JP5906626B2 - Aperture control device and imaging device - Google Patents

Description

  The present invention relates to an aperture control device and an imaging device.

  An imaging apparatus represented by a digital camera generally performs what is called a live view display in which captured through images are sequentially displayed on a display screen. In this live view display, exposure calculation when capturing a through image is repeatedly executed, and exposure control is executed based on the result of the exposure calculation. In view display, a hunting phenomenon with respect to brightness occurs. As a method for suppressing the hunting phenomenon and stabilizing the exposure of the through image, for example, it is proposed to perform exposure control using an EV diagram having hysteresis (see Patent Document 1).

Japanese Patent No. 3496792

  In this patent document 1, the hunting phenomenon is prevented by performing exposure control using an EV diagram having hysteresis and suppressing a change in aperture value. However, in this patent document 1, since exposure control is emphasized, the effective range (settable range) of the aperture value effective in the focus adjustment of the imaging optical system is not considered. For this reason, there exists a fault that the precision in the focus adjustment of an imaging optical system falls.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an aperture control device and an imaging device that can prevent a reduction in accuracy in focus adjustment of an imaging optical system.

To solve the problems described above, aperture control device of the present invention is repeatedly quantity adjusting the aperture retriever of subject light incident, the luminance value based on the subject light more quantity is adjusted to Ri said aperture calculated a photometric calculation unit for repeatedly and calculated exposure calculation unit that performs an exposure operation using the luminance values, the exposure calculation the grain Rino aperture determined by the used for the previous exposure control diaphragm Rino aperture value, and based on the minimum value of the effective range of the diaphragm Rino aperture in the focus adjustment of the imaging optical system includes a diaphragm value setting unit that sets the diaphragm Rino aperture in the next exposure control, and The aperture value setting unit, when the minimum value of the effective range is less than the aperture value of the aperture obtained by the exposure calculation, and is equal to or greater than the aperture value of the aperture used for the previous exposure control, Next exposure control As the aperture value of definitive said aperture, to set the minimum value of the effective range.

Further, the aperture control device of the present invention includes an aperture that adjusts the amount of incident subject light, a photometric calculation unit that repeatedly calculates a luminance value based on the subject light whose amount of light has been adjusted by the aperture, and the repeatedly calculated An exposure calculation unit for performing an exposure calculation using a luminance value; the aperture value of the aperture obtained by the exposure calculation; the aperture value of the aperture used for the previous exposure control; and the focus adjustment of the imaging optical system An aperture value setting unit that sets the aperture value of the aperture in the next exposure control based on the minimum value of the effective range of the aperture value of the aperture, and the aperture value setting unit has a minimum value of the effective range. the exposure calculation by seeking said diaphragm Rino aperture value and said diaphragm aperture value used for exposure control of the last in the case of excess, respectively, and the diaphragm Rino aperture in the next exposure control , To set the diaphragm aperture value used for exposure control of the last time.

In addition, the aperture value setting unit is obtained by the exposure calculation when an absolute value of a difference between the luminance value used in the previous exposure control and the luminance value obtained by the photometry calculation unit is less than a threshold value. diaphragm Rino aperture, based on the grain Rino aperture value and the effective range used in the exposure control of the last, to set the diaphragm Rino aperture in the next exposure control.

In addition, the aperture value setting unit , when the absolute value of the difference between the luminance value used in the previous exposure control and the luminance value obtained by the photometric calculation unit exceeds a threshold value, in the next exposure control as grain Rino aperture, to set the diaphragm Rino aperture value determined by the exposure calculation.

Further, the aperture control device of the present invention includes an aperture that adjusts the amount of incident subject light, a photometric calculation unit that repeatedly calculates a luminance value based on the subject light whose amount of light has been adjusted by the aperture, and the repeatedly calculated An exposure calculation unit for performing an exposure calculation using a luminance value; the aperture value of the aperture obtained by the exposure calculation; the aperture value of the aperture used for the previous exposure control; and the focus adjustment of the imaging optical system An aperture value setting unit for setting the aperture value of the aperture in the next exposure control based on the minimum value of the effective range of the aperture value of the aperture, and the aperture value setting unit is obtained by the exposure calculation when the diaphragm Rino aperture is equal to or less than the diaphragm Rino aperture used for exposure control of the last as the diaphragm Rino aperture in the next exposure control, the grain was determined by the exposure calculation To set the aperture value.

The imaging apparatus of the present invention, a diaphragm control device described above, an imaging device that outputs an image signal obtained by more amount of light Ri said aperture to receive the object light that has been adjusted for each of the predetermined intervals, wherein the photometric calculation section you calculate the luminance value based on the image signal outputted for each predetermined distance from the imaging device.

In this case, the exposure calculating section, that perform exposure calculation using the iris aperture value set by said luminance values calculated by the photometric calculation unit and the aperture value setting unit again.

Further, the exposure control unit that controls exposure based on the exposure calculation unit by the exposure calculation executed again result, further wherein the imaging device, you output an image signal based on the exposure control by the exposure control unit .

  According to the present invention, it is possible to prevent a decrease in accuracy in focus adjustment of an imaging optical system.

It is a figure which shows the structure of the imaging device using the aperture_diaphragm | restriction control apparatus of this invention. It is a flowchart which shows the flow of exposure control in a live view display. (A) When the aperture value Av1 calculated by the exposure calculation is smaller than the aperture value Av used for exposure control, (B) the minimum value Av _min of the settable range of the aperture value is changed from the aperture value Av to the aperture value Av1. (C) is a diagram showing a case where the minimum value Av _min of the settable range of the aperture value exceeds the aperture value Av and the aperture value Av1, respectively.

  FIG. 1 shows an outline of a digital camera as an example of a photographing apparatus of the present embodiment. The digital camera 10 includes a lens unit 11 and a camera body 12 to which the lens unit 11 can be attached and detached. The lens unit 11 and the camera body 12 are provided with a pair of mounts 13 and 14 that form a male-female relationship, respectively. When the lens unit 11 is attached to the camera body 12, the mount 13 provided on the lens unit 11 is coupled to the mount 14 of the camera body 12 by a bayonet mechanism or the like. Each of the mounts 13 and 14 is provided with an electrical contact. When the lens unit 11 is attached to the camera body 12, the electrical contacts provided on the mounts 13 and 14 come into contact with each other, and the electrical connection between them is established.

  Next, the configuration of the lens unit 11 will be described. The lens unit 11 includes an imaging optical system 21, a lens driving mechanism 22, a diaphragm 23, a diaphragm driving mechanism 24, a lens driving control circuit 25, and the like. The lens driving mechanism 22 and the aperture driving mechanism 24 are connected to the lens driving control circuit 25, respectively.

  The imaging optical system 21 includes a plurality of lenses such as a zoom lens and a focus lens. The lenses constituting the imaging optical system 21 can be moved in the optical axis (L) direction by the lens driving mechanism 22. The position of each lens of the imaging optical system 21 is detected by an encoder (not shown). A detection signal indicating the detected position of each lens is output to the lens drive control circuit 25. The lens drive control circuit 25 receives the input detection signal and calculates a shooting distance and a focal length at the time of shooting. These calculated values are output to the camera body 12. Further, the lens drive control circuit 25 calculates a settable range of the aperture value in the focus adjustment of the imaging optical system 21 based on the lens information of each lens constituting the imaging optical system 21. The aperture value settable range is a range from the minimum value to the maximum value of the aperture value that guarantees the accuracy of focus adjustment. Then, the lens drive control circuit 25 outputs information on the minimum value in the settable range of the calculated aperture value to the camera body 12. The lens drive control circuit 25 outputs information on the minimum value of the aperture value settable range to the camera body 12. However, the present invention is not limited to this. It may be output to the body 12.

  The diaphragm 23 adjusts the amount of light incident on the camera body 12 by opening and closing the diaphragm blades. The diaphragm drive mechanism 24 controls the opening degree (opening diameter) of the diaphragm 23. The lens drive control circuit 25 communicates with the camera body 12 through the electrical contacts of the mounts 13 and 14 and executes various controls in the lens unit 11. In addition, the lens drive control circuit 25 transmits lens data and the like recorded in a ROM (not shown) to the camera body 12.

  1 illustrates an example of a so-called single-lens reflex digital camera 10 in which the lens unit 11 is detachably attached to the camera body 12. However, the present invention is not limited to this, and the lens unit 11 is not limited to the camera body 12. It may be a so-called compact type digital camera fixed to the camera.

  In FIG. 1, the quick return mirror, the sub mirror, the finder optical system, and the like are not mentioned, but a single-lens reflex digital camera having these configurations may be used, or these configurations may be omitted. .

  Next, the configuration of the camera body 12 will be described. The camera body 12 includes an image sensor 31, a mechanical shutter 32, a shutter drive mechanism 33, an image processing circuit 34, a display control circuit 35, a display device 36, a compression / decompression circuit 37, an image storage unit 38, a body drive control circuit 39, and an operation member. 40 etc.

  The image pickup device 31 is constituted by a CCD image sensor or a CMOS image sensor, for example. The subject light incident on the camera body 12 via the lens unit 11 described above passes through the mechanical shutter 32 and enters the image sensor 31. The image sensor 31 converts subject light into electric charges (photoelectric conversion), and accumulates the converted electric charges. The accumulated charge is output from the image sensor 31 to the image processing circuit 34 as an image signal. The image signal output from the image sensor 31 is converted into a digital image signal by an A / D converter (not shown) and then input to the image processing circuit 34. When performing live view display, the image sensor 31 outputs an image signal (through image signal) that is a source of a through image at a predetermined frame rate such as 30 fps.

  The mechanical shutter 32 blocks subject light that is incident upon the closing operation, and causes the subject light to be incident on the image sensor 31 during the opening operation. The shutter drive mechanism 40 performs an opening / closing operation of the mechanical shutter 32.

  When performing live view display, the image processing circuit 34 calculates an AE evaluation value based on the input through image signal. Further, the image processing circuit 34 executes image processing for displaying the input through image signal on the display device 36. The image processing circuit 34 performs image processing for displaying on the display device 36 and image processing for storing as image data on the image signal (main image signal) input during the imaging processing.

  The image processing circuit 34 performs resolution (pixel number) conversion processing on the image signal to be displayed on the display device 36. After this resolution conversion processing, the image processing circuit 34 outputs the processed image signal to the display control circuit 35. The display control circuit 35 displays an image based on the input image signal on the display device 36.

  The compression / decompression circuit 37 performs compression processing on the input image signal. The compressed image signals (hereinafter referred to as encoded data) are collected into one image file together with information such as exposure conditions at the time of shooting and stored in the image storage unit 38. In addition, when displaying an image based on the image file stored in the image storage unit 38, decompression processing is performed on the encoded data of the image file.

  Here, the image storage unit 38 may be a nonvolatile memory or a hard disk drive built in the camera body 12, or may be a memory card, a magnetic disk, or an optical disk that can be attached to and detached from the camera body 12. Good.

  The body drive control circuit 39 includes a microcomputer, a ROM, a RAM, and the like (not shown). The body drive control circuit 39 executes drive control of the image sensor 31, shutter drive mechanism 33, image processing circuit 34, display control circuit 35, compression / decompression circuit 37, image storage unit 38, and the like. The body drive control circuit 39 has functions such as a photometry calculation unit 45, an exposure calculation unit 46, and an exposure control unit 47. The photometric calculation unit 45 obtains a luminance value using the AE evaluation value calculated by the image processing circuit 34. Further, the exposure calculation unit 46 performs live view display and exposure calculation during imaging. The exposure control unit 47 performs exposure control based on the result of the exposure calculation in the exposure calculation unit 46.

  Next, the flow of exposure control processing during live view display will be described based on the flowchart of FIG. Although illustration is omitted, when the main power supply of the digital camera 10 is turned on, an initialization operation that is not described is executed. After this initialization operation is executed, when the setting in the digital camera 10 is the shooting mode, live view display is started on the display device 36. Hereinafter, the brightness value and aperture value used in the previous exposure control are referred to as Bv and Av, and the brightness value and aperture value calculated by the exposure calculation are referred to as Bv1 and Av1. These values are values converted to APEX.

  Step S101 is processing for calculating the luminance value Bv1. When exposure control by the body drive control circuit 39 is executed, a through image signal is output from the image sensor 31 to the image processing circuit 34. The image processing circuit 34 calculates an AE evaluation value using the input through image signal. The image processing circuit 34 outputs the calculated AE evaluation value to the body drive control circuit 39. The body drive control circuit 39 calculates the luminance value Bv1 using the input AE evaluation value.

  Step S102 is a process for performing an exposure calculation. The body drive control circuit 39 performs exposure calculation using the luminance value Bv1 obtained in step S101 and the program diagram (EV diagram) for live view display. Thereby, the aperture value Av1 is calculated.

Step S103 is processing for determining whether or not the calculated aperture value Av1 exceeds the aperture value Av used for the previous exposure control. The body drive control circuit 39 determines whether or not the following expression (1) is satisfied.
Aperture value Av1> Aperture value Av (1)
The body drive control circuit 39 sets the determination process in step S103 to Yes when the expression (1) is satisfied. In this case, the process proceeds to step S104. On the other hand, if the body drive control circuit 39 does not satisfy the expression (1), the determination process in step S103 is No. In this case, the process proceeds to step S109.

  In step S103, it is determined whether or not the aperture value Av1 exceeds the aperture value Av. However, the present invention is not limited to this, and it is determined whether or not the aperture value Av1 is greater than or equal to the aperture value Av. You may judge.

Step S104 is processing for determining whether or not the absolute value of the difference between the luminance value Bv used for the previous exposure control and the calculated luminance value Bv1 is less than a threshold value. The body drive control circuit 39 determines whether or not the following expression (2) is satisfied.
| Luminance value Bv−Luminance value Bv1 | <0.5 (2)
The body drive control circuit 39 sets the determination processing in step S104 to Yes when the expression (2) is satisfied. In this case, the process proceeds to step S105. On the other hand, if the body drive control circuit 39 does not satisfy the expression (2), the determination process in step S104 is No. In this case, the process proceeds to step S109.

  In the above-described equation (2), the brightness value 0.5 is cited as the threshold value. However, it is only necessary to determine whether or not the fluctuation of the brightness value is minute, so the brightness value 0.5 is used as the threshold value. There is no need. Further, in step S104, it is determined whether or not the absolute value of the difference between the luminance value Bv used for the previous exposure control and the calculated luminance value Bv1 is less than the threshold value. It is not necessary, and it may be determined whether or not the absolute value of the difference between the luminance value Bv used for the previous exposure control and the calculated luminance value Bv1 is equal to or less than a threshold value.

Step S105 is processing for calculating a settable range of the aperture value. The body drive control circuit 39 instructs the lens drive control circuit 25 to calculate the aperture value settable range. In response to this, the lens drive control circuit 25 calculates the settable range of the aperture value based on the lens information of each lens constituting the imaging optical system 21. After calculating the aperture value settable range, the lens drive control circuit 25 outputs information on the minimum value Av _min in the calculated aperture value settable range to the body drive control circuit 39.

In step S106, the aperture value Av1 calculated by the exposure calculation is not less than the minimum value Av _min in the aperture value setting range, and the aperture value Av used in the previous exposure control is the aperture value setting range. it is determined whether it is less than the minimum value Av _min at. The body drive control circuit 39 determines whether or not the following expressions (3) and (4) are satisfied.

Aperture value Av1 ≧ minimum value Av _min within a settable range of aperture value (3)
Aperture value Av <minimum value Av _min within the settable range of aperture value (4)
The body drive control circuit 39 determines Yes in step S106 when the expressions (3) and (4) are satisfied. In this case, the process proceeds to step S107. On the other hand, if the body drive control circuit 39 does not satisfy either of the expressions (3) and (4), or does not satisfy both the expressions (3) and (4), the determination in step S106 is No. And In this case, the process proceeds to step S108.

  In step S106, it is determined whether or not both the expressions (3) and (4) are satisfied. However, the present invention is not limited to this, and the following expression (5) is satisfied. It may be determined whether or not.

Aperture value Av <minimum value Av _min within a settable range of aperture value ≦ aperture value Av1 (5)
In step S106, the aperture value Av1 calculated by the exposure calculation is equal to or larger than the minimum value Av _min in the aperture value setting range, and the aperture value Av used in the previous exposure control is the aperture value setting. Although it is determined whether or not it is less than the minimum value Av _min in the possible range, the present invention is not limited to this, and the aperture value Av1 calculated by the exposure calculation is the minimum value in the aperture value settable range. It may be determined whether or not the aperture value Av that exceeds Av _min and is used in the previous exposure control is equal to or less than the minimum value Av _min in the aperture value setting range. Furthermore, In addition, the aperture value Av1 calculated by the exposure calculation, the minimum value Av _min or more at the settable range of the aperture value, and the aperture value Av, which is used in the previous exposure control, setting the aperture It is determined whether or not the minimum value Av _{min is} within the possible range, or the aperture value Av1 calculated by the exposure calculation exceeds the minimum value Av _min in the aperture value settable range, and the previous exposure control It may be determined whether or not the aperture value Av used in step 1 is less than the minimum value Av _min in the aperture value settable range.

Step S107 is a process of setting the newly set aperture value Av to the minimum value Av _min in the aperture value settable range. The process of step S107 is executed when the determination process of step S106 is Yes.

Step S108 is a process of setting the newly set aperture value Av to the minimum value Av _min in the aperture value settable range. The process of step S108 is executed when the determination process of step S106 is No.

  Step S109 is processing to set the newly set aperture value Av to the calculated aperture value Av1. The process of step S109 is executed when the determination process of step S103 is No or when the determination process of step S104 is No.

  Step S110 is processing for performing exposure control. The body drive control circuit 39 sets the brightness value Bv1 calculated in step S101 as the brightness value Bv in the next exposure control. Then, the body drive control circuit 39 performs exposure calculation again using the set brightness value Bv and aperture value Av. Thereby, the exposure time (shutter speed) Tv and the photographing sensitivity Sv are calculated. After this exposure calculation, the body drive control circuit 39 executes exposure control using the obtained value. Thereby, a through image signal based on the newly obtained exposure condition is acquired. The image processing circuit 34 performs image processing for displaying the obtained through image signal on the display device 36 and outputs the processed image to the display control circuit 35. In response to this, the display control circuit 35 displays a through image on the display device 36.

  Step S111 is processing to determine whether or not to end the live view display. An operation signal based on the operation of the operation member 40 is input to the body drive control circuit 39. When an operation signal based on the operation of the operation member 40 is input to the body drive control circuit 39, the body drive control circuit 39 determines whether or not the input operation signal is an operation signal indicating the end of the live view display. Determine. If the body drive control circuit 39 determines that the input operation signal is an operation signal indicating the end of the live view display, the determination process of step S111 is set to Yes. In this case, the body drive control circuit 39 outputs a signal for stopping the live view display to the display control circuit 35. Upon receiving this signal, the display control circuit 35 stops the live view display on the display device 36. That is, the process of the flowchart of FIG.

  On the other hand, if the body drive control circuit 39 determines that the input operation signal is not an operation signal indicating the end of the live view display, the determination process in step S111 is No. In this case, the process returns to step S101, and the live view display is continuously executed. When the operation member 40 is not operated, the operation signal based on the operation of the operation member 40 is not input to the body drive control circuit 39. In this case, the body drive control circuit 39 also performs step S111. This determination process is No. Also in this case, the process returns to step S101, and the live view display is continuously executed.

  As shown in FIG. 3A, when the aperture value Av1 calculated by the exposure calculation is equal to or smaller than the aperture value Av set in the previous exposure control, the aperture 23 is driven so as to open the aperture diameter. . In this case, the newly calculated aperture value Av1 is set as the aperture value Av in the new exposure control.

  When the newly calculated aperture value Av1 exceeds the aperture value Av set in the previous exposure control, the aperture 23 is driven and controlled to reduce the aperture diameter. In this case, the absolute value of the difference between the luminance value Bv used in the previous exposure calculation and the luminance value Bv1 calculated in the exposure calculation is calculated. If the difference between the luminance value Bv used in the previous exposure control and the luminance value Bv1 calculated in the exposure calculation is equal to or greater than the threshold value, that is, if the fluctuation of the luminance value is large, the aperture value calculated by the exposure calculation Av1 is set as the aperture value Av in the next exposure control.

  When the difference between the brightness value Bv used in the previous exposure control and the brightness value Bv1 calculated in the exposure calculation is less than the threshold value, that is, when the fluctuation of the brightness value is small, it is used in the next exposure control. In setting the aperture value Av to be set, in addition to Av1 calculated by the exposure calculation and the aperture value Av used for the previous exposure control, the aperture value calculated from the lens information of each lens of the imaging optical system 21 is set. The possible range is taken into account.

As shown in FIG. 3B, in the relative relationship between the aperture value Av used in the previous exposure control, the aperture value Av1 calculated in the exposure calculation, and the minimum value Av _min of the settable range of the aperture value , minimum value _{Av min} settable range of aperture value is less than the aperture value Av1, and, when the minimum value _{Av min} settable range of the aperture value is equal to or greater than the aperture value Av is the settable range of the aperture value The minimum value Av _min is set as the aperture value Av in the next exposure control.

On the other hand, as shown in FIG. 3C, in relation to the aperture value Av set by the previous exposure control, the aperture value Av1 calculated by the exposure calculation, and the minimum value Av _min of the aperture value settable range. When the minimum value Av _min of the settable range of the aperture value exceeds both the aperture value Av and the aperture value Av1, the aperture value Av set in the previous exposure control is the aperture value in the next exposure control. It is set again as Av.

That is, when the luminance change between the preceding and following exposure controls is small, the minimum value Av _min of the settable range of the aperture value is from the aperture value Av used in the previous exposure control to the aperture value Av1 calculated by the exposure calculation. Is set as the aperture value Av in the next exposure control, and otherwise, the aperture value Av used in the previous exposure control is continuously used in the next exposure control. The aperture value is set. Here, the settable range of the aperture value is a range calculated from lens information of each lens of the imaging optical system 21, in other words, an aperture value range suitable for focus adjustment of the imaging optical system 21. That is, when the minimum value Av _min of the settable range of the aperture value is set as the aperture value in the next exposure control, the aperture value takes into account the focus adjustment in the imaging optical system 21. Thereby, it is possible to prevent a decrease in accuracy in focus adjustment of the imaging optical system 21.

  On the other hand, in other cases, since the aperture value Av used in the previous exposure control is continuously used, it is not necessary to frequently change the aperture diameter in the aperture. As a result, it is possible to suppress the occurrence of brightness hunting in live view display. In addition, the generation of operation noise when the aperture diameter of the diaphragm is frequently changed is reduced. Thereby, a user's discomfort with respect to an operation sound can be reduced, and the power consumption in the digital camera 10 can be suppressed.

  In the present embodiment, the case where the luminance value is calculated based on the image signal output from the image sensor is described. However, the present invention is not limited to this, and a photometric sensor is provided in the digital camera. It is also possible to calculate the luminance value using the output signal.

  In the present embodiment, a digital camera as an example of a photographing apparatus is taken as an example. However, the present invention is not limited to this, and includes a portable terminal such as a cellular phone having a camera function, a camera, and a PC. The present invention can be used in a camera system.

  In addition to this, the function of the lens drive control circuit and the body drive control circuit shown in FIG. 1 and the aperture control device capable of executing the processing of the flowchart of FIG. 2 may be used.

  Further, it may be a diaphragm control program capable of causing a computer to execute the functions of the lens drive control circuit and the body drive control circuit shown in FIG. 1 and the processing of the flowchart of FIG. The aperture control program is preferably stored in a computer-readable storage medium such as a memory card, an optical disk, or a magnetic disk.

  DESCRIPTION OF SYMBOLS 10 ... Digital camera, 11 ... Lens unit, 12 ... Camera body, 21 ... Imaging optical system, 23 ... Aperture, 25 ... Lens drive control circuit, 31 ... Imaging element, 32 ... Mechanical shutter, 34 ... Image processing circuit, 35 ... Display control circuit 36 ... Display device 39 ... Body drive control circuit 45 ... Metering calculation unit 46 ... Exposure calculation unit 47 ... Exposure control unit

Claims (8)

Litho aperture for adjusting the light quantity of the subject light incident,
A photometric calculation unit that calculates repeatedly the luminance value based on the subject light more quantity is adjusted to Ri said aperture,
An exposure calculation unit that performs an exposure calculation using the luminance value repeatedly calculated;
The diaphragm Rino aperture determined by the exposure calculation, based the diaphragm Rino aperture value used for the previous exposure control, and the minimum value of the effective range of the diaphragm Rino aperture in the focus adjustment of the imaging optical system Te, aperture value setting unit that sets the diaphragm Rino aperture in the next exposure control,
Equipped with a,
The aperture value setting unit, when the minimum value of the effective range is less than the aperture value of the aperture obtained by the exposure calculation, and is equal to or greater than the aperture value of the aperture used for the previous exposure control, An aperture control device that sets a minimum value of the effective range as the aperture value of the aperture in the next exposure control . An aperture that adjusts the amount of incident subject light;
A photometric calculation unit that repeatedly calculates a luminance value based on the subject light whose light amount is adjusted by the diaphragm;
An exposure calculation unit that performs an exposure calculation using the luminance value repeatedly calculated;
Next time based on the aperture value of the aperture obtained by the exposure calculation, the aperture value of the aperture used for the previous exposure control, and the minimum value of the effective range of the aperture value of the aperture in the focus adjustment of the imaging optical system. An aperture value setting unit for setting the aperture value of the aperture in the exposure control of
With
The aperture setting unit, when the minimum value of the effective range, respectively excess obtained the grain Rino aperture value and said diaphragm aperture value used for exposure control of the last by the exposure calculation, the as the diaphragm Rino aperture in the next exposure control, the diaphragm aperture Ri controller to set the aperture value used for exposure control of the last time. In the iris control device according to claim 1 or 2 ,
The aperture value setting unit , when the absolute value of the difference between the luminance value used for the previous exposure control and the luminance value obtained by the photometric calculation unit is less than a threshold value, aperture, on the basis of the aperture value and the effective range of the aperture used for exposure control of the previous, the next time the diaphragm Rino diaphragm Ri controller to set the aperture value in the exposure control. In the iris control device according to claim 1 or 2 ,
The aperture value setting unit , when the absolute value of the difference between the luminance value used in the previous exposure control and the luminance value obtained by the photometric calculation unit exceeds a threshold value , the aperture value in the next exposure control as the aperture value, Ri aperture to set the aperture of the aperture value determined by said exposure calculating controller. An aperture that adjusts the amount of incident subject light;
A photometric calculation unit that repeatedly calculates a luminance value based on the subject light whose light amount is adjusted by the diaphragm;
An exposure calculation unit that performs an exposure calculation using the luminance value repeatedly calculated;
Next time based on the aperture value of the aperture obtained by the exposure calculation, the aperture value of the aperture used for the previous exposure control, and the minimum value of the effective range of the aperture value of the aperture in the focus adjustment of the imaging optical system. An aperture value setting unit for setting the aperture value of the aperture in the exposure control of
With
The aperture setting unit, when the exposure calculation by the diaphragm determined aperture value is equal to or less than the aperture value of the aperture used for exposure control of the previous, wherein the diaphragm Rino diaphragm in the next exposure control value as the exposure calculation by the aperture diaphragm Ri controller to set the aperture value determined. A diaphragm control device according to any one of claims 1 to 5 ,
An image sensor that outputs an image signal obtained by receiving the subject light, the light amount of which is adjusted by the diaphragm, at each predetermined interval;
With
The said photometry calculating part is an imaging device which calculates the said luminance value based on the image signal output for every said predetermined interval from the said image pick-up element. The imaging device according to claim 6 ,
The exposure apparatus, wherein the exposure calculation unit again performs an exposure calculation using the brightness value calculated by the photometry calculation unit and the aperture value of the aperture set by the aperture value setting unit . The imaging apparatus according to claim 7,
An exposure control unit that performs exposure control based on a result of exposure calculation executed again by the exposure calculation unit;
The image pickup device outputs an image signal based on exposure control by the exposure control unit.

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