JPH11341342A - Electronic image-pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic image-pickup device capable of obtaining a superior snapshooting property by easily obtaining correct exposure value and shortening the processing time from release start to main exposure. SOLUTION: A signal which is image picked up by a CCD 5 through a focus lens 3, etc., is inputted to an AC(auto exposure) processing circuit 13 and an AF(auto focus) processing circuit 14, through an image pickup circuit 6 and an A/D converter 7 and respectively outputs AE and AF evaluating values to a CPU 15. When the release operation of an operation SW 24 is performed, the CPU successively sets the shutter speed of an electronic element shutter in the CCD, for instance, from a high speed to a low speed based on a prescribed timing, performs respective exposures, and obtains plural exposure detection values. After that, the CPU detects an optimum exposure detection value from the exposure detection values and performs regular exposure after performing exposure for pre-photometry, based on the selected exposure detection value. Thus, it is possible to obtain accurate exposure, also to reduce processing time from release operation start to the main exposure, and to improve the snapshooting property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic imaging apparatus capable of performing photometry in a short time from the start of a release operation and capable of accurately controlling an exposure amount.

[0002]

2. Description of the Related Art In recent years, with the progress of digitization of image signal processing and advancement of image signal compression technology, an electronic image pickup device capable of digitizing a picked-up image signal and storing it in a memory has attracted attention.

In such an electronic image pickup apparatus, an image pickup signal picked up by an image pickup device can be stored in memory as digital image pickup data. Since it is possible to easily edit and display imaging data, it is very popular with users and is expected to have future demand.

In general, when an image of a subject is to be photographed using such an electronic image pickup apparatus, an accurate exposure amount of the subject must be obtained in order to accurately reproduce the subject. FIG. 6 shows an example of an automatic exposure control method conventionally implemented in an electronic imaging device such as a video camera to obtain an accurate exposure amount of a subject.

FIG. 6 shows an example of an automatic exposure control method generally used in a conventional electronic image pickup apparatus such as a video camera, and is a timing chart for explaining the automatic exposure control method.

Normally, in an electronic image pickup apparatus such as a video camera, a series of operations of correcting an aperture and a shutter speed based on a photometric value to calculate an exposure amount can finally obtain an optimal exposure amount. It has been repeated until.

More specifically, as shown in FIG. 6, for example, after a first-stage release operation is performed, a timing signal (for example, a vertical synchronization signal VD shown in FIG. 6A) is supplied first. At time t1, photometric exposure is performed to obtain an exposure value.

Thereafter, at time t2 when the next vertical synchronizing signal VD is supplied, a video signal from the image sensor at the time of this photometric exposure is read and, at the same time, the digitized image data is converted to an automatic exposure processing circuit (hereinafter, referred to as "auto exposure processing circuit"). AE processing circuit)
To perform AE processing to obtain a photometric result necessary for automatic exposure control, that is, an AE evaluation value.

Time t at which the next vertical synchronizing signal VD is supplied
In step 3, the exposure calculation operation required to obtain the optimal brightness of the subject is performed based on the AE evaluation value, and the shutter speed and the gain are reset to the obtained exposure conditions.

Thereafter, at time t4 when the next vertical synchronizing signal VD is supplied, photometric exposure is performed again under new setting conditions.

Thereafter, a series of exposure control operations based on the photometry are controlled so as to be repeatedly performed until an optimum exposure amount is finally obtained.

Thus, it is possible to obtain an accurate exposure amount for the main exposure, that is, a subject required at the time of image pickup.

However, with such a conventional exposure control method, it is possible to accurately obtain the exposure amount of the subject, but the processing time from the start of the release operation to the actual exposure (imaging) becomes long. In particular, this is an important problem in an electronic imaging apparatus that performs still photography that requires quick shooting, and the actual situation has not been solved by the conventional technology.

[0014]

As described above, in a conventional electronic imaging apparatus such as a video camera, after performing pre-photometry performed prior to main exposure, the aperture and shutter speed are adjusted based on the photometry result. An exposure control method is generally adopted in which a processing operation of correcting and calculating an exposure amount is repeatedly performed until an optimum exposure amount is finally obtained. If such a method is adopted for the electronic imaging device to be performed, the processing time from the start of the release operation to the main exposure becomes long, that is, it is not possible to take a picture in a short time, and the There is a problem that the quick-shot performance is adversely affected.

Accordingly, the present invention has been made in view of the above-mentioned problems, and is capable of obtaining an accurate exposure amount easily and shortening the processing time from the start of the release to the main exposure. It is an object of the present invention to provide an electronic imaging device capable of obtaining a property.

[0016]

According to the present invention, there is provided an electronic image pickup apparatus, comprising: an image pickup element for photoelectrically converting a subject image formed by an image pickup lens to generate a video signal; and a response to a shutter release signal. A first photometric unit for performing photometry while changing the exposure value for each screen with the aperture open, and obtaining a plurality of photometric values; and the plurality of photometric units measured by the first photometric unit. Selecting means for selecting an optimum photometric value from the values, second photometric means for performing narrowed-down photometry based on the photometric value selected by the selecting means, and based on the photometric value measured by the second photometric means. Exposure amount control means for controlling the exposure amount of the image sensor.

According to the first aspect of the present invention, a subject image formed by an image pickup lens by an image pickup device is photoelectrically converted to generate a video signal. When taking an image, a plurality of photometric values are obtained by the first photometric device while changing the exposure value for each screen with the aperture open in response to a shutter release signal, and a plurality of photometric values are obtained. The optimum photometric value is selected from the plurality of photometric values. Then
The second light metering means performs narrowing down metering based on the photometric value selected by the selecting means, and thereafter, the exposure device controls the image sensor based on the photometric value obtained by the second light metering means. Is controlled. Thereby, while being able to obtain an accurate exposure amount,
The processing time from the start of the release operation to the main exposure (at the time of imaging) can be shortened.

According to a second aspect of the present invention, there is provided an electronic image pickup apparatus, comprising: an image pickup element for photoelectrically converting a subject image formed by an image pickup lens to generate a video signal;
A video signal reading means for reading a video signal at a screen cycle of 60 seconds or 1/30 seconds; and a plurality of photometric devices which respond to a shutter release signal and perform photometry while changing an exposure value for each screen with an aperture open. First photometric means for obtaining the photometric value of the photometric value, selecting means for selecting an optimal photometric value from the plurality of photometric values measured by the first photometric means, and photometric value selected by the selecting means A second photometric unit that performs aperture-based photometry on the basis of: an exposure amount control unit that controls an exposure amount of the image sensor based on a photometric value measured by the second photometric unit; and a selection unit that is selected by the selection unit. The time interval between the timing at which the obtained photometric value was obtained and the timing of the aperture metering, and the time interval between the timing of the aperture metering and the timing of exposure by the exposure amount control means. And control means for the third integer multiple surfaces period, is obtained by including a.

According to the second aspect of the present invention, the image of the subject formed by the image pickup lens is photoelectrically converted by the image pickup element to generate a video signal, and the video signal readout means outputs 1/60 second or 1/60 second from the image pickup element. The video signal is read at a screen cycle of 30 seconds. When taking an image, a plurality of photometric values are obtained by the first photometric device while changing the exposure value for each screen with the aperture open in response to a shutter release signal, and a plurality of photometric values are obtained. The optimum photometric value is selected from the plurality of photometric values. Next, a second metering unit performs aperture metering based on the metering value selected by the selecting unit, and then, based on a metering value obtained by the second metering unit, by an exposure amount controlling unit. The exposure amount of the image sensor is controlled. At this time,
The control unit sets a time interval between the timing at which the photometric value selected by the selection unit is obtained and the timing of the aperture metering, and a time interval between the timing of the aperture metering and the timing of exposure by the exposure control unit. Control is performed at an integral multiple of 3 of the screen period. Therefore, in addition to the same operation as in the first aspect of the present invention, the timing of photometry and exposure can be controlled, so that the main exposure can be performed at the same flicker timing as that at the time of photometry, and the influence on flicker is reduced. Instead, a correct exposure can be obtained.

According to a third aspect of the present invention, in the electronic imaging apparatus according to the second aspect, between the photometry by the first photometry unit and the photometry by the second photometry unit. And performing auto-focusing.

According to the third aspect of the invention, the operation is the same as that of the second aspect of the invention, except that the autofocus is performed between the photometry by the first photometry means and the photometry by the second photometry means. Controlled to do so. In this case, the exposure associated with the autofocus operation is performed based on the photometric value selected by the selection unit, so that the accuracy of the autofocus can be improved. Since the main exposure is performed at the same flicker timing as that at the time of photometry, a correct exposure amount can be obtained without being affected by flicker.

According to a fourth aspect of the present invention, there is provided an electronic imaging apparatus according to the second aspect, further comprising a step of performing a step between the photometry by the second photometry unit and the exposure by the exposure amount control unit. The aperture is driven based on the aperture metering.

According to the fourth aspect of the present invention, there is provided the second aspect.
Operates in the same manner as the invention, but between the photometry by the second photometry unit and the exposure by the exposure amount control unit,
The aperture is controlled to be driven based on the aperture metering. By driving the aperture to, for example, the open state during the main exposure, more reliable auto exposure control can be performed, and the main exposure can be performed at the same flicker timing as in the photometry regardless of the auto focus operation period. Is performed, so that flicker is not affected.

[0024]

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

(First Embodiment) FIGS. 1 and 2 relate to a first embodiment of an electronic imaging apparatus according to the present invention, and FIG. 1 shows an electronic imaging apparatus used in each embodiment of the present invention. FIG. 2 is a block diagram showing a specific configuration example of the apparatus, and FIG. 2 is a timing chart for explaining a control operation of an AE scan method employed in the apparatus of the first embodiment.

The electronic image pickup apparatus 1 shown in FIG. 1 has a zoom lens 2 and a focus lens 3 as an image pickup optical system, and a light beam passing through these lenses passes through a stop 4 to a CCD 5 as a solid-state image pickup device. Tie the statue.

The signal photoelectrically converted by the CCD 5 is input to an imaging circuit 6, which generates a video signal. The video signal is converted into a digital video signal (image data) by an A / D converter 7. And temporarily stored in the memory 8.

The image data stored in the memory 8 is read out at a predetermined screen rate (for example, 1/30 sec.),
After being converted into an analog video signal by the converter 9, a subject image is displayed on a liquid crystal display element (abbreviated as LCD) 10.

When a recording operation is performed by operating the release switch of the operation switch 24, the image data in the memory 8 is compressed by the compression circuit of the compression / expansion circuit 11 and then stored in the recording memory 12. Is done.

When a reproducing operation is performed, the data compressed and stored in the recording memory 12 is expanded by the expansion circuit of the compression / expansion circuit 11 and temporarily stored in the memory 8, and the image data is stored. Is converted into an analog video signal by a D / A converter 9 and then a reproduced image is displayed on a liquid crystal display (LCD) 10.

The image data A / D converted by the A / D converter 7 is input to an auto exposure processing circuit (abbreviated as AE processing circuit) 13 and an auto focus processing circuit (abbreviated as AF processing circuit) 14. The AE processing circuit 13 calculates an AE evaluation value corresponding to the brightness of the subject by, for example, calculating a luminance value of image data for one frame (one screen).
Output to PU15.

The AF processing circuit 14 extracts a high-frequency component of the luminance component of the image data for one frame (one screen) using a high-pass filter or the like, and calculates a cumulative addition value to thereby obtain a contour on the high frequency side. An AF evaluation value corresponding to the component amount or the like is calculated and output to the CPU 15.

A predetermined timing signal synchronized with the screen rate is input from a timing generator (abbreviated as a TG circuit) 16 to the CPU 15, and the CPU 15 performs various control operations in synchronization with the timing signal.

The timing signal of the TG circuit 16 is also input to the imaging circuit 6, and performs processing such as separation of color signals in synchronization with the signal.

The TG circuit 16 controls the CCD driver 17 to drive the CCD 5 at a predetermined timing.

The CPU 15 controls the first, second and third motor drive circuits 18, 19 and 20, respectively, to control the apertures 4 and 4 via the first, second and third motors 21, 22 and 23. The drive of the focus lens 3 and the zoom lens 2 is controlled.

That is, the CPU 15 uses the AE evaluation value
The first motor drive circuit 18 is controlled to rotate the first motor 21 to adjust the aperture amount of the aperture 4 to an appropriate value, that is, to perform automatic exposure control.

The CPU 15 controls the second motor drive circuit 19 based on the AF evaluation value to control the second motor 2
2 is rotationally driven to obtain an AF evaluation value from the AF processing circuit 14. Based on the obtained AF evaluation value, the CPU 15 drives the focus lens 3 to the lens position where the value becomes the maximum, and sets the focus state, that is, performs autofocus.

In the present embodiment, when the AF evaluation value is obtained and the focus position is set, the screen rate (for example, 1/30) when the CCD 5 captures one frame (one screen) of the subject.
Per second) and the focus lens 3
The focus lens 3 is moved by a predetermined feed amount within a movable range in the optical axis direction.

When the zoom UP switch of the operation switch 24 is operated, the operation signal is received and the CP is received.
U15 controls the third motor drive circuit 20 to rotate and drive the third motor 23 to drive the zoom lens 2 to the enlargement side.

The CPU 15 is connected to, for example, an electrically rewritable and non-volatile read-only memory (EEPROM) 25 as a memory.
The ROM 25 stores a program for performing various controls and the like via the CPU 15, data used for performing various operations, and the like, and is read out when the power of the imaging apparatus 1 is turned on. Used.

Note that the CPU 15 detects the voltage of the battery 26 and, when detecting that the voltage has dropped below a predetermined value, uses the LCD 10 to determine whether the battery 26 is low or to charge or replace the battery. Prompt display.

In this embodiment, as means for determining the brightness of a picked-up video signal, an aperture 4, an electronic element shutter (not shown) provided in the CCD 5, and an image pickup circuit 6
There are amplifiers (not shown) provided in the
It is controlled by the CPU 15.

For example, the diaphragm 5 may have a structure in which the opening and closing of the diaphragm can be driven so as to be freely adjustable. In this embodiment, a structure in which the diaphragm is driven in a two-stage system of opening and closing is used. The reason is that at the time of the first photometry performed in the photometry control described later, the aperture is opened to adjust the brightness so that AF can be performed as much as possible.
This is for improving the detection accuracy of F. In addition, by adopting a two-stage drive in which the aperture 5 is normally opened and the aperture is closed when necessary, there is an advantage that power consumption required for opening and closing can be reduced. It is.

The shutter speed of the electronic element shutter in the CCD 5 is controlled by the CCD driver 17 so as to adjust the accumulation time of the light of the object to be imaged and to adjust the brightness of the signal to be photoelectrically converted accordingly. I do. Further, an amplifier (not shown) in the imaging circuit 6 amplifies the luminance level of the generated video signal, and the gain is controlled by the gain control of the CPU 15 so that the gain of the video signal is varied. Make adjustments. Thereby, the brightness can be adjusted at the time of imaging.

In the present embodiment, in order to obtain an accurate exposure amount at the time of main exposure and to shorten the processing time involved in exposure control from the start of the release operation to the main exposure, C
The PU 15 performs AE in the first photometry performed first after the release operation among the two photometry performed before the main exposure.
Scan type photometry (hereinafter referred to as AE scan exposure)
Is performed, and an optimal exposure detection result is selected from a plurality of exposure detection values obtained by the AE scan exposure, and a second pre-photometry (also referred to as a pre-photometry exposure) is performed based on the selected exposure detection value. The main exposure is controlled based on the result of the exposure detection by the pre-metering.

For example, in the AE scan type photometry, the CPU 15 performs a release operation and then, with the aperture 5 open, for each timing signal (for example, a vertical synchronization signal VD) supplied from the TG circuit 16. By controlling the CCD driver 17, the exposure is performed by sequentially switching and setting the shutter speed from a high shutter speed within an entire shutter speed range of an electronic element shutter (not shown) in the CCD.

As a result, all brightnesses can be
A plurality of exposure detection results (exposure detection values) based on the exposure for each shutter speed can be obtained.

When the exposure based on a certain shutter speed is completed, the CPU 15 sets the AE based on the exposure detection value of the shutter speed in a period during which the next vertical synchronizing signal is supplied.
An AE process for obtaining an evaluation value is performed, and it is further determined whether or not the AE evaluation value is based on an optimal exposure value of a subject during a period in which a next vertical synchronization signal is supplied. As a result, a determination result corresponding to each shutter speed can be obtained. These judgment results are based on CP
It is temporarily stored in a memory (not shown) in U15.

When the exposure based on the last set shutter speed is completed, the CPU 15 determines the optimum exposure value for the subject from all the determination results including the AE evaluation value after the determination of the AE evaluation value at this time. A determination result closest to the obtained one is selected, and control is performed to perform an arithmetic process for correcting the exposure amount to an optimal amount based on the selected determination result. This makes it possible to obtain an optimal exposure value (AE evaluation value) for adjusting the brightness at least in a state in which AF is performed.

After that, when the AE scan exposure is completed, the CPU 15 sets the AE scan exposure based on the AE evaluation value selected as the optimum exposure detection result closest to the exposure amount of the subject from the plurality of exposure detection results obtained by the AE scan exposure. , So that pre-metering is performed.

In the pre-metering, the AE scan exposure obtains at least an optimum AE evaluation value for adjusting the brightness to a state in which AF is performed. Therefore, the AE processing is performed based on the selected AE evaluation value. By performing photometry again based on the AE evaluation value calculated by the circuit 13, an exposure value in a state as close as possible to the main exposure (imaging) is obtained. The main exposure is performed based on the exposure value obtained by the pre-photometry.
Based on the AE evaluation value calculated by the processing circuit 13, the final exposure, that is, the exposure at the time of imaging is determined by this exposure.

Therefore, according to the above configuration, of the two photometric operations performed before the main exposure, the AE scan exposure is performed as the photometric operation performed after the release operation, and the optimal exposure value is selected from a plurality of obtained exposure values. By controlling pre-metering based on the selected exposure value, it is possible to significantly reduce the processing time from the start of the release operation to the main exposure as compared with the conventional feedback control and other exposure control methods. Become.

Further, since the main exposure is controlled so as to be performed based on the exposure value based on the pre-metering, an image can be taken with a correct exposure amount.

Next, the characteristic operation of this embodiment will be described with reference to FIG.
This will be described in detail with reference to FIG.

2A is a vertical synchronizing signal, FIG. 2B is AE scan exposure performed at each shutter speed of an electronic element shutter, and FIG. 2C is image data from a CCD. Readout and AE processing, FIG.
The processing contents such as the determination processing with the target value by the PU and the calculation processing are shown.

Now, it is assumed that after the power of the electronic imaging apparatus 1 of FIG. 1 is turned on, the imaging mode of the AE scan exposure is set, and the imaging of the subject is performed. At this time, the user operates the operation switch.
Assuming that the release operation has been performed by the CPU 24, the CPU
15 controls the AE scan exposure with the aperture 5 open at time t1 when the first vertical synchronization signal VD is supplied as shown in FIG. Approximate exposure value for adjusting the brightness to the state in which is performed.

For example, the CPU 15 controls the CCD driver 17 at time t1 when the vertical synchronization signal VD is supplied as shown in the figure to control the shutter speed of an electronic element shutter (not shown) provided in the CCD. Is the earliest, 1 /
It is set to 12,000 s, and control is performed so that exposure 1 is performed.

Thereafter, the CPU 15 outputs the vertical synchronization signal VD
The shutter speed of the electronic element shutter is set to 1/6, 400s, 1/3, 200s, 1 /
3,200s, 1 / 1,600s, 1 / 800s, 1 /
400 s, 1/200 s, 1/100 s, and 1/50 s, which are sequentially switched and set. Exposure 2, Exposure 3, Exposure 4, Exposure 5, Exposure 6, Exposure 7, Exposure 7 and Exposure 8 corresponding to the respective shutter speeds. And exposure 9 are sequentially performed.

The above-mentioned shutter speed is not limited to this, but a plurality of shutter speeds or a shutter speed within a certain range is set to be limited, and the exposure is performed correspondingly. Is also good.

Therefore, as shown in the figure, exposure 1 is performed at time t1, exposure 2 at time t2, exposure 3 at time t3, exposure 4 at time t4, exposure 5 at time t5, and
Exposure 6 is performed at time t6, exposure 7 is performed at time t7, exposure 8 is performed at time t8, and exposure 8 is performed at time t9. In other words, in this case, scan exposure is performed so that nine exposures are performed. Become.

Further, the CPU 15 is different from the conventional one, when the exposures 1 to 9 are completed, at the time when the next vertical synchronizing signal VD is supplied, the photoelectric conversion is performed by the CCD 5 at the time of the exposure performed one frame before. After reading the converted signal and generating it as a video signal by the imaging circuit 6, the image data digitized by the A / D converter 7 is supplied to the AE processing circuit 13 to control the AE processing. The AE evaluation value obtained at this time is supplied to the CPU 15.

Therefore, as shown in FIG.
Then, the capture of the captured video signal at the time of the exposure 1 and the AE processing are performed.
At time t6, at 5:00, at time t7, at 6:00, at time t8, at 7:00, at time t9, at 8:00, and at time t10, the capture of the imaging signal and the AE process are performed sequentially. Will be.

When the AE process for each exposure is completed, the CPU 15 determines, at the time when the next vertical synchronizing signal VD is supplied, the AE evaluation value of the exposure performed one frame before and the optimum subject. Judgment with the AE evaluation value (target value) is performed, the judgment results are sequentially stored, and after the judgment based on the final exposure is performed, the judgment result (AE evaluation value) obtained by all the exposures is used. Selecting an AE evaluation value corresponding to the most optimal brightness, performing a calculation operation of a correction value required to obtain an optimal brightness of the subject based on the selected AE evaluation value, and calculating the AE evaluation value. Update as CP
It is temporarily stored in a memory or the like (not shown) in U15.

Therefore, by performing the AE scan exposure in this manner, a plurality of exposure values corresponding to all brightnesses can be obtained, and an exposure value having an optimum brightness is selected from the plurality of exposure values and calculated. By performing the processing, it is possible to obtain an AE evaluation value necessary for correcting the brightness to the optimal brightness.

Thereafter, the CPU 15 executes the AE scan exposure before performing the pre-photometric exposure.
Based on the evaluation value, the first motor drive circuit 18 is controlled to rotate the first motor 21 so that the aperture of the aperture 4 is opened, and at the same time, the electronic element shutter speed in the CCD 5 and the imaging circuit After adjusting and setting the amplification factor of the amplifier in 6, control is performed so as to perform pre-photometric exposure.

In the pre-photometric exposure, the exposure is performed based on the exposure detection result (AE evaluation value) selected from the plurality of exposure detection results by the AE scan exposure as described above.
As a result, an exposure value in a state as close as possible to the main exposure (at the time of imaging) is obtained.

Then, the CPU 15 performs final exposure based on the AE evaluation value calculated by the AE processing circuit 13 based on the exposure value obtained by the pre-photometry, that is, the final exposure, The exposure is determined.

The subsequent operation is the same as the recording sequence of a general electronic camera.
Is from time t7 when the next vertical synchronization signal VD is supplied.
After the photoelectrically converted signal is read by the CCD 5 and the image signal is generated into a video signal by the imaging circuit 6, the image data digitized by the A / D converter 7 is temporarily stored in the memory 8 and then stored in the memory 8. Image data
The image data is controlled to be displayed on the screen of the LCD 10 via the / A converter 9 and stored in the recording memory 12 via the compression / expansion circuit 11.

In this way, the control operation associated with the imaging is completed.
A standby state is entered in response to a release operation accompanying the next imaging.

Therefore, by employing the above-described AE scan exposure method, it takes a time corresponding to nine frames to obtain an exposure value corresponding to, for example, three shutter speeds. Then, by performing AE scan exposure as the first photometry performed after the release operation, only the time corresponding to six frames is required.

That is, in the case of obtaining exposure values corresponding to nine shutter speeds as in the present embodiment, 1
While the time corresponding to one frame is required, the conventional feedback method (see FIG. 6) requires time corresponding to 27 frames. As a result, the processing time from the start of the release to the actual exposure can be significantly reduced as compared with the related art.

Therefore, according to the present embodiment, AE
By performing the scan exposure, the processing time from the start of the release to the main exposure can be reduced. Further, since a more optimal exposure amount is selected by the AE scan exposure, a correct exposure amount can be obtained, and the accuracy of autofocus can be improved.
This makes it possible to form an electronic imaging device having excellent quick shooting performance. Particularly, in an electronic imaging device such as an electronic camera having a narrow dynamic range of a CCD, the effect is remarkable and effective.

Conventionally, under a light source such as a fluorescent lamp which generates flicker, the brightness of the light source is different between the pre-metering and the main exposure, and accurate exposure control cannot be performed. There is. In particular, in the case where photometry is repeatedly performed as in the above embodiment, it becomes difficult to control the timing of photometry of each photometric value.

However, according to the present invention, accurate exposure control can be performed even under a light source such as a fluorescent lamp where flicker occurs. Such an embodiment will be described below.

(Second Embodiment) A second embodiment of the present invention will be described in detail with reference to FIG.

FIG. 3 shows a second embodiment of the electronic imaging apparatus according to the present invention.
FIG. 3A is a timing chart for explaining a control operation of the apparatus, wherein FIG. 3A shows an operation state of a release, FIG.
3C shows a vertical synchronization signal, FIG. 3D shows exposure by photometry including AE scan exposure, FIG. 3E shows reading of image data from a CCD and AE processing, and FIG. 3F shows exposure calculation by a CPU. FIG. 3 (g) shows the electronic element shutter speed setting, and FIG. 3 (h) shows the gain adjustment by the amplifier of the imaging circuit 6.

Normally, in an electronic imaging apparatus such as an electronic camera, a correct exposure cannot be obtained unless the exposure during pre-metering and the exposure during main exposure match.

For example, the light source is a fluorescent lamp and the power frequency is 50H
When imaging in the eastern region of z, flicker occurs due to the difference between the fluorescent lamp that blinks every 1/50 second and the shutter speed of the electronic imaging device, and the influence of the flicker causes pre-photometry and main exposure. Timing is shifted. That is, since the brightness at the time of the pre-metering and the brightness at the time of the main exposure are different, a correct exposure cannot be obtained. In particular, this is an important problem in an electronic image pickup apparatus having an image pickup element whose dynamic range is narrower than that of a silver halide film or the like.

Therefore, in the present embodiment, the exposure control method including the AE scan exposure in the first embodiment is performed, and a time interval between the timing of the AE scan exposure and the timing of the pre-photometric exposure is performed. The second embodiment is different from the first embodiment in that the time interval between the pre-photometry timing and the main exposure timing is controlled to be an integral multiple of 3 of the screen rate. .

The configuration of the present embodiment is the same as the circuit configuration of the first embodiment (see FIG. 1).
The control content of the PU 15 is different.

Specifically, in order to enable accurate control of the exposure amount without being affected by flicker such as a fluorescent lamp, the CPU 15 determines the start timing of the scan exposure performed first after the release operation, The respective time intervals between the start timing of the pre-photometric exposure performed at the second time and the start timing of the main exposure are controlled so as to be an integral multiple of 3 of the screen period not affected by the flicker period.

In this case, in the AE scan exposure, the exposure detection result based on the frame corresponding to the optimum brightness is selected from the plurality of exposure detection results obtained as described in the first embodiment. Exposure is performed based on the selected exposure detection result (AE evaluation value). As a result, an optimal exposure value for adjusting the brightness to at least the state in which AF is performed is obtained.

In the pre-photometric exposure, photometry is performed again on the basis of the AE evaluation value calculated by the AE processing circuit 13 based on the exposure value obtained by the scan exposure, so that the main exposure (at the time of imaging) is performed. Obtain an exposure value that is as close as possible. The final exposure is based on the AE evaluation value calculated by the AE processing circuit 13 based on the exposure value obtained by the pre-photometry, and the final exposure, that is, the exposure at the time of imaging is determined by this exposure. In this case, the timing at the time of photometry is TG
By using the vertical synchronizing signal VD supplied from the CPU 16, the CPU 15 controls the screen cycle (screen rate) to be an integral multiple of 3 as described above.

Therefore, according to the above configuration, AE scan exposure is performed, and the timing interval at the time of photometry is controlled by the CPU 15 so as to be an integral multiple of 3 of the screen period (screen rate). It is possible to match the state of the light source at the time of photometry, that is, the brightness, so that it is possible to obtain an accurate exposure amount without being affected by a flicker cycle due to a fluorescent lamp or the like.

Next, the characteristic operation of the second embodiment of the present invention will be described in detail with reference to FIG.

Now, it is assumed that, after turning on the power of the electronic imaging apparatus 1 of FIG. 1, this imaging mode is set, and an image of a subject is taken under a light source such as a fluorescent lamp. At this time, assuming that the user has performed a release operation by the operation SW 24 at time t0, the CPU 15 sets the aperture 5 to the open state at time t1 when the first vertical synchronization signal VD is supplied as shown in the figure. Control is performed to perform AE scan exposure, and an approximate exposure value for adjusting brightness at least to a state in which AF is performed is obtained.

In this case, in the AE scan exposure, the exposure detection result (exposure value based on the selected frame) selected from the plurality of exposure detection results obtained as described with reference to FIG. Exposure is performed based on

After that, at time t2 when the next vertical synchronizing signal VD is supplied, the signal photoelectrically converted by the CCD 5 at the time of this AE scan exposure is read, and after the image signal is generated by the imaging circuit 6, the A / The image data digitized by the D converter 7 is supplied to an AE processing circuit
The AE evaluation value obtained at this time is
Supplied to

Then, at time t3 when the next vertical synchronizing signal VD is supplied, the CPU 15 calculates and calculates a correction value necessary to obtain the optimum brightness of the subject based on the supplied AE evaluation value. And update this as the AE evaluation value.
It is temporarily stored in a memory (not shown) in the PU 15.

Next, the CPU 15 outputs the next vertical synchronizing signal V
At time t4 when D is supplied, pre-photometric exposure is performed.
Immediately before performing the pre-photometric exposure, the first motor drive circuit 18 is controlled to rotate and drive the first motor 21 based on the AE evaluation value obtained and held by the AE scan exposure. After the aperture of the aperture 4 is opened, and at the same time the shutter speed of the electronic element in the CCD 5 and the amplification factor of the amplifier in the imaging circuit 6 are adjusted and set, control is performed so as to perform pre-photometric exposure. An exposure value in a state as close as possible at the time of main exposure (at the time of imaging) is obtained. in this case,
The start timing at the time of pre-metering is controlled to be an integer multiple of 3 of the screen rate from the start timing at the time of the AE scan exposure.

Thereafter, at time t5 when the next vertical synchronizing signal VD is supplied, the signal photoelectrically converted by the CCD 5 at the time of this pre-photometric exposure is read, and after being generated into a video signal by the image pickup circuit 6, A The image data digitized by the / D converter 7 is supplied to the AE processing circuit 13 to perform AE processing, and the AE evaluation value obtained at this time is supplied to the CPU 15.

Then, similarly to the AE scan exposure, the CPU 15 sets the time t at which the next vertical synchronizing signal VD is supplied.
At 6, the CPU performs a calculation operation for calculating a correction value necessary to obtain the optimum brightness of the subject based on the AE evaluation value supplied again, updates the correction value as an AE evaluation value, and stores a memory (not shown) in the CPU 15 or the like. Temporarily. That is, the AE evaluation value obtained by the pre-photometric exposure is at a level close to the AE evaluation value at the time of the main exposure (at the time of imaging).

Thereafter, under the control of the CPU 15,
The main exposure is performed at time t7 when the next vertical synchronizing signal VD is supplied. In this case, the start timing of the main exposure is three times the screen rate from the start timing of the pre-photometric exposure. It is controlled to be an integral multiple.

Further, immediately before performing the main exposure, the CPU 15 determines whether or not the aperture of the aperture 4 is in the open state based on the AE evaluation value obtained and held by the pre-exposure metering exposure. After adjusting and setting the element shutter speed and the amplification factor of the amplifier in the imaging circuit 6, control is performed so that main exposure is performed.

In the main exposure, the final exposure is performed based on the AE evaluation value obtained by the pre-photometric exposure as described above, and a signal photoelectrically converted by the CCD 5 at the time of the main exposure is read, and image pickup is performed. After being generated into a video signal by the circuit 6, the image data digitized by the A / D converter 7 is supplied to an AE processing circuit 13 to perform AE processing.
The AE evaluation value obtained at this time is supplied to the CPU 15,
At the same time, the CPU 15 performs a calculation operation for calculating a correction value necessary to obtain the optimal brightness of the subject based on the AE evaluation value, and performs an auto AE process using the correction value as a final AE evaluation value.

The subsequent operation is the same as the recording sequence of a general electronic camera.
Is from time t7 when the next vertical synchronization signal VD is supplied.
After the photoelectrically converted signal is read by the CCD 5 and the image signal is generated into a video signal by the imaging circuit 6, the image data digitized by the A / D converter 7 is temporarily stored in the memory 8 and then stored in the memory 8. Image data
The image data is controlled to be displayed on the screen of the LCD 10 via the / A converter 9 and stored in the recording memory 12 via the compression / expansion circuit 11.

In the above embodiment, the auto focus (AF process) is appropriately performed during a predetermined period after the AE scan exposure.

In this way, the control operation associated with the imaging is completed.
A standby state is entered in response to a release operation accompanying the next imaging.

Therefore, according to the present embodiment, the processing time from the release operation to the main exposure can be reduced by performing the AE scan exposure in the same manner as in the first embodiment. , The time interval between the timing of the AE scan exposure and the timing of the pre-photometric exposure and the time interval between the timing of the pre-photometric exposure and the timing of the main exposure are set to an integral multiple of 3 of the screen rate. By controlling, even when imaging is performed under a light source such as a fluorescent lamp, the main exposure is performed at the same flicker cycle timing as in photometry, so that a correct exposure amount can be obtained without being affected by flicker.

As a result, it is possible to realize an electronic image pickup apparatus which has an accurate exposure amount even under a light source in which flicker occurs and is excellent in quick shooting performance. Further, an additional circuit such as a flicker detection unit, which is conventionally required, is not required, thereby preventing an increase in circuit scale and contributing to cost reduction.

(Third Embodiment) Next, a third embodiment of the present invention will be described in detail with reference to FIG.

FIG. 4 is a timing chart for explaining a control operation of the electronic image pickup apparatus according to a third embodiment of the present invention, and FIG. FIG. 4B shows the open / closed state of the aperture 5, FIG.
4C shows a vertical synchronizing signal, FIG. 4D shows exposure by photometry including AE scan exposure, FIG. 4E shows reading of image data from a CCD and AE processing, and FIG. 4F shows exposure calculation processing by a CPU. 4 (g) shows the electronic element shutter speed setting, and FIG. 4 (h) shows the gain adjustment by the amplifier of the imaging circuit 6.

In this embodiment, the operation is almost the same as the control operation in the second embodiment.
The timing at the time of the AE scan exposure and the timing at the time of the pre-photometric exposure are controlled so as to be an integral multiple of 3 of the screen rate, and the auto-focus is performed during the period between the AE scan exposure and the pre-photometric exposure. What is different from the second embodiment is that it is performed.

The configuration of the present embodiment is the same as the circuit configuration of the first embodiment (see FIG. 1).
The control content of the PU 15 is different. FIG. 4 shows an example of the control operation content of the present embodiment.

In the present embodiment, in order to start imaging in this mode, the user operates the operation switch at time t0.
Assuming that the release operation has been performed by the CPU 24, the CPU
Reference numeral 15 denotes control such that AE scan exposure is performed with the aperture 5 open at time t1 when the first vertical synchronization signal VD is supplied, as in the second embodiment, and at least AF is performed. An approximate exposure value for adjusting the brightness to the state is obtained.

In this case, in the AE scan exposure, an exposure detection result (an exposure based on a selected frame) is selected from the plurality of exposure detection results obtained in the same manner as in the second embodiment so as to obtain optimum brightness. Value).

Thereafter, at time t2 when the next vertical synchronizing signal VD is supplied, the signal photoelectrically converted by the CCD 5 at the time of the AE scan exposure is read, and the signal is generated by the image pickup circuit 6 into a video signal. The image data digitized by the D converter 7 is supplied to an AE processing circuit
The AE evaluation value obtained at this time is
Supplied to

Then, at time t3 when the next vertical synchronizing signal VD is supplied, the CPU 15 calculates and calculates a correction value necessary for obtaining the optimum brightness of the subject based on the supplied AE evaluation value. And update this as the AE evaluation value.
It is temporarily stored in a memory (not shown) in the PU 15.

Next, the CPU 15 sets the next vertical synchronizing signal V
At time t4 when D is supplied, control is performed so that autofocusing is performed, and exposure associated with the execution of autofocusing, that is, AF exposure is performed. In this case, the A
Immediately before performing the exposure for F, the CPU 15 determines the shutter speed of the electronic element in the CCD 5 and the imaging based on the AE evaluation value obtained and held by the AE scan exposure while the aperture amount of the aperture 4 is kept open. After adjusting and setting the amplification factor of the amplifier in the circuit 6, control is performed so that exposure for AF is performed, and an exposure value at the time of executing autofocus is obtained.

Actually, the exposure for AF is performed according to the execution period of the auto focus, and it is not known how long it takes. Therefore, the CPU 15
When the end of the exposure for F is confirmed, the first motor drive circuit 18 is controlled to rotate and drive the first motor 21 based on the AE evaluation value obtained by the exposure for AF,
The aperture of the aperture 4 is closed, and at the same time, the CCD 5
After adjusting and setting the electronic element shutter speed and the amplification factor of the amplifier in the imaging circuit 6, the exposure value in a state as close as possible to the main exposure (imaging) is controlled by performing pre-photometric exposure. Get.

At this time, the timing of the pre-photometric exposure is controlled so as to be an integral multiple of 3 of the screen rate from the timing of the AE scan exposure so as not to be affected by the flicker cycle.

For example, assuming that the exposure for AF ends at time 7, the exposure for pre-metering is controlled so as to be completed from time t2 at which the AE scan exposure ends to time t8 which is twice the screen rate of three. . The pre-metering exposure is performed based on the exposure value obtained by the AF exposure.

Then, at time t8, the CPU 15 reads the signal photoelectrically converted by the CCD 5 at the time of the pre-photometric exposure, generates the image signal by the image pickup circuit 6, and then converts the signal into a digital signal by the A / D converter 7. The converted image data is supplied to the AE processing circuit 13 to perform AE processing, and the AE evaluation value obtained at this time is supplied to the CPU 15.

Then, the CPU 15 obtains the optimal brightness of the subject based on the supplied AE evaluation value at time t9 when the next vertical synchronizing signal VD is supplied, as in the case of the photometric exposure. A necessary correction value is calculated and calculated, updated as an AE evaluation value, and temporarily stored in a memory (not shown) in the CPU 15. That is, the AE evaluation value obtained by the pre-photometric exposure is at a level close to the AE evaluation value at the time of the main exposure (at the time of imaging).

Thereafter, under the control of the CPU 15,
The main exposure is performed at time t10 when the next vertical synchronizing signal VD is supplied. In this case, the start timing of the main exposure is three times the screen rate from the start timing of the pre-photometric exposure. It is controlled to be an integral multiple.

Further, immediately before performing the main exposure, the CPU 15 determines whether or not the aperture of the aperture 4 is in the open state based on the AE evaluation value obtained and held by the pre-photometric exposure while the electronic After adjusting and setting the element shutter speed and the amplification factor of the amplifier in the imaging circuit 6, control is performed so that main exposure is performed.

The subsequent operation is the same as in the above-described second embodiment.

Therefore, according to the present embodiment, AE
In the period between the scan exposure and the pre-photometric exposure,
By performing the autofocus and performing control to perform the AF exposure accompanying the execution of the autofocus, the accuracy of the autofocus can be further improved.

The time interval between the timing of the AE scan exposure and the timing of the pre-photometric exposure, and the time between the timing of the pre-photometric exposure and the timing of the main exposure irrespective of the autofocus execution period. By controlling the interval so as to be an integral multiple of 3 of the screen rate, even when imaging is performed under a light source such as a fluorescent lamp, the main exposure is performed at the same flicker cycle timing as that during photometry. A correct exposure can be obtained without being affected by the above.

The other effects are the same as those of the first and second embodiments.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described in detail with reference to FIG.

FIG. 5 shows a fourth embodiment of the electronic imaging apparatus according to the present invention, and is a timing chart for explaining the control operation of the electronic imaging apparatus. FIG. FIG. 5 (b) is the open / closed state of the aperture 5, FIG.
5C shows a vertical synchronization signal, FIG. 5D shows exposure by photometry including AE scan exposure, FIG. 5E shows reading of image data from a CCD and AE processing, and FIG. 5F shows exposure calculation by a CPU. FIG. 5 (g) shows the electronic element shutter speed setting, and FIG. 5 (h) shows the gain adjustment by the amplifier of the image pickup circuit 6, respectively.

In the present embodiment, the operation is almost the same as the control operation in the third embodiment.
The timing of the AE scan exposure and the timing of the pre-photometric exposure, and the timing of the pre-photometric exposure and the main exposure are controlled so as to be an integral multiple of 3 of the screen rate. The difference from the third embodiment is that the aperture drive control is performed on the basis of the exposure amount obtained by the pre-photometric exposure during the period between the exposure.

The configuration of the present embodiment is the same as the circuit configuration of the first embodiment (see FIG. 1).
The control content of the PU 15 is different. FIG. 4 shows an example of the control operation content of the present embodiment.

In this embodiment, in order to start imaging in this mode, the user operates the operation switch at time t0.
Assuming that the release operation has been performed by the CPU 24, the CPU
Reference numeral 15 denotes control such that AE scan exposure is performed with the aperture 5 open at time t1 when the first vertical synchronization signal VD is supplied, as in the third embodiment, and at least AF is performed. An approximate exposure value for adjusting the brightness to the state is obtained.

In this case, also at the time of AE scan exposure, similarly to the third embodiment, an exposure detection result selected from the plurality of exposure detection results obtained so as to obtain the optimum brightness (for the selected frame). Exposure is performed on the basis of an exposure value based on the above.

Thereafter, at time t2 when the next vertical synchronizing signal VD is supplied, the signal photoelectrically converted by the CCD 5 at the time of this AE scan exposure is read, and after being generated as a video signal by the imaging circuit 6, The image data digitized by the D converter 7 is supplied to an AE processing circuit
The AE evaluation value obtained at this time is
Supplied to

Then, at time t3 when the next vertical synchronizing signal VD is supplied, the CPU 15 calculates and calculates a correction value necessary for obtaining the optimum brightness of the subject based on the supplied AE evaluation value. And update this as the AE evaluation value.
It is temporarily stored in a memory (not shown) in the PU 15.

Next, the CPU 15 outputs the next vertical synchronizing signal V
At time t4 when D is supplied, control is performed so that autofocusing is performed, and exposure associated with the execution of autofocusing, that is, AF exposure is performed. In this case, the A
Immediately before performing the exposure for F, the CPU 15 determines the shutter speed of the electronic element in the CCD 5 and the imaging based on the AE evaluation value obtained and held by the AE scan exposure while the aperture amount of the aperture 4 is kept open. After adjusting and setting the amplification factor of the amplifier in the circuit 6, control is performed so that exposure for AF is performed, and an exposure value at the time of executing autofocus is obtained.

When the CPU 15 confirms that the exposure for AF has been completed, the CPU 15 controls the first motor drive circuit 18 based on the AE evaluation value obtained by the exposure for AF to control the first motor drive circuit 18.
The motor 21 is rotated to bring the aperture of the aperture 4 into a closed state, and at the same time, the shutter speed of the electronic element in the CCD 5 and the amplification factor of the amplifier in the imaging circuit 6 are adjusted and set. Exposure is controlled to obtain an exposure value in a state as close as possible to the time of main exposure (at the time of imaging). At this time, the timing of the pre-photometric exposure is controlled so as to be an integral multiple of 3 of the screen rate from the timing of the photometric exposure so as not to be affected by the flicker cycle.

For example, assuming that the exposure for AF is completed at time 7, the exposure for pre-photometry is controlled so as to be completed from time t2 at which the AE scan exposure is completed to time t8 which is twice the screen rate of three. . The pre-metering exposure is performed based on the exposure value obtained by the AF exposure.

Then, the CPU 15 reads the signal photoelectrically converted by the CCD 5 at the time of the pre-photometric exposure at the time t8, generates the image signal by the image pickup circuit 6, and then converts the signal into a digital signal by the A / D converter 7. The converted image data is supplied to the AE processing circuit 13 to perform AE processing, and the AE evaluation value obtained at this time is supplied to the CPU 15.

Then, as in the case of the AE scan exposure, the CPU 15 sets the time t at which the next vertical synchronizing signal VD is supplied.
At 9, a calculation operation for calculating a correction value necessary to obtain the optimal brightness of the subject is performed based on the supplied AE evaluation value, and the calculated correction value is updated as an AE evaluation value and stored in a memory (not shown) in the CPU 15. Hold temporarily.

Thereafter, under the control of the CPU 15,
The main exposure is performed. In this case, the start timing at the time of the main exposure is controlled so as to be an integral multiple of 3 of the screen rate from the start timing at the time of the pre-photometric exposure.

Further, immediately before performing the main exposure, the CPU 15 executes the first motor drive circuit 1 based on the AE evaluation value obtained and held by the pre-photometric exposure.
8, the first motor 21 is driven to rotate, and the aperture of the diaphragm 4 is opened again. With the aperture of the aperture 4 kept open, the shutter speed of the electronic element in the CCD 5 and the imaging circuit 6 After the gain of the amplifier is adjusted and set, control is performed so as to perform the main exposure.

The subsequent operation is the same as in the above-described second embodiment.

Therefore, according to the present embodiment, during the period between the pre-photometric exposure and the main exposure, the aperture 4 is driven to open based on the AE evaluation value obtained by the pre-photometric exposure. By performing the control, the exposure amount can be detected more reliably, and therefore, the accuracy of the automatic exposure control can be further improved.

The time interval between the timing of the AE scan exposure and the timing of the pre-photometric exposure, and the time between the timing of the pre-photometric exposure and the timing of the main exposure, regardless of the execution period of the autofocus. By controlling the interval so as to be an integral multiple of 3 of the screen rate, even when imaging is performed under a light source such as a fluorescent lamp, the main exposure is performed at the same flicker cycle timing as that during photometry. A correct exposure amount can be obtained without being affected by the above, and the same effect as in the third embodiment can be obtained.

The other effects are the same as those of the first and second embodiments.

In the first to fourth embodiments according to the present invention, the description has been given of the use of the diaphragm having a structure driven in a two-stage system of opening and closing. However, the present invention is not limited to this. A structure in which the opening and closing of the aperture are driven so as to be freely adjustable may be used.

In the first to fourth embodiments, a description has been given of the case where a single-stage switch is used as the release switch of the operation SW. However, a two-stage release switch may be used. good. In this case, the first
In the first release operation of turning on the release switch of A, the exposure is performed through exposure such as AE scan exposure and pre-photometric exposure.
The settings for E and AF are made, and the second release operation in which the second release switch is turned ON allows the main exposure, that is,
The configuration is such that actual shooting is performed. Also, the timing of each exposure at this time is similarly controlled to be an integral multiple of 3 of the screen rate, so that the influence of flicker can be prevented.

In the first to fourth embodiments, when the optimum exposure amount cannot be obtained by one AE scan exposure, control may be performed so that AE exposure is performed continuously. In this case, the time interval from the timing of the subsequent pre-photometric exposure is also controlled to be an integral multiple of 3 of the screen rate. As a result, it is possible to prevent the influence of flicker, to obtain a more accurate exposure amount, and to realize an electronic imaging apparatus with excellent quick shooting performance.

It should be noted that embodiments and the like constituted by partially combining the above-described embodiments and the like also belong to the present invention.

[0145]

As described above, according to the present invention, A
By performing the E-scan exposure, an accurate exposure amount can be obtained, and the processing time from the release operation to the main exposure can be shortened. In particular, it is effective for an electronic image pickup apparatus having a CCD with a narrow dynamic range.

Further, by performing the photometry twice, that is, the AE scan exposure and the pre-photometry exposure before the main exposure, a more accurate exposure amount can be obtained, and the accuracy of the autofocus can be improved.

Further, since the main exposure can be controlled so as to be performed at the same flicker cycle timing as that at the time of photometry, an additional circuit for detecting flicker can be added even under a light source such as a fluorescent lamp where flicker occurs. Thus, it is possible to obtain a correct exposure amount without being affected by flicker. As a result, it is possible to realize an electronic image pickup apparatus which has an accurate exposure amount even under a light source in which flicker occurs and which is excellent in quick shooting performance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an electronic imaging device according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining a control operation according to the first embodiment.

FIG. 3 is a timing chart for explaining a control operation according to a second embodiment.

FIG. 4 is a timing chart for explaining a control operation according to a third embodiment.

FIG. 5 is a timing chart for explaining a control operation according to a fourth embodiment.

FIG. 6 is a timing chart for explaining a conventional foot-back exposure control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electronic imaging device, 2 ... Zoom lens, 3 ... Focus lens, 4 ... Aperture, 5 ... CCD, 6 ... Imaging circuit, 7 ... A / D converter, 8 ... Memory, 9 ... D / A converter, 10 LCD, 11 compression / expansion circuit, 12 recording memory, 13 AE processing circuit, 14 AF processing circuit, 15 CPU, 16 TG circuit, 17 CCD driver, 18-20 motor drive circuit , 21-23 ... motor, 24 ... operation switch, 25 ... EEPROM, 26 ... battery.

Claims (4)

[Claims] An image pickup device that photoelectrically converts a subject image formed by an image pickup lens to generate a video signal, and responds to a shutter release signal while changing an exposure value for each screen with an aperture open. First photometric means for performing photometry to obtain a plurality of photometric values; selecting means for selecting an optimal photometric value from the plurality of photometric values measured by the first photometric means; and selecting by the selecting means Second light metering means for performing narrowed-down metering based on the obtained light metering value; and exposure amount controller for controlling the amount of exposure of the image sensor based on the light metering value measured by the second light metering means. An electronic imaging device, comprising: 2. An imaging device for photoelectrically converting a subject image formed by an imaging lens to generate a video signal, and for reading a video signal from the imaging device at a screen period of 1/60 seconds or 1/30 seconds. Video signal reading means; first photometry means for performing photometry while changing the exposure value for each screen with the aperture open in response to a shutter release signal to obtain a plurality of photometry values; Selecting means for selecting an optimum photometric value from the plurality of photometric values measured by the photometric means, a second photometric means for narrowing down the photometric value based on the photometric value selected by the selecting means, the second Exposure amount control means for controlling the exposure amount of the image sensor based on the photometric value measured by the photometric means, and the timing at which the photometric value selected by the selecting means is obtained and the aperture metering Time interval with timing,
And the time interval between the timing of the aperture metering and the timing of exposure by the exposure amount control means is set to 3
An electronic imaging apparatus, comprising: control means for setting an integral multiple of. 3. The electronic imaging apparatus according to claim 2, wherein autofocus is performed between photometry by the first photometry unit and photometry by the second photometry unit. 4. An electronic imaging apparatus according to claim 2, wherein an aperture is driven based on the aperture stop metering between the light metering by the second light metering unit and the exposure by the exposure amount controller. apparatus.