JP5948769B2 - interchangeable lens - Google Patents

Description

  The present invention relates to a lens barrel and a camera body.

  Conventionally, a lens barrel that transmits lens information to a camera body is known (see, for example, Patent Document 1).

JP 2008-258558 A

  However, in the prior art, since the focus adjustment lens is controlled without considering the interval at which the lens information is transmitted to the camera body, the focus adjustment lens may not be appropriately controlled.

The problem to be solved by the present invention is to provide an interchangeable lens capable of appropriately controlling a focus lens.

  The present invention solves the above problems by the following means. In the following description, reference numerals corresponding to the drawings showing the embodiment of the present invention are given and described. However, the reference numerals are only for facilitating the understanding of the invention and are not intended to limit the invention. .

[1] interchangeable lens according to the present embodiment forms condition includes a receiver for receiving a request signal of the lens information from the camera body, after the receiving unit receives the request signal of the lens information, the lens information, the camera A transmission unit that transmits to the body, a determination unit that determines whether a reception interval of the request signal for the lens information from the camera body is a second interval that is longer than a predetermined first interval, and the lens information When the request signal reception interval is determined to be the first interval, the focus lens is driven at a speed equal to or lower than a predetermined first speed, and the lens information request signal reception interval is the second interval. A control unit that drives the focus lens at a speed equal to or lower than a second speed that is slower than the first speed when it is determined that the distance is an interval;

ADVANTAGE OF THE INVENTION According to this invention, the interchangeable lens which can control a focus lens appropriately can be provided.

FIG. 1 is a block diagram showing a camera according to the present embodiment. FIG. 2 is a front view showing a focus detection area on the 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 flowchart showing the operation of the camera 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 (hereinafter simply referred to as a camera 1) according to the present embodiment includes a camera body 2 and a lens barrel 3. 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 aperture diameter corresponding to the aperture value calculated in the automatic exposure mode from the camera control unit 21 via the lens control unit 37. In addition, the aperture diameter corresponding to the set photographing aperture value is input from the camera control unit 21 to the lens control unit 37 by 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 stores lens information unique to the lens such as the focal length of the optical system in a memory provided in the lens control unit 37. In the present embodiment, in addition to the focal length stored in the memory of the lens control unit 37, information on the aperture value based on the position of the focus lens 32 detected by the encoder 35 and the aperture diameter of the aperture 34 is lens information. Is transmitted to the camera control unit 21 of the camera body 2.

  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 memory 24 that is a recording medium. As the memory 24, any of a removable card type memory and a built-in type memory can be used. An infrared cut filter for cutting infrared light and an optical low-pass filter for preventing image aliasing noise are disposed in front of the imaging surface of the image sensor 22. 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.

  The camera body 2 is provided with a camera control unit 21. 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 transmits a request signal for requesting lens information to the lens control unit 37, and acquires lens information from the lens control unit 37 in response to the request signal. 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. Is output to the liquid crystal driving circuit 25 and the 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 a shutter release button, a moving image shooting button, and an input switch for the photographer to set various operation modes of the camera 1, and can switch between an autofocus mode and a manual focus mode. The operation unit 28 can also switch between the still image shooting mode / moving image shooting mode. 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. The information on the still image shooting mode or the moving image shooting mode set by the operation unit 28 is also transmitted to the lens control unit 37 by the camera control unit 21.

  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, focus detection pixel rows 22a, 22b, and 22c in which focus detection pixels 222a and 222b are arranged in place of the above-described imaging pixels 221 at the center of the image pickup surface of the image pickup element 22 and three positions that are symmetrical from the center. Is provided. As shown in FIG. 3, one focus detection pixel column includes a plurality of focus detection pixels 222 a and 222 b that are alternately arranged adjacent to each other in a horizontal row (22 a, 22 c, 22 c). Yes. 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 22c shown in FIG. 2 are not limited to the illustrated positions, and may be any one or two, or may be arranged at four or more positions. it can. In actual focus detection, the photographer manually operates the operation unit 28 from among a plurality of focus detection pixel rows 22a to 22c, and selects a desired focus detection pixel row as a focus detection position. You can also

  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.

  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 It shows that light beams AB1-1, AB2-1, AB1-2, and AB2-2 irradiated from the distance measuring pupils 341 and 342 of the exit pupil 34 are received, respectively. 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 341 and 342 are respectively received.

  Here, the exit pupil 34 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 341 and 342 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 341, 342.

  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 Projected onto the exit pupil 34 separated from the lenses 2221a-1, 2221b-1, 2221a-2, 2221b-2 by the distance measurement distance D, and the projection shape forms the distance measurement pupils 341, 342.

  In other words, on the exit pupil 34 at the distance measurement distance D, the microlens and the photoelectric conversion unit in each focus detection pixel so that the projection shapes (the distance measurement pupils 341 and 342) of the photoelectric conversion unit of each focus detection pixel match. 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 341 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 341, 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 342, 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 342, 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 converted into the distance measurement pupil 341, respectively. Of the pair of images formed on the focus detection pixel row by the focus detection light fluxes that pass through each of the distance measurement pupil 341 and the distance measurement pupil 342. 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 at the detection position, 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 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 operation example of the camera 1 according to the present embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing the operation of the camera 1 according to this embodiment.

  First, in step S101, the camera control unit 21 determines whether a moving image is being captured. In the present embodiment, the camera control unit 21 shoots a moving image when, for example, a photographer presses a moving image shooting button provided in the operation unit 28 and starts shooting a moving image. Can be determined. If it is determined that a moving image has been shot, the process proceeds to step S108. If it is determined that a moving image has not been shot, the process proceeds to step S102.

  In step S102, since it is determined that a still image is to be taken, the camera control unit 21 starts transmitting a lens information request signal at a predetermined first interval (for example, 1 msec interval). Accordingly, a request signal for lens information is transmitted to the lens barrel 3 at a predetermined first interval, and lens information is transmitted from the lens barrel 3 to the camera body 2 in response to the request signal. As a result, the camera control unit 21 of the camera body 2 can acquire lens information from the lens barrel 3 at the first interval. The lens information transmitted from the lens barrel 3 includes information such as the lens position of the focus lens 32, the focal length, and the aperture value.

  In step S103, the camera control unit 21 determines whether or not the shutter release button provided in the operation unit 28 is half-pressed (the first switch SW1 is turned on). If the shutter release button has been pressed halfway, the process proceeds to step S104. If the shutter release button has not been pressed halfway, the process waits in step S103.

  In step S104, the camera control unit 21 performs focus detection calculation. Specifically, a light beam from the optical system is received by the image sensor 22, and a pair of focus detection pixels 222 a and 222 b that constitute the three focus detection pixel rows 22 a to 22 c of the image sensor 22 by the camera control unit 21. A pair of image data corresponding to the first image is read out. In this case, when a specific focus detection position is selected by a manual operation of the photographer, only data from focus detection pixels corresponding to the focus detection position may be read. Then, the camera control unit 21 performs 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 three focus detection pixel rows 22a to 22c. The shift amount is calculated, and the image shift amount is converted into a defocus amount.

  In step S105, the camera control unit 21 performs focus adjustment processing for driving the focus lens 32 to the in-focus position at a predetermined first drive speed. Here, the first drive speed is the maximum speed among the speeds for driving the focus lens 32 in the case of transmitting a lens information request signal at the first interval, such as when shooting a still image. The maximum speed among the speeds at which the focus lens 32 can be driven can be set. In the present embodiment, the first drive speed is set to a second drive speed (moving image) to be described later in consideration of a response from when the shutter release button is pressed halfway until the focus lens 32 is driven to the in-focus position. The maximum speed among the speeds for driving the focus lens 32 when taking a picture.

  Specifically, in step S105, the camera control unit 21 calculates the lens driving amount necessary for driving the focus lens 32 to the in-focus position based on the defocus amount calculated in step S104. The calculated lens driving amount and the predetermined first driving speed are sent to the focus lens driving motor 36 via the lens control unit 37. Thereby, the focus lens 32 is driven by the focus lens drive motor 36 to the in-focus position at the first drive speed based on the calculated lens drive amount.

  When the driving of the focus lens 32 to the in-focus position is completed, the process proceeds to step S106, and the camera control unit 21 determines whether or not the shutter release button has been fully pressed (the second switch SW2 is turned on). When the second switch SW2 is on, the process proceeds to step S107. On the other hand, when the second switch SW2 is not on, the process waits at step S106. In step S106, when the second switch SW2 is not on, the process may return to step S103.

  In step S107, a still image is captured. Specifically, an exposure operation for capturing a still image is performed by the image sensor 22, and image data captured by the image sensor 22 is read by the camera control unit 21. Then, after the camera control unit 21 performs predetermined image processing on the read image data, the image processed image data is stored in the memory 24.

  If it is determined in step S101 that a moving image has been shot, the process proceeds to step S108. Here, in the shooting of moving images, in recent years, the amount of image data to be processed has increased due to higher definition of moving images, and in addition, highly efficient image compression processing, audio recording compression processing, recording media Since the storage process is continuously performed, the processing load of the camera 1 tends to increase as compared to the case of taking a still image. Therefore, in step S108, the camera control unit 21 determines whether the lens information request signal can be transmitted at the first interval. If it is determined that the processing load at the time of capturing a moving image is large and the transmission of the lens information request signal cannot be performed at the first interval, a step is performed to calculate a transmission interval at which the lens information request signal can be transmitted. On the other hand, if it is determined that the processing load for capturing a moving image is small and the lens information request signal can be transmitted at the first interval, the process proceeds to step S111.

  In step S109, since it is determined that the processing load when capturing a moving image is large and the transmission of the lens information request signal cannot be performed at the first interval, the camera control unit 21 determines that the moving image is captured. In the processing load, a process of calculating a second interval that is an interval at which the lens information request signal can be transmitted is performed. Note that the second interval is calculated as a time interval longer than the first interval when a still image with a small processing load on the camera 1 is taken.

  In step S110, the camera control unit 21 starts transmitting the lens information request signal at the second interval calculated in step S109. Thereby, a request signal for lens information is transmitted from the camera body 2 to the lens barrel 3 at every second interval, and from the lens barrel 3 according to the request signal for lens information transmitted from the camera body 2. Lens information is transmitted to the camera body 2. As a result, the camera control unit 21 can acquire lens information from the lens barrel 3 at the second interval.

  On the other hand, if it is determined in step S108 that the processing load for capturing a moving image is small and the lens information request signal can be transmitted at the first interval, the process proceeds to step S111. In step S111, as in step S102, transmission of a lens information request signal is started at a predetermined first interval.

  In step S112, as in step S103, it is determined whether or not the shutter release button provided in the operation unit 28 is half-pressed (the first switch SW1 is turned on), and the shutter release button is half-pressed. In step S116, on the other hand, if the shutter release button is not half pressed, the process proceeds to step S113.

  In step S113, as in step S104, focus detection calculation is performed. In step S114, the camera control unit 21 performs focus adjustment processing for driving the focus lens 32 to the in-focus position at the moving image shooting speed. Note that the moving image shooting speed is better than the driving speed of the focus lens 32 when shooting a still image in order to improve the appearance of the moving image and to reduce the driving sound of the focus lens 32. With speed.

  In step S115, a moving image is captured. Specifically, an exposure operation for capturing a moving image is performed by the image sensor 22, and image data captured by the image sensor 22 is read by the camera control unit 21. Then, the read image data is stored in the memory 24 by the camera control unit 21. Note that while the focus lens 32 is driven to the in-focus position by the focus adjustment process in step S114, the moving image is captured in step S115 at a predetermined frame rate.

  On the other hand, if it is determined in step S112 that the shutter release button has been pressed halfway, the process proceeds to step S116. Here, in the present embodiment, when the shutter release button is pressed halfway when shooting a moving image, when the shutter release button is pressed halfway when shooting a still image, Similarly, when the in-focus position is detected, the focus lens 32 is driven to the in-focus position at a speed faster than the moving image shooting speed, and further, when the shutter release button is fully pressed, the in-focus position is detected. Processing for capturing a still image at the position is performed. Below, step S116-S123 which performs said process is demonstrated.

  That is, first, in step S116, the camera control unit 21 determines whether or not transmission of a lens information request signal is performed at the second interval. If the transmission of the lens information request signal is performed at the second interval, the process proceeds to step S117. On the other hand, if the transmission of the lens information request signal is performed at the first interval, the process proceeds to step S122. move on.

  In step S117, the camera control unit 21 calculates the second drive speed. Here, the second drive speed is the maximum speed among the speeds for driving the focus lens 32 in the case where a request signal for lens information is transmitted at the second interval, such as when a moving image is being shot. It can be calculated as described below.

That is, in the present embodiment, the second drive speed V2 of the focus lens 32 can be calculated based on the following formula (1).
Second drive speed V2 = V1 × (1 / N) (1)
In the above formula (1), V1 is the first driving speed that is the maximum driving speed of the focus lens 32 when the lens information request signal is transmitted at the first interval, and N is the lens information request signal. This is the number of times that a request signal for lens information can be transmitted at the first interval while the lens is transmitted once at the second interval.

  For example, when a still image is captured, a lens information request signal is transmitted every 1 msec. When a moving image is captured, a lens information request signal is transmitted every 3 msec. Since the lens information request signal can be transmitted three times at the first interval (1 msec interval) while taking a still image while the lens information request signal is transmitted once at the second interval (3 msec interval). In this scene example, the second drive speed V2 is calculated as 1/3 of the first drive speed V1.

  In step S118, the focus detection calculation is performed in the same manner as in steps S104 and S113. In subsequent step S119, the camera control unit 21 focuses the focus lens 32 at the second driving speed calculated in step S117. A focus adjustment process for driving to the position is performed. When the driving of the focus lens 32 to the in-focus position is completed, the process proceeds to step S120, and it is determined whether or not the shutter release button is fully pressed (the second switch SW2 is turned on). If the second switch SW2 is on, the process proceeds to step S121, and a still image is captured in step S121. On the other hand, if the second switch SW2 is not on in step S120, the process proceeds to step S115, and a moving image is taken. Note that while the focus lens 32 is driven to the in-focus position by the focus adjustment process in step S119, the moving image capturing in step S115 is repeatedly performed at a predetermined frame rate.

  If it is determined in step S116 that the lens information request signal is transmitted at the first interval, the process proceeds to step S122. In step S122, focus detection calculation is performed in the same manner as in step S104. In subsequent step S123, as in step S105, the focus adjustment process for driving the focus lens 32 to the in-focus position at a predetermined first driving speed is performed. Is done. As described above, even when a moving image is captured, when the processing load of the camera 1 is small and the transmission of the lens information request signal is performed at the first interval, the first driving speed higher than the second driving speed is obtained. The focus lens 32 is driven to the in-focus position at one driving speed.

  In step S124, the camera control unit 21 determines whether or not moving image shooting has ended. For example, when shooting a moving image, the camera control unit 21 determines that the shooting of the moving image has ended when the moving image shooting button provided in the operation unit 28 is pressed by the photographer. Can do. If it is determined that the shooting of the moving image has been completed, the processing of the camera 1 described above is terminated. On the other hand, if it is determined that the shooting of the moving image is continued, the process returns to step S112.

  As described above, in the present embodiment, when a still image is captured, the lens information request signal is transmitted at the first interval. On the other hand, when a moving image is captured, depending on the processing load of the camera 1. Thus, the lens information request signal is transmitted at a second interval having a time interval longer than the first interval. Thereby, in this embodiment, even when the processing load of the camera 1 becomes large for capturing a moving image, the communication load between the lens barrel 3 and the camera body 3 can be reduced. The processing load of the camera 1 when shooting a moving image can be reduced. In particular, in the present embodiment, when shooting a moving image, the moving image looks good, and in order to reduce the driving sound of the focus lens 32, the driving speed of the focus lens 32 is set to a still image. Therefore, even when the lens information request signal is transmitted at the second interval having a time interval longer than the first interval, the focus lens 32 is set to a speed slower than the drive speed of the focus lens 32 at the time of photographing. Lens information can be acquired at appropriate intervals with respect to the driving speed, and the focus lens 32 can be controlled appropriately.

  In the present embodiment, when a shutter release button is half-pressed when a moving image is being shot and the lens information request signal is transmitted at the second interval, the lens information request is sent. In accordance with the signal transmission interval, the focus lens 32 is driven to the in-focus position at a second driving speed that is lower than the first driving speed when the lens information request signal is transmitted at the first interval. As described above, in this embodiment, the lens information is acquired at an appropriate interval according to the driving speed of the focus lens 32 by changing the driving speed of the focus lens 32 according to the transmission interval of the request signal for lens information. The focus lens 32 can be appropriately controlled based on the acquired lens information. On the other hand, for example, when the processing load of the focus lens 32 is high and the lens information request signal is transmitted at the second interval, the focus lens is at the first drive speed that is the maximum drive speed when taking a still image. In the configuration in which the lens 32 is driven to the in-focus position, the lens information acquisition interval becomes too long with respect to the driving speed of the focus lens 32, and thus the focus lens 32 may not be appropriately controlled. For example, when the lens information acquisition interval becomes too long with respect to the driving speed of the focus lens 32, the camera body 2 acquires lens information even when the focus lens 32 stops at the in-focus position. Until it is determined, it is determined that the focus lens 32 is driven, and as a result, the focusing accuracy of the focus lens 32 may be reduced. On the other hand, in the present embodiment, since the lens information can be acquired at an appropriate interval in accordance with the driving speed of the focus lens 32, the focusing accuracy of the focus lens 32 can be improved. In addition, in this embodiment, by changing the driving speed of the focus lens 32 according to the transmission interval of the lens information, the transmission interval of the request information of the lens information becomes too short with respect to the driving speed of the focus lens 32. Since this can be effectively prevented, power saving can be achieved.

  The embodiment described above is described for facilitating 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 lens information request signal is transmitted at the first interval, the focus lens 32 is moved at the first drive speed (for example, the maximum speed among the speeds at which the focus lens 32 can be driven). The configuration of driving at a certain maximum driving speed) is illustrated, but the driving speed of the focus lens 32 when transmitting the lens information request signal at the first interval may be a speed equal to or lower than the first driving speed. It is not limited to the first driving speed. Similarly, in the above-described embodiment, when the lens information request signal is transmitted at the second interval, the focus lens 32 is set to the second drive speed (for example, when the second interval is three times longer than the first interval). Exemplifies a configuration in which the lens information is driven at a second interval, the drive speed of the focus lens 32 when the lens information request signal is transmitted at the second interval is illustrated as a second drive speed. The speed may be any of the following speeds and is not limited to the second driving speed.

  Furthermore, in the above-described embodiment, when a shutter release button is pressed halfway when a moving image is captured, the lens information request signal is transmitted at a second interval longer than the first interval. In this case, the camera control unit 21 of the camera body 2 has a configuration in which the driving speed of the focus lens 32 is set to a second driving speed that is slower than when the lens information request signal is transmitted at the first interval. Although illustrated, it is not limited to this configuration. For example, the lens control unit 37 of the lens barrel 3 has a reception interval of a request signal for lens information from the camera body 2 longer than a predetermined first interval. When it is determined whether the interval is the second interval, and the reception interval of the lens information request signal is determined to be the second interval, the driving speed of the focus lens 32 is determined based on the reception of the lens information request signal. It may set a slow second driving speed than when it is determined to be performed in the first interval.

  In the above-described embodiment, the configuration in which focus detection is performed by the phase difference detection method is illustrated. However, the present invention is not limited to this configuration. For example, a configuration in which focus detection is performed by the contrast detection method may be used. The focus detection may be performed using the contrast detection method, and the focus detection may be performed using the contrast detection method when the focus state cannot be detected using the phase difference detection method. Alternatively, a configuration may be adopted in which focus detection is performed by the phase difference detection method, and focus detection by the phase difference detection method and focus detection by the contrast detection method are performed simultaneously when the focus state cannot be detected by the phase difference detection method.

  Furthermore, in the above-described embodiment, when a still image is taken and a request signal for lens information is transmitted at the first interval, the focus lens 32 is driven to the in-focus position at the first driving speed. However, for example, the focus lens 32 may be driven to the in-focus position at a speed equal to or lower than the first driving speed. Similarly, when a moving image is taken and a request signal for lens information is transmitted at the second interval, the focus lens 32 is moved at the second drive speed when the shutter release button is half-pressed. For example, the focus lens 32 may be driven to the in-focus position at a speed equal to or lower than the second driving speed.

  In the embodiment described above, the imaging element 22 includes the imaging pixel 221 and the focus detection pixels 222a and 222b, and the focus detection pixels 222a and 222b included in the imaging element 22 are configured to perform focus detection by the phase difference detection method. However, the present invention is not limited to this configuration, and a focus detection module for performing focus detection by the phase difference detection method may be provided independently of the image sensor 22.

  The camera 1 according to the present embodiment is not particularly limited, and the present invention may be applied to other optical devices such as a single-lens reflex digital camera, a digital compact camera, a digital video camera, and a camera for a mobile phone. Good.

DESCRIPTION OF SYMBOLS 1 ... Digital camera 2 ... Camera body 21 ... Camera control part 22 ... Imaging device 221 ... Imaging pixel 222a, 222b ... Focus detection pixel 28 ... Operation part 3 ... Lens barrel 32 ... Focus lens 36 ... Focus lens drive motor 37 ... Lens Control unit

Claims (1)

A receiving unit for receiving a request signal for lens information from the camera body;
After the receiving unit receives the lens information request signal, the transmitting unit transmits the lens information to the camera body;
A determination unit that determines whether or not a reception interval of the lens information request signal from the camera body is a second interval longer than a predetermined first interval;
When it is determined that the reception interval of the lens information request signal is the first interval, the focus lens is driven at a speed equal to or lower than a predetermined first speed, and the reception interval of the lens information request signal is An interchangeable lens comprising: a control unit that drives the focus lens at a speed equal to or lower than a second speed that is slower than the first speed when it is determined that the second interval is reached.

Images