JP6508953B2 - Imaging device, control method of imaging device, and program - Google Patents

Description

  The present invention relates to an improvement in focus detection technology in an imaging apparatus such as a single-lens reflex camera.

  In an imaging apparatus such as a digital single-lens reflex camera, various proposals have been made in order to improve the focusing accuracy in AF (Auto Focus) (Japanese Patent Application Laid-Open No. 2003-101501).

  For example, when calculating the movement amount or movement speed of the focus lens, the correction information regarding the deformation amount of the power transmission mechanism generated at the time of lens drive is added to the pulse conversion movement amount of the focus lens detected by an encoder or the like. Techniques have been proposed to improve accuracy. In this proposal, it is possible to take into consideration factors of deformation of the power transmission mechanism that occur when the actuator is driven at high speed, and factors of change of torque required to drive the focus lens that occur due to posture change of the camera. Therefore, it becomes possible to calculate the actual position information and velocity information of the focus lens more accurately.

  However, the error factor for calculating the position information of the focus lens more accurately is not necessarily due to only the amount of deformation of the power transmission mechanism.

  A lens interchangeable digital single-lens reflex camera can use various interchangeable lenses attached to the camera body by performing communication (lens communication) with each other according to a common communication protocol. In addition, since there are a wide variety of interchangeable lenses, there are also some variations in the type of an actuator that drives the focus lens and the detection system that detects the amount of drive of the actuator.

  The camera body grasps the position of the focus lens by acquiring the pulse conversion movement amount of the focus lens from the interchangeable lens. Therefore, on the camera body side, it is not possible to grasp the position of the focus lens with accuracy higher than the resolution of the pulse conversion movement amount of the focus lens defined by the communication protocol between the camera body and the interchangeable lens. Also, based on detection information on the interchangeable lens side, when the current focus lens position is an intermediate position α (see FIG. 10A) less than the resolution of pulse conversion movement (FPC), how is the pulse conversion movement The camera body can not know whether the process to be determined is being performed. This is because the process of determining the pulse conversion movement amount is performed on the interchangeable lens side.

  Therefore, when it is necessary for the camera body to take into account the accuracy more than the resolution of the pulse conversion movement amount of the focus lens in order to improve the focusing accuracy of AF, an error factor depending on the detection method of position information by the actuator and detection system Can not be ignored.

  Next, a representative example of a method of detecting positional information of an actuator that drives a focus lens and the focus lens will be described.

(A) Example of DC motor (low resolution detection method)
When a DC motor is used as an actuator for driving the focus lens, it is necessary to use an encoder for detecting the position and speed of the focus lens. Specifically, a pulse plate having slits formed at equal intervals in the circumferential direction is fixed to one gear of the reduction mechanism, and the light emitting unit and the light receiving unit of the photo interrupter are disposed to sandwich the pulse plate. . The photo interrupter electrically detects the passage of light at the slit by the pulse plate and the interruption of the light, and outputs a pulse signal.

  Since the pulse signal indicating the movement amount of the actuator has a correlation with the position of the focus lens, it can be used as position information when performing focus adjustment as a pulse conversion movement amount of the focus lens.

  However, when counting pulse signals using a photo interrupter, an error occurs as follows. That is, as shown in FIG. 10B, when the position of the focus lens at the time of driving refers to the interchangeable lens from the camera body side at the intermediate position whose resolution is lower than the resolution assumed for the converted pulse amount, It is not possible to detect detailed position information higher than the switching resolution of the signal. Therefore, a count error of about 0 to 1 pulse may occur with respect to the actual lens position.

  Further, as a feature of this detection method, the pulse conversion movement amount of the focus lens is counted at the switching edge of the pulse signal. For this reason, when the amount of pulse conversion movement is inquired from the camera body to the interchangeable lens side at timing α in FIG. 10B, 3 for driving to the left of the figure, 2 for driving to the right, and so on. A shift of one pulse tends to occur depending on the drive direction of the focus lens. And this shift may occur even while the actuator is in operation and at rest.

(B) Example of stepping motor (STM) (high resolution detection method)
When a stepping motor is used as an actuator for driving the focus lens, the stepping motor is a point that operates in synchronization with a pulse signal supplied to the motor, and rotates by one step per one electric signal pulse. In addition, the stepping motor may change the amount of rotation for one step by changing the way of supplying current to the winding, such as one-phase excitation, two-phase excitation, one-two phase excitation, and micro step drive it can. The stepping motor does not need to prepare a position detection mechanism separately as the DC motor described above, and the supplied pulse has a correlation with the position of the focus lens, so when performing focus adjustment as the pulse conversion movement amount of the focus lens. It can be used as position information.

  However, the resolution of the pulse conversion movement amount of the focus lens that can be acquired from the interchangeable lens side by the camera body does not necessarily coincide with one step of the stepping motor. For example, in order to realize smoother drive control of a motor, a micro step drive method is adopted, an actual stop position is made into a 1-2 phase position (one eighth) unit, and the pulse conversion movement amount of the focus lens is 1 It is conceivable to supply the -2 phase position (Fig. 10 (c)).

  In this case, on the interchangeable lens side, the position is grasped with a resolution higher than the 1-2 phase position (1/8) unit, but when the focus lens is in a driving state, the resolution of pulse conversion movement amount of the focus lens There is a state in which the focus lens exists at the above position. On the other hand, when stopping the focus lens, control is always performed so as to stop at a position that matches the resolution of the pulse conversion movement amount of the focus lens. Therefore, when the focus lens is in a driving state, how the interchangeable lens side returns the pulse conversion movement amount of the focus lens to the camera body side at this intermediate position depends on the internal processing of the interchangeable lens.

  For example, as shown in FIG. 10C, when the pulse conversion movement amount of the focus lens in the drive state is inquired to the interchangeable lens side at the timing of α, constant rounding processing may be performed as internal processing on the interchangeable lens side. is there. The example of FIG. 10C shows the case where the internal processing is performed to cut off the position below the resolution on the interchangeable lens side. Unlike the example of the DC motor, when performing processing of cutting off the position below the resolution, a count error of about 0 to 1 pulse occurs in a fixed direction. On the other hand, when the focus lens is in the stop state, such an error does not occur because the focus lens is stopped at the position of 1/8 division shown in FIG.

  Next, with reference to FIG. 11, based on the examples described in (A) and (B), the influence of performing AF control of the contrast detection method in a state including error factors of the detection system will be described.

  FIG. 11A shows a waveform obtained in an AF scan operation of acquiring an AF evaluation value while driving a focus lens when the DC motor described in (A) is used as an actuator. In the case of a DC motor, in addition to the fact that the error of the detection system is 0 to 1 pulse and the influence of the error factor differs depending on the advancing direction of the focus lens, the waveform of the AF evaluation value according to the driving direction of AF scan operation Tends to shift with respect to the waveform of the ideal AF evaluation value.

  FIG. 11B shows an example in the case of performing processing of cutting off a position less than the resolution as internal processing of the interchangeable lens when obtaining the pulse conversion movement amount of the focus lens when the stepping motor is used as the actuator. . In this case, the waveform of the AF evaluation value tends to shift in a fixed direction with respect to the waveform of the ideal AF evaluation value, regardless of the driving direction of the AF scan operation.

  As shown in FIGS. 11 (a) and 11 (b), an error factor depending on the method of detecting the position information of the focus lens by the actuator and the detection system is a factor that reduces the focusing performance of the contrast AF. In addition, the impact differs depending on the difference in detection method. As described above, when the resolution on the camera body side takes into account the accuracy more than the resolution of the pulse conversion movement amount when the resolution of the pulse conversion movement amount of the focus lens obtained from the interchangeable lens side becomes coarse with respect to the focal depth. The error factor can not be ignored.

JP 2004-101946 A

  The present invention has been made in view of the above-described technical background, and provides a focus detection technique of an imaging device capable of improving the focusing accuracy in AF control regardless of the type of lens unit mounted. The purpose is to

An imaging apparatus according to the present invention is an imaging apparatus to which a lens unit having a focus lens driven in an optical axis direction is attachable / detachable, and includes: generating means for generating a focus evaluation value; Means, specifying means for specifying a method for calculating the amount of pulse conversion movement, which is position information of the focus lens, from identification information obtained from the lens unit via the communication means, and from the lens unit via the communication means Acquisition means for acquiring a pulse conversion movement amount which is position information of the focus lens, and the pulse conversion movement amount are corrected with an error component of the pulse conversion movement amount depending on the calculation method specified by the specifying means it is, correction and correcting means for calculating a converted pulse movement amount, the correction path calculated from the correction means and the focus evaluation value Focus detection means for detecting a focusing position on the basis of the scan converted moving amount, characterized in that it comprises a.

  According to the present invention, it is possible to improve the focusing accuracy in the AF control regardless of the type of lens unit to be mounted.

FIG. 1 is a block diagram showing an example of a system configuration of a digital single lens reflex camera which is a first embodiment of an imaging device of the present invention. FIG. 6 is a flowchart illustrating the basic operation of the digital single lens reflex camera shown in FIG. It is a figure which shows the example of the table information hold | maintained at the camera main body side. FIG. 6 is a flowchart illustrating AF processing in step S407 of FIG. 2; FIG. 5 is a flowchart illustrating a scan operation in steps S604 and S608 in FIG. 4. FIG. 6 is a flowchart illustrating a process of correcting an error component of a pulse conversion movement amount of a focus lens in step S615 of FIG. 5. FIG. 14 is a flowchart illustrating processing of switching control of a scanning operation based on a result of processing for identifying a pulse conversion movement amount calculation method of a focus lens in a digital single lens reflex camera according to a second embodiment of an imaging device of the present invention. . FIG. 8 is a flowchart showing an example of control switching in accordance with the drive method of the focus lens in the AF scan operation in step S803 in FIG. 7. FIG. 8 is a flowchart showing an example of control switching in accordance with the drive state of the focus lens at the time of acquisition of a pulse conversion movement amount in the AF scan operation in step S803 in FIG. 7. It is an explanatory view showing an example of a detection method of position information on a typical actuator and focus lens. It is a graph which shows the example of the waveform of AF evaluation value which received to the influence of the error factor of a detection type | system | group.

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

First Embodiment
FIG. 1 is a block diagram showing an example of the system configuration of a digital single-lens reflex camera which is a first embodiment of the imaging apparatus of the present invention.

  As shown in FIG. 1, in the digital single-lens reflex camera according to this embodiment, the interchangeable lens unit 100 is detachably mounted to a camera body 120 as an example of an apparatus body. In the mounted state, the lens unit 100 is communicably connected to the camera body 120 via the electrical contact unit 130.

  The lens unit 100 includes a first group lens 101, an aperture shutter 102, a second group lens 103, a focus lens 104, a zoom actuator 111, an aperture shutter actuator 112, and a focus actuator 113. The lens unit 100 further includes a zoom drive circuit 114, an aperture shutter drive circuit 115, a focus drive circuit 116, a lens MPU 118, and a lens memory 117.

  The first group lens 101 is disposed on the most object side of the lens unit 100, and is held movably back and forth in the optical axis direction. The diaphragm / shutter 102 adjusts the light amount at the time of shooting by adjusting the aperture diameter, and also functions as an exposure time adjustment shutter at the time of still image shooting.

  The aperture-shutter 102 and the second group lens 103 integrally move in the optical axis direction, and the zoom function is realized by interlocking with the advancing and retracting operation of the first group lens 101. The focusing lens 104 performs focusing by moving back and forth in the optical axis direction.

  The zoom actuator 111 drives the first group lens 101 and the third group lens 103 back and forth in the optical axis direction to perform a zoom operation. The aperture shutter actuator 112 controls the aperture diameter of the aperture / shutter 102 to adjust the imaging light amount, and performs exposure time control at the time of still image imaging. The focus actuator 113 drives the focus lens 104 in the optical axis direction to perform focusing.

  The zoom drive circuit 114 drives the zoom actuator 111 in accordance with the zoom operation of the photographer. The shutter drive circuit 115 drives and controls the diaphragm shutter actuator 112 to control the opening of the diaphragm shutter 102.

  The focus drive circuit 116 drives and controls the focus actuator 113 based on the focus detection result, and drives the focus lens 104 in the optical axis direction to perform focus adjustment. Here, depending on the type of actuator used as the focus actuator 113, the method of detecting the current position of the focus lens 104 differs.

  As described above, in the case of using a DC motor as the focus actuator 113, it is necessary to separately construct a encoder by incorporating a photo interrupter. The pulse signal indicating the movement amount of the actuator detected by the photo interrupter is correlated with the position of the focus lens, and therefore can be used as position information (pulse conversion movement amount of the focus lens) when performing focus adjustment.

  On the other hand, when a stepping motor is used as the focus actuator 113, it is characterized in that it rotates by one step in synchronization with the pulse signal supplied to the motor by the focus drive circuit 116, and the position detection mechanism is unnecessary. Therefore, since the pulse signal supplied to the motor has a correlation with the position of the focus lens, it can be used as position information (pulse conversion movement amount of the focus lens) when performing focus adjustment.

  The lens MPU 118 performs all calculations and controls related to the imaging optical system that causes the image pickup element 122 to form an image of the subject after the subject, and controls the zoom drive circuit 114, the shutter drive circuit 115, the focus drive circuit 116, and the lens unit 100 such as lens memory 117 Take control of the whole. The lens MPU 118 detects the current lens position, and notifies the camera MPU 125 of lens position information in response to a request from the camera MPU 125. The lens memory 117 stores optical information necessary for automatic focusing.

  The camera body 120 includes an optical low pass filter 121, an imaging element 122, an imaging element driving circuit 123, an image processing circuit 124, a camera MPU 125, a display 126, an operation switch group 127, a memory 128, and a TVAF focus detection unit 129.

  The optical low pass filter 121 reduces false color and moiré of a captured image. The image sensor 122 includes a CMOS sensor and its peripheral circuit, and one photoelectric conversion element is disposed on light receiving pixels of m pixels in the horizontal direction and n pixels in the vertical direction. The imaging element 122 is configured to be capable of independent output of all pixels.

  The image pickup device drive circuit 123 controls the operation of the image pickup device 122, A / D converts the acquired image signal, and transmits it to the camera MPU 125. The image processing circuit 124 performs γ conversion, color interpolation, JPEG compression, and the like of the image acquired by the imaging element 122.

  The camera MPU (processor) 125 performs all calculations and controls related to the camera body 120, and the imaging device drive circuit 123, the image processing circuit 124, the display 126, the operation switch group 127, the memory 128, the TVAF focus detection unit 129 Control.

  The camera MPU 125 is connected to the lens MPU 118 via the electrical contact unit 130, transmits lens position acquisition, a lens drive request with a predetermined drive amount to the lens MPU 118, and transmits optical information unique to the lens unit 100. Get it. Communication between the camera body 120 and the lens unit 100 via the electrical contact unit 130 is referred to as lens communication.

  The camera MPU 125 incorporates a ROM 125a storing a program for controlling the camera operation, a RAM 125b storing variables, and an EEPROM 125c storing various parameters. Also, the camera MPU 125 executes focus detection processing by the program stored in the ROM 125a. Details of the focus detection process will be described later.

  The display 126 is configured of an LCD or the like, and displays information on the shooting mode of the camera, a preview image before shooting and a confirmation image after shooting, an in-focus state display image at the time of focus detection, and the like. The operation switch group 127 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. The memory 128 is a removable memory, and records captured images.

  The TVAF focus detection unit 129 calculates an AF evaluation value (focus evaluation value) based on the contrast component of the image information obtained by the image processing circuit 124. In general, the AF evaluation value increases as the contrast, which is the contrast of the subject, increases, and the position of the focus lens at which the AF evaluation value becomes maximum is the in-focus position. The camera MPU 125 drives the focus lens 104 in the optical axis direction based on this AF evaluation value, and detects the position of the focus lens 104 at which the AF evaluation value becomes maximum.

  Next, with reference to FIG. 2, the basic operation of the digital single-lens reflex camera with the above configuration will be described. Note that each process in FIG. 2 is executed by the camera MPU 125 after the program held in the ROM 125 a of the camera body 120 is expanded on the RAM 125 b.

  In FIG. 2, in step S401, the camera MPU 125 determines whether the lens unit 100 is attached to the camera body 120. The electrical contact unit 130 is provided with a terminal for detection of attachment / detachment in addition to the terminal for communication, and it can be determined whether the lens unit 100 is connected to the camera body 120 or not. If the camera MPU 125 recognizes that the lens unit 100 is connected, the process proceeds to step S402.

  In step S402, the camera MPU 125 performs initial communication which is a preparation operation for starting lens communication via the electric contact unit 130, and proceeds to step S403.

  In the initial communication, after power supply to the lens unit 100, information exchange is performed between the camera body 120 and the lens unit 100 in accordance with a predetermined communication protocol to prepare for the subsequent camera operation. Information exchanged between the camera body 120 and the lens unit 100 specifies the camera body 120 and the lens unit 100 that are actually connected, since the camera body 120 and the lens unit 100 of a plurality of types are connected. There is identification information for In addition, there are optical information such as focal length and open F value, and function identification information indicating what kind of ability and function the camera body 120 and the lens unit 100 have.

  In step S403, the camera MPU 125 executes a process of specifying a method of calculating the pulse conversion movement amount of the focus lens 104, and proceeds to step S404. Although the details of the processing here will be described later, a method of calculating the pulse conversion movement amount of the focus lens 104 used in the lens unit 100 based on the information obtained from the lens unit 100 in the initial communication performed in step S402. Identify

  In step S404, the camera MPU 125 periodically drives the image sensor 122 with the image sensor drive circuit 123, processes the obtained image signal with the image processing circuit 124, and then displays it on the display 126. In step S405 move on. A through image is displayed on the display 126, and the photographer performs adjustment of the angle of view, etc. while viewing the through image.

  In step S405, the camera MPU 125 determines the state of the release switch included in the operation switch group 127. In the present embodiment, the release switch is a two-stage switch. When the release button (not shown) of the camera body 120 is half-pressed, the first-stage release switch SW1 is turned on, and when fully pressed, the second-stage release switch SW2 is turned on. Then, when the release button is pressed halfway and the first stage release switch SW1 is turned on, the camera MPU 125 proceeds to step S406.

  In step S406, the camera MPU 125 performs exposure control so as to be an exposure condition suitable for AF processing in preparation for the AF processing in step S407, and proceeds to step S407. Generally, when performing AF processing, it is desirable that the aperture be in the open state. Therefore, the camera MPU 125 controls the aperture / shutter 102 to be open by lens communication via the electrical contact unit 130, and controls the exposure time and the signal amplification amount of the image sensor 122 using the image sensor drive circuit 123.

  In step S407, the camera MPU 125 controls the drive of the focus lens 104 of the lens unit 100 by lens communication via the electrical contact unit 130 to perform focus adjustment, and proceeds to step S408. Details of the focus detection process here will be described later.

  In step S408, when the release button is fully pressed and the second stage release switch SW2 is turned on, the camera MPU 125 proceeds to step S409.

  In step S409, the camera MPU 125 performs a shooting process. Specifically, the camera MPU 125 controls the aperture / shutter 102 by lens communication via the electrical contact unit 130 to operate the shutter, and reads an image signal from the image sensor 122. Then, the camera MPU 125 A / D converts the image signal read from the image sensor 122 by the image sensor drive circuit 123, processes it in the image processing circuit 124, and records the JPEG-compressed image file in the memory 128. After completion of the series of shooting processes, the process returns to step S404 to prepare for the next shooting.

  Next, the process of specifying the method of calculating the amount of pulse conversion movement of the focus lens 104 in step S403 of FIG. 2 will be described. The specific processing here is the characteristic and tendency when the lens MPU 118 calculates the pulse conversion movement amount of the focus lens based on the detection result of the drive amount by the focus actuator 113 and the focus drive circuit 116 used in the lens unit 100. Identify.

  Here, in the present embodiment, methods 1 and 2 are used as the focus lens pulse conversion movement amount calculation method.

  In the method 1, as in the example of the DC motor, while the resolution of the detection system for detecting the drive amount of the focus actuator 113 matches the pulse conversion movement amount, the drive of the focus lens 104 depends on the detection method of the detection system. It is a case where it has a fixed error tendency depending on the direction.

  Method 2 is a position within the lens MPU 118 of the lens unit 100 with a higher resolution than the pulse conversion movement amount of the focus lens supplied to the camera body 120 by lens communication via the electric contact unit 130 as in the example of the stepping motor. Manage information. When the pulse conversion movement amount is supplied to the camera body 120 by lens communication, the pulse conversion movement amount of the focus lens is calculated by performing processing for discarding the position below the resolution.

  In this embodiment, the discrimination information of the calculation method of the pulse conversion movement amount of the focus lens to function identification information indicating what kind of capability and function the lens unit 100 has by the initial communication performed in step S402 of FIG. An example including (scheme type) is shown. That is, it is assumed that a method type that directly indicates each method can be acquired as determination information obtained from the lens unit 100 by the camera body 120 through lens communication.

  In the EEPROM 125 c of the camera MPU 125, as shown in FIG. 3A, table information in which “Sa: system type”, “Sb: error correction value”, and “Sc: influence according to the state of the actuator” is summarized Hold. “Sa: scheme type” is specified with the scheme type obtained in the initial communication as a key value. Then, "Sb: error correction value" determined by the specified "Sa: method type" and "Sc: influence according to the state of the actuator" will be described later AF processing and correction processing of the pulse conversion error component of the focus lens Will be used in

  In addition, there may be a case where the system type can not be obtained directly by the initial communication. That is, an example may be considered in which the method of calculating the pulse conversion movement amount of the focus lens is specified from other information. For example, in the case where information on the type of actuator can be acquired by initial communication, and in the case where a method is uniquely associated with the type of actuator, the table information shown in FIG. The configuration to be

  Furthermore, it is also possible to manage the method for each type of lens unit 100. That is, as shown in FIG. 3C, the table information for associating the identification information (lens ID) for identifying the lens unit 100 obtained by the initial communication with the system is also matched with the EEPROM 125 c of the camera MPU 125 and held. Conceivable.

  In the present embodiment, two types of method 1 and method 2 are illustrated as a method of calculating the pulse conversion movement amount of the focus lens, but the present invention is not limited to this. For example, as a process of rounding up the position below the resolution instead of cutting off the position below the resolution in the system 2, an error correction amount in that case may be separately set, and this may be set as the system 3. That is, the method adopted by the lens unit 100 may be specified, and the influence thereof can be grasped by the camera body 120 side.

  Next, with reference to FIG. 4, the AF processing in step S407 of FIG. 2 will be described. In the AF processing in the present embodiment, an example is shown in which two scanning operations of a rough scanning operation and a fine scanning operation are performed on an AF scanning operation for acquiring an AF evaluation value and a pulse conversion movement amount of a focus lens in association. In the coarse scan operation, the focus actuator 113 is controlled to specify a rough in-focus position so that the interval becomes coarse. In the fine scan operation, the focus actuator 113 is controlled to narrow the interval to specify an accurate in-focus position.

  In FIG. 4, in step S601, the camera MPU 125 moves the focus lens 104 to an initial position at the time of performing the AF processing, and proceeds to step S602. In this embodiment, the position of the infinite end of the movable range of the focus lens 104 is set as the initial position, and the focus lens 104 of the lens unit 100 is moved to the target position by lens communication via the electric contact unit 130.

  In step S602, the camera MPU 125 determines whether the focus lens 104 has reached the position of the infinite end which is the target position. If the focus lens 104 has reached the target position, the process proceeds to step S603.

  In step S603, the camera MPU 125 determines drive conditions in the coarse scan operation, and proceeds to step S604. In the present embodiment, it is assumed that the drive condition for acquiring the AF evaluation value is determined while moving the focus lens 104 in the optical axis direction continuously, and the target position is set at the closest end.

  Further, in accordance with the calculation period of the AF evaluation value, the drive speed of the focus lens 104 is determined so that the change in the pulse conversion movement amount of the focus lens 104 becomes a predetermined interval. In this case, the AF evaluation value can be continuously acquired by determining the target position and the driving speed so that the movement of the focus lens 104 is not completed within the calculation period of the AF evaluation value.

  In step S604, the camera MPU 125 performs an AF scan operation, and proceeds to step S605. As described above, the AF scan operation is an operation for correlating and acquiring the AF evaluation value and the pulse conversion movement amount of the focus lens, and searching for the peak position in the peak waveform of the AF evaluation value. Details of the AF scan operation will be described later with reference to FIG.

  In step S605, the camera MPU 125 determines whether or not the peak position has been detected in the rough scan operation of step S604. If it has been detected, the process proceeds to step S607. If it has not been detected, the process proceeds to step S606. .

  In step S606, the camera MPU 125 determines whether the focus lens 104 has reached an end. In the present embodiment, it is assumed that the focus lens 104 has reached the near end while the peak position can not be detected. Therefore, when the focus lens 104 has not reached the end, the camera MPU 125 returns to step S603, and continues peak position detection by a series of rough scan operations from step S603 to step S606. On the other hand, when the focus lens 104 reaches the end, the camera MPU 125 ends the process as out-of-focus because the in-focus position can not be specified.

  In step S607, the camera MPU 125 determines driving conditions in the fine scan operation, and proceeds to step S608. The basic processing contents here are the same as the determination of the drive conditions in the rough scan operation in step S603, but the focus lens 104 is set so that the interval when acquiring the AF evaluation value is finer than the rough scan operation. The point of determining the driving conditions of

  In the present embodiment, assuming that the focus position is converged in the vicinity by the rough scan operation, the advancing direction of the focus lens 104 is reversed to set the target position to the peak position of the rough scan operation. Set as a position beyond the quantitative. The predetermined amount is set as a predetermined amount of three intervals of the pulse conversion movement amount of the focus lens 104 when periodically acquiring the AF evaluation value set in the fine scan operation.

  In step S608, the camera MPU 125 performs an AF scan operation, and proceeds to step S609. The processing content here is the same as the processing content in step S604 except that the drive condition of the focus lens 104 is different. Details of the AF scan operation will be described later with reference to FIG.

  In step S609, the camera MPU 125 determines whether the peak position has been detected in the scan operation in step S608. Then, when the peak position of the fine scan operation can not be detected, the camera MPU 125 returns to step S607, and continues the peak position detection by the series of fine scan operations from step S607 to step S609. On the other hand, when the peak position of the fine scan operation can be detected, the camera MPU 125 proceeds to step S610.

  In step S610, the camera MPU 125 drives the focus lens 104 toward the peak position identified by the fine scan operation, that is, the in-focus position, and the process proceeds to step S611.

  In step S611, the camera MPU 125 determines whether the focus lens 104 driven in step S610 has reached the target position. If the focus position has reached the target position, the process ends.

  Next, with reference to FIG. 5, the scan operation in step S604 and step S608 in FIG. 4 will be described.

  In FIG. 5, in step S612, the camera MPU 125 determines whether generation of the AF evaluation value is completed by the TVAF focus detection unit 129. If completed, the process proceeds to step S613.

  In step S613, the camera MPU 125 acquires the AF evaluation value generated by the TVAF focus detection unit 129, stores the AF evaluation value in the RAM 125b, and proceeds to step S614.

  In step S614, the camera MPU 125 acquires the pulse conversion movement amount of the focus lens from the lens unit 100 by lens communication via the electric contact unit 130, and proceeds to step S615.

  In step S615, the camera MPU 125 corrects the error component caused by the feature or tendency when the lens MPU 118 calculates the pulse conversion movement amount with respect to the focus lens pulse conversion movement amount acquired in step S614, and proceeds to step S616. . The error component here is obtained based on the detection result of the drive amount by the focus actuator 113 and the focus drive circuit 116 used in the lens unit 100 as described above in the example of the DC motor / stepping motor.

  In addition, since the correction amount of the error component is a value less than the resolution of the pulse conversion movement amount that can be acquired by lens communication, in this embodiment, 10 times the pulse conversion movement amount is used as position information of the focus lens. I assume. In addition, the pulse conversion movement amount (ten-fold value) after error correction is stored in the RAM 125 b of the camera MPU 125. Therefore, a series of AF evaluation values and a correction pulse conversion movement amount (ten-fold value) obtained by correcting the error component of the pulse conversion movement amount are stored in association with each other in the RAM 125 b. Details will be described later.

  In step S616, the camera MPU 125 calculates the peak position based on the series of AF evaluation values stored in the RAM 125b and the correction pulse conversion movement amount (ten-fold value) obtained by correcting the error component of the pulse conversion movement amount. And go to step S617. When calculating the peak position, the AF evaluation value increases as the contrast, which is the contrast of the subject, increases, and decreases as the contrast decreases. Therefore, with reference to a series of AF evaluation values stored in the RAM 125b, it is determined whether or not the waveform produced by the AF evaluation value has reached a size sufficient to determine that the image is in focus, and then the peak position is calculated. On the other hand, when the waveform produced by the AF evaluation value does not reach a sufficient size, it is regarded as out of focus and the peak position is not calculated.

  In the case of obtaining the peak position in the above example, the position of the focus lens 104 at the maximum value of the waveform formed by the AF evaluation value is obtained. At that time, since the combination of the AF evaluation value and the corresponding correction pulse conversion movement amount (ten-fold value) is discretely acquired, the actual peak position is calculated using an interpolation operation or the like when calculating the maximum value. calculate. As described above, it is possible to reflect an error component of less than one pulse in the final calculation process of the peak position, so that the focusing accuracy can be improved.

  In addition, since the peak position to be calculated is used to move the focus lens 104 of the lens unit 100 finally through lens communication via the electric contact unit 130, it is necessary to return to the resolution of the normal pulse conversion movement amount . Therefore, the calculated peak position is finally reduced to 1/10, and becomes a peak position returned to the resolution of the normal pulse conversion movement amount of the focus lens 104 by rounding off after the decimal point.

  In step S617, the camera MPU 125 determines whether or not the peak position can be identified. If the peak position can be identified, the process proceeds to step S620. If the peak position can not be identified, the process proceeds to step S618.

  In step S620, the camera MPU 125 stops the focus lens 104 and ends the process.

  In step S618, the camera MPU 125 determines whether or not the focus lens 104 has reached the target position set in step S603 or step S607. The process proceeds to step S619.

  In step S619, the camera MPU 125 drives the focus lens 104 to the set target position, and ends the process.

  Thus, the processing from step S612 to step S618 is continuously performed until the focus lens 104 reaches the target position or the peak position can be identified.

  Next, with reference to FIG. 6, the process of correcting the error component of the pulse conversion movement amount of the focus lens 104 in step S615 of FIG. 5 will be described. Here, with respect to the pulse conversion movement amount which is position information of the focus lens used in the AF processing, an error component depending on the calculation method specified in the specific processing of the pulse conversion movement amount calculation method in step S403 of FIG. to correct.

  In FIG. 6, in step S701, the camera MPU 125 multiplies the pulse conversion movement amount of the focus lens 104 obtained in step S614 in FIG. 5 by 10 and proceeds to step S702. The reason for multiplying the amount of pulse conversion movement by 10 is to reflect a correction value of an error component less than the resolution of the pulse conversion movement amount described later.

  In step S702, the camera MPU 125 determines whether or not the method of calculating the amount of pulse conversion movement identified in step S403 in FIG. 2 is method 1, and in the case of method 1, proceeds to step S703. In the present embodiment, only the two patterns of method 1 and method 2 are assumed as the method of calculating the amount of pulse conversion movement, so if the method is not method 1, the camera MPU 125 proceeds to step S706 as method 2.

  In step S703, the camera MPU 125 determines whether the current drive direction of the focus lens 104 is ∞ → close direction or close → ∞ direction, and in the case of →→ close direction, the process proceeds to step S704 and the close direction → 至 近 direction The process proceeds to step S705.

  In step S704, based on the table information of “Sa: method type” and “Sb: error correction value” stored in the EEPROM 125 c, the camera MPU 125 sets ∞ of method 1 with respect to the original pulse conversion movement amount (10 times value). → Add the error correction value in the near direction. Then, the camera MPU 125 stores the pulse conversion movement amount (ten-fold value) after error correction in the RAM 125 b and ends the processing.

  In step S705, the camera MPU 125 sets the closeness of method 1 to the original pulse conversion movement amount (10 times value) based on the table information of "Sa: method type" and "Sb: error correction value" held in the EEPROM 125c. → Add the error correction value in the ∞ direction. Then, the camera MPU 125 stores the pulse conversion movement amount (ten-fold value) after error correction in the RAM 125 b and ends the processing.

  In step S706, the camera MPU 125 determines whether the current drive direction of the focus lens 104 is ∞ → close direction or close → ∞ direction, and in the case of →→ close direction, the process proceeds to step S707 and the close direction → ∞ direction The process proceeds to step S 708.

  In step S 707, the camera MPU 125 sets ∞ of the method 2 with respect to the original pulse conversion movement amount (10-fold value) based on the table information of “Sa: method type” and “Sb: error correction value” held in the EEPROM 125 c. → Add the error correction value in the near direction. Then, the camera MPU 125 stores the pulse conversion movement amount (ten-fold value) after error correction in the RAM 125 b and ends the processing.

  In step S 708, the camera MPU 125 sets the approach distance of method 2 close to the original pulse conversion movement amount (10 times value) based on the table information of “Sa: method type” and “Sb: error correction value” held in the EEPROM 125 c. → Add the error correction value in the ∞ direction. Then, the camera MPU 125 stores the pulse conversion movement amount (ten-fold value) after error correction in the RAM 125 b and ends the processing.

  As described above, in the present embodiment, when the method of calculating the pulse conversion movement amount of the focus lens 104 adopted by the lens unit 100 is method 1, the error correction value for ± β is original according to the advancing direction of the focus lens 104. Is added to the pulse conversion movement amount of. When the calculation method is method 2, an error correction value for + β is added to the original pulse conversion movement amount regardless of the traveling direction of the focus lens 104.

  Thereby, the shift tendency of the waveform of the AF evaluation value and the pulse conversion movement amount due to the error component depending on the calculation method of the pulse conversion movement amount of the focus lens 104 as shown in FIG. 11A and FIG. It is possible to In the present embodiment, the error correction value β is set to 5. This shows an example in which the error of the pulse conversion movement amount of the focus lens 104 that can be generated is 0 to 1 pulse, and a value 10 times the median value 0.5 is set.

  As described above, in the present embodiment, the AF processing is performed after correcting an error component depending on the drive actuator of the focus lens 104 mounted on the lens unit 100 and the detection method of the drive amount thereof. As a result, regardless of the type of lens unit 100 mounted on the camera body 120, focus detection with higher accuracy can be realized, and focusing accuracy can be improved.

Second Embodiment
Next, with reference to FIG. 7 to FIG. 9 and the like, a digital single-lens reflex camera which is a second embodiment of the imaging device of the present invention will be described. Note that parts corresponding to or overlapping with the first embodiment will be described using the drawings and reference numerals.

  As described above, the occurrence of an error component depending on the actuator for driving the focus lens and the detection method of the drive amount may change depending on the operating state of the actuator. That is, in the case of a DC motor, it is affected by an error related to the drive state and the stop state, but in the case of a stepping motor, it is affected by an error in the drive state and is not affected by the error in the stop state. Therefore, the EEPROM 125 c of the camera MPU 125 holds the table information of “Sa: method type”, “Sb: error correction value”, and “Sc: influence according to the state of the actuator” as shown in FIG. ing. As a result, it is possible to specify the pulse conversion movement amount calculation method of the focus lens. In addition, it is possible to specify what kind of tendency “Sc: influence according to the state of the actuator” tends to be for each calculation method of the pulse conversion movement amount.

  In this embodiment, based on the table information shown in FIG. 3A, in the AF processing, correction processing of the error component of the pulse conversion movement amount of the focus lens 104 is performed according to the control method and operation state of the focus lens 104. The case of switching whether to do or not is taken as an example.

  Some lens units 100 mounted on the camera body 120 can not be finely controlled in speed when the focus lens 104 is driven. For example, an interchangeable lens based on a single-lens reflex camera of a silver halide film equipped with a focus adjustment function of a phase difference detection method with a dedicated distance measurement sensor corresponds, and a focus of contrast detection method based on a video signal from an imaging device There are cases where control by adjustment is not assumed.

  In general, in the case of focus adjustment of the phase difference detection method, it is required to drive the focus lens at a higher speed, while in focus adjustment of the contrast detection method, the acquisition interval of the AF evaluation value is set as a predetermined interval. Therefore, a configuration capable of speed control corresponding to lower speeds is required.

  In the case of using an interchangeable lens which can not finely control the speed based on focus adjustment of the phase difference detection method in focus adjustment of the contrast detection method, it is necessary to change drive control of the focus lens in AF scan operation.

  In the first embodiment, the scan operation for acquiring the AF evaluation value while moving the focus lens continuously in FIGS. 4 and 5 has been described. On the other hand, as described above, in the interchangeable lens based on the focus adjustment of the phase difference detection method, since the speed control of the focus lens can not be finely performed, the acquisition interval of the AF evaluation value is controlled by the operation of the intermittent focus lens. Do. The specific method will be described below.

  In this embodiment, the movement of the focus lens 104 is completed within the calculation period of the AF evaluation value in the drive condition determination of the coarse scan operation in step S603 of FIG. 4 and the drive condition determination of the fine scan operation in step S607. Determine the target position and drive speed. As shown in steps S603 to S606 and S607 to S609 in FIG. 4, the drive condition in the AF scan operation can be periodically updated until the focus lens 104 reaches an end or the peak position can be detected. . Therefore, by updating the target position as described above, it is possible to intermittently drive the focus lens 104 and acquire the AF evaluation value at predetermined intervals.

  In the present embodiment, the AF can operation for continuously driving the focus lens 104 to acquire an AF evaluation value and the AF can operation for intermittently driving the focus lens 104 to acquire an AF evaluation value according to the type of the lens unit 100 It is assumed that the control is performed separately. At that time, if the occurrence of the error component depending on the actuator for driving the focus lens 104 and the detection method of the drive amount changes depending on the operation state of the actuator, it is necessary to appropriately handle the influence. is there.

  FIG. 7 is a flow chart for explaining the process of switching the control of the scanning operation based on the result of the process of specifying the pulse conversion movement amount calculation method of the focus lens 104. The switching process of the scan operation is performed in place of the scan operation of steps S604 and S608 in FIG.

  In FIG. 7, in step S801, the camera MPU 125 refers to the table information shown in FIG. 3A stored in the EEPROM 125c. Then, the camera MPU 125 reads “Sc: influence according to the state of the actuator” based on the calculation method of the pulse conversion movement amount adopted by the lens unit 100 currently mounted, and proceeds to step S802.

  In "Sc: Influence according to the state of the actuator", it is possible to specify the presence or absence of the occurrence of an error of the pulse conversion movement amount according to the operation state of the actuator that drives the focus lens 104. Therefore, it is possible to determine whether the tendency of the influence of the error is different between the drive state and the stop state of the actuator.

  In step S802, the camera MPU 125 determines whether the occurrence of an error is different between the driving state and the stopping state of the actuator. If not different, the process proceeds to step S804 to execute a series of processes shown in FIG. finish. On the other hand, when the presence or absence of error occurrence differs between the driving state and the stopping state of the actuator, the camera MPU 125 proceeds to step S803, implements the scanning operation of FIG. 8 or 9 described later, and ends the processing.

  FIG. 8 is a flowchart showing an example of control switching in accordance with the drive method of the focus lens 104 in the AF scan operation in step S803 of FIG. In addition, since the process except the part enclosed with the broken line of a figure is the same as the process of FIG. 5, the description is abbreviate | omitted.

  In step S904, the camera MPU 125 determines whether the driving method in the current AF scan operation is continuous scan or intermittent scan. If continuous scan, the process proceeds to step S905, and if intermittent scan, the process proceeds to step S906. As described above, since the method of setting the target position in intermittent scanning is different from that in the case of continuous scanning, it is possible to determine which drive system the actuator is operating. The configuration to be separately information for determining whether adopting the previously which drive system in fine scan driving condition determining in the rough scan driving condition determining and step S607 in step S603 of FIG. 4 and not recorded from the target position Is also conceivable.

  In step S905, the camera MPU 125 performs correction processing of an error component of the pulse conversion movement amount of the focus lens 104 similar to step S615 in FIG. 5, and proceeds to step S907.

  In step S906, the camera MPU 125 calculates a 10-fold value of the pulse conversion movement amount before correction of the focus lens 104 acquired in step S903, stores the calculated value in the RAM 125b, and proceeds to step S907.

  FIG. 9 is a flowchart showing an example of control switching in accordance with the drive state of the focus lens 104 at the time of acquisition of the pulse conversion movement amount in the AF scan operation in step S 803 of FIG. In addition, since the process except the part enclosed with the broken line of a figure is the same as the process of FIG. 5, the description is abbreviate | omitted.

  In step S915, the camera MPU 125 acquires the drive state of the focus lens 104 by lens communication via the electrical contact unit 130, and proceeds to step S916. This is to check the drive state of the focus lens 104 at the time of acquiring the pulse conversion movement amount in the previous step S914.

  In step S916, the camera MPU 125 determines whether or not the drive state of the focus lens 104 at the time of acquisition of the pulse conversion movement amount is the stop state. If it is not the stop state, the process proceeds to step S917. Proceed to step S918.

  In step S917, the camera MPU 125 performs correction processing of the pulse conversion error component of the focus lens 104, and proceeds to step S919.

  In step S918, the camera MPU 125 calculates a 10-fold value of the pulse conversion movement amount before correction of the focus lens 104 obtained in step S914, stores the calculated value in the RAM 125b, and proceeds to step S919.

  As described above, in the present embodiment, even if the presence or absence of an error component depending on the actuator and the method of detecting the amount of drive thereof changes depending on the operating state of the actuator, the type of lens unit 100 mounted is Regardless, it is possible to perform focus detection with higher accuracy. Other configurations and effects are the same as those of the first embodiment.

Third Embodiment
Next, a digital single-lens reflex camera which is a third embodiment of the imaging device of the present invention will be described. Note that parts corresponding to or overlapping with the first and second embodiments will be described using the drawings and reference numerals.

  In the present embodiment, the correction processing of the error component of the pulse conversion movement amount of the focus lens 104 in step S615 etc. of FIG. 5 is performed according to the drive condition of the focus lens 104 in the AF scan operation and the contents of the process to be executed. The case of switching whether to do or not is taken as an example. By not performing the correction process of the error component of the pulse conversion movement amount of the focus lens 104, the processing load of the camera MPU 125 can be reduced.

  Hereinafter, three methods will be described as an example in which the correction processing of the error component of the pulse conversion movement amount of the focus lens 104 is not performed.

(1) Method Based on Relationship with Focal Depth Although various lens units 100 may be connected to the camera body 120, depending on the optical performance of the connected lens unit 100, the pulse conversion of the focus lens 104 may be performed. There is one that does not need to perform correction processing of the error component of the movement amount. Specifically, the resolution of the pulse conversion movement amount of the focus lens 104 is sufficiently ensured, and the error component of the pulse conversion movement amount is sufficiently smaller than the focal depth converted to the pulse conversion movement amount. It is.

  For example, when the pulse conversion movement amount of the focal depth is a predetermined amount or more (for example, 5 pulses or more) as a threshold of determination, control is performed so as not to execute the correction processing of the error component of the pulse conversion movement amount of the focus lens 104. By applying this control, the processing load of the camera MPU 125 is reduced when the corresponding lens unit 100 is connected to the camera body 120 by intentionally not performing the correction processing of the error component of the pulse conversion movement amount. It is possible to

(2) Method Based on Relationship with Scan Interval In addition, a method of determining the presence or absence of correction processing of the error component of the pulse conversion movement amount of the focus lens 104 based on the interval (scan interval) for acquiring the AF evaluation value. Is also conceivable. For example, in the rough scan drive condition determination in step S603 in FIG. 4 and the fine scan drive condition determination in step S607, an error occurs when the interval for acquiring the AF evaluation value is equal to or more than a predetermined amount (for example, 10 pulses or more). Control is performed so that the component correction process is not performed. By applying this control, the processing load of the camera MPU 125 is reduced when the corresponding lens unit 100 is connected to the camera body 120 by intentionally not performing the correction processing of the error component of the pulse conversion movement amount. It is possible to

(3) Method Based on Processing Content of AF Processing Further, a method of determining whether to perform correction processing of an error component of the pulse conversion movement amount of the focus lens 104 based on the processing content of the AF processing may be considered. For example, as described in FIG. 4 of the first embodiment, it is assumed that a rough peak position is detected by a coarse scan and a final focus position is specified by a fine scan. Then, when performing the coarse scan, the correction process of the error component of the pulse conversion movement amount is not performed, and the correction process of the error component of the pulse conversion movement amount is performed only when the thin scan specifying the final focusing position is performed. Control to implement. By applying this control, the processing load of the camera MPU 125 is reduced when the corresponding lens unit 100 is connected to the camera body 120 by intentionally not performing the correction processing of the error component of the pulse conversion movement amount. It is possible to

  As described above, in the present embodiment, whether the correction processing of the error component of the pulse conversion movement amount of the focus lens 104 is performed according to the drive condition of the focus lens 104 in the AF scan operation and the contents of the processing to be executed Control to switch whether or not. As a result, correction processing of the error component of the pulse conversion movement amount is performed when necessary to ensure focusing accuracy, and when unnecessary, correction processing of the error component of the pulse conversion movement amount is intentionally performed. By not implementing the processing, the processing load of the camera MPU 125 can be reduced. Other configurations and effects are the same as those of the first and second embodiments.

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

  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).

100 lenses unit 104 focus lens 113 focus actuator 116 focus drive circuit 118 lens MPU
120 Camera body 125 Camera MPU
130 Electric contact unit

Claims (11)

An imaging apparatus to which a lens unit having a focus lens driven in an optical axis direction is attachable and detachable.
Generation means for generating a focus evaluation value;
Communication means for communicating information with the lens unit;
Specifying means for specifying a calculation method of a pulse conversion movement amount which is position information of the focus lens from identification information acquired from the lens unit via the communication means;
An acquisition unit configured to acquire a pulse conversion movement amount which is position information of the focus lens from the lens unit via the communication unit;
It said converted pulse movement amount, by correcting an error component of the converted pulse shift amount that depends on the calculation method identified by the identifying means, and correcting means for calculating a correction pulse converted moving amount,
An image pickup apparatus comprising: focus detection means for detecting an in-focus position based on the focus evaluation value and the correction pulse conversion movement amount calculated by the correction means.   The imaging apparatus according to claim 1, wherein the identification information is identification information of the lens unit.   The imaging apparatus according to claim 1, wherein the identification information is identification information of an actuator that drives the focus lens, and a detection system that detects an amount of drive of the focus lens by the actuator. When the focus detection means intermittently moves the focus lens, the pulse conversion before correction is performed by converting the correction pulse conversion movement amount calculated by the correction means into the resolution of the correction pulse conversion movement amount. The imaging apparatus according to any one of claims 1 to 3, wherein the amount of movement is switched. The focus detection unit is calculated by the correction unit when specifying the in-focus position according to the operation state of an actuator that drives the focus lens when acquiring the pulse conversion movement amount by the acquisition unit. The image pickup apparatus according to any one of claims 1 to 3 , wherein the correction pulse conversion movement amount is switched to the pulse conversion movement amount converted to the resolution of the correction pulse conversion movement amount. When the error component is smaller than a predetermined amount with respect to the depth of focus converted to the pulse conversion movement amount, the focus detection unit does not execute the correction of the error component by the correction unit, and the focus position is determined. The imaging device according to any one of claims 1 to 5, wherein when identifying, the pulse conversion movement amount before correction converted to the resolution of the correction pulse conversion movement amount is used. The focus detection means specifies the in-focus position without correcting the error component by the correction means when the error component is smaller than a predetermined amount with respect to an interval for obtaining the focus evaluation value. The imaging device according to any one of claims 1 to 5, wherein the pulse conversion movement amount before correction converted to the resolution of the correction pulse conversion movement amount is used at the time. The focus detection means stores the focus evaluation value and the correction pulse conversion movement amount in association with each other, and stores the series of focus evaluation values stored and the correction pulse conversion stored in association with the focus evaluation value. The focus position is detected by calculating the position of the focus lens in which the focus evaluation value indicates the maximum value based on the movement amount, according to any one of claims 1 to 7. Imaging device. The imaging apparatus according to any one of claims 1 to 8, wherein the error component includes a value less than the resolution of the pulse conversion movement amount. A method of controlling an imaging apparatus capable of attaching and detaching a lens unit having a focus lens driven in an optical axis direction, comprising:
Generating a focus evaluation value;
A specifying step of specifying a method of calculating a pulse conversion movement amount which is position information of the focus lens from the identification information acquired from the lens unit;
An acquiring step of acquiring a pulse conversion movement amount which is position information of the focus lens from the lens unit;
It said converted pulse movement amount, by correcting an error component of the converted pulse shift amount that depends on the calculation method specified in the specifying step, a correction step of calculating a correction pulse converted moving amount,
Control method for an imaging apparatus according to claim Rukoto to have a, a focus detection step of detect an in-focus position based on the correction pulse conversion movement amount calculated in the correction step and the focus evaluation value. A program for controlling an imaging device capable of attaching and detaching a lens unit having a focus lens driven in an optical axis direction,
Generating a focus evaluation value;
A specifying step of specifying a method of calculating a pulse conversion movement amount which is position information of the focus lens from the identification information acquired from the lens unit;
An acquiring step of acquiring a pulse conversion movement amount which is position information of the focus lens from the lens unit;
It said converted pulse movement amount, by correcting an error component of the converted pulse shift amount that depends on the calculation method specified in the specifying step, a correction step of calculating a correction pulse converted moving amount,
A program characterized by executing a focus detection step for detect an in-focus position based on the correction pulse conversion movement amount calculated in the correction step and the focus evaluation value, to the computer.