JPH0850314A - Continuous luminance measuring apparatus of camera and its control method - Google Patents

Abstract

PURPOSE: To provide a continuous luminance measuring device capable of obtaining suitable exposure even when the luminance, of a subject is changed and obtaining a fine picture and its controlling method. CONSTITUTION: This device is provided with a release one-step switch S1 and a release two-step switch S2 to be driven in accordance with a photographer's photographing selection, a photographing control part 40 for continuously measuring the luminance of a subject at a fixed time interval by outputting a photometric signal for measuring the luminance of the subject when te switch S1 is driven and outputting a photometric signal for measuring the lumiannce of the subject when the switch S2 is not driven within fixed time, and when the switch S2 is driven, computing the quantity of exposure based on the quantity of finally measured luminance, and a luminance photometry part 20 for measuring the brightness of the subject in accordance with the photometric signal outputted to the control part 40 and outputting a signal corresponding to the brightness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous brightness measuring apparatus for a camera and a control method thereof. More specifically, the present invention relates to a technique for continuously measuring the brightness of a subject and controlling exposure according to the shutter release 1-step switch being operated and the release 2-step switch not being operated even after a certain period of time has elapsed.

[0002]

2. Description of the Related Art In a conventional brightness measuring device for a camera, when a photographer presses a shutter button to photograph a subject, a release 1-step switch is operated, and then a release 2
The step switch is activated.

When the release one-step switch is actuated, the automatic distance measuring unit of the camera measures the distance to the subject and the brightness photometry unit measures the brightness of the subject. The microcontroller calculates an appropriate exposure value from the brightness of the subject measured by the brightness photometry unit, and when the release two-stage switch is operated, the shutter is operated according to the exposure value to take a picture.

In such a camera brightness measuring device, the brightness of the subject is measured only when the release first-stage switch is operated, and the exposure of the shutter is controlled according to the measured value.

[0005]

However, if the position and orientation of the subject changes between the actuation of the first release switch and the actuation of the second release switch, the brightness of the subject changes.

Therefore, when the release two-step switch is operated, even if the brightness of the subject changes, the shutter is operated by the exposure value calculated from the brightness value measured first, and the brightness of the subject is changed. There is a problem that the proper exposure cannot be performed according to the above.

An object of the present invention is to continuously measure the brightness of an object when the release two-step switch is not operated within a fixed time after the release one-step switch is operated.
The exposure value is calculated from the brightness value measured before the release two-step switch is operated, and the shutter is controlled to improve the product reliability, and a continuous brightness measurement of the camera is obtained to obtain a photograph with a clear and accurate exposure value. An object is to provide an apparatus and a control method thereof.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a release 1-step switch and a release 2-step switch which are operated in accordance with a photographer's shooting selection, and an operation of the release 1-step switch. Sometimes it outputs a photometric signal to measure the brightness of the subject, and when the release two-step switch is not activated within a certain time, it outputs a photometric signal to measure the brightness of the subject to set the brightness of the subject at regular intervals. And the brightness of the subject according to the photometric signal output to the shooting control unit, which calculates the exposure amount based on the brightness amount that is finally measured when the release two-stage switch is operated. Provided is a continuous luminance measuring device for a camera, which has a luminance photometry unit for measuring a height and outputting a signal corresponding to the height.

Also, after power is applied to the camera, a step of initializing all operating circuits and use variables to determine whether or not to operate the release first-stage switch, and the step of operating the release first-stage switch When measuring the brightness of the subject, it is judged whether the release two-step switch has been actuated. If the release two-step switch has not been actuated, it is judged whether a certain time has passed. In addition, the step of continuously measuring the brightness of the subject at a constant time interval, and the release 2 when the release 2-step switch is operated.
A continuous brightness measurement method for a camera is also provided, comprising the step of computing the exposure of the camera according to the last measured brightness before the step switch is activated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a continuous luminance measuring apparatus for a camera according to an embodiment of the present invention, FIG. 2 is a detailed circuit diagram of a luminance photometry unit of a continuous luminance measuring apparatus for a camera according to an embodiment of the present invention, and FIG. FIG. 4 is a charging graph of the capacitor of the brightness photometry unit according to the embodiment of the present invention, FIG. 4 is an operation sequence diagram of the continuous brightness photometry device of the camera according to the embodiment of the present invention, and FIG. 5 is a continuous brightness measurement device of the camera according to the embodiment of the present invention. Is the operation timing.

As shown in FIG. 1, the continuous brightness measuring apparatus for a camera according to this embodiment has an automatic distance measuring section (10) for measuring the distance to the object and a brightness metering section (20) for measuring the brightness of the object. ), A film sensitivity sensing unit (30) for measuring the sensitivity of the film mounted on the camera, a release 1-step switch (S1), and a release 2-step switch (S).
2), the automatic distance measuring unit (10) and the brightness photometric unit (2
0), and a photographing control unit (40) for controlling a photographing operation according to a signal input by being connected to an output stage of the film sensitivity sensing unit (30) and the switches (S1, S2), and the photographing control unit (40). Shutter section (50) connected to the output stage of the motor, a motor drive section (60), and an information display section (7).
0) and.

As shown in FIG. 2, in the configuration of the brightness photometry unit (20) according to the embodiment of the present invention, one side terminal is connected to the power source (C1) and the emitter terminal is connected to the power source. A transistor (T1) whose collector terminal is connected to the base terminal of the transistor (T1), the base terminal of which is connected to the output terminal of the photographing control unit (40), and whose emitter terminal is grounded. Have.

Further, one terminal is connected to the transistor (T
1) a resistor (R1) connected to the collector terminal, a resistor (R2) whose one side terminal is connected to the other side terminal of the resistor (R1) and whose other side terminal is grounded, and one side terminal The photoconductive cell (cds) connected to the collector terminal of the transistor (T1) and one side terminal of the transistor (T1).
1) A variable resistor (VR) connected to the collector terminal and the other terminal connected to the other terminal of the photoconductive cell (cds).
1), a resistor (R3) whose one side terminal is connected to the other side terminal of the photoconductive cell (cds), and one side terminal which is connected to the other side terminal of the resistor (R3) and grounded on the other side Has a capacitor (C2) that is grounded.

Further, a comparator (IC1) having a non-inverting terminal connected to the other terminal of the resistor (R3) and an inverting terminal connected to the other terminal of the resistor (R1) and a collector terminal of the comparator (IC1). Transistor (T3) having a base terminal connected to the non-inverting terminal of the device (IC1), a base terminal connected to the collector terminal of the transistor (T2), and an emitter terminal grounded, and one side terminal of which is the collector of the transistor (T1). A resistor (R4) connected to the terminal and having the other terminal connected to the output stage of the comparator.

In the above structure, the comparator (IC1)
The output terminal of is connected to the input terminal (IN) of the imaging control unit (40). The operation of the continuous luminance measuring device for a camera according to the embodiment of the present invention having the above-described structure will be described below.

When power is applied to the camera, the photographing control section (40) initializes all operating circuits, used variables, and internal timer (S110), and the release first-stage switch (S1) operates. It is determined whether or not (S12
0).

When a photographer presses a shutter button (not shown) to photograph a subject, the release first-stage switch (S1) operates and an electric signal corresponding thereto is sent to the photographing control section (40). Entered in.

The photographing control section (40) has the release 1
When the stage switch (S1) is operated, the voltage state and the charging state of the strobe (not shown) are checked (13).
0). Further, the sensitivity of the film mounted on the camera is measured (S140). The film sensitivity detector (30)
Senses the sensitivity of the film to be mounted and outputs an electrical signal corresponding to it to the photographing control section (40).

After performing the above operation, the photographing control unit (4
0) is a brightness metering unit (2) for measuring the brightness of the subject.
0) is driven. The photographing control unit (40) outputs a drive signal (OUT) from the low state to the high state to drive the brightness photometry unit (20) (S150).

The photographing control section (40) activates and outputs a drive signal (OUT) for driving the brightness metering section (20), and then activates an internal timer (not shown) to perform the brightness metering. The time until the high level signal is output to the unit (20) is counted.

The high level drive signal (OUT) output from the photographing control section (40) is supplied to the luminance photometry section (20).
The transistor (T2) is turned on by being applied to the base terminal of the transistor (T2).

When the transistor (T2) is turned on, the potential of the connector terminal changes to the low state, and the low signal is applied to the base terminals of the transistor (T1) and the transistor (T3). The transistor (T
A low signal is applied to the base terminal of 1) to turn on the transistor (T1) and turn on the transistor (T3).

Since the transistor (T1) is turned on and power is applied, the brightness metering unit (20) operates as follows.
Measure the brightness of the subject. The voltage applied to the brightness photometry unit (20) sets a reference voltage at the inverting terminal of the comparator (IC1) according to the resistance (R2) value of the resistor (R1), and the reference voltage is set through the transistor (T1). The applied voltage charges the capacitor (C2) with the resistance value of the photoconductive cell (cds).

The resistance value of the photoconductive cell (cds) changes according to the brightness of the subject, and the photoconductive cell (cds)
The charging rate of the capacitor (C2) changes according to the resistance value of (s). The charging rate of the capacitor according to the embodiment of the present invention is as shown in the attached FIG.

When the charging voltage of the capacitor (C2) rises and the voltage applied to the non-inverting terminal of the comparator (IC1) becomes larger than the voltage applied to the inverting terminal, the output value of the comparator (IC1). Changes from low level to high level and is output to the photographing control section (40).

The output terminal (I
When a high level signal is output to (N), the imaging control unit (4
0) judges the brightness state of the subject by detecting the count number of the timer. When the detected count number is less than or equal to the first set value for determining high brightness, it is determined that the brightness of the subject is high brightness. In addition, when it is equal to or higher than the second set value for determining low brightness, it is determined to be low brightness.

In the embodiment of the present invention, the photographing control section (40) judges that the read count is high when the count is 8 or less, and the brightness is low when the count is 80 or more. It is determined that As shown in FIG. 3, the curve A according to the charging speed of the capacitor according to the brightness of the subject.
Indicates high brightness, and the curve C indicates low brightness.

When it is determined that the brightness of the current subject is low and the measured count number is equal to or greater than the second set value, the photographing control section (40) causes the information display section (70).
To warn the photographer that the brightness is low. Then, the imaging control unit (40) sets the shutter speed to the minimum (S180 to S190).

When the brightness of the current subject is not low luminance, it is determined to be high luminance, and when the measured count number is less than or equal to the first set value, the shutter speed is set to the maximum. (S200-210).

When the measured count number is between the first set value and the second set value and neither low brightness nor high brightness is determined, the automatic exposure program is driven according to the measured count number to set the shutter speed. (Ev ← Sv + Lv)
Is set (S220).

After setting the shutter speed according to the measured brightness of the subject, the photographing control unit (40) drives the automatic distance measuring unit (10) to measure the distance to the subject, and according to the measured distance. Automatic distance calculation (S230-S
240).

After performing the automatic distance calculation, the photographing control unit (40) determines whether or not the release two-step switch is operated (S250). If the release two-step switch is not operated, a certain period of time elapses. It is determined whether or not (S260).

If the photographer does not press down the shutter button accurately and a certain period of time elapses without operating the release two-stage switch, the photographing control section (40)
Activates a signal for driving the brightness metering unit (20) in order to measure the brightness change according to the position of the subject and the camera composition change (S150).

If the release two-step switch (S2) is not operated within a fixed time, the brightness of the subject is continuously measured as described above, and then the brightness measured immediately before the release two-step switch is operated. The exposure amount is calculated based on the value.

When the release two-step switch is operated as described above, the photographing control section (40) drives the shutter section (50) according to the calculated exposure amount and shutter speed (S260) to obtain the desired value. The subject (S27)
0). After the film of one frame is photographed as described above, the motor driving unit (60) is driven to feed the film, and the operation is completed (280 to S290).

[0037]

As described above, according to the present invention, the release first-stage switch is operated by the photographer's depression of the shutter button to measure the brightness of the subject, and the release second-stage switch is operated within a certain period of time. If not, the brightness of the subject is continuously measured. Therefore, even if the position of the subject or the drive of the camera changes before the release 2-step switch is activated, the exposure is properly adjusted according to the change in the brightness of the subject. You can take a picture of it.

Further, even in an optical measuring device other than the camera, the luminance of a moving subject is accurately measured, so that the photograph can be accurately exposed and the reliability of the product can be improved at a low cost.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a continuous luminance measuring device for a camera according to an embodiment of the present invention.

FIG. 2 is a detailed circuit diagram of a luminance measuring unit in the continuous luminance measuring device for the camera according to the embodiment of the present invention.

FIG. 3 is a charging graph of a capacitor of a luminance photometry unit according to an embodiment of the present invention.

FIG. 4 is an operational sequence chart of the continuous luminance photometric device of the camera according to the embodiment of the present invention.

FIG. 5 is an operation timing chart of the continuous luminance measuring device of the camera according to the embodiment of the present invention.

[Explanation of symbols]

 10 ... Automatic distance measuring unit 20 ... Luminance photometric unit 30 ... Film sensitivity detector 40 ... Shooting control unit 50 ... Shutter unit 60 ... Motor drive unit 70 ... Information display unit

Claims (6)

[Claims] 1. A release one-step switch and a release two-step switch that are operated according to a photographer's shooting selection, and a photometric signal for measuring the brightness of an object when the release one-step switch is operated, and which is constant. When the release 2-step switch is not activated within the time, a photometric signal for measuring the subject brightness is output to continuously measure the brightness of the subject at fixed time intervals, and when the release 2-step switch is activated, the final And a brightness metering unit that measures the brightness of the subject according to the photometric signal output to the shooting controller and outputs a corresponding signal. A continuous brightness measuring device for a camera. 2. An automatic distance measuring section for measuring a distance to a subject and outputting a signal corresponding thereto, and a film sensitivity detecting section for sensing a sensitivity of a film mounted on a camera and outputting a corresponding signal. , A shutter part that exposes the film mounted on the camera, a motor drive part that transports the film to be shot, and information that warns the photographer that the brightness is low when the brightness of the subject is low. The continuous luminance measuring device for a camera according to claim 1, further comprising a display unit. 3. The photographing control section senses film sensitivity when a release one-step switch is operated to measure a distance to the object, and then shutters when the measured object has a low brightness. Set the speed to the minimum, set the shutter speed to the maximum when the brightness is high, and set the exposure amount according to the distance of the object and the measured brightness when the brightness of the subject is neither low nor high. 3. When the release two-stage switch is actuated, the shutter section is operated according to the exposure amount set to photograph an object, and a signal for transferring the film to be photographed is output. Continuous brightness measurement device for camera. 4. The photographing control section outputs a signal for measuring the luminance of a subject to the luminance photometry section and then activates a timer to count the time until the high signal is outputted from the luminance photometry section. The continuous brightness measuring device for a camera according to claim 3, wherein the brightness of the object is obtained according to the counted value. 5. A step of initializing all operating circuits and use variables to determine whether or not to operate a release one-step switch after power is applied to the camera, and when the release one-step switch is operated. The step of measuring the brightness of the subject, and whether the release two-step switch is activated,
When the release two-step switch is not operated, it is determined whether or not a certain period of time has elapsed, and when the certain period of time has elapsed, the brightness of the subject is continuously measured at intervals of a certain period of time. A continuous luminance measuring method for a camera, comprising the step of calculating an exposure amount of the camera according to a luminance amount measured last before the release two-stage switch is activated, when the two-stage switch is activated. 6. A step of measuring the distance to the object by sensing the film sensitivity after the release one-step switch is operated, and measuring the amount of brightness of the object. When the brightness is low, the shutter speed is minimized. Set the shutter speed to the maximum when the brightness is high, and set the exposure amount according to the measured brightness when the brightness is neither low nor high, and the release two-step switch is activated. After taking a picture by driving the shutter part according to the exposure amount set above,
6. The continuous brightness measuring method for a camera according to claim 5, further comprising the step of transferring the filmed film by one frame.