of rear curtains 16 cooperate with each other to form a slit. The slit is a phenomenon that occurs when the control shutter speed is relatively high, and is a phenomenon in which the rear curtain 16 appears in the aperture 6 while the front curtain 15 travels in the aperture 6.

Block 17 is the above-mentioned front curtain magnet,
In addition to the trailing curtain magnet, it is a part that houses the shutter drive spring and the like. Basically, the two electromagnets that lock each curtain separately, two springs for running each curtain, and each blade are also provided. A link mechanism for moving up and down in parallel,
Although not shown, it has a known mechanism.

The exposure operation is performed as follows from the state shown in FIG. First, the front curtain magnet releases the front curtain 15.
As a result, the front curtain 15 retracts so as to be folded below the aperture 6. As a result, there is nothing that blocks the subject light in front of the aperture 6, and the exposure of the film is started. After the lapse of a predetermined time, when the trailing curtain magnet releases the trailing curtain 16, the trailing curtain 16 moves downward from the position shown in the figure so as to spread with respect to the aperture 6. The aperture 6 is now covered by the trailing curtain 16 and the scheduled time exposure is complete. After the exposure is performed as described above, the film is fed by one frame by a winding mechanism (not shown) so that the unexposed portion of the film newly faces the aperture 6 and the curtains 15 and 16 are raised respectively. Pull up to restore to the state before exposure.

As shown in FIG. 4, in the shutter 8, the above-mentioned detection device 37 by the LED 18 and the PTR 19 is provided so as to face each other in the vicinity of the tips of the blades of the front curtain 15 and the rear curtain 16. LED18 and PTR19 are LED1
When the light from 8 is reflected by each blade of the front curtain 15 or each blade of the rear curtain 16, it is arranged so as to enter the PTR 19, and when there is no blade in the emission optical path of the LED 18, There is no incident light on the PTR 19. Therefore, by measuring the output level of the PTR 19, the incident light on the PTR 19, that is, the actual exposure time can be detected.

FIG. 5 shows the operation of the shutter 8 and the PTR1.
9 is a time chart showing the output signal waveform of FIG. 9, showing the traveling state of each curtain, which changes depending on the on / off timing of the magnet (MG) for controlling each curtain, and the detection signal change of the PTR 19. When the release button 10 is pressed, the front and rear curtain magnets are energized and turned on, and the electric locking of each curtain is started. As is known, release button 10
Before the pressing of, the mechanical locking was switched here. After that, by a mechanical operation (not shown), the aperture control of the lens 2 is first executed, and the reflection mirror in the photographing optical path is raised.

Next, the front curtain magnet is turned off. Here, the range of F shown by the broken line indicates the vertical opening of the aperture 6, and the front curtain 15 travels inside the opening F along a locus like a running curve 55 shown in the figure. At this time, the slit forming blade 20 of the front curtain 15 has finished passing the front surface of the detection device 37 in the middle of the running curve 55, so that the output of the PTR 19 is reversed as shown at timing 22 in the figure. After that,
When the trailing blade magnet is turned off after the preset exposure time T has elapsed, the trailing blade 16 crosses the opening F as a running curve 56. At this time, the trailing curtain 16 is the traveling curve 5
At the intermediate position of 6, it starts to pass the front surface of the detection device 37, and the output of the PTR 19 is inverted to the original signal level at timing 23 as shown in the figure.

It is true that the reversal timings 22 and 23 of the PTR 19 obtained as described above are detected in association with the off timings of the front curtain magnet and the rear curtain magnet, and the time from the reversal timings 22 to 23 is calculated. The exposure time (actual exposure time) t of can be measured. For example, even if the exposure control circuit clocks the scheduled time T correctly and drives the magnet at the correct timing, if the actual exposure time t obtained from the PTR 19 is different from the scheduled time T, it is determined that the mechanical system has malfunctioned. it can.

FIG. 6 shows an example of a processing routine by the CPU 32 in FIG. This routine is repeatedly executed while power is being supplied. In step S1, the photometric device 26, the sensitivity detection device 27, the attitude sensor 29, and the temperature sensor 30.
The photometric information, the sensitivity information, the posture information, and the temperature information from are taken in, and in step S2, the calculation is performed based on the photometric information and the sensitivity information to calculate the control shutter time T and the aperture value which are the proper exposure conditions. In step S3, based on the set of the posture information and the temperature information, the limit control shutter time Tlimi
t is read from the table in the CPU 32, and the value is compared with the control shutter time T. Here, the limit control shutter time Tlimit is stored as a set of camera posture information and temperature information when a malfunction of the shutter is detected, in association with the set (see FIG. 8). (See step S28).

When the control shutter time T calculated in step S2 is shorter than the limit control shutter time Tlimit,
In step S4, the control shutter time T is replaced with the limit control shutter time Tlimit, and a warning is issued in step S5. Then, in step S6, an optimum aperture value is calculated based on the limited limit control shutter time Tlimit. In step S7, the exposure conditions obtained above are set to L
Display on CD34. When the control shutter time T is shorter than the limit control shutter time Tlimit, the limit control shutter time Tlimit and the aperture value recalculated in step S6 are displayed, and the control shutter time T is equal to or more than the limit control shutter time Tlimit. In this case, the control shutter time and the aperture value calculated in step S2 are displayed.

In step S8, it is determined whether the release button 10 has been pressed through the switch detection group 28. If it has not been pressed, the process returns to step S1 to repeat the above process. When the release button 10 is pressed, the process proceeds to step S9, first the front and rear curtain magnets are turned on, and in step S10, a reflecting mirror (not shown) is raised to retract from the photographing optical path, and the diaphragm 35 is set to a predetermined diaphragm opening. Control to be. In step S11, a shutter routine for controlling the exposure of the film by opening and closing the shutter 8 and a shutter curtain traveling state detection routine by the detection device 37 are executed. Details of the control will be described in detail with reference to FIGS. In step S12, since the exposure operation is completed, the motor 36 is normally rotated to feed the film, and
Charge each camera by returning it to its initial position. As a result, since the exposure operation has completed one cycle, the process returns to step S1 and the above processing is repeated.

7 and 8 show the above routine step S.
11 is a detailed example of 11. In step S15, step S
2 or the shutter time T to be controlled (control shutter time) T obtained in step S4 is read. In step S16, the energization of the front curtain magnet is terminated, and the front curtain 15 starts running. After this, step S17 and step S
The processes starting from 18 are executed at the same time.

In step S17, the control shutter time T
Start timing. In step S18, step S1
At the same time as 7, the lighting of the LED 18 is started, and step S19 is started.
At, the control waits for the output of the PTR 19 to reverse (rise) after the passage of the front curtain 15. The timing at which this is affirmed corresponds to the timing 22 in FIG. 5, and at the timing at which step S19 is affirmed, the process proceeds to step S20 to start measuring the actual exposure time t.

As can be seen from the time chart of FIG. 5, the control shutter time T in this embodiment is set to be sufficiently longer than each curtain running time for the sake of simplicity. By making such an assumption, it is easy to understand because the control shutter time T is completely timed after the actual exposure time t is started to be timed. When the control shutter time T is extremely short and the timing of the control shutter time T ends earlier than the timing of the actual exposure time t starts, the timing of the control shutter time T is started and the LED 18 is turned on at the same time. While waiting for the end of the timing, on the other hand, the timing of the actual exposure time t is started by interrupting the output reversal (rising) of the PTR 19, and the timing of t is terminated by the reversal (falling) of the output of the PTR 19. It suffices to perform processing.

In step S21, the control shutter time T
Wait for the clock to complete. When the timing of the control shutter time T is completed, in step S22, the energization of the trailing curtain magnet is terminated and the trailing curtain 16 starts running. Step S2
In 3, the rear curtain 16 starts crossing the detection device 37 and the PTR
Wait for the output of 19 to reverse (fall). When it is reversed, the clocking of the clocking time t is completed in step S24, t is obtained, and the LED 18 is turned off in step S25 because the measurement is completed.

Next, in step S26, it is determined whether or not the measured time t, which is the actual exposure time, exceeds the longer limit time Tmax of the control shutter time T controlled by the circuit. When the measured time t is equal to or shorter than the control shutter time T, the process proceeds to step S27. Step S2
At 7, it is determined whether the measured time t exceeds (shorter) the limit time Tmin of the shorter control shutter time T.
The measurement time t is each limit time Tmax of the control shutter time T,
Only when Tmin is not exceeded, the process bypasses step S28 and returns to step S12 in FIG.

The process proceeds to step S28 when the measurement time t exceeds either one of the limit times Tmax or Tmin of the control shutter time T, and the mechanical system of the shutter 8 operates correctly for some reason. Since it is considered that there is no control shutter time, in step S28, a limit control shutter time Tlimit which is, for example, 1/3 step later than the calculated control shutter time T is set. In this case, the limit control shutter time Tlimit is stored in the memory of the CPU 32 in association with the set of the posture and temperature of the camera at that time. As described in step S3, the control including the subsequent display is executed within the range of the shutter speed equal to or later than the limit control shutter time Tlimit. The upper limit time Tmax and the lower limit time Tmin are set for each calculated control shutter time, and are set to ± 1/3 steps centered on the control shutter time, for example.

As described above, according to the present invention, when the measured shutter speed is abnormal, the control in the direction faster than the shutter speed is not selected thereafter, and safe control is performed. become. For example, the specification is 1/80
1/40 with camera prepared from 00 seconds to 1 second
When it is determined that the actual measurement time when controlling 00 seconds is abnormal, the shutter time from 1/4000 seconds to 1/8000 seconds will not be selected from the next time and 1/4000 seconds will not be included. For example, a shutter speed slower by 1/3 step (1/320
0) The control is executed only in the following range.

FIG. 9 shows the LCD when the shutter speed is normal.
34 is an example of a display segment on 34. In the segment 40, the selected mode is the program mode, and in the segments 41 and 42, the shutter speed calculated at step S2 and the aperture value are 1/4000 and 5.6, respectively.
Is shown. In the case of this figure, step S3 is negatively determined based on the past measurement results, the aperture value is adopted without being changed and the warning is not displayed at the shutter speed of step S2.

In FIG. 10, the camera 1 operates in the state of FIG.
9 is a display example after a defect is found in the measurement result at that time by the process as shown in FIG. 8. Since 1/4000 of the shutter speed selected in FIG. 9 cannot be used, 1/3200 of the safe shutter time, which is 1/3 step longer than that, is selected in step S4, and display is performed by the segment 43. Further, the aperture value resulting from the recalculation in step S6 is displayed in the segment 44. Further, in step S5, a warning that the aperture value is not the original shutter speed is issued in the segment 45.

FIG. 11 shows an embodiment to which the present invention is applied when a camera having a shutter dial is used in the manual mode. The shutter dial 46 can be manually set to any shutter speed. Shutter dial 46
Turn and turn the desired value printed on it to the indicator 47.
It should match with. In the figure, 1/4 indicated by reference numeral 49
000 seconds is selected. Further, on both sides of the reference numeral 49, 1/2000 seconds and 1/800 indicated by reference numerals 48 and 50 are given.
0 seconds is printed. However, the shutter dial 46
Even if 1/4000 seconds is selected in step S3, if it is determined in step S3 that there is a problem in the past, the control is not performed in 1/4000 seconds, so segment 45 is displayed on LCD 34 and a warning is given.

In the above embodiment, the warning judgment is executed by one measurement, but it may be executed based on the operation result of plural times. Further, in the above embodiments, since the detection device 37 is composed of the photointerrupter composed of the light emitting diode and the phototransistor, the detection can be facilitated by the electric control. A detection device such as the detection device according to 1. may be adopted. Further, in the present embodiment, when the shutter speed is determined to be defective, the next control is 1
An example of replacing at a shutter speed of 3 steps longer was shown.
It does not have to be limited to three stages.

[0034]

As described above in detail, according to the present invention, the actual exposure time by the shutter is compared with the control shutter (exposure) time to judge whether the shutter control is performed correctly, and it is not correct. In this case, the control is not performed thereafter with the shutter time or a shutter time shorter than the shutter time, so that it is possible to avoid a shooting error such that the shutter cannot be exposed at all due to defective shutter operation. If the method of correcting the next control shutter time by the difference between the actual exposure time and the control shutter time is adopted, there is theoretically no limit in the direction of increasing the shutter time, and there is a problem if the control shutter time is corrected by the above difference. However, regarding the direction of shortening, especially when the control shutter time is shortened and corrected at high shutter speed, if the operating environment after correction or mechanical system operation deterioration occurs, the shutter operates without exposure at all. The phenomenon may occur. On the other hand, by prohibiting the shutter operation in the direction of shortening the shutter time as in the present invention, it is possible to effectively avoid a shooting error due to a defective shutter operation. Since the limit shutter time can be set finely by using the posture of the camera or the temperature condition as a parameter, fine control can be performed according to the characteristics of the shutter. In other words, even if the shutter operation at a specific shutter time under a specific posture or temperature condition is poor, there is still a possibility that shooting can be performed with a shutter time that is determined to be defective under a different posture or different temperature condition. This improves the usability of the camera.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a complaint.

FIG. 2 is an external view of a camera having a shutter measuring device according to the present invention.

FIG. 3 is an example of an electric circuit block diagram of the camera.

FIG. 4 is a diagram showing an embodiment of a shutter traveling state detection device of the camera.

FIG. 5 is an example of a timing chart of the shutter measuring device.

FIG. 6 is an example of a main processing program of a control CPU.

FIG. 7 is an example of a shutter control processing program of a control CPU.

8 is an example of a shutter control processing program following FIG.

9 is a diagram showing a display example of LCD 34. FIG.

FIG. 10 is a diagram showing another display example of the LCD 34.

11 is a diagram showing another display example of the manual dial and LCD 34. FIG.

[Explanation of symbols]

 1 Camera 8 Shutter 15 Front Curtain 16 Rear Curtain 18 LED 19 PTR 20, 21 Slit Forming Blade 22 Normal Blade 32 CPU 37 Shutter Running State Detection Device

Claims (6)

[Claims] 1. A camera comprising a calculation means for obtaining an exposure time to be controlled, and a control means for controlling the shutter with the control exposure time obtained by the calculation means, the shutter being driven and controlled by the control means. Measuring means for measuring the obtained actual exposure time, judging means for judging whether or not the actual exposure time is within a predetermined normal operating range, and this judging means for determining whether the actual exposure time is outside the normal operating range. A camera having a shutter measurement device, comprising: a prohibition unit that prohibits shutter drive for at least the control exposure time when it is determined that there is. 2. The camera according to claim 1, wherein the prohibiting means includes a control exposure time determined by the determining means to be that the actual exposure time is not within a normal operation range, and all controls higher than that. A camera having a shutter measuring device, wherein shutter operation is prohibited during exposure time. 3. The camera according to claim 1, further comprising attitude detecting means for detecting the attitude of the camera, wherein the normal operating range is set according to the attitude of the camera detected by the attitude detecting means. A camera having a shutter measuring device. 4. The shutter measurement according to claim 1, further comprising temperature detecting means for detecting a temperature, wherein the normal operating range is set according to the temperature detected by the temperature detecting means. Camera with a device. 5. The camera according to claim 1, wherein the prohibiting unit includes a resetting unit that sets a new control exposure time on a lower speed side than the control exposure time determined not to be within the normal operating range, A camera having a shutter measuring device, wherein the control means drives and controls a shutter with a newly set control exposure time. 6. The camera according to claim 1, further comprising a recalculation unit that recalculates an aperture value based on the control exposure time set by the resetting unit.