JP6521649B2 - Image pickup apparatus, control method thereof and program - Google Patents

Description

  The present invention relates to an improvement in focus detection technology in an imaging device such as a digital camera or digital video camera.

  In an imaging apparatus such as a digital camera, as a method of driving a focus lens in the optical axis direction to focus on an object, an AF (automatic focusing operation) is performed using an image signal obtained from an imaging element such as a CCD sensor. The auto focus method is used. In this AF method, for example, while moving the focus lens in the optical axis direction, a focus evaluation value indicating the contrast in the focus detection area set in advance is sampled, and the position where the focus evaluation value becomes maximum is set as the in-focus position. Perform focus control.

  In this focusing control, when the setting of the aperture is on the open side, the depth of focus becomes shallow, so the peak shape of the focus evaluation value becomes a sharp mountain-shaped curve as shown in FIG. 10A. On the other hand, when the aperture setting is on the small aperture side, the depth of focus becomes deep, so the peak shape of the focus evaluation value becomes a gentle mountain-shaped curve as shown in FIG. 10 (b). Therefore, if the focus evaluation value is sampled at the same interval regardless of the aperture setting, the focusing accuracy decreases on the open side, and the peak position of the focus evaluation value becomes difficult to determine on the small stop side. It will

  In order to solve such a problem, there has been proposed a technique of changing the amount of lens drive in accordance with the aperture setting (Japanese Patent Application Laid-Open No. 2001-147118). However, in this proposal, as shown in FIG. 11, when the peak position of the focus evaluation value is located near the lens end, such as an infinite distance object or a close object, one side of the peak of the focus evaluation value is limited. . For this reason, in particular, on the small stop side shown in FIG. 11B, it is difficult to determine the peak shape of the focus evaluation value.

  Therefore, a technique has been proposed in which the movable range of the focus lens is widely set in accordance with the state of the aperture (Japanese Patent Application Laid-Open No. 2008-112118).

JP, 2000-292683, A JP, 2008-046224, A

  However, in recent years, when the movable range of the focus lens can not be expanded due to the restriction due to the miniaturization of the imaging device, the technology of Patent Document 2 can not be applied. For this reason, as in Patent Document 1, when the peak position of the focus evaluation value is located near the lens end, such as an infinite distance object or a close object, one side of the peak of the focus evaluation value is limited. At the stop side, it is difficult to determine the peak shape of the focus evaluation value.

  Therefore, an object of the present invention is to provide a technology capable of realizing high accuracy in focusing accuracy of an object in a small aperture state even in an imaging apparatus in which the movable range of a focus lens is limited. Do.

In order to achieve the above object, an image pickup apparatus according to the present invention comprises an acquisition means for acquiring a focus evaluation value based on an output signal from an image pickup device, and a control means for controlling the drive of a diaphragm and the movement of a focus lens. wherein the control means, wherein when the focus lens has reached one of the ends of the movable range, and whether squeezing the diaphragm than the predetermined aperture value, the focal point evaluation value in the vicinity of the lens edge that the arrival Whether or not the focus evaluation value continues to increase toward the lens end of the focus lens according to the acquisition result of at least one of whether or not the local maximum value of the focus evaluation value is detected. It is determined that the focus evaluation value continues to increase while the aperture is narrowed more than a predetermined aperture value, or it is determined that the maximum value of the focus evaluation value is detected. To the slower than the moving speed before reversing the movement speed of the focus lens during acquisition of the focus evaluation value after reversing the moving direction of the focus lens, the increase in the focus evaluation value has continued, Alternatively, even if it is determined that the local maximum value of the focus evaluation value is detected, the focus evaluation after reversing the moving direction of the focus lens if the diaphragm is not narrowed more than a predetermined diaphragm value The moving speed of the focus lens at the time of acquiring a value is not changed .

  According to the present invention, even in the case of an imaging apparatus in which the movable range of the focus lens is limited, it is possible to realize high accuracy of focusing accuracy of the subject in the small aperture state.

FIG. 1 is a block diagram showing a system configuration of a digital camera which is an example of an embodiment of an imaging device of the present invention. It is a flowchart figure explaining the imaging | photography operation in the digital camera shown in FIG. FIG. 5 is a flowchart for explaining the details of an AF operation in step S203 of FIG. 2; It is a flowchart figure explaining the detail of the focus evaluation value peak determination processing of FIG.3 S307. It is a graph which shows the relationship between the position of a focus lens, and a focus evaluation value. It is a flowchart figure explaining the detail of the small aperture focusing determination process in FIG.3 S313. FIG. 5 is a flowchart for explaining the details of the near-end peak determination process in step S317 in FIG. 3. It is a flowchart figure explaining the detail of the focus evaluation value memory | storage process in FIG.3 S319. It is a flowchart figure explaining the detail of the lens speed setting process in FIG.3 S320. It is a graph explaining the influence which an aperture state gives to the peak shape of a focus evaluation value. FIG. 7 is a graph for explaining the focus evaluation value peak when the in-focus position of the subject is at the end of the focus lens.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a system configuration of a digital camera which is an example of an embodiment of an imaging apparatus of the present invention.

  In the digital camera of the present embodiment, as shown in FIG. 1, the subject light flux that has passed through the photographing lens 101, the aperture / shutter 102 and the focus lens 104 forms an image on the imaging surface of the imaging device 107 and is photoelectrically converted. The imaging element 107 is configured of a CCD sensor, a CMOS sensor, or the like, and outputs an analog image signal obtained by photoelectric conversion to the A / D conversion unit 108. The A / D conversion unit 108 converts an analog image signal output from the image sensor 107 into a digital image signal, and further includes a CDS circuit and a non-linear amplifier circuit for removing output noise of the image sensor 107.

  The digital image signal output from the A / D conversion unit 108 is output to the image processing unit 109 and subjected to predetermined image processing. The image data after image processing is recorded in the image recording unit 112 via the format conversion unit 110 and the DRAM 111, and displayed on the image display unit 115 via the format conversion unit 110, the DRAM 111 and the VRAM 114.

  The image recording unit 112 includes a recording medium such as a memory card and an interface thereof. The DRAM 111 is used as a high-speed buffer as a temporary image storage unit, or as a working memory in image compression / decompression. The image display unit 115 displays a photographing screen and a distance measurement area at the time of photographing in addition to the display of an image, the display for operation assistance and the display of a camera state.

  The system control unit 113 controls the entire camera such as a photographing sequence. The AE processing unit 103 is connected to the image processing unit 109 and the aperture / shutter 102, and controls the drive of the aperture / shutter 102. The AF processing unit 106 controls focusing by driving the focus lens 104 in the optical axis direction via the motor 105.

  The operation unit 116 includes a release button operated by the user, a power button, a zoom lever, a mode switching dial, and the like. The shooting mode switch 117 is a switch for selecting a shooting mode such as a macro mode, a distant view mode, or a sport mode, and changes a distance measurement distance range, an AF operation and the like according to a shooting mode selected by the user.

  The power switch 118 is a switch that is turned on to power on the system when the power button is operated. A release switch (SW1) 119 is a switch that is turned on by half-pressing operation of the release button or the like to perform shooting preparation operations such as AF and AE. The release switch (SW2) 120 is a switch for turning on by full-press operation of the release button or the like to perform a photographing operation.

  Next, the photographing operation of the digital camera shown in FIG. 1 will be described with reference to FIGS. Each process in FIG. 2 is executed by the CPU or the like of the system control unit 113 according to a program stored in a storage unit (not shown).

  In FIG. 2, in step S201, the system control unit 113 causes the AE processing unit 103 to perform AE processing based on the output of the image processing unit 109, and the process proceeds to step S202. In step S202, the system control unit 113 proceeds to step S203 if the release switch (SW1) 119 is on, and returns to step S201 if the release switch (SW1) 119 is not on.

  In step S203, the system control unit 113 performs an AF operation, and proceeds to step S204. Here, the exposure conditions (shutter speed, aperture, sensitivity) during the AF operation are determined by the AE processing in step S201. The details of the AF operation here will be described later with reference to FIGS. 3 to 9.

  In step S204, the system control unit 113 proceeds to step S205 if the release switch (SW1) 119 is on, and returns to step S201 if the release switch (SW1) 119 is not on. In step S205, the system control unit 113 proceeds to step S206 if the release switch (SW2) 120 is on, and returns to step S204 if the release switch (SW2) 120 is not on. In step S206, the system control unit 113 performs a photographing operation, and returns to step S201.

  FIG. 3 is a flow chart for explaining the details of the AF operation in step S203 of FIG.

  In FIG. 3, in step S301, the system control unit 113 sets a focus detection area in the imaging surface, and the process proceeds to step S302. In step S302, the system control unit 113 initializes a far-end peak evaluation value described later to 0, and proceeds to step S303. In step S303, the system control unit 113 initializes a far-end peak position described later, and proceeds to step S304. The value to be initialized here is, for example, 0.

  In step S304, the system control unit 113 initializes a low speed scan Cnt to be described later to 0, and the process proceeds to step S305. In step S305, the system control unit 113 acquires the current position of the focus lens 104, and proceeds to step S306. In step S306, the system control unit 113 acquires a focus evaluation value indicating the contrast of the focus detection area set in advance on the imaging surface, and proceeds to step S307.

  In step S307, the system control unit 113 performs focus evaluation value peak determination, and proceeds to step S308.

  Here, the details of the focus evaluation value peak determination process in step S307 will be described with reference to FIGS. 4 and 5.

  FIG. 4 is a flowchart for explaining the details of the focus evaluation value peak determination process of step S307 in FIG. FIG. 5 is a graph showing the relationship between the position of the focus lens 104 and the focus evaluation value.

  In FIG. 4, in step S401, the system control unit 113 determines whether or not the local maximum value of the sampled focus evaluation value has been detected. If detected, the process proceeds to step S402. If not detected, the system control unit 113 proceeds to step S408. move on. In the detection of the local maximum here, as shown in FIG. 5, when the focus evaluation value increases and then decreases, it is determined that the local maximum is detected.

  In step S402, the system control unit 113 determines whether or not IncCnt is greater than or equal to IncCntThr set in advance. If it is greater than or equal to IncCntThr, the process proceeds to step S403. Here, IncCnt is the number of times the focus evaluation value is continuously increased up to the focus lens position of the maximum value of the focus evaluation value detected in step S401. In FIG. 5, IncCnt = 3.

  In step S403, the system control unit 113 determines whether or not DecCnt is greater than or equal to the preset DecCntThr. If it is greater than or equal to DecCntThr, the process advances to step S404; Here, DecCnt is the number of times the focus evaluation value continuously decreases from the focus lens position of the maximum value of the focus evaluation value detected in step S401 to the current focus lens position. In FIG. 5, DecCnt = 2 .

  In step S404, the system control unit 113 determines whether or not MaxMinEvaF is equal to or greater than MaxMinEvaFThr set in advance. Then, if MaxMinEvaF is equal to or larger than MaxMinEvaFThr, the system control unit 113 proceeds to step S405, and if smaller than MaxMinEvaFThr, the system control unit 113 proceeds to step S408. As shown in FIG. 5, MaxMinEvaF here is a focus evaluation value between the focus lens position of the maximum value of the focus evaluation value detected in step S402 and a predetermined sampling number after exceeding the maximum value of the focus evaluation value. The difference between the maximum value and the minimum value of

  In step S405, the system control unit 113 determines whether or not MaxMinEvaB is equal to or greater than MaxMinEvaBThr set in advance. Then, the system control unit 113 proceeds to step S406 if MaxMinEvaB is equal to or greater than MaxMinEvaBThr, and proceeds to step S408 if less than MaxMinEvaBThr. MaxMinEvaB here is, as shown in FIG. 5, the maximum focus evaluation value between a predetermined sampling number before the focus lens position of the maximum value of the focus evaluation value and the lens position of the maximum value of the focus evaluation value. It is the difference from the minimum value.

  In step S406, the system control unit 113 determines whether MaxMinEva is equal to or greater than MaxMinEvaThr set in advance. Then, if MaxMinEva is equal to or greater than MaxMinEvaThr, the system control unit 113 proceeds to step S407, and if less than MaxMinEvaThr, the system control unit 113 proceeds to step S408. MaxMinEva here is the difference between the maximum value and the minimum value among all the focus evaluation values sampled, as shown in FIG.

  In step S407, the system control unit 113 determines that the focus evaluation value peak detection result is OK, and ends the processing. In step S408, the system control unit 113 determines that the focus evaluation value peak detection result is NG. It judges and ends processing. In this manner, in-focus determination is performed to determine the in-focus position of the subject based on the peak shape of the focus evaluation value, and the peak detection result is determined.

  Returning to FIG. 3, in step S308, if the focus evaluation value peak detection result is OK in the focus evaluation value peak determination in step S307, the system control unit 113 proceeds to step S309 and the focus evaluation value peak detection result If no, the process proceeds to step S312. In step S309, the system control unit 113 stops the driving of the focus lens 104, and proceeds to step S310.

  In step S310, the system control unit 113 moves the focus lens 104 to the focus evaluation value peak position, and proceeds to step S311. Here, the focus evaluation value peak position is obtained using, for example, a focus evaluation value sampled near the focus lens position at which the focus evaluation value sampled in the focus evaluation value peak determination in step S307 has a maximum value. Specifically, the focus lens position at which the focus evaluation value becomes maximum is determined by interpolation calculation using the focus evaluation value and the corresponding focus lens position. In step S311, the system control unit 113 ends the processing on the assumption that the result of the AF operation is in focus.

  On the other hand, in step S312, the system control unit 113 determines whether or not the out-of-focus condition is satisfied. If the condition is satisfied, the process proceeds to step S313. If the condition is not satisfied, the process proceeds to step S316. Here, the out-of-focus condition is a condition for determining that the subject in-focus position is not found within the movable range of the focus lens 104. For example, both ends of the movable range of the focus lens 104 are detected to start AF operation. It is determined that the focus lens 104 has returned to the position. In step S313, the system control unit 113 performs small aperture focusing determination, and the process proceeds to step S314.

  Here, the details of the small aperture focusing determination process in step S313 will be described with reference to FIG. FIG. 6 is a flow chart for explaining the details of the small aperture focusing determination process in step S313 in FIG.

  In FIG. 6, in step S601, the system control unit 113 determines whether a far-end peak flag described later is TRUE. If TRUE, the process proceeds to step S602, and if not TRUE, the process proceeds to step S604. In step S602, the system control unit 113 sets the peak position for moving the focus lens 104 in step S310 in FIG. 3 as the far-end peak lens position described later, and the process proceeds to step S603. In step S603, the system control unit 113 determines that the small aperture is in focus and ends the process. In step S604, the system control unit 113 determines that the small aperture is not in focus and ends the process.

  As a result, even if the AF scanning is performed in the entire movable range of the focus lens 104 at the time of the small aperture and the focus evaluation value peak determination result is not OK in step S307 of FIG. Can be focused on that position.

  Returning to FIG. 3, in step S314, the system control unit 113 determines whether or not the small aperture focusing is determined in the small aperture focusing determination in step S313, and the small aperture focusing is determined. If so, the process proceeds to step S309; otherwise, the process proceeds to step S315. In step S315, the system control unit 113 ends the processing as the result of the AF operation is out of focus.

  In step S316, the system control unit 113 performs lens end determination to determine whether or not the focus lens 104 has reached any of the two ends of the movable range. If it has reached, the process proceeds to step S317 and has not reached In the case, the process proceeds to step S319. In step S317, the system control unit 113 performs peak determination processing near the end, and the process proceeds to step S318.

  Here, the details of the near-end peak determination processing in step S317 will be described with reference to FIG. FIG. 7 is a flowchart for explaining the details of the near-end peak determination process in step S317 in FIG.

  In FIG. 7, in step S701, the system control unit 113 determines whether the current aperture state is smaller than a predetermined aperture value set in advance. If the aperture state is smaller, the process proceeds to step S702. If not, end the process. Here, the predetermined aperture value set in advance is, for example, an aperture value at which it is difficult to detect the focus evaluation value peak when the subject in-focus position is located near the lens end.

  In step S702, the system control unit 113 determines whether or not the focus evaluation value has continuously increased a predetermined number of times or more including the currently acquired focus evaluation value. If the focus evaluation value has increased, the process proceeds to step S704. Proceed, otherwise proceed to step S703. In step S703, the system control unit 113 determines whether or not the local maximum value of the focus evaluation value has been detected near the end of the focus lens. If it has been detected, the process proceeds to step S704, otherwise the process ends. .

  In step S704, the system control unit 113 sets the low speed flag to TRUE, and the process proceeds to step S705. Here, the low speed flag is used to determine whether to slow down the drive speed of the focus lens so that the focus evaluation value peak position can be detected even if the focus evaluation value peak shape becomes a gentle curve at small aperture near the lens end. Is the flag of In step S705, the system control unit 113 performs an infinite distance side lens end determination process to determine whether the lens end that has reached the lens end is an infinite distance side lens end. Proceed, otherwise terminate the process.

  In step S706, the system control unit 113 sets the far-end peak flag to TRUE, and ends the process. Here, the far-end peak flag is a flag for performing in-focus position determination that determines that the subject in-focus position is present near the end of the focusing lens on the infinity side. This flag is for focusing on the subject near the lens end if the focus evaluation value peak judgment result in step S307 in FIG. 3 does not become OK even if AF scanning is performed in the entire movable range of the focus lens at the time of small aperture. Used for focusing control.

  Returning to FIG. 3, in step S318, the system control unit 113 reverses the moving direction of the focus lens 104, and returns to step S305. In step S319, the system control unit 113 performs focus evaluation value storage processing, and proceeds to step S320.

  Here, the details of the focus evaluation value storage process in step S319 will be described with reference to FIG. FIG. 8 is a flowchart for explaining the details of the focus evaluation value storage process in step S319 in FIG.

  In FIG. 8, in step S801, the system control unit 113 determines whether the low speed flag is TRUE. If it is TRUE, the process proceeds to step S802, and if it is not TRUE, the process proceeds to step S807. In step S802, the slow scan Cnt is incremented, and the process proceeds to step S803. Here, the slow scan Cnt indicates the number of times the focus evaluation value is sampled in a state in which the drive speed of the focus lens 104 is slowed, and is used to slow the drive speed of the focus lens 104 only near the lens end.

  In step S803, the system control unit 113 determines whether the far-end peak flag is TRUE. If TRUE, the process proceeds to step S804. If not, the process proceeds to step S807. In step S804, the system control unit 113 determines whether the current focus evaluation value is equal to or higher than the far-end peak evaluation value stored in the storage unit. If the current focus evaluation value is equal to or higher than the far-end peak evaluation value, the process proceeds to step S805. If it is less than the far-end peak evaluation value, the process proceeds to step S 807.

  The far-end peak evaluation value here indicates the maximum value of the focus evaluation value while slowing the moving speed of the focus lens 104 near the lens end at the time of the small aperture, and the position of the focus lens 104 at that time is also The far-end peak lens position is stored in the storage means. This far-end peak evaluation value is near the lens end when the focus evaluation value peak determination result in step S307 in FIG. 3 is not OK even if AF scanning is performed in the entire movable range of the focus lens 104 at the small aperture. It is used to control focusing on the subject's in-focus position.

  In step S805, the system control unit 113 proceeds to step S806 with the far-end peak evaluation value as the current focus evaluation value. In step S806, the system control unit 113 sets the far-end peak lens position in step S602 as the lens position acquired this time, and proceeds to step S807.

  In step S 807, the system control unit 113 determines whether the low speed flag is TRUE and the low scan Cnt is equal to or more than a predetermined value. Then, if the low speed flag is TRUE and the low scan Cnt is equal to or more than the predetermined value, the system control unit 113 proceeds to step S808, otherwise ends the processing.

  In step S808, the system control unit 113 sets the low speed flag to FALSE and proceeds to step S809. In step S809, the system control unit 113 sets the low speed scan Cnt to 0 and ends the process.

  Returning to FIG. 3, in step S320, the system control unit 113 performs lens speed setting, and the process proceeds to step S321.

  Here, the details of the lens speed setting process in step S320 will be described with reference to FIG. FIG. 9 is a flow chart for explaining the details of the lens speed setting process in step S320 in FIG.

  In FIG. 9, in step S901, the system control unit 113 determines whether the low speed flag is TRUE or not. If it is TRUE, the process proceeds to step S902, and if it is not TRUE, the process proceeds to step S903. If the low speed flag is TRUE, the moving direction of the focus lens 104 is reversed in the processing of step S317 and step S318. In step S902, the system control unit 113 sets the moving speed of the focus lens 104 to a predetermined sampling number of the focus evaluation value or a predetermined moving range of the focus lens 104 at a speed lower than the normal speed before inversion and ends the processing. . In step S 903, the system control unit 113 sets the moving speed of the focus lens 104 to the normal speed, and ends the processing.

  In this way, when the subject focusing position exists near the lens end at the time of the small aperture, the moving speed of the focus lens 104 is reduced only near the lens end to prevent the AF time thereafter from becoming long. be able to.

  Returning to FIG. 3, in step S321, the system control unit 113 moves the focus lens 104 at the lens speed set in step S320, and returns to step S305. A series of processes from step S305 to step S318 or step S305 to step S321 is performed in one frame worth of the current frame rate.

  As described above, in the present embodiment, even in a relatively small digital camera in which the movable range of the focus lens 104 is limited, high precision of the focusing accuracy of the subject in the small aperture state is realized. Can.

  The present invention is not limited to the ones exemplified in the above embodiments, and can be appropriately modified without departing from the scope of the present invention.

  For example, in the low speed control in step S902 in FIG. 9, the predetermined sampling number or the predetermined lens movement range may be changed according to the diaphragm stop value of the diaphragm or the movable range of the focus lens 104. Further, the moving speed of the focus lens 104 may be changed according to the movable range of the focus lens 104.

  The present invention is also realized by executing the following processing. That is, software (program) for realizing the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU or the like) of the system or apparatus reads the program. It is a process to execute. It can also be realized by executing software (program) acquired via a network or various storage media on a personal computer (CPU, processor).

101 Shooting lens 102 Aperture / shutter 103 AE processing unit 104 Focus lens 105 Motor 106 AF processing unit 112 Image recording unit 113 System control unit

Claims (9)

Acquisition means for acquiring a focus evaluation value based on an output signal from the imaging device;
Control means for controlling the drive of the aperture and the movement of the focus lens;
The control means
If the focus lens has reached one of the ends of the movable range, and whether the aperture is narrowed than the predetermined aperture value, the in response to the acquisition result of the focus evaluation value in the vicinity of the lens edge that the arrival It is determined whether or not the focus evaluation value continues to increase toward the lens end of the focus lens, and / or whether a maximum value of the focus evaluation value is detected.
When it is determined that the focus evaluation value continues to increase while the stop is narrowed more than a predetermined stop value, or it is determined that the maximum value of the focus evaluation value is detected , the moving direction of the focus lens is Making the moving speed of the focus lens at the time of obtaining the focus evaluation value after inversion slower than the moving speed before inversion;
Even if it is determined that the focus evaluation value continues to increase or the local maximum value of the focus evaluation value is detected, the focus lens is not narrowed more than the predetermined aperture value. An imaging apparatus characterized by not changing the moving speed of the focus lens at the time of acquiring the focus evaluation value after reversing the moving direction of the image pickup apparatus. The control means
A focus evaluation value is acquired by sampling an output signal of the image pickup element in movement control of a focus lens.
The image pickup apparatus according to claim 1, The control means
The predetermined aperture value is a value predetermined as an aperture value that makes it difficult to detect the peak of the focus evaluation value when the position where the subject is in focus is located near the lens end.
The imaging device according to claim 1 or 2, characterized in that:   When the control means makes the moving speed of the focus lens after reversing the moving direction of the focus lens slower than the moving speed before reversing, the predetermined sampling number of the focus evaluation value or the predetermined value of the focus lens The imaging apparatus according to claim 3, wherein the moving speed of the focus lens is reduced in a moving range of   The predetermined sampling number of the focus evaluation value or the predetermined moving range of the focus lens is changed according to at least one of the state of the diaphragm or the movable range of the focus lens. The imaging device of description.   The imaging apparatus according to claim 4, wherein a moving speed of the focus lens is changed according to a movable range of the focus lens. The apparatus further comprises storage means for storing the maximum value of the focus evaluation value near the lens end and the position of the focus lens corresponding to the maximum value after the moving direction of the focus lens is inverted,
When the peak of the focus evaluation value does not exist after reversing the moving direction of the focus lens, the control means sets the position of the focus lens stored by the storage means as the in-focus position. The imaging apparatus according to any one of claims 1 to 6, wherein movement is controlled. An acquisition step of acquiring a focus evaluation value based on an output signal from the imaging element;
Control step of controlling the movement of the diaphragm drive and the focus lens,
In the control step:
If the focus lens has reached one of the ends of the movable range, and whether the aperture is narrowed than the predetermined aperture value, the in response to the acquisition result of the focus evaluation value in the vicinity of the lens edge that the arrival It is determined whether or not the focus evaluation value continues to increase toward the lens end of the focus lens, and / or whether a maximum value of the focus evaluation value is detected.
When it is determined that the focus evaluation value continues to increase while the stop is narrowed more than a predetermined stop value, or it is determined that the maximum value of the focus evaluation value is detected , the moving direction of the focus lens is Making the moving speed of the focus lens at the time of obtaining the focus evaluation value after inversion slower than the moving speed before inversion;
Even if it is determined that the focus evaluation value continues to increase or the local maximum value of the focus evaluation value is detected, the focus lens is not narrowed down to a predetermined aperture value. A control method of an image pickup apparatus, wherein a moving speed of the focus lens at the time of obtaining the focus evaluation value after reversing a moving direction of the lens is not changed .   A program that causes a computer to execute the steps of the control method of an imaging apparatus according to claim 8.

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