JP3344052B2 - Camera with shutter measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a shutter measuring device for detecting a running state of a shutter used in the camera.

[0002]

2. Description of the Related Art Conventionally, in a camera, a light beam from a subject is limited by a lens aperture, and an exposure time to a film is limited by a mechanical shutter. A shutter used in a single-lens reflex camera basically includes two curtains of a front curtain and a rear curtain, and the exposure is obtained by controlling the opening and closing of their operations temporally. In the past, these operations were controlled purely mechanically, but in recent years, electrical control has been increasingly used. The traveling of the front curtain and the rear curtain itself still uses the spring force,
The start control of the running is performed by energizing the electromagnet which locks the curtain.

[0003] On the other hand, increasing the speed of the shutter, such as 1/8000 second, is becoming an important specification, and it is also necessary to increase the tuning speed so that image formation in a bright environment using a strobe can be performed. For this purpose, it is necessary to increase the above-mentioned spring force so as to increase the traveling speed of each curtain dramatically, and to control the slit width formed by the front curtain and the rear curtain during traveling to be narrow.

However, no matter how precisely the energization control timing of the electromagnet is controlled, the exposure time actually obtained on the film surface depends on the mechanical running state of each curtain as in the conventional case. Variation factors include variations in the release speed of the locking mechanism with respect to the electromagnet, friction of the mechanical traveling system including the spring, and the like. Further, it has a temperature characteristic and a variation characteristic due to a change with time, so that it is known that it shows various changes comprehensively.

[0005]

For example, the shutter priority mode is a mode in which an aperture value is calculated based on a manually selected shutter time and both are operated to obtain an appropriate exposure. The nominal value and the true shutter time (control value) controlled by the nominal value may be different for the reasons described above.

In the conventional camera, the calculation and control are controlled by nominal values, so that a correct exposure result cannot be obtained.
That is, in the above example, since the aperture value is arithmetically controlled based on the nominal value of the shutter time, there is a problem that the exposure amount is over or under by the difference between the nominal value and the control value.

The present invention has been made in view of such a situation, and controls or displays the subsequent shutter time based on the actual shutter time measured by the measuring means, so that the correct exposure amount or It is an object of the present invention to provide a camera having a shutter measurement device capable of displaying images correctly.

[0008]

To achieve the above object, the present invention provides a mode setting means for selectively setting a plurality of exposure modes, a condition setting means for arbitrarily setting exposure conditions, Calculating means for determining an appropriate exposure condition in the determined exposure mode; display means for displaying the exposure condition; shutter driving means for driving a shutter at a shutter time value corresponding to the appropriate exposure condition determined by the calculating means; Measuring means for measuring an actual shutter time obtained by driving the means, and associating the actual shutter time obtained by the measuring means with a shutter time value, and controlling exposure conditions or display for obtaining based on the association. A control means for changing exposure conditions for each selected exposure mode is provided.

[0009]

In the camera having the above-described shutter measuring device, the control means is provided, and the calculating means is controlled so as to perform the exposure calculation based on the actual shutter time obtained by the measuring means. Based on the actual shutter time measured in step (1), control or display relating to the subsequent shutter time can be performed, and correct exposure amount or correct display can be performed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a camera having a shutter measuring device according to the present invention.

FIG. 1 shows a state in which the back cover 4 is opened. A film cartridge (not shown) is loaded in a cartridge chamber 5, and a film drawn from the cartridge passes through the front surface of an aperture 6 and is wound around a spool 7. Can be A pressure plate 9 provided inside the back cover 4 functions to press a film (not shown) against the aperture 6 to maintain flatness. A shutter 8 to be described later is provided inside the aperture 6.
As shown by a dashed line in the figure, it covers a slightly wider area than the aperture 6, and guides the subject light through the lens 2 onto the film screen for a predetermined time. The photographer visually recognizes the situation of the subject passing through the lens 2 from the viewfinder 3 and instructs the start of exposure by pressing the release button 10.

[0013] The exposure mode and various conditions are controlled by an LCD (liquid crystal).
It can be confirmed at 12. The plurality of setting buttons 11 are operation buttons for arbitrarily setting an exposure mode, a photographing condition, and the like of the camera 1, and are operated while checking characters on the LCD 12.

FIG. 2 shows an embodiment of the shutter 8 used in the present invention. A description will be given by extracting only the positional relationship between the shutter 8 and the aperture 6 in the camera 1 of FIG.

FIG. 2 shows a state before the release button 10 is pressed, that is, before the start of exposure. The aperture 6 indicated by a broken line is covered with the front curtain 15. The front curtain 15 is generally composed of a plurality of blades. As shown in FIG. 2, the front curtain 15 is composed of, for example, four blades, and when the front curtain 15 is covered with the aperture 6, the front curtain 15 is widened leaving a small overlapping portion as shown. The uppermost blade 20 in the drawing in the front curtain 15 is a blade forming a slit.

Similarly, the rear curtain 16 also includes a plurality of blades. In the state shown in FIG. The foremost blade 21 in the rear curtain 16 is a blade forming a slit, and the front curtain slit forming blade 2 described above is formed.
Cooperates with 0 to form a slit to expose the film to the desired shutter time. The block 17 is a drive unit that houses a front curtain magnet and a rear curtain magnet, which are described in detail in the electric circuit of FIG. 3, and a running spring and the like. It has a known mechanism such as an electromagnet and two systems of springs for running each curtain, and a link mechanism for moving each blade up and down in parallel.

The exposure operation from the state as shown in FIG. 2 is performed as follows.

First, a front curtain magnet (not shown) opens the front curtain 15. Thereby, the front curtain 15 is retracted so as to be folded below the aperture 6 (downward in the figure). At this time,
The slit forming blade 20 is retracted so as to be the last. Now there is nothing in the aperture 6 that blocks the subject light,
Exposure to the film will begin. After a lapse of a predetermined time, a rear curtain magnet (not shown) opens the rear curtain 16. Then, the rear curtain 16 moves downward from the illustrated position so as to spread with respect to the aperture 6. At this time, the slit forming blade 21 moves so as to be the leading in the trailing blade.
The aperture 6 is now covered by the second curtain 15
Exposure at the scheduled time is completed.

After the exposure is performed as described above, the film is fed by one frame by a winding mechanism (not shown), and a new unexposed portion of the film faces the aperture 6 and each of the curtains 15 and 16 is moved. Are respectively lifted upward to return to the state before exposure.

On the other hand, the LE 8 according to the present invention is provided in the shutter 8.
A detection means 37 by a D (light emitting diode) 18 and a PTR (phototransistor) 19 is used for the rear curtain 15 and the front curtain 1
6 are provided so as to face each other near the tip of each blade. The light from the LED 18 is transmitted to the front curtain 15 or the rear curtain 15.
Is present at that position, it is reflected by those vanes and PT
It is incident on R19. Conversely, if each blade does not exist,
That is, there is no light incident on the PTR 19 during the exposure. Therefore, if the output of the PTR 19 is determined, it is possible to detect the presence or absence of light incident on the PTR 19, that is, the actual exposure time.

FIG. 3 is an example of a time chart showing the relationship between the operation sequence of the camera 1 and the operation of the shutter 8. FIG.
5 shows a running state of each curtain and a change in the output signal of the PTR 19, which change depending on the on / off timing of the magnet (MG) for controlling each curtain.

When the release button 10 is pressed, the leading and trailing curtain magnets are energized and turned on, and the electrical locking of each curtain starts. Before the release button 10 is depressed, the mechanical locking has been performed, but the control is now switched to electric control. Then, by a mechanism operation not shown,
First, the aperture control of the lens 2 is executed, and the reflection mirror in the photographing optical path is raised. Next, the front curtain magnet is turned off. As a result, the front curtain 15 travels as indicated by the travel curve f. Here, a range of F indicated by a broken line indicates a vertical opening of the aperture 6, and a running curve f indicates a state in which the vehicle travels in the opening F with a locus as illustrated. At this time, since the slit forming blades 20 of the front curtain 15 pass through the front surface of the detecting means 37 during the traveling, the output of the PTR 19 is inverted at the timing of 22 in the figure in the middle of the traveling curve f.

Thereafter, the trailing curtain magnet is turned off after the elapse of a preset exposure time T.
As a result, the rear curtain 16 crosses the opening F as indicated by the running curve r.
Also at this time, since the rear curtain 16 passes through the front of the detection means 37,
In the middle of the running curve r, the output of the PTR 19 is inverted at the timing of 23 and returns to the original state.

As described above, if the reversal time of the PTR 19 is measured in accordance with the operation timing of each magnet, it is possible to know that the true exposure time is t.

FIG. 4 is a block diagram showing an electric circuit of the camera 1 for controlling the above operation. This circuit is battery 2
5 is used as a power source, and the central control is executed by the CPU 32. C
The input signals to the PU 32 are as follows.

First, the photometric means 26 is a known sensor means comprising a photodiode for measuring the brightness of each part obtained by dividing the subject into a plurality of parts.
It is input to U32. The film sensitivity detecting means 27 reads a code signal given to the side of the loaded film cartridge and the like.
32. The switch detecting unit 28 includes a manual switch including a switch linked to 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.
All state information of the camera is input to the CPU 32.

The output from the CPU 32 is supplied to the driver 3
3, the following drive is executed. The LCD 12 is driven to display information on exposure and operation mode setting, warning information, and the like. The operation time interval of the shutter 8, more specifically, the first curtain magnet and the second curtain magnet, that is, the exposure time T
Control. The stop 35 in the lens 2 is driven to control the amount of transmitted light. Drive the motor 36 to wind up the film,
The rewinding feeding and the urging operation of the shutter driving spring are controlled. By controlling the detection means 37, the LED 18 is turned on for a required time, and the signal generated from the PTR 19 is
PU32 accepts.

FIG. 5 is a flowchart showing a processing routine by the CPU 32 in FIG. This routine is repeatedly executed while power is supplied.

In step S1, photometric signals and sensitivity signals from the photometric means 26 and the sensitivity detecting means 27 are fetched, respectively. In step S2, both are calculated based on the set exposure mode, and a shutter time and an aperture value, which are appropriate exposure conditions, are calculated. At the same time, a display that matches the mode is also performed. The details of the arithmetic processing will be described later with reference to FIG. In step S3, information other than the content displayed in step S2 is displayed on the LCD.
In step S4, it is determined via the switch detecting means 28 whether or not the release button 10 has been pressed. If not, the process returns to step S1 to repeat the above processing.

In step S5, the release button 1
Since 0 has been pressed, first and second curtain magnets are first turned on as described with reference to FIG. Step S6
In step (1), a reflection mirror (not shown) is raised and retracted from the photographing optical path. In step S7, the aperture 35 is controlled to have a predetermined aperture. In step S8, a shutter routine for opening and closing the shutter 8 to control exposure to the film and a shutter curtain running state detection routine by the detection means 37 are executed. As the exposure time control value in the shutter routine, the value obtained in step S2 is used. Details of the detection routine will be described later with reference to FIG. In step S9, since the exposure operation has been completed, the motor 36 is rotated forward to perform the feeding of the film and the urging operation of the mechanism. Since the exposure operation has completed one cycle, the process returns to step S1 to repeat the above processing.

FIG. 6 is a flowchart showing a shutter curtain running state detection routine in step S8.

In step S15, the shutter time T to be controlled obtained in step S2 is read. Step S
At 16, the energization of the front curtain magnet is terminated, and the traveling of the front curtain 15 is started. Thereafter, the processes starting from step S17 and step S18 are simultaneously executed. For ease of explanation, the case where the control time T in this embodiment is sufficiently longer than each curtain running time is described as an example. When the control time T is extremely short, it is necessary to manage timekeeping and measurement by a known method such as interrupt processing.

In step S17, counting of the control time T is started. In step S18, step S1
At the same time as 7, the lighting of the LED 18 is started. Step S1
At 9, the process waits for the output of the PTR 19 to be inverted by the start of passage of the front curtain 15. This corresponds to the timing 22 in FIG.
Is equivalent to In step S20, the counting of the measuring time t is started.

In step S21, the control waits for the completion of the counting of the control time T. In step S22, since the control time T has been completed, the energization of the rear curtain magnet is terminated, and the rear curtain 1
6 is started. In step S23, it waits for the output of the PTR 19 to be inverted by the start of passage of the rear curtain 16. This corresponds to the timing 23 in FIG. In step S24, the time measurement is completed, and the time measurement time t is obtained. In step S25, since the measurement has been completed, LE
D18 is turned off. In step S26, the measured time t is stored in a table indicating the correspondence between the nominal value and the control time described later.

Table 1 is an example of a table showing the relationship between the nominal value of the shutter time stored in the memory in the CPU 32 and the control value.

[Table 1]

Although Table 1 shows values for each step for ease of explanation, it is assumed that the values are actually prepared for every several steps. Here, the nominal value is, for example, a shutter time value that is arbitrarily selected by operating the setting button 11 when the manual mode is set.
The control value is a value of the measurement time t actually obtained when the nominal value is applied as it is to the control time T in FIG. 6 and controlled. Therefore, the nominal value and the control value are often very small but different.

In the example shown in Table 1, the result measured by the detecting means 37 in the previous exposure operation is reflected.
It is recorded that the control value is slightly shorter than the nominal value for 00 and 1/1000. Other shutter times were not selected during the exposure operation, so the nominal value recorded from the beginning remains the same, or even if the shutter time was selected, the result of the detecting means 37 coincided with the nominal value, so it remains as it is. This is an example.

FIG. 7 is a flowchart showing an arithmetic processing routine of step S2 (FIG. 5). Here, basic arithmetic expressions in the exposure control of the camera will be described first.

The subject brightness is BV, the film sensitivity is SV,
Assuming that the shutter time is TV and the aperture value is AV, the condition for proper exposure must satisfy the following expression.

BV + SV = TV + AV (1)

In FIG. 7, V in Equation 1 is omitted to simplify the description.

In step S25, the setting button 11
The exposure mode selected in is determined. There are four types of exposure modes: manual (M), shutter priority (S), aperture priority (A), and program (P). In the manual (M) mode, step S26 and shutter priority (S ) Mode, the processing from step S31 is performed in the aperture priority (A) mode, and the processing from step S39 is performed in the program (P) mode.

In the case of the manual mode (M), the nominal value of the shutter time selected by the setting button 11 is read in step S26. In step S27, the aperture value similarly selected by the setting button 11 is read. In step S28, a control value is obtained from the nominal value of the shutter time based on Table 1. In step S29, the sum (tV) of the appropriate exposure condition determined by BV + SV in equation 1, the selected control value tV, and the selected AV
+ AV) to determine a shift amount △ ′. If there is no difference between the control value of the shutter time and the nominal value

△ = (BV + SV) − (TV + AV), but △ 'is obtained from the actual operating conditions.

In step S30, the TV, A
V, △ 'are displayed on the LCD 12. Since the shutter time selected by the photographer is the nominal TV, the display is performed using the TV instead of the control value tV, but the actual exposure shift amount △ ′ is required to faithfully reflect the intention of drawing.

In the case of the shutter priority mode (S), the nominal value of the shutter time selected by the setting button 11 is read in step S31. In step S32, a control value t is obtained from the nominal value T of the shutter time based on Table 1. In step S33, an appropriate aperture value AV 'is obtained from the following equation obtained by modifying equation 1.

AV '= (BV + SV) -tV

In step S34, the TV, A
V ′ is displayed on the LCD 12. Since the shutter time selected by the photographer is the nominal TV, the display is performed by the TV instead of the tV, but it is more convenient for the photographer to display the value AV ′ that is actually controlled for the aperture value. .

In the case of the aperture priority mode (A), step S
At 35, the aperture value selected by the setting button 11 is read. In step S36, an appropriate shutter time tV is obtained from the following equation obtained by modifying equation 1.

TV = (BV + SV) -AV

In step S37, a nominal value TV 'closest to the shutter time control value tV obtained above is obtained based on Table 1. In step S38, the T
V ′ and AV are displayed on the LCD 12. For the shutter time, it is more convenient for the photographer to display a value TV ′ that is actually controlled.

In the case of the program mode (P), nominal TV and AV are obtained from equation 1 in step S39. In step S40, a control value t is determined from the nominal shutter speed TV based on Table 1,
An aperture value AV ′ which is equivalent to + AV is calculated.
In step S41, a nominal value TV 'closest to the shutter time control value tV determined above is determined based on Table 1. In step S42, the TV ', AV'
Is displayed on the LCD 12.

FIG. 8 is a front view showing an example in which all the segments prepared on the LCD 12 are turned on. Segment 4
0 indicates one of the exposure modes selected by the setting button 11, that is, the manual mode (M), the shutter priority mode (S), the aperture priority mode (A), and the program mode (P). The segment 41 is a manually selected or automatically set shutter time TV or T
V 'is displayed. The segment 42 displays the manually selected or automatically selected aperture value AV or AV '. The segment 43 displays the shift amount △ ′ in the manual mode.

As described above, in the manual mode, the exposure deviation amount display is corrected based on the actual shutter time, and in the shutter priority mode, the aperture value to be controlled is corrected based on the actual shutter time. In the mode, the shutter time to be controlled is corrected based on the actual shutter time, and in the program mode, both the shutter time to be controlled and the aperture value are corrected based on the actual shutter time. Further, the control means performs the display with a numerical value based on the actual shutter time.

As a result, in the manual mode, the exposure deviation amount display is corrected based on the actual shutter time, in the shutter priority mode, the aperture value to be controlled is corrected based on the actual shutter time, and in the aperture priority mode, the actual aperture value is corrected. Since the shutter time to be controlled is corrected based on the shutter time, and both the shutter time and the aperture value to be controlled are corrected based on the actual shutter time in the program mode, it is possible to always obtain a correct exposure amount. Become. Further, since the control means displays the exposure condition using a numerical value based on the actual shutter time, the photographer can recognize the actual operation condition.

In the embodiment, an example in which the exposure condition is displayed on the LCD of the camera body is shown. However, by adding a well-known data output function, the exposure condition can be provided on an accessory such as a data bag attached to the camera. It is easy to perform the same function with the provided LCD. In particular, in the case of data back, not only display but also imprint recording of the actual shutter time can be achieved at the same time.

In this embodiment, the correction is performed by one measurement. However, the correction may be performed based on a plurality of operation results.

Further, since the detecting means is an optical detecting means including a light emitting means and a light receiving means, detection can be easily performed by electrical control. However, other than this method, a magnetic detecting means or a detecting means based on a change in capacitance is used. Such a method may be used.

[0059]

As described above, according to the present invention, the measuring means
The actual shutter time obtained in step 4 corresponds to the shutter time value
To control based on the association.
Before the selected exposure condition or display exposure condition
Since the control means to vary the serial exposure mode each as Keru setting, on the basis of the actual shutter time which is measured by the measuring means, it is possible to control or display related subsequent shutter time, more accurate exposure control or By performing the detailed display , the photographer can recognize the actual operation condition .

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a camera having a shutter measuring device according to the present invention.

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

FIG. 3 is a timing chart showing an embodiment of a camera having a shutter measuring device according to the present invention.

FIG. 4 is a block diagram showing an embodiment of a camera having a shutter measuring device according to the present invention.

FIG. 5 is a flowchart showing an embodiment of a camera having a shutter measuring device according to the present invention.

FIG. 6 is a flowchart showing an embodiment of a camera having a shutter measurement device according to the present invention.

FIG. 7 is a flowchart showing an embodiment of a camera having a shutter measurement device according to the present invention.

FIG. 8 is a front view showing an embodiment of a camera having a shutter measuring device according to the present invention.

[Explanation of symbols]

 1 Camera 8 Shutter 12 Display LCD 15 Rear Curtain 16 Front Curtain 18 LED 19 PTR 37 Shutter running state detecting means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-199438 (JP, A) JP-A-1-263626 (JP, A) JP-A-4-31128 (JP, U) JP-A-54-128 28437 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B ^7/ 00-7/28 G03B 17/18 G03B 43/02

Claims (9)

(57) [Claims] 1. A mode in which a plurality of exposure modes can be selectively set.
And over de setting means, and it can be arbitrarily set condition setting means exposure conditions, and calculating means for calculating a proper exposure condition definitive to the selected Exposure mode, a display means for displaying the exposure conditions, by said computing means Shutter driving means for driving a shutter with a shutter time value according to the obtained appropriate exposure condition ; measuring means for measuring an actual shutter time obtained by driving the driving means; and The obtained actual shutter time is
Data, and based on the
Control exposure conditions or display exposure conditions
And a control means for changing the exposure mode for each of the selected exposure modes . 2. When the exposure mode is a manual mode , the calculating means sets a previous time based on the actual shutter time.
The camera having the shutter measuring device according to claim 1, wherein an exposure shift amount from the appropriate exposure condition is calculated. 3. A camera having a shutter measuring device according to claim 2, wherein said exposure deviation calculated by said calculation is displayed on said display means. 4. When the exposure mode is a shutter priority mode ,
The shutter time value set by the condition setting means.
The proper exposure on the basis of the actual shutter time corresponding to
The camera having the shutter measurement device according to claim 1, wherein the calculation unit calculates an aperture value equivalent to a light condition . 5. An equivalent aperture value calculated by said calculating means,
With the shutter time value set by the condition setting means
5. The camera having the shutter measuring device according to claim 4 , wherein said camera is displayed on said display means. 6. When the exposure mode is an aperture priority mode .
Is the aperture set by the arithmetic means in the condition setting means.
Find a shutter time suitable for the value
Wherein the shutter time for the closest displayed im correspondence
A camera having a shutter measuring device according to claim 1, characterized in that obtained from. 7. A camera having a shutter measuring device according to claim 6, wherein the displaying the display shutter time on the display means. If 8. The exposure mode is the program mode,
The calculating means determines the appropriate time based on the actual shutter time.
The camera according to claim 1, wherein both the aperture value equivalent to the normal exposure condition and the shutter time displayed on the display unit are calculated. 9. An equivalent aperture value calculated by said calculating means and a previous aperture value.
A camera having a shutter measuring device according to claim 8 and a serial display shutter time, and displaying on the display means.