JPH09186916A - Imaging device - Google Patents

Abstract

(57) [Summary] [Purpose] An imaging device capable of exposure control in response to a wide range of subject illuminance. [Structure] A diaphragm mechanism means 2 for controlling incident light from a zoom lens 1, a diaphragm detecting means 5, a transmittance variable filter means 6 for changing the light transmittance of incident light 6, a transmittance detecting means 8, an image sensor 9, and a signal. The signal processing means 1 has a processing means 13 and a microcomputer 15 including an exposure correction means.
The subject exposure data is detected by 3, and the diaphragm mechanism means 2,
The microcomputer 15 performs exposure correction by controlling the operation of the variable transmittance filter 6 and the image sensor 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of imaging devices.

[0002]

2. Description of the Related Art The structure and operation of a conventional image pickup apparatus will be described with reference to the block diagram of FIG.

In the structure of the image pickup apparatus shown in FIG. 9, 1 is an image forming lens group for forming an image of a subject, 2 is a diaphragm mechanism unit having a diaphragm blade structure for controlling the amount of incident light, and 3 is a diaphragm mechanism unit 2. Drive motor, 4 is an aperture mechanism drive means for driving the drive motor 3, 5 is an aperture detection means for detecting the state of the aperture mechanism means 2, 9 is an image sensor for photoelectrically converting incident light, and 10 is an image sensor 9. An image pickup device driving means for controlling and reading out the photoelectrically converted signal and controlling a so-called electronic shutter function for controlling the signal storage time, 11 samples the signal photoelectrically converted by the image pickup device 9 and electrically outputs the signal. CDS / AGC means for performing automatic gain control (hereinafter referred to as AGC) for amplification, and 12 for converting an analog signal output from the CDS / AGC means 10 into a digital signal. Analog - digital converter (hereinafter,
A / D conversion) means, 13 is a camera signal processing means for generating a standard television signal by adding a sync signal after performing processing such as gamma correction, color separation, and color difference matrix, and 14 is a camera signal processing means 13 Digital-to-analog conversion (hereinafter referred to as D / A conversion) means for converting the output signal from the digital signal state into an analog signal, 16 is the diaphragm mechanism 2, the electronic shutter function of the image sensor 9, and the CDS.
/ AGC is a microcomputer provided with an exposure control means for controlling the AGC of the means 11 to control the exposure.

In the image pickup apparatus having the above-mentioned structure, in order to obtain an optimum image by a simple photographing operation, the time-varying brightness state of the subject being photographed is automatically optimized. There is an automatic exposure control means.

Next, the automatic exposure control means will be described.

The automatic exposure control means is controlled by the exposure control means of the microcomputer 16 according to the control flow chart shown in FIG. First, in exposure data detection step S501, a change in the brightness of the subject is detected from the video signal of the signal processing means 13. In the exposure state detection step S502, the exposure data detection step S50
It is determined from the signal detected in 1 whether the exposure state is proper, and if it is proper, the current exposure control value is output as it is. If it is not proper, the diaphragm mechanism means 2 and the CDS / AGC means 11
The AGC is controlled to select the exposure control parameter and calculate the exposure correction amount for each parameter according to the detection signal of the exposure data detection step S501.

Here, a case where the exposure control is performed according to the program diagram shown in FIG. 11 will be described as an example. In photography (area B) under sufficient illuminance such as outdoors, the AGC gain is fixed to the minimum gain, and the control amount of the diaphragm mechanism means 2 according to the signal detected in the exposure data detection step S501 is calculated in the control value calculation step S506. Ask in. When the brightness of the subject becomes dark and the diaphragm mechanism unit 2 is opened (area A) and the diaphragm mechanism unit 2 cannot be controlled, the diaphragm mechanism state is fixed to the open state, and the AG corresponding to the brightness of the subject is displayed.
The control amount of the C gain is obtained in the control value calculation step S504. The control value of each parameter obtained in this way is output in the control value output step S507, and by updating the control value, control is performed so as to always follow the brightness of the subject and achieve the optimum exposure state.

In the exposure control according to the program diagram of FIG. 11 described above, the exposure control is performed by the aperture mechanism means 2 when photographing with sufficient illuminance such as outdoors, but the aperture mechanism means 2 has a small aperture especially when photographing an object with high illuminance. However, there is a problem that a diffraction phenomenon occurs and the image quality deteriorates. This problem may occur during general outdoor shooting as performance improvement such as sensitivity increase of the image sensor 9 and miniaturization due to the recent technological progress, and the deterioration of image quality becomes remarkable. It was Therefore, there has been conventionally devised an image pickup apparatus in which a transmittance variable filter means for controlling the light transmittance of incident light is used in combination with the diaphragm means 2 for exposure control.

Next, the exposure control of the image pickup device using the variable transmittance filter means will be described.

FIG. 12 is a block diagram showing the structure of an image pickup apparatus using variable transmittance filter means. The parts different from FIG. 9 are variable transmittance filter means 6 for controlling the light transmittance of incident light, and the transmittance. A transmittance variable filter driving unit 7 for driving the variable filter unit 6 is added, and the microcomputer 17 is provided with a function of controlling exposure using the transmittance variable filter unit 6.

The exposure control of the microcomputer 17 is controlled according to the control flow chart of FIG. 13, and the control is performed according to the program diagram of FIG.
AGC gain and transmittance variable filter means 6 of means 11
Control.

Next, the control flow chart of FIG. 13 and FIG.
The operation will be described with reference to the program diagram of FIG.

Photographing under sufficient illuminance such as outdoors (see FIG. 14).
Area B), the AGC gain is fixed to the minimum gain, the transmittance variable filter means 6 is fixed to the maximum transmittance state (100% is shown in FIG. 14), and the signal detected in the exposure data detection step S601 is used. According to the diaphragm mechanism means 2
The control amount of is calculated in the control value calculation step S609. When the brightness of the subject becomes dark and the diaphragm mechanism unit 2 is opened (area A) and cannot be controlled by the diaphragm mechanism unit 2, the diaphragm mechanism unit 2 is opened and the variable transmittance filter unit 6 is fixed. The control amount of the AGC gain according to the brightness of is calculated in the control value calculation step S604.

On the contrary, when the brightness of the subject in which the diaphragm mechanism means 2 is in the small diaphragm state is high illuminance (area C), the AGC gain is the minimum gain, and the diaphragm mechanism means 2 is the small diaphragm so that the diffraction phenomenon does not occur. The state is fixed, and the transmittance of the variable transmittance filter means 6 is calculated in the control value calculation step S607 according to the signal detected in the exposure data detection step S601. The control value of each parameter obtained in this way is output in the control value output step S610, and the control value is updated so as to always follow the brightness of the subject so as to achieve the optimum exposure state.

As described above, when a subject of high illuminance in which the aperture mechanism means 2 is in a small aperture state is photographed, exposure control is performed by using the variable transmittance filter means 6, thereby preventing a diffraction phenomenon from occurring and deteriorating the image quality. It is possible to perform exposure control according to the brightness of the subject without being accompanied.

[0016]

However, in the variable transmittance filter means, the responsiveness deteriorates as the light transmittance decreases, and control accuracy is required. Therefore, the light transmittance is lowered to control the exposure. Things are tough. Therefore, the light amount control range that can be controlled by the transmittance variable filter means is narrow, and the following range is required for optimal exposure control by following the change in the brightness of the object only with the transmittance variable filter means when shooting a subject with high illuminance. It is too narrow to handle various shooting situations.

According to the present invention, it is possible to prevent deterioration of image quality due to the diffraction phenomenon of the lens, and to perform smooth exposure control by following the brightness of the subject even in various shooting situations, so that an optimum image can be obtained. An object is to provide a possible imaging device.

[0018]

Therefore, the image pickup apparatus according to the present invention comprises: (1) an image forming lens for forming an image of a subject, and an image pickup element for photoelectrically converting light incident from the image forming lens. A diaphragm mechanism means for limiting the amount of light incident on the image sensor provided in the optical path of the imaging lens, and light transmission of light incident on the image sensor provided on the optical path of the imaging lens. Transmittance variable filter means for changing the rate, light transmittance detecting means for detecting the light transmittance of the transmittance variable filter means, and a video signal which is processed into a signal photoelectrically converted by the image pickup device and becomes a television signal. An image pickup apparatus comprising: a signal processing unit that generates a signal; and an exposure control unit that optimally controls an exposure state of the generated video signal, wherein the exposure control unit controls the transmittance variable filter unit. The variable light transmittance range is limited, and the light amount of the subject incident on the image pickup device is controlled by the diaphragm mechanism means until the diaphragm state of the diaphragm mechanism means reaches a predetermined value on the small diaphragm side. When the diaphragm state reaches a predetermined value on the small diaphragm side, the light transmittance of the transmittance variable filter means is controlled within the limit range according to the light amount of the subject incident on the image sensor, and the transmittance variable filter means When the transmittance of the light is changed according to the amount of light of the subject incident on the image sensor, the diaphragm mechanism means is fixed to a predetermined value on the small diaphragm side or a state near the predetermined value, and the light transmittance detecting means When the amount of light of the subject which exceeds the limit value on the side where the light transmittance of the variable transmittance filter means detected by the above-mentioned method is incident on the image pickup device, the light transmittance of the variable transmittance filter means is lowered. Of fixed the limit value, the image pickup apparatus, characterized by exposure control by controlling the aperture state of the iris mechanism unit in accordance with the amount of the subject incident on the image pickup device.

(2) An image forming lens for forming an image of a subject, an image pickup device for photoelectrically converting light incident from the image forming lens, and the image pickup device provided in the optical path of the image forming lens. A diaphragm mechanism means for limiting the amount of incident light, a transmittance variable filter means for changing the light transmittance of light incident on the image pickup device provided on the optical path of the imaging lens, and the transmittance variable filter means. , A light transmittance detecting means for detecting the light transmittance of the image sensor, an electronic shutter means for controlling the accumulation time of the signal of the image sensor, and a video signal which becomes a television signal by processing the signal photoelectrically converted by the image sensor. An image pickup apparatus comprising: a signal processing unit that generates an exposure state of the generated video signal; and an exposure control unit that optimally controls an exposure state of the generated video signal. Limit the range of light transmittance that can be varied by means for controlling the amount of light of the subject incident on the image sensor by the diaphragm mechanism means until the diaphragm state of the diaphragm mechanism means reaches a predetermined value on the small diaphragm side, When the aperture state of the aperture mechanism means reaches a predetermined value on the small aperture side, the aperture mechanism means is fixed to a predetermined value on the small aperture side or a state in the vicinity of the predetermined value, and the transmittance variable filter means or the electronic shutter means One of the means is used to control the amount of light of the subject that enters the image sensor, and when the amount of light of the subject that exceeds the control limit value is incident on the image sensor, the other means causes the image sensor to enter the image sensor. When the light quantity of the incident subject is controlled, and further, the transmittance variable filter means and the electronic shutter means both reach the control limit value, when the light quantity enters the image sensor, The imaging apparatus whose serial in accordance with the amount of the subject entering the imaging element, characterized in that the exposure control by controlling the aperture state of the iris mechanism unit, is to achieve the above object.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image pickup apparatus according to the present invention is characterized by including means for performing exposure control by using a transmittance variable filter means and an exposure control function such as an aperture mechanism means and an electronic shutter means in combination. It is implemented according to the configuration.

With the above construction, it is possible to prevent the image quality from being deteriorated due to the diffraction phenomenon of the lens, and to perform the smooth exposure control by following the brightness of the subject even under various photographing situations, so that it can be applied to various subjects and photographing situations. It is possible to obtain the optimum image according to the condition.

[0022]

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

(First Embodiment) FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. The portions denoted by the same reference numerals as those in the conventional example have the same functions as those in the conventional example, and the process of processing the video signal is the same. In this embodiment, the transmission for detecting the transmittance of the variable transmittance filter means 6 is detected. Rate detection means 8 is added.

Unlike the conventional example, the microcomputer 15 of the first embodiment of the present invention performs the exposure control shown in the program diagram of FIG. 3 as the internal processing according to the control flow chart shown in FIG. Since control of the variable transmittance filter means 6 becomes stricter as the transmittance becomes lower, the transmittance is detected by the transmittance detecting means 8 and the upper limit value and the lower limit value are set in advance by the microcomputer 15 to be limited. Exposure is controlled within the range of transmittance. FIG. 3 shows a case where the transmittance of the variable transmittance filter means is varied between 100% and 20%.

Next, the operation of the exposure control means of the first embodiment of the present invention will be described with reference to the control flowchart of FIG. 2 and the program diagram of FIG.

First, in the exposure data detection step S101, the change in the brightness of the subject is detected from the video signal of the signal processing means 13. It is determined whether or not the exposure state is proper from the signal detected in the exposure data detection step S101 (S10).
2) If it is proper, the current exposure control value is output as it is, and if it is not proper, exposure data detection step S101.
The exposure control parameter is selected and the exposure correction amount for each parameter is calculated based on the detection signal of. In the first embodiment, the diaphragm mechanism means 2, the variable transmittance filter means 6,
The AGC gain of the CDS / AGC means 11 is used to control the exposure control parameter selection and the exposure correction amount for each parameter as shown in the program diagram of FIG.

In a general outdoor subject brightness as shown by area B in FIG. 3, a control value calculation step S is performed.
At 112, the AGC gain is fixed to the minimum gain, and the variable transmittance filter means 6 is fixed to the maximum transmittance state, and the control value of the diaphragm mechanism means 2 corresponding to the signal detected in the exposure data detection step S101 is obtained (S112). Exposure control is performed by changing the diaphragm state according to the brightness of the subject and controlling the amount of light incident on the image sensor.

At the time of photographing an object of low illuminance in the area A where the diaphragm mechanism means 2 is in the open state, the diaphragm mechanism means 2 is in the open state and the transmittance variable filter means 6 is in the maximum transmittance in the control value calculation step S104. Fixedly, the AGC gain according to the signal detected in the exposure data detection step S101 is obtained, and the exposure control according to the brightness of the subject is performed by the AGC.

The microcomputer 15 sets the small aperture limit value to a state where the diffraction phenomenon does not occur on the small aperture side of the aperture mechanism means 2, and the aperture detection means 5 sets the aperture mechanism means 2
If the aperture mechanism means 2 detects the aperture state of No. 2 and is in the small aperture state where the aperture value reaches the small aperture limit value (area C), the AGC gain is set to the minimum gain in the control value calculation step S110, and the aperture mechanism is set. The means 2 fixes the small aperture limit state, obtains the light transmittance of the transmittance variable filter means according to the signal detected in the exposure data detection step S101, and performs the exposure control according to the brightness of the subject.

Further, when the subject is photographed at a high illuminance (area D) such that the transmittance of the variable transmittance filter means 6 whose brightness is detected by the transmittance detecting means 8 reaches the lower limit value, control is performed. In the value calculation step S108, the AGC gain is fixed to the minimum gain, the transmittance of the transmittance variable filter unit 6 is fixed to the lower limit value, and the exposure data detection step S101.
The control value of the diaphragm mechanism means 2 is obtained according to the signal detected in step 1, and the exposure is controlled in accordance with the brightness of the subject by further narrowing the diaphragm state to a value smaller than the small diaphragm limit value.

With the above configuration and control, it is possible to obtain the optimum image by exposure control corresponding to a wide range of illuminance of the subject.

(Second Embodiment) The configuration of the second embodiment of the present invention is the same as that of the first embodiment, only the exposure control means inside the microcomputer 15 of FIG. 1 is different. 4 shows a control flowchart of the second embodiment, and FIG. 5 shows a program diagram of the second embodiment.

Next, the operation of the exposure control means, which is a feature of the second embodiment, will be described with reference to the control flowchart of FIG. 4 and the program diagram of FIG.

In the second embodiment of the present invention, the electronic shutter means is also used for the exposure control, but like the first embodiment, the aperture mechanism means 2 is used in the microcomputer of the second embodiment.
The small aperture limit value is set so that the diffraction phenomenon does not occur on the small aperture side, and the aperture detection means 5 detects the aperture state of the aperture mechanism means 2 so that the brightness of the subject is determined by the aperture mechanism means 2 as described above. In area A, area B, and area C shown in FIG. 5 until the small aperture state reaches the small aperture limit value, the speed setting of the electronic shutter is fixed to 1/60 (in the case of NTSC), and The parameters controlled according to the brightness operate in the same manner as in the first embodiment.

Next, at the time of photographing a subject with high illuminance (area D) such that the transmittance of the variable transmittance filter 6 detected by the transmittance detector 8 reaches the lower limit value, a control value calculation step S211 is performed. Then, the AGC gain is the minimum gain, the transmittance of the variable transmittance filter unit 6 is fixed to the lower limit value, and the diaphragm mechanism unit is fixed to the small diaphragm limit value, and the speed value of the electronic shutter corresponding to the signal detected in the exposure data detection step S201. Then, the electronic shutter speed is varied to perform exposure control according to the brightness of the subject.

Further, the electronic shutter speed is the maximum value (1/1 in FIG. 5) preset by the microcomputer.
When a bright subject such as 2,000 seconds is shown (area E), the control value calculation step S20
In FIG. 9, the AGC gain is fixed to the minimum gain, the transmittance of the variable transmittance filter unit 6 is fixed to the lower limit value, and the electronic shutter speed is fixed to the maximum value, and the diaphragm mechanism unit is controlled according to the signal detected in the exposure data detection step S201. A value is obtained, and the aperture mechanism means is made narrower than the small aperture limit value to perform exposure control according to the brightness of the subject.

As described above, in the second embodiment of the present invention, even when the brightness of the subject reaches the lower limit of the transmittance of the variable transmittance filter means 6, the exposure control is performed by following the brightness of the subject by the electronic shutter. By doing so, it is possible to further prevent the occurrence of the diffraction phenomenon. Further, when a subject with high illuminance is photographed, exposure control is performed by the diaphragm mechanism, so that it is possible to keep an optimum exposure state by following changes in brightness of the subject in a wide range.

(Third Embodiment) The configuration of the third embodiment of the present invention is the same as that of the second embodiment except that the exposure control means inside the microcomputer 15 of FIG. 1 is different. 6 shows a control flowchart of the third embodiment, and FIG. 7 shows a program diagram of the third embodiment.

In the third embodiment, the parameters for exposure control in the areas C and D shown in FIG. 7 are different from those in the second embodiment, and the same effect can be obtained.

In each of the first, second, and third embodiments, the number of parameters that can be changed according to the brightness of the subject in each area of the brightness of the subject is limited to one. The exposure control may be performed by using a plurality of parameters that are changed according to the brightness of the subject when the area changes as shown in FIG.

[0041]

As described above, according to the first invention of the present application, the diaphragm mechanism means for limiting the amount of light incident on the image pickup device provided in the optical path of the imaging lens, and the incident light on the image pickup device. The variable transmittance filter means for changing the light transmittance of the light, and the light transmittance detecting means for detecting the light transmittance of the variable transmittance filter means, and the diaphragm state of the diaphragm mechanism means on the small diaphragm side. The exposure is controlled by the diaphragm mechanism means until a predetermined value is reached, and when the diaphragm state of the diaphragm mechanism means reaches a predetermined value on the small diaphragm side, the light transmittance of the transmittance variable filter means is controlled within a predetermined limit range. By performing the exposure control in such a manner, it is possible to prevent the diffraction phenomenon that occurs when the diaphragm mechanism means is in the small aperture state, and it is possible to perform the exposure control according to the brightness of the subject while maintaining the optimum image state.

Further, when the amount of light of an object which exceeds the limit value on the side where the light transmittance of the variable transmittance filter means detected by the light transmittance detecting means exceeds the low value, the diaphragm mechanism means is used. With the configuration that controls the exposure, it is possible to provide an imaging device that can perform a smooth exposure control by following the brightness of a subject even in various shooting situations and always obtain an optimum image.

According to the second invention of the present application, the diaphragm mechanism means for limiting the amount of light incident on the image sensor provided in the optical path of the imaging lens, and the light transmittance of the light incident on the image sensor. A variable transmittance filter means for changing the light transmittance, a light transmittance detecting means for detecting the light transmittance of the variable transmittance filter means, and an electronic shutter means for controlling the signal accumulation time of the image pickup device. The exposure control is performed by the aperture mechanism means until the aperture state reaches a predetermined value on the small aperture side, and when the aperture state of the aperture mechanism means reaches the predetermined value on the small aperture side, the variable transmittance filter means and the electronic shutter means are used. By controlling the exposure,
The diffraction phenomenon that occurs when the diaphragm mechanism is in the small diaphragm state can be prevented in a wider range of brightness than in the first aspect of the invention, and the exposure control can be performed while maintaining the optimum image state in the wide range of brightness of the subject. Become.

Further, when the amount of light of the subject such that the transmittance variable filter means and the electronic shutter means exceed the control limit value is incident on the image pickup device, the diaphragm mechanism means controls the exposure, so that it can be used in various photographing situations. It is possible to provide an effect that it is possible to provide an image pickup apparatus that can perform smooth exposure control by following the brightness of a subject and always obtain an optimum image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a control flow chart of the exposure control means of the first embodiment.

FIG. 3 is a program diagram of the exposure control means of the first embodiment.

FIG. 4 is a control flowchart of an exposure control means of the second embodiment.

FIG. 5 is a program diagram of the exposure control means of the second embodiment.

FIG. 6 is a control flowchart of the exposure control means of the third embodiment.

FIG. 7 is a program diagram of the exposure control means of the third embodiment.

FIG. 8 is a program diagram of the exposure control means of another embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of Conventional Example 1.

FIG. 10 is a control flowchart of an exposure control unit of Conventional Example 1.

FIG. 11 is a program diagram of an exposure control unit of Conventional Example 1.

FIG. 12 is a block diagram showing a configuration of Conventional Example 2.

FIG. 13 is a control flowchart of an exposure control unit of Conventional Example 2.

FIG. 14 is a program diagram of an exposure control unit of Conventional Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Object imaging zoom lens 2 Aperture mechanism means 3 Aperture mechanism drive motor 4 Aperture mechanism drive means 5 Aperture detection means 6 Transmittance variable filter means 7 Transmittance variable filter drive means 8 Transmittance detection means 9 Image sensor 10 Image sensor drive Means 11 CDS / AGC means 12 A / D conversion means 13 Signal processing means 14 D / A conversion means 15 Microcomputer of the first embodiment 16 Microcomputer of Conventional Example 1 17 Microcomputer of Conventional Example 2

Claims (2)

[Claims] 1. An imaging lens for forming a subject image,
An image sensor for photoelectrically converting the light incident from the image forming lens, a diaphragm mechanism unit provided in the optical path of the image forming lens for limiting the amount of light incident on the image sensor, and a light for the image forming lens. The variable transmittance filter means for changing the light transmittance of the light incident on the image sensor provided on the road, the light transmittance detection means for detecting the light transmittance of the variable transmittance filter means, and the image sensor An image pickup apparatus comprising: a signal processing unit that processes a photoelectrically converted signal to generate a video signal to be a television signal; and an exposure control unit that optimally controls an exposure state of the generated video signal, The exposure control means limits the light transmittance range that can be varied by the transmittance variable filter means, and the aperture mechanism is manually operated until the aperture state of the aperture mechanism means reaches a predetermined value on the small aperture side. The amount of light of the subject incident on the image sensor is controlled by a step, and when the diaphragm state of the diaphragm mechanism means reaches a predetermined value on the small aperture side, the transmittance variable filter means according to the amount of light of the subject incident on the image sensor. When the light transmittance of the diaphragm is controlled within the limited range, and the transmittance of the transmittance variable filter means is changed according to the light quantity of the subject incident on the image sensor, the diaphragm mechanism means is set to the small diaphragm side. The amount of light of the subject that is fixed to a predetermined value or a state in the vicinity of the predetermined value and exceeds the limit value on the side where the light transmittance of the variable transmittance filter detected by the light transmittance detecting means is low is in the image pickup device. When incident, the light transmittance of the variable transmittance filter means is fixed to a lower limit value, and the diaphragm state of the diaphragm mechanism means is controlled to be exposed in accordance with the light amount of the subject incident on the image sensor. Imaging apparatus characterized by Gosuru. 2. An imaging lens for forming a subject image,
An image sensor for photoelectrically converting the light incident from the image forming lens, a diaphragm mechanism unit provided in the optical path of the image forming lens for limiting the amount of light incident on the image sensor, and a light for the image forming lens. A variable transmittance filter means for changing the light transmittance of light incident on the image sensor provided on the road; a light transmittance detecting means for detecting the light transmittance of the variable transmittance filter means; An electronic shutter means for controlling a signal storage time, a signal processing means for processing a signal photoelectrically converted by the image sensor to generate a video signal to be a television signal, and an exposure state of the generated video signal are optimal. And an exposure control means for controlling the exposure control means, wherein the exposure control means limits a light transmittance range variable by the transmittance variable filter means, and the diaphragm mechanism. Until the aperture state of the means reaches a predetermined value on the small aperture side, the aperture mechanism means controls the amount of light of the subject incident on the image sensor, and when the aperture state of the aperture mechanism means reaches the predetermined value on the small aperture side. The aperture mechanism means is fixed to a predetermined value on the small aperture side or a state near the predetermined value, and one of the transmittance variable filter means and the electronic shutter means is used to detect an object entering the image sensor. When the light quantity of the subject that controls the light quantity exceeds the control limit value is incident on the image sensor, the other means controls the light quantity of the subject that enters the image sensor, and the variable transmittance filter means is further provided. When a quantity of light such that both the electronic shutter means reach a control limit value is incident on the image sensor, the diaphragm mechanism is arranged according to the quantity of light of the subject incident on the image sensor. Imaging device, characterized in that the exposure control by controlling the aperture state of the stage.