JP2005215206A - Imaging unit, imaging method, program, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce exposure variations due to the error in the diaphragm diameter, without making the response of an imaging unit deteriorated. <P>SOLUTION: In the imaging apparatus, shutter release time lag is reduced by omitting a photometric operation to be performed, in order to correct drive errors of diaphragm at the time of main exposure photography when the diaphragm value set at automatic focusing and the diaphragm value set at the main exposure photographing are the same. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for performing photometry in an imaging apparatus and determining an aperture value and a shutter speed.

Conventionally, a digital camera or the like has been provided with a diaphragm. However, there is a problem that the target diaphragm diameter is not large due to a mechanical error or the like when the diaphragm is operated. That is, even if an attempt is made to set the aperture, the diameter of the aperture is not set, and if the image is taken as it is, exposure variations will occur due to errors.
JP-A-9-15675

  As a countermeasure for the aperture diameter error, a method of performing a photometric operation after operating the aperture is known. That is, photometry is performed with the diameter of the stop including an error, the brightness is measured with the size of the diameter of the stop, and the shutter speed is determined so as to obtain an appropriate exposure.

  However, in this method, it is necessary to perform photometry after always operating the aperture, and there is a problem that the response of the camera is lowered because time is required for performing photometry.

  Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to reduce exposure variation due to an aperture diameter error without reducing the response of the imaging apparatus.

  In order to solve the above-described problems and achieve the object, an imaging apparatus according to the present invention includes an imaging unit that photoelectrically converts a subject image formed by a lens having a diaphragm, and an image signal output from the imaging unit. A first photometric means for performing a photometric operation for obtaining the subject brightness based on the first photometric value, and a first photometric operation for performing an autofocus operation for adjusting the focus of the lens based on the photometric value obtained by the first photometric means. First determining means for determining the aperture value and the first shutter speed, a second aperture value that is an actual aperture value when the aperture is operated with the first aperture value as a target value, and the Based on an image signal obtained by capturing a subject image at a first shutter speed, a second photometric unit that performs the photometric operation, a photometric value obtained by the second photometric unit, and the second aperture value. Then, based on the photometric value obtained by the second determining means for correcting the first shutter speed and determining the second shutter speed, and the photometric value obtained by the second photometric means, the main photographing of the imaging means A third determining means for determining a third aperture value and a third shutter speed for the first aperture, and a fourth aperture which is an actual aperture value when the aperture is operated with the third aperture value as a target value. A third photometric unit that performs the photometric operation based on an aperture value of the first image and an image signal obtained by capturing a subject image at the third shutter speed, a photometric value obtained by the third photometric unit, and the fourth photometric value. The fourth determining means for correcting the third shutter speed to determine the fourth shutter speed based on the aperture value, and the first aperture value and the third aperture value are the same. If the third measurement Without operation of the means and the fourth determining means, characterized by comprising a control means for performing the present photographing in and stop the second shutter speed without performing the driving.

  In the image pickup apparatus according to the present invention, the first determining means includes an autofocus indicating a relationship between a photometric value obtained by the first photometric means, an aperture value when performing an autofocus operation, and a shutter speed. The first aperture value and the first shutter speed are determined based on a program diagram for use.

  In the imaging apparatus according to the present invention, the third determining means may perform main photography indicating the relationship between the photometric value obtained by the second photometry means and the aperture value and shutter speed when performing the main photography operation. The third aperture value and the third shutter speed are determined based on the program diagram for operation.

  The image pickup apparatus according to the present invention further comprises autofocus means for picking up a subject image using the second aperture value and the second shutter speed and performing the autofocus operation. .

  In the image pickup apparatus according to the present invention, there is further provided a main photographing means for performing a main photographing using the third aperture value and the third shutter speed or the fourth aperture value and the fourth shutter speed. It is characterized by comprising.

  In addition, an imaging method according to the present invention includes an imaging process for photoelectrically converting a subject image formed by a lens having a diaphragm, and a photometric operation for obtaining subject brightness based on an image signal output in the imaging process. And a first aperture value and a first shutter speed for performing an autofocus operation for adjusting the focus of the lens based on the first photometric step and the photometric value obtained in the first photometric step. An image obtained by capturing a subject image with a first determination step, a second aperture value that is an actual aperture value when the aperture is operated with the first aperture value as a target value, and the first shutter speed A second photometry step for performing the photometry operation based on the signal, and the first shutter speed based on the photometry value obtained in the second photometry step and the second aperture value. And a third aperture for the actual photographing of the imaging means based on a second determination step of correcting the second shutter speed and determining a second shutter speed and a photometric value obtained in the second photometric step A third determination step of determining a value and a third shutter speed, a fourth aperture value that is an actual aperture value when the aperture is operated with the third aperture value as a target value, and the third A third photometric step of performing the photometric operation based on an image signal obtained by capturing a subject image at a shutter speed of the first, a photometric value obtained in the third photometric step, and the fourth aperture value, The fourth determination step of correcting the third shutter speed to determine the fourth shutter speed and the third aperture value are the same when the first aperture value and the third aperture value are the same. Perform photometry process and fourth determination process Not it, characterized by comprising a main imaging step of performing the present photographing in and stop the second shutter speed without performing the driving.

  In the imaging method according to the present invention, in the first determination step, an autofocus indicating a relationship between a photometric value obtained in the first photometry step, an aperture value when performing an autofocus operation, and a shutter speed. The first aperture value and the first shutter speed are determined based on a program diagram for use.

  Further, in the imaging method according to the present invention, in the third determination step, the main photographing showing the relationship between the photometric value obtained in the second photometric step, the aperture value when performing the main photographing operation, and the shutter speed. The third aperture value and the third shutter speed are determined based on the program diagram for operation.

  In addition, the imaging method according to the present invention further includes an autofocus step of imaging a subject image using the second aperture value and the second shutter speed and performing the autofocus operation. .

  A program according to the present invention causes a computer to execute the above imaging method.

  A storage medium according to the present invention stores the above-mentioned program so as to be readable by a computer.

  According to the present invention, it is possible to reduce the exposure variation due to the aperture diameter error without reducing the response of the imaging apparatus.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 100 denotes an imaging device. Reference numeral 10 denotes a photographing lens, 12 denotes a shutter having a diaphragm function, 14 denotes an image sensor that converts an optical image into an electrical signal, and 16 denotes an A / D converter that converts an analog signal output from the image sensor 14 into a digital signal.

  A timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16, and the D / A converter 26, and is controlled by the memory control circuit 22 and the system control circuit 50.

  An image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22.

  The image processing circuit 20 performs predetermined calculation processing using the captured image data, and the system control circuit 50 controls the exposure control unit 40 and the distance measurement control unit 42 based on the obtained calculation result. TTL (through-the-lens) AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-emission) processing are performed.

  Further, the image processing circuit 20 performs predetermined arithmetic processing using captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained arithmetic result.

  A memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32.

  The data of the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing circuit 20 and the memory control circuit 22 or the data of the A / D converter 16 is directly passed through the memory control circuit 22. It is.

  Reference numeral 24 denotes an image display memory, 26 denotes a D / A converter, 28 denotes an image display unit including a TFT LCD, and the image data for display written in the image display memory 24 passes through the D / A converter 26. Displayed by the image display unit 28.

  If the image data captured using the image display unit 28 is sequentially displayed, the electronic viewfinder function can be realized.

  Further, the image display unit 28 can arbitrarily turn on / off the display according to an instruction from the system control circuit 50. When the display is turned off, the power consumption of the imaging apparatus 100 can be significantly reduced. I can do it.

  Reference numeral 30 denotes a memory for storing captured still images and moving images, and has a sufficient storage capacity to store a predetermined number of still images and a predetermined time of moving images.

  Thereby, even in the case of continuous shooting or panoramic shooting in which a plurality of still images are continuously shot, it is possible to write a large amount of images to the memory 30 at high speed.

  The memory 30 can also be used as a work area for the system control circuit 50.

  A compression / decompression circuit 32 compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads an image stored in the memory 30, performs compression processing or decompression processing, and stores the processed data in the memory 30. Write to.

  Reference numeral 40 denotes an exposure control unit that controls the shutter 12 having an aperture function, and has a flash light control function in cooperation with the flash 48.

  Reference numeral 42 denotes a distance measurement control unit that controls focusing of the photographing lens 10, reference numeral 44 denotes a zoom control unit that controls zooming of the photographing lens 10, and reference numeral 46 denotes a barrier control unit that controls the operation of the protective device 102 serving as a barrier.

  A flash 48 has an AF auxiliary light projecting function and a flash light control function.

  The exposure control unit 40 and the distance measurement control unit 42 are controlled using the TTL method. Based on the calculation result obtained by calculating the captured image data by the image processing circuit 20, the system control circuit 50 performs the exposure control unit 40 and the distance measurement. The controller 42 is controlled.

  Reference numeral 50 denotes a system control circuit that controls the entire imaging apparatus 100, and 52 denotes a memory that stores constants, variables, programs, and the like for operation of the system control circuit 50.

  Reference numeral 54 denotes a display unit such as a liquid crystal display device or a speaker that displays an operation state or a message using characters, images, sounds, or the like in accordance with execution of a program in the system control circuit 50, and an operation unit of the imaging device 100 A single or a plurality of locations are provided in the vicinity where they can be easily seen, and are configured by a combination of, for example, an LCD, an LED, and a sounding element.

  In addition, the display unit 54 is partially installed in the optical viewfinder 104.

  Among the display contents of the display unit 54, what is displayed on the LCD or the like includes single shot / continuous shooting display, self-timer display, compression rate display, number of recorded pixels, number of recorded pixels, number of remaining images that can be captured, shutter Speed display, Aperture value display, Exposure compensation display, Flash display, Red-eye reduction display, Macro shooting display, Buzzer setting display, Clock battery level display, Battery level display, Error display, Multi-digit number information display and recording There are a display state of the media 200 and 210, a communication I / F operation display, a date / time display, and the like.

  Further, among the display contents of the display unit 54, what is displayed in the optical viewfinder 104 includes in-focus display, camera shake warning display, flash charge display, shutter speed display, aperture value display, exposure correction display, and the like.

  Reference numeral 56 denotes an electrically erasable / recordable nonvolatile memory such as an EEPROM.

  Reference numerals 60, 62, 64, 66, 68 and 70 are operation means for inputting various operation instructions of the system control circuit 50, and may be a single unit such as a switch, a dial, a touch panel, pointing by line-of-sight detection, a voice recognition device, or the like. Consists of multiple combinations.

  Here, a specific description of these operating means will be given.

  Reference numeral 60 denotes a mode dial switch, which can switch and set various function modes such as power-off, automatic shooting mode, shooting mode, panoramic shooting mode, playback mode, multi-screen playback / erase mode, and PC connection mode.

  Reference numeral 62 denotes a shutter switch SW1 which is turned on in the middle of the operation of the shutter button (half-pressing the shutter button), AF (autofocus) processing, AE (automatic exposure) processing, AWB (auto white balance) processing, EF (flash pre-flash). ) Instruct the start of operations such as processing.

  Reference numeral 64 denotes a shutter switch SW2, which is turned on when the operation of the shutter button is completed (the shutter button is fully pressed), and the signal read from the image sensor 12 is transferred to the memory 30 via the A / D converter 16 and the memory control circuit 22. Exposure processing to be written, development processing using computations in the image processing circuit 20 and the memory control circuit 22, image data is read from the memory 30, compressed by the compression / decompression circuit 32, and image data is stored in the recording medium 200 or 210. An instruction to start the operation of a series of processing called recording processing to be written is given.

  Reference numeral 66 denotes an image display ON / OFF switch that can set ON / OFF of the image display unit 28.

  With this function, when photographing is performed using the optical viewfinder 104, it is possible to save power by cutting off the power supply to the image display unit including a TFT LCD or the like.

  Reference numeral 68 denotes a quick review ON / OFF switch, which sets a quick review function for automatically reproducing image data taken immediately after photographing. In the present embodiment, in particular, a function for setting a quick review function when the image display unit 28 is turned off is provided.

  Reference numeral 70 denotes an operation unit composed of various buttons, a touch panel, and the like. A menu button, a set button, a macro button, a multi-screen playback page break button, a flash setting button, a single shooting / continuous shooting / self-timer switching button, menu movement + (plus) Button, menu movement-(minus) button, playback image movement + (plus) button, playback image movement-(minus) button, shooting quality selection button, exposure compensation button, date / time setting button, image deletion button, image deletion cancel There are buttons.

  A power control unit 80 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like. In addition, the DC-DC converter is controlled based on an instruction from the system control circuit 50, and a necessary voltage is supplied to each unit including the recording medium for a necessary period.

  Reference numeral 82 denotes a connector, 84 denotes a connector, and 86 denotes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, NiMH battery, or Li battery, an AC adapter, or the like.

  90 and 94 are interfaces with a recording medium such as a memory card and a hard disk, 92 and 96 are connectors for connecting to a recording medium such as a memory card and a hard disk, and 98 is a connector 92 and / or 96 with a recording medium 200 and / or 210. Is a recording medium attachment / detachment detection unit that detects whether or not the is attached.

  In the present embodiment, it is assumed that there are two systems of interfaces and connectors for attaching a recording medium. Of course, the interface and the connector for attaching the recording medium may have a single or a plurality of systems and any number of systems. Moreover, it is good also as a structure provided with combining the interface and connector of a different standard.

  The interface and connector may be configured using a PCMCIA card, a CF (Compact Flash (registered trademark)) card, or the like that conforms to a standard.

  Further, when the interfaces 90 and 94, and the connectors 92 and 96 are configured using a PCMCIA card, a CF card, or the like, a LAN card, a modem card, a USB card, an IEEE 1394 card, a P1284 card, a SCSI card, By connecting various communication cards such as a PHS communication card, image data and management information attached to the image data can be transferred to and from other computers and peripheral devices such as a printer.

  Reference numeral 102 denotes a protective device that is a barrier that prevents the imaging unit from being soiled or damaged by covering the imaging unit including the lens 10 of the imaging device 100.

  Reference numeral 104 denotes an optical viewfinder, which can take an image using only the optical viewfinder without using the electronic viewfinder function of the image display unit 28. In the optical viewfinder 104, some functions of the display unit 54, for example, a focus display, a camera shake warning display, a flash charge display, a shutter speed display, an aperture value display, an exposure correction display, and the like are installed.

  A communication unit 110 has various communication functions such as RS232C, USB, IEEE1394, P1284, SCSI, modem, LAN, and wireless communication.

  Reference numeral 112 denotes a connector for connecting the imaging apparatus 100 to another device by the communication unit 110 or an antenna in the case of wireless communication.

  Reference numeral 200 denotes a recording medium such as a memory card or a hard disk.

  The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, and the like, an interface 204 with the imaging device 100, and a connector 206 that connects to the imaging device 100.

  Reference numeral 210 denotes a recording medium such as a memory card or a hard disk.

  The recording medium 210 includes a recording unit 212 composed of a semiconductor memory, a magnetic disk, and the like, an interface 214 with the imaging device 100, and a connector 216 that connects to the imaging device 100.

  FIG. 2 is a perspective view when the imaging apparatus of the present embodiment is configured as an electronic camera.

  2-1 is a button for power ON / OFF. Reference numeral 2-2 denotes a mode switching lever which can switch and set each function mode such as a shooting mode, a playback mode, a moving image shooting mode, and a still image shooting mode. Reference numeral 2-3 denotes a shutter button.

  The captured image of the camera is displayed on the image display unit, which is usually referred to as an LCD since it normally uses an LCD (liquid crystal display). A screen for reproducing a still image and / or a moving image is also displayed on the LCD 2-4. Reference numeral 2-5 denotes a MENU button which is used to enter and exit a menu screen for changing shooting parameters and camera settings. 2-6 is a SET button, which is used for determining a menu. A delete button 2-7 can designate deletion of an image. Reference numeral 2-8 denotes a DISP button which is used to switch presence / absence of display on the LCD 2-4. Reference numeral 2-9 denotes a cross button, which is used to move items on the menu screen using the up / down / left / right buttons.

  Next, the operation flow of the imaging apparatus of the present embodiment will be described with reference to the flowcharts of FIGS.

  When the shutter switch SW1 of the image pickup apparatus is pressed, a photometric operation is performed in 201 (Step 1). The measured subject luminance value (Ev0) is sent to an AFP diagram 203 (autofocus program diagram), and an aperture value (Av0) and a shutter speed value (Tv0) for performing an autofocus operation are determined. (Step 2). In the AvTv control 202, the aperture is operated based on the determined aperture value (Step 3), and the shutter speed of the electronic shutter is set. However, although the aperture is operated with Av0 as a target here, since the mechanical error is included, the size of the aperture may not be completely Av0. Next, in photometry 204 (Step 4), photometry is performed with the actual aperture value (Av1) and electronic shutter (Tv0) when the aperture drive is performed with 202 as the target. From the measured brightness value (Ev1) and the actual aperture value (Av1), in the Tv control 205, a shutter speed value Tv1 is obtained so that the optimum exposure is obtained with the actual aperture value Av1 (Step 5). This concept is shown below.

  The relationship between the luminance values Ev0 measured in 201 and Av0 and Tv0 determined in 203 is expressed by equation (1).

Ev0 = Av0 + Tv0 (1)
That is, equation (1) means that in order to photograph a subject with Ev0, proper exposure is obtained if the subject is photographed with the aperture value Av0 and the shutter speed Tv0.

  If the actual aperture value driven by the aperture at 202 is Av1, and the luminance value measured at 204 is Ev1, the shutter speed Tv1 for obtaining an appropriate exposure with the actual aperture value (Av1) is as follows. Can be sought.

If Av1 = Av0 + ΔAv0, Ev1 = Av1 + Tv0 = (Av0 + ΔAv0) + Tv0, and thus ΔAv0 = Ev1-Ev0. However, since the actual luminance value of the subject is Ev0, Ev0 = Av1 + Tv1 is established. Should
Tv1 = Ev0−Av1 = Tv0−ΔAv0 (2)
By using the actual aperture value Av1 set in operation 202 and the shutter speed value Tv1 obtained in 205, the AF operation 206 is performed at an appropriate luminance level from which the aperture error has been removed. Although the AF operation is not described in detail here, the focus position is moved by a plurality of steps, and the focus position is set to the step having the highest frequency component (Step 6).

  When the AF operation is completed, an aperture value Av2 and a shutter speed Tv2 for performing imaging are determined in the imaging P diagram from the luminance values Ev1 to 208 measured in 204 (Step 7).

  In the determination of 207, the aperture value Av0 determined by the 203 AFP diagram (autofocus program diagram) is compared with the aperture value Av2 determined by the imaging P diagram of 208 (Step 8). Here, if Av0 and Av2 are equal, the shutter speed value Tv1 obtained in the Tv control of the aperture values Av2 and 205 is sent to 212 (Step 12). In this case, the aperture is not driven until the actual photographing is performed in Step 12 after the aperture is driven with Av0 as the target value in Step 3 and becomes the aperture value of Av1, and finally the value is set to Av1. Kept.

  If Av0 and Av2 are not equal in the determination of 207, the AvTv control of 209 operates the aperture based on the determined aperture value (Step 9) and sets the shutter speed. In this case as well, the aperture is operated with Av2 as a target, as in 202, but the size of the aperture may not be completely Av2 because it includes a mechanical error. Next, in the photometry of 210, photometry is performed with the actual aperture value (Av3) and electronic shutter (Tv2) when the aperture drive is performed with Av2 as the target in step 209 (Step 10). From the photometric brightness value (Ev3) and the actual aperture value (Av3), the shutter speed value Tv3 is obtained so that the optimum exposure is obtained with the actual aperture value Av3 in the Tv control of 211 (Step 11). This concept is shown below.

  The relationship between the brightness values Ev1 measured in 204 and Av2 and Tv2 determined in 208 is expressed by equation (3).

Ev1 = Av2 + Tv2 (3)
Further, if the actual aperture value set in operation 209 is Av3 and the luminance value measured in 210 is Ev3, the shutter speed Tv3 for obtaining proper exposure with the actual aperture value is expressed by equation (4) in 211. Is required.

When Av3 = Av2 + ΔAv2, since Ev1 = Av2 + Tv2, ΔAv2 = Ev3-Ev1, but since the luminance value of the subject is Ev1, it should be set so that Ev1 = Av3 + Tv3 holds.
Tv3 = Tv2- (Ev3-Ev1) = Ev1-Av3 = Tv2-ΔAv2 (4)
The shutter speed value Tv3 obtained in 211 and the actual aperture value Av3 set for operation in 209 are sent to 211.

  The above is the operation when SW1 is pressed. When the shutter switch SW2 is further pressed, shooting is performed with the aperture value and shutter speed value set in 212 (Step 12).

  As described above, according to the above-described embodiment, when the aperture value set at the time of autofocus and the aperture value used at the time of imaging are the same, the imaging device is operated in a sequence that does not perform the photometric operation for eliminating the aperture error. Therefore, the shutter release time lag can be reduced.

(Other embodiments)
In addition, an object of each embodiment is to supply a storage medium (or recording medium) on which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and a computer (or CPU) of the system or apparatus Needless to say, this can also be achieved by reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Furthermore, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function is determined based on the instruction of the program code. It goes without saying that the CPU or the like provided in the expansion card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

1 is a block diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention. It is a perspective view at the time of comprising the imaging device of one embodiment as an electronic camera. It is a figure for demonstrating the flow of operation | movement of the imaging device of one Embodiment. It is a flowchart for demonstrating the flow of operation | movement of the imaging device of one Embodiment.

Claims (11)

Imaging means for photoelectrically converting a subject image formed by a lens having an aperture; and
First photometry means for performing photometry operation for obtaining subject luminance based on an image signal output from the imaging means;
First determining means for determining a first aperture value and a first shutter speed when performing an autofocus operation for adjusting the focus of the lens based on a photometric value obtained by the first photometric means; ,
The photometric operation based on a second aperture value, which is an actual aperture value when the aperture is operated using the first aperture value as a target value, and an image signal obtained by capturing a subject image at the first shutter speed. A second photometric means for performing
Second determining means for correcting the first shutter speed and determining the second shutter speed based on the photometric value obtained by the second photometric means and the second aperture value;
Third determining means for determining a third aperture value and a third shutter speed for the actual photographing of the imaging means based on the photometric value obtained by the second photometric means;
The photometric operation based on a fourth aperture value, which is an actual aperture value when the aperture is operated with the third aperture value as a target value, and an image signal obtained by capturing a subject image at the third shutter speed. A third photometric means for performing
Fourth determining means for correcting the third shutter speed based on the photometric value obtained by the third photometric means and the fourth aperture value to determine the fourth shutter speed;
When the first aperture value and the third aperture value are the same, the second photometric means and the fourth determining means are not operated, and the second aperture value is not driven. An image pickup apparatus comprising: control means for performing the main photographing at a shutter speed.   The first determining means is based on a photometric value obtained by the first photometric means and an autofocus program diagram showing a relationship between an aperture value and a shutter speed when performing an autofocus operation. The imaging apparatus according to claim 1, wherein the first aperture value and the first shutter speed are determined.   The third determining means is based on the photometric value obtained by the second photometric means and the main photographing program diagram showing the relationship between the aperture value and the shutter speed when performing the main photographing operation. The imaging apparatus according to claim 1, wherein a third aperture value and a third shutter speed are determined.   The imaging apparatus according to claim 1, further comprising: an autofocus unit that captures a subject image using the second aperture value and the second shutter speed and performs the autofocus operation.   2. The apparatus according to claim 1, further comprising a main photographing unit that performs a main photographing using the third aperture value and the third shutter speed or the fourth aperture value and the fourth shutter speed. The imaging device described in 1. An imaging process for photoelectrically converting a subject image formed by a lens having a diaphragm;
A first photometric step of performing a photometric operation for obtaining subject luminance based on an image signal output in the imaging step;
A first determination step for determining a first aperture value and a first shutter speed when performing an autofocus operation for adjusting the focus of the lens based on the photometric value obtained in the first photometric step; ,
The photometric operation based on a second aperture value, which is an actual aperture value when the aperture is operated using the first aperture value as a target value, and an image signal obtained by capturing a subject image at the first shutter speed. A second photometric step of performing
A second determining step of correcting the first shutter speed and determining a second shutter speed based on the photometric value obtained in the second photometric step and the second aperture value;
A third determination step of determining a third aperture value and a third shutter speed for the actual photographing of the imaging means based on the photometric value obtained in the second photometric step;
The photometric operation based on a fourth aperture value, which is an actual aperture value when the aperture is operated with the third aperture value as a target value, and an image signal obtained by capturing a subject image at the third shutter speed. A third photometric step of performing
A fourth determining step of correcting the third shutter speed based on the photometric value obtained in the third photometric step and the fourth aperture value to determine the fourth shutter speed;
When the first aperture value and the third aperture value are the same, the second shutter speed is not performed without performing the third photometry step and the fourth determination step, and without performing aperture driving. And a main photographing step of performing the main photographing.   In the first determining step, based on the photometric value obtained in the first photometric step and the autofocus program diagram showing the relationship between the aperture value and the shutter speed when performing the autofocus operation, The imaging method according to claim 6, wherein the first aperture value and the first shutter speed are determined.   In the third determining step, based on the photometric value obtained in the second photometric step and the main photographing program diagram showing the relationship between the aperture value and the shutter speed when performing the main photographing operation, The imaging method according to claim 6, wherein the third aperture value and the third shutter speed are determined.   The imaging method according to claim 6, further comprising an autofocus step of capturing an object image using the second aperture value and the second shutter speed and performing the autofocus operation.   A program for causing a computer to execute the imaging method according to any one of claims 6 to 9.   A storage medium storing the program according to claim 10 in a computer-readable manner.

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