JP2765642B2 - Exposure control device for video camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control device for a video camera, and more particularly to an exposure control device for a video camera that automatically controls exposure according to the brightness of a subject.

[0002]

2. Description of the Related Art A conventional exposure control device for a video camera includes:
Exposure control is automatically performed so that an image with constant brightness can be obtained regardless of the brightness of the subject. That is, the iris opening is adjusted according to the brightness of the subject,
The amount of light incident on the image sensor via the iris is set to a standard set value, and the signal level of the electric signal converted by the image sensor is set to the standard set value.
The gain of the C amplifier is adjusted. Note that the exposure control here means control of the amount of light incident on the image sensor, gain control after conversion into an electric signal, and the like.

Further, as a recent video camera exposure control device, when the average luminance value at the center of the screen is higher than the average luminance value at the peripheral portion, a photometric value for exposure control is calculated by a center-weighted photometric method. When it is determined that an abnormal light is present at the center of the screen, a method has been proposed in which the photometric value for exposure control is corrected so that the peripheral portion is not too dark (Japanese Patent Application No. Hei 1-203580). Specification).

Further, a luminance signal of the subject image is input to a divided photometric circuit via a high luminance clip circuit, and the state of a photographic scene is determined based on each photometric information from the divided photometric circuit. If the scene is a backlight scene, an exposure control device for a video camera has been proposed in which the clip level in the high-brightness clipping circuit is lowered to reduce the influence of backlight when calculating a photometric value (Japanese Patent Laid-Open No. Hei 2-268080). No.).

[0005]

However, according to the exposure control of this type of conventional video camera exposure control apparatus, even if the subject is very bright or very dark, the brightness of a preset standard setting value is set. It will be taken with.
Therefore, there is a problem that the brightness of the photographed subject is considerably different from that of the subject actually seen by the naked eye, and becomes rather unnatural.

The exposure control apparatus for a video camera disclosed in Japanese Patent Application Laid-Open No. Hei 1-203580 only supports the center-weighted metering system, and only supports the case where the center is bright, and the case where the center is extremely dark. Is not taken into account. In addition, since two types of exposures are switched between a case where there is abnormal light and a case where there is no abnormal light, the exposure changes abruptly at the time of switching, resulting in an unnatural image.

On the other hand, in the exposure control apparatus for a video camera disclosed in Japanese Patent Application Laid-Open No. 2-268080, since a clipped luminance signal is used, the luminance comparison cannot be performed normally, and the abnormal light is erroneously determined. There is a possibility that. In order to avoid this, in addition to the clipped luminance signal, it is necessary to simultaneously measure a non-clipped luminance signal, which increases the circuit scale.

The present invention has been made in view of the above circumstances, and it is possible to shoot a bright subject relatively brightly and a dark subject relatively dark, and to capture an image closer to the sensation seen by human eyes. An object of the present invention is to provide an exposure control device for a video camera. Another object of the present invention is to reduce the spot light correction amount for extremely bright extraordinary light to prevent the surroundings from becoming too dark, and to perform excessive backlight correction when an extremely dark subject is photographed. An object of the present invention is to provide an exposure control device for a video camera that can prevent the surroundings from becoming too bright.

[0009]

In order to achieve the above object, the present invention provides at least one of an incident light amount from a photographic lens via an iris to an image sensor and a signal level of an electric signal converted by the image sensor. In a video camera exposure control device that controls one of them to be a standard setting value, a detecting means for detecting the brightness of the subject, and the brightness is increased when the brightness of the subject detected by the detecting means is higher than normal. And a correcting unit that corrects the standard setting value in a shooting direction and corrects the standard setting value in a shooting direction in a case where the brightness of the subject is darker than usual. still,
The correction means may correct the standard setting value only in a direction in which the image is taken brightly or in a direction in which the image is taken dark.

A correction means for obtaining an exposure correction amount based on a luminance signal indicating a subject image and correcting the standard setting value according to the exposure correction amount; a detection means for detecting brightness of the subject; An exposure correction amount limiter that reduces the spotlight correction amount in the exposure correction amount when the brightness of the subject detected by the detection unit increases, and reduces the backlight correction amount in the exposure correction amount when the brightness of the subject decreases. Means. Note that the exposure correction amount limiting means may be configured to reduce the correction amount only when the brightness of the subject increases or decreases.

[0011]

According to the present invention, the standard value of the exposure control is corrected in accordance with the brightness of the subject. That is, when the brightness of the subject is brighter than usual, the standard setting value is corrected in the direction of shooting brighter, and when the brightness of the subject is darker than normal, the standard setting value is corrected in the direction of shooting darker. As a result, a bright subject can be photographed relatively bright, and a dark subject can be photographed relatively dark, and photographing that is closer to the human eyes can be performed.

According to another aspect of the present invention, an exposure correction amount is obtained based on a luminance signal indicating a subject image, and a standard set value is corrected in accordance with the exposure correction amount. When the luminance distribution is in a backlight or spotlight illumination state, exposure correction is performed so that the center of the screen is appropriate. The upper limit of the exposure correction amount is limited in accordance with the brightness of the subject. For extremely bright extraordinary light, the correction amount is reduced to prevent the surroundings from becoming too dark. When the image is photographed, the surroundings are prevented from being too bright due to excessive backlight correction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an exposure control apparatus for a video camera according to the present invention will be described below in detail with reference to the accompanying drawings. [First Embodiment] FIG. 1 is a block diagram of a video camera including a first embodiment of an exposure control device for a video camera according to the present invention, and shows an example of application to a video movie camera having an average photometry type exposure control device. Is shown.

Referring to FIG.
Then, an image is formed on a light receiving surface of an image sensor (CCD) 14 via the iris 12. The CCD 14 accumulates the incident light,
The stored charge is read out in synchronization with a timing pulse applied from the timing generator 16. The electric signal read out from the CCD 14 in this manner is amplified by the preamplifier 18 and then applied to the AGC amplifier 20 and the detection circuit 22.

An AGC gain control signal, which will be described later, is added to the AGC amplifier 20. The AGC amplifier 20 amplifies the electric signal with a gain controlled by the AGC gain control signal, and amplifies the amplified electric signal. And output to the detection circuit 26. The video signal processing circuit 24 includes a white balance circuit, a gamma correction circuit, a matrix circuit, an encoder circuit, and the like. The recording device 28 includes a recording circuit,
Here, after converting the video signal into a recording signal suitable for magnetic recording, the recording signal is magnetically recorded on a recording medium such as a video tape via a magnetic head.

On the other hand, a detection circuit 22 for inputting an electric signal from the preamplifier 18 detects the input signal and
0, the integration circuit 30 integrates the input signal for one field, and outputs the integrated value to the iris drive circuit 32 as an average photometric value. A standard setting value for iris is set in the iris driving circuit 32 in advance. The iris driving circuit 32 compares the standard setting value for iris with the average photometric value, and the average photometric value is higher than the standard setting value for iris. If it is larger, it is determined that the iris 12 is too bright, and the iris 12 is driven in the closing direction. On the other hand, if the average photometric value is smaller than the iris standard setting value, it is determined that it is too dark, and the iris 12 is opened. Drive.

Similarly, a detection circuit 26 for inputting an electric signal from the AGC amplifier 20 detects an input signal and outputs the detected signal to an integration circuit 34. The integration circuit 34 integrates the input signal for one field and integrates the integrated value. To the AGC control circuit 36. AGC standard setting value is set in advance in the AGC control circuit 36. The AGC control circuit 36 compares the AGC standard setting value with the integral value, and when the integral value is larger than the AGC standard setting value. Is determined to be too bright, and the AGC amplifier 20
The gain control signal is output to the AGC amplifier 20, while
If the integrated value is smaller than the standard setting value for AGC, it is determined that it is too dark, and an AGC gain control signal is output to the AGC amplifier 20 so as to increase the gain of the AGC amplifier 20.

An exposure correction signal is added to each of the iris drive circuit 32 and the AGC control circuit 36, and the iris standard setting value and the AGC standard setting value are corrected by the exposure correction signal. That is, a signal corresponding to the degree of opening of the iris 12 is applied from the Hall element 40 to the exposure calculation circuit 38 via the Hall element amplifier 42, and the signal A output from the AGC control circuit 36
A GC gain control signal has been added. Exposure calculation circuit 3
8 is a signal corresponding to the degree of opening of the iris 12,
An exposure corresponding to the brightness of the subject is calculated from the AGC gain control signal. The smaller the opening of the iris 12, the brighter the subject, and the greater the gain by the AGC gain control signal, the darker the subject.

A correction amount calculation circuit 44 calculates an exposure correction amount for a standard set value from a signal indicating exposure inputted from the exposure calculation circuit 38, and outputs an exposure correction signal indicating the correction amount to the iris drive circuit 32 and the AGC control circuit 36. And increase or decrease each standard setting. The input / output characteristics of the correction amount calculation circuit 44 are, for example, as shown in the graph of FIG. In the figure, the maximum value of the correction amount is ± 0.3 EV to ± 0.3 EV.
It is 0.5 EV, and the transient correction amount from the state of the correction amount 0 to the maximum correction amount gradually changes according to the brightness of the subject.

By correcting the standard setting value according to the brightness of the subject as described above, a bright subject can be photographed relatively bright, and a dark subject can be photographed relatively dark, and the photographing can be more closely sensed by human eyes. Becomes possible. The first
The correction is not limited to the case where the standard setting value is corrected both when the brightness of the subject is brighter than usual and when the brightness of the subject is darker as in the embodiment. [Second Embodiment] FIG. 3 is a block diagram of a video camera including a second embodiment of an exposure control device for a video camera according to the present invention.

In the first embodiment shown in FIG. 1, the standard set value of the exposure control is corrected in accordance with the brightness of the subject. In the second embodiment, the abnormal light is corrected in accordance with the brightness of the subject. Is limited. FIG.
The same reference numerals are given to the parts common to the first embodiment shown in FIG. In FIG.
A low-pass filter (hereinafter, referred to as LPF) 100 that inputs an electric signal from the preamplifier 18 detects the input signal into a signal indicating a luminance signal. A / D converter 102 is LPF
The luminance signal that has passed through 100 is converted into a digital signal, and the converted luminance data is output to the screen center integration circuit 104 and the entire screen integration circuit 106.

A window signal indicating the timing at which the window signal generating circuit 108 outputs the luminance data of the central portion of the screen (the range indicated by the broken line in FIG. 4) in one field is added to the screen central portion integrating circuit 104. On the basis of the window signal, the screen center integration circuit 104 integrates only the brightness data at the center of the screen in one field among the input brightness data, and divides the integrated data by the area in the range indicated by the broken line in FIG. MPU for partial average luminance data I ₁
(Microprocessor unit) 110.

Similarly, a window signal indicating the timing at which luminance data of substantially the entire screen (in the range of the dashed line in FIG. 4) is output from the window signal generating circuit 108 is added to the entire screen integrating circuit 106. , the entire screen integrating circuit 106 by the window signal, approximately 1 integrated field of luminance data to be input, the entire portion average luminance data I ₂ obtained by dividing the area in the range of one-dot chain line in FIG. 4 and the integrated data to MPU110 Output.

A signal corresponding to the opening of the iris 12 is input from the Hall element 40 to another input of the MPU 110 via the Hall element amplifier 42 and the A / D converter 44.
2 and the AGC gain control signal output from the AGC control circuit 36 is A / D
It is added as AGC gain data via a converter 112.

The MPU 110 receives the input luminance data I ₁ ,
The I ₂ , the opening degree data of the iris 12, and the AGC gain data are processed based on a program stored in a ROM (read only memory) 114 and a look-up table described later, and are processed via D / A converters 116 and 118. Each outputs an exposure correction signal and a drive speed control signal.

That is, the MPU 110 first finds the logarithm of the ratio of the central average luminance data I ₁ and the overall average luminance data I ₂ , D = log (I ₁ / I ₂ ). Also, the opening degree data of the iris 12 and the AGC
A value is calculated by taking the logarithm of the absolute value of the brightness of the subject from the gain data.

[0027] Then, the absolute value | D | if exceeds the threshold Th _D is a so that the center-weighted metering (exposure control mode that emphasizes the central section of the screen), the exposure correction signal D / A converter 116 The exposure correction signal is output to the iris drive circuit 32 and the AGC control circuit 36 via the iris drive circuit 32, and the exposure correction signal is limited according to the calculated brightness of the subject so that the exposure correction amount falls within the range of FIG. That is, as shown in FIG. 5, when the brightness of the subject increases, the amount of spot light correction with respect to the average photometric value decreases, and when the brightness decreases, the amount of backlight correction with respect to the average photometric value decreases.

Thus, when the luminance distribution in the subject screen is in a backlight or spotlight illumination state, the exposure correction is performed so that the center of the screen is appropriate, but the correction amount is corrected for extremely bright abnormal light. Is reduced to prevent the image from becoming too bright, and the surroundings can be prevented from becoming too bright due to excessive backlight correction when an extremely dark subject is photographed.

When the correction amount is reduced as described above,
To gradually decrease the correction amount according to the brightness of the subject.
Change, which results in a natural image without sudden exposure changes.
An image is obtained. | D | ≦ Th_Dof
In this case, the metering will be averaged and the exposure compensation signal will be a standard value.
You. The MPU 110 performs the above-described exposure correction and updates
To the central average luminance data I ₁And average brightness data
I_TwoAre compared before and after a predetermined time has elapsed. And that
Estimate how the preceding and following shooting scenes have changed.

That is, as shown in FIG. 6, for the central average luminance data I ₁ and the overall average luminance data I ₂ , T ₀
The absolute value symbol is A, where I ₁₀ and I ₂₀ are the values at the time point, and I ₁₁ and I ₂₁ are the values at the time point T ₁ after ΔT.
Expressed in _{BS, K 1 = ABS (I} 11 -I 10) K 2 = ABS value of (I ₂₁ -I ₂₀₎ is determined, the threshold Th ₁ for these values respectively, Th
Compared to ₂ . The comparison results are classified as shown in Table 1 below. Note that when | D ₀ |> Th _D , this corresponds to the fact that the exposure control was performed by center-weighted photometry at the time of T ₀ , and | D ₀ |
_{The case of 0} | ≦ Th _D corresponds to the fact that exposure control by average photometry has been performed. Table 1 is stored in the ROM 114 as a look-up table.

When these conditions are actually associated with the photographic scene before and after ΔT, the condition: only the background changes; the main subject is moved; the switching of the photographic scene; Condition: Only the background changes. Condition: The main subject moves to the center of the screen. Condition: Switching of the shooting scene. Condition: It can be estimated that there is almost no change. The sub-classification of the conditions is as follows: "| D ₁ |> | D ₀ |", condition A, "| D ₁ |
> | D ₀ | ”, the condition B is satisfied. As the case where the condition A is satisfied, for example, a scene in which the main subject has moved to the center of the screen is assumed.

After performing the above arithmetic processing, the MPU 110 estimates the state of the photographic scene around the time ΔT and changes the operation speed of the exposure / gain control. That is, the operation speed of the iris 12 and the AGC amplifier 20 is reduced when the shooting scene is determined to be the condition, B,..., And the iris 12 and the AGC are determined when the shooting scene is determined to be the condition A. Amplifier 2
0 to the iris drive circuit 32 via the D / A converter 118 so as to increase the operation speed of the iris drive circuit 32.
And outputs it to the AGC control circuit 36. Note that the drive speed control signal is a control signal such as how many EVs can be moved in one second. For example, the operation speed is high when the speed is 10 EV / second, and when the speed is 0.5 EV / second. The operating speed is slow.

The operation of the exposure control device for a video camera constructed as described above will be described with reference to the flowchart shown in FIG. Exposure / gain control is started by the start of recording, and at the same time, the central part average luminance data I ₁ and the whole part average luminance data I ₂ are subjected to divided photometry. The first exposure and gain control by averaging metering is performed based on the entire portion average luminance data I _2. In this case, the exposure correction signal is not output from the MPU 110, and thus the adjustment is made so that the total amount of light received by the CCD 14 is constant. In this case, a high-speed signal is output from the MPU 110 as a drive speed control signal. As described above, when the recording is started, the exposure and the gain are instantaneously adjusted in the average metering mode, so that the exposure amount of the main subject can be prevented from being extremely inappropriate.

Subsequently, the value of D is calculated and compared with the value of Th _D. When “| D |> Th _D ”, the central part average luminance data I ₁ and the whole part average luminance data I ₂ are largely different, and there is a high probability that the main subject is located at the central part of the screen. In consideration of this, when exposure control is performed in the average photometry mode as it is, the exposure amount of the main subject often becomes inappropriate. Therefore, "| D |>
When it is determined that Th _D ", together with the flag F _C is set indicating the transition to the center-weighted metering mode,
The exposure correction signal corresponding to the central average luminance data I ₁ is MP
A driving speed control signal output from the U 110 via the D / A converter 116 and increasing the operation speed is output from the MPU 110
Through the D / A converter 118. In addition, "|
When D | ≦ Th _D ”, the average photometry mode is maintained as it is.

After the exposure / gain control is performed in this manner,
ΔT is the time after which division photometry performed again, relative to the total portion average luminance data I ₂₀ and the central portion average luminance data I ₁₀ obtained in the previous segment metering, new central portion average brightness as shown in FIG. 6 data I ₁₁ and the entire portion average luminance data I ₂₁ is detected. Then, from the absolute value of the difference between the respective luminance data, K
Value of ₁ and K ₂ are determined. The values of K ₁ and K ₂ are compared with respective threshold values Th ₁ and Th ₂ and classified according to Table 1 described above. Further, the ΔT time is set to CCD1.
4 can be made to coincide with the field readout cycle. In this case, it is not necessary to provide a separate timer for measuring ΔT.

When the values of K ₁ and K ₂ are obtained in this way,
Before and after the elapse of the ΔT time, the state of the shooting scene is estimated. Under the center-weighted metering mode, when the condition, that is, both the center average luminance data I ₁ and the whole-part average luminance data I ₂ greatly changed, the shooting scene was switched by, for example, panning a video camera greatly. Therefore, after canceling the center-weighted metering mode, the exposure / gain control is restarted in the average metering mode for a new scene.

In the case where only the central portion average luminance data I ₁ largely changes, the whole portion average luminance data I ₂ does not change much and | D ₁ |> | D ₀ | a scene as the main subject has moved to the center of the screen at the time, high-speed exposure-gain control on the basis of the central portion average luminance data I ₁₁ that is newly detected while the center-weighted metering mode in this case Let me do it. still,
Central part average luminance data I ₁ , whole part average luminance data I ₂
If both of them hardly change, it means that the same scene with the same luminance distribution is being shot continuously, so that the center-weighted metering mode is continued and the exposure / gain control is performed at high speed. You should let it.

In conditions other than the condition A and the condition in the center-weighted metering mode or the conditions in the average metering mode, the main subject is moving in the subject screen shown in FIG. By panning the video camera in accordance with the movement of the subject, it is estimated that the scene is a scene in which only the luminance changes in the background. In such a case, the MPU 110 outputs a drive speed control signal for reducing the operation speed of the exposure / gain control via the D / A converter 118. Thus, both the iris drive circuit 32 and the AGC control circuit 36 operate slowly, and the exposure amount of the main subject does not change rapidly.

As described above, when continuity is recognized in the photographic scene, the operation speed of the exposure / gain control is set to be lower than the exposure / gain control at a high speed following the change in the luminance of the background. The exposure amount is stabilized.
Of course, by performing such control, background depiction is sacrificed to some extent, but in a continuous scene, maintaining a stable exposure of the main subject provides a natural-looking image during image reproduction.

The determination of the continuity of the photographic scene is not limited to the above embodiment, but may be performed based on a spatial frequency component in the luminance signal. For example, BFP with when focusing is performed, the pass bandwidth of the 600KH _Z ~2.4MH _Z is a spatial frequency component having the general subject
(Band pass filter) is replaced with the LPF 100 in FIG.
Is used in place of
4, the continuity of the shooting scene can be determined. That is, the auto-focusing device mounted on the video camera sets an area close to an area surrounded by a broken line in the center of the screen shown in FIG. 4 as a distance measurement area, and the photographing lens 10 focuses on this area. Is going. Since the BPF allows spatial frequency components that increase during focusing to pass through, the output data from the center-of-screen integrating circuit 104 is an integrated value of the spatial frequency components in the focused area.

By comparing the integrated value of the spatial frequency component before and after the ΔT time as described above, when there is a large change, it can be estimated that the object to be measured, that is, the main subject has changed. Therefore, in this case, the operating speed of the exposure / gain control may be increased, and when the integrated value of the spatial frequency component does not change much, the operating speed of the exposure / gain control may be reduced.

If the angle of view of the taking lens 10 is θ, the size of the main subject in one direction in the subject screen is L, and the distance to the main embodiment is X, L∝1 / (tan θ · X ) There is a relationship. Therefore, this value of L is used as the amount of change, and ΔT
It is also possible to presume that a scene change has occurred when the change has changed beyond a predetermined range before and after the time.

Incidentally, even if the video camera itself maintains the same attitude, the brightness distribution in the screen may greatly change due to zooming. In such a case, it is natural that the scene is substantially switched.
It is preferable to increase the operation speed of the exposure / gain control. In this case, the switching of the scene can be determined by detecting a temporal change amount of the zoom position of the photographing lens 10.

In the second embodiment, the exposure correction amount is reduced when the brightness of the subject becomes high or low. However, the present invention is not limited to this. Only the exposure correction amount may be reduced, or the exposure correction amount may be reduced only when the brightness of the subject becomes low. Further, the exposure control device for a video camera according to the present invention can be applied not only to a video movie camera but also to an electronic still video camera.

[0045]

As described above, according to the exposure control apparatus for a video camera according to the present invention, the standard setting value targeted for the exposure control is corrected according to the brightness of the subject. A bright and dark subject can be photographed relatively darkly, and a photographing closer to the sensation seen by human eyes can be performed.

When the brightness distribution in the subject screen is in a backlight or spotlight illumination state, the exposure correction is performed so that the center of the screen becomes appropriate. When the spot light correction amount is reduced and the brightness of the subject is lowered, the backlight correction amount in the exposure correction amount is reduced, so that the surroundings become darker by reducing the correction amount for extremely bright abnormal light. It is possible to prevent the surroundings from becoming too bright due to excessive backlight correction when an extremely dark subject is photographed. Further, when the correction amount is reduced as described above, the correction amount is changed so as to gradually decrease in accordance with the brightness of the subject, whereby a natural image without a rapid change in exposure can be obtained. Further, since only the absolute luminance is used for the correction for the extraordinary light, there is an advantage that it does not depend on the photometric pattern or the focus position, and is not affected by the clip level of the high luminance clip circuit.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video camera including a first embodiment of a video camera exposure control apparatus according to the present invention.

FIG. 2 is a graph illustrating an example of a correction amount of a standard setting value for the brightness of a subject.

FIG. 3 is a block diagram of a video camera including a second embodiment of the video camera exposure control apparatus according to the present invention.

FIG. 4 is an explanatory diagram illustrating an example of a subject screen.

FIG. 5 is a graph showing a range of an exposure correction amount with respect to the brightness of a subject.

FIG. 6 is a graph showing an example of a fluctuation of a photometric value in each photometric area.

FIG. 7 is a flowchart used to explain the operation of the embodiment shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Photographing lens 12 ... Iris 14 ... Image sensor (CCD) 18 ... Preamplifier 20 ... AGC amplifier 22, 26 ... Detection circuit 24 ... Video signal processing circuit 30, 34 ... Integrating circuit 32 ... Iris drive circuit 36 ... AGC Control circuit 38 Exposure calculation circuit 40 Hall element 44 Correction amount calculation circuit 100 LPF 104 Screen center integration circuit 106 Overall screen integration circuit 108 Window signal generation circuit 110 MPU

Claims (6)

(57) [Claims] 1. An exposure for a video camera which controls at least one of an incident light amount incident on an imaging device from an imaging lens via an iris and a signal level of an electric signal converted by the imaging device to a standard setting value. In the control device, a detection unit that detects the brightness of the subject, and a correction unit that corrects the standard setting value in a direction in which the image is captured brighter when the brightness of the subject detected by the detection unit is brighter than normal. An exposure control device for a video camera, comprising: 2. An exposure for a video camera which controls at least one of an incident light amount incident on an imaging device from an imaging lens via an iris and a signal level of an electric signal converted by the imaging device to a standard setting value. In the control device, detecting means for detecting the brightness of the subject, and correcting means for correcting the standard setting value in a direction of shooting darker when the brightness of the subject detected by the detecting means is darker than usual, An exposure control device for a video camera, comprising: 3. An exposure for a video camera for controlling at least one of an incident light amount incident on an imaging device from an imaging lens via an iris and a signal level of an electric signal converted by the imaging device to a standard setting value. In the control device, detection means for detecting the brightness of the subject, and when the brightness of the subject detected by the detection means is brighter than normal, the standard setting value is corrected in a direction in which the subject is brightly photographed, and An exposure control device for a video camera, comprising: a correction unit that corrects the standard setting value in a direction in which the image is darkened when the brightness is lower than usual. 4. An exposure for a video camera which controls at least one of an incident light amount incident on an image pickup device from an image pickup lens via an iris and a signal level of an electric signal converted by the image pickup device to a standard set value. A control unit that calculates an exposure correction amount based on a luminance signal indicating a subject image, and corrects the standard setting value according to the exposure correction amount; a detection unit that detects brightness of the subject; An exposure control device for a video camera, comprising: an exposure correction amount limiting unit that reduces the spot light correction amount in the exposure correction amount when the brightness of the subject detected by the unit increases. 5. An exposure for a video camera for controlling at least one of an incident light amount incident on an image pickup device from an image pickup lens via an iris and a signal level of an electric signal converted by the image pickup device to a standard setting value. A control unit that calculates an exposure correction amount based on a luminance signal indicating a subject image, and corrects the standard setting value according to the exposure correction amount; a detection unit that detects brightness of the subject; An exposure control device for a video camera, comprising: an exposure correction amount limiter configured to reduce a backlight correction amount in the exposure correction amount when the brightness of a subject detected by the means is reduced. 6. An exposure for a video camera for controlling at least one of an incident light amount incident on an image sensor through an iris from a photographing lens and a signal level of an electric signal converted by the image sensor to a standard setting value. A control unit that calculates an exposure correction amount based on a luminance signal indicating a subject image, and corrects the standard setting value according to the exposure correction amount; a detection unit that detects brightness of the subject; Exposure correction amount limiting means for reducing the amount of spot light correction in the exposure correction amount when the brightness of the subject detected by the means increases, and reducing the backlight correction amount in the exposure correction amount when the brightness of the subject decreases. An exposure control device for a video camera, comprising: