JP6929140B2 - Control device, image pickup device, control method, program, and storage medium - Google Patents

Description

The present invention relates to an imaging device that performs focus detection.

In recent years, as phase-difference AF (imaging surface phase-difference AF) using an image sensor, a method of acquiring a captured image and performing focus detection using the pixels of the image sensor has been proposed. According to the image pickup surface phase difference AF, the subject can be detected and the focus can be adjusted based on the signals obtained from the same image sensor, so that the focus can be adjusted at high speed and with high accuracy.

Patent Document 1 discloses a configuration in which a plurality of photodiodes corresponding to one microlens are provided, and each photodiode receives light from different pupil surfaces of the photographing lens. With such a configuration, the imaging surface phase difference AF can be performed by comparing the outputs of the two photodiodes.

Patent Document 2 discloses a configuration in which a sensitivity region of a light receiving portion is eccentric with respect to the optical axis of an on-chip microlens to impart a pupil division function in some pixels of an image pickup device. By using these pixels as focus detection pixels and arranging the focus detection pixels between the photographing pixel groups at predetermined intervals, the imaging surface phase difference AF can be performed. Here, since the location where the focus detection pixel is arranged corresponds to the missing portion of the shooting pixel, the image information is generated by interpolating from the information of the peripheral shooting pixels. With such a configuration, since the phase difference can be detected on the imaging surface, it is possible to perform high-speed and high-precision focus adjustment even when observing with an electronic finder or shooting a moving image.

Japanese Unexamined Patent Publication No. 2001-083407 Japanese Unexamined Patent Publication No. 2009-003122

However, in reality, the detection characteristics differ greatly depending on the evaluation band of the signal waveform used in the correlation calculation. Further, particularly in the case of the imaging surface phase difference AF, it is necessary to perform the correlation calculation in synchronization with the imaging signal, so that the correlation calculation time allowed for one image is limited. For this reason, a signal with a low-frequency filter applied is used to widen the detection range during the direction detection operation during large blurring, while a signal with a high-frequency filter applied during the focusing operation near in-focus. It is necessary to increase the detection accuracy by using. That is, the detection characteristics suitable for performing stable, high-speed, and highly accurate focus adjustment differ depending on the state of the focus adjustment operation.

Therefore, the present invention provides a control device, an imaging device, a control method, a program, and a storage medium capable of stable, high-speed, and highly accurate focus adjustment.

The control device as one aspect of the present invention includes a calculation means for calculating the defocus amount based on the first signal and the second signal corresponding to the light beams passing through different pupil regions of the imaging optical system, and the defocus amount. The focus adjusting means has a focus adjusting means for performing the focus adjusting operation based on the above, and the focus adjusting means is one from a plurality of drive modes for performing the focus adjusting operation based on the comparison result of the defocus amount and the threshold value. A drive mode is selected, and the characteristics relating to the frequency bands of the first signal and the second signal used by the calculation means for calculating the defocus amount are changed according to the selected drive mode, and the plurality of drives are used. The modes are the first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped, and the modes are acquired during the drive of the focus lens. An image under a predetermined condition rather than the threshold value when the imaging optical system is in the first imaging state, including a second drive mode in which the focus adjustment operation is performed using the first signal and the second signal. The threshold value in the second imaging state in which the amount of surface movement is larger than that in the first imaging state is larger .

The imaging device as another aspect of the present invention includes an imaging element having a first photoelectric conversion unit and a second photoelectric conversion unit that receive light rays passing through different pupil regions of the imaging optical system, and the first photoelectric conversion unit. A calculation means for calculating the defocus amount based on the first signal and the second signal corresponding to the output signals from the second photoelectric conversion unit, and focus adjustment for performing the focus adjustment operation based on the defocus amount. The focus adjusting means selects one drive mode from a plurality of drive modes for performing the focus adjustment operation based on the comparison result of the defocus amount and the threshold value, and is selected. Depending on the drive mode, the characteristics regarding the frequency bands of the first signal and the second signal used by the calculation means for calculating the defocus amount are changed, and the plurality of drive modes are the focus lenses of the imaging optical system. The first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens is stopped, and the first signal and the second signal acquired while the focus lens is being driven. The image plane movement amount under a predetermined condition is larger than the threshold value when the imaging optical system is in the first imaging state, including the second drive mode in which the focus adjustment operation is performed using the first imaging state. The threshold value is larger in the second imaging state .

The control method as another aspect of the present invention includes a step of calculating the defocus amount based on the first signal and the second signal corresponding to the light beams passing through different pupil regions of the imaging optical system, and the defocus amount. It has a step of performing the focus adjustment operation based on the above, and in the step of performing the focus adjustment operation, one of a plurality of drive modes for performing the focus adjustment operation based on the comparison result of the defocus amount and the threshold value. One drive mode is selected, and the characteristics relating to the frequency bands of the first signal and the second signal used for calculating the defocus amount in the calculation step are changed according to the selected drive mode. The drive modes are the first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped, and during the drive of the focus lens. The first signal and the second drive mode in which the focus adjustment operation is performed using the acquired second signal are included, and a predetermined condition is set more than the threshold value when the imaging optical system is in the first photographing state. The threshold value in the second imaging state in which the image plane movement amount in the above is larger than that in the first imaging state is larger .

A program as another aspect of the present invention causes a computer to execute the control method.

A storage medium as another aspect of the present invention stores the program.

Other objects and features of the present invention will be described in the following embodiments.

According to the present invention, it is possible to provide a control device, an image pickup device, a control method, a program, and a storage medium capable of stable, high-speed and highly accurate focus adjustment.

It is a block diagram of the image pickup apparatus in each embodiment. It is a relationship diagram of the detection accuracy and the detection defocus amount for each band of an AF signal. It is a figure which shows the pixel composition example of (a) non-imaging surface phase difference system and (b) imaging surface phase difference system. It is a flowchart which shows the focus adjustment operation in each 1st and 2nd Embodiment. It is explanatory drawing about the detection characteristic setting in each embodiment. It is a flowchart which shows the focus detection process in each embodiment. It is explanatory drawing of the focus detection area in each embodiment. It is explanatory drawing of the AF signal (a pair of image signals) in each embodiment. It is explanatory drawing of the relationship between the shift amount and the correlation amount of the AF signal in each embodiment. It is explanatory drawing of the relationship between the shift amount of the AF signal and the correlation change amount in each embodiment. It is a flowchart which shows the setting of the detection characteristic in 2nd Embodiment. It is a flowchart which shows the focus adjustment operation in 3rd Embodiment. It is explanatory drawing of the relationship between the reliability and the detection defocus amount in the 3rd Embodiment.

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

(First Embodiment)
First, the configuration of the image pickup apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an image pickup apparatus 100 (interchangeable lens camera system) according to the present embodiment. The image pickup device 100 includes a camera body 20 (imaging device body) and a lens unit 10 (interchangeable lens) that can be attached to and detached from the camera body 20. The lens control unit 106 that controls the overall operation of the lens unit 10 and the camera control unit 212 that controls the overall operation of the image pickup device 100 (camera system) including the lens unit 10 are terminals provided on the lens mount. It is possible to communicate with each other via (not shown). The present embodiment can also be applied to an imaging device in which a lens unit and a camera body are integrally configured.

First, the configuration of the lens unit 10 will be described. The fixed lens 101, the aperture 102, and the focus lens 103 constitute an imaging optical system. The diaphragm 102 is driven by the diaphragm drive unit 104 and controls the amount of light incident on the image sensor 201, which will be described later. The focus lens 103 is driven by the focus lens driving unit 105, and the focusing distance of the imaging optical system changes according to the position of the focus lens 103. The aperture drive unit 104 and the focus lens drive unit 105 are controlled by the lens control unit 106, and determine the aperture amount of the aperture 102 and the position of the focus lens 103, respectively.

The lens operation unit 107 is an input for the user to make settings related to the operation of the lens unit 10, such as switching between AF (autofocus) / MF (manual focus) modes, adjusting the position of the focus lens 103 by MF, and setting the camera shake correction mode. It is a group of devices. When the lens operation unit 107 is operated by the user, the lens control unit 106 performs control according to the operation. The lens control unit 106 controls the aperture drive unit 104 and the focus lens drive unit 105 in response to control commands and control information received from the camera control unit 212, which will be described later. Further, the lens control unit 106 transmits the lens control information to the camera control unit 212.

Next, the configuration of the camera body 20 will be described. The camera body 20 is configured to acquire an image pickup signal from a luminous flux that has passed through the image pickup optical system of the lens unit 10. The image sensor 201 includes a CCD sensor, a CMOS sensor, and the like, and photoelectrically converts a subject image (optical image) formed via the image pickup optical system of the lens unit 10 to output a pixel signal (image data). That is, the luminous flux incident from the image pickup optical system is imaged on the light receiving surface of the image pickup element 201, and is converted into a signal charge according to the amount of incident light by the pixels (photodiodes) arranged in the image pickup element 201. The signal charge accumulated in each photodiode is sequentially read from the image sensor 201 as a voltage signal corresponding to the signal charge based on the drive pulse output from the timing generator 214 according to the command of the camera control unit 212.

Each pixel of the image sensor 201 used in the present embodiment is provided for two (pair) photodiodes A and B and these pair of photodiodes A and B (sharing photodiodes A and B). It is configured to include one microlens. That is, the image sensor 201 has a pair of photodiodes (first photoelectric conversion unit and second photoelectric conversion unit) for one microlens, and a plurality of microlenses are arranged two-dimensionally. Each pixel divides the incident light with a microlens to form a pair of optical images on the pair of photodiodes A and B, and the pair of photodiodes A and B form a pair of AF signals to be described later. Outputs pixel signals (A image signal and B image signal). Further, by adding the outputs of the pair of photodiodes A and B, an imaging signal (A + B image signal) can be obtained.

AF signals (focus detection) used for AF (imaging surface phase difference AF) by the imaging surface phase difference detection method by synthesizing a plurality of A image signals and a plurality of B image signals output from a plurality of pixels. A pair of image signals as a signal) can be obtained. The AF signal processing unit 204, which will be described later, performs a correlation calculation on the pair of image signals, calculates the phase difference (image shift amount) which is the shift amount of the pair of image signals, and further deduces the imaging optical system from the image shift amount. Calculate the focus amount (and defocus direction).

In this way, the image pickup device 201 photoelectrically converts the optical image formed by receiving the light flux passing through the image pickup optical system of the lens unit 10 into an electric signal, and outputs image data (image signal). The image sensor 201 of the present embodiment is provided with two photodiodes for one microlens, and can generate an image signal used for focus detection by the imaging surface phase difference AF method. The number of photodiodes (divided PDs) sharing one microlens may be changed, such as providing four photodiodes for one microlens.

FIG. 3A schematically shows a pixel configuration that does not support the imaging surface phase-difference AF method, and FIG. 3B schematically shows a pixel configuration example that supports the imaging surface phase-difference AF method. The Bayer array is used in both the pixel configurations of FIGS. 3A and 3B, where R is a red color filter, B is a blue color filter, and Gr and Gb are green color filters. Shown. In the pixel configuration of FIG. 3 (b) corresponding to the imaging surface phase difference AF, within one pixel (pixel shown by the solid line) in the pixel configuration not compatible with the imaging surface phase difference AF method shown in FIG. 3 (a). , Two photodiodes A and B divided into two in the horizontal direction of FIG. 3B are provided. The photodiodes A and B (first photoelectric conversion unit and second photoelectric conversion unit) receive light flux that has passed through different pupil regions of the imaging optical system. Since the photodiode A and the photodiode B receive the luminous flux that has passed through different regions of the exit pupil of the photographing optical system, the B image signal has parallax with respect to the A image signal. The pixel division method shown in FIG. 3B is an example, such as a configuration in which the pixels are divided in the vertical direction in FIG. Other configurations may be adopted. Further, a plurality of types of pixels divided by different division methods may be included in the same image pickup device.

In the present embodiment, a plurality of photoelectric conversion units are arranged for one microlens, and the pupil-divided light flux is incident on each photoelectric conversion unit, but the present invention is limited to this. It's not a thing. For example, the configuration of the focus detection pixel may be such that one PD is provided under the microlens and the pupil is divided by shading the left and right or the top and bottom with a light shielding layer. Further, a pair of focus detection pixels may be discretely arranged in an array of a plurality of image pickup pixels, and a pair of image signals may be acquired from the pair of focus detection pixels.

The CDS / AGC / AD converter 202 performs correlated double sampling, gain adjustment, and AD conversion for removing reset noise on the AF signal and the imaging signal read from the image sensor 201. The CDS / AGC / AD converter 202 outputs each of the image pickup signal and the AF signal that have undergone these processes to the image input controller 203 and the AF signal processing unit 204.

The image input controller 203 stores the imaging signal output from the CDS / AGC / AD converter 202 in the SDRAM 209 via the bus 21 as an image signal. The image signal stored in the SDRAM 209 is read by the display control unit 205 via the bus 21 and displayed on the display unit 206. In the recording mode for recording the image signal, the image signal stored in the SDRAM 209 is recorded in the recording medium 208 such as a semiconductor memory by the recording medium control unit 207. The ROM 210 stores a control program and a processing program executed by the camera control unit 212 (focus adjustment means), and various data necessary for executing these programs. The flash ROM 211 stores various setting information related to the operation of the camera body 20 set by the user.

The subject detection unit 2121 of the camera control unit 212 detects a specific subject based on the imaging signal input from the image input controller 203, and determines the position of the specific subject in the imaging signal. Further, the subject detection unit 2121 continuously inputs an imaging signal from the image input controller 203, and when the detected specific subject moves, determines the position of the destination subject. In this way, the subject detection unit 2121 follows the position of a specific subject. The specific subject is, for example, a face subject, a subject existing at a position designated by the user on the imaging screen via the camera operation unit 213, or the like. As will be described later, the information regarding the position and size of the detected specific subject is mainly used to set the area for performing AF (focus detection area).

The AF signal processing unit 204 (calculation means) performs a correlation calculation on a pair of image signals which are AF signals output from the CDS / AGC / AD converter 202, and performs an image shift amount and reliability of the pair of image signals. Is calculated. The reliability is calculated by using the degree of coincidence of two images (a pair of image signals) described later and the steepness of the amount of correlation change. Further, the AF signal processing unit 204 sets the position and size of the focus detection region, which is a region for performing focus detection and AF in the imaging screen. The AF signal processing unit 204 outputs information on the image shift amount (detection amount) and reliability calculated in the focus detection region to the camera control unit 212. The details of the processing performed by the AF signal processing unit 204 will be described later.

The AF control unit 2122 in the camera control unit 212 is, if necessary, based on the image shift amount and reliability calculated by the AF signal processing unit 204 and the information indicating the state of the lens unit 10 and the camera body 20. The setting of the AF signal processing unit 204 is changed. For example, when the image shift amount is equal to or greater than a predetermined amount, the AF control unit 2122 sets the area for performing the correlation calculation wider than the area set by the AF signal processing unit 204, or sets the contrast of the pair of image signals. Change the type of bandpass filter accordingly. Further, the AF control unit 2122 is designated in the image pickup screen by the user via the specific subject detected by the subject detection unit 2121 or the camera operation unit 213 in order to set the focus detection area by the AF signal processing unit 204. The position is passed to the AF signal processing unit 204. As a result, the AF control unit 2122 and the AF signal processing unit 204 can set the position and range of the focus detection region based on this information.

In the present embodiment, the camera control unit 212 receives a total of three signals from the image sensor 201, an image pickup signal (A + B image signal) and a pair of image signals (A image signal, B image signal) which are AF signals. get. However, in consideration of the load of the image sensor 201, the camera control unit 212 extracts from the image sensor 201, for example, a total of two signals, an image pickup signal (A + B image signal) and one AF signal (A image signal). It may be configured as. In this case, the camera control unit 212 converts the difference between the extracted imaging signal and the AF image signal ((A + B image signal) − (A image signal)) into another AF image signal (B image signal). Can be calculated and used as. The imaging signal (A + B image signal) and one image signal (A image signal or B image signal) also have parallax.

The camera control unit 212 controls each unit while exchanging information with each unit in the camera body 20. Further, the camera control unit 212 can be used for user operations such as power ON / OFF, change of various settings, imaging processing, AF processing, and recording image reproduction processing in response to an input from the camera operation unit 213 based on the user's operation. Perform various corresponding processes. Further, the camera control unit 212 transmits a control command to the lens unit 10 (lens control unit 106) and information on the camera body 20 to the lens control unit 106, and acquires information on the lens unit 10 from the lens control unit 106. The camera control unit 212 is configured to include a microcomputer, and controls the entire camera system including the lens unit 10 by executing a computer program stored in the ROM 210. Further, the camera control unit 212 calculates the defocus amount using the image shift amount in the focus detection region calculated by the AF signal processing unit 204, and uses the lens control unit 106 based on the calculated defocus amount. Controls the drive of the focus lens 103.

Next, the focus adjustment operation (focus control) in the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the procedure of the focus adjustment operation. Each step in FIG. 4 is executed by the camera control unit 212 (mainly the AF control unit 2122) according to a computer program (imaging process program).

First, in step S401, the camera control unit 212 determines whether or not to execute the focus adjustment operation according to the setting of the camera body 20 and the input signal from the camera operation unit 213. Step S401 is repeated until the focus adjustment operation is started. If it is determined that the camera control unit 212 executes the focus adjustment operation, the process proceeds to step S402. In step S402, the camera control unit 212 exposes the image sensor 201 to acquire the AF signal used for the imaging surface phase difference AF and the imaging signal used for the live view display, and performs live view shooting. Run.

Subsequently, in step S403, the camera control unit 212 sets an appropriate detection characteristic (frequency band of the image signal used for focus detection) according to the current setting of the camera body 20 and the control state (drive mode) of the focus adjustment operation. Set. As shown in FIG. 5, for example, the camera control unit 212 simultaneously performs focus detection based on a combination of AF operation, control state (drive mode), and AF mode (type of focus adjustment operation). Determine the number of and the evaluation band (frequency band of the image signal) to be used. The AF operation and AF mode are set by receiving input from the user, for example. Further, as the control state, the result selected in response to the focus detection result in the previous frame is used.

FIG. 5 is an explanatory diagram regarding the detection characteristic setting (setting of the focus detection characteristic). In FIG. 5, the AF operation includes one-shot AF, servo AF, and continuous AF. The control state (drive mode) includes focus stop, target drive, defocus drive, and search drive. AF modes include one-point AF, face AF, zone AF, and autoselect AF. In FIG. 5, the numbers such as 1 point and 9 points indicate the number of focus detection regions that simultaneously perform focus detection. The evaluation band of the focus adjustment operation can be changed according to the type of filter applied to the image signal, and in the present embodiment, three bands of high range, mid range, and low range are used as the evaluation band. Have.

The high range, mid range, and low range are evaluation bands (frequency bands) of the AF signal (signal waveform) used in the correlation calculation. Here, with reference to FIG. 2, the characteristics of the high range, the mid range, and the low range (high range signal, mid range signal, low range signal) will be described. FIG. 2 is a relationship diagram between the detection accuracy and the detection defocus amount for each evaluation band of the AF signal. The vertical axis shows the detection accuracy and the horizontal axis shows the detection defocus amount. As shown in FIG. 2, the high frequency signal has high detection accuracy, but the range of the detected defocus amount (detectable range of the defocus amount) is narrow. Therefore, the high frequency signal is suitable for focusing in the vicinity of the in-focus state. On the other hand, the low frequency signal has a wide range of detection defocus amount, but the detection accuracy is low. Therefore, the low frequency signal is suitable for the direction detection operation at the time of large blur. Further, the mid-frequency signal has characteristics intermediate between both the high-frequency signal and the low-frequency signal.

In FIG. 5, for example, the case where the AF operation is one-shot AF and the AF mode is set to one-point AF or face AF that performs a focus adjustment operation for one predetermined focus detection region will be focused on. At this time, since the calculation target area is limited, the camera control unit 212 sets all the evaluation bands of the high range, the middle range, and the low range within a predetermined processing time regardless of the control state of the focus adjustment operation. It is possible to calculate to. On the other hand, in the case of zone AF or automatic selection AF, in which it is necessary to perform the main area selection operation in parallel with the focus adjustment operation while calculating a plurality of focus detection areas at the same time, all evaluation bands are calculated within a predetermined processing time. It's difficult to do. Therefore, it is necessary to effectively switch (select) the evaluation band to be calculated according to the control state.

Further, in FIG. 5, attention is paid to a case where, for example, the AF mode is set to the face AF mode. At this time, in the case of one-shot AF assuming that the subject is stationary during the focus adjustment operation, the calculation target area can be limited. Therefore, it is possible to calculate all the evaluation bands of the high region, the mid region, and the low region within a predetermined processing time regardless of the control state of the focus adjustment operation. On the other hand, in the case of servo AF or continuous AF that assumes that the subject is moving during the focus adjustment operation, it is necessary to perform the main area selection operation in parallel with the focus adjustment operation while calculating a plurality of focus detection areas at the same time. There is. Therefore, it is difficult to calculate all the evaluation bands within a predetermined processing time, and it is necessary to effectively switch (select) the evaluation band to be calculated according to the control state.

In the present embodiment, the types of AF operation, control state, and AF mode are not limited to these, and a configuration that does not include some of these, other AF operation, control state, or AF mode It may be a configuration including. Further, in the present embodiment, the evaluation band is not limited to the three bands of high range, mid range, and low range, and may have two bands or four or more bands.

Subsequently, in step S404, the AF signal processing unit 204 performs focus detection processing based on a command from the camera control unit 212 (AF control unit 2122). The focus detection process is a process for acquiring information on the defocus amount and reliability (correlation reliability) for performing imaging surface phase difference AF. Further, the detection characteristics set for the area (focus detection area) in the imaging screen for acquiring information in the focus detection process are set according to the control state of the camera body 20 and the like. The details of the focus detection process will be described later.

Subsequently, in step S405, the camera control unit 212 (AF control unit 2122) determines whether or not the processing of steps S403 and S404 has been performed for all the set focus detection regions. If there is a focus detection area in which the processes of steps S403 and S404 have not been performed, the process returns to step S403, and the AF control unit 2122 performs the processes of steps S403 and S404 with respect to the focus detection area that has not yet been processed. On the other hand, when the processes of steps S403 and S404 are performed for all the focus detection regions, the process proceeds to step S406.

In step S406, the camera control unit 212 (AF control unit 2122) targets the focus adjustment operation based on the reliability (correlation reliability) and the amount of detection defocus for each focus detection region calculated in step S404. Select the main area (primary focus detection area) to be used. Step S406 is mainly required when the AF mode is zone AF or automatic selection AF. There are various methods for selecting the main area, such as face position priority, close-up priority, and center priority, but in the present embodiment, any method can be used depending on the application. When the AF mode is one-point AF or face AF and only one focus detection area exists, that one focus detection area may be set as the main area.

Subsequently, in steps S407 to S410, the drive control to be performed is selected according to the reliability of the focus detection and the defocus amount obtained by the focus detection. The selection result here is used for the detection characteristic setting (S403) for the image acquired in the next frame. In step S407, the camera control unit 212 (AF control unit 2122) determines whether or not the reliability of the main region selected in step S406 is equal to or greater than the second reliability threshold value. Reliability is determined by the degree of coincidence between the two images and the steepness of the amount of image shift described above. In the present embodiment, as the second reliability threshold value, it is preferable to set the maximum value of the reliability range in which the calculated defocus amount cannot be trusted. The reliability can be determined by using both or one (that is, at least one) of the degree of coincidence between the two images and the steepness of the amount of image shift. The reliability may also be determined using other indicators such as the signal level of the two images.

If it is determined in step S407 that the reliability is equal to or higher than the second reliability threshold value, the process proceeds to step S408, and the AF control unit 2122 has a reliability equal to or higher than the first reliability threshold value higher than the second reliability threshold value. Determine if it exists. The first reliability threshold value is determined based on the calculated detection variation of the defocus amount, and it is preferable to set the maximum value of the reliability range for which the focusing accuracy cannot be guaranteed.

If it is determined in step S408 that the reliability is equal to or higher than the first reliability threshold value, the process proceeds to step S409. In step S409, the AF control unit 2122 determines whether or not the defocus amount (detection defocus amount) calculated for the main region selected in step S406 is within the second defocus threshold value. The second defocus threshold is determined based on the calculated defocus amount, and is within the defocus range in which the defocus amount can be detected even when the above-mentioned evaluation band is switched to a high region where the detection range of the defocus amount is narrow. It is preferable to set the maximum value.

If it is determined that the detected defocus amount is within the second defocus threshold, the process proceeds to step S410, and the AF control unit 2122 has the AF control unit 2122 within the first defocus threshold where the detected defocus amount is smaller than the second defocus threshold. It is determined whether or not it is. The first defocus threshold value is determined based on the depth of focus, and it is preferable to set the maximum value of the defocus range that can be determined to be in the in-focus state.

If it is determined in step S410 that the detected defocus amount is within the first defocus threshold value, the process proceeds to step S411. In step S411, the AF control unit 2122 determines that the subject can be focused (in the focused state), and stops the focus lens 103 (stops focusing). On the other hand, if it is determined that the detected defocus amount is not within the first defocus threshold value, the process proceeds to step S412. In step S412, the AF control unit 2122 calculates the drive amount of the focus lens 103 based on the detected defocus amount, and drives the target lens 103 intermittently via the focus lens drive unit 105. The target drive is a drive that exclusively performs the focus detection process and the focus lens control (focus lens drive) in order to improve the detection accuracy and the control accuracy in the focus adjustment. That is, in the target drive, focus detection is performed using the image signal acquired while the focus lens is stopped.

If it is determined in step S408 that the reliability is not equal to or higher than the first reliability threshold value, or if it is determined in step S409 that the detected defocus amount is not within the second defocus threshold value, the process proceeds to step S413. In step S413, the AF control unit 2122 calculates the drive amount of the focus lens 103 based on the detected defocus amount, and performs defocus drive for continuously driving the focus lens 103 via the focus lens drive unit 105. .. The defocus drive is a drive in which the focus detection process and the focus lens control (focus lens drive) are performed in parallel, giving priority to speed over accuracy. That is, in the defocus drive, focus detection is performed using the image signal acquired while the focus lens is being driven.

If it is determined in step S407 that the reliability is not equal to or higher than the second reliability threshold value, the process proceeds to step S414. In step S414, the AF control unit 2122 calculates the drive amount of the focus lens 103 and drives the focus lens 103 via the focus lens drive unit 105 so that a highly reliable defocus amount can be obtained. I do. The search drive is a drive in which the drive speed is determined according to the depth of focus without using the calculated defocus amount, and the focus detection process and the focus lens control are performed in parallel.

When the control state of the focus adjustment operation is set in steps S411 to S414, the process proceeds to step S415. In step S415, the camera control unit 212 determines whether or not to end the focus adjustment operation according to the setting of the camera body 20, the input from the camera operation unit 213, and the control state of the focus adjustment operation. If it is determined that the focus adjustment operation is not completed, the process returns to step S402. On the other hand, when it is determined that the focus adjustment operation is finished, this flow is finished. In this way, the camera control unit 212 sets an appropriate detection characteristic according to the control state of the AF operation, the AF mode, and the focus adjustment operation, and performs the focus adjustment operation.

Next, with reference to FIG. 6, the focus detection process (step S404 in FIG. 4) executed by the AF signal processing unit 204 will be described in detail. FIG. 6 is a flowchart showing the focus detection process. Each step of FIG. 6 is mainly executed by the AF signal processing unit 204 based on the command of the camera control unit 212.

First, in step S601, the AF signal processing unit 204 acquires a pair of image signals (image data) as AF signals from a plurality of pixels included in the focus detection region of the image sensor 201. FIG. 7 is an explanatory diagram of a focus detection region 702 on the pixel array 701 of the image sensor 201. The shift regions 703 on both sides of the focus detection region 702 are regions necessary for the correlation calculation. Therefore, the area 704 that combines the focus detection area 702 and the shift area 703 is a pixel area required for the correlation calculation. In FIG. 7, p, q, s, and t are coordinates in the horizontal direction (x-axis direction), respectively, p and q are the x-coordinates of the start point and end point of the area 704 (pixel area), respectively, and s and t are the coordinates. The x-coordinates of the start point and the end point of the focus detection region 702 are shown, respectively.

FIG. 8 is an explanatory diagram of AF signals (a pair of image signals) acquired from a plurality of pixels included in the focus detection region 702 of FIG. 7. In FIG. 8, the solid line 801 is one of the pair of image signals (A image signal), and the broken line 802 is the other of the pair of image signals (B image signal). 8 (a) shows the A image signal and the B image signal before the shift, and FIGS. 8 (b) and 8 (c) show the A image signal and the B image signal in the positive direction from the state of FIG. 8 (a), respectively. It shows a state of shifting in the negative direction.

Subsequently, in step S602 of FIG. 6, the AF signal processing unit 204 relatively shifts the pair of image signals (A image signal, B image signal) acquired in step S601 one pixel (1 bit) at a time. , Calculate the correlation amount (correlation data) of a pair of image signals. The AF signal processing unit 204 describes the A image signal 801 and the B image signal 802 with respect to each of the plurality of pixel lines (scanning lines) provided in the focus detection region, as shown in FIGS. 8 (b) and 8 (c). Shift both of them one bit at a time in the direction of the arrow. Further, the AF signal processing unit 204 calculates the correlation amount of the pair of image signals (A image signal 801 and B image signal 802) for each of the plurality of scanning lines, and adds and averages the correlation amounts of the plurality of scanning lines. Calculate one correlation amount.

In the present embodiment, when calculating the correlation amount, the pair of image signals are configured to be relatively shifted one pixel at a time, but the present embodiment is not limited to this. For example, the pair of image signals may be relatively shifted by two pixels, or may be configured to be shifted in units of more pixels. Further, in the present embodiment, one correlation amount is calculated by adding and averaging the correlation amounts for each of the plurality of scanning lines, but the present embodiment is not limited to this. For example, the addition averaging may be performed on the pair of image signals related to each of the plurality of scanning lines, and then the correlation amount may be calculated on the pair of image signals obtained by the addition averaging.

The correlation amount COR [i] can be calculated using the following equation (1).

In equation (1), i is the shift amount, ps is the maximum shift amount in the minus direction, qt is the maximum shift amount in the plus direction, x is the start coordinate of the focus detection area 702, and y is the focus detection area 702. The end coordinates.

Here, the relationship between the shift amount and the correlation amount COR will be described with reference to FIG. 9 (a) and 9 (b) are explanatory views of the relationship between the shift amount and the correlation amount COR. 9 (b) is an enlarged view of the region 902 of FIG. 9 (a). In FIG. 9A, the horizontal axis represents the shift amount and the vertical axis represents the correlation amount COR. Of the regions 902 and 903 near the extreme values in the correlation amount 901 that changes with the shift amount, the degree of coincidence of the pair of image signals (A image signal, B image signal) is highest in the shift amount corresponding to the smaller correlation amount. ..

Subsequently, in step S603 of FIG. 6, the AF signal processing unit 204 calculates the amount of correlation change based on the amount of correlation calculated in step S602. In the present embodiment, the difference in the correlation amount every other shift in the waveform of the correlation amount 901 shown in FIG. 9A is calculated as the correlation change amount. The amount of correlation change ΔCOR [i] can be calculated using the following equation (2).

Subsequently, in step S604, the AF signal processing unit 204 calculates the amount of image shift using the amount of correlation change calculated in step S603. Here, the relationship between the shift amount and the correlation change amount ΔCOR will be described with reference to FIG. 10 (a) and 10 (b) are explanatory views of the relationship between the shift amount and the correlation change amount ΔCOR. 10 (b) is an enlarged view of the region 1002 of FIG. 10 (a). In FIG. 10A, the horizontal axis represents the shift amount and the vertical axis represents the correlation change amount ΔCOR. The correlation change amount 1001 that changes with the shift amount changes from plus to minus in the regions 1002 and 1003. The state in which the amount of correlation change is 0 is called zero cross, and the degree of coincidence between the pair of image signals (A image signal and B image signal) is the highest. Therefore, the shift amount that gives zero cross is the image shift amount.

In FIG. 10B, 1004 is a part of the correlation change amount 1001. The shift amount (k-1 + α) that gives a zero cross is divided into an integer part β (= k-1) and a fractional part α. The fractional part α can be calculated by using the following equation (3) from the similarity relationship between the triangle ABC and the triangle ADE in FIG. 10 (b).

The integer part β can be calculated from FIG. 10 (b) using the following equation (4).

That is, the image shift amount PRD can be calculated from the sum of the fractional part α and the integer part β. As shown in FIG. 10A, when there are a plurality of zero crosses of the correlation change amount ΔCOR, the one having the larger steepness of the change of the correlation change amount ΔCOR in the vicinity thereof is defined as the first zero cross. This steepness is an index showing the ease of performing AF, and the larger the value, the easier it is to perform high-precision AF. The steepness maxder can be calculated using the following equation (5).

In the present embodiment, when there are a plurality of zero crosses of the correlation change amount, the first zero cross is determined based on the steepness of the zero crosses, and the shift amount that gives the first zero cross is defined as the image shift amount.

Subsequently, in step S605 of FIG. 6, the AF signal processing unit 204 calculates the reliability (correlation reliability) representing the high reliability of the image shift amount calculated in step S604. The reliability of the image shift amount can be defined by the degree of coincidence (degree of coincidence of two images) fnclvl of a pair of image signals (A image signal, B image signal) and the steepness of the above-mentioned correlation change amount ΔCOR. .. The degree of coincidence between the two images is an index showing the accuracy of the amount of image shift, and here, the smaller the value, the better the accuracy. In FIG. 9B, 904 is a part of the correlation amount 901. The degree of coincidence between the two images, fnclvl, can be calculated using the following equation (6).

Finally, in step S606 of FIG. 6, the AF signal processing unit 204 calculates the defocus amount for the target focus detection region using the image shift amount calculated in step S604, and this flow (focus detection). Processing) ends.

According to the present embodiment, the detection characteristics such as the number of focus detection regions to be calculated at the same time and the evaluation band of the AF signal are appropriately set according to the combination of the AF operation, the control state of the focus adjustment operation, and the AF mode. can do. Therefore, according to the present embodiment, it is possible to realize a stable, high-speed and highly accurate focus adjustment operation.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In this embodiment, the setting of the detection characteristics (step S403 in FIG. 4) is different from that in the first embodiment. That is, the camera control unit 212 sets a plurality of focus detection regions, and as the type of focus adjustment operation, depending on the type of focus detection region (whether or not the focus detection region is the main region) for which the detection characteristics are set. And change the detection characteristics. Since other configurations and operations are the same as those in the first embodiment, their description will be omitted.

FIG. 11 is a flowchart showing the setting of the detection characteristic (step S403) in the present embodiment. Each step of FIG. 11 is mainly executed by the camera control unit 212.

First, in step S1101, the camera control unit 212 determines whether or not the focus detection region for which the detection characteristics are set is the main region (primary focus detection region) determined in step S405 of FIG. If it is determined in step S1101 that the focus detection region is the main region, the process proceeds to step S1102. In step S1102, the camera control unit 212 sets the detection characteristics of the high range, the mid range, and the low range (high range + mid range + low range). The high range, mid range, and low range are evaluation bands of the AF signal (signal waveform) used for the correlation calculation, and are as described with reference to FIG.

On the other hand, if it is determined in step S1101 that the focus detection region is not the main region, the process proceeds to step S1103. In step S1103, the camera control unit 212 determines the control state of the focus lens 103 (control state of focus adjustment operation, drive mode). If it is determined in step S1103 that the control state (drive mode) is target drive, the process proceeds to step S1104. In step S1104, the camera control unit 212 sets the detection characteristics of the high region and the mid region (high region + mid region). On the other hand, if it is determined in step S1103 that the control state is defocus drive or search drive, the process proceeds to step S1105. In step S1105, the camera control unit 212 sets the detection characteristics of the mid range and the low range (mid range + low range).

When a plurality of focus detection regions are set, if it is attempted to perform focus detection using all detection characteristics (that is, high-frequency + mid-frequency + low-frequency AF signals) for all focus detection regions, it is predetermined. It is difficult to perform the correlation calculation for all the evaluation bands within the processing time of. On the other hand, if focus detection is performed using AF signals in the high region + mid region or mid region + low region in order to complete the correlation calculation in a predetermined processing time, the focus detection accuracy is lowered or the focus adjustment operation is performed. May take some time. However, as in the present embodiment, the detection characteristics (evaluation band of the AF signal) set in the main region directly connected to the control of the focus adjustment operation are set to high frequency + mid frequency + low frequency to be stable. It is possible to realize a high-speed and highly accurate focus adjustment operation.

According to the present embodiment, the detection characteristics of the AF signal can be appropriately set depending on whether or not the target focus detection region is the main region. Therefore, according to the present embodiment, it is possible to realize a stable, high-speed and highly accurate focus adjustment operation.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. The present embodiment is different from the first embodiment in that the second defocus threshold value is set (changed) according to at least one of the imaging conditions and the state of the AF image signal.

The focus adjustment operation (focus control) in the present embodiment will be described with reference to FIG. FIG. 12 is a flowchart showing the procedure of the focus adjustment operation in the present embodiment. Since FIG. 12 is different from FIG. 4 only in that step S420 is inserted between step S408 and step S409 of FIG. 4, description of steps other than step S420 will be omitted.

If it is determined in step S408 that the reliability is equal to or higher than the first reliability threshold value, the process proceeds to step S420. In step S420, the AF control unit 2122 sets the second defocus threshold. Normally, the second defocus threshold value is determined based on the calculated defocus amount, and the defocus amount can be detected even when the above-mentioned evaluation band is switched to a high region where the detection range of the defocus amount is narrow. It is preferable to set the highest value in the range. However, in the present embodiment, AF is effectively switched between target drive (step S412) and defocus drive (step S413) by setting an appropriate value according to the shooting conditions and the state of the AF image signal. One of the purposes is to achieve both the accuracy and speed of operation. In the present embodiment, as the imaging condition, the amount of image plane movement up to the in-focus state, which is determined according to the focal length and the state of the aperture (aperture diameter), is used. The amount of movement of the image plane until the in-focus state is larger than the predetermined value, and the state of the AF image signal such as the degree of coincidence between the two images, the steepness of the amount of image shift, and the signal level of the two images is good. If, the second defocus threshold is set larger than the normal shooting conditions. At this time, the target shooting conditions may be added as needed, such as brightness and camera shake.

As described above, in the present embodiment, an appropriate second defocus threshold value is set according to the shooting conditions and the state of the AF image signal. This makes it possible to effectively switch between the target drive (step S412) and the defocus drive (step S413) to achieve both the accuracy and speed of the AF operation.

FIG. 13 is an explanatory diagram of the relationship between the reliability and the detected defocus amount in the focus adjustment operation described with reference to FIG. FIG. 13 (a) shows a case where the image plane movement amount (image plane movement amount under a predetermined condition) is normal (first imaging state), and FIG. 13 (b) shows a case where the image plane movement amount is larger than that of FIG. 13 (a). (Second shooting state) are shown respectively. In FIGS. 13A and 13B, the horizontal axis represents reliability, and the value increases as the reliability increases as the focus state approaches. The vertical axis represents the detected defocus amount, and the value decreases as the detected defocus amount approaches the in-focus state.

As described above, the driving state of the focus lens 103 is determined according to the reliability and the detected defocus amount. In general, the state transition is performed in the order of search drive (step S414), defocus drive (step S413), and target drive (step S412) from the greatly blurred upper left state, and finally the lower right is in focus. Focusing is stopped in this state (step S411). In the present embodiment, as described in step S420, when the amount of image plane movement to reach the in-focus state is large depending on the focal length, the state of the aperture, and the like, the second defocus threshold value is increased. As a result, the transition condition from the defocus drive (step S413) to the target drive (step S412) can be relaxed, and the focusing time can be shortened.

As described above, in each embodiment, the control device includes a calculation means (AF signal processing unit 204) and a focus adjustment means (camera control unit 212). The calculation means correspond to the first signal (signal corresponding to the A image signal) and the second signal (corresponding to the B image signal) corresponding to the luminous flux (output signal from the image sensor 201) passing through different pupil regions of the image pickup optical system. The defocus amount is calculated based on the signal). The focus adjusting means performs a focus adjusting operation (focus control) based on the amount of defocus. Further, the focus adjusting means changes the detection characteristics of the first signal and the second signal by the calculation means according to the type of the focus adjusting operation.

Preferably, the detection characteristic includes a characteristic relating to the frequency band (evaluation band) of the first signal and the second signal used by the calculation means to calculate the defocus amount. The evaluation band can be changed by changing the filter (filter band such as high frequency band, mid frequency band, low frequency band, etc.) applied to the first signal and the second signal in the calculation means. More preferably, the focus adjusting means selectively sets one drive mode from a plurality of drive modes (a plurality of control states shown in FIG. 5) for performing the focus adjustment operation as the type of the focus adjustment operation. The plurality of drive modes include a first drive mode (target drive) and a second drive mode (defocus drive or search drive). The first drive mode is a drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped. The second drive mode is a drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while driving the focus lens. The focus adjusting means changes the detection characteristics according to the drive mode. More preferably, the calculation means selects one drive mode from the plurality of drive modes according to the defocus amount (S409 to S414). More preferably, the calculation means calculates the reliability of the first signal and the second signal, and the focus adjusting means selects one drive mode from a plurality of drive modes according to the reliability (S407, S408, S411). ~ S414).

Preferably, as the frequency band, the focus adjusting means makes the first frequency band (high range + mid range) in the first drive mode higher than the second frequency band (mid range + low range) in the second drive mode. To set. Also preferably, the detection characteristics include the number of focus detection regions for detecting the first and second signals (FIG. 5). More preferably, the focus adjusting means sets the number of focus detection regions in the first drive mode to be smaller than the number of focus detection regions in the second drive mode (FIG. 5).

Preferably, the focus adjusting means sets a plurality of focus detection regions for detecting the first signal and the second signal. Then, as the type of the focus adjustment operation, the focus adjustment means has the detection characteristics according to the type of the focus detection area (whether or not the focus detection area is the main area) for which the detection characteristics are set among the plurality of focus detection areas. (S1101 to S1105). More preferably, the focus adjusting means determines the main region from the plurality of focus detection regions, and changes the detection characteristics between the main region and the other region among the plurality of focus detection regions (S1101 to S1105). More preferably, the frequency band as the detection characteristic for the main region is wider than the frequency band for the other regions (S1102, S1104, S1105).

Preferably, the focus adjusting means changes the defocus amount threshold value (second defocus threshold value) for selecting one drive mode (defocus drive) from the plurality of drive modes based on the state of the imaging optical system. do. More preferably, the imaging optical system has a first imaging state (FIG. 13 (a)) and a second imaging state (FIG. 13 (b)) in which the amount of image plane movement under predetermined conditions is larger than that of the first imaging state. Have. Then, the focus adjusting means makes the threshold value of the defocus amount in the second shooting state (second defocus threshold value) larger than the threshold value of the defocus amount in the first shooting state. More preferably, the second shooting state has a longer focal length than the first shooting state. Further, preferably, the aperture diameter is smaller in the second photographing state than in the first photographing state.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

According to each embodiment, it is possible to provide a control device, an image pickup device, a control method, a program, and a storage medium capable of stable, high-speed and highly accurate focus adjustment.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

204 AF signal processing unit (calculation means)
212 Camera control unit (focus adjustment means)

Claims (13)

A calculation means for calculating the defocus amount based on the first signal and the second signal corresponding to the luminous flux passing through different pupil regions of the imaging optical system, and
It has a focus adjusting means that performs a focus adjusting operation based on the defocus amount, and has.
The focus adjusting means selects one drive mode from a plurality of drive modes for performing the focus adjustment operation based on the comparison result of the defocus amount and the threshold value, and depending on the selected drive mode, The characteristics regarding the frequency bands of the first signal and the second signal used by the calculation means to calculate the defocus amount are changed.
The plurality of drive modes are
A first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped.
A second drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while driving the focus lens is included.
The threshold value when the image plane movement amount under a predetermined condition is larger than that in the first imaging state is larger than the threshold value when the imaging optical system is in the first imaging state. Characteristic control device. The control device according to claim 1, wherein the second photographing state has a longer focal length than the first photographing state. The control device according to claim 1, wherein the second photographing state has a smaller aperture diameter than the first photographing state. The calculation means calculates the reliability of the first signal and the second signal, and calculates the reliability.
The control according to any one of claims 1 to 3, wherein the focus adjusting means selects one drive mode from the plurality of drive modes according to the defocus amount and the reliability. Device. The calculation means is characterized in that the reliability is calculated based on the degree of coincidence between the first signal and the second signal and the steepness of the amount of correlation change between the first signal and the second signal. The control device according to claim 4. The focus adjusting means is characterized in that, as the frequency band, the first frequency band in the first drive mode is set to be higher than the second frequency band in the second drive mode. 5. The control device according to any one of 5. Any one of claims 1 to 6, wherein the focus adjusting means changes the number of focus detection regions for detecting the first signal and the second signal according to the selected drive mode. The control device according to the section. The seventh aspect of claim 7, wherein the focus adjusting means is set so that the number of the focus detection regions in the first drive mode is smaller than the number of the focus detection regions in the second drive mode. Control device. An imaging element having a first photoelectric conversion unit and a second photoelectric conversion unit that receive light flux passing through different pupil regions of the imaging optical system, and
A calculation means for calculating the defocus amount based on the first signal and the second signal corresponding to the output signals from the first photoelectric conversion unit and the second photoelectric conversion unit, respectively.
It has a focus adjusting means that performs a focus adjusting operation based on the defocus amount, and has.
The focus adjusting means selects one drive mode from a plurality of drive modes for performing the focus adjustment operation based on the comparison result of the defocus amount and the threshold value, and depending on the selected drive mode, The characteristics regarding the frequency bands of the first signal and the second signal used by the calculation means to calculate the defocus amount are changed.
The plurality of drive modes are
A first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped.
A second drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while driving the focus lens is included.
The threshold value when the image plane movement amount under a predetermined condition is larger than the first imaging state is larger than the threshold value when the imaging optical system is in the first imaging state. An imaging device as a feature. The ninth aspect of the present invention is characterized in that the image pickup element has the first photoelectric conversion unit and the second photoelectric conversion unit for one microlens, and the microlenses are arranged in a two-dimensional manner. The imaging apparatus described. A step of calculating the defocus amount based on the first signal and the second signal corresponding to the luminous flux passing through different pupil regions of the imaging optical system, and
It has a step of performing a focus adjustment operation based on the defocus amount, and
In the step of performing the focus adjustment operation, one drive mode is selected from a plurality of drive modes for performing the focus adjustment operation based on the comparison result of the defocus amount and the threshold value, and the selected drive mode is set. Correspondingly, in the calculation step, the characteristics related to the frequency bands of the first signal and the second signal used for calculating the defocus amount are changed.
The plurality of drive modes are
A first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped.
A second drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while driving the focus lens is included.
The imaging optical system than the threshold value when it is first shooting state, towards the threshold when the image plane movement amount is a second shooting state greater than the first photographing state in a predetermined condition is the size Ikoto A control method characterized by. A step of calculating the defocus amount based on the first signal and the second signal corresponding to the luminous flux passing through different pupil regions of the imaging optical system, and
A program that causes a computer to execute a step of performing a focus adjustment operation based on the defocus amount.
In the step of performing the focus adjustment operation, one drive mode is selected from a plurality of drive modes for performing the focus adjustment operation based on the comparison result of the defocus amount and the threshold value, and the selected drive mode is set. Correspondingly, in the calculation step, the characteristics related to the frequency bands of the first signal and the second signal used for calculating the defocus amount are changed.
The plurality of drive modes are
A first drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while the focus lens of the imaging optical system is stopped.
A second drive mode in which the focus adjustment operation is performed using the first signal and the second signal acquired while driving the focus lens is included.
The imaging optical system than the threshold value when it is first shooting state, towards the threshold when the image plane movement amount is a second shooting state greater than the first photographing state in a predetermined condition is the size Ikoto A program featuring. A storage medium for storing the program according to claim 12.

Images