JP2013054326A - Focus detector and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focus detector capable of properly detecting a focus of an optical system.SOLUTION: The focus detector comprises: a phase difference detection section for acquiring an image deviation signal corresponding to deviation amount of image surfaces by optical systems 31, 32 and 33, selecting a filter capable of detecting a frequency band suitable for the image deviation signal of a plurality of filters and detecting the deviation amount on the basis of a filter processing signal obtained by performing filter processing on the image deviation signal; a contrast detection section for detecting the focus states of the optical systems 31, 32 and 33 from the contrast of the images by the optical systems 31, 32 and 33; and a control section for determining whether or not the frequency band detectable by the selected filter is a frequency band different from a specific frequency band corresponding to a photographic scene and executing scan driving of the phase difference detection section and the contrast detection section, while driving the focus adjustment optical system 32 in a prescribed direction, when the frequency band of the selected filter is the frequency band different from the specific frequency band.

Description

  The present invention relates to a focus detection apparatus and an imaging apparatus.

  Conventionally, when adjusting the focus of an optical system, in order to improve the focus adjustment accuracy, first, the focus state of the optical system is detected by the phase difference detection method, and the focus is determined based on the detection result by the phase difference detection method. The adjustment lens is driven to the vicinity of the focus position, and then the focus state of the optical system is detected by the contrast detection method in the vicinity of the focus position, and the focus adjustment lens is focused based on the detection result by the contrast detection method. A technique for driving to a position is known (for example, see Patent Document 1).

JP 2006-84545 A

  However, in the prior art, focus detection is first performed by the phase difference detection method, and subsequently focus detection is performed by the contrast detection method. Therefore, there is a problem that it takes time to detect the focus.

  The problem to be solved by the present invention is to provide a focus detection apparatus capable of appropriately performing focus detection of an optical system.

  The present invention solves the above problems by the following means. In the following description, the reference numerals corresponding to the drawings showing the embodiments of the present invention are used for explanation, but these reference numerals are only for facilitating the understanding of the present invention and are not intended to limit the invention. Absent.

  [1] A focus detection apparatus according to a first aspect of the present invention captures an image by an optical system (31, 32, 33) having a focus adjustment optical system, and outputs an image signal corresponding to the captured image. A phase difference detection unit (222a, 222b) for detecting a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference (22), and the imaging unit; The contrast detection unit (221) for detecting the focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the optical system, and the phase difference detection unit A storage unit (21) for storing a plurality of filters having different frequency bands that can be detected and used for detection of a focus state, a scene determination unit (21) for determining a shooting scene, and an optical axis direction of the optical system, The focus A drive unit (36) for driving the moderating optical system (32); and a control unit (21) for controlling the drive of the focus adjustment optical system by controlling the drive unit, and the phase difference detection unit Acquires an image shift signal corresponding to an image plane shift amount by the optical system using a phase difference, and filters the acquired image shift signal using the plurality of filters stored in the storage unit. After processing and calculating a plurality of filter processing signals processed by the plurality of filters, out of a plurality of filters used for calculation of the plurality of filter processing signals, a frequency band suitable for the acquired image shift signal is selected. A detectable filter is selected, the amount of deviation is detected based on a filter processing signal obtained using the selected filter among the plurality of filter processing signals, and the control unit is configured to detect the phase difference. Detection unit As a result of detecting the focus state of the optical system, the frequency band that can be detected by the filter selected by the phase difference detection unit is a specific frequency band corresponding to the shooting scene determined by the scene determination unit. It is determined whether or not the frequency band is different, and when the frequency band of the selected filter is a frequency band different from the specific frequency band, the focus adjustment optical system is provided in the drive unit with a predetermined frequency band. While driving in the direction, scan driving is performed to cause the phase difference detection unit and the contrast detection unit to detect the focus state of the optical system.

  [2] A focus detection apparatus according to the second aspect of the present invention captures an image by an optical system (31, 32, 33) having a focus adjustment optical system, and outputs an image signal corresponding to the captured image. A phase difference detection unit (222a, 222b) for detecting a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference (22), and the imaging unit; The contrast detection unit (221) for detecting the focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the optical system, and the phase difference detection unit A storage unit (21) for storing a plurality of filters having different frequency bands that can be detected and used for detection of a focus state, a scene determination unit (21) for determining a shooting scene, and an optical axis direction of the optical system, The focus A drive unit (36) for driving the moderating optical system (32); and a control unit (21) for controlling the drive of the focus adjustment optical system by controlling the drive unit, and the phase difference detection unit Acquires an image shift signal corresponding to an image plane shift amount by the optical system using a phase difference, and selects a filter capable of detecting a frequency band suitable for the image shift signal from the plurality of filters. The shift amount is detected based on a filter processing signal obtained by filtering the acquired image shift signal with the selected filter, and the control unit supplies the optical signal to the phase difference detection unit. As a result of detecting the focus state of the system, the frequency band that can be detected by the filter selected by the phase difference detection unit differs from the specific frequency band corresponding to the shooting scene determined by the scene determination unit. Whether the frequency band of the selected filter is a frequency band different from the specific frequency band is determined whether or not it is a wave number band. While being driven, the phase difference detection unit and the contrast detection unit perform scan driving for detecting the focus state of the optical system.

  [3] A focus detection apparatus according to a third aspect of the present invention captures an image by an optical system (31, 32, 33) having a focus adjustment optical system, and outputs an image signal corresponding to the captured image. A phase difference detection unit (222a, 222b) that detects a focal state of the optical system by detecting a shift amount of the image plane by the optical system using the unit (22), and the phase difference; and the phase difference A storage unit (21) for storing a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the detection unit, a scene determination unit (21) for determining a shooting scene, and an optical axis of the optical system A drive unit (36) for driving the focus adjustment optical system (32) in a direction, and a control unit (21) for controlling the drive of the focus adjustment optical system by controlling the drive unit; The phase difference detection unit uses the phase difference, and An image shift signal corresponding to an image plane shift amount by an academic system is acquired, and the acquired image shift signal is filtered using the plurality of filters stored in the storage unit, and processed by the plurality of filters. After calculating the plurality of filtered signals, a filter capable of detecting a frequency band suitable for the acquired image shift signal is selected from the plurality of filters used for calculating the plurality of filtered signals, The shift amount is detected based on a filter processing signal obtained by using the selected filter among a plurality of filter processing signals, and the control unit detects a focus state of the optical system in the phase difference detection unit. As a result of the detection, the frequency band that can be detected by the filter selected by the phase difference detection unit is a specific frequency band corresponding to the shooting scene determined by the scene determination unit If the frequency band of the selected filter is a frequency band different from the specific frequency band, the deviation amount detected by the phase difference detection unit is determined. The control based on is prohibited.

  [4] A focus detection apparatus according to a fourth aspect of the present invention captures an image by an optical system (31, 32, 33) having a focus adjustment optical system, and outputs an image signal corresponding to the captured image. A phase difference detection unit (222a, 222b) that detects a focal state of the optical system by detecting a shift amount of the image plane by the optical system using the unit (22), and the phase difference; and the phase difference A storage unit (21) for storing a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the detection unit, a scene determination unit (21) for determining a shooting scene, and an optical axis of the optical system A drive unit (36) for driving the focus adjustment optical system (32) in a direction, and a control unit (21) for controlling the drive of the focus adjustment optical system by controlling the drive unit; The phase difference detection unit uses the phase difference, and An image shift signal corresponding to an image plane shift amount by an academic system is acquired, a filter capable of detecting a frequency band suitable for the image shift signal is selected from the plurality of filters, and the filter is used to select the filter. The control unit detects the shift amount based on the filter processing signal obtained by filtering the acquired image shift signal, and the control unit causes the phase difference detection unit to detect the focus state of the optical system. As a result, it is determined whether or not the frequency band detectable by the filter selected by the phase difference detection unit is a frequency band different from the specific frequency band corresponding to the shooting scene determined by the scene determination unit. When the frequency band of the selected filter is a frequency band different from the specific frequency band, it is based on the deviation amount detected by the phase difference detection unit. A focus detection device that prohibits control.

  [5] In the focus detection apparatus according to the first to fourth aspects of the present invention, the frequency band of the filter selected by the control unit (21) by the phase difference detection units (222a, 222b) is the specified When in the frequency band, the drive unit (36) is configured to drive the focus adjustment optical system (32) based on the shift amount detected by the phase difference detection unit. Can do.

  [6] In the focus detection apparatus according to the first to fourth aspects of the present invention, the scene determination unit (21) is imaged by a scene set by a user via an operation member or by the imaging unit It can be configured to determine the shooting scene based on the captured image.

  [7] In the focus detection apparatus according to the first to fourth aspects of the present invention, the control unit (21) determines that the shooting scene is a scene in which a human face is shot by the scene determination unit (21). In such a case, the specific frequency band can be set to a frequency band equal to or higher than a predetermined first threshold.

  [8] In the focus detection apparatus according to the first to fourth aspects of the present invention, when the control unit (21) captures a human face by the scene determination unit (21). If it is determined, the specific frequency band is set to a frequency band equal to or higher than a predetermined first threshold, and the scene determination unit determines that the shooting scene is a macro shooting scene or a scene shooting scene. In this case, the specific frequency band can be set to a frequency band equal to or higher than a predetermined second threshold value that is higher than the first threshold value.

  [9] In the focus detection apparatus according to the first to fourth aspects of the present invention, the phase difference detection unit (222a, 222b) is configured to shift the shift with respect to each of a plurality of focus detection positions set in a shooting screen. The amount is detected, and the control unit (21) uses a filter capable of detecting a frequency band different from the specific frequency band among the plurality of deviation amounts detected for each of the plurality of detection positions. The phase difference detection unit can be configured to detect the focus state of the optical system by excluding the shifted amount.

  [10] A focus detection apparatus according to a fifth aspect of the present invention captures an image by an optical system (31, 32, 33) having a focus adjustment optical system and outputs an image signal corresponding to the captured image. A phase difference detection unit (222a, 222b) for detecting a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference (22), and the imaging unit; The contrast detection unit (221) for detecting the focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the optical system, and the phase difference detection unit A storage unit (21) used for detecting a focus state and storing a plurality of filters having different detectable frequency bands, and a drive unit for driving the focus adjustment optical system (32) in the optical axis direction of the optical system (32 ) And a control unit (21) for controlling the driving of the focus adjusting optical system by controlling the driving unit, and the phase difference detecting unit uses the phase difference to generate an image by the optical system. An image shift signal corresponding to a surface shift amount is acquired, the acquired image shift signals are filtered using the plurality of filters stored in the storage unit, and a plurality of filters processed by the plurality of filters are processed. After calculating the filter processing signal, a filter capable of detecting a frequency band suitable for the acquired image shift signal is selected from the plurality of filters used for calculating the plurality of filter processing signals, and the plurality of filter processing Based on the filter processing signal obtained using the selected filter among the signals, the shift amount is detected, and the control unit detects the focus state of the optical system in the phase difference detection unit. Let it come As a result, the amount of deviation detected by the phase difference detection unit is equal to or greater than a predetermined value, and the frequency band that can be detected by the filter selected by the phase difference detection unit is higher than a predetermined specific frequency band. A determination is made as to whether or not the band is a band, and the amount of deviation is equal to or greater than the predetermined value, and the frequency band that can be detected by the selected filter is a frequency band higher than the specific frequency band. Performing a scan drive that causes the phase difference detection unit and the contrast detection unit to detect the focus state of the optical system while causing the drive unit to drive the focus adjustment optical system in a predetermined direction. Features.

  [11] A focus detection apparatus according to a sixth aspect of the present invention captures an image by an optical system (31, 32, 33) having a focus adjustment optical system, and outputs an image signal corresponding to the captured image. A phase difference detection unit (222a, 222b) for detecting a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference (22), and the imaging unit; The contrast detection unit (221) for detecting the focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the optical system, and the phase difference detection unit A storage unit (21) used for detecting a focus state and storing a plurality of filters having different detectable frequency bands, and a drive unit for driving the focus adjustment optical system (32) in the optical axis direction of the optical system (32 ) And a control unit (21) for controlling the driving of the focus adjusting optical system by controlling the driving unit, and the phase difference detecting unit uses the phase difference to generate an image by the optical system. An image shift signal corresponding to a surface shift amount is acquired, a filter capable of detecting a frequency band suitable for the image shift signal is selected from a plurality of filters having different detectable frequency bands, and the selected filter The control unit detects the shift amount based on the filter processing signal obtained by filtering the acquired image shift signal, and the control unit detects the focus state of the optical system in the phase difference detection unit. As a result, the amount of deviation detected by the phase difference detection unit is greater than or equal to a predetermined value, and the detectable frequency band of the filter selected by the phase difference detection unit is greater than a predetermined specific frequency band. Also It is determined whether or not the frequency band is a high frequency band, the deviation amount is equal to or greater than the predetermined value, and the frequency band detectable by the selected filter is a frequency band higher than the specific frequency band. In this case, scan driving is performed so that the phase difference detection unit and the contrast detection unit detect the focus state of the optical system while driving the focus adjustment optical system in a predetermined direction. It is characterized by that.

  [12] In the focus detection apparatus according to the sixth aspect of the present invention, the control unit (21) may be configured to set the predetermined value according to an aperture value of the optical system.

  [13] In the focus detection apparatus according to the first to sixth aspects of the present invention, the phase difference detection unit (222a, 222b) is configured to be provided on the light receiving surface of the imaging unit (22). be able to.

  [14] An imaging apparatus according to the present invention includes the focus detection apparatus.

  According to the present invention, focus detection of an optical system can be performed appropriately.

FIG. 1 is a block diagram showing a camera according to the present embodiment. FIG. 2 is a front view showing an imaging surface of the imaging device shown in FIG. FIG. 3 is a front view schematically showing the arrangement of the focus detection pixels 222a and 222b by enlarging the vicinity of the focus detection pixel row 22a of FIG. FIG. 4 is an enlarged front view showing one of the imaging pixels 221. FIG. 5A is an enlarged front view showing one of the focus detection pixels 222a, and FIG. 5B is an enlarged front view showing one of the focus detection pixels 222b. FIG. 6 is an enlarged cross-sectional view showing one of the imaging pixels 221. FIG. 7A is an enlarged cross-sectional view showing one of the focus detection pixels 222a, and FIG. 7B is an enlarged cross-sectional view showing one of the focus detection pixels 222b. FIG. 8 is a diagram for explaining the sizes of the focus detection pixels 222a and 222b. FIG. 9 is a diagram for explaining the size of each pixel constituting the line sensor provided in the conventional phase difference detection module. 10 is a cross-sectional view taken along line XX of FIG. FIG. 11 is a flowchart showing the operation of the camera according to the present embodiment. FIG. 12 is a diagram illustrating the relationship between the focus lens position and the focus evaluation value and the relationship between the focus lens position and time in the search operation according to the present embodiment.

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

  FIG. 1 is a main part configuration diagram showing a digital camera 1 according to an embodiment of the present invention. A digital camera 1 according to the present embodiment (hereinafter simply referred to as a camera 1) includes a camera body 2 and a lens barrel 3, and the camera body 2 and the lens barrel 3 are detachably coupled by a mount unit 4. Yes.

  The lens barrel 3 is an interchangeable lens that can be attached to and detached from the camera body 2. As shown in FIG. 1, the lens barrel 3 includes a photographic optical system including lenses 31, 32, 33 and a diaphragm 34.

  The lens 32 is a focus lens, and can adjust the focal length of the photographing optical system by moving in the direction of the optical axis L1. The focus lens 32 is provided so as to be movable along the optical axis L1 of the lens barrel 3, and its position is adjusted by the focus lens drive motor 36 while its position is detected by the encoder 35.

  The specific configuration of the moving mechanism along the optical axis L1 of the focus lens 32 is not particularly limited. For example, a rotating cylinder is rotatably inserted into a fixed cylinder fixed to the lens barrel 3, a helicoid groove (spiral groove) is formed on the inner peripheral surface of the rotating cylinder, and the focus lens 32 is fixed. The end of the lens frame is fitted into the helicoid groove. Then, by rotating the rotating cylinder by the focus lens drive motor 36, the focus lens 32 fixed to the lens frame moves straight along the optical axis L1.

  As described above, the focus lens 32 fixed to the lens frame by rotating the rotary cylinder with respect to the lens barrel 3 moves straight in the direction of the optical axis L1, but the focus lens drive motor 36 as the drive source is the lens. The lens barrel 3 is provided. The focus lens drive motor 36 and the rotary cylinder are connected by a transmission composed of a plurality of gears, for example, and when the drive shaft of the focus lens drive motor 36 is driven to rotate in any one direction, it is transmitted to the rotary cylinder at a predetermined gear ratio. Then, when the rotating cylinder rotates in any one direction, the focus lens 32 fixed to the lens frame moves linearly in any direction of the optical axis L1. When the drive shaft of the focus lens drive motor 36 is rotated in the reverse direction, the plurality of gears constituting the transmission also rotate in the reverse direction, and the focus lens 32 moves straight in the reverse direction of the optical axis L1. .

  The position of the focus lens 32 is detected by the encoder 35. As described above, the position of the focus lens 32 in the optical axis L1 direction correlates with the rotation angle of the rotating cylinder, and can be obtained by detecting the relative rotation angle of the rotating cylinder with respect to the lens barrel 3, for example.

  As the encoder 35 of this embodiment, an encoder that detects the rotation of a rotating disk coupled to the rotational drive of the rotating cylinder with an optical sensor such as a photo interrupter and outputs a pulse signal corresponding to the number of rotations, or a fixed cylinder And the contact point of the brush on the surface of the flexible printed wiring board provided on either one of the rotating cylinders, and the brush contact provided on the other, the amount of movement of the rotating cylinder (in either the rotational direction or the optical axis direction) A device that detects a change in the contact position according to the detection circuit using a detection circuit can be used.

  The focus lens 32 can move in the direction of the optical axis L1 from the end on the camera body side (also referred to as the closest end) to the end on the subject side (also referred to as the infinite end) by the rotation of the rotating cylinder described above. it can. Incidentally, the current position information of the focus lens 32 detected by the encoder 35 is sent to the camera control unit 21 to be described later via the lens control unit 37, and the focus lens drive motor 36 calculates the focus calculated based on this information. The driving position of the lens 32 is driven by being sent from the camera control unit 21 via the lens control unit 37.

  The diaphragm 34 is configured such that the aperture diameter around the optical axis L1 can be adjusted in order to limit the amount of light flux that passes through the photographing optical system and reaches the image sensor 22 and to adjust the blur amount. The adjustment of the aperture diameter by the diaphragm 34 is performed, for example, by sending an appropriate aperture diameter calculated in the automatic exposure mode from the camera control unit 21 via the lens control unit 37. Further, the set aperture diameter is input from the camera control unit 21 to the lens control unit 37 by a manual operation by the operation unit 28 provided in the camera body 2. The aperture diameter of the aperture 34 is detected by an aperture sensor (not shown), and the lens controller 37 recognizes the current aperture diameter.

  The lens control unit 37 is electrically connected to the camera control unit 21 by an electric signal contact unit 41 provided on the mount unit 4, and is driven by the focus lens 32 and opened by the diaphragm 34 based on a command from the camera control unit 21. In addition to adjusting the aperture, lens information such as the position of the focus lens 32 and the aperture diameter of the diaphragm 34 is transmitted to the camera control unit 21.

  On the other hand, the camera body 2 is provided with an imaging element 22 that receives the light beam L1 from the photographing optical system on a planned focal plane of the photographing optical system, and a shutter 23 is provided on the front surface thereof. The image sensor 22 is composed of a device such as a CCD or CMOS, converts the received optical signal into an electrical signal, and sends it to the camera control unit 21. The captured image information sent to the camera control unit 21 is sequentially sent to the liquid crystal drive circuit 25 and displayed on the electronic viewfinder (EVF) 26 of the observation optical system, and a release button ( When (not shown) is fully pressed, the photographed image information is recorded in the camera memory 24 which is a recording medium. The camera memory 24 can be either a removable card type memory or a built-in memory. Details of the structure of the image sensor 22 will be described later.

  The camera body 2 is provided with an observation optical system for observing an image picked up by the image pickup device 22. The observation optical system of the present embodiment includes an electronic viewfinder (EVF) 26 composed of a liquid crystal display element, a liquid crystal driving circuit 25 that drives the electronic viewfinder (EVF) 26, and an eyepiece lens 27. The liquid crystal drive circuit 25 reads the captured image information captured by the image sensor 22 and sent to the camera control unit 21, and drives the electronic viewfinder 26 based on the read image information. Thereby, the user can observe the current captured image through the eyepiece lens 27. Note that, instead of or in addition to the observation optical system using the optical axis L2, a liquid crystal display may be provided on the back surface of the camera body 2, and a photographed image may be displayed on the liquid crystal display.

  A camera control unit 21 is provided in the camera body 2. The camera control unit 21 is electrically connected to the lens control unit 37 through an electric signal contact unit 41 provided in the mount unit 4, receives lens information from the lens control unit 37, and defocuses to the lens control unit 37. Send information such as volume and aperture diameter. The camera control unit 21 reads out the pixel output from the image sensor 22 as described above, generates image information by performing predetermined information processing on the read out pixel output as necessary, and generates the generated image information. Are output to the liquid crystal drive circuit 25 and the camera memory 24 of the electronic viewfinder 26. The camera control unit 21 controls the entire camera 1 such as correction of image information from the image sensor 22 and detection of a focus adjustment state and an aperture adjustment state of the lens barrel 3.

  In addition to the above, the camera control unit 21 detects the focus state of the photographic optical system by the phase detection method and the focus state of the photographic optical system by the contrast detection method based on the pixel data read from the image sensor 22. I do. A specific focus state detection method will be described later.

  The operation unit 28 is an input switch for a photographer to set various operation modes of the camera 1 such as a shutter release button and a moving image shooting start switch. The operation unit 28 switches between an auto focus mode / manual focus mode and an auto focus mode. In particular, the one-shot mode / continuous mode can be switched. In addition to this, the operation unit 28 can also select a shooting mode. Specifically, a person shooting mode for shooting a person's face, a macro shooting mode for macro shooting, Alternatively, it is possible to select a landscape shooting mode for shooting a landscape. Various modes set by the operation unit 28 are sent to the camera control unit 21, and the operation of the entire camera 1 is controlled by the camera control unit 21. The shutter release button includes a first switch SW1 that is turned on when the button is half-pressed and a second switch SW2 that is turned on when the button is fully pressed.

  Next, the image sensor 22 according to the present embodiment will be described.

  FIG. 2 is a front view showing the imaging surface of the imaging element 22, and FIG. 3 is a front view schematically showing the arrangement of the focus detection pixels 222a and 222b by enlarging the vicinity of the focus detection pixel row 22a in FIG.

  As shown in FIG. 3, the imaging element 22 of the present embodiment includes a green pixel G having a color filter in which a plurality of imaging pixels 221 are two-dimensionally arranged on the plane of the imaging surface and transmit a green wavelength region. A red pixel R having a color filter that transmits a red wavelength region and a blue pixel B having a color filter that transmits a blue wavelength region are arranged in a so-called Bayer Arrangement. That is, in four adjacent pixel groups 223 (dense square lattice arrangement), two green pixels are arranged on one diagonal line, and one red pixel and one blue pixel are arranged on the other diagonal line. The image sensor 22 is configured by repeatedly arranging the pixel group 223 on the imaging surface of the image sensor 22 in a two-dimensional manner with the Bayer array pixel group 223 as a unit.

  The unit pixel group 223 may be arranged in a dense hexagonal lattice arrangement other than the dense square lattice shown in the figure. Further, the configuration and arrangement of the color filters are not limited to this, and an arrangement of complementary color filters (green: G, yellow: Ye, magenta: Mg, cyan: Cy) can also be adopted.

  FIG. 4 is an enlarged front view showing one of the imaging pixels 221, and FIG. 6 is a cross-sectional view. One imaging pixel 221 includes a micro lens 2211, a photoelectric conversion unit 2212, and a color filter (not shown), and a photoelectric conversion unit is formed on the surface of the semiconductor circuit substrate 2213 of the image sensor 22 as shown in the cross-sectional view of FIG. 2212 is built in and a microlens 2211 is formed on the surface. The photoelectric conversion unit 2212 is configured to receive an imaging light beam that passes through an exit pupil (for example, F1.0) of the photographing optical system by the micro lens 2211, and receives the imaging light beam.

  Further, on the imaging surface of the imaging element 22, five focus detection pixel rows 22a to 22e in which focus detection pixels 222a and 222b are arranged instead of the above-described imaging pixel 221 are provided. As shown in FIG. 3, one focus detection pixel column is configured by a plurality of focus detection pixels 222 a and 222 b being alternately arranged adjacent to each other in a horizontal row. In the present embodiment, the focus detection pixels 222a and 222b are densely arranged without providing a gap at the position of the green pixel G and the blue pixel B of the image pickup pixel 221 arranged in the Bayer array.

  Note that the positions of the focus detection pixel rows 22a to 22e shown in FIG. 2 are not limited to the illustrated positions, and may be any one, two, three, or four locations, and more than six locations. It can also be arranged at the position. FIG. 3 shows an example in which the focus detection pixel array is configured by 16 focus detection pixels 222a and 222b, but the number of focus detection pixels configuring the focus detection pixel array is limited to this example. Is not to be done.

  FIG. 5A is an enlarged front view showing one of the focus detection pixels 222a, and FIG. 7A is a cross-sectional view of the focus detection pixel 222a. FIG. 5B is an enlarged front view showing one of the focus detection pixels 222b, and FIG. 7B is a cross-sectional view of the focus detection pixel 222b. As shown in FIG. 5A, the focus detection pixel 222a includes a micro lens 2221a and a semicircular photoelectric conversion unit 2222a. As shown in the cross-sectional view of FIG. A photoelectric conversion portion 2222a is formed on the surface of the semiconductor circuit substrate 2213, and a micro lens 2221a is formed on the surface. The focus detection pixel 222b includes a micro lens 2221b and a photoelectric conversion unit 2222b as shown in FIG. 5B, and a semiconductor of the image sensor 22 as shown in a cross-sectional view of FIG. 7B. A photoelectric conversion unit 2222b is formed on the surface of the circuit board 2213, and a microlens 2221b is formed on the surface. Then, as shown in FIG. 3, these focus detection pixels 222a and 222b are alternately arranged adjacent to each other in a horizontal row, thereby forming focus detection pixel rows 22a to 22c shown in FIG.

  Here, as shown in FIG. 8, the focus detection pixels 222a and 222b are required to have substantially the same size as the imaging pixel 221 because of the structure thereof. Both the width L1 and the lateral width L2 are normally set to a size of about 10 μm or less. On the other hand, in the conventional line sensor (phase difference detection sensor) provided in the phase difference detection module, as shown in FIG. 9, there is no particular limitation on the size thereof, so the size of each pixel 50a of the line sensor 50 is large. In general, the vertical width L3 is set to about several hundred μm, and the horizontal width L4 is set to about several tens μm to several hundred μm. That is, the size of each pixel 50a of the conventional line sensor 50 is several hundreds μm × several tens μm to several hundreds μm, whereas the focus detection pixels 222a and 222b are set to a size of 10 μm square or less. Yes. FIG. 8 is a diagram for explaining the pixel sizes of the focus detection pixels 222a and 222b, and FIG. 9 shows the size of each pixel constituting the line sensor provided in the conventional phase difference detection module. It is a figure for demonstrating this.

  The photoelectric conversion units 2222a and 2222b of the focus detection pixels 222a and 222b have such a shape that the microlenses 2221a and 2221b receive a light beam that passes through a predetermined region (eg, F2.8) of the exit pupil of the photographing optical system. Is done. Further, the focus detection pixels 222a and 222b are not provided with color filters, and their spectral characteristics are the total of the spectral characteristics of a photodiode that performs photoelectric conversion and the spectral characteristics of an infrared cut filter (not shown). ing. However, it may be configured to include one of the same color filters as the imaging pixel 221, for example, a green filter.

  In addition, although the photoelectric conversion units 2222a and 2222b of the focus detection pixels 222a and 222b illustrated in FIGS. 5A and 5B have a semicircular shape, the shapes of the photoelectric conversion units 2222a and 2222b are not limited thereto. Other shapes such as an elliptical shape, a rectangular shape, and a polygonal shape can also be used.

  Here, a so-called phase difference detection method for detecting the focus state of the photographing optical system based on the pixel outputs of the focus detection pixels 222a and 222b described above will be described.

  FIG. 10 is a cross-sectional view taken along the line XX in FIG. 3. The focus detection pixels 222 a-1, 222 b-1, 222 a-2, and 222 b-2 arranged in the vicinity of the photographing optical axis L 1 are adjacent to each other. It shows that light beams AB1-1, AB2-1, AB1-2, and AB2-2 irradiated from the distance measuring pupils 351 and 352 of the exit pupil 350 are received. 10 illustrates only the focus detection pixels 222a and 222b that are located in the vicinity of the photographing optical axis L1, but other focus detection pixels other than the focus detection pixels illustrated in FIG. 10 are illustrated. In the same manner, the light beams emitted from the pair of distance measuring pupils 351 and 352 are respectively received.

  Here, the exit pupil 350 is an image set at a distance D in front of the microlenses 2221a and 2221b of the focus detection pixels 222a and 222b arranged on the planned focal plane of the photographing optical system. The distance D is a value uniquely determined according to the curvature and refractive index of the microlens, the distance between the microlens and the photoelectric conversion unit, and the distance D is referred to as a distance measurement pupil distance. The distance measurement pupils 351 and 352 are images of the photoelectric conversion units 2222a and 2222b respectively projected by the micro lenses 2221a and 2221b of the focus detection pixels 222a and 222b.

  In FIG. 10, the arrangement direction of the focus detection pixels 222a-1, 222b-1, 222a-2, and 222b-2 coincides with the arrangement direction of the pair of distance measurement pupils 351 and 352.

  Further, as shown in FIG. 10, the microlenses 2221a-1, 2221b-1, 2221a-2, and 2221b-2 of the focus detection pixels 222a-1, 222b-1, 222a-2, and 222b-2 are photographic optical systems. Near the planned focal plane. The shapes of the photoelectric conversion units 2222a-1, 2222b-1, 2222a-2, 2222b-2 arranged behind the micro lenses 2221a-1, 2221b-1, 2221a-2, 2221b-2 are the same as the micro lenses 2221a-1, 2221b-1, 2221a-2, 2221b-2. Projected onto the exit pupil 350 that is separated from the lenses 2221 a-1, 2221 b-1, 2221 a-2, and 2221 b-2 by a distance measurement distance D, and the projection shape forms distance measurement pupils 351 and 352.

  That is, the microlens and the photoelectric conversion unit in each focus detection pixel so that the projection shapes (distance measurement pupils 351 and 352) of the focus detection pixels coincide on the exit pupil 350 at the distance D. Is determined, and the projection direction of the photoelectric conversion unit in each focus detection pixel is thereby determined.

  As shown in FIG. 10, the photoelectric conversion unit 2222a-1 of the focus detection pixel 222a-1 is formed on the microlens 2221a-1 by a light beam AB1-1 that passes through the distance measuring pupil 351 and goes to the microlens 2221a-1. A signal corresponding to the intensity of the image to be output is output. Similarly, the photoelectric conversion unit 2222a-2 of the focus detection pixel 222a-2 passes through the distance measuring pupil 351, and the intensity of the image formed on the microlens 2221a-2 by the light beam AB1-2 toward the microlens 2221a-2. The signal corresponding to is output.

  Further, the photoelectric conversion unit 2222b-1 of the focus detection pixel 222b-1 passes through the distance measuring pupil 352, and the intensity of the image formed on the microlens 2221b-1 by the light beam AB2-1 directed to the microlens 2221b-1. Output the corresponding signal. Similarly, the photoelectric conversion unit 2222b-2 of the focus detection pixel 222b-2 passes through the distance measuring pupil 352, and the intensity of the image formed on the microlens 2221b-2 by the light beam AB2-2 toward the microlens 2221b-2. The signal corresponding to is output.

  Then, a plurality of the above-described two types of focus detection pixels 222a and 222b are arranged in a straight line as shown in FIG. 3, and the outputs of the photoelectric conversion units 2222a and 2222b of the focus detection pixels 222a and 222b are used as the distance measurement pupil 351. Of the pair of images formed on the focus detection pixel array by the focus detection light fluxes passing through each of the distance measurement pupil 351 and the distance measurement pupil 352. Data on the distribution is obtained. Next, filter processing is performed on the intensity distribution data of the pair of images using a plurality of detection filters having different detection frequency bands, and post-filter processing data is calculated for each detection filter.

  Here, in the present embodiment, a plurality of detection filters having different detection frequency bands (that is, detectable frequency bands) are controlled by the camera so as to correspond to the spatial frequency of the subject corresponding to the intensity distribution data of the pair of images. Stored in the unit 21. That is, the camera control unit 21 stores a plurality of detection filters having different detection frequency bands so as to be compatible with the spatial frequency of any subject from a low frequency subject to a high frequency subject.

  In this embodiment, the intensity distribution data of the pair of images obtained as described above is subjected to filter processing using a plurality of detection filters having different detection frequency bands, and data after filter processing is performed for each detection filter. Is calculated. That is, when the number of detection filters stored in the camera control unit 21 is 10, 10 pieces of filtered data are calculated. Then, an image shift detection calculation process (correlation calculation process) is performed on the obtained post-filter data (for example, ten post-filter data) for each detection filter, so that a so-called phase difference detection method is used. A plurality of focus amounts are calculated for each data after filtering.

Specifically, the camera control unit 21 reads the first image data strings a ₁ , a ₂ ,... After filtering, which are read out from each focus detection pixel 222a and then obtained by filtering. . . , _An, and the filtered second image data sequence b ₁ , b ₂ ,. . . and b _n, while relatively shifting one-dimensionally, performs correlation calculation of the following formula (1).
C (k) = Σ | a (n + k) −b (n) | (1)
In the above equation (1), the Σ operation indicates a cumulative operation (phase sum operation) for n, and is limited to a range in which data of a (n + k) and b (n) exist according to the image shift amount k. The The image shift amount k is an integer, and is a shift amount in units of pixel intervals between the focus detection pixels 222a and 222b. In the calculation result of the above formula (1), the correlation amount C (k) is minimal (the correlation degree is higher as it is smaller) in the shift amount where the correlation between the pair of image data is high.

Next, the camera control unit 21 calculates a minimum value of the correlation amount based on the calculated correlation amount C (k). In the present embodiment, for example, the minimum value C (x) and the minimum value C (x) with respect to the continuous correlation amount are obtained by using the three-point interpolation method shown in the following formulas (2) to (5). The shift amount x that gives is calculated as an image shift amount. Note that C (kj) shown in the following equation is C (k−1) ≧ C (k) and C (k + 1)> C (k) among the correlation amounts C (k) obtained in the above equation (1). ) Satisfying the condition of
D = {C (kj−1) −C (kj + 1)} / 2 (2)
C (x) = C (kj) − | D | (3)
x = kj + D / SLOP (4)
SLOP = MAX {C (kj + 1) -C (kj), C (kj-1) -C (kj)} (5)

Then, the camera control unit 21 calculates the defocus amount df according to the following equation (6) based on the shift amount x from which the minimum value C (x) of the correlation amount is obtained. In the above equation (6), k is a conversion coefficient (k factor) for converting the shift amount x from which the minimum value C (x) of the correlation amount is obtained into the defocus amount. In the present embodiment, such correlation calculation processing is performed on all of the plurality of post-filter data.
df = x · k (6)

  Then, the camera control unit 21 selects a detection filter having a detection frequency band suitable for the corresponding subject from the plurality of detection filters based on the calculation result in the correlation calculation process, and the camera control unit 21 is obtained using the selected detection filter. The determined defocus amount is determined as the final defocus amount. That is, by selecting a detection filter having a detection frequency band suitable for the corresponding subject, the final defocus amount is determined from the plurality of defocus amounts calculated as described above.

  Here, as a method of selecting a detection filter having a detection frequency band suitable for the corresponding subject from a plurality of detection filters, for example, as the minimum value C (x) of the correlation amount calculated in the correlation calculation processing, It is determined that a small value is obtained using a detection filter having a detection frequency band suitable for the corresponding subject, and a detection filter is selected based on the determination. It is done. In the present embodiment, the detection frequency band suitable for the corresponding subject is normally a detection frequency band including the spatial frequency of the subject. Therefore, the lower the spatial frequency of the corresponding subject, the more suitable for the subject. The detection frequency band of the detection filter having the detection frequency band is lower, while the detection frequency band of the detection filter having the detection frequency band suitable for the subject is higher as the spatial frequency of the corresponding subject is higher.

  The calculation of the image shift amount by the phase difference detection method and the calculation of the defocus amount based thereon are executed by the camera control unit 21.

  Further, the camera control unit 21 reads the output of the imaging pixel 221 of the imaging element 22 and calculates a focus evaluation value based on the read pixel output. This focus evaluation value can be obtained by, for example, extracting a high frequency component of an image output from the imaging pixel 221 of the imaging element 22 using a high frequency transmission filter and integrating the extracted high frequency component. It can also be obtained by extracting high-frequency components using two high-frequency transmission filters having different cutoff frequencies and integrating them.

  Then, the camera control unit 21 sends a control signal to the lens control unit 37 to drive the focus lens 32 at a predetermined sampling interval (distance) to obtain a focus evaluation value at each position, and the focus evaluation value is maximum. The focus detection by the contrast detection method is performed in which the position of the focus lens 32 is determined as the in-focus position. Note that this in-focus position is obtained when, for example, when the focus evaluation value is calculated while driving the focus lens 32, the focus evaluation value rises twice and then moves down twice. Can be obtained by performing an operation such as interpolation using the focus evaluation value.

  Next, an example of the operation of the camera 1 in the present embodiment will be described along the flowchart shown in FIG. In the following, for example, an operation example in the case where a person photographing mode for photographing a person's face is selected via the operation unit 28 will be described. The following operation is started when the camera 1 is turned on.

  First, in step S1, generation of a through image by the camera control unit 21 and display of a through image by the electronic viewfinder 26 of the observation optical system are started. Specifically, an exposure operation is performed by the imaging element 22, and pixel data of the imaging pixel 221 is read by the camera control unit 21. Then, the camera control unit 21 generates a through image based on the read data, and the generated through image is sent to the liquid crystal drive circuit 25 and displayed on the electronic viewfinder 26 of the observation optical system. As a result, the user can view the moving image of the subject through the eyepiece lens 27. Note that the generation of the through image and the display of the through image are repeatedly executed at predetermined intervals.

  Next, in step S2, the camera control unit 21 starts a face position specifying process for specifying the position of the person's face. In the present embodiment, first, a template image corresponding to a person's face designated by a user's manual operation or by face recognition processing by the camera control unit 21 is generated. Then, by searching for an area where the degree of coincidence with the generated template image is greater than or equal to a predetermined value, sequentially extracting areas where the degree of coincidence is greater than or equal to a predetermined value, and setting the extracted area as the position of a human face Done. The face position specifying process is repeatedly executed at predetermined intervals.

  In step S3, the camera control unit 21 starts defocus amount detection processing by the phase difference detection method. In the present embodiment, the defocus amount detection processing by the phase difference detection method is performed as follows. That is, first, the camera control unit 21 reads a pair of image data corresponding to a pair of images from the focus detection pixels 222a and 222b constituting the five focus detection pixel rows 22a to 22d of the image sensor 22. In this case, when the position of the person's face is specified in the above-described step S2, only the data from the focus detection pixels corresponding to the specified position of the person's face can be read. .

  Then, the camera control unit 21 performs a filter process on the read pair of image data using a plurality of detection filters having different detection frequency bands, and calculates a plurality of post-filter data for each detection filter, An image shift detection calculation process (correlation calculation process) is executed based on the calculated plurality of post-filter data. Specifically, the camera control unit 21 calculates a plurality of image shift amounts based on a plurality of post-filter data, and further converts the image shift amounts into defocus amounts, thereby using different detection filters. A plurality of obtained defocus amounts are obtained. Then, the camera control unit 21 selects a detection filter having a detection frequency band suitable for the corresponding subject from the plurality of detection filters based on the calculation result in the correlation calculation process, and the selected one of the plurality of defocus amounts is selected. The defocus amount obtained using the detection filter is determined as the final defocus amount. That is, by selecting a detection filter having a detection frequency band suitable for the corresponding subject, the final defocus amount is determined from the plurality of defocus amounts calculated as described above.

  Alternatively, in the present embodiment, when determining the final defocus amount, first, a detection filter having a wave frequency band suitable for the pair of image data is selected in advance based on the read pair of image data. The filter processing is performed using only the selected detection filter, the filtered data is calculated, and the final amount is calculated from the image shift amount calculated from the filtered data obtained using the selected detection filter. It is also possible to adopt a configuration for determining a proper defocus amount.

  The defocus amount detection process using such a phase difference detection method is repeatedly executed at predetermined intervals.

  In step S <b> 4, the camera control unit 21 starts a focus evaluation value calculation process. In the present embodiment, the focus evaluation value calculation process is performed by reading out the pixel output of the imaging pixel 221 of the imaging element 22, extracting a high-frequency component of the read-out pixel output using a high-frequency transmission filter, and accumulating these. Done. In this case, when the position of the person's face is specified in the above-described step S2, only the pixel output of the pixel output of the imaging pixel 221 corresponding to the specified position of the person's face may be read. Good. The focus evaluation value calculation process is repeatedly executed at predetermined intervals.

  In step S5, the camera control unit 21 determines whether the shutter release button provided in the operation unit 28 is half-pressed (the first switch SW1 is turned on). If the first switch SW1 is turned on, the process proceeds to step S6. On the other hand, if the first switch SW1 is not turned on, step S5 is repeated until the first switch SW1 is turned on. That is, until the first switch SW1 is turned on, through-image generation / display, face position specifying processing, defocus amount detection processing using a phase difference detection method, and focus evaluation value calculation processing are repeatedly executed.

  In step S6, a process for determining a focus detection area AFP for detecting the focus state of the optical system is performed. Specifically, when the position of the person's face is specified by the face position specifying process described in step S2, the position of the specified person's face is set in the focus detection area AFP. Alternatively, when the position of the person's face is not specified, a predetermined focus detection position (for example, the focus detection position corresponding to the closest subject or the focus detection position located in the center area of the shooting screen) is optically detected. It is set in the focus detection area AFP for detecting the focus state of the system.

  In step S7, when calculating the defocus amount for the defocus amount detected by the phase difference detection method in the focus detection area AFP for detecting the focus state of the optical system determined in step S6 described above. It is determined whether the detectable frequency band of the used detection filter is equal to or greater than a predetermined value f1. When the detectable frequency band of the detection filter used when calculating the defocus amount is equal to or greater than the predetermined value f1, the process proceeds to step S14. On the other hand, if the detectable frequency band of the detection filter used for detecting the defocus amount is less than the predetermined value f1, the process proceeds to step S8.

  It should be noted that, in a human photographing mode for photographing a human face, a filter with a low frequency band that can be detected is used as a detection filter used when calculating the defocus amount. Therefore, if the spatial frequency of the corresponding subject is low When it can be determined, low frequency components such as skin are often detected in the face of a person. If the area captured by the focus detection pixels 222a and 222b existing at the position corresponding to the focus detection area AFP is a skin portion of a person's face, the skin is focused, Focus is not focused on the subject you want to focus on, so there are many cases where the focus accuracy cannot be obtained sufficiently, and focus detection is based on low frequency components, so focus detection accuracy is low in the first place The problem of becoming a thing may arise.

  On the other hand, in the present embodiment, the frequency band that can be detected by the detection filter used when calculating the defocus amount is equal to or greater than the predetermined value f1, and in the person photographing mode for photographing a person's face. If it can be determined that the spatial frequency of the subject (human face) captured by the focus detection pixels 222a and 222b existing at the position corresponding to the focus detection area AFP is sufficiently high, the process proceeds to step S14. As will be described later, a focusing operation by a phase difference detection method is executed based on the detected defocus amount. On the other hand, the frequency band that can be detected by the detection filter used when calculating the defocus amount is less than the predetermined value f1, and corresponds to the focus detection area AFP in the person photographing mode for photographing a human face. If it is determined that the spatial frequency of the subject (human face) captured by the focus detection pixels 222a and 222b existing at the position is low, the process proceeds to step S8, and a scanning operation described later is executed.

  Here, the predetermined value f1 may be set to a value that can be determined that the spatial frequency of the subject (person) is sufficiently high in the person photographing mode for photographing a person's face, and is not particularly limited. For example, when the number of the plurality of detection filters having different detection frequency bands stored in the camera control unit 21 is 10, using the detection filters up to the third in order from the lowest detection frequency band. When the defocus amount is detected, the spatial frequency of the subject (person's face) is low, so that the configuration can be shifted to a scanning operation described later. In other words, when the defocus amount is detected using the seventh detection filter in order from the highest detection frequency band, the spatial frequency of the subject (person's face) is sufficiently high, A focusing operation based on the phase difference detection method can be performed based on the focus amount.

  In step S7, if it is determined that the detectable frequency band of the detection filter used when calculating the defocus amount is equal to or greater than the predetermined value f1, the process proceeds to step S14, and the phase difference detection method is performed. A focusing operation is performed based on the defocus amount detected by. That is, in step S14, processing for driving the focus lens 32 to the in-focus position is performed based on the defocus amount detected by the phase difference detection method. Specifically, the camera control unit 21 calculates the lens driving amount necessary to drive the focus lens 32 to the in-focus position from the defocus amount detected by the phase difference detection method. The lens driving amount is sent to the lens driving motor 36 via the lens control unit 37. Then, the lens driving motor 36 drives the focus lens 32 to the in-focus position based on the lens driving amount calculated by the camera control unit 21.

  In the present embodiment, the camera control unit 21 repeatedly detects the defocus amount by the phase difference detection method even while the lens driving motor 36 is driven and the focus lens 32 is driven to the in-focus position. If, as a result, a new defocus amount is detected, the camera control unit 21 drives the focus lens 32 based on the new defocus amount.

  In step S13, the camera control unit 21 performs a scanning operation prohibition process as well as a process of driving the focus lens 32 to the in-focus position. Specifically, the camera control unit 21 sends a scan operation prohibition command to the lens control unit 37, and the scan operation is prohibited. The scan operation will be described later.

  When the drive of the focus lens 32 to the in-focus position is completed, the process proceeds to step S16, and focus lock (processing for prohibiting the drive of the focus lens 32) is performed. In this case, the electronic viewfinder 26 may be configured to perform in-focus display.

  On the other hand, if it is determined in step S7 that the detectable frequency band of the detection filter used in calculating the defocus amount is less than the predetermined value f1, the process proceeds to step S8, and in step S8, The camera control unit 21 performs a scan operation start process. In the scanning operation of the present embodiment, the focus lens drive motor 36 scans the focus lens 32 at a predetermined driving speed, and the camera control unit 21 detects the defocus amount by the phase difference detection method and performs focus evaluation. The calculation of the value is performed simultaneously at a predetermined interval, whereby the detection of the in-focus position by the phase difference detection method and the detection of the in-focus position by the contrast detection method are performed simultaneously at the predetermined interval. .

  Specifically, the camera control unit 21 sends a scan drive start command to the lens control unit 37, and the lens control unit 37 drives the focus lens drive motor 36 based on the command from the camera control unit 21 to focus. The lens 32 is scan-driven along the optical axis L1 at a predetermined driving speed. The driving speed of the focus lens 32 when performing the scanning operation is not particularly limited. For example, the driving speed is suitable for detecting the defocus amount by the phase difference detection method, specifically, the phase difference detection method. The maximum speed that can detect the defocus amount, or a speed that is slower than the maximum speed among the speeds that can detect the defocus amount by the phase difference detection method (for example, speed error or detection error). The maximum speed among the speeds in consideration of the above and the like. Further, the scan driving of the focus lens 32 is performed from the infinity end position toward the close end position, or from the close end position toward the infinity end position. In this case, the infinity end position is set to a predetermined position (infinity-side soft limit position) that is closer to the mechanical limit position determined by the structure of the lens barrel 3. Similarly, the closest end position is also set to a predetermined position (closest side soft limit position) on the infinity side of the mechanical limit position determined by the structure of the lens barrel 3.

  The camera control unit 21 reads a pair of image data corresponding to the pair of images from the focus detection pixels 222a and 222b of the image sensor 22 at a predetermined interval while driving the focus lens 32 at a predetermined driving speed. Based on this, the defocus amount is detected by the phase difference detection method, and the pixel output is read from the imaging pixel 221 of the imaging element 22 at a predetermined interval while the focus lens 32 is driven at a predetermined driving speed. Based on this, the focus evaluation value is calculated, and the focus evaluation value at different focus lens positions is thereby acquired, so that the focus position is detected by the contrast detection method.

  In step S9, as a result of the scanning operation performed by the camera control unit 21, in the focus detection area AFP for detecting the focus state of the optical system determined in step S6 described above, the data detected by the phase difference detection method is detected. With regard to the focus amount, it is determined whether or not the frequency band that can be detected by the detection filter used when calculating the defocus amount is equal to or greater than the predetermined value f1 described above. If the detectable frequency band of the detection filter used when calculating the defocus amount is equal to or greater than the predetermined value f1, the process proceeds to step S14, while the detection used when calculating the defocus amount. When the frequency band that can be detected by the filter is less than the predetermined value f1, the process proceeds to step S10.

  In step S10, it is determined whether or not the in-focus position has been detected by the contrast detection method as a result of the scanning operation performed by the camera control unit 21. If the in-focus position can be detected by the contrast detection method, the process proceeds to step S15. If the in-focus position cannot be detected, the process proceeds to step S11.

  In step S <b> 11, the camera control unit 21 determines whether or not the scan operation has been performed for the entire driveable range of the focus lens 32, that is, for the entire region between the infinity end position and the closest end position. When the scan operation is not performed for the entire driveable range of the focus lens 32, the process returns to step S9, and steps S9 to S11 are repeated, so that the scan lens, that is, the focus lens 32 is moved at a predetermined drive speed. While driving, the operation of simultaneously executing the detection of the defocus amount by the phase difference detection method and the detection of the in-focus position by the contrast detection method at a predetermined interval is continuously performed. On the other hand, when the execution of the scan operation is completed for the entire driveable range of the focus lens 32, the process proceeds to step S12.

  As a result of executing the scanning operation, when a defocus amount using a detection filter whose detectable frequency band is equal to or greater than the predetermined value f1 is detected in step S9 (that is, at a position corresponding to the focus detection area AFP). If it is determined that the spatial frequency of the subject (human face) captured by the existing focus detection pixels 222a and 222b is sufficiently high), the process proceeds to step S14, and the phase difference detection method is performed in the same manner as described above. A focusing operation is performed based on the defocus amount detected by. When the driving of the focus lens 32 to the in-focus position is completed, the process proceeds to step S16, and the focus lock is performed.

  As a result of executing the scanning operation, if it is determined in step S10 that the in-focus position has been detected by the contrast detection method, the scanning operation is stopped, and the process proceeds to step S15 where the detection is performed by the contrast detection method. A focusing operation based on the focusing position is performed. That is, in step S15, a focus drive process for driving the focus lens 32 to the focus position is performed based on the focus position detected by the contrast detection method. Here, FIG. 12 is a diagram showing the relationship between the focus lens position and the focus evaluation value and the relationship between the focus lens position and time when the in-focus position is detected by the contrast detection method as a result of the scanning operation. Show. As shown in FIG. 12, at the start of the scanning operation, the focus lens 32 is positioned at P0 shown in FIG. 12, and the focus lens 32 is driven at a predetermined drive speed from P0 toward the near side from P0. The focus evaluation value is acquired. When the focus lens 32 is moved to the position P1 shown in FIG. 12 and the peak position (focus position) of the focus evaluation value is detected (step S10 = Yes), the scanning operation is stopped, Focus drive (step S15) for driving the focus lens 32 to the focus position (position P2 in FIG. 12) is performed. Further, when performing in-focus driving, the camera control unit 21 stops the scanning operation and performs a scanning operation prohibiting process.

  In the present embodiment, when it is determined in step S10 that the in-focus position has been detected by the contrast detection method, the focus lens 32 is driven to the in-focus position based on the detection result by the contrast detection method. In other words, until the drive of the focus lens 32 to the in-focus position is completed, the drive of the focus lens 32 based on the focus detection result by the phase difference detection method is prohibited. That is, after it is determined that the in-focus position can be detected by the contrast detection method, even when the defocus amount can be detected by the phase difference detection method, the focus lens 32 is driven based on the result of the phase difference detection method. Is prohibited. Thereby, the hunting phenomenon of the focus lens 32 can be suppressed.

  When the driving of the focus lens 32 to the in-focus position is completed, the process proceeds to step S16, and the focus lock is performed.

  In the scanning operation of the present embodiment, the above-described steps S9 to S11 are repeatedly executed to detect the defocus amount by the phase difference detection method while the focus lens 32 is scan-driven at a predetermined driving speed. And the detection of the in-focus position by the contrast detection method is simultaneously executed at predetermined intervals. Then, as a result of repeatedly executing steps S9 to S11 described above, the defocus amount detection using the detection filter whose detectable frequency band is equal to or greater than the predetermined value f1 among the phase difference detection method and the contrast detection method. Alternatively, the focus lens 32 is driven to the in-focus position using the focus detection result based on the detection method in which the in-focus position can be detected. Further, as described above, in the scanning operation of the present embodiment, whether or not the defocus amount is detected using the detection filter whose detectable frequency band is equal to or greater than the predetermined value f1 by the phase difference detection method. After the determination (step S9), it is determined whether or not the in-focus position has been detected by the contrast detection method (step S10), thereby detecting the phase difference at the same time in the phase difference detection method and the contrast detection method. Focus detection result by phase difference detection method when detection of defocus amount using detection filter having detectable frequency band equal to or greater than predetermined value f1 by method and detection of focus position by contrast detection method Is adopted in preference to the focus detection result by the contrast detection method.

  Therefore, according to the present embodiment, when it is difficult to detect the focus state of the photographing optical system by the phase difference detection method (for example, when photographing a subject having a different reflectance and a different color, or photographing a low-luminance subject) The focus detection of the photographic optical system is appropriately performed in both cases where it is difficult to detect the focus state of the photographic optical system using a contrast detection method (for example, when shooting a subject with low brightness). Can do. In addition, according to the present embodiment, the defocus amount detection by the phase difference detection method and the in-focus position detection by the contrast detection method are simultaneously performed, and the focus of the photographing optical system is detected by the method in which the focus detection can be performed first. Compared with the conventional technique (that is, a technique in which the focus lens 32 is driven to the vicinity of the in-focus position by the phase difference detection method and then the in-focus position is detected in the vicinity of the in-focus position by the contrast detection method). Thus, the focus adjustment of the photographing optical system can be performed in a short time.

  On the other hand, if it is determined in step S11 that the scan operation has been completed for the predetermined drive range, the process proceeds to step S12. In step S12, as a result of performing the scanning operation, focus detection could not be performed by any of the phase difference detection method and the contrast detection method, so that the scanning operation end processing is performed, and then in step S13 Advancing and out-of-focus processing is performed. As the out-of-focus process, for example, a display indicating out-of-focus is displayed on the electronic viewfinder 26 and the focus lens 32 is driven to a predetermined position.

  As described above, the camera 1 according to this embodiment operates.

  In the above-described operation example, the case where the person shooting mode for shooting a person's face has been selected has been described as an example. However, in addition to the person shooting mode, for example, a macro shooting mode for macro shooting is used. Similarly, when a landscape shooting mode for shooting a landscape is selected, the frequency band that can be detected by the detection filter used when calculating the defocus amount is similarly set to a predetermined value. Only when there is f2 (where f2> f1) or more, based on the detected defocus amount, focusing detection is performed by the phase difference detection method, and the detection filter used when calculating the defocus amount can be detected. If the frequency band is less than a predetermined value f2, it can be configured to shift to a scanning operation. In this case, the predetermined value f2 may be set to a value that can determine that the spatial frequency of the subject is sufficiently high in the macro shooting mode or the landscape shooting mode, and is not particularly limited. When the number of the plurality of detection filters having different detection frequency bands stored in the control unit 21 is 10, the defocus amount is determined using the tenth detection filters in order from the lowest detection frequency band. When it is detected, the spatial frequency of the subject is low, and it can be configured to shift to a scanning operation. In other words, when the defocus amount is detected using the fifth detection filter in order from the highest detection frequency band, the spatial frequency of the subject is sufficiently high, and based on the detected defocus amount. The focusing operation by the phase difference detection method can be executed. In either the macro shooting mode or the landscape shooting mode, the same value may be used as the predetermined value f2, or different values may be used.

  Further, in the above-described operation example, the case where the person photographing mode is selected in advance via the operation unit 28 has been described as an example. However, based on the photographed image acquired by the imaging element 22 by the control unit 21. Of course, it is possible to adopt a configuration in which a person photographing mode and other photographing modes (for example, a macro photographing mode and a landscape photographing mode) are automatically set.

  In this embodiment, for the defocus amount detected by the phase difference detection method, is the frequency band detectable by the detection filter used when calculating the defocus amount equal to or greater than a predetermined value? If it is greater than or equal to a predetermined value, focus driving is performed by the phase difference detection method based on the detected defocus amount. On the other hand, if it is less than the predetermined value, the focus lens 32 Are scanned at a predetermined driving speed, and a scanning operation is performed in which the detection of the in-focus position by the phase difference detection method and the in-focus position detection by the contrast detection method are simultaneously performed at predetermined intervals. Therefore, according to the present embodiment, when the defocus amount is based on a low frequency component having a low spatial frequency such as a skin portion of a human face, the defocus amount based on such a low frequency component is used. If the focus operation is not performed properly, for example, the focus is not focused on the target focus, and the focus may not be sufficient. Since the detection is performed, it is possible to effectively prevent the problem that the focus detection accuracy is low in the first place.

  In particular, according to this embodiment, when the frequency band that can be detected by the detection filter used when calculating the defocus amount is less than a predetermined value, the above-described scanning operation is performed. Even in such a case, the focus accuracy can be made sufficiently high. In addition, according to the present embodiment, only when the frequency band that can be detected by the detection filter used when calculating the defocus amount is equal to or greater than a predetermined value, that is, a high frequency with a high spatial frequency. Only when the defocus amount is based on a component (for example, an eye part of a person's face), focusing by the phase difference detection method is executed based on the defocus amount, and thus the focus is achieved by the phase difference detection method. When the operation is executed, the focus accuracy can be sufficient.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, for the defocus amount detected by the phase difference detection method, the frequency band that can be detected by the detection filter used when calculating the defocus amount is a predetermined value. In the case where it is less, the configuration in which the scan operation is executed is exemplified, but the process of prohibiting the driving of the focus lens 32 based on the defocus amount detected by the phase difference detection method without executing the scan operation is performed. It is good also as a structure which performs. When the process of prohibiting the driving of the focus lens 32 is performed as described above, the detection of the defocus amount used when calculating the defocus amount is performed again by detecting the defocus amount by the phase difference detection method. When the detectable frequency band is equal to or greater than a predetermined value, the driving of the focus lens 32 based on the defocus amount detected by the phase difference detection method is permitted, thereby the phase difference detection method. It is sufficient to adopt a configuration in which focusing drive by is executed.

  In the above-described embodiment, the scan operation is performed when the detectable frequency band of the detection filter used when calculating the defocus amount is less than a predetermined value. However, for example, when the reliability of the detected defocus amount is less than a predetermined value, the detectable frequency band of the detection filter used when calculating the defocus amount is determined in advance. Even if the value is equal to or greater than the predetermined value, the scanning operation may be executed. Alternatively, in such a case, instead of executing the scan operation, a process for prohibiting the driving of the focus lens 32 based on the defocus amount detected by the phase difference detection method may be performed. In addition, as a case where the reliability of the defocus amount is less than a predetermined value, for example, based on the detected defocus amount, the in-focus position exists on the infinity side in the optical axis direction or on the close side. The value can be set so that it can be determined whether or not it exists.

  In the above-described embodiment, when a plurality of focus detection positions corresponding to the position of the person's face are detected when determining the focus detection area AFP for detecting the focus state of the optical system, a plurality of focus detection positions are detected. When the focus detection area AFP for detecting the focus state of the optical system is selected from the focus detection position, a frequency band that can be detected by the detection filter used for calculating the defocus amount is determined in advance. Alternatively, the focus detection area AFP may be selected except for the focus detection position that is less than the predetermined value. By adopting such a configuration, it is possible to exclude in advance a focus detection position that captures a low-frequency component having a low spatial frequency, such as a skin portion, of a human face, and thereby the time required for focus detection Can be shortened.

  Furthermore, in the above-described embodiment, when the frequency band that can be detected by the detection filter used when calculating the defocus amount is equal to or larger than a predetermined value, the detected defocus amount is based on the detected defocus amount. In this example, the focus driving is performed by the phase difference detection method, and the scan operation is executed when it is less than the predetermined value. The value of the focus amount is greater than or equal to a predetermined value df1, and the detectable frequency band of the detection filter used when calculating the defocus amount is a predetermined value f3 (f3>). When f2> f1) or more, the configuration may be such that the scan operation is executed. That is, the value of the defocus amount is relatively large as a predetermined value df1 or more, and therefore the amount of blur is large. Therefore, a detection filter used for calculating the defocus amount has a relatively low frequency band. While a detectable filter is considered to be used, when a detection filter capable of detecting a high frequency band capable of detecting high frequency components is used, the obtained defocus amount is considered to be extremely unreliable. Judgment can be made. Therefore, in such a case, the focus drive based on the detected defocus amount is not executed, but the scan drive is executed instead, while effectively preventing the in-focus state. High focus accuracy can be obtained. Note that the predetermined value df1 is not particularly limited, and can be set to a value at which the amount of blur can be determined to be sufficiently large, and can be changed according to the aperture value of the aperture 34. The predetermined value f3 is not particularly limited, but may be set to a value that can detect a high-frequency component having a sufficiently high frequency by using a detection filter capable of detecting a frequency band equal to or higher than the predetermined value f3.

DESCRIPTION OF SYMBOLS 1 ... Digital camera 2 ... Camera body 21 ... Camera control part 22 ... Imaging device 221 ... Imaging pixel 222a, 222b ... Focus detection pixel 3 ... Lens barrel 32 ... Focus lens 36 ... Focus lens drive motor 37 ... Lens control part

Claims (14)

An imaging unit that captures an image by an optical system having a focus adjustment optical system and outputs an image signal corresponding to the captured image;
A phase difference detection unit that detects a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference; and
A contrast detection unit that detects a focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the imaging unit;
A storage unit that stores a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the phase difference detection unit;
A scene determination unit for determining a shooting scene;
A drive unit that drives the focus adjustment optical system in the optical axis direction of the optical system;
A controller that controls the drive of the focus adjustment optical system by controlling the drive unit, and
The phase difference detection unit acquires an image shift signal corresponding to an image plane shift amount by the optical system using a phase difference, and acquires the image shift signal using the plurality of filters stored in the storage unit. After filtering the image shift signal and calculating a plurality of filter processing signals processed by the plurality of filters, among the plurality of filters used for calculating the plurality of filter processing signals, the acquired image shift signal A filter capable of detecting a suitable frequency band is selected, and the deviation amount is detected based on a filter processing signal obtained using the selected filter among the plurality of filter processing signals,
As a result of causing the phase difference detection unit to detect the focus state of the optical system, the control unit determines, by the scene determination unit, a frequency band that can be detected by the filter selected by the phase difference detection unit. Whether the frequency band of the selected filter is a frequency band different from the specific frequency band is determined. In addition, the focus detection is performed by causing the phase difference detection unit and the contrast detection unit to detect the focus state of the optical system while driving the focus adjustment optical system in a predetermined direction. apparatus. An imaging unit that captures an image by an optical system having a focus adjustment optical system and outputs an image signal corresponding to the captured image;
A phase difference detection unit that detects a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference; and
A contrast detection unit that detects a focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the imaging unit;
A storage unit that stores a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the phase difference detection unit;
A scene determination unit for determining a shooting scene;
A drive unit that drives the focus adjustment optical system in the optical axis direction of the optical system;
A controller that controls the drive of the focus adjustment optical system by controlling the drive unit, and
The phase difference detection unit acquires an image shift signal corresponding to an image plane shift amount by the optical system using the phase difference, and detects a frequency band suitable for the image shift signal from the plurality of filters. Select a possible filter, detect the shift amount based on a filter processing signal obtained by filtering the acquired image shift signal by the selected filter,
As a result of causing the phase difference detection unit to detect the focus state of the optical system, the control unit determines, by the scene determination unit, a frequency band that can be detected by the filter selected by the phase difference detection unit. Whether the frequency band of the selected filter is a frequency band different from the specific frequency band is determined. In addition, the focus detection is performed by causing the phase difference detection unit and the contrast detection unit to detect the focus state of the optical system while driving the focus adjustment optical system in a predetermined direction. apparatus. An imaging unit that captures an image by an optical system having a focus adjustment optical system and outputs an image signal corresponding to the captured image;
A phase difference detection unit that detects a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference; and
A storage unit that stores a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the phase difference detection unit;
A scene determination unit for determining a shooting scene;
A drive unit that drives the focus adjustment optical system in the optical axis direction of the optical system;
A controller that controls the drive of the focus adjustment optical system by controlling the drive unit, and
The phase difference detection unit acquires an image shift signal corresponding to an image plane shift amount by the optical system using a phase difference, and acquires the image shift signal using the plurality of filters stored in the storage unit. After filtering the image shift signal and calculating a plurality of filter processing signals processed by the plurality of filters, among the plurality of filters used for calculating the plurality of filter processing signals, the acquired image shift signal A filter capable of detecting a suitable frequency band is selected, and the deviation amount is detected based on a filter processing signal obtained using the selected filter among the plurality of filter processing signals,
As a result of causing the phase difference detection unit to detect the focus state of the optical system, the control unit determines, by the scene determination unit, a frequency band that can be detected by the filter selected by the phase difference detection unit. Whether the frequency band of the selected filter is a frequency band different from the specific frequency band, and whether the frequency band of the selected filter is different from the specific frequency band. A focus detection apparatus that prohibits control based on the amount of deviation detected by a detection unit. An imaging unit that captures an image by an optical system having a focus adjustment optical system and outputs an image signal corresponding to the captured image;
A phase difference detection unit that detects a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference; and
A storage unit that stores a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the phase difference detection unit;
A scene determination unit for determining a shooting scene;
A drive unit that drives the focus adjustment optical system in the optical axis direction of the optical system;
A controller that controls the drive of the focus adjustment optical system by controlling the drive unit, and
The phase difference detection unit acquires an image shift signal corresponding to an image plane shift amount by the optical system using the phase difference, and detects a frequency band suitable for the image shift signal from the plurality of filters. Select a possible filter, detect the shift amount based on a filter processing signal obtained by filtering the acquired image shift signal by the selected filter,
As a result of causing the phase difference detection unit to detect the focus state of the optical system, the control unit determines, by the scene determination unit, a frequency band that can be detected by the filter selected by the phase difference detection unit. Whether the frequency band of the selected filter is a frequency band different from the specific frequency band, and whether the frequency band of the selected filter is different from the specific frequency band. A focus detection apparatus that prohibits control based on the amount of deviation detected by a detection unit. In the focus detection apparatus in any one of Claims 1-4,
When the frequency band of the filter selected by the phase difference detection unit is within the specific frequency band, the control unit causes the drive unit to determine whether the frequency difference is detected by the phase difference detection unit. A focus detection apparatus for driving the focus adjustment optical system. In the focus detection apparatus in any one of Claims 1-5,
The focus detection apparatus, wherein the scene determination unit determines a shooting scene based on a scene set by a user via an operation member or a captured image captured by the imaging unit. In the focus detection apparatus in any one of Claims 1-6,
The control unit sets the specific frequency band to a frequency band equal to or higher than a predetermined first threshold when the scene determination unit determines that the shooting scene is a scene for shooting a human face. Feature focus detection device. In the focus detection apparatus in any one of Claims 1-6,
The control unit sets the specific frequency band to a frequency band equal to or higher than a predetermined first threshold when the scene determination unit determines that the shooting scene is a scene for shooting a human face, When the scene determination unit determines that the shooting scene is a macro shooting scene or a scene shooting scene, the specific frequency band is set to a frequency equal to or higher than a predetermined second threshold higher than the first threshold. A focus detection apparatus characterized in that a band is set. In the focus detection apparatus according to any one of claims 1 to 8,
The phase difference detection unit detects the shift amount for each of a plurality of focus detection positions set in the shooting screen,
The control unit excludes a deviation amount detected using a filter capable of detecting a frequency band different from the specific frequency band among the plurality of deviation amounts detected for each of the plurality of detection positions, A focus detection apparatus that causes the phase difference detection unit to detect a focus state of the optical system. An imaging unit that captures an image by an optical system having a focus adjustment optical system and outputs an image signal corresponding to the captured image;
A phase difference detection unit that detects a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference; and
A contrast detection unit that detects a focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the imaging unit;
A storage unit that stores a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the phase difference detection unit;
A scene determination unit for determining a shooting scene;
A drive unit that drives the focus adjustment optical system in the optical axis direction of the optical system;
A controller that controls the drive of the focus adjustment optical system by controlling the drive unit, and
The phase difference detection unit acquires an image shift signal corresponding to an image plane shift amount by the optical system using a phase difference, and acquires the image shift signal using the plurality of filters stored in the storage unit. After filtering the image shift signal and calculating a plurality of filter processing signals processed by the plurality of filters, among the plurality of filters used for calculating the plurality of filter processing signals, the acquired image shift signal A filter capable of detecting a suitable frequency band is selected, and the deviation amount is detected based on a filter processing signal obtained using the selected filter among the plurality of filter processing signals,
The control unit causes the phase difference detection unit to detect the focus state of the optical system. As a result, the amount of deviation detected by the phase difference detection unit is equal to or greater than a predetermined value, and the phase difference detection It is determined whether the frequency band that can be detected by the filter selected by the unit is a frequency band higher than a predetermined specific frequency band, and the deviation amount is equal to or greater than the predetermined value, and the selected frequency band is selected. When the frequency band that can be detected by the filter is a frequency band higher than the specific frequency band, the driving unit drives the focus adjustment optical system in a predetermined direction, and the phase difference detection unit and A focus detection apparatus that performs scan driving for causing the contrast detection unit to detect a focus state of the optical system. An imaging unit that captures an image by an optical system having a focus adjustment optical system and outputs an image signal corresponding to the captured image;
A phase difference detection unit that detects a focal state of the optical system by detecting a shift amount of an image plane by the optical system using a phase difference; and
A contrast detection unit that detects a focus state of the optical system by calculating an evaluation value related to the contrast of the image by the optical system based on the image signal output by the imaging unit;
A storage unit that stores a plurality of filters having different frequency bands that can be detected and used for detection of a focus state by the phase difference detection unit;
A drive unit that drives the focus adjustment optical system in the optical axis direction of the optical system;
A controller that controls the drive of the focus adjustment optical system by controlling the drive unit, and
The phase difference detection unit acquires an image shift signal corresponding to an image plane shift amount by the optical system using the phase difference, and outputs the image shift signal from a plurality of filters having different detectable frequency bands. Select a filter capable of detecting a suitable frequency band, and detect the shift amount based on a filter processing signal obtained by filtering the acquired image shift signal with the selected filter,
The control unit causes the phase difference detection unit to detect the focus state of the optical system. As a result, the amount of deviation detected by the phase difference detection unit is equal to or greater than a predetermined value, and the phase difference detection It is determined whether the frequency band that can be detected by the filter selected by the unit is a frequency band higher than a predetermined specific frequency band, and the deviation amount is equal to or greater than the predetermined value, and the selected frequency band is selected. When the frequency band that can be detected by the filter is a frequency band higher than the specific frequency band, the driving unit drives the focus adjustment optical system in a predetermined direction, and the phase difference detection unit and A focus detection apparatus that performs scan driving for causing the contrast detection unit to detect a focus state of the optical system. The focus detection apparatus according to claim 10 or 11,
The focus detection apparatus, wherein the control unit sets the predetermined value according to an aperture value of the optical system. In the focus detection apparatus according to any one of claims 1 to 12,
The focus detection device, wherein the phase difference detection unit is provided on a light receiving surface of the imaging unit.   The imaging device provided with the focus detection apparatus in any one of Claims 1-13.

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