JP2016114721A - Imaging apparatus and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable acquisition of an AF adjustment value stably and highly accurately. As an adjustment mode for acquiring an AF adjustment value for adjusting a focus detection result by a first focus detection unit of a phase difference detection method, a mode selected from a plurality of images in different focus states is selected. A first mode for calculating the AF adjustment value based on the focus state of the image and a second mode for calculating the AF adjustment value based on the focus detection result by the second focus detection means of the imaging surface phase difference detection method. Prepare. In the focus detection area that is the target for calculating the AF adjustment value, the first mode and the second mode are switched according to the detection direction of the defocus amount by the first focus detection means. [Selection] Figure 8

Description

  The present invention relates to an imaging apparatus having an automatic focus adjustment function.

  As an automatic focus adjustment function (AF) of an imaging apparatus such as a single-lens reflex camera, the focus state (defocus amount) of the imaging optical system is determined from the phase difference between a pair of image signals formed by light passing through the imaging optical system in the interchangeable lens AF using a phase difference detection method for detecting) is known. When focusing using such phase difference detection AF, focus errors may occur due to various causes. For example, particularly in the case of an interchangeable lens camera system, both the camera body and the interchangeable lens include manufacturing errors (for example, the position where the focus lens is actually driven with respect to the input drive signal). There is. Alternatively, it may include an error of a correction value for correcting the AF result (for example, a value for correcting a deviation between the calculation result of the focus lens position based on the focus detection result and the focus lens position where the focus is truly obtained). is there. If there is such an error, there is a possibility that the focus is shifted more than the allowable amount.

  Therefore, a function (AF microadjustment) for allowing the user to arbitrarily finely adjust the AF result by the phase difference detection method is known. In this function, the user sets a desired AF adjustment value in the imaging apparatus in advance, and adjusts the focus position using the set AF adjustment value when performing focus adjustment during actual shooting.

  However, according to the conventional method, in order to obtain a focus image expected by the user, it is necessary to repeat an operation of inputting an AF adjustment value and an operation of confirming an image by photographing with the set AF adjustment value. Therefore, a method has been proposed for allowing a user to set a desired AF adjustment value more easily.

  Patent Document 1 discloses that a focus lens is moved by a predetermined width and images are automatically captured sequentially at a plurality of different lens positions (focus bracket imaging). Then, it is disclosed that a correction value for performing phase difference detection AF is determined based on a focus position displacement amount corresponding to an image selected by a user from a plurality of captured images. Yes.

  Further, in Patent Document 2, an image sensor is provided with a focus detection pixel, and a sensor-specific phase difference detection method using an AF result of an imaging surface phase difference detection method and an AF result of a sensor-specific phase difference detection method. It is disclosed to determine a correction value when performing AF.

JP 2005-109621 A JP 2010-113073 A

  When a user selects a desired focus image from a plurality of bracketed images as in Patent Document 1, the focus accuracy of the AF adjustment value depends on the user's judgment. Also, when the true in-focus position is in the middle of two consecutive images, it is not possible to obtain an AF adjustment value for accurately focusing. Therefore, when the imaging plane phase difference detection method is used as in Patent Document 2, it is expected that a highly accurate AF adjustment value is obtained by performing focus detection with a finer pixel pitch.

  However, due to the characteristics of the imaging surface phase difference detection method, there are cases where the imaging surface phase difference AF cannot be used, and even if it can be used, the reliability of the detection result is lowered. In such a case, an accurate AF adjustment value cannot be obtained by the method of Patent Document 2.

  Accordingly, an object of the present invention is to make it possible to acquire an AF adjustment value stably and with high accuracy.

  In order to achieve the above object, the present invention is an imaging apparatus having an adjustment mode for acquiring an adjustment value used for adjusting a focus detection result for at least one focus detection region, and comprising a phase difference detection method A pixel that generates an image signal to be used for focus detection, an imaging processing unit that photoelectrically converts an object image to capture an image, and defocusing based on an image signal that is different from the image signal output from the imaging processing unit First focus detection means for detecting the amount, second focus detection means for detecting the defocus amount based on the image signal output from the imaging processing means, control means for controlling the position of the focus lens, Calculation means for calculating the adjustment value used for adjustment of the detection result by the first focus detection means, and the adjustment mode allows the user to select from a plurality of images in different focus states. A first mode for calculating the adjustment value based on a focus state of the selected image, and a second mode for calculating the adjustment value based on a detection result by the second focus detection unit, The first mode and the second mode are switched in the focus detection region that is an adjustment value calculation target according to a detection direction of a defocus amount by the first focus detection unit. .

  According to the present invention, it is possible to stably and highly accurately acquire an AF adjustment value.

Schematic diagram of an imaging apparatus according to the present embodiment The block diagram which shows the system configuration | structure of the imaging device and lens unit in this embodiment. Schematic diagram showing the configuration of the first focus detection means The figure which shows the ranging point and ranging line of a 1st focus detection means The figure which shows the pixel structure of the 2nd focus detection means in Example 1, and a ranging point and a ranging line The figure which shows the calculation method of AF adjustment value by a 1st adjustment means The figure which shows the calculation method of AF adjustment value by a 2nd adjustment means Flowchart showing AF adjustment value acquisition processing in Embodiment 1 Flow chart showing processing in the first adjustment mode Flowchart showing processing in the second adjustment mode Flowchart showing AF adjustment value acquisition processing in Embodiment 2 The figure which shows the difference of AF adjustment value of Example 3 and Example 1. The figure which shows the ranging point and ranging line of the 2nd focus detection means in Example 4 Flowchart showing AF adjustment value acquisition processing in Embodiment 4

<Example 1>
Hereinafter, an imaging apparatus according to a first embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the lens unit 100 is detachably mounted on the front surface of the camera body 200. The camera body 200 and the lens unit 100 are electrically connected via the mount contact group 104.

  First, the configuration of the lens unit 100 will be described. The photographing lens 101 includes a focus lens for focus adjustment. In FIG. 1, the photographing lens 101 is shown as a single lens, but it may be a lens group composed of a plurality of lenses. Further, the photographing lens 101 may include a zoom lens or a fixed lens for zooming. The diaphragm 105 adjusts the amount of light that enters the camera body 200. The photographic lens 101 and the aperture 105 constitute a photographic optical system.

  The lens control unit 103 performs data communication with the camera body 200 via the mount contact group 104, and controls the position of the photographing lens 101 by controlling the lens driving source 102 based on an instruction from the camera body 200. The lens driving source 102 is a driving source for moving the photographing lens 101 and is configured using a stepping motor or the like.

  Next, the configuration of the camera body 200 will be described. The imaging element 209 (imaging processing means) is configured using a CCD sensor, a CMOS sensor, or the like, photoelectrically converts a subject image formed by a light beam that has passed through the imaging optical system, and outputs an imaging signal. Although details will be described later, the image sensor 209 according to the present exemplary embodiment can generate an image signal used for focus detection by the imaging surface phase difference detection method. The shutter 208 limits the amount of light that enters the image sensor 209.

  The main mirror 201 having a semi-transmissive portion is retracted out of the photographing light beam at the time of photographing, and is obliquely installed in the photographing light beam (in the optical path) at the time of focus detection. FIG. 1 shows a state where the main mirror 201 is inserted into the imaging light beam (mirror down). In addition, the main mirror 201 is provided in a finder optical system including a focus plate 203, a pentaprism 204, and an eyepiece lens 205, with a part of the light beam that has passed through the photographic optical system in a state of being inclined in the photographic light beam. Lead. Further, the light beam reflected by the main mirror 201 enters the photometric unit, and the luminance signal and color difference signal of the subject optical image that has passed through the photographing optical system are detected.

  The sub mirror 202 is configured to be foldable and unfoldable with respect to the main mirror 201 in synchronization with the operation of the main mirror 201. A part of the light beam that has passed through the semi-transmissive portion of the main mirror 201 is reflected downward by the sub-mirror 202 and enters the phase difference type focus detection unit 207 to detect the focus state of the focus lens. The focus detection unit 207 will be described later with reference to FIG.

  A system control unit 210 that controls the entire camera body 200 is configured using a CPU and a RAM that is a storage device. The system control unit 210 performs data communication with the lens control unit 103 via the mount contact group 104 and transmits a driving command for the photographing lens 101.

  A display unit 212 as a display unit displays shooting information and a shot image so that the user can check. The display on the display unit 212 is controlled by the system control unit 210.

  The operation unit 213 is connected to the system control unit 210 and is provided with operation members for operating the camera body 200 such as a power switch and a release button for turning on / off the power of the camera body 200. When these switches and buttons are operated, a signal corresponding to the operation is input to the system control unit 210. The release button includes a release switch SW1 that is turned on by a first stroke operation (half-press operation) of a release button operated by a user, and a release switch SW2 that is turned on by a second stroke operation (full-press operation). It is connected.

  The counter 214 is connected to the system control unit 210 and counts the number of shootings when bracket shooting is performed. The counter value of the counter 214 is reset by the system control unit 210.

  The storage unit 211 such as an EEPROM stores ID information (identification information) unique to the camera body 200, adjustment values of parameters related to shooting, which are adjusted using a reference lens (a shooting lens used during factory adjustment of the camera), and the like. Is remembered. Storage processing in the storage unit 211 such as an EEPROM is performed by the system control unit 210.

  On the other hand, in the lens unit 100, a memory (not shown) that stores performance information such as a focal length and an open aperture value of the lens unit 100 and lens ID (identification) information that is unique information for identifying the lens unit 100. ) Is provided. This memory also stores information received from the system control unit 210 through communication. The performance information and the lens ID information are transmitted from the lens control unit 103 to the system control unit 210 by initial communication when the camera body 200 is mounted. The system control unit 210 stores the received information in the storage unit 211.

  FIG. 2 is a block diagram illustrating a system configuration of the imaging apparatus and the lens unit in the present embodiment. Each function shown in the figure is realized by the cooperation of the hardware and software shown in FIG. 1 under the control of the system control unit 210.

  The image capturing unit 2001 captures an image using the image sensor 209. The first focus detection unit 2002 uses the focus detection unit 207 to detect the defocus amount of the subject by the phase difference detection method. The second focus detection unit 2003 detects the defocus amount of the subject by the phase difference detection method using the focus detection image signal output from the image sensor 209. The lens control unit 2004 controls the driving of the focus lens based on the defocus amount by the system control unit 210 and the lens control unit 103.

  The first adjustment unit 2005 calculates an AF adjustment value for adjusting the focus detection result by the focus detection unit 207 in a first adjustment mode described later. The first adjustment unit 2005 calculates an AF adjustment value from the difference in the defocus amount between the focus position detected by the first focus detection unit 2002 and the focus position selected by the user.

  The second adjustment unit 2006 calculates an AF adjustment value for adjusting the focus detection result of the focus detection unit 207 in a second adjustment mode described later. The second adjustment unit calculates an AF adjustment value from the difference between the defocus amount detected by the first focus detection unit 2002 and the defocus amount detected by the second focus detection unit 2003 at the same position. The storage unit 2007 stores the AF adjustment value calculated by the first adjustment unit 2005 or the second adjustment unit 2006 in the storage unit 211.

  Next, the first focus detection unit 2002 (focus detection unit 207) will be described with reference to FIGS. FIG. 4 is a schematic diagram showing the configuration of the focus detection unit 207.

  FIG. 4 shows a field lens 401 disposed in the vicinity of the planned focal plane, and lenses 402a and 402b of the secondary imaging system composed of two lenses. In addition, a photoelectric conversion element 403 including two line sensor rows 403a and 403b disposed behind and corresponding to the two lenses 402a and 402b of the secondary imaging system, and a diaphragm 404 having two openings 404a and 404b. It is shown. Further, an exit pupil 405 of the photographing lens 101 including two divided areas 405a and 405b is shown.

  In the configuration of FIG. 4, the exit pupil 405 has a small diameter because it projects the diaphragm 404, and the signal extracted from the photoelectric conversion element (line sensor) 403 is a clear signal that is difficult to blur. Therefore, for example, even if the photographing lens 101 is extended to the left in the drawing and a light beam forms an image on the left side of the image sensor 209, the pair of image signals on the photoelectric conversion element 403 is not blurred but in the direction of arrow A. Displace. The focus state (defocus amount) of the photographing lens 101 is detected by detecting the relative displacement amount of the pair of image signals obtained by the photoelectric conversion element 403. That is, once the charge accumulation operation is performed in the focus detection unit 207, the amount and direction to move the focus lens can be obtained. Then, based on the detection result of the defocus amount, the system control unit 210 can perform focus adjustment by controlling the driving of the photographing lens 101 (focus lens). When the photographing lens 101 is retracted to the right in the figure, the pair of image signals on the photoelectric conversion element 403 is displaced in the direction opposite to the direction of the arrow A in the figure.

  FIG. 3 shows a back-projected image of the line sensor (photoelectric conversion element) on the primary imaging plane. In FIG. 3, distance measuring lines 301, 303, and 304 corresponding to the horizontal line sensor are suitable for focus detection of a subject mainly including vertical lines. Further, the distance measuring lines 302, 305, and 306 corresponding to the vertical line sensor are suitable for detecting the focus of a subject mainly including horizontal lines. An oblique line sensor may be further provided. A to E in the figure indicate distance measuring points (focus detection areas). The distance measuring point A is composed of distance measuring lines in the horizontal direction and the vertical direction, and is called a cross eye. Distance measuring points B and C are composed of horizontal distance measuring lines and are called horizontal eyes, and distance measuring points D and E are composed of vertical distance measuring lines and are called vertical eyes. In this embodiment, an AF adjustment value is calculated for the center distance measuring point A, and the same AF adjustment value is reflected on the surrounding distance measurement points B to E.

  The arrangement and number of distance measuring points and distance measuring lines are not limited to the configuration shown in FIG. For example, a plurality of ranging points having cross-type ranging lines may be provided.

  Next, focus detection (hereinafter referred to as imaging plane phase difference AF) of the imaging plane phase difference detection method using the image signal output from the imaging element 209 by the second focus detection unit 2003 will be described with reference to FIG. . FIG. 5A is a schematic diagram illustrating a configuration example of pixels of the image sensor 209 corresponding to the imaging surface phase difference AF. Here, it is assumed that a Bayer array primary color filter is provided.

  In the pixel configuration in FIG. 5A, one pixel is divided into two in the horizontal direction, and two photodiodes A and B (photoelectric conversion elements) are provided. A light beam incident on each pixel is separated by a microlens and received by two photodiodes provided in the pixel, whereby two signals for imaging and AF can be acquired by one pixel. That is, the signals obtained by the two photodiodes A and B (A pixel and B pixel) in the pixel are the two image signals for AF, and the addition signal is the imaging signal. It should be noted that the pair of image signals used in the imaging plane phase difference AF also includes the plurality of A pixels and the plurality of pixels so that the pair of image signals used in the focus detection unit 207 described above is generated by a pair of line sensors having a plurality of pixels. Obtained from the output of the B pixel. Similarly to the first focus detection unit 2002, in the imaging plane phase difference AF, the correlation calculation is performed on the pair of image signals for AF, and the relative position shift amount is detected, thereby detecting the focus of the photographing lens 101. A state (defocus amount) is detected. The pixel pitch of the second focus detection unit 2003 is smaller than the pixel pitch of the line sensor of the first focus detection unit 2002, and more accurate focus detection is possible.

  FIG. 5B is a diagram illustrating a distance measuring line of the second focus detection unit 2003 of the present embodiment. In the present embodiment, as described with reference to FIG. 5A, each pixel used for the imaging plane phase difference AF is divided into two in the horizontal direction. Therefore, unlike the first focus detection unit 2002, the second focus detection unit 2003 has only a horizontal distance measuring line 501. Therefore, the second focus detection unit 2003 of the present embodiment is not suitable for focus detection of a subject mainly including horizontal lines.

  In the second focus detection unit 2003, the distance measuring line 501 can be freely set within the frame 502 excluding the peripheral region. Therefore, the second adjustment means 2006 sets the distance measurement line of the second focus detection means 2003 in accordance with the location where the distance measurement line of the first focus detection means 2002 exists, and compares the respective defocus amounts. Adjustment value can be calculated. In this embodiment, the range in which the focus can be detected by the second focus detection unit 2003 in the region on the screen is described as including the range in which the focus can be detected by the first focus detection unit 2002. However, the present invention is limited to this configuration. Is not to be done. If there is no distance measurement line of the second focus detection means 2003 corresponding to the distance measurement point in the first focus detection means 2002, the first adjustment means 2005 can acquire the AF adjustment value.

  The first adjustment mode executed in the first adjustment unit 2005 will be described with reference to FIG. In the first adjustment mode, a plurality of images are shot while shifting the focus (focus bracket shooting), and the AF adjustment value is calculated based on the focus state of the image selected by the user from the plurality of images. The In FIG. 6, arrows indicate the driving direction and driving amount of the focus lens by the lens control unit 2004. A lens position 605 in the figure indicates a focus position obtained by performing focus detection by the first focus detection unit 2002 before starting focus bracket photographing.

  In the first adjustment mode, the focus lens is moved to the start position from the in-focus position indicated by the lens position 605, and the focus lens is driven by a finer second drive amount starting from that position. The first drive amount is usually determined based on the focus determination width of the focus lens (considered as in-focus if within the range of the width from the focus position). Double is a guide. If the drive amount is too large, the focus change is too coarse, and if it is too small, the focus change is too fine, and it becomes difficult to select one from a plurality of images later. Lens positions 601 to 609 in the drawing represent focus lens positions at which the defocus amount is detected and the photographing operation is performed. That is, the defocus amount detection and photographing operation are performed while moving the focus lens by the second drive amount on both the close side and the infinite side with respect to the in-focus position 605 obtained by performing the focus detection first. Perform a predetermined number of times.

The user selects a desired focus image from the images P _{601 to} P ₆₀₉ captured at the lens positions _{601 to 609} . In the figure, it is assumed that an image P ₆₀₇ photographed at the lens position 607 is selected by the user. The system control unit 210 includes a defocus amount D ₆₀₇ at the lens position of the selected image, it calculates the AF adjustment value based on a difference between the defocus amount D ₆₀₅ at focus position 605. In this embodiment, the AF adjustment value is calculated by converting the defocus amount into a predetermined unit system (for example, a function of Fδ indicating the depth is one unit). The calculated AF adjustment value is stored in the storage unit 211 by the storage unit 2007 as an AF adjustment value in the first adjustment mode. The above is the flow of calculating the AF adjustment value by the first adjustment unit 2005.

Next, the second adjustment mode executed in the second adjustment unit 2006 will be described with reference to FIG. In the second adjustment mode, the lens control unit 2004 first drives the focus lens to the in-focus position 705 based on the result detected by the first focus detection unit 2002 (focus detection unit 207). Then, the defocus amount D ₇₀₅ is calculated by the first focus detection unit 2002, and the defocus amount E ₇₀₅ is calculated by the second focus detection unit 2003. The system control unit 210 calculates an AF adjustment value based on the difference between D ₇₀₅ and E ₇₀₅ . Also in the second adjustment mode, the AF adjustment value is calculated by converting the defocus amount into the predetermined unit system described above. The calculated AF adjustment value is stored in the storage unit 211 by the storage unit 2007 as an AF adjustment value in the second adjustment mode. In the second adjustment mode, since the user does not need to select an image as in the first adjustment mode, the image P ₇₀₅ need not be taken at the in-focus position 705. The above is the flow of calculating the AF adjustment value by the second adjustment unit 2006.

  As described above, the second adjustment unit 2006 is simpler and more efficient than the first adjustment unit 2005. In the first adjustment unit 2005, the focus accuracy of the AF adjustment value depends on the judgment of the user. In addition, when there is a true in-focus position between the two images, an AF adjustment value for accurately focusing cannot be obtained. For this reason, it is desirable to use the second adjustment means 2006 to obtain a highly accurate AF adjustment value.

  However, in order for the second adjustment unit 2006 to obtain a highly accurate AF adjustment value, it is necessary to satisfy the condition that the first focus detection unit 2002 and the second focus detection unit 2003 have the same defocus amount detection direction. As described with reference to FIGS. 4 and 5, in the present embodiment, the first focus detection unit 2002 includes ranging points corresponding to either or both of the horizontal eye and the vertical eye, but the second focus detection unit 2003 includes It has only a horizontal eye. For this reason, when the longitudinal distance measuring point of the first focus detection unit 2002 is used, the AF adjustment value cannot be calculated by the second adjustment unit 2006.

  In this way, it is assumed that the direction in which the first focus detection unit 2002 can detect the defocus amount and the direction in which the second focus detection unit 2003 can detect the defocus amount do not necessarily match. Therefore, in the first embodiment, the first adjustment unit 2005 and the second adjustment unit 2006 are switched according to the shooting conditions as shown in the flowchart of FIG.

  FIG. 8 is a flowchart illustrating AF adjustment value acquisition processing according to the first embodiment. First, in step S801, the defocus amount detection direction (range measurement line direction) of the line sensor corresponding to the distance measurement point of the first focus detection unit 2002 (focus detection unit 207) to be adjusted is determined. In the present embodiment, the AF adjustment value is calculated only for the center distance measuring point (cross eye), but the AF adjustment value may be calculated at a distance measuring point other than the center. In this case, as a method for selecting a distance measuring point for calculating an AF adjustment value from a plurality of distance measuring points, a method for selecting by a user operation, a method for automatic selection by a camera, or the like can be applied. If the defocus amount detection direction is the vertical direction (ranging points D and E in FIG. 3), the process proceeds to step S802. If the defocus amount detection direction is the horizontal direction (ranging points B and C in FIG. 3), the process proceeds to step S803. The distance measuring point A) in FIG. 3 proceeds to step S804.

  When the process proceeds to step S802, since the AF adjustment value cannot be calculated by the second adjustment unit 2006 as described above, the first adjustment mode is executed by the first adjustment unit 2005 to calculate the AF adjustment value. . Details of the first adjustment mode will be described later with reference to FIG.

  On the other hand, if the process proceeds to step S803, the second adjustment unit 2006 executes the second adjustment mode to calculate the AF adjustment value. Details of the second adjustment mode will be described later with reference to FIG.

  When the process proceeds to step S804, processing for selecting a line sensor used for adjustment is performed. In step S804, the system control unit 210 controls the focus detection unit 207 so that the defocus amount is detected by the horizontal and vertical line sensors corresponding to the distance measuring point to be adjusted.

  Based on the defocus amount detected in step S804, in step S805, the system control unit 210 transmits a drive command to the lens control unit 103 to control to drive the focus lens. Of the defocus amounts detected by the line sensors in the horizontal direction and the vertical direction, those detected by the line sensor with high image signal reliability are used for drive control of the focus lens. The evaluation of the reliability of the image signal will be described later in step S807. The processing in steps S804 and S805 is repeated until it is determined in step S806 that the in-focus state is obtained.

  In step S807, the system control unit 210 selects and stores a line sensor with the highest image signal reliability from the focus detection results of the horizontal and vertical line sensors. The reliability of the image signal here is evaluated by a value relating to the contrast of the image signal, for example. In this case, it can be said that the higher the contrast of the image signal, the higher the reliability. As an index of reliability, for example, an S level value disclosed in Japanese Patent Application Laid-Open No. 2007-52072 may be used. The S level value is a value that uses, as parameters, the degree of coincidence of a pair of image signals, the number of edges (correlation change amount), sharpness, and contrast ratio as information about the image signals. By using the photoelectric conversion element selected in step S807 for focus detection at the time of focus bracket photography, which will be described later, an image signal with higher contrast can be obtained, so that the defocus amount can be detected with high accuracy. In addition, since it is easy to determine the edge direction of the subject at the in-focus position, by selecting the line sensor using the image signal in the state determined to be in focus as in this embodiment, the edge direction of the subject is determined. It is possible to select an appropriate line sensor according to the response.

  In step S808, the defocus amount detection direction of the line sensor selected in step S807 is determined. If the selected line sensor is in the vertical direction, the process proceeds to step S809. If the selected line sensor is in the horizontal direction, the process proceeds to step S810. If the process proceeds to step S809, the first adjustment mode is executed to calculate the AF adjustment value. On the other hand, if the process proceeds to step S810, the second adjustment mode is executed to calculate the AF adjustment value.

  When the AF adjustment value is calculated in any of steps S802, S803, S809, and S810, the process proceeds to step S811. In step S811, the storage unit 2007 stores the AF adjustment value in the storage unit 211. In the first embodiment, the AF adjustment value calculated for either the vertical eye or the horizontal eye is stored at the center distance measuring point. The stored AF adjustment value is used to adjust the focus detection result of the phase difference AF detected by the first focus detection unit 2002 (focus detection unit 207) during actual shooting (shooting the recording image). It is done.

  Processing executed in the first adjustment mode will be described with reference to FIG. FIG. 9 is a flowchart illustrating a processing procedure in the first adjustment mode.

  First, in step S <b> 901, the system control unit 210 controls to drive the focus lens to the in-focus position based on the focus detection result by the first focus detection unit 2002. When the process proceeds to step S809 and this flow is executed, the process of step S901 may be omitted because the focus lens is already driven to the in-focus state.

At step S902, the detected defocus amount _{D 0} by the first focus detection unit 2002. Where it detects a plurality of times defocus amount may be the average value as the defocus amount D _0. It becomes the defocus amount D ₀ 0 ideally, but by displacement of the stop position of the change and the focus lens of the subject, there is a possibility that the defocus amount D ₀ does not always become zero.

  In step S903, the system control unit 210 transmits a drive command to the lens control unit 103 to control the focus lens to be driven. Immediately after the start of the first adjustment mode (first image shooting), the focus lens is driven by the above-described first movement amount to the focus lens position (start position) at which the focus bracket shooting operation is started. In the second and subsequent photographing, the focus lens is driven by the second movement amount described above.

In step S904, the defocus amount _Di is detected by the first focus detection unit 2002 at the current focus lens position. Where it detects a plurality of times defocus amount may be the average value as the defocus amount D _i.

In step S905, the system control unit 210 calculates a defocus amount difference T _i from the defocus amounts D ₀ and D _i detected in steps S902 and S904.

In step S906, taking an image _{P i} by the imaging unit 2001. In step S907, the storage unit 2007 stores the image captured by the difference _{T i} and step S906 which is calculated in step S905 in the internal memory in association.

  In step S908, the system control unit 210 determines whether or not the number of shootings has reached the bracket shooting number i (i = 9 in this embodiment). If the number of shootings has reached i times, the process proceeds to step S909, and if the number of shootings has not reached i times, the process returns to step S903.

In step S909, the system control unit 210 controls to display a plurality of images _P 1 to P ₉ taken at step S906 on the display unit 212 waits for the image by the user is selected. If an image is selected, the process proceeds to step S910.

In step S910, it converts the difference T _i which is stored in association with the image selected at step S909 to the AF adjustment value in the manner described above. Although this embodiment and storing by converting the difference T _i of the defocus amount to the AF adjustment value may be stored difference T _i as the adjustment information for calibration. The above is the process flow in the first adjustment mode.

  Next, processing executed in the second adjustment mode will be described with reference to FIG. FIG. 10 is a flowchart showing processing in the second adjustment mode.

  First, in step S1001, the system control unit 210 controls to drive the focus lens to the in-focus position based on the focus detection result by the first focus detection unit 2002. Here, focus detection is performed using a horizontal line sensor. When the process proceeds to step S810 and this flow is executed, the process of step S1001 may be omitted because the focus lens has already been driven to the focused state.

In step S1002, it detects the defocus amount _{D 0} by the first focus detection unit 2002. Where it detects a plurality of times defocus amount may be the average value as the defocus amount D _0. It becomes the defocus amount D ₀ 0 ideally, but by displacement of the stop position of the change and the focus lens of the subject, there is a possibility that the defocus amount D ₀ does not always become zero.

In step S1003, it detects the defocus amount _{E 0} by the second focus detection unit 2003. Where it detects a plurality of times defocus amount may be the average value as the defocus amount E _0.

  In step S1004, it is determined whether or not the first focus detection unit 2002 and the second focus detection unit 2003 have the same defocus amount detection direction (detection range detection line). If the detection directions are the same, the process proceeds to step S1005, and if different, the process proceeds to step S1007. In the present embodiment, since the second focus detection unit 2003 is only the horizontal eye, the branch of step S1004 always proceeds to Yes.

In step S1005, the system control unit 210, from the defocus amount _{D 0} and _{E 0,} which is detected in step S1002 and S1003, and calculates the difference between _{T 0} of the defocus amount. In step S1006, the system control unit 210, the absolute value of the difference _{T 0} of the defocus amount calculated in step S1005 it is determined whether the threshold value Th smaller than. If the absolute value of the defocus amount difference T ₀ is smaller than the threshold value Th, the process proceeds to step S1007. If the absolute value is greater than the threshold value Th, the process proceeds to step S1008.

In step S1007, converting the difference _{T 0} of the defocus amount calculated in step S1005 to the AF adjustment value in the manner described above. In the present embodiment, the defocus amount difference T ₀ is converted into an AF adjustment value and stored. However, the difference T ₀ may be stored as adjustment information for calibration.

On the other hand, if the process proceeds to step S1008, the AF adjustment value is not detectable. Here, if the process proceeds to No in branch of step S1006, that is, when the difference between the defocus amount D ₀ and E ₀ is large, it is estimated detection error of the second focus detection unit 2003 is larger. Therefore, if the AF adjustment value is calculated using the defocus amount E ₀ , there is a possibility that the AF adjustment value includes an error. Therefore, in this embodiment, when the difference between the defocus amount D ₀ and E ₀ is large, and undetectable AF adjustment value. The above is the process flow in the second adjustment mode.

  As described above, in the first embodiment, the first adjustment mode for acquiring the AF adjustment value based on the user's judgment and the first adjustment mode for acquiring the AF adjustment value using the difference between the detection results by the different focus detection means. Two adjustment modes are provided. Then, an appropriate adjustment mode is selected according to the shooting conditions. More specifically, the first adjustment mode and the second adjustment mode are switched according to the detection direction of the defocus amount by the first focus detection unit. Accordingly, the AF adjustment value can be calculated by the first adjustment mode in a scene where the second adjustment mode cannot be used while utilizing the second adjustment mode capable of calculating the AF adjustment value with high accuracy.

<Example 2>
Next, an AF adjustment value acquisition process according to the second embodiment will be described. When it is determined that the AF adjustment value cannot be detected in the second adjustment mode, the process is terminated without storing the AF adjustment value in the first embodiment, but the AF adjustment is performed in the first adjustment mode in the second embodiment. Detect value. Descriptions of parts common to the first embodiment such as the configuration of the camera are omitted.

  FIG. 11 is a flowchart showing an AF adjustment value acquisition process performed in this embodiment, instead of FIG. The processing in steps S1101 to S1111 in FIG. 11 is the same as the processing in steps S801 to S811 in FIG.

  When the second adjustment mode is executed in step S1103, the process proceeds to step S1112, and the system control unit 210 determines whether or not the AF adjustment value cannot be detected (see step S1008 in FIG. 10). If the detection of the AF adjustment value is not impossible, the process proceeds to step S1111 and the calculated AF adjustment value is stored in the storage unit 211. On the other hand, if the AF adjustment value cannot be detected, the process proceeds to step S1102, and the first adjustment mode is executed.

  Similarly, when the second adjustment mode is executed in step S1110, it is determined in step S1113 whether it is determined that the AF adjustment value cannot be detected, and the process is switched according to the result.

  As described above, in this embodiment, even when the AF adjustment value cannot be detected in the second adjustment mode, the AF adjustment value can be detected in the first adjustment mode.

<Example 3>
In the first embodiment, the case where the AF adjustment value calculated at the center distance measuring point and with either the vertical eye or the horizontal eye is stored has been described. On the other hand, in the third embodiment, AF adjustment values calculated for the vertical eye and the horizontal eye can be stored at the center distance measuring point (cross eye).

  FIG. 12 is a table comparing the number of AF adjustment values stored in the storage unit 211 by the storage unit 2007 according to the first embodiment and the third embodiment. In the first embodiment, only one AF adjustment value is stored for the center distance measuring point, but in the third embodiment, AF adjustment values are stored for the number of the distance measurement line directions with respect to the center distance measuring point. That is, if the center distance measuring point is a cross between the vertical eye and the horizontal eye, it is possible to have two AF adjustment values. As the calculation method of the AF adjustment value, the method described in the first embodiment or the second embodiment is used, but it is necessary to calculate the AF adjustment value for each of the vertical eye and the horizontal eye. Therefore, in step S807 or S1107, both the horizontal and vertical line sensors can be selected. If one AF adjustment value is not possible, the other AF adjustment value is stored instead.

  As described above, according to the third embodiment, the lateral focus and the vertical eye respectively have AF adjustment values with respect to the center distance measuring point (cross eye). In addition, the same value as the AF adjustment value calculated at the center distance measuring point is reflected for the surrounding distance measuring points for each detection direction of the distance measuring line.

  In the above description, the AF adjustment value is calculated only at the center distance measuring point. However, the AF adjustment value may also be calculated at each peripheral distance measuring point. In the case where the surrounding distance measuring points are also crossed, the AF adjustment values of the vertical and horizontal eyes may be calculated and stored.

<Example 4>
Next, an AF adjustment value acquisition process according to the fourth embodiment will be described. In the fourth embodiment, the second focus detection unit 2003 can detect the focus both in the horizontal direction and in the vertical direction. Descriptions of parts common to the first embodiment such as the configuration of the camera are omitted.

  FIG. 13 is a diagram illustrating a distance measuring line of the second focus detection unit 2003 of the present embodiment. In the first embodiment, as described with reference to FIG. 5A, the case where the pixels in the image sensor 209 are divided into two in the horizontal direction has been described. However, in this embodiment, the pixels are also divided in the vertical direction. Yes. Therefore, focus detection can be performed in both directions of the distance measuring line 1301 in the horizontal direction and the distance measuring line 1302 in the vertical direction. In this case, the AF adjustment value can be calculated by the second adjustment unit 2006 at any distance measuring point of the first focus detection unit 2002.

FIG. 14 is a flowchart showing an AF adjustment value acquisition process performed in this embodiment, instead of FIG. First, in step S1401, the second adjustment mode by the second adjustment unit 2006 is executed. In the present embodiment, when the distance measurement point of the first focus detection unit 2002 is a cross, the distance measurement line with higher reliability of the image signal detected in the state of moving to the in-focus position in step S1001 is used. detects a defocus amount _{D 0} in step S1002. Also in the second focus detection unit 2003, among the horizontal and vertical directions, by using the distance measurement line of more reliable image signal, detects the defocus amount E ₀ at step S1003. Here, if the directions of the distance measurement lines in steps S1002 and S1003 are different, the process proceeds to No in step 1004.

  In step S1402, the system control unit 210 determines whether or not the AF adjustment value cannot be detected in the second adjustment mode performed in step S1401. If the AF adjustment value cannot be detected, the process proceeds to step S1403, and the first adjustment unit 2005 executes the first adjustment mode. On the other hand, if the AF adjustment value cannot be detected, the process proceeds to step S1404. In step S1404, the storage unit 2007 stores the AF adjustment value calculated in step S1404 or S1403 in the storage unit 211.

  As described above, in the fourth embodiment, the second focus detection unit 2003 can also detect the focus in a plurality of different directions, and more effectively use the second adjustment mode capable of calculating the AF adjustment value with high accuracy. can do.

DESCRIPTION OF SYMBOLS 101 Shooting lens 200 Camera main body 207 Focus detection unit 209 Image sensor 210 System control part 211 Memory | storage part

Claims (11)

An imaging apparatus having an adjustment mode for acquiring an adjustment value used for adjusting a focus detection result for at least one focus detection region,
An imaging processing unit that includes a pixel that generates an image signal used for focus detection in a phase difference detection method, photoelectrically converts a subject image, and captures an image;
First focus detection means for detecting a defocus amount based on an image signal different from the image signal output from the imaging processing means;
Second focus detection means for detecting a defocus amount based on an image signal output from the imaging processing means;
Control means for controlling the position of the focus lens;
Calculating means for calculating the adjustment value used for adjusting the detection result by the first focus detection means;
As the adjustment mode, a first mode for calculating the adjustment value based on a focus state of an image selected by a user from a plurality of images in different focus states, and a detection result by the second focus detection means A second mode for calculating the adjustment value based on
Switching between the first mode and the second mode according to a detection direction of a defocus amount by the first focus detection unit in the focus detection region which is a target for calculating the adjustment value; An imaging device.   In the focus detection area that is the target for calculating the adjustment value, the detection direction of the defocus amount by the first focus detection unit corresponds to the direction in which the defocus amount can be detected by the second focus detection unit. The imaging apparatus according to claim 1, wherein the adjustment value is calculated in the second mode.   In the focus detection area that is the target for calculating the adjustment value, the detection direction of the defocus amount by the first focus detection unit corresponds to the direction in which the defocus amount can be detected by the second focus detection unit. The imaging apparatus according to claim 1, wherein the adjustment value is calculated in the first mode if not.   4. The direction in which the defocus amount can be detected by the first focus detection unit includes a direction in which the defocus amount can be detected by the second focus detection unit. 5. The imaging apparatus of Claim 1.   The first focus detection means can detect defocus amounts in a plurality of different directions with respect to at least one of the focus detection areas, and an index indicating the contrast of the image signal is included in the plurality of different directions. The imaging apparatus according to claim 1, wherein a defocus amount in a higher direction is used for calculating the adjustment value.   6. The adjustment value is calculated in the first mode when it is determined in the second mode that the adjustment value cannot be calculated. 6. The imaging apparatus according to item 1. In the first mode,
The control means controls to move the focus lens to a plurality of different lens positions;
At each lens position of the plurality of lens positions, image capturing by the imaging processing unit and defocus amount detection by the first focus detection unit are performed,
The said calculation means calculates the said adjustment value based on the said defocus amount corresponding to the image selected by the user from the said some image, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. The imaging device described in 1. In the second mode,
The calculation means calculates the adjustment value based on a difference between a first defocus amount detected by the first focus detection means and a second defocus amount detected by the second focus detection means. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus.   In the second mode, the calculation means includes the first defocus amount detected in a state where the focus lens is moved to a focus position based on a detection result of the first focus detection means, and the first defocus amount. The imaging apparatus according to claim 8, wherein the adjustment value is calculated based on a difference between two defocus amounts.   In the second mode, when the difference between the first defocus amount and the second defocus amount is greater than a predetermined threshold, the adjustment value is calculated by switching to the first mode. The imaging apparatus according to any one of claims 1 to 9, wherein the imaging apparatus is characterized. An object having an adjustment mode for acquiring an adjustment value used for adjusting a focus detection result for at least one focus detection area, and a pixel for generating an image signal used for focus detection by a phase difference detection method; A method for controlling an image pickup apparatus having an image pickup processing means for photoelectrically converting an image to pick up an image,
A first focus detection step of detecting a defocus amount based on an image signal different from the image signal output from the imaging processing means;
A second focus detection step of detecting a defocus amount based on an image signal output from the imaging processing means;
A control step for controlling the position of the focus lens;
A calculation step for calculating the adjustment value used for adjustment of the detection result in the first focus detection step;
As the adjustment mode, a first mode for calculating the adjustment value based on a focus state of an image selected by a user from a plurality of images in different focus states, and a detection result by the second focus detection means A second mode for calculating the adjustment value based on
Switching between the first mode and the second mode according to a detection direction of a defocus amount by the first focus detection unit in the focus detection region which is a target for calculating the adjustment value; Control method for imaging apparatus.

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