JP2016142895A - Focusing control device, control method of the same, and control program thereof, as well as imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To implement a stable AF control at any time in a hybrid AF using a contrast AF and phase difference AF.SOLUTION: Under a control of a system control unit 208, an imaging plane phase difference focus detection unit 213 is configured to detect a focusing position of a subject as a first focus position by an imaging plane phase difference AF, and a contrast AF focus detection unit 214 is configured to detect a focusing position of the subject as a second focusing position by a contrast AF. The system control unit is configured to obtain reliability of the first focus position in accordance with a matching level of a pair of images obtained corresponding to the imaging plane phase difference AF; and cause an amount of movement and a movement direction upon moving a focus lens along an optical axis to be changed on the basis of the reliability.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a focus control device, a control method thereof, a control program, and an imaging device, and more particularly to a focus control device that uses contrast AF and phase difference AF for focus detection control.

  In general, contrast AF and phase difference AF are known as focus detection adjustment techniques used in an imaging apparatus. Contrast AF is an AF method that is generally used in imaging devices such as video cameras and digital still cameras. In contrast AF, a high frequency component (hereinafter referred to as a focus evaluation value) of a luminance signal obtained from the image sensor is generated while moving the focus lens along the optical axis. Then, the position of the focus lens where the focus evaluation value is the largest is set as the focus position.

  On the other hand, phase difference AF is an AF method generally used in a single-lens reflex camera. In the phase difference AF, a focus detection unit having a secondary imaging optical system is used. The focus detection unit includes a pupil division unit that divides a light beam that has passed through the exit pupil of the photographing optical system into two regions, and the two divided light beams pass through an optical path division unit arranged in a mirror box, The secondary imaging optical system forms an image on a set of focus detection sensors.

  The amount of deviation of the image signal output according to the amount of light received by the focus detection sensor, that is, the amount of relative positional deviation in the pupil division direction is detected, and thereby the amount of deviation in the focus direction of the photographing optical system is calculated. . Once the accumulation operation is performed by the focus detection sensor, the focus shift amount and the direction of the focus position can be obtained simultaneously, and the focus adjustment operation can be performed at high speed. Then, at the time of photographing after focus detection, the optical path dividing unit is retracted outside the photographing light beam (that is, the optical axis), and the image sensor is exposed to obtain a photographed image.

  Incidentally, in the phase difference AF, in recent years, an imaging surface phase difference AF using an imaging element has been used. In the imaging plane phase difference AF, the pixels of the imaging element are divided into pupils by the microlens (ML), and the light beam is received by a plurality of focus detection pixels to perform imaging and focus detection.

  For example, in one pixel, photodiodes collected by one microlens are divided so that each photodiode receives light from a different pupil plane of the imaging lens. In addition, there is one in which imaging plane phase difference AF is performed by comparing outputs of two photodiodes (see Patent Document 1).

  Further, in some of the light receiving pixels of the image sensor, there is a pixel in which the sensitivity region of the light receiving unit is decentered with respect to the optical axis of the on-chip microlens to provide pupil division (see Patent Document 2). Here, using these pixels as focus detection pixels, focus detection pixels are arranged at predetermined intervals between the imaging pixel groups, and imaging plane phase difference AF is performed. Here, since the location where the focus detection pixels are arranged corresponds to a missing portion of the shooting pixels, when an image is generated, an interpolation process is performed with the surrounding shooting pixels to generate an image.

  By the way, in the imaging plane phase difference AF method, since the phase difference AF is performed on the imaging plane, the above-described contrast AF can be performed together with the imaging plane phase difference AF (hereinafter referred to as hybrid AF). When hybrid AF is used, the advantages of contrast AF and phase difference AF can be utilized.

  For example, when the reliability of the detection result of phase difference AF is high, focusing control is performed based on the amount of deviation detected by phase difference AF. On the other hand, when the reliability is low so that only the focus direction is known for the subject, contrast AF is performed while driving the focus lens in the focus direction of detection in phase difference AF, and AF control is performed at high speed (see Patent Document 3). ).

  Furthermore, if the focus evaluation value of the contrast AF continues to increase when the reliability of the defocus amount detected by the phase difference AF changes from increasing to decreasing while the focus lens is driven in a certain direction. There is one in which the focus lens is continuously driven to suppress false focusing of the phase difference AF (see Patent Document 4).

JP 2001-83407 A JP 2009-3122 A JP2013-37101A JP 2014-202799 A

  However, in the method described in Patent Document 3, when the reliability of the detection result by the phase difference AF is low, the AF operation becomes unstable if the focusing direction obtained as a result of the detection is frequently reversed. Then, the contrast AF operation performed together with the phase difference AF is affected.

  Even in the method described in Patent Document 4, if the focus evaluation value of contrast AF does not continue to increase, the focus direction is reversed when the reliability of the defocus amount detected by phase difference AF changes from increase to decrease. Resulting in. In this case, the AF operation becomes unstable.

  Accordingly, an object of the present invention is to provide a focus control device, a control method thereof, a control program, and an imaging device capable of always stably performing AF control in hybrid AF using contrast AF and phase difference AF. There is to do.

  In order to achieve the above object, a focusing control device according to the present invention drives a focus lens provided in an imaging optical system along an optical axis to perform focusing, and focuses the focus lens on a subject. A focusing control device that detects a focusing position of the subject as a first focusing position by imaging plane phase difference AF; and a focusing position of the subject by contrast AF. A second focus detection unit that detects the second focus position and a degree of coincidence between the pair of images obtained according to the imaging plane phase difference AF, and obtains the reliability of the first focus position. And a control unit that changes a moving amount and a moving direction when the focus lens is moved along the optical axis based on the reliability.

  An image pickup apparatus according to the present invention includes an image pickup element having a photographing pixel that receives light passing through an exit pupil of the image pickup optical system and a focus detection pixel that receives light passing through a partial region of the exit pupil. An imaging unit; and the above-described focusing control device; and a recording unit that records an image obtained by the imaging unit on a recording medium when it is determined to be in focus by the focusing control device. To do.

  A control method according to the present invention is a control method for a focus control device that performs focusing by driving a focus lens provided in an imaging optical system along an optical axis, and focuses the focus lens on a subject. A first focus detection step of detecting the focus position of the subject as a first focus position by imaging surface phase difference AF, and detecting the focus position of the subject as a second focus position by contrast AF. A second focus detection step, a reliability calculation step for obtaining a reliability of the first focus position in accordance with a match degree of a pair of images obtained according to the imaging plane phase difference AF, And a control step of changing a moving amount and a moving direction when the focus lens is moved along the optical axis based on reliability.

  The control program according to the present invention is a control program used in a focus control device that drives a focus lens provided in an imaging optical system along an optical axis to perform focusing, and focuses the focus lens on a subject. In the computer provided in the focus control device, a first focus detection step of detecting the focus position of the subject as a first focus position by imaging plane phase difference AF, and a contrast AF of the subject is detected. A second focus detection step for detecting a focus position as a second focus position, and the first focus position according to the degree of coincidence between a pair of images obtained according to the imaging surface phase difference AF. A reliability calculation step for obtaining a reliability of the control unit, and a control step for changing a movement amount and a movement direction when the focus lens is moved along the optical axis based on the reliability. Characterized in that for the execution.

  According to the present invention, the moving amount and the moving direction of the focus lens are determined based on the reliability of the first in-focus position obtained according to the degree of coincidence of the pair of images obtained according to the imaging surface phase difference AF. change. Thereby, in the hybrid AF using the contrast AF and the phase difference AF, the AF control can always be stably performed.

It is a block diagram which shows the structure about an example of the imaging device with which the focusing control apparatus by embodiment of this invention was used. 3 is a flowchart for explaining a photographing operation of the camera shown in FIG. 1. 3 is a flowchart for explaining a hybrid AF operation shown in FIG. 2.

  Hereinafter, an example of a focusing control device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of an example of an imaging apparatus using a focusing control apparatus according to an embodiment of the present invention.

  The illustrated imaging device is, for example, a digital camera (hereinafter simply referred to as a camera), and includes a camera body 200 and a lens device 100. A lens device (that is, an interchangeable lens) 100 is detachably attached to the camera body 200 by a mount portion (not shown) having an electrical contact unit 106 (that is, replaceable).

  The lens apparatus 100 includes a photographic lens 101, an aperture and shutter 102, and a focus lens 103. The photographic lens 101 includes a zoom mechanism. The light amount of the light image that has passed through the photographing lens 101 is adjusted by the diaphragm and the shutter 102. Then, the optical image is formed on the image sensor 201 provided in the camera body 200 by the focus lens 103.

  The motor 104 drives the focus lens 103 along the optical axis under the control of the lens controller 105. The lens controller 105 controls the lens apparatus 100 and communicates with a system control unit 208 provided in the camera body 200 via a lens communication unit 209 described later.

  The camera body 200 is provided with an image sensor 201 such as a CCD or CMOS image sensor. The image sensor 201 has a photographing pixel that receives light passing through the exit pupil of the imaging optical system and a focus detection pixel that receives light passing through a partial region of the exit pupil. The image sensor 201 outputs an electrical signal (analog signal) corresponding to the optical image. The A / D conversion unit 202 includes a CDS circuit that removes output noise of the image sensor 201 and a non-linear amplifier circuit that performs amplification before the A / D conversion process, and an analog signal that is an output of the image sensor 201 is received. Convert to digital signal.

  The image processing unit 203 performs predetermined image processing on the digital signal output from the A / D conversion unit 202 and outputs image data. The format conversion unit 204 converts the image data into a format such as JPEG, for example, to obtain compressed image data. The format conversion unit 204 temporarily records the compressed image data in a high-speed internal memory (eg, DRAM) 205.

  The DRAM 205 is used as a high-speed buffer, which is a temporary image storage unit, and as a working memory when performing image processing.

  The image recording unit 206 includes, for example, a recording medium such as a memory card and an interface circuit, and the compressed image data recorded in the DRAM 205 is recorded in the image recording unit 206.

  The timing generator 207 sends a timing signal to the A / D conversion unit 202 under the control of the system control unit 208. A system control unit (hereinafter referred to as a CPU) 208 controls the entire camera, and executes shooting processing according to a shooting sequence, for example. Further, the CPU 208 communicates with the lens device 100 through the lens communication unit 209.

  The AE processing unit 210 obtains an optimal exposure value according to the shutter speed or the aperture value under the control of the CPU 208. Image data is temporarily recorded as display image data in the image display memory (VRAM) 211, and image data corresponding to the display image image data is displayed on the image display unit 212.

  In addition to the image, the image display unit 212 displays various information for assisting operations, and also displays the camera state. Further, a distance measurement area is displayed on the image display unit 212 at the time of shooting.

  The imaging surface phase difference focus detection unit 213 performs focus detection by phase difference AF based on an image signal that is an output of a focus detection pixel provided in the image sensor 201 under the control of the CPU 208. For example, the imaging plane phase difference focus detection unit 213 is based on the shift amount of the pair of images formed on the focus detection pixels by the light flux that passes through the pair of exit pupil regions of the imaging optical system (that is, the lens apparatus 100). Imaging surface phase difference AF is performed. Since the imaging plane phase difference AF is described in the above-mentioned Patent Document 2, detailed description thereof is omitted here.

  The contrast AF focus detection unit 214 performs focus detection by contrast AF according to the contrast component of the image information in the image data under the control of the CPU 208. In contrast A, the focus lens 103 is moved to the optical axis, and the position of the focus lens 103 at which the high frequency component (hereinafter referred to as a focus evaluation value) of the luminance signal obtained from the image sensor 210 becomes a peak (maximum). Position).

  The operation unit 215 is operated by a user, and the user gives various instructions to the CPU 208 through the operation unit 215. The operation unit 215 includes, for example, a menu switch for performing various settings such as a camera shooting function and settings for image playback, a switch for switching between the shooting mode and the playback mode, and the like.

  The shooting mode switch (SW) 216 is a switch for selecting a shooting mode such as a macro mode or a sports mode. The main SW 217 is a switch for turning on the camera.

  The standby switch 218 (SW1) is a switch for instructing shooting standby operations such as AF and AE, and the shooting switch 219 (SW2) is a switch operated when shooting after operating SW1.

  FIG. 2 is a flowchart for explaining the photographing operation of the camera shown in FIG. Note that the processing according to the illustrated flowchart is performed under the control of the COU 208.

  When the main SW 217 is turned on and the photographing operation is started, the CPU 208 performs AE processing according to the image data output from the image processing unit 203 by the AE processing unit 211 (step S201). Subsequently, the CPU 208 determines whether or not SW1 is ON (step S202).

  If SW1 is OFF (NO in step S202), CPU 208 returns to the process of step S201. On the other hand, when SW1 is ON (YES in step S202), CPU 208 executes a hybrid AF operation described later (step S203). Here, the exposure conditions (shutter speed, aperture, and sensitivity) in the AF operation are determined by the AE process in step S201 described above.

  Subsequently, the CPU 208 determines whether or not SW1 is ON (step S204). If SW1 is OFF (NO in step S204), CPU 208 returns to the process of step S201. On the other hand, if SW1 is ON (YES in step S204), CPU 208 determines whether SW2 is ON (step S205).

  If SW2 is OFF (NO in step S205), CPU 208 returns to the process in step S204. On the other hand, if SW2 is ON (YES in step S205), CPU 208 controls timing generator 201 and image processing unit 203 to perform shooting, and the obtained image data is recorded on the recording medium by image recording unit 206. (Step S206). Thereafter, the CPU 208 returns to the process of step S201.

  FIG. 3 is a flowchart for explaining the hybrid AF operation shown in FIG.

  When the hybrid AF operation is started, the CPU 208 acquires a focus evaluation value by contrast AF by the contrast AF focus detection unit 214 (step S301). Thereafter, the CPU 208 performs focus detection by the imaging plane phase difference AF by the imaging plane phase difference focus detection unit 213 (step S302). Then, the CPU 208 obtains the reliability of the imaging surface phase difference AF (hereinafter referred to as phase difference reliability) by the imaging surface phase difference focus detection unit 213 (step S303).

  Here, the reliability includes the contrast information regarding the degree of coincidence and contrast of a pair of images obtained as a result of the imaging plane phase difference AF. Note that because of the characteristics of phase difference AF, a high-contrast subject has characteristics that are easier to detect, and therefore contrast information is used here.

  Next, the CPU 208 determines whether or not the reliability (phase difference reliability) of the imaging surface phase difference AF detection result is higher than a preset first reliability threshold value (reliability threshold value 1) (step 1). S304). Here, when the phase difference reliability is higher than the reliability threshold 1, the reliability is set such that the focus lens 103 is driven by the detected defocus amount so that the focus is within the depth of focus with respect to the focus position of the subject. A threshold value 1 is set.

  If the phase difference reliability is higher than reliability threshold value 1 (YES in step S304), CPU 208 determines whether focus lens 103 is being driven (step S305). If the focus lens 103 is being driven (YES in step S305), the CPU 208 controls the motor 104 by the lens controller 105 to stop the focus lens 103 (step S306). Then, the CPU 208 returns to the process of step S301.

  If the focus lens 103 is not being driven (NO in step S305), the CPU 208 determines whether or not the defocus amount detected in step S302 is within the depth of focus (step S307). If the defocus amount is within the depth of focus (YES in step S307), the CPU 208 determines that the focus is in focus, that is, the focus lens 103 is in the focus position (step S308), and performs the hybrid AF operation. finish. Then, the CPU 208 proceeds to the process of step S204 shown in FIG.

  If the defocus amount is not within the depth of focus (NO in step S307), the CPU 208 controls the motor 104 by the lens controller 105, and moves the focus lens 103 along the optical axis by the defocus amount detected in the process of step S302. Are driven (step S309). Then, the CPU 208 returns to the process of step S301.

  In this way, when the reliability of the imaging surface phase difference AF detection result is higher than the reliability threshold 1 by performing the processing of steps S305 to S309, the focus lens 103 is stopped and then detected again. The focus lens 103 can be driven by the defocus amount.

  If the phase difference reliability is equal to or less than the reliability threshold value 1 (less than the first reliability threshold value) (NO in step S304), the CPU 208 determines whether or not the contrast AF focus detection unit 214 has detected the peak focus evaluation value. Is determined (step S310). When the focus evaluation value peak is detected (YES in step S310), the CPU 208 controls the motor 104 by the lens controller 105 to drive the focus lens 103 to a position where the focus evaluation value peak is detected (step S311). ). Then, the CPU 208 determines that focus is achieved (step S312), and ends the hybrid AF operation. Thereafter, the CPU 208 proceeds to the process of step S204 shown in FIG.

  If the focus evaluation value peak is not detected (NO in step S310), CPU 208 determines whether or not the out-of-focus condition is satisfied (step S313). The out-of-focus condition is a condition for determining that there is no subject to be focused. For example, when the driving of the focus lens 103 is completed in the entire movable range of the focus lens 103, that is, when the focus lens 103 detects both the far and near lens ends and returns to the initial position. It is considered as a burning condition.

  If the out-of-focus condition is satisfied (YES in step S313), the CPU 208 determines that it is out of focus (step S314), and ends the hybrid AF operation. Thereafter, the CPU 208 proceeds to the process of step S204 shown in FIG.

  On the other hand, if the out-of-focus condition is not satisfied (NO in step S313), the CPU 208 determines whether or not the focus lens 103 has reached the far end or near end of the driving range (step S315). . When the focus lens 103 reaches the far or near lens end (YES in step S315), the CPU 208 controls the motor 104 by the lens controller 105 to reverse the drive direction of the focus lens 103 (step S316). . Then, the CPU 208 returns to the process of step S301.

  If the focus lens 103 does not reach the far end or near end (NO in step S315), the CPU 208 determines that the phase difference reliability obtained in step S303 is equal to or greater than a predetermined second reliability threshold (reliability). It is determined whether or not the defocus direction is the same as the current drive direction of the focus lens 103 (step S317). Note that, as the reliability threshold 2, if the phase difference reliability is less than the reliability threshold 2, a threshold for determining only the direction of the subject is set.

  If the phase difference reliability is greater than or equal to reliability threshold 2 and the defocus direction is the same as the current drive direction of focus lens 103 (YES in step S317), CPU 208 controls motor 104 by lens controller 105. Then, the focus lens 103 is driven by a predetermined ratio of the defocus amount (step S318). Then, the CPU 208 returns to the process of step S301.

  The predetermined ratio is set so that the driving amount (lens driving amount) of the focus lens 103 is small with respect to the defocus amount (for example, 80%). At this time, the moving speed of the focus lens 103 is set to be equal to or lower than the speed for driving the lens driving amount in one frame. This can prevent the focus lens 103 from exceeding the focus position of the subject when the defocus amount is not correct. Furthermore, the next lens drive can be performed while driving the focus lens 103 without stopping (so-called overlap control).

  If the phase difference reliability is less than the reliability threshold value 2 (less than the second reliability threshold value) or the defocus direction is not the same as the current driving direction of the focus lens 103 (NO in step S317), the CPU 208 The focus lens 103 is driven by a predetermined amount (step S319). Then, the CPU 208 returns to the process of step S301. Here, the predetermined amount is set to be a driving amount suitable for contrast AF (for example, 5 depths).

  Thus, in the embodiment of the present invention, it is determined whether or not to perform contrast AF according to the phase difference reliability of the imaging surface phase difference AF. Further, if the out-of-focus condition is not satisfied during contrast AF, the focus lens is driven again according to the phase difference reliability and the defocus direction. That is, the moving amount and moving direction when the focus lens is moved along the optical axis are changed based on the phase difference reliability. Thus, in the hybrid AF that selectively performs contrast AF and phase difference AF, AF control can be stably performed.

  As is clear from the above description, in the example shown in FIG. 1, the system control unit 208 and the imaging plane phase difference focus detection unit 213 function as the first focus detection unit, and the system control unit 208 and the contrast AF focus detection are performed. The unit 215 functions as a second focus detection unit. The system control unit 208 functions as a reliability calculation unit, and the system control unit 208, the lens controller 105, and the motor 104 function as a control unit.

  Further, the image sensor 201, the A / D conversion unit 202, and the image processing unit 203 function as an imaging unit, and the system control unit 208, the DRAM 208, and the image recording unit 206 function as a recording unit.

  At least the system control unit 208, the imaging plane phase difference focus detection unit 213, the contrast AF focus detection unit 214, the lens controller 105, and the motor 104 constitute a focus control device.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  For example, the function of the above-described embodiment may be used as a control method, and this control method may be executed by the focus control device. Further, a program having the functions of the above-described embodiments may be used as a control program, and the control program may be executed by a computer included in the focusing control device. The control program is recorded on a computer-readable recording medium, for example.

[Other Embodiments]
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 100 Lens apparatus 103 Focus lens 105 Lens controller 201 Image pick-up element 203 Image processing part 208 System control part (CPU)
210 AE processing unit 213 imaging surface phase difference focus detection unit 214 contrast AF focus detection unit 215 operation unit

Claims (13)

A focus control device that drives a focus lens provided in an imaging optical system along an optical axis to perform focusing, and focuses the focus lens on a subject,
First focus detection means for detecting the focus position of the subject as a first focus position by imaging surface phase difference AF;
Second focus detection means for detecting the focus position of the subject as a second focus position by contrast AF;
Reliability calculation means for determining the reliability of the first in-focus position according to the degree of coincidence of a pair of images obtained according to the imaging surface phase difference AF;
Control means for changing a moving amount and a moving direction when moving the focus lens along the optical axis based on the reliability;
A focusing control device characterized by comprising: The first focus detection unit detects the first focus position in accordance with a shift amount of the pair of images,
2. The focus according to claim 1, wherein the second focus detection unit detects a position of the focus lens that maximizes a focus evaluation value indicating the contrast of the subject as a second focus position. Control device.   The said control means stops the said focus lens, if the said focus lens is driven when the said reliability is higher than the preset 1st reliability threshold value. Focus control device.   The control means is in focus when the amount of deviation is within the depth of focus when the focus lens is not driven when the reliability is higher than the first reliability threshold. The focus control device according to claim 3, wherein the focus control device is determined.   When the focus lens is not driven when the reliability is higher than the first reliability threshold, the control unit responds to the shift when the shift is not within the depth of focus. The focus control apparatus according to claim 3, wherein the focus lens is driven.   The control means moves the focus lens to the peak position when the peak position at which the focus evaluation value is maximized is detected when the reliability is equal to or lower than a first reliability threshold set in advance. The in-focus control apparatus according to claim 2, wherein   When the reliability is equal to or lower than a first reliability threshold value that is set in advance, the control unit does not detect a peak position that maximizes the focus evaluation value, and satisfies a predetermined non-focus condition 6. The focus control device according to claim 2, wherein the focus control device determines that the image is out of focus.   8. The control unit according to claim 7, wherein the control unit reverses the drive direction of the focus lens when the focus lens reaches any end of the drive range when the out-of-focus condition is not satisfied. In-focus control device.   If the focusing lens does not reach any end of the driving range when the out-of-focus condition is not satisfied, the control means has a reliability equal to or higher than a predetermined second reliability threshold and the deviation. 9. The focus control apparatus according to claim 8, wherein when the amount direction is the same as the driving direction of the focus lens, the focus lens is driven at a predetermined ratio with respect to the shift amount.   The control means drives the focus lens by a predetermined amount when the reliability is less than a predetermined second reliability threshold or the direction of the shift amount is not the same as the driving direction of the focus lens. The in-focus control apparatus according to claim 9. An imaging means comprising an imaging device having a photographing pixel that receives light passing through an exit pupil of the imaging optical system and a focus detection pixel that receives light passing through a partial region of the exit pupil;
The focusing control device according to any one of claims 1 to 10,
A recording means for recording an image obtained by the imaging means on a recording medium when it is determined to be in focus by the focus control device;
An imaging device comprising: A control method of a focus control device that drives a focus lens provided in an imaging optical system along an optical axis to perform focusing, and focuses the focus lens on a subject,
A first focus detection step of detecting a focus position of the subject as a first focus position by imaging surface phase difference AF;
A second focus detection step of detecting the focus position of the subject as a second focus position by contrast AF;
A reliability calculation step of determining the reliability of the first in-focus position according to the degree of coincidence of a pair of images obtained according to the imaging surface phase difference AF;
A control step of changing a moving amount and a moving direction when moving the focus lens along the optical axis based on the reliability;
A control method characterized by comprising: A control program used in a focus control device that drives a focus lens provided in an imaging optical system along an optical axis to perform focusing, and focuses the focus lens on a subject,
In the computer provided in the focusing control device,
A first focus detection step of detecting a focus position of the subject as a first focus position by imaging surface phase difference AF;
A second focus detection step of detecting the focus position of the subject as a second focus position by contrast AF;
A reliability calculation step of determining the reliability of the first in-focus position according to the degree of coincidence of a pair of images obtained according to the imaging surface phase difference AF;
A control step of changing a moving amount and a moving direction when moving the focus lens along the optical axis based on the reliability;
A control program characterized by causing

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