Imaging element, focus detection device, and imaging device

Abstract

An imaging element comprises: a first pixel and a second pixel that respectively have a pair of photoelectric conversion units for receiving light fluxes passing through different pupil regions of an exit pupil in an optical system, and output a signal used for focus detection in the optical system; and a control unit that performs a first control for outputting both the signal of one pixel selected from the first pixel and the second pixel and the signal of the other pixel out of the first pixel and the second pixel, and a second control for outputting the signal of the one pixel out of the first pixel and the second pixel.

Description

Image sensor, focus detection device, and image pickup device

[0001] The present invention relates to an image sensor, a focus detection device, and an image pickup device.

[0002] An imaging device is known that performs focus detection by selecting an AF pixel pair from a plurality of types of AF pixel pairs according to the position of the exit pupil of a lens (see Japanese Patent Laid-Open No. 2007-122294). Improved focus detection accuracy has been desired for some time.

[0003] Japanese Patent Application Laid-Open No. 2009-204987

[0004] According to one aspect of the disclosure, the image sensor includes a first pixel and a second pixel, each having a pair of photoelectric conversion units that receive light beams that pass through different pupil regions of an exit pupil of an optical system, and that output a signal used for focus detection of the optical system; and a control unit that performs first control to output both a signal from a selected one of the first pixel and the second pixel and a signal from the other of the first pixel and the second pixel, and second control to output the signal from the one of the first pixel and the second pixel.

[0005] According to another disclosed aspect, an imaging device includes the imaging element and a generating unit that generates image data based on a signal output from the imaging element.

[0006] According to another disclosed aspect, a focus detection device includes an imaging unit having a first pixel and a second pixel, each pixel having a pair of photoelectric conversion units that receive light beams that pass through different pupil regions of an exit pupil of an optical system; a detection unit that performs focus detection of the optical system based on each of the signals of the first pixel and the second pixel; a selection unit that selects one of the first pixel and the second pixel; and a control unit that controls a position of the optical system. If the detection unit is unable to perform focus detection of the optical system based on the signal of one of the first pixel and the second pixel but is able to perform focus detection of the optical system based on the signal of the other of the first pixel and the second pixel, the control unit controls the position of the optical system after a first period has elapsed since receiving an instruction to perform focus detection of the optical system; and if the detection unit is unable to perform focus detection of the optical system based on either the signal of the first pixel or the signal of the second pixel, the control unit controls the position of the optical system after a second period, which is shorter than the first period, has elapsed since receiving an instruction to perform focus detection of the optical system.

[0007] According to another disclosed aspect, an imaging device includes the focus detection device described above and an attachment / detachment unit to which an interchangeable lens having the optical system can be attached / detached.

[0008] The configurations of the embodiments described below may be modified as appropriate, and at least a portion of the configuration may be replaced with other components. Furthermore, components that are not particularly limited in terms of their placement may be placed in any position that can achieve their function, not limited to the placement disclosed in the embodiments.

[0009] FIG. 1 is a diagram illustrating an example of the configuration of an imaging device according to an embodiment. FIG. 2A is a diagram illustrating a focus detection area on an imaging surface of an image sensor, and FIG. 2B is a diagram illustrating a small area within the focus detection area. FIG. 3 is a diagram illustrating an example of the arrangement of pixels within the focus detection area. FIG. 4 is a diagram illustrating the relationship between a first pixel group, a second pixel group, a third pixel group, and the focus detection area. FIGS. 5A to 5C are diagrams illustrating an example of the configuration of focus detection pixels and imaging pixels provided in a pixel unit. FIGS. 6A and 6B are diagrams illustrating focus detection based on first and second signals output from an AF pixel pair selected by a selection unit. FIG. 7 is a flowchart (part 1) illustrating an example of processing performed by a body control unit according to an embodiment. FIG. 8 is a flowchart (part 2) illustrating an example of processing performed by a body control unit according to an embodiment. FIG. 9 is a flowchart (part 3) illustrating an example of processing performed by a body control unit according to an embodiment. FIG. 10 is a diagram schematically illustrating processing performed by a body control unit according to an embodiment. Fig. 11 is a graph showing an example of the relationship between the position of the focus lens and the reliability calculated by the subject detection unit. Fig. 12 is a flowchart (part 1) showing an example of processing executed by the body control unit according to a modified example. Fig. 13 is a flowchart (part 2) showing an example of processing executed by the body control unit according to a modified example. Fig. 14 is a flowchart (part 3) showing an example of processing executed by the body control unit according to a modified example. Fig. 15 is a flowchart (part 4) showing an example of processing executed by the body control unit according to a modified example. Fig. 16 is a flowchart (part 5) showing an example of processing executed by the body control unit according to a modified example. Fig. 17 is a diagram schematically showing the processing of steps S101 to S135.

[0010] An electronic camera 1 (hereinafter referred to as camera 1) as an example of an imaging apparatus according to an embodiment will be described below with reference to FIGS.

[0011] 1 is a diagram showing an example of the configuration of an electronic camera 1 (hereinafter referred to as camera 1) according to one embodiment. The camera 1 comprises a camera body 2 and an interchangeable lens 3. Because the camera 1 comprises the camera body 2 and the interchangeable lens 3, it is sometimes referred to as a camera system.

[0012] (Interchangeable Lens 3) The interchangeable lens 3 includes a lens-side mount unit 301, a photographing optical system (imaging optical system) 31, a lens control unit 32, and a lens memory 33. The lens-side mount unit 301 includes a lens-side connection unit 302. The lens-side connection unit 302 has multiple terminals, such as a terminal for a clock signal, a terminal for a data signal, and a terminal for power supply. The interchangeable lens 3 is detachably attached to the camera body 2 by the lens-side mount unit 301 and a body-side mount unit 201, which will be described later.

[0013] The photographic optical system 31 includes a plurality of lenses, including a zoom lens (variable magnification lens) 31a that changes the focal length and a focus lens (focus adjustment lens) 31b, and an aperture 31c, and forms a subject image on the imaging surface 22a of the image sensor 22. Note that although the zoom lens 31a and the focus lens 31b are shown in Fig. 1 as a schematic illustration, a typical photographic optical system is generally made up of a large number of optical elements.

[0014] As will be described later, the photographing optical system 31 of the interchangeable lens 3 has an optical characteristic in which the position of its exit pupil, i.e., the exit pupil distance, changes depending on the image height. In other words, the exit pupil distance of the photographing optical system 31 changes depending on the position on the imaging plane 22a, i.e., the distance from the optical axis OA1 of the photographing optical system 31 to the imaging plane 22a. The optical axis OA1 of the photographing optical system 31 intersects with the imaging plane 22a at the center of the imaging plane 22a. It can also be said that the exit pupil distance of the photographing optical system 31 changes depending on the distance from the center of the imaging plane 22a. Here, the exit pupil distance is the distance between the exit pupil of the photographing optical system 31 and the image plane of the image formed by the photographing optical system 31. The imaging plane 22a of the image sensor 22 is, for example, a surface on which a photoelectric conversion unit (described later) or a surface on which microlenses are arranged.

[0015] The photographic optical system 31 differs depending on the type of interchangeable lens 3 attached to the body side mount unit 201. Therefore, the exit pupil distance of the photographic optical system 31 differs depending on the type of interchangeable lens 3. Furthermore, the optical characteristics of the exit pupil distance, which changes depending on the image height, also differ depending on the type of interchangeable lens 3.

[0016] The lens control unit 32 is composed of a processor such as a CPU, FPGA, or ASIC, and memories such as ROM and RAM, and controls each unit of the interchangeable lens 3 based on a control program. The lens control unit 32 controls the position of the zoom lens 31a, the position of the focus lens 31b, and the drive of the diaphragm 31c based on signals output from the body control unit 21 of the camera body 2. When a signal indicating the movement direction and amount of the focus lens 31b is input from the body control unit 21, the lens control unit 32 moves the focus lens 31b back and forth along the optical axis OA1 based on the signal to adjust the focal position of the photographing optical system 31. The lens control unit 32 also controls the position of the zoom lens 31a and the opening diameter of the diaphragm 31c based on signals output from the body control unit 21 of the camera body 2.

[0017] The lens memory 33 is composed of, for example, a non-volatile storage medium. Information related to the interchangeable lens 3 is stored (recorded) in the lens memory 33 as lens information. The lens information includes data on the optical characteristics (exit pupil distance and F-number) of the photographic optical system 31, data on the infinity position and close position of the focus lens 31b, and data on the shortest focal length and longest focal length of the interchangeable lens 3. The optical characteristics of the photographic optical system 31 include the exit pupil distance and F-number (aperture value of the diaphragm 31c). The lens information differs depending on the type of interchangeable lens 3. The lens information may also be stored in an internal memory of the lens control unit 32. The lens information may also be stored in a body memory 23 included in the camera body 2, which will be described later. In this case, the body memory 23 stores lens information for multiple interchangeable lenses 3.

[0018] In this embodiment, the lens information includes information regarding the exit pupil distance of the photographing optical system 31. The information regarding the exit pupil distance includes information indicating the exit pupil distance (Co) at the position where the imaging plane 22a and the optical axis OA1 intersect (the position where the image height is zero) and information regarding a coefficient included in an arithmetic expression expressing the relationship between the exit pupil distance and the image height. The writing of data to the lens memory 33 and the reading of data from the lens memory 33 are controlled by the lens control unit 32. When the interchangeable lens 3 is attached to the camera body 2, the lens control unit 32 transmits the lens information to the body control unit 21 via the terminals of the lens side connection unit 302 and the body side connection unit 202. The lens control unit 32 also transmits to the body control unit 21 position information (focal length information) of the controlled zoom lens 31a, position information of the controlled focus lens 31b, information regarding the F-number of the controlled aperture 31c, and the like.

[0019] The lens control unit 32 communicates by sending and receiving information bidirectionally between the camera body 2 and the interchangeable lens 3 via the terminals of the lens-side connection unit 302 and the body-side connection unit 202. When a signal requesting the transmission of information regarding the exit pupil distance is input from the camera body 2, the lens control unit 32 transmits information regarding the exit pupil distance to the camera body 2. Note that the information regarding the exit pupil distance differs depending on the type of interchangeable lens 3. The lens control unit 32 may also transmit information regarding the exit pupil distance to the camera body 2 each time the image sensor 22 captures an image. The lens control unit 32 may also transmit information regarding the exit pupil distance to the camera body 2 when the zoom lens 31a moves and the focal length of the photographic optical system 31 changes. The lens control unit 32 may transmit information regarding the focal length of the photographic optical system 31 and information regarding the exit pupil distance to the camera body 2 in a single bidirectional communication.

[0020] (Camera Body 2) The camera body 2 includes a body-side mount unit 201, an image sensor 22, a body memory 23, a display unit 24, an operation unit 25, and a body control unit 21. In this embodiment, the image sensor 22 and the body control unit 21 constitute the focus detection device 4.

[0021] The body side mount section 201 includes a body side connection section 202. The body side connection section 202 has a plurality of terminals, such as a terminal for a clock signal, a terminal for a data signal, and a terminal for power supply.

[0022] When the interchangeable lens 3 is attached to the camera body 2, a terminal provided on the body-side connector 202 is electrically connected to a terminal provided on the lens-side connector 302. This enables power to be supplied from the camera body 2 to the interchangeable lens 3 and communication between the camera body 2 and the interchangeable lens 3.

[0023] The imaging element 22 is a CMOS image sensor or a CCD image sensor. The imaging element 22 captures an image of a subject formed by the photographing optical system 31. The imaging element 22 includes a pixel unit 221 in which a plurality of pixels each having a photoelectric conversion unit are arranged two-dimensionally (in the row and column directions), and a control unit 222 that controls the pixel unit 221. The photoelectric conversion unit is composed of a photodiode (PD).

[0024] As will be described later, the pixel unit 221 includes imaging pixels that photoelectrically convert received light using a photoelectric conversion unit to output signals used for image generation, and focus detection pixels that photoelectrically convert received light using a photoelectric conversion unit to output signals used for focus detection. The imaging pixels include pixels (hereinafter referred to as R pixels) that have filters with spectral characteristics that separate incident light in a first wavelength range (red (R) light), pixels (hereinafter referred to as G pixels) that have filters with spectral characteristics that separate incident light in a second wavelength range (green (G) light), and pixels (hereinafter referred to as B pixels) that have filters with spectral characteristics that separate incident light in a third wavelength range (blue (B) light). The R, G, and B pixels are arranged in a Bayer array. The focus detection pixels are arranged to replace some of the imaging pixels and are distributed across substantially the entire imaging surface 22a of the image sensor 22.

[0025] The control unit 222 causes the focus detection pixel signals to be output based on an instruction signal from the body control unit 21. The control unit 222 also causes the imaging pixel signals to be output based on an instruction signal from the body control unit 21.

[0026] The body memory 23 is composed of, for example, a non-volatile storage medium, etc. Image data, control programs, etc. are recorded in the body memory 23. Writing data to the body memory 23 and reading data from the body memory 23 are controlled by the body control unit 21. The display unit 24 displays an image based on the image data, an image showing a focus detection area (AF area) such as an AF frame, information related to shooting such as the shutter speed and F-number, a menu screen, etc.

[0027] The operation unit 25 includes various setting switches such as a release button, a power switch, and switches for switching between various modes, and outputs operation signals corresponding to the respective operations to the body control unit 21. The operation unit 25 is also a setting unit that can set an arbitrary focus detection area from a plurality of focus detection areas, and the user can select an arbitrary focus detection area by operating the operation unit 25.

[0028] The body control unit 21 is configured with a processor such as a CPU, FPGA, or ASIC, and memories such as ROM and RAM, and controls each unit of the camera 1 based on a control program. The body control unit 21 has an image data generation unit 211, a subject detection unit 212, an area setting unit 213, a distance calculation unit 214, a selection unit 215, a focus detection unit 216, and a position control unit 217. The image data generation unit 211, the subject detection unit 212, the area setting unit 213, the distance calculation unit 214, the selection unit 215, the focus detection unit 216, and the position control unit 217 are realized, for example, by the processor executing a program.

[0029] The image data generation unit 211 generates image data by performing various image processing on signals output from the imaging pixels of the image sensor 22. Note that the image data generation unit 211 may also generate image data using signals output from the focus detection pixels.

[0030] The subject detection unit 212 detects a predetermined subject from an image based on the image data generated by the image data generation unit 211. For example, when a "bird mode" suitable for photographing wild birds or the like is set as the shooting mode, the subject detection unit 212 detects a bird as the subject. When an "airplane mode" suitable for photographing airplanes is set as the shooting mode, the subject detection unit 212 detects an airplane as the subject. When a "portrait mode" suitable for photographing people is set as the shooting mode, the subject detection unit 212 detects a person as the subject.

[0031] The area setting unit 213 sets (selects) at least one focus detection area 100 from among the multiple focus detection areas 100 provided on the imaging surface 22a of the image sensor 22 shown in Fig. 2A. The multiple AF frames displayed on the display unit 24 correspond to the multiple focus detection areas 100 provided on the image sensor 22. For example, the area setting unit 213 sets, as an area for focus detection, the focus detection area 100 corresponding to the AF frame selected by the user by operating the operation unit 25 from among the multiple AF frames displayed on the display unit 24, or the focus detection area 100 corresponding to the AF frame including the subject detected by the subject detection unit 212.

[0032] In each focus detection area 100, in addition to imaging pixels, a plurality of types of pairs of focus detection pixels (AF pixel pairs) are arranged.

[0033] 3 is a diagram showing an example of pixel arrangement within the focus detection area 100. In Fig. 3, a first pixel group 401 in which R pixels 13 and G pixels 13 are arranged alternately in the ±X directions, i.e., in the row direction, and a second pixel group 402 in which G pixels 13 and B pixels 13 are arranged alternately in the ±Y directions, i.e., in the column direction, are arranged alternately. The imaging pixels 13 are arranged according to a Bayer array.

[0034] Some of the multiple second pixel groups 402 include the first or second focus detection pixel 11, 12. The first and second focus detection pixels 11, 12 each have a light-shielding portion 43. In FIG. 3 , the second pixel groups 402 including the first focus detection pixel 11 are indicated as second pixel groups 402a, 402c, and 402e, and the second pixel groups 402 including the second focus detection pixel 12 are indicated as second pixel groups 402b, 402d, and 402f. The second pixel groups 402a, 402c, and 402e including the first focus detection pixel 11 and the second pixel groups 402b, 402d, and 402f including the second focus detection pixel 12 will be described below.

[0035] In the second pixel group 402a, the B pixels 13 are replaced with the first focus detection pixels 11a. In the second pixel group 402a, the first focus detection pixels 11a and the G pixels 13 are arranged alternately. The photoelectric conversion units of the first focus detection pixels 11a receive light beams that have passed through one of the first and second pupil regions of the exit pupil of the photographing optical system 31. The light-shielding units 43 of the first focus detection pixels 11a block light beams that have passed through the other of the first and second pupil regions of the exit pupil of the photographing optical system 31. In the following description, it is assumed that the photoelectric conversion units of the first focus detection pixels 11a receive light beams that have passed through the first pupil region of the exit pupil of the photographing optical system 31. It is assumed that the light-shielding units 43 of the first focus detection pixels 11a block light beams that have passed through the second pupil region of the exit pupil of the photographing optical system 31.

[0036] In the second pixel group 402b, which is a predetermined number of rows away from the second pixel group 402a, the B pixels 13 are replaced with second focus detection pixels 12a. In the second pixel group 402b, the second focus detection pixels 12a and G pixels 13 are arranged alternately. The photoelectric conversion units of the second focus detection pixels 12a receive light beams that have passed through a pupil region of an exit pupil different from that of the first focus detection pixel 11a. The light-shielding units 43 of the second focus detection pixels 12a block light beams that have passed through a pupil region of an exit pupil different from that of the first focus detection pixel 11a. In the following description, the photoelectric conversion units of the second focus detection pixels 12a receive light beams that have passed through a second pupil region of the exit pupil of the photographing optical system 31. The light-shielding units 43 of the second focus detection pixels 12a block light beams that have passed through a first pupil region of the exit pupil of the photographing optical system 31.

[0037] The arrangement position of the first focus detection pixel 11a in the second pixel group 402a and the arrangement position of the second focus detection pixel 12a in the second pixel group 402b are the same, i.e., the first focus detection pixel 11a and the second focus detection pixel 12a are arranged in the same column.

[0038] The first focus detection pixel 11a of the second pixel group 402a and the second focus detection pixel 12a of the second pixel group 402b constitute a first AF pixel pair PR1. Note that the second pixel groups 402a and 402b may be arranged in multiple rows, resulting in multiple first AF pixel pairs PR1. A pixel set including the first AF pixel pair PR1 and the imaging pixel 13 is referred to as a first pixel set 400-1.

[0039] In the second pixel group 402c, which is a predetermined number of rows away from the second pixel group 402b, the B pixels 13 are replaced with the first focus detection pixels 11b. In the second pixel group 402c, the first focus detection pixels 11b and G pixels 13 are arranged alternately. Like the first focus detection pixel 11a, the photoelectric conversion unit of the first focus detection pixel 11b receives the light beam that has passed through a first pupil region of the exit pupil of the photographing optical system 31. Like the light-shielding unit 43 of the first focus detection pixel 11a, the light-shielding unit 43 of the first focus detection pixel 11b blocks the light beam that has passed through a second pupil region of the exit pupil of the photographing optical system 31.

[0040] In a second pixel group 402d, which is a predetermined number of rows away from the second pixel group 402c, the B pixels 13 are replaced with second focus detection pixels 12b. In the second pixel group 402d, the second focus detection pixels 12b and G pixels 13 are arranged alternately. Like the second focus detection pixel 12a, the photoelectric conversion units of the second focus detection pixels 12b receive light beams that have passed through a second pupil region of the exit pupil of the photographing optical system 31. Like the light-shielding unit 43 of the second focus detection pixel 12a, the light-shielding unit 43 of the second focus detection pixel 12b blocks light beams that have passed through a first pupil region of the exit pupil of the photographing optical system 31.

[0041] The arrangement position of the first focus detection pixel 11b in the second pixel group 402c and the arrangement position of the second focus detection pixel 12b in the second pixel group 402d are the same, i.e., the first focus detection pixel 11b and the second focus detection pixel 12b are arranged in the same column.

[0042] The first focus detection pixel 11b of the second pixel group 402c and the second focus detection pixel 12b of the second pixel group 402d constitute a second AF pixel pair PR2. Note that the second pixel groups 402c and 402d may be arranged in multiple rows, resulting in multiple second AF pixel pairs PR2. A pixel set including the second AF pixel pair PR2 and the imaging pixel 13 is referred to as a second pixel set 400-2.

[0043] In a second pixel group 402e, which is a predetermined number of rows away from the second pixel group 402d, the B pixels 13 are replaced with first focus detection pixels 11c. In the second pixel group 402e, the first focus detection pixels 11c and G pixels 13 are arranged alternately. The photoelectric conversion unit of the first focus detection pixel 11c, like the first focus detection pixels 11a and 11b, receives light beams that have passed through a first pupil region of the exit pupil of the photographing optical system 31. The light-shielding unit 43 of the first focus detection pixel 11c, like the light-shielding units 43 of the first focus detection pixels 11a and 11b, blocks light beams that have passed through a second pupil region of the exit pupil of the photographing optical system 31.

[0044] In a second pixel group 402f, which is a predetermined number of rows away from the second pixel group 402e, the B pixels 13 are replaced with second focus detection pixels 12c. In the second pixel group 402f, the second focus detection pixels 12c and the G pixels 13 are arranged alternately. The photoelectric conversion units of the second focus detection pixels 12c receive light beams that have passed through a second pupil region of the exit pupil of the photographing optical system 31. The light-shielding units 43 of the second focus detection pixels 12c, like the light-shielding units 43 of the second focus detection pixels 12a and 12b, block light beams that have passed through a first pupil region of the exit pupil of the photographing optical system 31.

[0045] The position of the first focus detection pixel 11c in the second pixel group 402e and the position of the second focus detection pixel 12c in the second pixel group 402f are the same, i.e., the first focus detection pixel 11c and the second focus detection pixel 12c are arranged in the same column.

[0046] The first focus detection pixel 11c of the second pixel group 402e and the second focus detection pixel 12c of the second pixel group 402f constitute a third AF pixel pair PR3. Note that the second pixel groups 402e and 402f may be arranged in multiple rows, resulting in multiple third AF pixel pairs PR3. A pixel set including the third AF pixel pair PR3 and the imaging pixel 13 is referred to as a third pixel set 400-3.

[0047] 4 is a diagram showing the relationship between a first pixel set 400-1, a second pixel set 400-2, a third pixel set 400-3, and a focus detection area 100. As shown in FIG. 4, each focus detection area 100 includes a first pixel set 400-1, a second pixel set 400-2, and a third pixel set 400-3. The first pixel sets 400-1 of the focus detection areas 100 that are adjacent in the X direction (row direction) are adjacent to each other in the X direction. The second pixel sets 400-2 of the focus detection areas 100 that are adjacent to each other in the X direction are adjacent to each other in the X direction. The third pixel sets 400-3 of the focus detection areas 100 that are adjacent to each other in the X direction are adjacent to each other in the X direction. 4, the first pixel set 400-1, the second pixel set 400-2, and the third pixel set 400-3 are arranged consecutively in the X direction (row direction), while the first pixel set 400-1, the second pixel set 400-2, and the third pixel set 400-3 are arranged repeatedly in this order in the Y direction (column direction).

[0048] The areas of the light-shielding portions 43 of the first AF pixel pair PR1, the second AF pixel pair PR2, and the third AF pixel pair PR3 are different, except for pixel pairs located around the optical axis OA1 of the photographing optical system 31 (the center of the image pickup surface 22a). When the exit pupil distance is different, the angle of incidence of light incident on the focus detection pixels is different, except for focus detection pixels located around the optical axis OA1 of the photographing optical system 31. The shorter the exit pupil distance, the larger the angle of incidence, and the longer the exit pupil distance, the smaller the angle of incidence. The areas of the light-shielding portions 43 differ for each AF pixel pair in order to block a portion of the light incident at different angles depending on the exit pupil distance. This allows the focus detection unit 216 to accurately detect the defocus amount even at different exit pupil distances. However, the angle of incidence of pixel pairs located around the optical axis OA1 of the photographing optical system 31 (the center of the image pickup surface 22a) is 0° regardless of the exit pupil distance. Therefore, the areas of the light-shielding portions 43 of the first AF pixel pair PR1, the second AF pixel pair PR2, and the third AF pixel pair PR3 located around the optical axis OA1 (center of the imaging surface 22a) of the photographing optical system 31 are the same. The areas of the light-shielding portions 43 also differ depending on the position (image height) of the focus detection pixel.

[0049] In this embodiment, the first focus detection pixels 11a to 11c and the second focus detection pixels 12a to 12c each have a filter with spectral characteristics that separates light in a second wavelength range (green (G) light) from the incident light. Note that the filters of the first focus detection pixels 11a to 11c and the second focus detection pixels 12a to 12c may also be filters with spectral characteristics that separate light in a first wavelength range (red (R) light) or light in a third wavelength range (blue (B) light). Furthermore, the first focus detection pixels 11a to 11c and the second focus detection pixels 12a to 12c may also have filters with spectral characteristics that separate light in the first, second, and third wavelength ranges from the incident light.

[0050] 5A to 5C are diagrams illustrating exemplary configurations of focus detection pixels and imaging pixels provided in the pixel section 221. Fig. 5A shows an exemplary cross section of the first focus detection pixel 11 of the first and second focus detection pixels 11, 12 that make up an AF pixel pair, and Fig. 5B shows an exemplary cross section of the second focus detection pixel 12 of the first and second focus detection pixels 11, 12. Fig. 5C shows an exemplary cross section of an imaging pixel 13 (R pixel, G pixel, B pixel).

[0051] 5A to 5C, the first and second focus detection pixels 11, 12 and the imaging pixel 13 each have a microlens 44, a color filter 51, and a photoelectric conversion unit 42 (PD 42). The photoelectric conversion unit 42 photoelectrically converts light that has transmitted (passed) through the microlens 44 and the color filter 51. A first light beam 61 is a light beam that has passed through a first pupil region that divides the exit pupil of the photographing optical system 31 into approximately two equal parts. A second light beam 62 is a light beam that has passed through a second pupil region that divides the exit pupil of the photographing optical system 31 into approximately two equal parts.

[0052] In FIG. 5A , the first focus detection pixel 11 is provided with a light-shielding portion 43 that blocks the second light beam 62 of the first and second light beams 61, 62. The light-shielding portion 43 is located between the color filter 51 and the photoelectric conversion portion 42 and is provided on the photoelectric conversion portion 42. In the example shown in FIG. 5A , the light-shielding portion 43 is disposed so as to block the left half (the −X direction side) of the photoelectric conversion portion 42. The right end (the end in the +X direction) of the light-shielding portion 43 approximately coincides with the center line that divides the photoelectric conversion portion 42 into left and right halves. The photoelectric conversion portion 42 of the first focus detection pixel 11 receives the first light beam 61. The photoelectric conversion portion 42 of the first focus detection pixel 11 photoelectrically converts the first light beam 61 to generate an electric charge, and the first focus detection pixel 11 outputs a first signal Sig1 based on the electric charge generated by the photoelectric conversion portion 42.

[0053] The area of ​​the light-shielding portion 43 varies depending on the position (image height) of the first focus detection pixel 11, except for the first focus detection pixels 11 located around the optical axis OA1 (center of the image pickup surface 22a) of the photographing optical system 31. When the position of the first focus detection pixel 11 varies, i.e., when the image height varies, the angle of incidence of light incident on the first focus detection pixel 11 varies. The angle of incidence increases as the image height increases, and decreases as the image height decreases, and when the image height is zero, the angle of incidence is 0°. The area of ​​the light-shielding portion 43 varies depending on the image height in order to block the second light beam 62, which is part of the light incident at angles of incidence that vary depending on the image height.

[0054] In FIG. 5B , the second focus detection pixel 12 is provided with a light-shielding portion 43 that blocks the first light beam 61 of the first and second light beams 61, 62. The light-shielding portion 43 is located between the color filter 51 and the photoelectric conversion portion 42 and is provided on the photoelectric conversion portion 42. In the example shown in FIG. 5B , the light-shielding portion 43 is disposed so as to block the right half (the +X direction side) of the photoelectric conversion portion 42. The left end (the end in the −X direction) of the light-shielding portion 43 approximately coincides with the center line that divides the photoelectric conversion portion 42 into left and right halves. The photoelectric conversion portion 42 of the second focus detection pixel 12 receives the second light beam 62. The photoelectric conversion portion 42 of the second focus detection pixel 12 photoelectrically converts the second light beam 62 to generate an electric charge, and the second focus detection pixel 12 outputs a second signal Sig2 based on the electric charge generated by the photoelectric conversion portion 42.

[0055] As with the first focus detection pixels 11, the area of ​​the light-shielding portion 43 varies depending on the position (image height) of the second focus detection pixels 12, except for the second focus detection pixels 12 located around the optical axis OA1 (center of the imaging surface 22a) of the imaging optical system 31. The area of ​​the light-shielding portion 43 varies depending on the image height in order to block the first light beam 61 of light incident at different angles of incidence depending on the image height. The area of ​​the light-shielding portion 43 can be set according to the position (image height) of the focus detection pixel, for example, as disclosed in WO2020 / 017640.

[0056] 5C , the photoelectric conversion unit 42 of the imaging pixel 13 receives first and second light beams 61 and 62 that have passed through first and second pupil regions, respectively, of the exit pupil of the imaging optical system 31. The photoelectric conversion unit 42 of the imaging pixel 13 photoelectrically converts the first and second light beams 61 and 62 to generate electric charges, and the imaging pixel 13 outputs a signal (image signal) based on the electric charges generated by the photoelectric conversion unit 42.

[0057] As shown in FIG. 2A, the multiple focus detection areas 100 are arranged in two dimensions (row and column directions) and are provided at different image heights. A small area 110a (see FIG. 2B) within the focus detection area 100a at the center of the imaging surface 22a is located on the optical axis OA1 of the photographing optical system 31, and its image height H is approximately zero. The image height H of the focus detection area 100 increases as it moves away from the center of the imaging surface 22a (the optical axis OA1 of the photographing optical system 31). In other words, the image height H of the focus detection area 100 increases as its distance from the center of the imaging surface 22a increases. Therefore, in the row in which the focus detection area 100a is located, the focus detection areas 100 farthest from the optical axis OA1 of the photographing optical system 31 (having the highest image height H) are the focus detection areas 100b and 100c located at the left end (end in the −X direction) and right end (end in the +X direction) of the row. The focus detection areas 100 with the highest image height H in the image sensor 22 are the four focus detection areas 100 located at the corners of the image pickup surface 22a.

[0058] Note that, because the focus detection area 100 has a predetermined area, the image height varies for each focus detection pixel depending on its position within the focus detection area 100. Within the same focus detection area 100, the image height differs between the central small area 110a (see FIG. 2B) and the small areas 110b and 110c (see FIG. 2B) located at the left end (the end in the -X direction) and the right end (the end in the +X direction). However, in this embodiment, the value of the image height H at the center of one focus detection area 100 is used as the value of the image height of the entire focus detection area 100. The image height of the focus detection area 100a at the center of the imaging surface 22a is zero, and the image heights of the focus detection areas 100b and 100c are the predetermined image height H.

[0059] 1, the distance calculation unit 214 calculates the exit pupil distance of the photographing optical system 31 at the image height H. The distance calculation unit 214 calculates the exit pupil distance Po(H) of the photographing optical system 31 at the image height H of the focus detection area 100 set by the area setting unit 213 using a predetermined calculation formula. The predetermined calculation formula can be, for example, the following calculation formula (1), but may also be another calculation formula. Po(H)=h4×H ４ + h2 × H ２ +Co... (1)

[0060] Equation (1) is an equation with the image height H as a variable, where parameter (h4) is the coefficient of the fourth-order term of variable H, parameter (h2) is the coefficient of the second-order term of variable H, and constant term Co is the exit pupil distance at the position where the image height is zero (the position of the optical axis OA1 on the imaging plane 22a). The parameters (h4), (h2), and constant term Co are information regarding the exit pupil distance corresponding to different image heights, and are values ​​determined by the optical characteristics of the photographic optical system 31. Information indicating parameters (h4), (h2), and constant term Co is transmitted from the interchangeable lens 3 to the camera body 2 as lens information. Equation (1) is stored in an internal memory of the body control unit 21. The distance calculation unit 214 calculates the exit pupil distance Po(H) related to the image height H of the focus detection area 100 set by the area setting unit 213, based on the lens information (h4, h2, Co), and equation (1). The arithmetic formula (1) may be stored in an internal memory of the lens control unit 32. The lens control unit 32 may transmit the arithmetic formula (1) together with the parameters (h4), (h2) and the constant term Co from the interchangeable lens 3 to the camera body 2 as lens information.

[0061] The selection unit 215 selects which of the first to third AF pixel pairs PR1 to PR3 included in the pixel unit 221 to use for focus detection, output signals Sig1 and Sig2 from the AF pixel pair. In this embodiment, the selection unit 215 selects one type of AF pixel pair from the first to third AF pixel pairs PR1 to PR3 arranged in the focus detection area 100 set by the area setting unit 213. The selection unit 215 selects an AF pixel pair from the first to third AF pixel pairs PR1 to PR3 that is appropriate for the exit pupil distance Po(H) calculated by the distance calculation unit 214. Furthermore, when multiple focus detection areas 100 are set by the area setting unit 213, the selection unit 215 selects AF pixel pairs of the same type in each selected focus detection area 100.

[0062] The focus detection unit 216 performs focus detection processing required for automatic focus adjustment (AF) of the photographic optical system 31. The focus detection unit 216 calculates the defocus amount by a split-pupil phase difference detection method using signals Sig1 and Sig2 output from the AF pixel pair selected by the selection unit 215.

[0063] The focus detection unit 216 performs a correlation calculation between a first signal Sig1 generated by capturing an image formed by a first light beam that has passed through a first pupil region of the exit pupil of the photographing optical system 31 and a second signal Sig2 generated by capturing an image formed by a second light beam that has passed through a second pupil region, and calculates the amount of deviation between the image plane of the image formed by the photographing optical system 31 and the image plane 22a of the image sensor 22. The focus detection unit 216 converts this amount of deviation into a defocus amount based on a predetermined conversion formula.

[0064] Based on the defocus amount calculated by the focus detection unit 216, the position control unit 217 calculates the focus position of the focus lens 31b (the amount of movement of the focus lens 31b to the focus position) for the image from the shooting optical system 31 to be focused (formed) on the imaging surface 22a of the image sensor 22.

[0065] More specifically, the position control unit 217 determines whether the defocus amount is within a tolerance. If the defocus amount is within the tolerance, the position control unit 217 determines that the lens is in focus. On the other hand, if the defocus amount exceeds the tolerance, the position control unit 217 determines that the lens is not in focus, and sends a signal to the lens control unit 32 of the interchangeable lens 3 indicating the amount of movement of the focus lens 31b and an instruction to move the lens. The lens control unit 32 moves the focus lens 31b according to the amount of movement, thereby automatically adjusting the focus.

[0066] In this embodiment, the focus detection unit 216 can perform contrast detection focus detection in addition to phase difference detection focus detection. In this case, the position control unit 217 moves the focus lens 31b of the imaging optical system 31 along the optical axis OA1, while the focus detection unit 216 sequentially calculates the contrast evaluation value of the subject image based on signals output from the imaging pixels. The position control unit 217 associates the position of the focus lens 31b with the contrast evaluation value using position information of the focus lens 31b transmitted from the interchangeable lens 3. The position control unit 217 then detects the position of the focus lens 31b at which the contrast evaluation value reaches its peak, i.e., its maximum value, as the in-focus position. The position control unit 217 transmits information about the position of the focus lens 31b corresponding to the detected in-focus position to the lens control unit 32. The lens control unit 32 moves the focus lens 31b to the in-focus position to perform focus adjustment. In the following description, the operation in which the focus detection unit 216 sequentially calculates the contrast evaluation value of the subject image based on the signals output from the imaging pixels and detects the in-focus position while the position control unit 217 moves the focus lens 31b of the imaging optical system 31 in the optical axis OA1 direction may be referred to as a scanning operation. For example, if the defocus amount cannot be calculated using the signals Sig1 and Sig2 output from the AF pixel pair selected by the selection unit 215, the position control unit 217 starts a scanning operation after a predetermined time has elapsed to search for the in-focus position.

[0067] 6A and 6B are diagrams for explaining focus detection based on the signals Sig1 and Sig2 output from the AF pixel pair selected by the selection unit 215. FIG.

[0068] As described above, the focus detection unit 216 uses the signals Sig1 and Sig2 output from the AF pixel pair selected by the selection unit 215 to calculate the defocus amount by a split-pupil phase difference detection method.

[0069] 6A and 6B, it is assumed that the AF pixel pair selected by the selection unit 215 is the second AF pixel pair PR2. In Fig. 6A and 6B, the second pixel set 400-2 including the second AF pixel pair PR2 is indicated by hatching.

[0070] 6A, when a portion of the subject image SBJ overlaps with the second pixel set 400-2 including the second AF pixel pair PR2, the focus detection unit 216 can calculate the defocus amount using the signals Sig1 and Sig2 output from the second AF pixel pair PR2, provided that the subject image SBJ is not in a state of large blur. On the other hand, when the subject image SBJ does not overlap with the second pixel set 400-2 including the second AF pixel pair PR2, that is, when the subject image SBJ is in a region where the first pixel set 400-1 including the first AF pixel pair PR1 and the third pixel set 400-3 including the third AF pixel pair PR3, both of which are not selected by the selection unit 215, are continuous, the focus detection unit 216 cannot calculate the defocus amount using the signals Sig1 and Sig2 output from the second AF pixel pair PR2, even if the subject image SBJ is close to being in focus. In the following description, the area where a pixel group including an AF pixel pair not selected by the selection unit 215 is located may be referred to as a dead zone. In Figures 6(A) and 6(B), the non-hatched area is the dead zone, and is indicated by DZ.

[0071] The defocus amount cannot be calculated based on the signals Sig1 and Sig2 output from the AF pixel pair selected by the selection unit 215 in the following cases: (1) when the subject image is in a state of extreme blur, or (2) when the subject image is near the in-focus point but happens to be located in the dead zone.

[0072] In the case of (1) above, it is preferable to detect the in-focus position by a scanning operation (by moving the focus lens 31b), but in the case of (2) above, performing a scanning operation may result in losing sight of the subject.Furthermore, in the case of (2) above, scanning operations may occur frequently even when the subject image is close to being in focus, which may cause discomfort to the user.

[0073] Therefore, in this embodiment, when the defocus amount cannot be calculated based on the signals Sig1 and Sig2 output from the AF pixel pair selected by the selection unit 215, it is determined whether the case is (1) or (2) above, and the time until the start of the scanning operation is changed depending on the determination result.

[0074] 7 to 9 are flowcharts illustrating an example of processing executed by the body control unit 21. The processing in FIGS. 7 to 9 is executed when the shooting mode is "bird mode" or "airplane mode" and a predetermined subject (bird, airplane) is not detected, or when the shooting mode is "bird mode" or "airplane mode" and a predetermined subject (bird, airplane) is detected but the vertical (Y-direction) size of the subject image is equal to or smaller than a predetermined size. The predetermined size may be the vertical size of a pixel group (dead zone) that includes AF pixel pairs other than the AF pixel pair selected by the selection unit 215. In other words, the predetermined size may be the vertical (Y-direction) size of the area between the pixel group that includes the AF pixel pair selected by the selection unit 215 and another pixel group that is adjacent to the pixel group in the Y direction and includes the AF pixel pair selected by the selection unit 215.

[0075] 7, for example, when the user operates the operation unit 25 to set autofocus (AF) mode, the area setting unit 213 of the camera body 2 sets, as the area where focus detection is performed, the focus detection area 100 corresponding to the AF frame including the subject detected by the subject detection unit 212 (step S11). The image height of the focus detection area 100 set by the area setting unit 213 is set as the image height Hx. Note that if the subject detection unit 212 does not detect a specific subject, the focus detection area 100 corresponding to the AF frame according to the settings on the camera body 2 or the AF frame set by the user is set as the area where focus detection is performed.

[0076] Next, the distance calculation unit 214 of the camera body 2 calculates the exit pupil distance Pox for the image height Hx by substituting the image height Hx of the set focus detection area 100 into equation (1), which is determined by the constant term Po and coefficients h4 and h2 of the lens information (step S13). It is assumed that the constant term Po and coefficients h4 and h2 are stored, for example, in the lens memory 33 (or an internal memory of the lens control unit 32) and are transmitted to the camera body 2 from the interchangeable lens 3 when the camera body 2 is powered on. The camera body 2 stores the constant term Po and coefficients h4 and h2 received from the interchangeable lens 3 in, for example, an internal memory of the body control unit 21.

[0077] Next, the selection unit 215 determines whether the exit pupil distance Pox calculated by the distance calculation unit 214 is within a first exit pupil distance range (first range) (step S15). If the exit pupil distance Pox is within the first exit pupil distance range (step S15 / YES), the selection unit 215 selects the first AF pixel pair PR1 (step S17).

[0078] If the exit pupil distance Pox is not within the first exit pupil distance range (step S15 / NO), the selection unit 215 determines whether the exit pupil distance Pox is within the second exit pupil distance range (second range) (step S19).If the exit pupil distance Pox is within the second exit pupil distance range (step S19 / YES), the selection unit 215 selects the second AF pixel pair PR2 (step S21).

[0079] If the exit pupil distance Pox is not within the second exit pupil distance range (step S19 / NO), the selection unit 215 selects the third AF pixel pair PR3 (step S23).

[0080] Next, the focus detection unit 216 of the camera body 2 executes first focus detection (step S25). Specifically, the focus detection unit 216 performs a correlation operation on the signals Sig1 and Sig2 output from the AF pixel pair selected in step S17, S21, or S23 to calculate the amount of deviation between the image plane of the photographing optical system 31 and the imaging plane 22a of the image sensor 22, and converts the calculated amount of deviation into a defocus amount. The calculated defocus amount is stored in a volatile memory or the like provided in the body control unit 21 as a history of focus detection results.

[0081] Next, the focus detection unit 216 determines whether the release button (operation unit 25) is half-pressed (step S27). In this embodiment, half-pressing the release button corresponds to an instruction to perform focus detection of the photographing optical system 31.

[0082] If the release button is not half-pressed (step S27 / NO), the focus detection unit 216 performs second focus detection (step S29). Specifically, the focus detection unit 216 performs a correlation operation on the signals Sig1 and Sig2 from one of the AF pixel pairs not selected by the selection unit 215 to calculate the amount of deviation between the image plane of the photographing optical system 31 and the imaging surface 22a of the image sensor 22, and converts the calculated amount of deviation into a defocus amount. For example, if the AF pixel pair selected by the selection unit 215 is the second AF pixel pair PR2, the focus detection unit 216 performs a correlation operation on the signals Sig1 and Sig2 from one of the first AF pixel pair PR1 and the third AF pixel pair PR3 (e.g., the third AF pixel pair PR3) to calculate the amount of deviation between the image plane of the photographing optical system 31 and the imaging surface 22a of the image sensor 22, and converts the calculated amount of deviation into a defocus amount. The calculated defocus amount is stored in a volatile memory or the like provided in the body control unit 21 as a history of focus detection results.

[0083] Next, the focus detection unit 216 determines whether the release button has been half-pressed (step S31). If the release button has not been half-pressed (step S31 / NO), the focus detection unit 216 performs first focus detection (step S33). That is, the focus detection unit 216 performs a correlation operation on the signals Sig1 and Sig2 from the AF pixel pair selected by the selection unit 215 to calculate the amount of deviation between the image plane of the photographing optical system 31 and the image plane 22a of the image sensor 22, and converts the calculated amount of deviation into a defocus amount. The calculated defocus amount is stored in a volatile memory or the like provided in the body control unit 21 as a history of focus detection results.

[0084] Next, the focus detection unit 216 determines whether the release button has been half-pressed (step S35). If the release button has not been half-pressed (step S35 / NO), the focus detection unit 216 performs third focus detection (step S37). Specifically, the focus detection unit 216 performs a correlation operation on the signals Sig1 and Sig2 from the other AF pixel pair of the AF pixel pairs not selected by the selection unit 215, calculates the amount of deviation between the image plane of the photographing optical system 31 and the imaging surface 22a of the image sensor 22, and converts the calculated amount of deviation into a defocus amount. For example, if the AF pixel pair selected by the selection unit 215 is the second AF pixel pair PR2, a correlation operation is performed on the signals Sig1 and Sig2 from the other of the first AF pixel pair PR1 and the third AF pixel pair PR3 (for example, the first AF pixel pair PR1) to calculate the amount of deviation between the image plane of the photographing optical system 31 and the imaging plane 22a of the image sensor 22, and the calculated amount of deviation is converted into a defocus amount. The calculated defocus amount is stored in a volatile memory or the like provided in the body control unit 21 as a history of focus detection results.

[0085] Next, the focus detection unit 216 determines whether the release button has been half-pressed (step S39). If the release button has not been half-pressed (step S39 / NO), the process returns to step S25. In this manner, the focus detection unit 216 repeats the processes of steps S25 to S39 until the release button is half-pressed. Since the focus detection unit 216 alternately performs focus detection based on the signal of the AF pixel pair selected by the selection unit 215 and focus detection based on the signal of the AF pixel pair other than the AF pixel pair selected by the selection unit 215, the control unit 222 of the image sensor 22 alternately outputs the signal of the AF pixel pair selected by the selection unit 215 and the signal of the AF pixel pair other than the AF pixel pair selected by the selection unit 215.

[0086] Fig. 10 is a diagram schematically illustrating the processing executed by the body control unit 21. Fig. 10 shows a case where the second AF pixel pair PR2 is selected by the selection unit 215. As shown in Fig. 10, the focus detection unit 216 alternately performs focus detection based on the signals Sig1, Sig2 from the second AF pixel pair PR2 and focus detection based on the signals Sig1, Sig2 from either the first AF pixel pair PR1 or the third AF pixel pair PR3, until the release button is half-pressed.

[0087] 7 , when the release button is half-pressed (YES in step S27, YES in step S31, YES in step S35, or YES in step S39), the position control unit 217 sets a period T0 as a waiting time (step S40). The waiting time is the time until the scanning operation starts when the defocus amount cannot be calculated based on the signals Sig1 and Sig2 from the AF pixel pair selected by the selection unit 215. The period T0 is, for example, 0 seconds.

[0088] Next, the focus detection unit 216 performs first focus detection (step S43). In this embodiment, when the release button is half-pressed, that is, when an instruction to perform focus detection of the photographing optical system 31 is received, focus detection is performed using the AF pixel pair selected by the selection unit 215 in order to accurately calculate the defocus amount. That is, in this embodiment, after the release button is half-pressed, the focus detection unit 216 performs only first focus detection. Therefore, after the release button is half-pressed, the control unit 222 of the image sensor 22 outputs a signal of the AF pixel pair selected by the selection unit 215.

[0089] Next, the position control unit 217 determines whether or not the defocus amount has been calculated in the first focus detection of step S43 (step S45). If the defocus amount has been calculated (step S45 / YES), the position control unit 217 calculates the in-focus position of the focus lens 31b (the amount of movement of the focus lens 31b to the in-focus position) based on the defocus amount, and transmits the amount of movement of the focus lens 31b and a signal instructing lens movement to the lens control unit 32 of the interchangeable lens 3 (focus lens drive instruction) (step S77).

[0090] Next, the focus detection unit 216 determines whether the half-press of the release button has been released (step S79). If the half-press of the release button has been released (step S79 / YES), the process returns to step S11.

[0091] If the half-press of the release button is not released (step S79 / NO), the focus detection unit 216 determines whether the release button is fully pressed (step S81). In this embodiment, fully pressing the release button indicates an instruction to capture an image (record a still image).

[0092] 7 to 9 are ended, and the body control unit 21 executes a predetermined imaging process. If the release button is not fully pressed (step S81 / NO), the process returns to step S40.

[0093] If the defocus amount cannot be calculated in the first focus detection of step S43 (NO in step S45), the position control unit 217 determines whether the defocus amount was calculated in any of the multiple focus detections performed immediately before the first focus detection of step S43 (step S47). For example, suppose that the release button is half-pressed at the timing indicated by the arrow in FIG. 10, and the defocus amount was not calculated in the first focus detection performed after the release button was half-pressed (focus detection based on the signals Sig1 and Sig2 from the second AF pixel pair PR2 selected by the selection unit 215). In this case, it is determined whether the defocus amount was calculated in any of the four focus detections performed immediately before that (indicated by dashed dotted lines).

[0094] 10 , in the first focus detection performed after the release button is half-pressed, the subject image SBJ is located in the dead zone, so the second pixel set 400-2 including the second AF pixel pair PR2 selected by the selection unit 215 does not overlap with the subject image SBJ, and the defocus amount is not calculated. On the other hand, before the release button is half-pressed, a portion of the subject image SBJ overlaps with the first pixel set 400-1 including the first AF pixel pair PR1 and the third pixel set 400-3 including the third AF pixel pair PR3. Therefore, if the subject image SBJ is not in a state of extreme blur (if the subject image SBJ is near the in-focus point), the defocus amount can be calculated. Therefore, if the defocus amount can be calculated in any of the multiple focus detections performed immediately before the first focus detection in step S43, it can be determined that the subject image simply happened to be located in the dead zone when the first focus detection in step S43 was performed.

[0095] Therefore, if the defocus amount has been calculated in one of the multiple focus detections performed immediately before the first focus detection in step S43 (YES in step S47), the waiting time until the start of the scanning operation is set to period T1, which is longer than period T0 (step S49). Period T1 is, for example, 200 msec. This is because if the subject happens to be located in the dead zone, it is highly likely that the defocus amount can be calculated in the first focus detection (focus detection based on the signal of the selected AF pixel pair) that is repeatedly performed during the waiting time, so the scanning operation is not immediately performed.

[0096] Next, the focus detection unit 216 determines whether the half-press of the release button has been released (step S51). If the half-press of the release button has been released (step S51 / YES), the process returns to step S11. If the half-press of the release button has not been released (step S51 / NO), the focus detection unit 216 determines whether the release button has been fully pressed (step S53).

[0097] 7 to 9 are ended, and the body control unit 21 executes a predetermined image capture process. Although the defocus amount could not be calculated in step S43, the defocus amount was calculated in one of the multiple focus detections executed immediately before the first focus detection in step S43. Therefore, the subject image SBJ is close to being in focus, and it is considered that there is no problem in executing the image capture process. Note that the body control unit 21 may execute the image capture process after the scan operation.

[0098] If the release button is not fully pressed (step S53 / NO), the focus detection unit 216 executes first focus detection (step S55).

[0099] Next, the position control unit 217 determines whether the defocus amount has been calculated in the first focus detection in step S55 (step S57). If the defocus amount has been calculated (step S57 / YES), the process proceeds to step S77. The process from step S77 onwards is the same as the process described above, and therefore a description thereof will be omitted.

[0100] If the defocus amount cannot be calculated in the first focus detection of step S55 (NO in step S57), the position control unit 217 determines whether the subject's movement direction is the first direction (step S59). Here, the first direction refers to a direction intersecting the arrangement direction (X direction) of the pixel group including the AF pixel pair selected by the selection unit 215. When the focus detection unit 216 performs first focus detection at a predetermined time interval, even if the subject image is located in a dead zone in the first focus detection of step S43, if the subject's movement direction is the first direction, the pixel group including the AF pixel pair selected by the selection unit 215 and the subject image are considered to overlap in the first focus detection of step S55. The first direction is, for example, a direction whose angle with the vertical direction (Y direction) is within a range of ±45°. The subject's movement direction (motion vector) is detected for each frame.

[0101] If the subject is moving in the first direction (step S59 / YES), the position control unit 217 sets the waiting time before starting the scanning operation to period T2, which is shorter than period T1 (step S61). Period T2 may be longer than period T0 or the same as period T0, as long as it is closer than period T1. If the subject is moving in the first direction, the pixel set including the AF pixel pair selected by the selection unit 215 in the first focus detection in step S55 is likely to overlap with the subject image, but the defocus amount cannot be calculated in step S55. Therefore, if the defocus amount cannot be calculated in step S55 and the subject is moving in the first direction, the waiting time before starting the scanning operation is shortened.

[0102] If the moving direction of the subject is not the first direction (step S59 / NO), the process of step S61 is skipped.

[0103] Next, the focus detection unit 216 determines whether the half-pressed release button has been released (step S63). If the half-pressed release button has been released (step S63 / YES), the process returns to step S11. If the half-pressed release button has not been released (step S63 / NO), the focus detection unit 216 determines whether the release button has been fully pressed (step S65).

[0104] 7 to 9 ends, and the body control unit 21 executes a predetermined image capture process. Note that the body control unit 21 may execute the image capture process after the scanning operation, for example.

[0105] If the release button is not pressed all the way down (step S65 / NO), the position control unit 217 determines whether the time elapsed since the release button was pressed halfway down has exceeded the standby time (step S67). Note that the position control unit 217 may also determine whether the time elapsed since step S43 was executed has exceeded the standby time.

[0106] If the elapsed time does not exceed the waiting time (step S67 / NO), the process returns to step S55. On the other hand, if the elapsed time exceeds the waiting time (step S67 / YES), the position control unit 217 executes a scan operation (step S69). After step S69 is completed, the process returns to step S40.

[0107] In step S47 of FIG. 8, if the defocus amount cannot be calculated in any of the multiple focus detections performed immediately before the first focus detection in step S43 (step S47 / NO), it is highly likely that the subject image is in a highly blurred state and therefore the defocus amount cannot be calculated for any of the first to third AF pixel pairs PR1 to PR3. Therefore, if the determination in step S47 is NO, the process proceeds to step S67, where the position control unit 217 determines whether the elapsed time has exceeded the waiting time. The waiting time in this case is period T0, e.g., 0 seconds. If the elapsed time has exceeded the waiting time (step S67 / YES), the position control unit 217 executes a scan operation (step S69) and returns to step S40. This allows the focus lens 31b to be positioned near the in-focus position.

[0108] As described above, during the scanning operation, the position control unit 217 moves the focus lens 31b of the imaging optical system 31 along the optical axis OA1, while the focus detection unit 216 sequentially calculates the contrast evaluation value of the subject image based on the signals output from the imaging pixels. Driving the focus lens 31b from the close-up end to the infinity end takes time for the scanning operation. Therefore, in this embodiment, the driving range of the focus lens 31b during the scanning operation is limited, thereby reducing the time required for the scanning operation.

[0109] Specifically, during the scanning operation, the subject detection unit 212 sequentially calculates the reliability that the detected subject is a predetermined subject (for example, a bird or an airplane). Then, the position control unit 217 limits the range in which the focus lens 31b is driven based on the relationship between the position of the focus lens 31b and the reliability at that position of the focus lens 31b.

[0110] Fig. 11 is a graph showing an example of the relationship between the position of the focus lens 31b and the reliability calculated by the subject detection unit 212. The subject detection unit 212 calculates the reliability of the pupils of the detected subject, the reliability of the faces of the detected subjects, and the reliability of the entire detected subjects, and Fig. 11 shows the reliability of the pupils of the detected subject and the reliability of the faces of the detected subjects.

[0111] 11, when the focus lens 31b is moved from the close-up end toward the infinity end, the reliability of the subject's pupil drops sharply near position P1 and becomes low at position P2. The reliability of the subject's face increases sharply near position P3 and drops sharply near position P4, reaching a maximum value between positions P3 and P4.

[0112] For example, the position control unit 217 moves the focus lens 31b from the closest end toward the infinity end. When the focus lens 31b reaches position P2, where the reliability for the subject's pupil is low, the position control unit 217 prevents the focus lens 31b from moving further toward infinity than position P2. That is, the section SC1 from the closest end to position P2 is the section in which the focus lens 31b is driven during the scanning operation. Alternatively, the position control unit 217 moves the focus lens 31b from the closest end toward the infinity end. When the focus lens 31b reaches position P5, where the reliability for the subject's face is convex, the position control unit 217 prevents the focus lens 31b from moving further toward infinity than position P5. Furthermore, when the focus lens 31b is moved from position P5 toward the closest end, if the focus lens 31b reaches position P6, where the reliability for the subject's face is convex, the position control unit 217 prevents the focus lens 31b from moving further toward infinity than position P6. In other words, the section SC2 including the section where the reliability of the subject's face is convex is set as the section where the focus lens 31b is driven in the scanning operation. This makes it possible to reduce the time required for the scanning operation compared to when the focus lens 31b is moved from the close end to the infinity end until the driving range of the focus lens 31b is limited.

[0113] As described above in detail, according to this embodiment, the image sensor 22 is equipped with a first AF pixel pair PR1, a second AF pixel pair PR2, and a third AF pixel pair PR3 that photoelectrically convert light that has passed through the photographing optical system 31 and output signals Sig1, Sig2 that are used for focus detection of the photographing optical system 31, and a control unit 222 that performs a first control that alternately outputs the signals Sig1, Sig2 of an AF pixel pair selected from the first to third AF pixel pairs PR1 to PR3 and the signals Sig1, Sig2 of an AF pixel pair other than the selected AF pixel pair, and a second control that outputs the signals Sig1, Sig2 of an AF pixel pair selected from the first to third AF pixel pairs PR1 to PR3. This makes it possible to perform focus detection based on the signals Sig1, Sig2 of the selected AF pixel pair and focus detection based on the signals Sig1, Sig2 of AF pixel pairs other than the selected AF pixel pair while the first control is being performed.

[0114] Furthermore, in this embodiment, the control unit 222 performs the first control before receiving an instruction to perform focus detection of the photographing optical system 31 (before the release button is half-pressed), and performs the second control after receiving the instruction. This allows focus detection based on the signals Sig1 and Sig2 of the selected AF pixel pair to be performed after the release button is half-pressed, thereby enabling focus detection (calculation of the defocus amount) to be performed with high accuracy. Furthermore, the result of focus detection based on the signals Sig1 and Sig2 of the selected AF pixel pair performed before the release button is half-pressed and the result of focus detection based on the signals Sig1 and Sig2 of AF pixel pairs other than the selected AF pixel pair can be used for control after the release button is half-pressed.

[0115] Furthermore, according to this embodiment, the focus detection device 4 includes an image sensor 22 having a first AF pixel pair PR1, a second AF pixel pair PR2, and a third AF pixel pair PR3 that photoelectrically convert light that has passed through the photographing optical system 31 and output signals Sig1, Sig2 used for focus detection of the photographing optical system 31, a focus detection unit 216 that performs focus detection of the photographing optical system 31 based on at least one of the signals Sig1, Sig2 from the first AF pixel pair PR1, the signals Sig1, Sig2 from the second AF pixel pair PR2, and the signals Sig1, Sig2 from the third AF pixel pair PR3, and a position control unit 217 that controls the position of the photographing optical system 31 (focus lens 31b). If the focus detection unit 216 has successfully detected the focus of the photographing optical system 31, the position control unit 217 controls the position of the photographing optical system 31 after a period T1 (e.g., 200 msec) has elapsed since the focus detection unit 216 received an instruction to perform focus detection of the photographing optical system 31. If the focus detection unit 216 has not successfully detected the focus of the photographing optical system 31, the position control unit 217 controls the position of the photographing optical system 31 after a period T0 (e.g., 0 sec) that is shorter than the period T1 has elapsed since the focus detection unit 216 received an instruction to perform focus detection of the photographing optical system 31. As a result, if the focus detection unit 216 has successfully detected the focus of the photographing optical system 31, the position of the photographing optical system 31 is not controlled until a period T1 that is longer than the period T0 has elapsed, even if the focus detection unit 216 receives an instruction to perform focus detection of the photographing optical system 31. This makes it possible to prevent the position of the photographing optical system 31 from changing and the subject from being lost, even if the focus detection of the photographing optical system 31 has been successfully performed.

[0116] Furthermore, in this embodiment, if the focus detection unit 216 was able to detect the focus of the photographing optical system 31 before receiving an instruction to perform focus detection of the photographing optical system 31, the position control unit 217 controls the position of the photographing optical system 31 after the lapse of the period T1, and if the focus detection unit 216 was not able to detect the focus of the photographing optical system 31 before receiving an instruction to perform focus detection of the photographing optical system 31, the position control unit 217 controls the position of the photographing optical system 31 after the lapse of the period T0. This makes it possible to prevent a situation in which, even if the focus detection unit 216 was able to detect the focus of the photographing optical system 31 before receiving an instruction to perform focus detection of the photographing optical system 31, the position of the photographing optical system 31 is changed and the subject is lost because, for example, the focus detection unit 216 is unable to detect the focus of the photographing optical system 31 because the subject image is located in a dead zone after receiving an instruction to perform focus detection of the photographing optical system 31. Furthermore, if the focus detection unit 216 is unable to detect the focus of the photographing optical system 31 before receiving an instruction to perform focus detection of the photographing optical system 31, it is considered that the subject image is in a state of great blur, and therefore the state of great blur can be resolved early by controlling the position of the photographing optical system 31 after a period T0 shorter than the period T1 has elapsed.

[0117] Furthermore, in this embodiment, if the focus detection unit 216 is able to detect the focus of the photographing optical system 31 (if the defocus amount is able to be calculated) during period T1, the position control unit 217 controls the position of the photographing optical system 31 based on the detection result of the focus detection unit 216. As a result, even if the subject happens to be located in the dead zone, if the subject image overlaps with the pixel group including the selected AF pixel pair within period T1, the focus lens 31b can be moved to the in-focus position.

[0118] Furthermore, in this embodiment, the image sensor 22 includes imaging pixels 13 that photoelectrically convert light transmitted through the photographing optical system 31 and output imaging signals used to generate an image, and the position control unit 217 controls the position of the photographing optical system 31 to detect the focus state of the photographing optical system 31, and changes the range in which the position of the photographing optical system 31 is controlled based on the relationship between the position of the photographing optical system 31 in the optical axis direction and the reliability of a predetermined subject detected in an image generated based on the imaging signals of the imaging pixels 13. As a result, when performing a scanning operation, the time required for the scanning operation can be shortened compared to when the focus state of the photographing optical system 31 is detected by moving the photographing optical system 31 from the close end to the infinity end.

[0119] Furthermore, when the movement direction of a predetermined subject detected in an image generated based on the imaging signals of the imaging pixels 13 is the first direction, the position control unit 217 controls the position of the imaging optical system 31 after a period T3, which is shorter than the period T1, has elapsed since the instruction to perform focus detection of the imaging optical system 31 was received. This makes it possible to change the timing of executing the scanning operation based on whether the subject image is in a large blur state or whether the subject is located in a dead zone.

[0120] Furthermore, according to this embodiment, the camera 1 is equipped with an image sensor 22 having a first AF pixel pair PR1, a second AF pixel pair PR2, and a third AF pixel pair PR3 that photoelectrically convert light incident through the photographing optical system 31 having a focus lens 31 b and output signals Sig1, Sig2 used for focus detection, and an image pickup pixel 13 that photoelectrically converts light incident through the photographing optical system 31 and outputs an image pickup signal used for image generation, a focus detection unit 216 that performs focus detection of the photographing optical system 31 based on the signals Sig1, Sig2 output from at least one of the first AF pixel pair PR1, the second AF pixel pair PR2, and the third AF pixel pair PR3, and a position control unit 217 that performs a scanning operation to sequentially calculate an evaluation value for the contrast of an image formed by the photographing optical system 31 based on the image pickup signal while moving the focus lens 31 b in the optical axis direction. The focus detection unit 216 alternately performs first focus detection, which performs focus detection based on signals Sig1 and Sig2 output from a selected AF pixel pair, and second focus detection, which performs focus detection based on signals Sig1 and Sig2 output from AF pixel pairs other than the selected AF pixel pair, until receiving an instruction to perform focus detection of the photographic optical system 31. After receiving an instruction to perform focus detection of the photographic optical system 31, the focus detection unit 216 performs first focus detection, which performs focus detection based on signals Sig1 and Sig2 output from the selected AF pixel pair. The position control unit 217 performs a scanning operation when a period during which focus detection is not possible in the first focus detection performed after receiving an instruction to perform focus detection has elapsed, the period being determined based on the results of focus detection at the first and second focus detection foci performed before receiving the instruction. This prevents frequent scanning operations.

[0121] (Modification) In the above embodiment, when the release button is half-pressed (step S27 / YES, step S31 / YES, step S35 / YES, or step S39 / YES), the position control unit 217 calculates the in-focus position of the focus lens 31b based on the defocus amount calculated based on the signals Sig1 and Sig2 from the AF pixel pair selected by the selection unit 215. However, this is not limited to this. For example, a defocus amount calculated based on the signals Sig1 and Sig2 of an AF pixel pair other than the AF pixel pair selected by the selection unit 215 may be used to calculate the in-focus position of the focus lens 31b, depending on the image height Hx of the focus detection area 100. That is, depending on the image height Hx of the focus detection area 100, even after the release button is half-pressed, focus detection based on the signals Sig1, Sig2 of an AF pixel pair selected from the first to third AF pixel pairs PR1 to PR3 and focus detection based on the signals Sig1, Sig2 of an AF pixel pair other than the selected AF pixel pair may be performed alternately.

[0122] 12 to 16 are flowcharts showing an example of processing executed by the body control unit 21 according to the modified example. The modified example differs from the example of processing executed by the body control unit 21 according to the embodiment in that, between steps S40 and S43 in the embodiment, a determination is made as to whether or not the image height of the focus detection area 100 is less than a threshold value (step S41).

[0123] When the image height Hx of the focus detection area 100 is equal to or greater than the threshold value (FIG. 13: step S41 / NO), the processing is the same as in the above-described embodiment, and therefore the same processes are denoted by the same symbols and detailed explanations are omitted.

[0124] If the image height Hx of the focus detection area 100 is less than the threshold value (step S41 / YES), that is, if the focus detection area 100 is within a predetermined area including the center of the imaging surface 22a, it is considered possible to calculate a defocus amount with sufficient accuracy even if the signals Sig1 and Sig2 of the AF pixel pair not selected by the selection unit 215 are used.

[0125] Therefore, in the modified example, if the image height Hx of the focus detection area 100 is less than the threshold value (step S41 / YES), the focus detection unit 216 performs not only the first focus detection but also the second focus detection and the third focus detection.

[0126] In this modified example, if the image height Hx of the focus detection area 100 is less than the threshold value (step S41 / YES), the focus detection unit 216 first executes the first focus detection (step S101).

[0127] Next, the position control unit 217 determines whether or not the defocus amount was calculated in step S101 (step S103). If the defocus amount could not be calculated (step S103 / NO), the focus detection unit 216 determines whether or not the half-press of the release button has been released (step S105).

[0128] If the release button is released from the halfway press (step S105 / YES), the process returns to step S11. If the release button is not released from the halfway press (step S105 / NO), the focus detection unit 216 determines whether the release button is fully pressed (step S107).

[0129] 12 to 16 ends, and the body control unit 21 executes a predetermined image capture process. If the release button is not fully pressed (step S107 / NO), the focus detection unit 216 executes second focus detection (step S109).

[0130] Next, the position control unit 217 determines whether or not the defocus amount was calculated in step S109 (step S111). If the defocus amount could not be calculated (step S111 / NO), the focus detection unit 216 determines whether or not the half-press of the release button has been released (step S113).

[0131] If the release button is released from the halfway press (step S113 / YES), the process returns to step S11. If the release button is not released from the halfway press (step S113 / NO), the focus detection unit 216 determines whether the release button is fully pressed (step S115).

[0132] 12 to 16 ends, and the body control unit 21 executes a predetermined image capture process. If the release button is not fully pressed (step S115 / NO), the focus detection unit 216 executes first focus detection (step S117).

[0133] Next, the position control unit 217 determines whether or not the defocus amount was calculated in step S117 (step S119). If the defocus amount could not be calculated (step S119 / NO), the focus detection unit 216 determines whether or not the half-press of the release button has been released (step S121).

[0134] If the release button is released from the halfway press (step S121 / YES), the process returns to step S11. If the release button is not released from the halfway press (step S121 / NO), the focus detection unit 216 determines whether the release button is fully pressed (step S123).

[0135] 12 to 16 ends, and the body control unit 21 executes a predetermined image capture process. If the release button is not fully pressed (step S123 / NO), the focus detection unit 216 executes a third focus detection (step S125).

[0136] Next, the position control unit 217 determines whether the defocus amount was calculated in step S125 (step S127). If the defocus amount could not be calculated (step S127 / NO), it means that the defocus amount could not be calculated using any of the first AF pixel pair PR1, the second AF pixel pair PR2, and the third AF pixel pair PR3. In this case, the subject image is highly blurred, and it is highly likely that the defocus amount could not be calculated. Therefore, if the defocus amount could not be calculated in step S125 (step S127 / NO), the position control unit 217 executes a scan operation (step S129) and returns to step S40.

[0137] On the other hand, if the defocus amount can be calculated in any of step S103, step S111, step S119, or step S127 (step S103 / YES, step S111 / YES, step S119 / YES, step S127 / YES), the position control unit 217 calculates the in-focus position of the focus lens 31b based on the calculated defocus amount and instructs the focus lens 31b to be driven (step S131).

[0138] Next, the focus detection unit 216 determines whether the half-pressed release button has been released (step S133). If the half-pressed release button has been released (step S133 / YES), the process returns to step S11. If the half-pressed release button has not been released (step S133 / NO), the focus detection unit 216 determines whether the release button has been fully pressed (step S135).

[0139] 12 to 16 ends, and the body control unit 21 executes a predetermined image capture process. If the release button is not pressed fully (step S135 / NO), the process returns to step S101.

[0140] 17 is a diagram showing a schematic diagram of the processing of steps S101 to S135. In FIG. 17, it is assumed that the second AF pixel pair PR2 is the AF pixel pair selected by the selector 215.

[0141] 17 , until the release button is half-pressed, the position control unit 217 alternately performs focus detection based on the signals Sig1 and Sig2 from the second AF pixel pair PR2 and focus detection based on the signals Sig1 and Sig2 from one of the first AF pixel pair PR1 and the third AF pixel pair PR3. If the image height Hx of the focus detection area 100 is less than the threshold, the position control unit 217 continues the process of alternately performing focus detection based on the signals Sig1 and Sig2 from the second AF pixel pair PR2 and focus detection based on the signals Sig1 and Sig2 from one of the first AF pixel pair PR1 and the third AF pixel pair PR3, even after the release button is half-pressed. 17 , when the defocus amount can be calculated based on the signals Sig1 and Sig2 from the third AF pixel pair PR3 indicated by the dashed dotted line and the signals Sig1 and Sig2 from the first AF pixel pair PR1, the position control unit 217 calculates the in-focus position of the focus lens 31b based on the defocus amount and instructs the focus lens 31b to be driven. This makes it possible to bring the subject image into focus even when the defocus amount cannot be calculated based on the signals Sig1 and Sig2 from the AF pixel pair selected by the selection unit 215.

[0142] In the above-described embodiment and modified example, the control unit 222 of the image sensor 22 alternately outputs the signals Sig1 and Sig2 of an AF pixel pair selected from among the first to third AF pixel pairs PR1 to PR3 and the signals Sig1 and Sig2 of an AF pixel pair other than the selected AF pixel pair. However, this is not limited to this. For example, if it is possible to simultaneously output the signals Sig1 and Sig2 of an AF pixel pair selected from among the first to third AF pixel pairs PR1 to PR3 and the signals Sig1 and Sig2 of an AF pixel pair other than the selected AF pixel pair, they may be output simultaneously. In this case, the focus detection unit 216 of the body control unit 21 performs focus detection using the signals Sig1 and Sig2 output from the appropriate AF pixel pair from among the signals Sig1 and Sig2 output from each of the first to third AF pixel pairs PR1 to PR3.

[0143] Furthermore, in the above embodiment and modified example, each focus detection area 100 is provided with a first pixel set 400-1, a second pixel set 400-2, and a third pixel set 400-3, but it is sufficient that at least two pixel sets are provided among the first to third pixel sets 400-1 to 400-3.

[0144] In the above-described embodiment and modified examples, the processes of FIGS. 7 to 9 or the processes of FIGS. 12 to 16 are executed when the shooting mode is "bird mode" or "airplane mode" and a predetermined subject (bird, airplane) is not detected, or when the shooting mode is "bird mode" or "airplane mode" and a predetermined subject (bird, airplane) is detected but the vertical (Y-direction) size of the subject image is equal to or smaller than a predetermined size. However, this is not limited to this. For example, regardless of the shooting mode, the processes of FIGS. 7 to 9 or the processes of FIGS. 12 to 16 may be executed when the vertical size of the subject image is equal to or smaller than a predetermined size, when the subject is small, or when the subject is a small object. Furthermore, the processes of FIGS. 7 to 9 or the processes of FIGS. 12 to 16 may be executed when the shooting mode is "small object mode" in addition to "bird mode" and "airplane mode."

[0145] Furthermore, in the above embodiments and variations, if the shooting mode is a specific one (e.g., bird mode, airplane mode, small object mode) in which the subject may be a small object, or if the subject is determined to be a small object during subject detection by the subject detection unit 212, the waiting time before proceeding to the scanning operation may be extended.

[0146] Furthermore, in the above embodiment and modified examples, when the shooting mode is "bird mode" or "airplane mode," the control unit 222 of the image sensor 22 performs the first control before the release button is half-pressed and performs the second control after the release button is half-pressed, but the control performed by the control unit 222 in other shooting modes is not limited to this and can be set as appropriate. For example, when the shooting mode is a mode other than "bird mode," "airplane mode," or "small object mode," such as a "portrait mode" suitable for photographing people, the control unit 222 can perform the second control without switching between the first control and the second control before and after the release button is half-pressed.

[0147] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this and can be modified in various ways without departing from the spirit of the present invention.

[0148] REFERENCE SIGNS LIST 1 camera 2 camera body 3 interchangeable lens 4 focus detection device 11, 12 focus detection pixel 13 imaging pixel 21 body control unit 22 imaging element 25 operation unit 31 photographing optical system 31b focus lens 216 focus detection unit 217 position control unit 222 control unit PR1 first AF pixel pair PR2 second AF pixel pair PR3 third AF pixel pair Sig1, Sig2 signals

Claims

1. An image sensor comprising: a first pixel and a second pixel, each having a pair of photoelectric conversion units that receive light beams passing through different pupil regions of an exit pupil of an optical system, and outputting a signal used for focus detection of the optical system; and a control unit that performs a first control to output both a signal of a selected one of the first pixel and the second pixel and a signal of the other of the first pixel and the second pixel, and a second control to output the signal of the one of the first pixel and the second pixel.

2. The image sensor according to claim 1, wherein the control unit performs the second control after receiving an instruction to perform focus detection of the optical system.

3. The image sensor according to claim 1 or 2, wherein the control unit performs the first control before receiving an instruction to perform focus detection of the optical system.

4. The imaging element according to claim 1, wherein the control unit, in the first control, alternately outputs a signal from the one pixel and a signal from the other pixel.

5. An imaging element according to any one of claims 1 to 4, wherein the control unit, in the second control, outputs a signal of a pixel selected based on information of the optical system.

6. An imaging element as described in any one of claims 1 to 5, wherein the control unit performs the first control and the second control in a first imaging mode for capturing an image of a specific subject, and performs the second control in a second imaging mode different from the first imaging mode.

7. An imaging element as described in any one of claims 1 to 6, wherein the pair of photoelectric conversion units includes a first photoelectric conversion unit that receives a light beam that passes through a first pupil region of an exit pupil of the optical system, and a second photoelectric conversion unit that receives a light beam that passes through a second pupil region of the exit pupil of the optical system, and a light receiving area of ​​the first photoelectric conversion unit of the first pixel is different from a light receiving area of ​​the first photoelectric conversion unit of the second pixel.

8. The image sensor according to claim 7, wherein the first pixel has a first light-shielding portion that blocks a portion of the light beam from the optical system, and the second pixel has a second light-shielding portion that blocks a portion of the light beam from the optical system and has an area different from that of the first light-shielding portion.

9. An image sensor as described in any one of claims 1 to 8, wherein the first pixel includes a first pixel pair that receives a light beam that passes through different pupil regions of an exit pupil of the optical system, and the second pixel includes a second pixel pair that receives a light beam that passes through different pupil regions of an exit pupil of the optical system.

10. An imaging device comprising: an imaging element according to any one of claims 1 to 9; and a generation unit that generates image data based on a signal output from the imaging element.

11. A focus detection device comprising: an imaging unit having a first pixel and a second pixel, each having a pair of photoelectric conversion units that receive light beams passing through different pupil regions of an exit pupil of an optical system; a detection unit that performs focus detection of the optical system based on each of the signals of the first pixel and the second pixel; a selection unit that selects one of the first pixel and the second pixel; and a control unit that controls a position of the optical system, wherein the control unit controls the position of the optical system after a first period has elapsed since receiving an instruction to perform focus detection of the optical system if the detection unit is unable to perform focus detection of the optical system based on the signal of one of the first pixel and the second pixel, but is able to perform focus detection of the optical system based on the signal of the other of the first pixel and the second pixel, and controls the position of the optical system after a second period shorter than the first period has elapsed since receiving an instruction to perform focus detection of the optical system if the detection unit is unable to perform focus detection of the optical system based on either the signal of the first pixel or the signal of the second pixel.

12. The focus detection device of claim 11, wherein the control unit controls the position of the optical system after the first period has elapsed if the detection unit is able to perform focus detection of the optical system based on the signal of the other pixel before receiving an instruction to perform focus detection of the optical system, and controls the position of the optical system after the second period has elapsed if the detection unit is unable to perform focus detection of the optical system based on the signal of the other pixel before receiving an instruction to perform focus detection of the optical system.

13. The focus detection device according to claim 11 or claim 12, wherein the control unit controls the position of the optical system based on the detection result of the detection unit when the detection unit is able to detect the focus of the optical system based on the signal of the one of the pixels during the first period.

14. A focus detection device as described in any one of claims 11 to 13, wherein the detection unit detects the amount of deviation between an image plane created by the optical system and an imaging plane of the imaging unit based on each of the signals of the first pixel and the second pixel.

15. A focus detection device as described in any one of claims 11 to 14, wherein the imaging unit includes a third pixel that photoelectrically converts light that has passed through the optical system and outputs a signal used to generate an image, and the control unit changes the range in which the position of the optical system is controlled based on a subject detected in an image generated based on the signal of the third pixel.

16. The focus detection device according to claim 15, wherein the control unit changes a range for controlling the position of the optical system based on the position of the optical system and the reliability of the detected subject.

17. A focus detection device as described in claim 15 or claim 16, wherein the control unit controls the position of the optical system after a third period shorter than the first period has elapsed since receiving an instruction to perform focus detection of the optical system when the movement direction of a specific subject detected in an image generated based on the signal of the third pixel is a direction that intersects the horizontal direction.

18. A focus detection device as described in any one of claims 11 to 17, wherein the pair of photoelectric conversion units includes a first photoelectric conversion unit that receives a light beam that passes through a first pupil region of an exit pupil of the optical system, and a second photoelectric conversion unit that receives a light beam that passes through a second pupil region of the exit pupil of the optical system, and a light receiving area of ​​the first photoelectric conversion unit of the first pixel is different from a light receiving area of ​​the first photoelectric conversion unit of the second pixel.

19. The focus detection device according to claim 18, wherein the first pixel has a first light-shielding portion that blocks a portion of the light beam from the optical system, and the second pixel has a second light-shielding portion that blocks a portion of the light beam from the optical system and has an area different from that of the first light-shielding portion.

20. A focus detection device as described in any one of claims 11 to 19, wherein the first pixel includes a first pixel pair that receives light beams that pass through different pupil regions of an exit pupil of the optical system, and the second pixel includes a second pixel pair that receives light beams that pass through different pupil regions of an exit pupil of the optical system.

21. The focus detection device according to any one of claims 11 to 20, wherein the instruction to perform focus detection of the optical system is a half-press operation by a user.

22. The focus detection device described in any one of claims 11 to 21, wherein the control unit performs a scanning operation to move a focus lens of the optical system after the first period has elapsed since receiving an instruction to perform focus detection of the optical system, if the detection unit is unable to perform focus detection of the optical system based on the signal of the one pixel but is able to perform focus detection of the optical system based on the signal of the other pixel, and performs the scanning operation after a second period shorter than the first period has elapsed since receiving an instruction to perform focus detection of the optical system, if the detection unit is unable to perform focus detection of the optical system based on either the signal of the first pixel or the signal of the second pixel.

23. An imaging device comprising: a focus detection device according to any one of claims 11 to 22; and a detachable section to which an interchangeable lens having the optical system can be detached.

Images