JP5966262B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus.

  By storing zoom tracking data indicating the amount of movement of the focus adjustment lens according to the movement of the zoom lens in the lens barrel, and driving the focus adjustment lens based on the zoom tracking data when driving the zoom lens. A zoom tracking technique that corrects a focal position that has changed due to a change in zoom magnification is known (see, for example, Patent Document 1).

JP-A-3-228036

  However, in the prior art, zoom tracking is not performed according to the driving state of the focus adjustment lens, so that the focus adjustment lens may cause a hunting phenomenon and the usability is inferior. There was a problem.

  The problem to be solved by the present invention is to provide an imaging apparatus capable of appropriately adjusting the focus 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] an imaging apparatus according to the present onset bright drives the focusing lens in the optical axis direction, a focus adjustment unit for adjusting the focus state of the optical system, by driving the zoom lens in the optical axis direction, a zoom magnification And a first focus detection unit that detects a focus state of the optical system by calculating a focus evaluation value in a different focus state while driving the focus adjustment lens in the optical axis direction. A zoom tracking unit that controls zoom tracking that causes the focus adjustment unit to move the focus adjustment lens according to the movement of the zoom lens, and the focus adjustment lens to detect a focus state of the optical system. A control unit that prohibits zoom tracking, a second focus detection unit that detects a focus state of the optical system using a phase difference, and a shutter release button. When a push operation is performed, based on the focus detection result by the first focus detection unit or the second focus detection unit, the focus adjustment unit drives the focus adjustment lens to a focus position, and then A first mode setting unit that sets a first mode for prohibiting driving of the focus adjustment lens based on a focus detection result while the shutter release button is half-pressed, and the control unit includes the first mode setting unit. When the first mode is set and the focus adjustment unit drives the focus adjustment lens to the in-focus position based on the focus detection result by the first focus detection unit or the second focus detection unit. After the focusing driving operation is performed, zoom tracking is permitted when the driving of the focusing lens based on the focus detection result is prohibited.

  According to the imaging apparatus of the present invention, it is possible to appropriately adjust the focus of the optical system.

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 III part 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. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is a diagram showing a zoom tracking table showing the relationship between the zoom lens position and the focus lens position. FIG. 10 is a flowchart showing the operation when the AF-F mode is selected. FIG. 11 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 when the AF-F mode is selected. FIG. 12 is a diagram illustrating the relationship between the focus lens position and time when the AF-F mode is selected. FIG. 13 is a flowchart showing an operation when the AF-S mode or the AF-A mode is selected. FIG. 14 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 when the AF-S mode is selected. FIG. 15 is a diagram illustrating the relationship between the focus lens position and time when the AF-S mode is selected.

  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 photographing optical system including lenses 31, 32, 33, 34 and a diaphragm 35.

  The lens 33 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 33 is movably provided along the optical axis L 1 of the lens barrel 3, and its position is adjusted by the focus lens driving motor 331 while its position is detected by the focus lens encoder 332.

  The specific configuration of the moving mechanism along the optical axis L1 of the focus lens 33 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 33 is fixed. The end of the lens frame is fitted into the helicoid groove. Then, by rotating the rotating cylinder by the focus lens driving motor 331, the focus lens 33 fixed to the lens frame moves straight along the optical axis L1.

  As described above, the focus lens 33 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 331 as its drive source is the lens. The lens barrel 3 is provided. The focus lens drive motor 331 and the rotating cylinder are connected by a transmission composed of a plurality of gears, for example, and when the drive shaft of the focus lens driving motor 331 is driven to rotate in any one direction, it is transmitted to the rotating cylinder at a predetermined gear ratio. Then, when the rotary cylinder rotates in any one direction, the focus lens 33 fixed to the lens frame moves straight in any direction of the optical axis L1. When the drive shaft of the focus lens drive motor 331 is rotationally driven in the reverse direction, the plurality of gears constituting the transmission also rotate in the reverse direction, and the focus lens 33 moves straight in the reverse direction of the optical axis L1. .

  The position of the focus lens 33 is detected by a focus lens encoder 332. As described above, the position of the focus lens 33 in the direction of the optical axis L1 correlates with the rotation angle of the rotary cylinder, and can be obtained by detecting the relative rotation angle of the rotary cylinder with respect to the lens barrel 3, for example.

  As the focus lens encoder 332 of this embodiment, the rotation of a rotating disk connected to the rotational drive of a rotating cylinder is detected by an optical sensor such as a photo interrupter, and a pulse signal corresponding to the number of rotations is output. The brush contact provided on either one of the encoder pattern on the surface of the flexible printed wiring board provided on one of the fixed cylinder and the rotating cylinder is brought into contact with the moving amount of the rotating cylinder (in the optical axis direction even in the rotation direction). Any of which can detect a change in the contact position according to the detection circuit by a detection circuit can be used.

  The focus lens 33 can move in the direction of the optical axis L1 from the end on the camera body (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 33 detected by the focus lens encoder 332 is sent to the camera control unit 21 to be described later via the lens control unit 36, and the focus lens drive motor 331 calculates based on this information. The drive position of the focus lens 33 is driven by being sent from the camera control unit 21 via the lens control unit 36.

  The lens 32 is a zoom lens, and can move in the optical axis L1 direction to adjust the shooting magnification of the shooting optical system. Similarly to the focus lens 33 described above, the position of the zoom lens 32 is adjusted by the zoom lens driving motor 321 while the position thereof is detected by the zoom lens encoder 322. The position of the zoom lens 32 is adjusted by operating a zoom button provided on the operation unit 28 or operating a zoom ring (not shown) provided on the camera barrel 3. The moving mechanism along the optical axis L1 of the zoom lens 32 can be the same as the moving mechanism of the focus lens 31 described above. The configurations of the zoom lens encoder 322 and the zoom lens drive motor 321 can also be the same as those of the focus lens encoder 332 and the focus lens drive motor 331 described above.

  The diaphragm 35 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 adjust the amount of blur. The adjustment of the aperture diameter by the diaphragm 35 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 36. Further, the set aperture diameter is input from the camera control unit 21 to the lens control unit 36 by a manual operation by the operation unit 28 provided in the camera body 2. The aperture diameter of the aperture 35 is detected by an aperture sensor (not shown), and the lens controller 36 recognizes the current aperture diameter.

  The lens control unit 36 detects the position of the zoom lens 32 detected by the zoom lens encoder 322. When the zoom lens 32 is driven, the lens control unit 36 moves the focus lens 33 according to the amount of movement of the zoom lens 32. It is driven to perform zoom tracking control for fine adjustment of focus.

  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 36 through an electrical signal contact unit 41 provided on the mount unit 4, receives lens information from the lens control unit 36, and defocuses to the lens control unit 36. 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 button, and switches between an autofocus mode / manual focus mode and an autofocus mode. In particular, the AF-S mode / AF-A mode / AF-F mode can be switched. 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.

  Here, the AF-S mode means that after the shutter release button is half-pressed, the focus lens 33 is driven based on the focus detection result to perform focusing driving, and the position of the focus lens 33 adjusted once is set. This is a mode in which the subject is fixed and photographed at the focus lens position. The AF-S mode is a mode suitable for still image shooting, and is normally selected when still image shooting is performed. In the AF-A mode, after the shutter release button is half-pressed, the focus lens 33 is driven based on the focus detection result to drive the focus, and then the shutter release button is half-pressed. In this mode, the focus state is repeatedly detected while the focus state changes, and the focus lens 33 is scanned when the focus state changes. The AF-A mode is a mode suitable for still image shooting, and is normally selected when still image shooting is performed. Further, in the AF-F mode, regardless of whether or not the shutter release button is operated, the focus lens 33 is driven based on the focus detection result to perform the focus drive, and thereafter the focus state is repeatedly detected, and the focus is detected. When the state changes, this is a mode in which the focus lens 33 is scan-driven. The AF-F mode is a mode suitable for moving image shooting, and is usually selected when moving image shooting is performed.

  In the present embodiment, the switch for switching the autofocus mode may be provided with a switch for switching the one-shot mode / continuous mode. In this case, when the one-shot mode is selected by the photographer, the AF-S mode is set, and when the continuous mode is selected by the photographer, the photographing mode is stationary. When the image shooting mode is set, the AF-A mode is set. When the shooting mode is the moving image shooting mode, the AF-F mode is set.

  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 image sensor 22, and FIG. 3 is a front view schematically showing the arrangement of the focus detection pixels 222a and 222b by enlarging the III part of 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.

  In addition, on the imaging surface of the imaging element 22, focus detection pixel rows 22 a to 22 e in which focus detection pixels 222 a and 222 b 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 22e shown in FIG.

  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. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 3. The focus detection pixels 222 a-1, 222 b-1, 222 a-2, and 222 b-2 that are arranged in the vicinity of the photographing optical axis L 1 and adjacent to each other are 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. 8 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. 8 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. 8, the arrangement direction of the focus detection pixels 222a-1, 222b-1, 222a-2, 222b-2 coincides with the arrangement direction of the pair of distance measuring pupils 351, 352.

  As shown in FIG. 8, 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. 8, the photoelectric conversion unit 2222a-1 of the focus detection pixel 222a-1 is formed on the microlens 2221a-1 by the 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. Then, by applying an image shift detection calculation process such as a correlation calculation process or a phase difference detection process to the intensity distribution data, an image shift amount by a so-called phase difference detection method can be detected.

  Then, a conversion calculation is performed on the obtained image shift amount according to the center-of-gravity interval of the pair of distance measuring pupils, thereby obtaining a focal plane corresponding to the current focal plane (the position corresponding to the position of the microlens array on the planned focal plane) The deviation of the focal plane in the detection area), that is, the defocus amount can be obtained.

  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, for example, by extracting a high-frequency component of an image output from the imaging pixel 221 of the image sensor 22 using a high-frequency transmission filter and integrating the extracted high-frequency components to detect a focus voltage. It can also be obtained by extracting high-frequency components using two high-frequency transmission filters having different cutoff frequencies and integrating them to detect the focus voltage.

  Then, the camera control unit 21 sends a control signal to the lens control unit 36 to drive the focus lens 33 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 33 is determined as the in-focus position. Note that this in-focus position is obtained when, for example, the focus evaluation value is calculated while the focus lens 33 is driven, and 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.

  Here, in FIG. 2, the first area and the second area in the shooting screen are displayed in correspondence with the image sensor 22 (note that the area surrounded by the one-dot chain line shown in FIG. 1 area, and the outer area located around the first area is the second area). The first area in the imaging screen corresponds to an area including the focus detection pixel rows 22a to 22e in the image sensor 22, and thereby the focus state of the optical system is determined by the phase difference detection method and the contrast detection method. This is an area that can be detected. Further, as shown in FIG. 2, the second area in the shooting screen is an area that is located around the first area in the shooting screen and does not include the focus detection pixel rows 22 a to 22 e in the image sensor 22. This is an area where the focus state of the optical system can be detected only by the contrast detection method. Therefore, in the present embodiment, as shown in FIG. 2, the camera control unit 21 detects the phase difference when the focus detection area AFP for performing focus detection exists in the first region in the shooting screen. The focus state can be detected by the method and the contrast detection method. On the other hand, when the focus detection area AFP exists in the second region of the shooting screen, the focus state can be detected by the contrast detection method. .

  Furthermore, the camera control unit 21 sends the zoom control prohibiting signal for prohibiting the zoom tracking control and the zoom tracking permission signal for permitting the zoom tracking control to the lens control unit 36, so that the lens control unit 36. Control of permission / prohibition of zoom tracking control executed by. In other words, the lens control unit 36 detects the position of the zoom lens 32 detected by the zoom lens encoder 322 when receiving the zoom tracking permission signal, and when the zoom lens 32 is driven, Depending on the amount of movement, the focus lens 33 is driven to perform zoom tracking control for finely adjusting the focus. Specifically, when detecting the driving of the zoom lens 32, the lens control unit 36 uses a zoom tracking table indicating the relationship between the position of the zoom lens 32 and the position of the focus lens 33 for each shooting distance. Thus, the drive amount of the focus lens 33 corresponding to the movement amount of the zoom lens 32 is calculated. Then, by sending the calculated drive amount of the focus lens 33 to the focus lens drive motor 331, the focus lens 33 is driven to perform zoom tracking control for finely adjusting the focus.

  On the other hand, when the lens control unit 36 receives the zoom tracking prohibition signal, even if the zoom lens encoder 322 detects the driving of the zoom lens 32, the lens control unit 36 does not execute such zoom tracking control. Zoom tracking control is performed when a tracking permission signal is received.

  Next, an operation example of the camera 1 according to the present embodiment will be described. First, in the present embodiment, an operation example when the AF-F mode, which is a mode suitable for moving image shooting, is selected will be described. FIG. 10 is a flowchart showing the operation when the AF-F mode is selected. Note that since the AF-F mode is a mode that is usually selected when shooting a moving image, the following description will be given specifically illustrating a scene in which the AF-F mode is selected at the time of moving image shooting. The following operations are started when, for example, the camera 1 is turned on and the moving image shooting start button is turned on.

  First, in step S101, the camera control unit 21 performs processing for permitting zoom tracking. Specifically, a zoom tracking permission signal is transmitted from the camera control unit 21 to the lens control unit 36, whereby the zoom tracking control by the lens control unit 36 is permitted. When the zoom tracking control is permitted, the zoom tracking control is performed when the lens control unit 36 detects the driving of the zoom lens 32. That is, when the driving of the zoom lens 32 is detected, the lens control unit 36 determines the driving amount of the focus lens 33 according to the moving amount of the zoom lens 32 based on the zoom tracking table shown in FIG. By calculating and sending the calculated drive amount to the focus lens drive motor 331, the focus lens 33 is driven, and fine adjustment of the focus is thereby performed.

  Next, in step S102, the camera control unit 21 starts defocus amount calculation processing by the phase difference detection method. In the present embodiment, the calculation process of the defocus amount 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 22e of the image sensor 22. Then, the camera control unit 21 executes image shift detection calculation processing (correlation calculation processing) based on the read pair of image data, and images at the focus detection positions corresponding to the five focus detection pixel rows 22a to 22e. The shift amount is calculated, and the image shift amount is converted into a defocus amount. Further, the camera control unit 21 evaluates the reliability of the calculated defocus amount. Note that the reliability of the defocus amount is evaluated based on, for example, the degree of coincidence and contrast of a pair of image data. The defocus amount calculation process using such a phase difference detection method is repeatedly executed at predetermined intervals.

  In step S103, the camera control unit 21 starts a focus evaluation value calculation process. In the present embodiment, the focus evaluation value calculation process reads out the pixel output of the imaging pixel 221 of the imaging device 22, extracts a high-frequency component of the read-out pixel output using a high-frequency transmission filter, integrates it, and focuses on it. This is done by detecting the voltage. The focus evaluation value calculation process is repeatedly executed at predetermined intervals.

  In step S104, the camera control unit 21 starts tracking calculation processing for tracking the subject. In the present embodiment, first, a template image corresponding to a specific subject to be tracked designated by a user's manual operation or by subject recognition processing by the camera control unit 21 is generated. Then, an area where the degree of coincidence with the generated template image is equal to or greater than a predetermined value is searched, areas where the degree of coincidence is equal to or greater than a predetermined value are sequentially extracted, and the extracted area is designated as a focus detection area AFP (see, for example, FIG. 2). ). The tracking calculation process is repeatedly executed at a predetermined interval.

  In step S105, the camera control unit 21 determines whether or not the defocus amount has been calculated in the focus detection area AFP set based on the tracking calculation process by the phase difference detection method. If the defocus amount can be calculated, it is determined that distance measurement is possible, and the process proceeds to step S111. On the other hand, if the defocus amount cannot be calculated, it is determined that distance measurement is impossible, and the process proceeds to step S106. In the present embodiment, even when the defocus amount can be calculated in the focus detection area AFP set based on the tracking calculation process, the defocus amount is not reliable even when the calculated defocus amount is low. It is assumed that the focus amount cannot be calculated, and the process proceeds to step S106. In the present embodiment, for example, when the subject has a low contrast, the subject is an ultra-low brightness subject, or the subject is an ultra-high brightness subject, it is determined that the reliability of the defocus amount is low. . In addition, when the focus detection area AFP set based on the tracking calculation process is located in the first region shown in FIG. 2, it is possible to detect the focus state of the optical system by the phase difference detection method. When the focus detection area AFP is located in the second region shown in FIG. 2, the focus state of the optical system cannot be detected by the phase difference detection method. In this case, the defocus amount cannot be calculated. As a result, the process proceeds to step S106.

  In step S105, the above determination is performed using the result of the most recent defocus amount calculation process. However, the defocus amount is continuously calculated in the most recent predetermined number of defocus amount calculation processes. If not, or continuously, if the reliability of the defocus amount is low, it is determined that ranging is impossible, and the process proceeds to step S106. Conversely, in the defocus amount calculation process of the most recent predetermined number of times. If the defocus amount is calculated even once, it may be determined that distance measurement is possible and the process proceeds to step S111.

  If it is determined in step S105 that the defocus amount in the focus detection area AFP has been calculated and it is determined that the distance can be measured, the process proceeds to step S111, and a result based on the defocus amount calculated by the phase difference detection method is obtained. In order to perform the focus drive (step S112), a zoom tracking prohibition signal is transmitted from the camera control unit 21 to the lens control unit 36, thereby prohibiting the zoom tracking control by the lens control unit 36. In other words, in the present embodiment, zoom tracking is prohibited during focus driving based on the defocus amount calculated by the phase difference detection method, and even when the driving of the zoom lens 32 is detected, Accordingly, the operation of driving the focus lens 33 according to the movement amount of the zoom lens 32 is not executed.

  Next, in step S112 following step S111, focusing drive based on the defocus amount calculated by the phase difference detection method is performed. Specifically, in step S112, processing for driving the focus lens 33 to the in-focus position is performed based on the defocus amount calculated by the phase difference detection method in step S102. Specifically, the camera control unit 21 calculates and calculates the lens driving amount necessary to drive the focus lens 33 to the in-focus position from the defocus amount calculated by the phase difference detection method. The lens driving amount is sent to the lens driving motor 36 via the lens control unit 36. Then, the lens driving motor 36 drives the focus lens 33 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 calculates the defocus amount by the phase difference detection method even while the lens driving motor 36 is driven and the focus lens 33 is driven to the in-focus position. As a result, when a new defocus amount is calculated, the camera control unit 21 drives the focus lens 33 based on the new defocus amount.

  When the focus lens 33 is driven to the in-focus position, the process proceeds to step S115, and since the focus drive based on the defocus amount calculated by the phase difference detection method is completed, the prohibition of zoom tracking is canceled by the camera control unit 21. For this purpose, a zoom tracking permission signal is transmitted to the lens control unit 36, whereby the zoom tracking control by the lens control unit 36 is permitted. In this case, if the zoom lens 32 is driven while zoom tracking is prohibited, the zoom tracking control is permitted, and then the zoom lens 32 is driven according to the drive amount of the zoom lens 32 when zoom tracking is prohibited. Thus, the focus lens 33 is driven.

  Next, in step S116, it is determined whether or not the focus state of the optical system has changed. For example, when the defocus amount by the phase difference detection method repeatedly calculated by the camera control unit 21 changes by a predetermined value or more, or when the defocus amount cannot be calculated, or is also repeatedly calculated by the camera control unit 21. When the focus evaluation value is changed by a predetermined value or more, it can be determined that the focus state of the optical system has changed. If it is determined that the focus state of the optical system has changed, the process returns to step S105, and the operation for driving the focus lens 33 to the in-focus position is performed again. On the other hand, if the focus state of the optical system has not changed, a predetermined end operation, for example, a power-off operation of the camera 1 or a video shooting end operation is performed (step S117), or the focus of the optical system Until the state is changed (step S116), the focus lens 33 is stopped at the current lens position and waits.

  On the other hand, if it is determined in step S105 that the defocus amount cannot be calculated in the focus detection area AFP by the phase difference detection method, the process proceeds to step S106, and the camera control unit 21 performs a scan operation (step S107). ˜S110), a zoom tracking prohibition signal is transmitted from the camera control unit 21 to the lens control unit 36, whereby zoom tracking control by the lens control unit 36 is prohibited. That is, in the present embodiment, during the scanning operation, zoom tracking is prohibited, and even when the driving of the zoom lens 32 is detected, zoom tracking control, that is, the focus lens 33 corresponding to the amount of movement of the zoom lens 32 is set. The driving operation is not executed.

  In step S107 following step S106, the camera control unit 21 performs a scan operation start process. In the scan operation of this embodiment, the focus lens drive motor 36 scans the focus lens 33 while the camera control unit 21 calculates the defocus amount and the focus evaluation value by the phase difference detection method. Thus, 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 simultaneously performed at predetermined intervals.

  Specifically, the camera control unit 21 sends a scan drive start command to the lens control unit 36, and the lens control unit 36 drives the focus lens drive motor 36 based on the command from the camera control unit 21 to focus. The lens 33 is scan-driven along the optical axis L1. Note that the scan driving of the focus lens 33 is performed from the infinity end position toward the close end position, or from the close end position toward the infinity end position.

  Then, while driving the focus lens 33, the camera control unit 21 reads out 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 predetermined intervals. The phase difference detection method calculates the defocus amount, evaluates the reliability of the calculated defocus amount, and drives the focus lens 33 to drive the pixel output from the imaging pixel 221 of the imaging element 22 at predetermined intervals. Reading is performed, and based on this, a focus evaluation value is calculated, thereby acquiring a focus evaluation value at a different focus lens position, thereby detecting a focus position by a contrast detection method. In the present embodiment, when the focus detection area AFP set based on the tracking calculation process is located in the first region shown in FIG. 2, the focus state of the optical system is detected by the phase difference detection method. On the other hand, when the focus detection area AFP is located in the second region shown in FIG. 2, the focus state of the optical system cannot be detected by the phase difference detection method. Therefore, when the focus detection area AFP is located in the second region shown in FIG. 2, the contrast detection method is not performed in the scan operation of the present embodiment without detecting the focus position by the phase difference detection method. Only the in-focus position is detected.

  In step S108, it is determined whether the defocus amount in the focus detection area AFP can be calculated by the phase difference detection method as a result of the scanning operation performed by the camera control unit 21. If the defocus amount can be calculated, it is determined that distance measurement is possible and the process proceeds to step S112. On the other hand, if the defocus amount cannot be calculated, it is determined that distance measurement is not possible and the process proceeds to step S109. . In step S108, as in step S105 described above, even when the defocus amount can be calculated, the defocus amount cannot be calculated if the reliability of the calculated defocus amount is low. It is assumed that the process proceeds to step S109. When the focus detection area AFP is located in the second region shown in FIG. 2, the focus state of the optical system cannot be detected by the phase difference detection method. In this case, the defocus amount is calculated. Assuming that it was not possible, the process proceeds to step S109.

  In step S109, it is determined whether or not the in-focus position in the focus detection area AFP 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 in the focus detection area AFP can be detected by the contrast detection method, the process proceeds to step S113. If the in-focus position cannot be detected, the process proceeds to step S110.

  In step S <b> 110, the camera control unit 21 determines whether or not the scan operation has been performed for the entire range in which the focus lens 33 can be driven, 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 33, the process returns to step S108, and steps S108 to S110 are repeated, so that the phase difference is detected while driving the focus lens 33. The operation of simultaneously executing the calculation of the defocus amount by the detection method and the detection of the in-focus position by the contrast detection method at predetermined intervals is continuously performed. On the other hand, if the scan operation has been completed for the entire driveable range of the focus lens 33, the process proceeds to step S114.

  As a result of executing the scanning operation, when it is determined in step S108 that the defocus amount can be calculated by the phase difference detection method, the scanning operation is stopped, and the process proceeds to step S112. Focusing driving based on the defocus amount calculated by the phase difference detection method is performed. Even in this case, zoom tracking is prohibited during the focus driving based on the defocus amount calculated by the phase difference detection method because the zoom tracking is prohibited in step S106. Even when the driving of the zoom lens 32 is detected, the zoom tracking control, that is, the operation of driving the focus lens 33 according to the movement amount of the zoom lens 32 is not executed. When the drive of the focus lens 33 to the in-focus position is completed, the process proceeds to step S115, and the focus control based on the defocus amount calculated by the phase difference detection method is completed. Therefore, the camera control unit 21 performs zoom tracking. In order to cancel the prohibition, a zoom tracking permission signal is transmitted to the lens control unit 36, whereby the zoom tracking control by the lens control unit 36 is permitted.

  As a result of executing the scanning operation, when it is determined in step S109 that the in-focus position has been detected by the contrast detection method, the scanning operation is stopped, and the process proceeds to step S113, where the detection is performed by the contrast detection method. Focusing driving based on the focusing position is performed. That is, in step S113, a focus drive process for driving the focus lens 33 to the focus position is performed based on the focus position detected by the contrast detection method. In this case as well, zoom tracking is prohibited in step S106, so zoom tracking is prohibited during focus drive based on the focus position detected by the contrast detection method, and zoom Even when the driving of the lens 32 is detected, zoom tracking control, that is, the operation of driving the focus lens 33 according to the movement amount of the zoom lens 32 is not executed.

  FIG. 11 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 when the in-focus position is detected by the contrast detection method as a result of the scanning operation. Show. In FIG. 11, the change in the focus evaluation value with respect to the position of the focus lens 33 is indicated by a solid line. As shown in FIG. 11, at the start of the scanning operation (time t0 to t1), the focus lens 33 is located at P0 shown in FIG. 11, and the focus lens from P0 toward the near side from the infinity side. The focus evaluation value is acquired while driving 33 (time t1 to t2). When the focus lens 33 is moved to the position P1 shown in FIG. 11 and the peak position (focus position) of the focus evaluation value is detected (step S109 = Yes), the scanning operation is stopped. Focus drive (step S113) for driving the focus lens 33 to the focus position (position P2 in FIG. 11) is performed (time t2 to t3).

  In this embodiment, when it is determined in step S109 that the in-focus position has been detected by the contrast detection method, the focus lens 33 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 33 to the in-focus position is completed, the drive of the focus lens 33 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 calculated by the phase difference detection method, the focus lens 33 is driven based on the result of the phase difference detection method. Is prohibited. Thereby, the hunting phenomenon of the focus lens 33 can be suppressed.

  Further, in the scanning operation of the present embodiment, the above-described steps S108 to S110 are repeatedly executed, and while the focus lens 33 is driven to scan, the calculation of the defocus amount by the phase difference detection method and the comparison by the contrast detection method. The detection of the focal position is simultaneously performed at a predetermined interval. As a result of repeatedly executing steps S108 to S110 described above, the focus detection result by the detection method in which the defocus amount is calculated or the in-focus position can be detected first among the phase difference detection method and the contrast detection method. The focus lens 33 is driven to the in-focus position. Further, as described above, in the scanning operation of this embodiment, after determining whether or not the defocus amount can be calculated by the phase difference detection method (step S108), the in-focus position can be detected by the contrast detection method. If the phase difference detection method and the contrast detection method can calculate the defocus amount and detect the in-focus position at the same time by determining whether or not the focus position has been detected, the focus by the phase difference detection method is determined. The detection result is adopted in preference to the focus detection result by the contrast detection method.

  When the driving of the focus lens 33 to the in-focus position is completed, the process proceeds to step S115, and since the in-focus driving based on the in-focus position detected by the contrast detection method is completed, the camera control unit 21 prohibits zoom tracking. In order to cancel the zoom tracking permission signal, a zoom tracking permission signal is transmitted to the lens control unit 36, whereby the zoom tracking control by the lens control unit 36 is permitted, and the process proceeds to step S116. In step S116, it is determined whether or not the focus state of the optical system has changed. If it is determined that the focus state of the optical system has changed, the process returns to step S105, and the focus lens 33 is moved again. An operation for driving to the in-focus position is performed. On the other hand, if the focus state of the optical system has not changed, a predetermined end operation, for example, a power-off operation of the camera 1 or a video shooting end operation is performed (step S117), or the focus of the optical system Until the state is changed (step S116), the focus lens 33 is stopped at the current lens position and waits.

  On the other hand, if it is determined in step S110 that the scan operation has been completed for the entire driveable range of the focus lens 33, the process proceeds to step S114. In step S114, as a result of the scanning operation, focus detection could not be performed by any of the phase difference detection method and the contrast detection method, so the scanning operation was terminated and the focus lens 33 was determined in advance. A process of driving to a predetermined position is performed.

  When the focus lens 33 is driven to a predetermined position, the process proceeds to step S115, and the scanning operation is completed. Therefore, the camera control unit 21 causes the camera control unit 21 to cancel the zoom tracking prohibition. A tracking permission signal is transmitted to the lens control unit 36, whereby the zoom tracking control by the lens control unit 36 is permitted, and the process proceeds to step S116. In step S116, it is determined whether or not the focus state of the optical system has changed. If it is determined that the focus state of the optical system has changed, the process returns to step S105, and the focus lens 33 is moved again. An operation for driving to the in-focus position is performed. On the other hand, if the focus state of the optical system has not changed, a predetermined end operation, for example, a power-off operation of the camera 1 or a video shooting end operation is performed (step S117), or the focus of the optical system Until the state is changed (step S116), the focus lens 33 is stopped at the current lens position and waits.

  In the present embodiment, the operation is performed as described above when the AF-F mode, which is a mode suitable for moving image shooting, is selected.

  That is, in the present embodiment, when the AF-F mode is set, zoom tracking is permitted when the focus lens 33 is stopped (time t0 to t1) as shown in FIG. When it is determined that the defocus amount is not calculated by the phase difference detection method (step S105 = No), zoom tracking is prohibited (step S106), and zoom tracking is prohibited. A scanning operation (steps S107 to S110) is executed (time t1 to t2). When the in-focus position (position P2) can be detected by the contrast detection method (step S109 = Yes), in-focus driving is performed with zoom tracking prohibited (time t2 to t3). ). Next, when in-focus driving is performed, zoom tracking is permitted (step S115), whether the power-off operation of the camera 1 or the end of moving image shooting is performed (step S117), or the focus state of the optical system is changed. Until the change (step S116), the focus lens 33 is stopped at the current lens position and waits (time t3 to t4). In this case, when driving of the zoom lens 32 is detected, the lens control unit 36 performs zoom tracking control, that is, an operation of driving the focus lens 33 according to the movement amount of the zoom lens 32. It will be.

  When the focus lens 33 is in a standby state while being stopped at the current lens position, for example, as shown in FIG. 11, when the in-focus position changes from P2 to P3 (step S116), again. Then, it is determined whether or not the defocus amount is calculated by the phase difference detection method (step S105). As a result, when it is determined that the defocus amount is not calculated by the phase difference detection method (step S105 = No), zoom tracking is prohibited (step S106), and the scan operation is performed again in a state where zoom tracking is prohibited. (Steps S107 to S110) are executed (time t4 to t5). Similarly, when the in-focus position (position P3) can be detected by the contrast detection method (step S109 = Yes), in-focus driving is performed with zoom tracking prohibited (time). t5 to t6). Next, when in-focus driving is performed, zoom tracking is permitted (step S115), whether the power-off operation of the camera 1 or the end of moving image shooting is performed (step S117), or the focus state of the optical system is changed. Until the change is made (step S116), the focus lens 33 is stopped at the current lens position and waits (time t6 to t7).

  In the present embodiment, when the AF-F mode is set, zoom tracking is permitted when the focus lens 33 is stopped (time t10 to t11) as shown in FIG. When it is determined that the defocus amount has been calculated by the phase difference detection method (step S105 = Yes), zoom tracking is prohibited (step S111), and zoom tracking is prohibited. Focus drive (step S112) based on the defocus amount detected by the phase difference detection method is executed (time t11 to t12). Next, when the focus lens 33 is driven to the in-focus position (position P11) as a result of the focus drive, zoom tracking is permitted (step S115), and the power-off operation of the camera 1 and the end operation of moving image shooting are performed. The focus lens 33 is stopped at the current lens position (time t12 to t13) until it is performed (step S117) or until the focus state of the optical system changes (step S116). In this case, when driving of the zoom lens 32 is detected, the lens control unit 36 performs zoom tracking control, that is, an operation of driving the focus lens 33 according to the movement amount of the zoom lens 32. It will be.

  When the focus lens 33 is stopped at the current lens position and is on standby, for example, as shown in FIG. 12, when the focus position is changed from P11 to P12 (step S116), again. Then, it is determined whether or not the defocus amount is calculated by the phase difference detection method (step S105). As a result, if it is determined that the defocus amount has been calculated by the phase difference detection method (step S105 = Yes), zoom tracking is prohibited (step S111), and the phase difference is again performed in a state where zoom tracking is prohibited. Focus drive (step S112) based on the defocus amount detected by the detection method is executed (time t13 to t14). Next, when in-focus driving is performed, zoom tracking is permitted (step S115), whether the power-off operation of the camera 1 or the end of moving image shooting is performed (step S117), or the focus state of the optical system is changed. Until the change is made (step S116), the focus lens 33 is stopped at the current lens position and waits (time t14 to t15).

  Next, an operation example when the AF-S mode or AF-A mode, which is a mode suitable for still image shooting, is selected will be described. FIG. 13 is a flowchart showing an operation when the AF-S mode or the AF-A mode is selected. Further, the following operation is started, for example, when the camera 1 is turned on.

  First, in steps S201 to S203, zoom tracking is permitted (step S201), defocus amount calculation processing using a phase difference detection method (step S202), and focus as in steps S101 to S104 of FIG. Processing for starting evaluation value calculation processing (step S203) and tracking calculation processing (step S204) for tracking the subject is performed.

  In step S205, 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 S206. On the other hand, if the first switch SW1 is not turned on, step S205 is repeated until the first switch SW1 is turned on. That is, the defocus amount calculation process, the focus evaluation value calculation process, and the tracking calculation process by the phase difference detection method are repeatedly executed until the first switch SW1 is turned on.

  In step S206, as in step 105 of FIG. 10 described above, it is determined whether or not the defocus amount has been calculated in the focus detection area AFP set based on the tracking calculation process by the phase difference detection method. It is. If the defocus amount can be calculated, it is determined that distance measurement is possible, and the process proceeds to step S212. On the other hand, if the defocus amount cannot be calculated, it is determined that distance measurement is impossible, and the process proceeds to step S207.

  If it is determined in step S206 that the defocus amount in the focus detection area AFP has been calculated and it is determined that distance measurement is possible, the process proceeds to step S212, and zoom tracking is performed in the same manner as in step S111 in FIG. The process proceeds to step S213, and focusing drive based on the defocus amount calculated by the phase difference detection method is performed in the same manner as step S112 in FIG. 10 described above.

  On the other hand, if it is determined in step S206 that the defocus amount cannot be calculated in the focus detection area AFP by the phase difference detection method, the process proceeds to step S207, and the same as step S106 in FIG. 10 described above. Then, a process for prohibiting zoom tracking is performed, and the process proceeds to step S208, where a scan operation start process is performed in the same manner as steps S107 to S110 in FIG. 10 described above. The

  If the defocus amount in the focus detection area AFP can be calculated by the phase difference detection method as a result of the scanning operation (step S209 = Yes), the process proceeds to step S213 and is calculated by the phase difference detection method. Focusing driving based on the defocus amount is performed. As a result of the scanning operation, when the in-focus position in the focus detection area AFP can be detected by the contrast detection method (step S210 = Yes), the process proceeds to step S214, and the above-described step S113 in FIG. Similarly, focusing driving based on the focusing position detected by the contrast detection method is performed. Even in this case, since processing for prohibiting zoom tracking is performed in step S106, focusing is being performed based on the defocus amount calculated by the phase difference detection method (step S213), and the contrast detection method is used. In any case of in-focus driving based on the detected in-focus position (step S214), zoom tracking is prohibited, and even when driving of the zoom lens 32 is detected, zoom tracking control, that is, the zoom lens 32 is detected. The operation of driving the focus lens 33 according to the amount of movement is not executed.

  On the other hand, if it is determined in step S211 that the scan operation has been completed for the entire driveable range of the focus lens 33, the process proceeds to step S215. In step S215, as a result of the scanning operation, focus detection could not be performed by either the phase difference detection method or the contrast detection method, so the scanning operation was terminated and the focus lens 33 was determined in advance. A process of driving to a predetermined position is performed.

  In step S213, the focus lens 33 is driven to the in-focus position based on the defocus amount calculated by the phase difference detection method, and in step S214, based on the in-focus position detected by the contrast detection method. After the focus lens 33 is driven to the in-focus position, or after the process of driving the focus lens 33 to a predetermined position in step S215 is performed, the process proceeds to step S216, and the camera control unit 21 In order to cancel the prohibition of zoom tracking, a zoom tracking permission signal is transmitted to the lens control unit 36, whereby the zoom tracking control by the lens control unit 36 is permitted, and the process proceeds to step S217.

  In step S217, it is determined whether or not the autofocus mode is set to the AF-S mode. If the AF-S mode is set, the process proceeds to step S218. If the AF-A mode is set instead of the AF-S mode, the process proceeds to step S220.

  If the AF-S mode is set, the process proceeds to step S218, and in step S218, focus lock for fixing the focus lens 33 at the current lens position is performed. Then, in step S219, it is determined whether or not the shutter release button provided in the operation unit 28 has been fully pressed (second switch SW2 is turned on). If the second switch SW2 is turned on, step S219 is performed. Proceeding to S222, a subject image is shot. On the other hand, when the second switch SW2 is not turned on, the focus lens 33 is fixed at the current lens position, and the process waits until the second switch SW2 is turned on.

  On the other hand, if the AF-A mode is set, the process advances to step S220 to determine whether or not the focus state of the optical system has changed. For example, when the defocus amount by the phase difference detection method repeatedly calculated by the camera control unit 21 changes by a predetermined value or more, or when the defocus amount cannot be calculated, or is also repeatedly calculated by the camera control unit 21. When the focus evaluation value is changed by a predetermined value or more, it can be determined that the focus state of the optical system has changed. If it is determined that the focus state of the optical system has changed, the process returns to step S206. If the first switch SW1 is turned on, the processes of steps S207 to S215 are performed again as described above. Then, an operation for driving the focus lens 33 to the in-focus position is performed. On the other hand, when the focus state of the optical system has not changed, the focus lens 33 is moved until the second switch SW2 is turned on (step S221) or until the focus state of the optical system changes (step S220). Wait while stopping at the current lens position.

  In this embodiment, when the AF-S mode or the AF-A mode, which is a mode suitable for still image shooting, is selected, the above operation is performed.

  That is, in the present embodiment, when the AF-S mode is set, zoom tracking is permitted when the focus lens 33 is stopped (time t20 to t21) as shown in FIG. When the first switch SW1 is turned on (step S205) and it is determined that the defocus amount is not calculated by the phase difference detection method (step S206 = No), zoom tracking is prohibited (step S207). ) In a state where zoom tracking is prohibited, the scanning operation (steps S208 to S211) is executed (time t21 to t22). When the in-focus position (position P2) can be detected by the contrast detection method (step S210 = Yes), in-focus driving is performed with zoom tracking prohibited (time t22 to t23). ). Next, when in-focus driving is performed, zoom tracking is permitted (step S216), and in-focus locking (S218) is performed. At this time, even when the in-focus position changes from P2 to P3 at time t24, the focus lens 33 is not driven, but if the drive of the zoom lens 32 is detected, the camera control unit 21, the zoom tracking control, that is, the operation of driving the focus lens 33 according to the movement amount of the zoom lens 32 is executed.

  In the present embodiment, when the AF-S mode is set, zoom tracking is permitted when the focus lens 33 is stopped (time t30 to t31) as shown in FIG. When the first switch SW1 is turned on (step S205) and it is determined that the defocus amount is calculated by the phase difference detection method (step S206 = Yes), zoom tracking is prohibited (step S212). ) In a state where zoom tracking is prohibited, focusing drive (step S213) based on the defocus amount detected by the phase difference detection method is executed (time t31 to t32). Next, when the focus lens 33 is driven to the focus position (P11 position) as a result of focus drive, zoom tracking is permitted (step S216) and focus lock (S218) is set. At this time, even when the in-focus position changes from P11 to P12 at time t33, if the focus lens 33 is not driven while the drive of the zoom lens 32 is detected, the camera control unit 21, the zoom tracking control, that is, the operation of driving the focus lens 33 according to the movement amount of the zoom lens 32 is executed.

  Further, in the present embodiment, when the AF-A mode is set, the operation is performed as shown in FIGS. 11 and 12 as in the AF-F mode described above.

  In the present embodiment, when the focus lens 33 is driven to scan, the focus lens 33 is driven to focus based on the defocus amount calculated by the phase difference detection method, and the focus lens 33 is detected by the contrast detection method. When the zoom lens 32 is driven when the focus lens is driven based on the in-focus position, zoom tracking control for finely adjusting the focus by driving the focus lens 33 according to the movement amount of the zoom lens 32. Therefore, it is possible to effectively prevent the occurrence of a problem that the focus lens 33 causes the hunting phenomenon, thereby improving the feeling of use and improving the focus adjustment accuracy.

  In addition, in this embodiment, after the scanning drive of the focus lens 33 is completed and after the focusing drive of the focus lens 33 is completed, the zoom tracking control is permitted to perform zoom scanning control. Even when the zoom lens 32 is driven, the zoom tracking control is executed after the scan drive or the focus drive, so that the zoom lens 32 is driven during the scan drive or the focus drive. The focus shift can be properly eliminated.

  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, when the AF-F mode is set, the focus drive based on the defocus amount calculated by the phase difference detection method and the focus position detected by the contrast detection method are used. Although the focus lens 33 is stopped at the in-focus position after performing the in-focus driving based on the above, the wobbling driving for reciprocating the focus lens 33 in the vicinity of the in-focus position is performed. Good. In this case, since the problem of the hunting phenomenon of the focus lens 33 does not occur even if the zoom tracking control is performed when the focus lens 33 is driven by wobbling, the zoom tracking control is not performed during the wobbling drive. By setting the permission, it is possible to appropriately eliminate the focus shift caused by driving the zoom lens 32 without impairing the feeling of use.

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 ... Zoom lens 321 ... Zoom lens drive motor 33 ... Focus lens 331 ... Focus Lens drive motor 36 ... Lens control unit

Claims (4)

A focus adjustment unit that adjusts the focus state of the optical system by driving the focus adjustment lens in the optical axis direction;
A zoom magnification change unit for changing the zoom magnification by driving the zoom lens in the optical axis direction;
A first focus detection unit that detects a focus state of the optical system by calculating a focus evaluation value in a different focus state while driving the focus adjustment lens in the optical axis direction;
A zoom tracking unit that controls zoom tracking that causes the focus adjustment unit to move the focus adjustment lens according to the movement of the zoom lens;
A control unit that prohibits zoom tracking when the focus adjustment lens is driven to detect a focus state of the optical system;
A second focus detection unit that detects a focus state of the optical system using a phase difference;
When the shutter release button is half-pressed, the focus adjustment unit drives the focus adjustment lens to the in-focus position based on the focus detection result by the first focus detection unit or the second focus detection unit. And a first mode setting unit for setting a first mode for prohibiting the driving of the focus adjustment lens based on a focus detection result while the shutter release button is half-pressed,
The control unit is set to the first mode, and based on a focus detection result by the first focus detection unit or the second focus detection unit, the focus adjustment unit causes the focus adjustment lens to An imaging device that permits zoom tracking when the focus adjustment lens is driven based on a focus detection result after a focus drive operation for driving the lens to a focus position is performed. The imaging device according to claim 1,
Based on the focus detection result by the first focus detection unit or the second focus detection unit, the focus adjustment unit changes the focus state of the optical system even after the focus adjustment unit is driven to the in-focus position by the focus adjustment unit. And a second mode setting unit for setting a second mode for driving the focus adjustment lens ,
The control unit is set to the second mode, and the focus adjustment unit drives the focus adjustment lens to a focus position based on a focus detection result by the second focus detection unit. An imaging device that prohibits zoom tracking. The imaging device according to claim 2 ,
The control unit is a case where the second mode is set, and the focus adjustment unit drives the focus adjustment lens to a focus position based on a focus detection result by the first focus detection unit. An imaging device that permits zoom tracking after a focus drive operation is performed. In the imaging device in any one of Claims 1-3 ,
The control unit is an image pickup apparatus that permits zoom tracking when the wobbling drive of the focus adjustment lens is performed.

Images