Imaging device, lens device, control method thereof, and storage medium

Abstract

The present invention relates to an imaging device, a lens device, a control method thereof, and a storage medium. The imaging device includes: an image sensor having a pair of focus detection pixels configured to receive light beams that have passed through different areas of an exit pupil of an imaging optical system; at least one processor; and at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as a focus detection unit. The focus detection unit is configured to detect the focus of the imaging optical system using a pair of focus detection signals generated using output signals from the pair of focus detection pixels. The focus detection unit can detect focus in multiple spatial frequency bands. The focus detection unit obtains a focus detection result to be used in a spatial frequency band corresponding to an amount of aberration of the imaging optical system, the spatial frequency band being included in the multiple spatial frequency bands.

Description

Technical Field

[0001] The present disclosure relates to an imaging device. Background Art

[0002] Phase-difference focus detection (or phase-difference AF) is known as an automatic focus detection (AF) method for imaging equipment. Phase-difference AF is often used in digital still cameras, and some cameras use image sensors as focus detection sensors. For example, Japanese Patent Application Laid-Open ("JP") No. 2014-74851 discloses a method for reducing the effects of noise by detecting focus using a pupil-segmenting method and measuring distance in multiple spatial frequency bands.

[0003] Since phase-difference AF uses optical images to detect focus, aberrations generated in the optical system that forms the optical images may cause errors in the results of focus detection (hereinafter, also referred to as focus detection results). Japanese Patent Application Laid-Open No. 5966426 discloses a method for correcting focus detection errors (focus detection errors) caused by the inconsistency of the shapes of a pair of optical images formed by a pair of focus detection beams in a focused state due to aberrations of the optical system.

[0004] As a method for changing the degree of soft focus of a lens, Japanese Patent Application Laid-Open No. 4878978 discloses a method for storing images at multiple focus levels and acquiring an image with a desired degree of soft focus through image processing. Furthermore, as a method for acquiring images under multiple imaging conditions, Japanese Patent Application Laid-Open No. 08-029828 discloses a camera capable of performing bracketing by setting the number of times to capture images under multiple types of imaging conditions (the number of times to capture images).

[0005] As a method for obtaining better focus detection accuracy, Japanese Patent Laid-Open No. 5857547 discloses a method of correcting a focus detection error by multiplying a focus detection amount by a correction coefficient.

[0006] However, in phase-difference AF, aberrations can make it difficult to correct focus detection errors. For example, when using a lens called a soft focus lens that intentionally generates large aberrations, the focus detection error is large and varies depending on the amount of blur, making it difficult to correct the focus detection error.

[0007] The method disclosed in Japanese Patent Application Laid-Open No. 4878978 acquires an image with a desired degree of soft focus by combining images. Therefore, the blur caused by the distance to the subject, as in an image obtained using an actual soft focus lens, cannot be reproduced, and it is difficult to acquire an image with a natural degree of soft focus. Furthermore, acquiring an image with a desired degree of soft focus requires capturing images at multiple focus levels and performing image processing, which results in a heavy processing load.

[0008] Japanese Patent Laid-Open No. 08-029828 discloses that a user can select a desired image from a plurality of images captured by bracket imaging, but does not describe a change in the degree of soft focus.

[0009] Japanese Patent Laid-Open No. 5857547 does not describe a method for correcting a defocus amount obtained by detecting a focus in a case where the aberration amount of the optical system is large or the aberration amount is variable. Summary of the Invention

[0010] The present disclosure provides an imaging apparatus and the like that can obtain good focus detection results even when detecting focus using an optical system with large aberrations. The present disclosure also provides an imaging apparatus and the like that can generate an image with a degree of soft focus desired by the user.

[0011] According to one aspect of an embodiment of the present disclosure, an imaging device includes: an image sensor including a pair of focus detection pixels configured to receive light beams that have passed through different areas in an exit pupil of an imaging optical system; at least one processor; and at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as: a focus detection unit configured to detect the focus of the imaging optical system by using a pair of focus detection signals generated using output signals from the pair of focus detection pixels. The focus detection unit is capable of detecting the focus in a plurality of spatial frequency bands. The focus detection unit acquires a focus detection result to be used in a spatial frequency band corresponding to an amount of aberration of the imaging optical system, the spatial frequency band being included in the plurality of spatial frequency bands.

[0012] According to one aspect of the embodiment, a lens device is detachably attached to the above-described imaging device and includes an imaging optical system. The lens device includes: at least one processor; and at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as: a storage unit configured to store (a) information related to an amount of aberration of the imaging optical system or (b) information related to a spatial frequency band for detecting focus, the spatial frequency band corresponding to the amount of aberration; and a notification unit configured to notify the imaging device of the information.

[0013] According to one aspect of the embodiment, a lens device is detachably attached to an imaging device. The lens device includes: an operating member configured to receive a user operation; an optical member configured to change aberration based on the operation of the operating member; at least one processor; and at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as a communication control unit configured to communicate with the imaging device. The communication control unit transmits information indicating that the lens device includes an optical member configured to change the aberration to the imaging device. When the user operates the operating member, the communication control unit transmits information corresponding to the amount of aberration changed based on the operation.

[0014] According to one aspect of the embodiment, an imaging device includes: an image sensor configured to capture an image by receiving a light beam from an imaging optical system and including a pair of focus detection pixels configured to receive light beams that have passed through different areas in an exit pupil of the imaging optical system; at least one processor; and at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as a focus detection unit configured to detect the focus of the imaging optical system by using a pair of focus detection signals generated using output signals from the pair of focus detection pixels. The imaging optical system is capable of varying an amount of aberration. The at least one processor further functions as a control unit configured to control focusing of the imaging optical system based on the focus detection result each time the amount of aberration is varied, and to capture an image.

[0015] According to one aspect of the embodiment, an imaging device includes: an image sensor including a pair of focus detection pixels, the pair of focus detection pixels being configured to receive light beams that have passed through different areas in an exit pupil of an imaging optical system; at least one processor; and at least one memory coupled to the at least one processor and storing instructions, the instructions, when executed by the at least one processor, causing the at least one processor to function as: a focus detection unit configured to detect the focus of the imaging optical system by using a pair of focus detection signals, the pair of focus detection signals being generated by using output signals from the pair of focus detection pixels; and a control unit configured to obtain correction information corresponding to the aberration amount of the imaging optical system, and to correct the focus detection result using the correction information.

[0016] A control method for the above-mentioned camera device and lens device, and a storage medium storing a computer program for enabling a computer to execute the control method, also constitute other aspects of the embodiment.

[0017] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a block diagram showing the configuration of an image pickup apparatus according to a first embodiment of the present disclosure.

[0019] Figure 2 is a diagram showing a pixel array of an image sensor according to the first embodiment.

[0020] Figure 3A and 3B 1 and 2 are a plan view and a cross-sectional view each showing a pixel according to the first embodiment.

[0021] Figure 4 is a diagram illustrating pixels and pupil division according to the first embodiment.

[0022] Figure 5 is a diagram illustrating an image sensor and pupil division according to the first embodiment.

[0023] Figure 6 : is a graph showing the relationship between the defocus amount and the image shift amount of the first focus detection signal and the second focus detection signal according to the first embodiment.

[0024] Figure 7 : is a flowchart showing the focus detection process and the image capturing process according to the first embodiment.

[0025] Figure 8 is a diagram showing spatial frequency bands used for focus detection according to the first embodiment.

[0026] Figure 9 is a diagram showing a defocus curve in a conventional imaging optical system.

[0027] Figure 10 is a diagram showing a defocus curve in an imaging optical system having large aberrations.

[0028] Figure 11 is a flowchart showing the frequency band selection process according to the first embodiment.

[0029] Figure 12 is a diagram showing a comparative example of the LSF according to the first embodiment.

[0030] Figure 13 is a flowchart illustrating processing according to the third embodiment.

[0031] Figure 14A and 14B is a diagram showing a soft focus lens according to a third embodiment.

[0032] Figures 15A to 15E : are diagrams showing captured images acquired by using the aberration bracketing imaging function according to the third embodiment.

[0033] Figure 16 is a diagram showing the configuration of an image pickup apparatus according to a third embodiment.

[0034] Figure 17 is a flowchart illustrating focus detection processing according to the fourth embodiment.

[0035] Figure 18 is a flowchart illustrating correction coefficient calculation processing according to the fourth embodiment.

[0036] Figures 19A to 19C is a diagram showing correction coefficients according to the fourth embodiment. DETAILED DESCRIPTION

[0037] Referring now to the drawings, a description will be given of embodiments according to the present invention.

[0038] First embodiment

[0039] Figure 1 The structure of an image pickup apparatus (hereinafter referred to as a camera) according to the first embodiment of the present disclosure is shown. The camera includes an imaging optical system including a first lens unit 101, an aperture shutter 102, a second lens unit 103, and a third lens unit 105, arranged in this order from the subject side. The imaging optical system may be integrally provided with a camera body including an image sensor described later, or may be provided with a lens device that is an interchangeable lens that can be detachably attached to the camera body.

[0040] During magnification change (i.e., zooming), the first lens unit 101 moves in the optical axis direction, in which the optical axis of the imaging optical system extends. The aperture shutter 102 has an aperture function for adjusting the amount of light by changing the aperture diameter, and has a shutter function for controlling the exposure time in still image shooting. The second lens unit 103 moves integrally with the aperture shutter 102 in the optical axis direction during magnification change. The third lens unit 105 moves along the optical axis direction during focusing. The optical low-pass filter 106 is an optical element for reducing false colors and moiré. The image sensor 107 includes a two-dimensional CMOS (complementary metal oxide semiconductor) sensor and peripheral circuits, and is provided on the image plane of the imaging optical system.

[0041] The zoom actuator 111 drives the first lens unit 101 and the second lens unit 103 in the optical axis direction by rotating a cam barrel (not shown) around the optical axis during magnification variation. The aperture shutter actuator 112 drives the aperture shutter 102. The focus actuator 114 drives the third lens unit 105 in the optical axis direction during focusing.

[0042] The electronic flash 115 emits light to illuminate the subject. The AF flash unit 119 emits AF auxiliary light onto the subject, which forms a mask image with a predetermined aperture pattern to improve focus detection capability for shaded or low-contrast subjects during AF (auto focus).

[0043] The camera CPU 121 is a computer for controlling the entire camera. It controls the driving of various circuits in the camera according to a program, and controls operations such as AF, imaging, image processing, and recording. The camera CPU 121 stores in its internal memory the correction value calculation coefficients required for AF using the output signal from the image sensor 107. A plurality of correction value calculation coefficients are prepared for combinations of the focus state corresponding to the position of the third lens unit 105, the zoom state corresponding to the positions of the first and second lens units 101 and 103, the aperture value (i.e., F-number) of the imaging optical system, and the set pupil distance and pixel size of the image sensor 107. When performing AF, the camera CPU 121 calculates correction values based on the image height on the image sensor 107 and the correction value calculation coefficients corresponding to the combination of the focus state, zoom state, F-number, set pupil distance, and pixel size.

[0044] If the imaging optical system is provided in an interchangeable lens, a memory for storing correction value calculation coefficients can be provided in the interchangeable lens, and when AF is performed, correction values can be calculated by using the correction value calculation coefficients obtained by the camera body from the interchangeable lens.

[0045] The electronic flash control circuit 122 controls the emission of the electronic flash 115 in synchronization with the image pickup operation. The auxiliary light drive circuit 123 controls the emission of the AF flash unit 116 in synchronization with the focus detection operation for AF. The image sensor drive circuit 124 controls the image pickup or photoelectric conversion operation of the image sensor 107, performs A / D conversion on the output signal from the image sensor 107, and transmits the output signal to the camera CPU 121. The image processing circuit 125 generates image data by performing image processing such as gamma conversion and color interpolation on the output signal after A / D conversion (which will also be referred to as an image pickup signal), and performs compression processing such as JPEG compression on the image data.

[0046] The focus drive circuit 126 drives the third lens unit 105 by controlling the focus actuator 114 based on a focus instruction from the camera CPU 121, which is based on the focus detection result. The aperture shutter drive circuit 128 drives the aperture shutter 102 by controlling the aperture shutter actuator 112 based on an aperture shutter instruction from the camera CPU 121, which has performed light metering using an imaging signal. The zoom drive circuit 129 drives the first lens unit 101 and the second lens unit 103 by controlling the zoom actuator 111 based on a zoom instruction from the camera CPU 121, which has detected a user's zoom operation.

[0047] The display 131 includes a display device such as an LCD, and displays various information such as the camera shooting mode, a preview image before shooting, an image to be stored after shooting, a focus detection area as an AF frame, and a focus state. The operation switch group 132 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, and a shooting mode selection switch. The flash memory 133 can be detachably attached to the camera and stores images to be recorded.

[0048] Figure 2 FIG. 1 shows a portion of a pixel array of the image sensor 107 . The image sensor 107 has a plurality of imaging pixels 200 . Figure 2 4 columns × 4 rows of imaging pixels 200 are shown. The 2 columns × 2 rows of imaging pixels 200 include an imaging pixel 200R located at the upper left with R (red) spectral sensitivity, imaging pixels 200G located at the upper right and lower left each with G (green) spectral sensitivity, and an imaging pixel 200B located at the lower right with B (blue) spectral sensitivity. Each imaging pixel 200 includes a pair of focus detection pixels divided in the x direction, and includes a first focus detection pixel 201 and a second focus detection pixel 202. The image sensor 107 includes, on an imaging surface also referred to as a light receiving surface, Figure 2 The illustrated plurality of imaging pixels of 4 columns×4 rows (ie, focus detection pixels of 8 columns×4 rows) enables acquisition of imaging signals and focus detection signals.

[0049] The camera CPU 121, which serves as a focus detection unit and control unit, detects the focus of the imaging optical system using a focus detection signal from the image sensor 107. The camera CPU 121 then controls the focus by controlling the drive of the third lens unit 105 based on the defocus amount determined as a result of the focus detection. In this manner, imaging plane phase difference AF is performed.

[0050] Figure 3A One imaging pixel 200G is shown as viewed from the light receiving surface side (+z side) of the image sensor 107, and Figure 3B Shown is the -y side view. Figure 3A Pixel structure in the cross section at line aa in .

[0051] like Figure 3B As shown, the imaging pixel 200G includes pixels divided into N pixels in the x direction. H The photoelectric converters 301 and 302 (split into two) correspond to Figure 2 The first focus detection pixel 201 and the second focus detection pixel 202 are shown. The photoelectric converters 301 and 302 can be divided into N pixels in the y direction. V The imaging pixel 200G is formed by a microlens 305 for collecting light entering the photoelectric converters 301 and 302. The photoelectric converters 301 and 302 may be PIN photodiodes in which each intrinsic layer is sandwiched between a p-type layer and an n-type layer, or may be pn junction photodiodes in which each intrinsic layer is omitted.

[0052] A color filter 306 for G is formed between the microlens 305 and the photoelectric converters 301 and 302. In the imaging pixels 200R and 200B, color filters for R and B are formed, respectively. Color filters for colors other than R, G, and B may be provided, or the color filters may be omitted.

[0053] The light entering the imaging pixel 200G is collected by the microlens 305, separated by the color filter 306, and then received by the photoelectric converters 301 and 302. In the photoelectric converters 301 and 302, electron-hole pairs are generated corresponding to the amount of light received, and after these pairs are separated by the depletion layer, the negatively charged electrons accumulate in the n-type layer. On the other hand, the holes are discharged to the outside of the image sensor 107 through the p-type layer connected to the constant voltage source (not shown). The electrons stored in the n-type layer of the photoelectric converters 301 and 302 are transferred to the electrostatic capacitor (FD) via the transfer gate and converted into a voltage signal.

[0054] Figure 4 Show Figure 3B The relationship between the pixel structure shown and the division of the exit pupil of the imaging optical system (also referred to as pupil division) is shown. Figure 4 In the pixel structure, the x-axis and y-axis are relative to Figure 3B The inversion is performed so that the coordinate axes of the pixel structure correspond to the coordinate axes of the portion of the pupil plane.

[0055] The first partial pupil region 501 is a region in the exit pupil region 500 through which light received by the photoelectric converter 301 (first focus detection pixel 201) passes. The microlens 305 and the light-receiving surface of the photoelectric converter 301, whose center of gravity is decentered in the −x direction, are generally in a conjugate relationship. The center of gravity of the first partial pupil region 501 is decentered toward the +X side on the partial pupil surface. The second partial pupil region 502 is a region in the exit pupil region 500 through which light received by the photoelectric converter 302 (second focus detection pixel 202) passes. The microlens 305 and the light-receiving surface of the photoelectric converter 302, whose center of gravity is decentered in the +x direction, are generally in a conjugate relationship. The center of gravity of the second partial pupil region 502 is decentered toward the −X side on the partial pupil surface. Light passing through the exit pupil region 500 can be received by the entire imaging pixel 200G, including the photoelectric converters 301 and 302.

[0056] Since pupil division is performed by using the microlens 305 provided for each imaging pixel of the image sensor 107, the imaging plane phase difference AF is affected by diffraction. Figure 4 In the example, the distance from each light-receiving surface of the photoelectric converter to each partial pupil surface (pupil distance) is tens of millimeters, while the diameter of the microlens 305 is several μm. Therefore, the f-number of the microlens 305 is tens of thousands, and diffraction blurring of the order of tens of millimeters occurs. Consequently, the optical image formed on the light-receiving surface of the photoelectric converter is not a sharp image of the exit pupil region or the partial pupil region, but rather an image having an intensity distribution corresponding to the light reception ratio, which corresponds to the light incident angle.

[0057] Figure 5 Light beams entering image sensor 107 upon pupil division are shown. Light beams having passed through first partial pupil area 501 and second partial pupil area 502 enter corresponding photoelectric converters 301 and 302 in image sensor 107 at different angles, respectively.

[0058] The image sensor 107 in this embodiment includes a first focus detection pixel 201 (photoelectric converter 301) that receives a light beam that has passed through the first partial pupil area 501 of the imaging optical system, and a second focus detection pixel 202 (photoelectric converter 302) that receives a light beam that has passed through the second partial pupil area 502. The image sensor 107 also includes an imaging pixel 200 that receives a light beam that has passed through the exit pupil area 500 including the first partial pupil area 501 and the second partial pupil area 502. In this embodiment, each imaging pixel includes the first focus detection pixel 201 and the second focus detection pixel 202, but the imaging pixel and the first focus detection pixel and the second focus detection pixel may be provided as different pixels.

[0059] In this embodiment, the output signals of the corresponding first focus detection pixels 201 of the plurality of imaging pixels 200 are collected to generate a first focus detection signal, and the output signals of the corresponding second focus detection pixels 202 of the plurality of imaging pixels 200 are collected to generate a second focus detection signal. The camera CPU 121 uses a pair of the first focus detection signal and the second focus detection signal to detect focus during imaging plane phase difference AF. The camera CPU 121 adds the output signals of the first focus detection pixel 201 and the second focus detection pixel 202 from each imaging pixel 200 and generates an imaging signal with a resolution of N effective pixels.

[0060] Next, we will refer to Figure 6 The relationship between the phase difference between the first and second focus detection signals (i.e., the image shift amount) and the defocus amount of the subject image is described. In this figure, light beams passing through the first and second partial pupil areas 501 and 502 of the imaging optical system from the subject planes 801 and 802 reach the imaging plane 800 of the image sensor 107.

[0061] The defocus amount d is the distance from the imaging position of the subject image to the imaging surface 800. The front focus state of the imaging position on the subject side of the imaging surface 800 is represented by a negative defocus amount (d<0), and the back focus state of the imaging position on the opposite side of the subject side of the imaging surface 800 is represented by a positive defocus amount (d>0). The focus state of the imaging position on the imaging surface 800 is represented by d=0. The figure shows the focus state of the subject surface 801 and the front focus state of the subject surface 802. In the following description, the front focus state (d<0) and the back focus state (d>0) are collectively referred to as the defocus state (|d|>0).

[0062] In the front focus state, the light beams from the object surface 802 that have passed through the first and second partial pupil areas 501 and 502 are converged once and then expanded to widths Γ1 and Γ2 centered on the centers of gravity G1 and G2 of the light beams, forming a blurred image on the imaging surface 800. The first and second focus detection pixels 201 and 202 of the image sensor 107, which generate first and second focus detection signals, receive the blurred image. The first and second focus detection signals indicate the blurred image of the object surface 802, which has expanded to blur widths Γ1 and Γ2 centered on the centers of gravity G1 and G2 on the imaging surface 800. The blur widths Γ1 and Γ2 increase approximately proportionally with the increase in the magnitude |d| of the defocus amount d. The magnitude |p| of the image shift amount p, which is the difference between the positions of the centers of gravity G1 and G2 of the first and second focus detection signals, also increases approximately proportionally with the increase in |d|. In the rear focus state, the image shift direction of the first focus detection signal and the second focus detection signal is opposite to that in the front focus state, but other details are the same as those in the front focus state.

[0063] Therefore, the defocus amount d can be calculated by using the image shift amount p and a predetermined conversion coefficient K for converting the image shift amount p into the defocus amount d.

[0064] Figure 7 The flowchart in FIG. 1 shows the focus detection processing in this embodiment. The camera CPU 121 executes this processing according to a computer program. Here, the Y signal obtained by adding the first and second focus detection signals of the four imaging pixels of G, R, B, and G is used as the first and second focus detection signals.

[0065] In step S10, the camera CPU 121 generates a first focus detection signal (also referred to as an A image) from the output signal of the first focus detection pixel in the focus detection area of the image sensor 107, and generates a second focus detection signal (also referred to as a B image) from the output signal of the second focus detection pixel in the same focus detection area.

[0066] Next, in step S20, the camera CPU 121 performs addition processing in the column direction to reduce the amount of signal data in the first focus detection signal and the second focus detection signal. The camera CPU 121 further performs addition processing on the G, R, B, and G focus detection signals to generate a Y signal. These two addition processes are collectively referred to as pixel addition processing. When two pixels are added together, the pixel spacing is doubled, so the Nyquist frequency is reduced to half the Nyquist frequency when the pixels are not added together. When three pixels are added together, the pixel spacing is tripled, so the Nyquist frequency is reduced to one-third the Nyquist frequency when the pixels are not added together.

[0067] Next, in step S30 , the camera CPU 121 performs shading correction processing, which is optical correction processing, on the first detection signal and the second detection signal for making the intensities of the first focus detection signal and the second focus detection signal consistent.

[0068] Next, in step S40, the camera CPU 121 performs bandpass filtering processing at a specific passband on the first and second focus detection signals to improve the correlation (i.e., the degree of signal consistency) between the first and second focus detection signals and improve focus detection accuracy. For example, the bandpass filtering processing may be a differential filtering process such as {1, 4, 4, 4, 0, -4, -4, -4, -1}, which removes DC components and extracts edges, or an additive filtering process such as {1, 2, 1}, which reduces high-frequency noise components.

[0069] Next, in step S50, the camera CPU 121 performs offset processing, which offsets the first focus detection signal and the second focus detection signal after bandpass filtering relative to the pupil division direction, and calculates a correlation amount indicating the degree of consistency between these first focus detection signals and the second focus detection signal.

[0070] Assume that A(k) represents the kth first focus detection signal after bandpass filtering, B(k) represents the kth second focus detection signal after bandpass filtering, and W represents the range corresponding to the focus detection area number k. When s represents the offset amount generated by the offset processing, and Γ represents the offset range of the offset amount s, the correlation amount COR is calculated by equation (1).

[0071] COR(s)=Σ k∈W |A(k)-B(ks)|, s∈Γ (1)

[0072] Through the offset processing of the offset amount s, an offset subtraction signal is generated by subtracting the k-th first focus detection signal A(k) from the (ks)-th second focus detection signal B(ks). The correlation amount COR(s) is calculated by calculating the absolute value of the generated offset subtraction signal and adding the number k within the range W corresponding to the focus detection area. If necessary, the correlation amounts calculated for each row can be added for each offset amount over multiple rows.

[0073] Next, in step S60, the camera CPU 121 calculates the real value of the offset s at which the correlation value COR(s) takes a minimum value using sub-pixel calculation, and sets this as the image offset p. The camera CPU 121 calculates the defocus amount (Def) d by multiplying the image offset p by the conversion coefficient k. In this way, the defocus amount is detected.

[0074] In this embodiment, the defocus amount is detected using multiple (here, three) spatial frequency bands of varying levels. The spatial frequency bands are determined based on the number of pixels added in step S20 and the bandpass filtering process in step S40. The higher the number of added pixels and the lower the transmission band in the bandpass filtering process, the lower the spatial frequency band in which the defocus amount is detected. Figure 8 The spatial frequency bands are shown for levels 1, 2, and 3. The spatial frequency band for level 1 is the highest, and the spatial frequency band for level 3 is the lowest.

[0075] The number of spatial frequency bands is not limited to three, and may be another number. Furthermore, it is not necessary to detect the defocus amount simultaneously in a plurality of spatial frequency bands.

[0076] The focus detection accuracy in phase difference AF is represented by a defocus curve. Figure 9 This figure shows an example of a general defocus curve based on optical calculation results. The solid, dashed, and thin dashed lines indicate the results of defocus detection in the spatial frequency bands of levels 1, 2, and 3. The horizontal axis represents the correct defocus amount, and the vertical axis represents the detected defocus amount. Ideally, a detection error of zero occurs when the values on the horizontal and vertical axes are always equal (i.e., the values represent a straight line at a 45° angle relative to the vertical and horizontal axes).

[0077] exist Figure 9 In the image, the defocus amount results for the three spatial frequency bands vary in areas with large defocus, but are generally consistent with a 45° straight line. Near the focused state where the defocus amount is zero, the detection error is small in all spatial frequency bands from levels 1 to 3. Generally, to reduce variation in detection results due to noise, defocus amount results in spatial frequency bands as high as possible are used for the final focus determination.

[0078] Figure 10This figure shows an example of a defocus curve based on optical calculation results for an imaging optical system with large spherical aberration, one of various aberrations. In the highest spatial frequency band of level 1, the defocus curve deviates significantly from a 45° straight line, indicating a large detection error. Furthermore, the defocus curve has a curved shape, indicating that the detection error varies depending on the defocus amount. In levels 2 and 3, the lower the spatial frequency band, the closer the defocus curve becomes to a straight line, meaning the detection error decreases.

[0079] Generally speaking, even in a near-focus state, the image formed by an imaging optical system exhibiting significant spherical aberration is blurred, and even with increasing defocus, the increase in blur is minimal. When the spatial frequency band is high, the edges of line images with small variations due to defocus are detected, while when the spatial frequency band is low, variations across the entire image are detected. Therefore, in an imaging optical system in which spherical aberration increases as the spatial frequency band decreases, good defocus detection results can be achieved.

[0080] Figure 12 The LSF (line image) in this embodiment is shown. The first focus detection signal is represented by LSF_A, and the second focus detection signal is represented by LSF_B. Def0 indicates a focused state, and Def- and Def+ indicate states where blur occurs on the front focus side and the back focus side, respectively, with the blur amount being the same in Def- and Def+. Figure 9 In the imaging optical system with small aberrations shown, LSF_A and LSF_B are roughly aligned in the focused state, and in Def- and Def+, the positions of LSF_A and LSF_B are switched, but the distance between LSF_A and LSF_B is almost the same. The LSF of the imaging signal is obtained by adding LSF_A and LSF_B.

[0081] On the other hand, when Figure 10 In an imaging optical system with large aberrations, the distortion and asymmetry of LSF_A and LSF_B are significant, and the shapes of LSF_A and LSF_B are inconsistent even in the focused state, resulting in large detection errors. In Def-, the distance between LSF_A and LSF_B is correct for small aberrations, but smaller for large aberrations. In Def+, the distance between LSF_A and LSF_B is correct for small aberrations, but larger for large aberrations.

[0082] As described above, in the case of large aberration, since deformation and asymmetry of the LSF occur, the detection error is large in the high-frequency band where the edge is detected, and the amount of the detection error varies depending on the defocus amount.

[0083] In this embodiment, in order to obtain good focus detection accuracy even when using an imaging optical system in which large aberrations occur, the defocus amount detected in a spatial frequency band corresponding to information on the aberration amount of the imaging optical system is used, which is included in a plurality of spatial frequency bands.

[0084] In the following description, the imaging optical system is provided on the interchangeable lens, and a description will be given of a case where the interchangeable lens is a soft focus lens capable of changing or variably setting the amount of spherical aberration of the imaging optical system. The interchangeable lens in this case includes Figure 1 The lens CPU 151 in the brackets in FIG. The lens CPU 151 can communicate with the camera CPU 121 as a computer, and controls the focus drive circuit 126, the aperture shutter drive circuit 128, and the zoom drive circuit 129 provided in the interchangeable lens according to the instructions from the camera CPU 121. Figure 1 The lens memory 152, which is a storage unit shown in parentheses in FIG, stores various lens information such as the amount of spherical aberration of the imaging optical system that can be variably set. The lens CPU 151, which serves as a notification unit, can notify the camera body (camera CPU 121) of the information on the variably set amount of spherical aberration via communication.

[0085] Figure 11 The flowchart of FIG1 shows a band selection process (control method) executed according to a computer program by the camera CPU 121. In step S110, when the lens CPU 151 transmits or notifies the camera of information on the aberration amount of the imaging optical system (which will be referred to as aberration amount information), the camera CPU 121 receives the aberration amount information in step S120.

[0086] The aberration amount information may be information indicating the actual amount of aberration or an index indicating the magnitude of the aberration amount. The aberration amount information may be information indicating the magnitude of the wavefront aberration or may be information indicating the magnitude of the aberration amount in binary. If the camera CPU 121 recognizes that the interchangeable lens is a soft focus lens using identification information such as a lens ID, the aberration setting value of the soft focus lens can be acquired as the aberration amount information.

[0087] Next, in step S130, the camera CPU 121 determines whether the aberration amount indicated by the aberration amount information is small, medium, or large. If the aberration amount is small, the process proceeds to step S140, and the camera CPU 121 selects a defocus amount in a spatial frequency range of one level for AF. If the aberration amount is large, the process proceeds to step S141, and the camera CPU 121 selects a defocus amount in a spatial frequency range of three levels for AF. If the aberration amount is medium, the process proceeds to step S142, and the camera CPU 121 selects a defocus amount in a spatial frequency range of two levels for AF.

[0088] That is, the camera CPU 121 detects the defocus amount used for AF in a spatial frequency band corresponding to the aberration amount.

[0089] While the imaging optical system has been described as a soft focus lens, the lens does not need to be a variable aberration lens, such as a soft focus lens, as long as the imaging optical system generates large aberrations. Even when aberrations are set to large, a high F-number reduces aberrations. Therefore, the spatial frequency band selected for AF can be changed according to the F-number. When the F-number is high, information indicating a low aberration amount can be transmitted from the soft focus lens to the camera body via communication.

[0090] Second embodiment

[0091] Next, a second embodiment of the present disclosure will be described. In this embodiment, as in the first embodiment, the camera CPU 121 detects the defocus amount in the spatial frequency bands of levels 1, 2, and 3.

[0092] On the other hand, in interchangeable lenses, Figure 1 The memory 152 shown stores flags Flg1, Flg2, and Flg3, which are information related to the spatial frequency band used for focus detection. These flags correspond to the spatial frequency bands of levels 1, 2, and 3, respectively. The lens CPU 151 reads flags corresponding to the magnitude of the variably set aberration amount of the imaging optical system (e.g., flags indicating large, medium, and small) and flags indicating the numerical values corresponding to the aberration amounts from the memory 152 and notifies the camera CPU 121. Notified of the flags, the camera CPU 121 performs AF using the defocus amount in the spatial frequency band of the level corresponding to the flags.

[0093] Specifically, when the camera CPU 121 is notified of Flg1, the camera CPU 121 performs AF using the defocus amount in the spatial frequency band of level 1, and when the camera CPU 121 is notified of Flg2, the camera CPU 121 performs AF using the defocus amount in the spatial frequency band of level 2. When the camera CPU 121 is notified of Flg3, the camera CPU 121 performs AF using the defocus amount in the spatial frequency band of level 3.

[0094] The camera CPU 121 and the lens CPU 151 execute the above-described processing according to computer programs.

[0095] The lens CPU 151 may notify the camera CPU 121 of a value of the spatial frequency band (e.g., 10 lines / mm) as information related to the spatial frequency band used for focus detection, instead of a flag indicating the spatial frequency band used for focus detection. In this case, the camera CPU 121 performs AF using a defocus amount that matches this value.

[0096] According to the various embodiments described above, even when detecting focus using an imaging optical system that exhibits significant aberrations (that is, regardless of the amount of aberration), excellent focus detection results can be obtained. In the various examples described above, the focus detection results were used for AF, but the focus detection results can also be used to measure the distance to the subject. In this case, excellent distance measurement results can be obtained.

[0097] The focus detection method described in each of the above embodiments is not limited to the above-mentioned lens-interchangeable cameras and lens-integrated cameras, but can also be applied to various devices such as video cameras, and mobile phones, personal computers, and game consoles each equipped with a camera.

[0098] A detailed description of the structure of a lens device serving as an interchangeable lens will be provided as a variation of the above-described embodiment. The lens device includes an optical component configured to vary aberrations. The optical component can achieve a so-called soft focus effect through aberrations. When a user operates an operating member (not shown) provided on the lens device, the optical component is driven, and the degree of the soft focus effect changes. The lens device includes a communication control unit (not shown) configured to communicate via contacts provided in the lens device and the camera mount.

[0099] When the camera is powered on and power is supplied to the lens device, the camera and lens device engage in initial communication to exchange attribute information. During this initial communication, the lens device transmits information to the camera indicating that the lens device includes an optical component configured to change aberrations, or information indicating that the lens device is capable of changing aberrations. This enables communication between the lens device and the camera based on changes in aberrations, as well as processing by the camera based on changes in aberrations, as described in the above embodiments. When the user operates the operating component, the lens device transmits information to the camera corresponding to the amount of aberration changed in response to that operation. The zeros in this information represent the flags described in the above embodiments.

[0100] Third embodiment

[0101] Next, a third embodiment of the present disclosure will be described. In the third embodiment, bracket imaging is performed while changing the aberration amount as the aberration state of the imaging optical system, so that the user can select a captured image of a desired aberration amount, that is, a desired degree of soft focus.

[0102] Figure 16 The structure of the camera in this embodiment is shown in FIG. Figure 1 The same reference numerals as in Figure 1 The components of the camera shown in FIG. 1 are the same components, and their description will be omitted. Also in this embodiment, the imaging optical system can be provided on the interchangeable lens, but Figure 16 Omitted Figure 1 The lens CPU 151 and lens memory 152 are shown.

[0103] In this embodiment, a soft focus effect is achieved by moving the first lens unit 101 and the second lens unit 103 in the optical axis direction. A soft focus drive circuit 129 ′ drives the first lens unit 101 and the second lens unit 103 by controlling a soft focus actuator 111 ′ based on a soft focus instruction from the camera CPU 121 .

[0104] As in the first embodiment, the internal memory of the camera CPU 121 stores correction value calculation coefficients required for AF using the output signal from the image sensor 107. A plurality of correction value calculation coefficients are prepared for combinations of the focus state corresponding to the position of the third lens unit 105, the amount of aberration corresponding to the positions of the first and second lens units 101 and 103, the aperture value (i.e., F-number) of the imaging optical system, and the set pupil distance and pixel size of the image sensor 107. When performing AF, the camera CPU 121 calculates a correction value based on the image height on the image sensor 107 and the correction value calculation coefficients corresponding to the combination of the focus state, the amount of aberration, the F-number, the set pupil distance, and the pixel size.

[0105] As described in the first embodiment, when the imaging optical system is set in an interchangeable lens, a memory for storing correction value calculation coefficients is set in the interchangeable lens, and when AF is performed, the correction value can be calculated by using the correction value calculation coefficients obtained from the interchangeable lens by the camera body via communication.

[0106] The operation switch group 132 ′ includes a power switch, a release (imaging trigger) switch, a soft focus operation switch, an imaging mode selection switch, and the like.

[0107] Figure 13 The flowchart in shows the aberration bracketing imaging process executed by the camera CPU 121 according to the computer program in this embodiment.

[0108] Aberration bracketing is imaging that changes the amount of aberration in the imaging optical system by moving the first lens unit 101 and the second lens unit 103 (also referred to as a soft focus lens unit) in the optical axis direction, while acquiring captured images having a corresponding plurality of aberration amounts (i.e., degrees of soft focus). Aberration bracketing can be one of the functions that can be selected by the user via a menu screen of the camera, or can be executed by the user operating an aberration bracketing switch included in the operation switch group 132' or provided on an interchangeable lens. When the user instructs the lens-interchangeable camera to perform aberration bracketing, the camera notifies the interchangeable lens that the instruction for aberration bracketing has been given. When an interchangeable lens including a soft focus lens is attached to the lens-interchangeable camera, the interchangeable lens can notify the camera that aberration bracketing is possible.

[0109] In step S151, the camera CPU 121, which has already started the aberration bracketing imaging process, serves as a setting unit to set the number of imaging times N and the range of change AB of the aberration amount in the aberration bracketing imaging. The number of imaging times N and the range of change AB of the aberration amount may be set by the camera CPU 121 based on the number and range specified in advance by the user, or may be automatically set by the camera CPU 121.

[0110] For example, if the number of images is set to N = 5 and the aberration range is set to AB = ±2, the camera CPU 121 determines to capture five images with five aberration amounts of -2, -1, 0, +1, and +2. When the aberration amount is 0, no aberration occurs. A larger absolute value of the aberration amount indicates a larger aberration amount and a stronger soft focus. As described above, the aberration amount can be represented by a + or - sign and an integer, or by natural numbers, letters, etc., and the representation method is not limited.

[0111] Next, in step S152 , the camera CPU 121 sets the current aberration amount to an initial aberration amount (for example, −2) among the plurality of aberration amounts set in step S151 .

[0112] Next, in step S153, the camera CPU 121 controls the soft focus actuator 111' to move the first lens unit 101 and the second lens unit 103 to positions corresponding to the aberration amount set in step S151. If the imaging optical system is provided on an interchangeable lens, the camera CPU 121 instructs (controls) the interchangeable lens to drive the first lens unit 101 and the second lens unit 103 to positions corresponding to the set aberration amount. This instruction is given each time the aberration amount setting is changed thereafter.

[0113] like Figure 14A and 14B As shown, if the interchangeable lens is provided with an aberration ring that can rotate about the optical axis, a soft focus actuator 111' can rotate the aberration ring to drive the first lens unit 101 and the second lens unit 103 in the direction of the optical axis. The illustrated aberration ring indicates aberration amounts (ABE in the figure) of -2, -1, 0, +1, and +2 in the circumferential direction. Among these aberration amounts, the aberration amount located at the marked position provided on the fixed cylinder of the interchangeable lens is displayed to the user as the current aberration amount. If the soft focus actuator 111' is not provided, the user can manually rotate the aberration ring to move the first lens unit 101 and the second lens unit 103 to change the aberration amount.

[0114] Next, in step S154, the camera CPU 121 executes the Figure 7 The focus detection processing shown in FIG1 is used to calculate the defocus amount in the aberration amount that has been set in step S153 and the previous step, and focus adjustment (AF) is performed by driving the third lens unit 105 based on the defocus amount. In this step, AF is performed to correct the focus shift caused by the change in the aberration amount, and an image focused on the subject is acquired regardless of the aberration amount. At this time, as shown in FIG1 , Figure 11 As described above, the camera CPU 121 selects the defocus amount in the spatial frequency region (level) corresponding to the aberration amount set in step S152.

[0115] Next, in step S155 , the camera CPU 121 starts aberration bracket imaging for the number of times N of imaging set in step S151 , and stores images obtained by the respective imaging times in the flash memory 133 .

[0116] Next, in step S156, the camera CPU 121 determines whether or not aberration bracketing has been completed for the number of times N of imaging has been completed. If aberration bracketing has not yet been completed, the process returns to step S152, the next aberration amount is set, and the next imaging is performed after the first lens unit 101 and the second lens unit 103 are driven (step S153) and focusing is performed (step S154). On the other hand, if aberration bracketing has been completed, the aberration bracketing process is completed, and the acquired N captured images are displayed on the display 131.

[0117] Figures 15A to 15E An example of five captured images acquired by aberration bracket imaging and having different aberration amounts is shown. Figure 15C Compared to the captured image with the aberration amount 0 shown in Figure 15B The captured image with the aberration amount -1 shown in FIG and Figure 15D The captured image with the aberration amount +1 shown in has a slightly higher degree of soft focus. Figure 15A The captured image with the aberration amount -2 shown in FIG and Figure 15E The captured image with an aberration amount of +2 shown in is an image with a higher degree of soft focus. Figure 15B and 15D The captured images and Figure 15A and 15E The captured images have the same aberration amount absolute values of 1 and 2, respectively, but these captured images are acquired by moving the first lens unit 101 and the second lens unit 103 in opposite directions and are therefore different images.

[0118] The degree of soft focus also depends on the arrangement of multiple subjects or imaging conditions such as the F-number and subject distance. Therefore, by displaying multiple captured images obtained through actual imaging with different amounts of aberration, as in this embodiment, the user can easily select a captured image with the desired degree of soft focus.

[0119] In this embodiment, a description has been given of a case where bracketing is performed while the aberration amount is changed. However, parameters other than the aberration amount can also be changed during bracketing. For example, in addition to the aberration amount, the aperture state (i.e., F-number) can also be changed. In this case, aberration bracketing is first performed with the set initial F-number (e.g., F=4), and then with the next set F-number (e.g., F=5.6). This allows multiple captured images with different aberration amounts for different F-numbers to be acquired, and increases the number of soft focus levels that the user can select.

[0120] Fourth embodiment

[0121] Next, a fourth embodiment will be described. In this embodiment, the defocus amount is corrected based on the aberration amount of the imaging optical system.

[0122] Here, a case where a soft focus lens as an interchangeable lens is attached to a lens-interchangeable camera, and the soft focus lens can change or variably set the amount of spherical aberration. The soft focus lens notifies the camera of information about the set aberration amount (also referred to as aberration amount information) via communication.

[0123] Figure 17 The flowchart in FIG. 1 shows the focus detection processing executed by the camera CPU 121 according to the computer program in this embodiment. The processing from step S200 to step S250 is the same as that of FIG. Figure 7 The processing of steps S10 to S60 in is the same.

[0124] When calculating the defocus amount in step S250 , the camera CPU 121 corrects the defocus amount as a result of focus detection using a correction coefficient as correction information described below in step S260 .

[0125] Figure 18 The flowchart in FIG3 shows the process of calculating or acquiring the correction coefficient. In step S310, the camera CPU 121 receives the aberration amount information transmitted from the soft focus lens in step S300. The aberration amount information may be aberration information represented using Zernike coefficients, such as wavefront aberration, or, if the camera CPU 121 recognizes that a soft focus lens is attached based on a lens ID or the like, the aberration amount information may be information regarding the aberration amount value set in the soft focus lens.

[0126] Next, in step S320, the camera CPU 121 determines whether the user has selected to correct or not correct the defocus amount, and, if correction is to be performed, which correction coefficient calculation method the user has selected. In this embodiment, a method for calculating the correction coefficient based on the amount of aberration (also referred to as a correction coefficient that takes aberration into account) and a method for not calculating the correction coefficient based on the amount of aberration (also referred to as a correction coefficient that does not take aberration into account) can be selected as the correction coefficient calculation method.

[0127] In the case where it has been selected not to correct the defocus amount, the process advances to step S330 , the camera CPU 121 sets the correction coefficient to 1, and the process advances to step S360 . In this case, the defocus amount calculated in step S250 is used for AF as it is.

[0128] On the other hand, in the case where the method of calculating the correction coefficient in consideration of aberrations is selected, the process proceeds to step S340 , and in the case where the method of calculating the correction coefficient without consideration of aberrations is selected, the process proceeds to step S350 .

[0129] In step S340, the camera CPU 121 calculates correction coefficients for each defocus amount and each F-number using the aberration amount information received from the soft focus lens. For example, when the fourth-order Zernike coefficient Z representing the spherical aberration amount is obtained from the soft focus lens as the aberration amount information, the correction coefficient Kgain is calculated using the following equation (2).

[0130] Kgain=m1×Z2+m1×Z+m0 (2)

[0131] m2, m1, and m0 in equation (2) are fitting coefficients when the correction coefficient is fitted using the Zernike coefficient Z. The fitting coefficients are stored in the camera CPU 121 as table data for each representative defocus amount and F-number, and fitting coefficients other than the fitting coefficients for the representative defocus amount and F-number are acquired by linear interpolation. Fitting can be first order, third order, or higher order. Fitting can be performed using a plurality of Zernike coefficients.

[0132] The camera CPU 121 may pre-store the defocus amount, F-number, and correction coefficient for each aberration amount, and may select a correction coefficient based on the defocus amount, F-number, and aberration amount when correcting the defocus amount. In addition to varying the correction coefficient depending on the defocus amount, F-number, and aberration amount, the correction coefficient may also vary depending on the spatial frequency band (level).

[0133] The camera CPU 121 uses the correction coefficient acquired in this manner to correct the defocus amount in step S360. Specifically, the defocus amount is corrected using the following equation (3).

[0134] d=p×K×Kgain (3)

[0135] In equation (3), d represents the corrected defocus amount, p represents the image shift amount, and K represents a conversion coefficient for conversion from the image shift amount to the defocus amount.

[0136] Figures 19A to 19C This figure shows examples of correction coefficients based on the amount of spherical aberration. In each graph, the horizontal axis represents the amount of defocus, with the left side of "Focused" indicating the front focal point and the right side indicating the back focal point. "Focused" indicates the position where the defocus amount is almost zero. The vertical axis represents the correction coefficient. Figure 19A The correction coefficients in the case where the amount of aberration is small are shown. The correction coefficients in this case are values that are almost symmetrical with respect to "focus" on the front and back focal sides. On the other hand, Figure 19B and 19C The correction coefficients for cases where the amount of aberration is large are shown. In these cases, the correction coefficients on the front focus side and the back focus side are asymmetric with respect to "focus."

[0137] In step S350, the camera CPU 121 calculates the defocus amount and the correction coefficient for each F number without using the aberration amount information. Thereafter, in step S360, the defocus amount is corrected using the correction coefficient.

[0138] In this embodiment, a description has been given of a case where a soft focus lens with a variable aberration amount is attached to a camera, but even in a case where the aberration amount is not variable, the same processing as in this embodiment can be applied even if a lens with a large aberration amount is attached to the camera.

[0139] Other embodiments

[0140] The embodiments of the present invention can also be implemented by the following method, that is, providing software (program) that performs the functions of the above-mentioned embodiments to a system or device through a network or various storage media, and the computer or central processing unit (CPU) or microprocessing unit (MPU) of the system or device reads and executes the program.

[0141] According to the above embodiments, even when detecting focus via an optical system with large aberrations, a good focus detection result can be obtained. In addition, according to the above embodiments, an image with a degree of soft focus desired by the user can be generated.

[0142] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A camera device comprising: an image sensor including a pair of focus detection pixels configured to receive light beams that have passed through different areas in an exit pupil of an imaging optical system; at least one processor; as well as at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as: a focus detection unit configured to detect a focus of the imaging optical system by using a pair of focus detection signals generated by using output signals from the pair of focus detection pixels, characterised in that the focus detection unit is capable of detecting the focus in a plurality of spatial frequency bands, and Here, the focus detection unit acquires a focus detection result to be used in a spatial frequency band corresponding to an aberration amount of the imaging optical system, the spatial frequency band being included in the plurality of spatial frequency bands.

2. The imaging device according to claim 1, in, The aberration amount is the spherical aberration amount.

3. The imaging device according to claim 1, in, a lens apparatus including the imaging optical system detachably attached to the imaging apparatus, wherein the focus detection unit acquires (a) information related to the aberration amount or (b) information related to a spatial frequency band for detecting the focus from the lens device, the spatial frequency band corresponding to the aberration amount, and Here, the focus detection unit acquires a focus detection result to be used in a spatial frequency band selected from the plurality of spatial frequency bands based on the information.

4. The imaging device according to claim 1, in, a lens apparatus including the imaging optical system detachably attached to the imaging apparatus, wherein the focus detection unit acquires (a) information related to the aberration amount or (b) information related to a spatial frequency band for detecting the focus from the lens device, the spatial frequency band corresponding to the aberration amount, and Here, the focus detection unit selects a focus detection result to be used from the focus detection results in the plurality of spatial frequency bands based on the information.

5. The imaging device according to claim 1, in, The focus detection unit acquires a focus detection result to be used in a spatial frequency band that decreases as the amount of aberration increases.

6. The imaging device according to claim 1, in, The focus detection unit acquires a focus detection result to be used in a spatial frequency band that differs according to an F-number of the imaging optical system.

7. The imaging apparatus according to any one of claims 1 to 6, in, The image pickup apparatus provides control of focusing of the imaging optical system based on a focus detection result to be used.

8. A lens apparatus that is detachably attached to the image pickup apparatus according to any one of claims 1 to 7 and has an imaging optical system, the lens apparatus comprising: at least one processor; as well as at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as: a storage unit configured to store (a) information related to an aberration amount of the imaging optical system or (b) information related to a spatial frequency band for detecting a focus, the spatial frequency band corresponding to the aberration amount; as well as A notification unit is configured to notify the imaging device of the information.

9. The lens device according to claim 8, in, The aberration amount of the imaging optical system can be changed.

10. A method for controlling an imaging device, the imaging device including an image sensor, the image sensor including a pair of focus detection pixels, the pair of focus detection pixels being configured to receive light beams that have passed through different areas in an exit pupil of an imaging optical system, the method comprising: generating a pair of focus detection signals by using output signals from the pair of focus detection pixels; as well as A focus detection result to be used is acquired in a spatial frequency band corresponding to an aberration amount of the imaging optical system, the spatial frequency band being included in a plurality of spatial frequency bands capable of detecting a focus of the imaging optical system by using the pair of focus detection signals.

11. A method for controlling a lens device that is detachably attached to an image pickup device and includes an imaging optical system, the method according to claim 10 being used for the image pickup device, the method comprising: storing (a) information related to an amount of aberration of the imaging optical system or (b) information related to a spatial frequency band for detecting a focus, the spatial frequency band corresponding to the amount of aberration; as well as The imaging device is notified of the information. 12 . A non-transitory computer-readable storage medium storing a computer program for causing a computer of an imaging apparatus to execute the control method according to claim 10 . 13 . A non-transitory computer-readable storage medium storing a computer program for causing a computer of a lens device to execute the control method according to claim 11 .

14. A camera device comprising: an image sensor configured to capture an image by receiving a light beam from an imaging optical system and including a pair of focus detection pixels configured to receive light beams that have passed through different areas in an exit pupil of the imaging optical system; at least one processor; as well as at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as: a focus detection unit configured to detect a focus of the imaging optical system by using a pair of focus detection signals generated by using output signals from the pair of focus detection pixels, It is characterized in that the imaging optical system can change the amount of aberration, wherein the at least one processor is caused to also function as a control unit configured to provide control of focusing of the imaging optical system based on a focus detection result and capture an image each time the aberration amount is changed, wherein the focus detection unit is capable of detecting the focus in a plurality of spatial frequency bands, and Here, the focus detection unit acquires a focus detection result to be used in a spatial frequency band corresponding to the aberration amount, the spatial frequency band being included in the plurality of spatial frequency bands.

15. The imaging device according to claim 14, in, The aberration amount is the spherical aberration amount.

16. The imaging device according to claim 14, in, The at least one processor is caused to further function as a setting unit configured to set the number of times images are captured with respective aberration amounts set differently from each other.

17. The imaging device according to claim 14, in, A lens apparatus including the imaging optical system is detachably attached to the imaging apparatus, and The control unit obtains information related to the aberration amount from the lens device.

18. The imaging device according to claim 14, in, A lens apparatus including the imaging optical system is detachably attached to the imaging apparatus, and The control unit controls the change of the aberration amount in the lens device.

19. A camera device comprising: an image sensor including a pair of focus detection pixels configured to receive light beams that have passed through different areas in an exit pupil of an imaging optical system; at least one processor; as well as at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, cause the at least one processor to function as: a focus detection unit configured to detect a focus of the imaging optical system by using a pair of focus detection signals generated by using output signals from the pair of focus detection pixels; as well as a control unit configured to acquire correction information corresponding to an amount of aberration of the imaging optical system and correct a focus detection result using the correction information, wherein the focus detection unit is capable of detecting the focus in a plurality of spatial frequency bands, and Here, the focus detection unit acquires a focus detection result to be used in a spatial frequency band corresponding to an aberration amount of the imaging optical system, the spatial frequency band being included in the plurality of spatial frequency bands.

20. The imaging device according to claim 19, in, The aberration amount is the spherical aberration amount.

21. The imaging device according to claim 19, in, A lens apparatus including the imaging optical system is detachably attached to the imaging apparatus, and The control unit obtains information related to the aberration amount from the lens device.

22. The imaging device according to claim 19, in, The correction information differs depending on the focus detection result.

23. The imaging device according to any one of claims 19 to 22, in, The imaging optical system is capable of changing the aberration amount.

24. A method for controlling an imaging apparatus, the imaging apparatus comprising an image sensor configured to capture an image by receiving a light beam from an imaging optical system, the image sensor comprising a pair of focus detection pixels configured to receive light beams having passed through different areas in an exit pupil of the imaging optical system, It is characterized in that The imaging optical system is capable of changing the amount of aberration, Wherein, the control method includes: detecting a focus of the imaging optical system by using a pair of focus detection signals generated by using output signals from the pair of focus detection pixels; and providing control of focusing of the imaging optical system based on a focus detection result and capturing an image each time the aberration amount is changed, wherein the control method is capable of detecting the focus in a plurality of spatial frequency bands, and Here, the control method acquires a focus detection result to be used in a spatial frequency band corresponding to the aberration amount, the spatial frequency band being included in the plurality of spatial frequency bands.

25. A method for controlling an imaging device, the imaging device comprising an image sensor, the image sensor comprising a pair of focus detection pixels, the pair of focus detection pixels being configured to receive light beams that have passed through different areas in an exit pupil of an imaging optical system, the method comprising: detecting a focus of the imaging optical system by using a pair of focus detection signals generated by using output signals from the pair of focus detection pixels; as well as acquiring correction information corresponding to the aberration amount of the imaging optical system, and correcting a focus detection result using the correction information, wherein the control method is capable of detecting the focus in a plurality of spatial frequency bands, and Here, the control method acquires a focus detection result to be used in a spatial frequency band corresponding to an aberration amount of the imaging optical system, the spatial frequency band being included in the plurality of spatial frequency bands. 26 . A non-transitory computer-readable storage medium storing a computer program for causing a computer of an imaging apparatus to execute the control method according to claim 24 . 27 . A non-transitory computer-readable storage medium storing a computer program for causing a computer of an imaging apparatus to execute the control method according to claim 25 .

28. A computer program product comprising a program, wherein when the program is executed by a processor, the program causes a computer of an imaging device to execute the control method according to any one of claims 10, 24, and 25.

29. A computer program product comprising a program, which, when executed by a processor, causes a computer of a lens device to execute the control method according to claim 11.

Images