JP3496792B2 - Aperture control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture control device applicable to, for example, an electronic still camera.

[0002]

2. Description of the Related Art An electronic still camera has been put into practical use, in which an image of an object to be photographed is encoded and combined to record / reproduce on / from a recording medium such as a memory card. FIG. 5 shows an example of a conventional electronic still camera. In FIG. 5, a diaphragm 52 is provided behind the imaging lens 51. Aperture 5
2 is circular and has a hole 52a at the center. A CCD 53, which is an image sensor, is provided behind the diaphragm 52,
The CCD 53 has an image pickup lens 51 and a hole 52 of a diaphragm 52.
The image of the subject is input through a.
The CCD 53 includes a CDS 54 which is a camera control unit.
Are connected. These imaging lens 51, diaphragm 52,
The CCD 53, the CDS 54, and the like constitute the image pickup unit 70 of the camera.

The CDS 54 is connected to an A / D conversion circuit 55 provided outside the image pickup section 70 of the camera. A /
The D conversion circuit 55 includes a digital signal processing circuit 56, and the digital signal processing circuit 56 includes an image data compression / expansion circuit 5.
7, the image data compression / expansion circuit 57 has a FIFO (first in / first out) circuit 58
A memory card 60 is connected to the O circuit 58 via a memory card I / F. The memory card I / F 59 and the memory card 60 are connected by an address bus / data bus 71. The address bus / data bus 71 is branched in the middle of the SRAM.
It is connected with 61. Although the signal is only output from the A / D conversion circuit 55 to the digital signal processing circuit 56, the digital signal processing circuit 56 and the image data compression / expansion circuit 57 exchange signals with each other. You can do it. Further, signals can be exchanged between the image data compression / expansion circuit 57 and the FIFO circuit 58, and between the FIFO circuit 58 and the memory card I / F 59. In addition, the memory card I / F 59, SRAM 61, memory card 60,
Signals can be exchanged with each other by an intervening address bus / data bus 71.

The digital signal processing circuit 56, the image data compression / expansion circuit 57, and the memory card I / F 59 are connected to the CPU 62, which is a central processing unit, and the digital signal processing circuit 56, the image data compression / expansion circuit 57, and the memory. A signal can be output from each part of the card I / F 59 to the CPU 62, and conversely, a signal can be output from the CPU 62 to each member of the digital signal processing circuit 56, the image data compression / expansion circuit 57, and the memory card I / F 59. It is like this.

An SG65 which is a timing signal generating section is connected to the CPU 62, and the SG65 is further connected to the CCD 56 and the CDS 54 in the image pickup section 70 of the camera. A driver 66 connected to the diaphragm 52, which is a mechanical member of the image pickup unit 70 of the camera, is connected to the CPU 62. Further, the CPU 62 has a strobe 67.
Are connected.

Further, the CPU 63 is connected to a mode display section 63 made of liquid crystal or the like for monitoring the status of the camera and the like, and an operation section 64 for performing shooting and various settings of the camera.

When an image of a subject is picked up by the electronic still camera having the above-mentioned structure, the picked-up image is formed on the image pickup surface of the CCD 53 through the image pickup lens 51 and the diaphragm 52, and an image signal is output from the CCD 53. To be done. CCD
The image signal from 53 is a CDS as an analog image signal.
It is input to the A / D conversion circuit 55 via 54 and converted into a digital image signal. The digital image signal is input to the digital signal processing circuit 56, subjected to digital processing, and then input to the image data compression / expansion circuit 57. The image data compression / expansion circuit 57 encodes the digital image signal, and the capacity is compressed by this encoding. The encoded digital image signal is sent to the FIFO circuit 58 and recorded by being DMA-transferred to the memory card 60 by a DMA (direct memory access) controller incorporated in the CPU. When reproducing the digital image signal recorded in the memory card 60, image data transfer in the opposite direction (memory card 60 → memory card I / F 59 → FIFO circuit 58 → image data compression / expansion circuit 57 → Digital signal processing 56)
Is being done.

Next, the image pickup section 70 of the electronic still camera will be described. A diaphragm 52 is arranged in front of the CCD 53 of the image pickup unit 70, that is, on the side of a subject (not shown). Since the diaphragm 52 is connected to the driver 66, it is driven by the driver 66 and is arranged so as to advance to the front of the CCD 53 and overlap with it, or the CCD 53.
Is operated to exit from a position in front of. The command for the operation of the diaphragm 52 is sent from the CPU 62 to the driver 66 connected to the diaphragm 52.

Normally, the diaphragm 52 is advanced from the position in front of the CCD 53 and is in an open state. In the example of the Ev diagram shown in FIG. 6, the brightness is Lv (light value) 5 to Lv1.
This is the case of the range of 2. When the brightness exceeds Lv12, C
A command is transferred from the PU 62 to the driver 66, and the diaphragm 52 is driven by the driver 66 to arrange the diaphragm 52 having the diaphragm value F8 in front of the CCD 53. Note that FIG.
In the example, the open aperture value is F2, and at the open aperture value F2, the shutter speed can be varied within the range of 1/8 second to 1/1000 second. Also, the aperture value is F8
In the case of, the shutter speed exceeds 1/60 second and 1
It can be changed within a range of / 2000 seconds or less. By controlling the diaphragm 52 according to the brightness in this way, a proper image can be obtained without making the image of the subject too bright or too dark.

A technique related to the image pickup section of the camera as described above is disclosed in Japanese Patent Application Laid-Open No. 02-186884 and Japanese Patent Application Laid-Open No. 0-186884.
It is described in JP-A-2-257126, JP-A-02-072081 and JP-A-03-024871.

The image pickup apparatus and the interchangeable lens system disclosed in Japanese Patent Laid-Open No. 02-186884 change the amount of feedback according to the degree of change in the output of the image pickup element when the exposure state is feedback controlled.
It is designed to prevent hunting for exposure control.

The image pickup apparatus described in Japanese Patent Application Laid-Open No. 02-257126 has a control means for substantially optimizing the response speed of each displacement operation in which the lens diaphragm member of the optical system is displaced,
By providing the displacement driving means for the diaphragm member, the iris control with the optimum response speed can be performed in any changing direction of the diaphragm.

In the video camera described in Japanese Patent Laid-Open No. 02-072081, the shutter speed change in the automatic exposure mode is performed stepwise by two shutter speed determining means in accordance with the change in subject brightness. The image can be prevented from being disturbed by the stable control of the diaphragm.

The image pickup apparatus disclosed in Japanese Patent Laid-Open No. 03-024871 does not fade the image in the electronic viewfinder when the fade is made to function, and always checks the output image of the image pickup element to check the operation state of the fade. By displaying this, it is possible to take pictures that make full use of the fade function.

The electronic still camera has a monitor device for displaying an image of a photographed subject in real time. With this monitor device, it is possible to shoot while confirming the image of the subject input to the electronic still camera.

[0016]

In the electronic still camera described above, the image of the subject is picked up by the CCD 53 and displayed on the monitor device as long as the power is turned on even in the case other than the photographing, and the brightness is reduced. The aperture 52 is controlled in accordance with the above. Therefore, when the electronic still camera is used near the aperture change, that is, near the boundary between the aperture values F2 and F8 in the Ev diagram of FIG. 6, the aperture 52 is advanced to the front of the CCD 53 or the aperture 52 The operation of advancing from the front of the CCD 53 frequently occurs to cause hunting, and this hunting increases power consumption. In particular, since an electronic still camera has a small battery capacity, an increase in power consumption adversely affects shooting time and the like.

Further, the driving of the diaphragm 52, the power supply fluctuation, and the electrical noise accompanying the change of the diaphragm have a bad influence such as disturbance on the image displayed on the monitor device. Further, since the diaphragm 52 crosses in front of the CCD 53 due to the change of the diaphragm value, the image of the diaphragm 52 is input to the CCD 53, which is displayed on the monitor device and causes the disorder of the monitor image.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and suppresses frequent hunting in the vicinity of changing the aperture to suppress power consumption, and
An object of the present invention is to provide an aperture control device that eliminates the disturbance of the image displayed on the monitor device.

[0019]

The invention according to claim 1 is
Depending on the brightness of the subject, it may move on or off the optical axis.
Conversion obtain throttle device off the aperture by retracting, the image pickup device an image of the object is input through the lens, by the throttle control apparatus of an image pickup apparatus having a monitor image of the subject being imaged is displayed on the image sensor Therefore, during the monitor display, the shutter and aperture device are controlled by the EV diagram with hysteresis for aperture switching, and while the image of the subject is being displayed in real time, metering is performed to calculate the aperture value in advance. When the number of out-of-shutter movements at the set aperture value increases, the aperture device advances on the optical axis or retracts outside the optical axis to change the preset aperture value.

According to the second aspect of the invention, the screen is displayed while the monitor is displayed.
When the display is switched, the monitor screen is turned off .

[0021] The invention of claim 3, wherein, when is switched aperture in the monitor display, wherein the monitor screen is held.

The invention according to claim 4 is characterized in that the monitor screen is faded when the aperture is switched during the monitor display.

[0023]

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an aperture control device according to the present invention will be described below with reference to the drawings.
First, the configuration of an electronic still camera in which the aperture control device is used will be described. In FIG. 1, a CCD 1 serving as a camera control unit is connected to a CCD 1 serving as an image pickup device on which an image of a subject is formed. The CDS2 has a 10-bit unit provided outside the image pickup unit of the electronic still camera.
Analog-to-digital converter (hereinafter referred to as "A / D") 3
Are connected. In this 10-bit A / D3,
The image data of the subject input from the CCD 1 via the CDS 2 is digitized. 1
An image processing circuit IPPV4 is connected to the 0-bit A / D3, and various image processes are performed on the image data digitized by the IPPV4.

Two D-RAMs 6, 6'which are frame memories are connected to the IPPV 4. Further, the IPPV4 has a CDS2, a compression / expansion circuit 5, and a C
Driver 7, monitor device 10, CP connected to CD1
U9 are respectively connected. A memory card 11 is connected to the compression / expansion circuit 5 so that captured image data can be encoded and compressed to be recorded in the memory card 11. Conversely, memory card 1
The image data recorded in No. 1 is expanded by the compression / expansion circuit 5 to be restored to the original image data. Further, the CPU 9 has a plunger driver 8
And CDS2 are connected.

The CPU 9 performs photometry based on the brightness data from the IPPV 4, sets a shutter speed in the IPPV 4, sets whether or not the monitor signal is output to the IPPV 4, and changes the F value according to the photometric value. It is possible to control the plunger driver by judging whether or not.

Of the components that make up the electronic still camera as described above, the image pickup section of the electronic still camera is made up of components such as CCD 1 and CDS 2. The image pickup unit of such an electronic still camera has a configuration as shown in FIG. In FIG. 2, a taking lens 20 is attached in front of the CCD 1, that is, on the subject side. A diaphragm 21 is provided in front of the taking lens 20. The diaphragm 21 is circular and has a hole 21a formed in the center. An image of a subject is formed on the CCD 1 through the photographing lens 20 through the hole 21a of the diaphragm 21 and the photographing lens 20, or without passing through the diaphragm 21.

The circular diaphragm 21 is attached to a lever 25 having a bell crank shape . The lever 25 is provided with arm portions 25a and 25b on both sides centering on a central shaft hole, and a diaphragm 21 is provided at one end of the arm portion 25b. The shaft hole of the lever 25 is passed through the shaft of a fixing member (not shown). Therefore, the lever 25 can be rotated clockwise or counterclockwise around the shaft hole. Lever 25 when the restrictor 25 when rotated by the urging force of the spring 30 advances on the optical axis of the lens 20, and rotated in the clockwise direction the lever 25 against the urging force of the spring 30,
The diaphragm 21 is adapted to be retracted from the optical axis of the lens 20 as shown by the dotted line.

A lever 24 is provided on the upper rear side of the lever 25 so as to be orthogonal to the lever 25. The lever 24 is a bell crank-shaped member, and is provided with a substantially circular bearing portion 24a at the center thereof. A shaft hole is provided in the center of the bearing 24a, and the shaft hole is inserted through the shaft of a fixing member (not shown). Therefore, the lever 24 can rotate clockwise or counterclockwise around the shaft hole. Arms 24b and 24c are provided on both sides of the bearing 24a. Of these, one end of the arm portion 24c is bent upward to provide a bent portion 24e. One end portion of the arm portion 24c enters below one end portion of the arm portion 25a of the lever 25, and moreover, the arm portion 25 of the lever 25 is bent by the bent portion 24e.
It has a form hooked on one end of a.

One end of the arm portion 24b of the lever 24 is connected to the shaft 23 of the bistable plunger 22. Axis 23
By energizing the bistable plunger 22 in the forward and reverse directions, the bistable plunger 22 can be projected toward the front side or retracted to return to the position before the projection, and each position can be maintained. There is. Since one end of the arm portion 24b of the lever 24 is connected to the shaft 23 of the bistable plunger 22 as described above, the lever 24 is also rotated with the operation of the shaft 23.

The plunger driver 8 shown in FIG. 1 is connected to the bistable plunger 22, and when the CPU 9 transfers an instruction to the plunger driver 8, the bistable plunger 22 is activated and the axis is rotated. 23
Can be projected or the shaft 23 can be retracted. It should be noted that when the CPU 9 transmits a shaft projecting command to the plunger driver 8 and the shaft 23 is once projected from the bistable plunger 22, C
The shaft 23 is held in that position until the protrusion release command (command for retracting the shaft) is transmitted from the PU 9 to the plunger driver 8, and the protruding state is maintained. Further, when the protrusion release command is transferred from the CPU 9 to the plunger driver 8 and the shaft 23 is retracted, the CPU
The shaft 23 is held in that position and kept in the retracted state until a shaft projecting command is transmitted from 9 to the plunger driver 8.

When the shaft 23 of the bistable plunger 22 projects, the lever 24 rotates counterclockwise around the shaft hole of the bearing 24a, and its arm portion 24c descends, so that the lever 25 is urged by the spring 30. It rotates counterclockwise, and the diaphragm 21 provided at the end of the arm 25b of the lever 25
The lens 20 moves on the optical axis A. In this way, the arm 2
When the diaphragm 21 provided at the end of 5b advances on the optical axis A, the light flux incident from the subject is controlled by the hole 21a provided in the diaphragm 21, and the imaging unit is in a fixed diaphragm state. . This fixed aperture value is F in the illustrated example.
8

On the other hand, when the shaft 23 of the bistable plunger 22 changes from the projecting state to the retracted state, the lever 24 rotates clockwise around the shaft hole of the bearing 24a, and its arm portion 24c rises. Arm 25a of lever 25
Is lifted and the lever 25 is rotated clockwise against the biasing force of the spring 30. When the lever 25 rotates in the clockwise direction, the diaphragm 21 moves the optical axis A of the lens 20 as shown by the dotted line.
Evacuate from. In this way, by retracting the diaphragm 21 from the optical axis A, the diaphragm of the imaging unit is opened. This open aperture device is F2 in the illustrated example.

When a subject is photographed by the electronic still camera having the image pickup section as described above, Ev as shown in FIG.
With reference to the diagram, the fixed aperture F8 or the aperture open F2 is selected according to the aperture value calculated by the photometric value. That is, when the aperture value is F2, the shaft 23 of the bistable plunger 22 is retracted, and the aperture 21 is retracted aside from the optical axis A. When the aperture value is F8, the shaft of the bistable plunger 22 is projected and the hole 21a of the aperture 21 is advanced on the optical axis A. In the Ev diagram shown in FIG. 6, when the brightness is in the range of Lv5 to Lv12 and the aperture value is F2 and the open aperture state is selected, the shutter speed is in the range of 1/8 seconds to 1/1000 seconds. The value is changed and the picture is taken. Further, when the brightness is in the range from Lv12 to Lv17 and the aperture value is F8 and the fixed aperture state is selected, the shutter speed exceeds 1/60 seconds and becomes 1/2.
It is variable within the range of up to 000 seconds and the image is taken.

Further, when an electronic still camera having the above-mentioned image pickup section displays an object on a monitor without taking a picture, it is desired to eliminate the fluctuation of the aperture value and fix the aperture value as much as possible in order to prevent hunting. . Therefore, when only the subject is displayed on the monitor, the Ev diagram shown in FIG. 3, in which the Ev diagram has hysteresis for aperture switching, is referred to. By referring to the Ev diagram in which hysteresis is provided for such aperture switching, the aperture value switching point due to the increase in brightness and the aperture value switching point due to the decrease in brightness are separated from each other. It is possible to eliminate hunting.

For example, in the Ev diagram shown in FIG. 3, the point at which the brightness rises and the aperture value changes from F2 to F8 is L.
The aperture value is v13, and the aperture value in the range from Lv5 to Lv13 is F2, and the aperture value in the range from Lv13 to Lv17 is F8. Aperture value F2 (luminance Lv5
In the range of Lv13), the shutter speed is 1/8 second to 1
/ 2000 seconds can be changed and set. Further, the aperture value F8 (exceeds the brightness Lv13 and exceeds Lv17
Up to 1), the shutter speed is 1/125 second to 1
/ 2000 seconds can be changed and set.

Further, in the Ev diagram shown in FIG. 3, the point at which the brightness decreases and the aperture value changes from F8 to F2 is L.
The aperture value is v11, the aperture value in the range of Lv5 to Lv11 is F2, and the aperture value in the range from Lv11 to Lv17 is F8. Aperture value F2 (luminance Lv5
In the range of Lv11), the shutter speed is 1/8 second to 1
/ 500 seconds can be changed and set.
Further, when the aperture value is F8 (the range from the brightness Lv11 to Lv17), the shutter speed is 1/30 seconds to 1/20.
It is possible to set it up to 00 seconds.

As described above, when the subject is not photographed and is displayed only on the monitor, the Ev diagram is provided with a diaphragm switching hysteresis so that the brightness is increased and the diaphragm value is changed from F2 to F8. Decreases and the aperture value changes from F8 to F2.
By separating the parts to be changed to
For example, even if the electronic still camera is used in an environment in which the brightness rises and falls from Lv12 within a short time in a short time, it is possible to eliminate frequent aperture changes.

Explaining with actual values, the luminance is L
Immediately after changing from v12 to Lv13 and changing the aperture value from F2 to F8, the brightness decreases again and changes from Lv13 to LV.
Even if it returns to 12, the aperture value in this case does not change and F
Maintained at 8. In order to return the aperture value from F8 to F2 again, it is necessary to significantly reduce the luminance from Lv13 (more than two scales) to Lv11 or less, but such a rapid change does not usually occur. On the contrary, even if the brightness is lowered again and returned from Lv11 to LV12 immediately after the brightness is changed from Lv12 to Lv11 and the aperture value is changed from F8 to F2, the aperture value in this case does not change and Will be maintained. To return the aperture value from F2 to F8 again, increase the brightness significantly from Lv11 (more than 2 scales) to L8.
It is necessary to be v13 or higher, but such a sudden change does not usually occur.

Therefore, F2 → F8 or F8 → F
As described in 2, it is possible to eliminate the frequent change of the aperture value, which causes the aperture 21 to advance to the optical axis A, or
It is possible to eliminate frequent repetition (hunting) of the operation of retracting the diaphragm 21 from the optical axis A. Also,
Since hunting can be eliminated, it can contribute to the reduction of power consumption.

Further, F2 → F8 or F8 → F2
When the aperture value changes and the aperture 21 operates,
The monitor 10 is controlled by the CPU 9 and the IPPV so that the monitor screen is turned off. This is to eliminate the noise caused by the driving of the motor and the fluctuation of the power supply due to the operation of the diaphragm 21, and the disturbance of the monitor image of the monitor 10 caused by the diaphragm 21 passing in front of the CCD. When the aperture value changes and the aperture 21 operates, the monitor image immediately before may be held without erasing the monitor screen, or the monitor image may be faded.

Next, the flow of the control mechanism of the diaphragm control device will be described. In FIG. 4A, when the aperture processing is started, it is first checked whether or not the monitoring by the monitor is started. If you want to start monitoring, go to the next step. If you do not want to start monitoring, jump to the beginning of this flow.

In the next step, initial values are set, such as setting the aperture value to F2 and the shutter speed to 1/1000.

In the next step, the CCD shutter is operated and the F value (aperture value) is calculated from the photometric value based on the output of the CCD. After the calculation of the F value, the processing of the F value set is performed. The processing for setting the F value is a subroutine as shown in FIG. The F value setting subroutine will be described below. In FIG. 4 (b),
When the F value setting subroutine starts, first, the monitor is turned off. Next, the set F value calculated from the photometric value is checked. When the set F value is F2 (open), the bistable plunger 22 is turned on by 50 mS in the positive direction, that is, the shaft 23 of the bistable plunger 22 shown in FIG.
Is operated toward the retracted (F2 direction) side to retract the diaphragm 21 from the optical axis A. When the set F value is F8, the bistable plunger 22 is turned on in the reverse direction by 50 mS, that is,
The shaft 23 of the bistable plunger 22 shown in FIG. 2 is projected (F8
Direction) to move the diaphragm 21 onto the optical axis A. As described above, after operating the bistable plunger 22 according to F2 and F8, the monitor is turned on again, and
Returning to the main flow shown in (a).

Upon completion of the F value setting subroutine, the photometric value shutter speed is calculated and the CC
The D shutter is activated. Then, the image is displayed on the monitor by the image processing, and the monitor is turned on.

In the next step, the shutter release (R
L) is checked. The shutter release is performed by pressing the shutter to the middle (RL1 is on),
Checked when the shutter is fully depressed (RL2 is on). Label_A is provided immediately before the shutter release is checked. First, it is checked whether RL1 is on. If it is off, proceed to the next step, and if it is on, Label
Jump to _B. In the next step, it is checked whether RL2 is on. If it is off, proceed to the next step, and if it is on, jump to Label_B.

In the next step where Label_D is provided, the F value is calculated from the photometric value and it is checked whether or not the F value is changed. When changing the F value, the above F value setting subroutine is processed. In this case, as a method of determining whether to change the F value, an Ev diagram having an aperture switching hysteresis as shown in FIG. 3 is used. For example, assuming that F2 is currently set, 20
Sampling of 0 mS is performed, and when the brightness is 150 mS or more and the brightness is Lv13 or more, the value is changed to F8. Alternatively, as it is currently set to F8, samples the 200 mS, to change to F2 when the luminance at least 150mS is Lv11 below.

In the next step, the shutter speed is calculated from the photometric value, the CCD shutter is operated, and the image processing (display on the monitor) is performed.
Jump to A. Note that unless RL1 or RL2 is turned on and jumps to Label_B (unless the shutter is pressed), the above flow is repeated and only the image of the subject is displayed on the monitor.

When either RL1 or RL2 is turned on, the process jumps to Label_B and the F value is calculated from the photometric value. In this case, Ev shown in FIG.
A diagram is used. At this point, RL1 is AE locked. In the next step, the F value setting subroutine is processed. After this, it is checked whether RL2 is on. Label_C is provided between the F value set and the check of RL2. If RL2 is on, calculate the shutter speed from the photometric value and CCD
After the shutter is operated, image processing (image recording on the memory card) is performed, and the aperture processing ends. If RL2 is off, check whether RL1 is on. RL
If 1 is on, the shutter speed is calculated from the photometric value, the CCD shutter is activated, and then image processing (displayed on the monitor) is performed to jump to Label_C. RL
If 1 is off, unlock the AE lock and LabelL_D
Jump to.

As another embodiment, the metering is sampled while the monitor is displayed, the shutter interlocking with the set aperture value is determined, and the aperture value is changed when it is determined that the shutter interlocking is large. You may do it. Even with such a configuration, there is an effect that power consumption increase and hunting due to the aperture change can be eliminated.

Further, although the above-mentioned diaphragm control device has been described as being used in an electronic still camera, it is not limited to this. Ru can be applied der to various different devices.

[0052]

According to the invention described in claim 1, the object
Moves on the optical axis or retracts outside the optical axis depending on the brightness
A diaphragm device that switches the diaphragm by
An image sensor that receives an image of the subject
Of an imaging device having a monitor that displays an image of a subject
When the monitor is displayed on the aperture controller , the aperture can be switched.
Since the shutter and the aperture are controlled by the EV diagram having hysteresis, the aperture value does not change frequently, and the increase of the aperture current and hunting can be eliminated. Also, while the image of the subject is displayed on the monitor, metering is performed to calculate the aperture value, and if the number of out-of-shutter shutters at the preset aperture value increases, the preset aperture value changes. Therefore, the aperture value does not change frequently, and the increase of the aperture current and the prevention of hunting can be eliminated.

[0053]

According to the second aspect of the present invention, since the monitor screen is turned off when the aperture is switched during the monitor display, the disorder of the monitor image can be eliminated.

According to the third aspect of the present invention, since the monitor screen is held when the aperture is switched during the monitor display, the disorder of the monitor image can be eliminated.

According to the fourth aspect of the present invention, when the aperture is switched during the monitor display, the monitor screen fades, so that the disorder of the monitor image can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a configuration of an electronic still camera in which an aperture control device according to the present invention is used.

FIG. 2 is a perspective view showing an embodiment of the above diaphragm control device by enlarging a main part.

FIG. 3 is an EV diagram with diaphragm switching hysteresis used in the diaphragm control device according to the present invention.

FIG. 4 is a flowchart showing the processing of the aperture control device according to the present invention.

FIG. 5 is a block diagram showing the configuration of an electronic still camera in which a conventional aperture control device is used.

FIG. 6 is an EV diagram used in the aperture control device.

Claims (4)

(57) [Claims] 1. The optical axis is advanced according to the brightness of the subject.
Or conversion El grain <br/> Ri device off throttle by retracted from the optical axis, the image pickup device an image of the object is input through the lens, the image is displayed in the object to be imaged to the image sensor A diaphragm control device for an image pickup apparatus having a monitor, wherein the shutter and the diaphragm device are controlled by an EV diagram having hysteresis in switching the diaphragm during monitor display, and an image of a subject is displayed in real time on the monitor. while,
When the aperture value is calculated by photometry and the number of out-of-shutter movements at the preset aperture value becomes large, the aperture device advances or retracts outside the optical axis and the preset aperture value is set. A diaphragm control device characterized by changing a value. 2. The monitor screen is turned off when the aperture is switched during the monitor display.
The diaphragm control device described. 3. The aperture control device according to claim 1, wherein the monitor screen is held when the aperture is switched during the monitor display. 4. The aperture control device according to claim 1, wherein the monitor screen is faded when the aperture is switched during the monitor display.