JP2007322922A - Imaging system and camera, and lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging system and a camera in each of which drive control of a focus lens in an interchangeable lens can be efficiently performed, and to provide a lens unit. <P>SOLUTION: A camera body 30 has: an imaging device 32 which photographs an object; and a control part 45 which produces a command for controlling a drive of the interchangeable lens 10, and the camera body transmits the command produced by the control part 45 and a synchronization signal for determining a photographing timing of the imaging device 32 to the interchangeable lens 45. The interchangeable lens 10 has: a focus lens 11a which adjusts a focus position of the interchangeable lens 10; a lens control part 15 which moves and stops the focus lens 11a according to the command; and an encoder 13 which detects a position along an optical axis of the focus lens 11a almost with the same timing to a photograph of the imaging device 32 in synchronism with the synchronization signal, positional information of the focus lens 11a detected by the encoder 13 is transmitted to the camera body 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a digital camera, and more particularly to a lens interchangeable digital single-lens reflex camera having an autofocus function.

  Conventionally, TTL (Through The Lens) AF is generally used as an autofocus (AF) mechanism of a single-lens reflex type (hereinafter simply abbreviated as single-lens reflex) of a lens exchange type. In this AF mechanism, a dedicated mechanism for detecting a shift in the focal position is provided in the camera body, and a focus adjustment lens (defocus amount) detected by the mechanism is used to adjust the focus in the interchangeable lens unit (defocus amount). The movement position of the focus lens) is determined.

  On the other hand, compact digital cameras, video cameras, and the like often use so-called imager AF that performs contrast detection using a high-frequency component of a signal from an image sensor. The imager AF repeatedly detects the contrast while moving the focus lens of the lens unit, and determines the focus lens position where the contrast is maximized.

  TTL phase difference AF and imager AF have different characteristics, for example, TTL phase difference AF is focused at higher speed, and imager AF is focused at higher accuracy. ing.

In order to realize high-speed and high-accuracy autofocus, in Patent Document 1 below, a rough adjustment actuator and a fine adjustment actuator for driving the focus lens are installed in the interchangeable lens unit. Describes an autofocus device that achieves high-precision focusing.
JP 2003-241074 A

  However, not only in the device described in Patent Document 1, but in a single-lens reflex camera with interchangeable lenses, the position of the focus lens in the interchangeable lens is set to enable high-precision focusing with the imager AF. It must be detected accurately and transmitted to the camera body at an appropriate timing.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide an imaging system, a camera, and a lens unit that can efficiently perform drive control of a focus lens in an interchangeable lens. .

  That is, the invention described in claim 1 is an imaging system including a camera body and a lens unit that can be attached to and detached from the camera body, and the camera body repeatedly shoots an object imaged by the lens unit. An image sensor, a control unit that generates a command for controlling driving of the lens of the lens unit, the command generated by the control unit, and a synchronization signal that determines a shooting timing of the image sensor are transmitted to the lens unit. A first transmission unit, and the lens unit moves the focus lens along the optical axis according to a command generated by the control unit and a focus lens for adjusting a focal position of the lens unit. Alternatively, the lens control means to be stopped and the timing at which the imaging device takes a picture in synchronization with the synchronization signal Position detection means for detecting a position along the optical axis of the focus lens at substantially the same timing; second transmission means for transmitting position information of the focus lens detected by the position detection means to the camera body; It is characterized by having.

  According to a second aspect of the present invention, in the first aspect of the present invention, the second transmission unit synchronizes position information of the focus lens detected by the position detection unit with the synchronization signal. It transmits to the camera body.

  According to a third aspect of the present invention, in the first aspect of the invention, the lens unit further includes storage means for storing position information of the focus lens detected by the position detection means. The second transmission unit transmits the position information of the focus lens stored in the storage unit.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the second transmission unit receives a predetermined command generated by the control unit transmitted from the first transmission unit. Then, the position information of the focus lens stored in the storage means is transmitted.

  The invention according to claim 5 is the invention according to claim 4, wherein the predetermined command generated by the control means is a command to stop the focus lens.

  According to a sixth aspect of the present invention, there is provided an imaging system comprising a camera body and a lens unit that can be attached to and detached from the camera body, wherein the camera body repeatedly shoots a subject imaged by the lens unit. And a control means for generating a lens movement start command for controlling the driving of the lens of the lens unit, and a trigger for generating a trigger signal in synchronization with the synchronization signal immediately after generation of the lens movement start command generated by the control means And a first transmission means for transmitting the lens movement start command generated by the control means, the trigger signal, and the period information of the synchronization signal to the lens unit, and the lens unit includes the lens In accordance with the focus lens for adjusting the focal position of the unit and the lens movement start command generated by the control means, Lens control means for moving or stopping the focus lens along the optical axis, and the focus lens at the same timing as the timing at which the imaging device takes an image, which is repeated at the same cycle as the synchronization signal starting from the trigger signal And a second transmission means for transmitting the position information of the focus lens detected by the position detection means to the camera body. .

  The invention according to claim 7 is the invention according to claim 6, wherein the lens unit further comprises storage means for storing position information of the focus lens detected by the position detection means. The second transmission unit transmits the position information of the focus lens stored in the storage unit when the predetermined command generated by the control unit transmitted from the first transmission unit is received. Special features.

  According to an eighth aspect of the present invention, in the invention according to any one of the first to seventh aspects, the camera body is configured to focus the lens unit based on image data of a subject photographed by the image sensor. The control unit further includes a calculation unit that calculates a degree of focus representing the degree, and the control unit uses the focus degree calculated by the calculation unit and the position information of the focus lens detected by the position detection unit to determine the focus lens. A signal for controlling the driving of is generated.

  According to a ninth aspect of the present invention, there is provided a camera having a detachable lens unit mounted thereon, the image sensor for repeatedly photographing a subject imaged by the lens unit, and a focus position of the lens unit. Control means for generating a command for controlling the driving of the focus lens; transmission means for transmitting the command generated by the control means and a synchronization signal for determining the photographing timing of the image sensor to the lens unit; Receiving means for receiving position information along the optical axis, and calculating means for calculating a degree of focus representing the degree of focus of the lens unit from image data of a subject photographed by the imaging device, The control means uses the focus degree calculated by the calculation means and the position information of the focus lens detected by the position detection means. And generating a signal for controlling the driving of Kasurenzu.

  According to a tenth aspect of the present invention, in the invention according to the ninth aspect, the receiving means receives position information of the focus lens in synchronization with the synchronization signal.

  The invention described in claim 11 is the invention described in claim 9, further comprising trigger means for generating a trigger signal in synchronization with the synchronization signal immediately after generation of the lens movement start command generated by the control means. The transmission unit transmits the command generated by the control unit, the trigger signal, and the period information of the synchronization signal to the lens unit.

  According to a twelfth aspect of the present invention, there is provided a lens unit that can be attached to a camera body having an image pickup device for repeatedly photographing a subject, a focus lens for adjusting a focal position of the lens unit, Receiving means for receiving a signal; lens control means for moving or stopping the focus lens along an optical axis in accordance with a command for controlling driving of the focus lens received by the receiving means; and the received by the receiving means. Position detection means for detecting a position along the optical axis of the focus lens at substantially the same timing as the time at which the image sensor of the camera captures, and position information of the focus lens detected by the position detection means And transmitting means for transmitting to.

  According to a thirteenth aspect of the present invention, in the invention according to the twelfth aspect, the transmission unit synchronizes position information of the focus lens detected by the position detection unit with a synchronization signal received by the reception unit. And transmitting to the camera body.

  The invention described in claim 14 further comprises storage means for storing position information of the focus lens detected by the position detection means in the invention described in claim 12, wherein the transmission means is the storage means. The position information stored in is transmitted.

  According to a fifteenth aspect of the present invention, in the invention according to the fourteenth aspect, the transmission means receives the focus command stored in the storage means when the reception means receives a predetermined command from the camera body. The lens position information is transmitted to the camera body.

  According to a sixteenth aspect of the present invention, in the fifteenth aspect, the predetermined command received by the receiving means is a command to stop the focus lens.

  According to a seventeenth aspect of the present invention, in the invention according to the twelfth or fourteenth aspect, the receiving means receives a trigger signal and time interval information, and the position detecting means receives the trigger signal. As a starting point, the position along the optical axis of the focus lens is repeatedly detected at the received time interval.

  According to the present invention, a vertical synchronization signal is transmitted from the camera body to the interchangeable lens, and the interchangeable lens transmits a focus lens position when a substantially vertical synchronization pulse is generated to the camera body in synchronization with the vertical synchronization signal. Therefore, since the focus lens position synchronized with the imaging timing of the image sensor can be acquired, even when the interchangeable lens has a control unit such as a lens CPU, high focus adjustment accuracy can be obtained.

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

(First embodiment)
FIG. 1 is a block diagram showing an overall configuration of a single-lens reflex type digital camera showing a first embodiment of the present invention.

  In FIG. 1, this camera includes an interchangeable lens 10 that is a lens unit, and a camera body (camera body) 30 to which the interchangeable lens 10 is attached.

  The interchangeable lens 10 includes an imaging lens system 11 including a focus lens 11a, a lens driving unit 12, an encoder 13, and a lens control unit 15. The focus lens 11a is a lens for performing focus adjustment. The lens driving unit 12 is for adjusting the focus lens 11a in the optical axis direction. The encoder 13 generates a pulse proportional to the moving distance of the focus lens 11a, and detects the position of the focus lens 11a. The lens control unit 15 communicates with the camera body 30 via the lens contact unit 20 and controls the lens driving unit 12. The lens control unit 15 includes a memory 15a as a storage unit. .

  The lens contact portion 20 is a portion where a communication line between a control unit 45 (described later) in the camera body 30 and a lens control unit 15 in the interchangeable lens 10 is coupled. The lens contact portion 20 includes a lens power source supplied from the camera body 30 to the interchangeable lens 10, a plurality of power sources such as a communication clock / data signal and a vertical synchronization signal, and a plurality of contacts to which signals are connected. Yes.

  On the other hand, in the camera body 30, a half mirror 31, an image sensor 32, a phase difference AF sensor unit 34, a first focus detection unit 35, an image processing unit 37, an LCD panel 38, and a finder optical system 39 The second detection unit 41, the control unit 45, a first release switch (1RSW) 47, and a second release switch (2RSW) 48 are included.

  The half mirror 31 divides the imaging light flux incident through the imaging lens system 11 in the interchangeable lens 10 so as to guide it to the imaging element 32 and to the phase difference AF sensor unit 34. With this configuration, the imaging operation and the phase difference AF detection operation can be performed simultaneously.

  The imaging element 32 is a photoelectric conversion element of an imaging optical system for photoelectrically converting the subject image that has passed through the photographing lens system 11, and is configured by a CCD, for example. Details of the phase difference AF sensor unit 34 will be described later.

  The first focus detection unit 35 is for calculating a focus shift amount and the like from the output of the phase difference AF sensor unit 34. The image processing unit 37 processes the output signal of the image sensor 32, extracts image contrast information, and performs white balance, Y processing, color matrix processing, and the like to form a captured image and a viewfinder image. The LCD panel 38 is for an electronic view finder with a built-in backlight, and displays the finder image formed by the image processing unit 37. The finder image is observed by the user through the finder optical system 39.

  The image processing unit 37 also generates a drive control signal for the image sensor 32 based on a reference clock (not shown) transmitted from the control unit 45. For example, a clock signal such as an integration start / end (exposure start / end) timing signal, a light reception signal readout control signal (horizontal synchronization signal, vertical synchronization signal, transfer signal, etc.) of each pixel is generated, and is supplied to the image sensor 32. Output. The vertical synchronization signal VD is also output to the second focus detection unit 41, the control unit 45, and the lens control unit 15.

  The second focus detection unit 41 calculates and outputs an AF evaluation value by judging the history of contrast information obtained from the image processing unit 37. The focus detection area, which is the area for calculating the evaluation value, is determined in advance to coincide with the focus detection area for phase difference detection.

  The control unit 45 is for controlling the entire camera body 30 of the digital camera. The first release switch 47 and the second release switch 48 are two-stage switches that are turned on and off when a release button (not shown) is pressed. When the release button 21 is half-pressed, the first release switch 47 is turned on and a shooting preparation operation is started. When the release button 21 is fully pressed, the second release switch 48 is turned on and the shooting operation is executed. Yes. The captured image is stored in a non-volatile memory (not shown) or the like.

  Next, the imager AF will be described with reference to FIGS.

  FIG. 2 is a block diagram showing a detailed configuration of the second focus detection unit 41, and FIG. 3 is a diagram for explaining the relationship between the focus lens position and the AF evaluation value.

  The second focus detection unit 41 includes a circuit block for obtaining an AF evaluation value. In the second focus detection unit 41, the luminance signal generated in the image processing unit 37 uses a high-pass filter (HPF) 51 for obtaining an AF evaluation value, an A / D converter 52, a focus detection area selection gate 53, The adder 54 is connected so as to be output in order.

  The image processing unit 37 outputs a luminance signal generated from the image signal to the HPF 51 and outputs a synchronization signal to the focus detection area selection gate 53, the adder 54, and the control unit 45 in accordance with the video signal. The HPF 51 extracts a high frequency component contained in the luminance signal. Since the extracted high-frequency component is included in proportion to the image sharpness, the average image sharpness level in the integration range can be quantified by integrating the high-frequency component. The high frequency component that has passed through the HPF 51 is converted into a digital signal by the A / D converter 52 and input to the focus detection area selection gate 53. The focus detection area selection gate 53 is a circuit that extracts only signals corresponding to a plurality of focus detection areas on the imaging screen, and extracts only information related to the subject imaged in the focus detection area.

  The digital signal extracted by the focus detection area selection gate 53 is input to the adder 54 where the digital signals in the focus detection area for one field are integrated. The value accumulated by the adder 54 is input to the control unit 45 as an AF evaluation value indicating the sharpness of the image.

  The controller 45 can perform a known hill-climbing autofocus (hereinafter referred to as imager AF) using this AF evaluation value. When the imager AF is performed, the control unit 45 drives the focus lens 11a via the lens control unit 15 and acquires the focus lens position information, and simultaneously inputs the AF evaluation value from the adder 54. AF evaluation coordinate values ((P1, H1) (P2, H2) (P3, H3)) shown in FIG. Then, the peak position at which the AF evaluation value is maximized is calculated from the AF evaluation coordinate values by storage calculation or the like, and the focus lens 11a is moved to the focus target position PM at which the obtained evaluation value is at the peak.

  Further, it is possible to adopt a focus detection area selected from a plurality of focus detection areas based on a predetermined selection algorithm (for example, closest selection), or to adopt a focus detection area selected by a photographer. Also good.

  Next, the phase difference AF will be described with reference to FIGS.

  FIG. 4 is a diagram showing a detailed configuration of the phase difference AF sensor unit 34, FIG. 5 is an explanatory diagram for obtaining a deviation amount of the photographing lens related to two subject images, and FIG. 6 is a phase difference detection in the present embodiment. FIG. 7 is a block diagram showing the configuration of the portion related to the above, and FIG. 7 is a diagram showing the relationship between the phase difference amount and the correlation function.

  As shown in FIG. 4, the basic components of the phase difference AF sensor unit 34 are a field mask 61 and a condenser lens 62 arranged in the vicinity of a planned imaging plane on which a subject image is formed by the photographing lens system 11. On the rear side, porous aperture masks 63a and 63b, secondary optical systems 64a and 64b having a secondary imaging lens, and a plurality of photoelectric conversion element arrays 65a and 65b are arranged behind them. With this configuration, two subject images formed by light beams that have passed through two different pupil regions 68a and 68b of the photographing lens system 11 are re-imaged on different photoelectric conversion element arrays 65a and 65b, respectively. Focus detection is performed by utilizing the fact that the relative positional relationship between the images changes depending on the in-focus state of the taking lens system 11. The phase difference that is the relative positional relationship between the two subject images described above can be obtained by obtaining the correlation.

  Now, as shown in FIG. 5 (a), the area of the region where the two subject images (A and B images) do not overlap (the sum of the absolute values of the differences between the corresponding pixels of the A and B images) is expressed as S. And Then, as shown in FIG. 5B, one image (A image in this example) is shifted by one pixel (1 bit) of the photoelectric conversion element, and the minimum value is obtained. As a result, as shown in FIG. 5C, if the A image and the B image coincide with each other, the minimum value inevitably becomes the minimum value. Therefore, the shift amount that causes the minimum value is the relative deviation amount between the A image and the B image. The phase difference is

  In these focus detection devices, the center-of-gravity interval between the two pupil regions 68a and 68b becomes the baseline length in triangulation, and the defocus amount of the photographing lens is based on the phase difference that is the relative shift amount on the photoelectric conversion element. Can be requested.

  FIG. 6 is a configuration diagram showing a portion related to phase difference detection of the present embodiment. In FIG. 6, photoelectric conversion element arrays 65 a and 65 b are the same as those shown in FIG. 4 and are included in the phase difference AF sensor unit 34. On the other hand, the first focus detection unit 35 includes an A / D converter 71 and an arithmetic processing unit 72.

  The analog output from each pixel in the photoelectric conversion element arrays 65a and 65b is converted into a digital signal by the A / D converter 71. Further, as described above, the arithmetic processing unit 72 is built in the first focus detection unit 35. The arithmetic processing unit 72 obtains the phase difference between the two images and outputs the phase difference to the control unit 45. In the control unit 45, the imaging lens system 11 is controlled by this phase difference.

  Now, the output values of the photoelectric conversion element arrays 65a and 65b A / D converted by the A / D converter 71 are respectively expressed as L (1), L (2),..., L (n), R ( 1), R (2),..., R (n). Then, the correlation function F (i) indicating the degree of coincidence of images with respect to the relative shift amount (phase difference) of two images of phase difference = i · p (p is a pixel pitch) is, for example, the following equation (1). Given.

  Here, m is the number of pixels for which the correlation is calculated, and m <n. If the two images on the photoelectric conversion element rows 65a and 65b are relatively shifted by k pixel pitches, F (k) = 0. However, since the image signals from the two photoelectric conversion element arrays 65a and 65b are unlikely to be completely the same due to the influence of pixel noise or the like, usually F (k)> 0.

  FIG. 7 is a diagram showing an example of the relationship between the phase difference amount i and the correlation function F (i). As described above, (i, F (i)) is discrete data, but is shown as a continuous graph for convenience. After a minimum value of F (i) is obtained in a predetermined range of i, an interpolation calculation is performed using correlation function values before and after the minimum value in order to perform highly accurate detection.

  Since the focus lens 11a is driven on the basis of the defocus amount thus determined, high-speed focusing is possible even in a wide range of defocus states.

  Next, the operation of the digital camera configured as described above will be described with reference to the flowcharts of FIGS. Note that the processing operations according to these flowcharts are mainly performed in accordance with commands from the control unit 45.

  FIG. 8 is a flowchart for explaining the operation of the main routine of the digital camera in this embodiment. When the power is turned on (turned on) by a power switch (not shown) provided in the camera body 30, first, in step S1, initial lens communication is performed. This is communicated between the control unit 45 in the camera body 30 and the lens control unit 15 in the interchangeable lens 10 to initialize the interchangeable lens 10 and to be stored in the interchangeable lens 10. The various data are read out and stored in a storage unit (not shown) included in the control unit 45. The data in the interchangeable lens 10 includes various correction values related to AF and the like.

  Next, in step S2, the state of the first release switch (1RSW) 47 is determined by half-pressing the release button (not shown) described above. Here, the process waits until the first release switch 47 is turned on and a preparation for photographing is instructed.

  Here, when the first release switch 47 is turned on, the routine proceeds to step S3, where phase difference detection is executed. Here, a signal is acquired from the phase difference AF sensor unit 34, and the amount of defocus is calculated by the first focus detection unit 35. Also, it is evaluated whether or not phase difference detection is possible, and the high reliability of detection is calculated. Next, in step S4, it is determined whether or not a defocus amount with high reliability has been obtained in the phase difference detection, that is, whether or not it can be detected. As a result, if it is detectable, the process proceeds to step S5, and if not detectable, the process proceeds to step S9.

  In step S5, it is determined whether or not the detected defocus amount is within a predetermined range. The predetermined range is a numerical value determined in advance so that the focusing operation is performed with sufficiently high accuracy and high speed by the imager AF within this range. In step S5, if it is within the predetermined range, the process proceeds to step S8, the in-range flag is set, and then the process proceeds to step S9. On the other hand, if it is not within the predetermined range, the process proceeds to step S6.

  In step S6, the driving amount of the focus lens 11a for obtaining the in-focus state is calculated from the obtained defocus amount. Next, in step S7, lens driving is performed. That is, the calculated lens moving amount is transmitted to the lens control unit 15 in the interchangeable lens 10, and the lens control unit 15 controls the lens driving unit 12 to drive the focus lens 11a. Then, the process proceeds to step S3, where phase difference detection is performed.

  In step S9, the operation of the subroutine “imager AF” is executed. Details of the processing operation of this subroutine “imager AF” will be described later.

  Next, in step S10, it is determined by referring to a flag or the like whether or not an in-focus state is obtained as a result of the imager AF operation. If the in-focus state is obtained, the process proceeds to step S11. If the in-focus state cannot be obtained, the process proceeds to step S14.

  In step S <b> 11, a focus display indicating that the focus is achieved is displayed on the LCD panel 38. In step S14, a display indicating out-of-focus is displayed on the LCD panel 38. Thereafter, the process proceeds to step S15, and after the first release switch 47 is reset to OFF, the process proceeds to step S2.

  In step S12, the process waits until a second release switch (2RSW) 48 by turning on a release button (not shown) is turned on. Then, when the second release switch 48 is turned on, the process proceeds to step S13, and photographing by the winning image sequence is performed. After the photographing is completed, the first release switch 47 is reset to OFF in step S15, and the process proceeds to step S2.

  The first release switch 47 is configured so that it can be turned off electrically even if the contacts are in mechanical contact.

  As described above, the rough adjustment of the focus adjustment is basically performed by the phase difference AF, and the fine adjustment of the focus adjustment is performed by the imager AF.

  FIG. 9 is a flowchart for explaining the focus detection operation by the processing operation of the subroutine “imager AF” in step S9 of the flowchart of FIG.

  When the present subroutine is entered, first, at step S21, it is determined whether or not the above-described in-range flag is set. If the in-range flag is set, the process proceeds to step S22, and if not set, the process proceeds to step S23.

  In step S22, the scan range of the imager AF is set. This scan range is set to ΔX before and after the current position of the focus lens 11a as the center position. Here, ΔX is a predetermined scanning range assuming that the focusing operation is performed with sufficiently high accuracy and high speed by the imager AF, and is stored in the memory 15a in the interchangeable lens 10 and read out. Used. ΔX is appropriately changed according to parameters such as the focal length of the interchangeable lens 10, the position (distance) of the focus lens 11a, and the reliability of phase difference detection.

  On the other hand, in step S23, the scan range is set to the entire focus lens movable range, that is, from the closest distance to infinity. This is because a reliable phase difference could not be detected or the phase difference AF has not been executed in advance, so there is a high possibility that the phase difference is not located near the focus. The scan range is transmitted to the lens control unit 15 via the lens contact unit 20 by lens communication, and the operation control of the actual scan range is performed by the lens control unit 15. Thereafter, the process proceeds to step S24.

  In step S24, a predetermined command is transmitted to the lens control unit 15, the lens driving unit 12 is controlled via the lens control unit 15 to the side closer to the end of the scan range from the current lens position, and the focus lens 11a is moved. Moved. Next, in step S25, a lens driving command is transmitted to the lens control unit 15, and the scanning operation of the focus lens 11a is started. Further, in step S26, exposure (EXP) and image data reading (READ) are executed at a predetermined timing from the time when the vertical synchronizing signal VD is generated in the image processing unit 37, and based on the read image data. Thus, the AF evaluation value of the imager AF is calculated.

  In step S27, the rise of the vertical synchronizing signal VD is waited. When the rise of VD is input here, the process proceeds to step S28 and the focus lens position transmitted from the lens control unit 15 is received. Next, in step S29, the AF evaluation value acquired in step S26 and the lens position of the focus lens 11a acquired in step S28 are stored as an AF evaluation value history.

  Here, the relationship between the position of the focus lens 11a and the AF evaluation value will be described with reference to the characteristic diagram of FIG.

  In step S30, the evaluation value history is referred to and it is determined whether or not the focal point (peak value of the evaluation value) has been passed. Here, if the peak has passed, the process proceeds to step S32, and if not, the process proceeds to step S31. In step S31, it is determined whether or not the entire scan range set in step S22 or S23 has been scanned. If the scan is completed, the process proceeds to step S35, and if the area to be scanned remains, the process proceeds to step S26.

  In the loop of steps S26 to S31 described above, the focus lens 11a continues to move, and the peak search of the imager AF is performed by repeating the above processing operation.

  On the other hand, in step S32, since it is determined that the peak of the evaluation value has been exceeded, a command that causes the lens control unit 15 to stop the lens by communication between the camera body 30 and the interchangeable lens 10 (hereinafter referred to as body / lens communication). Sent to stop the lens. Next, in step S33, the lens position that is the peak position is obtained in detail from the evaluation value history by interpolation processing. Based on this position, the focus lens 11a is moved by the lens driving unit 12 via the lens control unit 15 by body / lens communication.

  Further, in step S34, after the peak evaluation value as a result of the imager AF is stored, the process exits from this subroutine and returns to the main routine of FIG.

  On the other hand, when the process in the scan range is completed in step S31 without obtaining the focal point (peak value) in step S30, the process proceeds to step S35. In step S35, the focus lens 11a is moved to the initial position of the scan range. In step S36, the fact that the imager AF cannot be detected is stored in a flag or the like, and the process ends. Thereafter, the process returns to the main routine of FIG.

  Next, the operation of the interchangeable lens 10 will be described with reference to the flowchart of FIG.

  When this routine is entered and a power switch (not shown) in the camera body 30 is turned on, lens power is supplied to the interchangeable lens 10 from the camera body 30 side via the lens contact 20. Thus, when the lens power is supplied to the interchangeable lens 10, each part in the interchangeable lens 10 is initialized and the lens control unit 15 becomes operable. In step S41, the body communication request from the control unit 45 is awaited. It becomes. When a body communication request from the control unit 45 is generated in step S41, the process proceeds to step S42.

  In step S42, body / lens communication is performed, and a command transmitted from the control unit 45 is received. Next, in step S43, a lens drive command is determined. If it is a lens drive command, the process proceeds to step S45, and if it is any other command, the process proceeds to step S44, and an operation corresponding to the command is executed.

  For example, in the lens information request command received first after the lens power is turned on, various data stored in the interchangeable lens 10 are read and transmitted to the control unit 45. The control unit 45 stores the received data in its own storage unit (not shown). The data in the interchangeable lens 10 includes various correction values related to AF. After the processing operation in step S44 is executed, the process proceeds to step S41.

  Step S25 (lens movement start) when the routine of the imager AF shown in FIG. 9 is executed is executed by receiving the lens driving command in step S45.

  When the lens driving is started in step S45, the falling of the signal VDP synchronized with the vertical synchronizing signal output from the control unit 45 to the lens control unit 15 through the lens contact 20 is detected in the subsequent step S46. Wait until Here, when the fall of VDP is detected, the process proceeds to step S47, and output data of the encoder 13 indicating the lens position is acquired.

  In step S48, the process waits until the rise of the VDP is detected. Here, when the rise of the VDP is detected, the process proceeds to step S49, and the lens position acquired in step S47 is transmitted to the control unit 45. In step S50, it is determined whether a lens stop command has been received. If a lens stop command is received, the process proceeds to step S51 and the lens is stopped. On the other hand, if the lens stop command is not received in step S50, the process proceeds to step S46 and enters a state of waiting for the VDP to fall. Thereafter, the same operation as described above is repeated until a lens stop command is received.

  FIG. 11 is a timing chart for explaining the operation of the imager AF.

  The operation of the imager AF will be described below with reference to the timing chart of FIG. 11 and the flowchart described above.

  First, when the imager AF is started by the control unit 45 (step S9 in the flowchart of FIG. 8), lens movement start processing is performed, and a lens drive command is transmitted from the control unit 45 to the lens control unit 15. (Step S25 in the flowchart of FIG. 9). The lens control unit 15 receives the lens driving command, starts lens driving, and drives the focus lens 11a of the interchangeable lens 10 (step S45 in the flowchart of FIG. 10).

  The encoder 13 generates an encoder signal as the focus lens 11a moves. The lens control unit 15 can acquire the focus lens position by counting the signal pulses of the encoder signal.

  In the timing chart of FIG. 11, the focus lens 11a is continuously driven. In the camera body 30, the imaging operation of the imaging element 32 is performed in accordance with a predetermined timing of the vertical synchronization signal VD generated by the image processing unit 37. When exposure (EXP) of the image sensor 32 is performed and exposure is completed, image data of the image sensor 32 is read (READ) by the image processing unit 37. In parallel with this reading operation, the image processing unit 37 performs AF evaluation value detection (IAF) (step S26 in the flowchart of FIG. 9). Note that the end timing of calculation of the AF evaluation value is set in advance so as to end before the rise of the vertical synchronization signal VD.

  The lens control unit 15 waits for the fall of the lens contact signal VDP (step S46 in the flowchart of FIG. 10). When the falling edge of VDP is input, the lens control unit 15 acquires focus lens position data from the pulse count output of the encoder 13 (step S47 in the flowchart of FIG. 10).

  Thereafter, the lens contact signal VDP (vertical synchronization signal VD) is waited for to rise (step S48 in the flowchart of FIG. 10). When the rise of VDP is input (step S49 in the flowchart of FIG. 10), the acquired focus lens The position data is transmitted from the lens control unit 15 to the control unit 45. The control unit 45 waits for the rise of the vertical synchronization signal VD (step S27 in the flowchart of FIG. 9). When the rise of VD is input (step S28 in the flowchart of FIG. 9), the lens transmitted from the lens control unit 15 is transmitted. The position is received (step S29 in the flowchart of FIG. 9).

  As described above, the focus lens position information is communicated in synchronization with the rise of the vertical synchronization signal VD, and the control unit 45 can acquire the focus lens position information at the fall of the vertical synchronization signal VD. The above operation is repeatedly executed while the focus lens is driven during the imager AF operation. When the lens stop command is transmitted from the control unit 45 to the lens control unit 15 by body / lens communication, the drive of the focus lens 11a is stopped (step S51 in the flowchart of FIG. 10).

  As described above, the camera body 30 transmits a vertical synchronization signal that governs the operation timing of the image sensor 32 to the interchangeable lens 10, and the interchangeable lens 10 acquires the focus lens position at the time of generation of a pulse synchronized with the vertical synchronization signal. Can be transmitted to the camera body 30. Therefore, since the focus lens position synchronized with the imaging timing of the image sensor 32 can be acquired, even when the interchangeable lens 10 has the lens CPU, higher focus adjustment accuracy than the imager AF can be obtained. Further, by combining phase difference AF and imager AF, high-speed and high-precision AF can be realized.

  In addition, since the acquisition timing of the focus lens position acquired in synchronization with the true shooting timing (FIG. 11: EXP) and the vertical synchronization signal has a certain time difference, the focus lens position information is corrected in consideration of the moving speed of the focus lens. May be.

(Second Embodiment)
In the first embodiment described above, the lens position is communicated between the control unit 45 and the lens control unit 15 for each vertical synchronization signal VD, but the VD cycle is generally as short as about 33 ms. It's time. In parallel with other camera internal processes, executing the communication process within the time of this VD cycle increases the load on both hardware and software.

  To improve these points is the gist of the second embodiment of the present invention.

  In the second embodiment, the lens control unit 15 acquires lens position data for each vertical synchronization signal VD, but body / lens communication of lens position data is not executed. After the peak is detected by executing the imager AF, all lens position data acquired corresponding to the AF evaluation value is transmitted to the control unit 45 by body / lens communication all at once.

  Note that the configuration and basic operation of the camera in the second embodiment are the same as the configuration and operation of the camera of the first embodiment shown in FIGS. Are denoted by the same reference numerals, illustration and description thereof are omitted, and only different portions will be described.

  FIG. 12 illustrates the operation of the second embodiment, and the operation flowchart of the control unit 45 for explaining the focus detection operation by the “imager AF operation” performed in step S9 in the flowchart of FIG. It is.

  In the flowchart of FIG. 12, steps S61 to S64 and steps S74 to S75 are the same as steps S21 to S24 and steps S35 to S36 of the flowchart of FIG. The description thereof is omitted.

  In step S65, a lens driving command is transmitted to the lens control unit 15, and the scanning operation of the focus lens 11a is started. Next, in step S66, the image processor 37 performs exposure (EXP) and image data read (READ) at a predetermined timing from the time when the vertical synchronization signal VD is generated, and an imager based on the read image data. An AF evaluation value of AF is calculated. In step S67, the AF evaluation value calculated in step S66 is stored as an AF evaluation value history.

  Next, in step S68, the evaluation value history stored in step S67 is referred to and it is confirmed whether or not the focal point (peak value of the evaluation value) has been passed. Here, if it has not passed the peak value, the process proceeds to step S69, and if it has passed, the process proceeds to step S70. In step S69, it is determined whether or not all the set scan range has been scanned. If the scan has been completed, the process proceeds to step S74. If the area to be scanned remains, the process proceeds to step S66. In the loop of steps S66 to S69, the focus lens 11a continues to move, and the peak search of the imager AF is performed by repeating the above process.

  In step S70, since it is determined that the peak has been exceeded in step S68, a lens stop command is transmitted to the lens control unit 15 by body / lens communication, and the lens is stopped. In subsequent step S71, all lens position data acquired in correspondence with the AF evaluation value is collectively received by body lens communication. Further, in step S72, the lens position that is the true peak position is obtained in detail from the AF evaluation value history corresponding to the focus lens position acquired in step S71 by interpolation processing, and through body lens communication. The focus lens 11 a is driven by the lens driving unit 12 via the lens control unit 15. In step S73, the peak evaluation value that is the result of the imager AF is stored. Thereafter, the process returns to the main routine shown in FIG.

  FIG. 13 is a flowchart for explaining the operation of the second embodiment and for explaining the operation of the lens control unit 15. In the flowchart of FIG. 13, steps S81 to S83 are the same as steps S41 to S43 of the flowchart of FIG. 10 described above, and thus corresponding step numbers are given and description thereof is omitted.

  In the imager AF, the lens movement start operation in step S65 in the flowchart of FIG. 12 is executed when a lens drive command is received in step S87. Next, in step S88, the process waits until VDP falls. When the fall of the VDP is detected, the process proceeds to step S89, where the lens position encoder data is received and acquired and stored in the memory 15a in the lens control unit 15.

  In step S90, it is determined whether a lens stop command has been received. If the lens stop command is received, the process proceeds to step S91 and the lens is stopped. Thereafter, the process proceeds to step S81 and waits for a body communication request. On the other hand, if the lens stop command is not received in step S90, the process proceeds to step S88 to wait for the VDP to fall, and thereafter, the same operation as above is repeated until the lens stop command is received. It is.

  In step S83, when a lens position transmission command is transmitted from the control unit 45, the process proceeds to step S84 to determine whether or not a lens position transmission command is received. If the transmission command is received, the process proceeds to step S85, and all lens position data acquired in synchronization with the fall of the vertical synchronization signal VDP is transmitted to the control unit 45. Thereafter, the process proceeds to step S81 and waits for a body communication request.

  Furthermore, when the lens position transmission command is not received in step S84, the process proceeds to step S86. In step S86, after another command determination process is performed, the process proceeds to step S81 and waits for a body communication request.

  FIG. 14 is a timing chart for explaining the operation of the second embodiment and for explaining the operation of the imager AF.

  Hereinafter, the operation of the imager AF will be described with reference to the timing chart of FIG. 14 and the flowchart described above.

  In step S9 of the flowchart of FIG. 8, when the imager AF is started by the control unit 45 (step S9 of the flowchart of FIG. 8), lens movement start processing is performed, and the control unit A lens drive command is transmitted from 45 (step S25 in the flowchart of FIG. 9). The lens control unit 15 receives the lens driving command, starts lens driving, and drives the focus lens 11a of the interchangeable lens 10 (step S87 in the flowchart of FIG. 13).

  The encoder 13 generates an encoder signal as the focus lens 11a moves, and the lens control unit 15 counts this signal pulse, whereby the focus lens position can be acquired.

  In the timing chart of FIG. 14, the focus lens 11a is continuously driven. In the camera body 30, the imaging operation of the imaging element 32 is performed in accordance with a predetermined timing of the vertical synchronization signal VD generated by the image processing unit 37. When exposure (EXP) of the image sensor 32 is performed and exposure is completed, image data of the image sensor 32 is read (READ) by the image processing unit 37. In parallel with this reading operation, the image processing unit 37 calculates an AF evaluation value (IAF) (step S26 in the flowchart of FIG. 9).

  Note that the end timing of the calculation of the AF evaluation value is set in advance so as to end before the fall of the vertical synchronization signal VD. The lens control unit 15 waits for the fall of the lens contact signal VDP (vertical synchronization signal VD) (step S88 in the flowchart of FIG. 13), and when the fall of VDP is detected, the count of output pulses of the encoder 13 The lens position is acquired and stored in the memory 15a (step S89 in the flowchart of FIG. 13).

  The above operation is repeatedly executed in synchronization with the timing of the vertical synchronization signal VD during driving of the focus lens during the imager AF operation. When a lens stop command is transmitted from the control unit 45 to the lens control unit 15 through body / lens communication, the drive of the focus lens 11a is stopped (step S91 in the flowchart of FIG. 13).

  Further, when a lens position data transmission command is transmitted from the control unit 45 to the lens control unit 15, the four focus lens position data acquired and stored corresponding to the AF evaluation value is transmitted from the lens control unit 15. It is transmitted to the controller 45 (step S85 in the flowchart of FIG. 13).

  As described above, the camera body 30 transmits a vertical synchronization signal that controls the operation timing of the image sensor 32 to the interchangeable lens 10, and the interchangeable lens 10 acquires the position of the focus lens being driven in synchronization with the vertical synchronization signal. The focus lens position data is transmitted to the camera body after the peak search sequence of the imager AF is completed.

  Therefore, according to the second embodiment, the focus lens position synchronized with the imaging timing of the image sensor can be acquired. Therefore, even when the interchangeable lens has a lens CPU, the focus adjustment is higher than that of the imager AF. Accuracy can be obtained. Further, since the focus lens position is not communicated during the peak search of the imager AF, the communication processing load of the control unit 45 and the lens control unit 15 can be reduced, and the cost can be reduced by simplifying the circuit and during the peak search. In addition to processing in parallel, it is possible to prevent performance degradation of specifications.

(Third embodiment)
In the first and second embodiments described above, the vertical synchronization signal VD is exchanged between the camera body 30 and the interchangeable lens 10 via the lens contact. However, since the number of contact points and the installable area are limited, it is necessary to reduce the number of signals as much as possible. Therefore, in the third embodiment, such a point is further improved.

  That is, in the third embodiment, the period of the vertical synchronization signal VD is transmitted in advance from the control unit 45 in the camera body 30 to the lens control unit 15 in the interchangeable lens 10 and is stored in the memory 15 a in the lens control unit 15. . Then, at the start of the imager AF, a signal synchronized with the vertical synchronization signal VD is transmitted only once (trigger).

  Upon receiving this trigger, the lens control unit 15 acquires the focus lens position in synchronization with the period of the vertical synchronization signal VD stored by an internal counter (not shown), and the control unit 45 from the lens control unit 15. Send to. The trigger signal also serves as a signal line for a serial communication line. For example, when there are four serial communication lines: clock, data, request, and acknowledge signal, they are superimposed on the request or acknowledge signal.

  Hereinafter, a third embodiment of the present invention will be described.

  FIG. 15 is a block diagram showing an overall configuration of a single-lens reflex digital camera showing a third embodiment of the present invention.

  The configuration and basic operation of the camera in the third embodiment are the same as the configuration and operation of the camera in the first and second embodiments shown in FIGS. The same reference numerals are assigned to the same parts, illustration and description thereof are omitted, and only different parts will be described.

  15 is different from the camera of FIG. 1 in that a timer 17 for generating a pulse having a constant period is added in the interchangeable lens 10 and there is no vertical synchronizing signal VDP as a signal of the lens contact portion 20. .

  Next, the operation of the lens control unit 15 in the third embodiment of the present invention will be described with reference to the flowchart of FIG.

  FIG. 16 is a flowchart for explaining the operation of the lens control unit 5.

  In the flowchart of FIG. 16, steps S101 to S103 and step S104 are the same as steps S41 to S3 and step S44 of the flowchart of FIG. 10 described above. Omitted.

  In the imager AF, the operation of step S25 in the flowchart of FIG. 9 proceeds to step S105 when a lens drive command is received from the control unit 45 by the lens control unit 15 in step S103 of the flowchart of FIG. And executed. In the next step S106, the control waits for the fall of the trigger signal synchronized with the vertical synchronizing signal of the lens contact 20. When the falling edge of the trigger signal is detected, the process proceeds to step S107, and the position of the focus lens 11a is acquired based on the count value of the output pulse from the encoder 13.

  Next, in step S108, an internal counter (not shown) of the lens control unit 15 is reset, and counting of output pulses of the timer 17 is started. Subsequently, in step S109, the lens position acquired in step S106 is transmitted to the control unit 45.

  In step S110, it is determined whether or not the output pulses of the timer 17 have been counted by the number corresponding to the period TVD of the vertical synchronization signal VD stored in the lens control unit 15 in advance. The period TVD is transmitted from the control unit 45 to the lens control unit 15 at the time of initial body / lens communication, and stored in the memory 15 a of the lens control unit 15.

  When the counting is completed in step S110, it is determined in step S111 whether a lens stop command from the control unit 45 has been received. If no lens stop command has been received, the process proceeds to step S107, and the position of the focus lens 11a is acquired. In this way, the loop of steps S107 to S111 is repeated, and the lens position is acquired and controlled by the timer 17 and the internal counter of the lens control unit 15 at the same period as the TVD, that is, in synchronization with the vertical synchronization signal. Transmitted to the unit 45.

  On the other hand, if a lens stop command is received in step S111, the process proceeds to step S112 to stop the lens. Thereafter, the process proceeds to step S101, and the camera body 30 waits for a communication request.

  FIG. 17 is a timing chart for explaining the operation of the third embodiment and for explaining the operation of the imager AF.

  Hereinafter, the operation of the imager AF will be described with reference to the timing chart of FIG. 17 and the above-described flowchart.

  First, when the imager AF is started by the control unit 45 (step S9 in the flowchart of FIG. 8), lens movement start processing is performed, and a lens drive command is transmitted from the control unit 45 to the lens control unit 15. (Step S25 in the flowchart of FIG. 9). The lens control unit 15 receives the lens driving command, starts lens driving, and drives the focus lens 11a of the interchangeable lens 10 (step S105 in the flowchart of FIG. 16).

  The encoder 13 generates a pulse signal as the focus lens 11a moves. The lens control unit 15 can detect the focus lens position by counting the pulses.

  In the timing chart of FIG. 17, the focus lens 11a is continuously driven. In the camera body 30, the imaging operation of the imaging element 32 is performed in accordance with a predetermined timing of the vertical synchronization signal VD generated by the image processing unit 37. When exposure (EXP) of the image sensor 32 is performed and exposure is completed, image data of the image sensor 32 is read (READ) by the image processing unit 37. In parallel with this reading operation, the image processing unit 37 calculates an AF evaluation value (IAF) (step S26 in the flowchart of FIG. 9). Note that the end timing of calculation of the AF evaluation value is set in advance so as to end before the rise of the vertical synchronization signal VD.

  The lens control unit 15 waits for the fall of the lens contact signal trigger (a signal synchronized with the vertical synchronization signal VD) (step S106 in the flowchart of FIG. 16). When the fall is detected, the position of the focus lens 11a is acquired from the count value of the output pulse of the encoder 13 (step S107 in the flowchart of FIG. 16).

  At the same time, counting of an internal counter (not shown) of the lens control unit 15 is started (108 in the flowchart of FIG. 16). Then, when counting is performed until the same time as the vertical synchronizing signal cycle TVD stored in the lens control unit 15 has passed (step S109 in the flowchart of FIG. 16), the position of the focus lens 11a is acquired and the control unit The acquired lens position data is transmitted to 45 (step S110 in the flowchart of FIG. 16).

  The above operation is repeatedly executed in synchronization with the end of the TVD count of the internal counter of the lens control unit 15 during driving of the focus lens during the imager AF operation. When a lens stop command is transmitted from the control unit 45 to the lens control unit 15 through body / lens communication, the drive of the focus lens 11a is stopped (step S112 in the flowchart of FIG. 16).

  As described above, in the third embodiment, the period information of the vertical synchronization signal that governs the operation timing of the image sensor 32 is transmitted from the camera body 30 to the interchangeable lens 10 in advance. Then, a trigger signal synchronized with the first vertical synchronization signal after the start of the imager AF is transmitted to the interchangeable lens 10, and the interchangeable lens 10 is being driven in synchronization with the period of the vertical synchronization signal by time measurement from the trigger signal. The focus lens position is acquired.

  Therefore, since the focus lens position synchronized with the imaging timing of the image sensor 32 can be acquired, even when the lens CPU is included in the interchangeable lens, higher focus adjustment accuracy than the imager AF can be obtained.

  Further, since the lens contacts are used only for the first trigger signal, the number of lens contacts can be reduced, and the cost can be reduced and the performance of multifunction can be improved.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  The fourth embodiment is different from the third embodiment described above in the following points.

  That is, after the peak search of the imager AF, the stored all focus lens position data is transmitted from the lens control unit 15 to the control unit 45.

  At the start of the imager AF, a signal synchronized with the vertical synchronization signal VD is transmitted only once (trigger). In response to this trigger, the lens control unit 15 acquires and stores the focus lens position in synchronization with the period of the vertical synchronization signal VD stored by an internal counter (not shown).

  In addition, for each vertical synchronization signal VD, the communication processing of the focus lens position is executed in parallel with the other internal processing of the camera, because both the hardware and the software are electrically very heavy, which increases the cost and performance. There are adverse effects such as decline.

  The gist of the fourth embodiment is to improve these points.

  The fourth embodiment of the present invention will be described below.

  The configuration of the camera in the fourth embodiment is the same as that of the camera of the third embodiment shown in FIG. 15, and the basic operation is shown in FIGS. Since the operations are the same as those in the first to third embodiments, the same portions are denoted by the same reference numerals, illustration and description thereof are omitted, and only different portions will be described.

  FIG. 18 is a flowchart for explaining the operation of the lens control unit 15 in the fourth embodiment of the present invention.

  In the flowchart of FIG. 18, steps S121 to S123 and step S124 are the same as steps S101 to S103 and step S105 of the flowchart of FIG. 16 described above. Omitted.

  In the imager AF, the operation of step S25 in the flowchart of FIG. 9 proceeds to step S124 when the lens drive command is received from the control unit 45 by the lens control unit 15 in step S123 of the flowchart of FIG. And executed. In subsequent step S125, the control waits for the fall of the trigger signal synchronized with the vertical synchronizing signal of the lens contact 20. When the falling edge of the trigger signal is detected, the process proceeds to step S126, and the position of the focus lens 11a is acquired based on the count value of the output pulse from the encoder 13. It is stored in the memory 15 a of the lens control unit 15.

  In step S127, counting of an internal counter (not shown) of the lens control unit 15 is started. Next, in step S128, it is determined whether the output pulses of the timer 17 have been counted by the number corresponding to the period TVD of the vertical synchronization signal VD stored in the lens control unit 15 in advance. The period TVD is transmitted from the control unit 45 to the lens control unit 15 and stored in the control unit 45 at the time of initial lens communication.

  When the counting ends in step S128, the process proceeds to step S129, and it is determined whether a lens stop command from the control unit 45 has been received. If no lens stop command is received, the process proceeds to step S127, where the position of the focus lens 11a is acquired and stored in the memory 15a in the lens control unit 15. As described above, the loop of steps S126 to S129 is repeated and the output pulses of the timer 17 are counted, so that the lens position is acquired at the same period as TVD, that is, in synchronization with the vertical synchronization signal VD. Remembered.

  On the other hand, if a lens stop command is received in step S129, the process proceeds to step S130 and the lens is stopped. Thereafter, the process proceeds to step S121 and waits for a body communication request.

  If the lens drive command is not received in step S123, the process proceeds to step S131 to determine whether or not a lens position transmission command is received. As a result, when a lens position transmission command is received from the control unit 45, the process proceeds to step S132, and the acquired all lens position data is transmitted to the control unit 45. Thereafter, the process proceeds to step S121.

  On the other hand, if the lens position transmission command is not received in step S131, the process proceeds to step S133, and after other command determination processing is performed, the process proceeds to step S121.

  FIG. 19 is a timing chart for explaining the operation of the fourth embodiment and for explaining the operation of the imager AF.

  Hereinafter, the operation of the imager AF will be described with reference to the timing chart of FIG. 19 and the flowchart described above.

  First, when the imager AF is started by the control unit 45 (step S9 in the flowchart in FIG. 8), a lens drive command is transmitted from the control unit 45 to the lens control unit 15 (step S65 in the flowchart in FIG. 12). ). The lens control unit 15 receives the lens driving command, starts lens driving, and drives the focus lens 11a of the interchangeable lens 10 (step S124 in the flowchart of FIG. 18). The encoder 13 generates a pulse signal as the focus lens 11a moves. The lens control unit 15 can detect the focus lens position by counting the pulses.

  In the timing chart of FIG. 19, the focus lens 11a is continuously driven. In the camera body 30, the image pickup operation of the image pickup device 32 is performed at a predetermined timing of the vertical synchronization signal VD generated by the image processing unit 37. When the exposure (EXP) of the image sensor 32 is completed, the image data of the image sensor 32 is read (READ) by the image processing unit 37. In parallel with this reading, the image processing unit 37 calculates an AF evaluation value (IAF) (step S66 in the flowchart of FIG. 12).

  Note that the end timing of calculation of the AF evaluation value is set in advance so as to end before the fall of the vertical synchronization signal VD.

  The lens control unit 15 waits for the fall of the lens contact signal trigger (signal synchronized with the vertical synchronization signal VD) (step S125 in the flowchart of FIG. 18). When the fall is detected, the position of the focus lens 11a is acquired from the count value of the output pulse of the encoder 13 and stored in the memory 15a (step S126 in the flowchart of FIG. 18).

  At the same time, counting of an internal counter (not shown) of the lens control unit 15 is started (step S127 in the flowchart of FIG. 18), and the same time as the period TVD of the vertical synchronization signal stored in the lens control unit 15 in advance has elapsed. It counts until it completes (step S128 of the flowchart of FIG. 18). Then, the position of the focus lens 11a is acquired and stored in the memory 15a in the lens control unit 15 (step S126 in the flowchart of FIG. 18).

  The above operation is repeatedly executed in synchronization with the end of the TVD count of the internal counter of the lens control unit 15 during driving of the focus lens during the imager AF operation. When a lens stop command is transmitted from the control unit 45 to the lens control unit 15 by body / lens communication, the drive of the focus lens 11a is stopped (step S130 in the flowchart of FIG. 18).

  Further, when a lens position data transmission command is transmitted from the control unit 45 to the lens control unit 15, the position data of the focus lens 11a acquired corresponding to the AF evaluation value is transmitted from the lens control unit 15 to the control unit 45. (Step S132 in the flowchart of FIG. 18).

  As described above, in the fourth embodiment, first, the period information of the vertical synchronization signal that governs the operation timing of the image sensor 32 is transmitted from the camera body 30 to the interchangeable lens 10 in advance. Then, a trigger signal synchronized with the first vertical synchronization signal after the start of the imager AF is transmitted to the interchangeable lens 10. In this interchangeable lens 10, the focus lens position being driven is acquired in synchronization with the vertical synchronization signal cycle by measuring the time from the trigger signal. Further, after the peak search sequence of the imager AF is completed, the position data of the focus lens 11 a is transmitted to the camera body 30.

  Therefore, since the focus lens position synchronized with the imaging timing of the image sensor 32 can be acquired, even when the interchangeable lens 10 has the lens CPU, higher focus adjustment accuracy than the imager AF can be obtained. Further, since the lens contacts are used only for the first trigger signal, the number of lens contacts can be reduced, and the cost can be reduced and the performance of multifunction can be improved.

  Furthermore, since the focus lens position is not communicated during the peak search of the imager AF, the communication processing load of the control unit 45 and the lens control unit 15 can be reduced, the cost can be reduced by simplifying the circuit, and the peak search can be performed. It is possible to prevent performance degradation of other specifications that are processed in parallel.

  In the above-described embodiment, the position of the focus lens at the time of falling of the vertical synchronization signal VD is acquired, and an image is taken after the time has elapsed. Some deviation occurs in the timing of shooting the AF image. In order to eliminate this deviation, the position of the focus lens may be acquired after a predetermined time has elapsed from the fall of VD so that the position of the focus lens is acquired at the same time as the photographing.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

1 is a block diagram showing an overall configuration of a single-lens reflex type digital camera showing a first embodiment of the present invention. FIG. 3 is a block diagram illustrating a detailed configuration of a second focus detection unit 41 for explaining the imager AF. The imager AF will be described and is a diagram for explaining the relationship between the focus lens position and the AF evaluation value. The phase difference AF will be described, and a detailed configuration of the phase difference AF sensor unit 34 will be described. FIG. 6 is a diagram for explaining phase difference AF, and is an explanatory diagram for obtaining a shift amount of a photographing lens related to two subject images. The phase difference AF will be described, and is a block diagram illustrating a configuration of a portion related to phase difference detection in the present embodiment. It explains phase difference AF and is a diagram showing a relationship between a phase difference amount and a correlation function. 3 is a flowchart for explaining the operation of a main routine of the digital camera in the first embodiment. FIG. 9 is a flowchart for explaining a focus detection operation by a processing operation of a subroutine “imager AF” in step S9 of the flowchart of FIG. 8; 4 is a flowchart for explaining the operation of the interchangeable lens 10. It is a timing chart for explaining operation of imager AF. FIG. 10 is an operation flowchart of the control unit 45 for explaining the operation of the second embodiment and for explaining the focus detection operation by the “imager AF operation” performed in step S9 in the flowchart of FIG. 8. 7 is a flowchart for explaining the operation of the lens control unit 15 in order to explain the operation of the second embodiment. It is a timing chart for demonstrating operation | movement of 2nd Embodiment and demonstrating operation | movement of imager AF. It is a block diagram which shows the whole structure of the single-lens reflex type digital camera which shows the 3rd Embodiment of this invention. It is a flowchart for demonstrating the operation | movement of MF mode setting in the 3rd Embodiment of this invention. It is a timing chart for explaining the operation of the third embodiment and for explaining the operation of the imager AF. It is a flowchart for demonstrating operation | movement of the lens control part 15 in the 4th Embodiment of this invention. It is a timing chart for demonstrating operation | movement of 4th Embodiment and demonstrating operation | movement of imager AF.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Interchangeable lens, 11 ... Shooting lens system, 11a ... Imaging lens system, 12 ... Lens drive part, 13 ... Encoder, 15 ... Lens control part, 17 ... Timer, 20 ... Lens contact part, 30 ... Camera body, 31 ... Half mirror 32 ... Image sensor 34 ... Phase difference AF sensor unit 35 ... First focus detector 37 ... Image processor 38 ... LCD panel 39 ... Finder optical system 41 ... Second detector 45 ... Control part 47 ... First release switch (1RSW), 48 ... Second release switch (2RSW), 51 ... High pass filter (HPF), 52 ... A / D converter, 53 ... Focus detection area selection gate, 54 ... Adder, 61 ... Field mask, 62 ... Condenser lens, 63a, 63b ... Aperture mask, 64a, 64b ... Secondary optical system, 65a, 65b The photoelectric conversion element array, 68a, 68b ... pupil region, 71 ... A / D converter, 72 ... processing unit.

Claims (17)

An imaging system comprising a camera body and a lens unit that can be attached to and detached from the camera body,
The camera body
An image sensor for repeatedly photographing a subject imaged by the lens unit;
Control means for generating a command for controlling the driving of the lens of the lens unit;
A first transmission unit that transmits the command generated by the control unit and a synchronization signal that determines a shooting timing of the image sensor to the lens unit;
The lens unit
A focus lens for adjusting the focal position of the lens unit;
Lens control means for moving or stopping the focus lens along the optical axis in accordance with a command generated by the control means;
Position detection means for detecting a position along the optical axis of the focus lens at a timing substantially the same as the timing at which the imaging device shoots in synchronization with the synchronization signal;
An imaging system comprising: second transmission means for transmitting position information of the focus lens detected by the position detection means to the camera body.   2. The imaging system according to claim 1, wherein the second transmission unit transmits position information of the focus lens detected by the position detection unit to the camera body in synchronization with the synchronization signal. The lens unit further includes storage means for storing position information of the focus lens detected by the position detection means,
The imaging system according to claim 1, wherein the second transmission unit transmits the position information of the focus lens stored in the storage unit.   The second transmission unit transmits the position information of the focus lens stored in the storage unit when a predetermined command generated by the control unit transmitted from the first transmission unit is received. The imaging system according to claim 3.   5. The imaging system according to claim 4, wherein the predetermined command generated by the control unit is a command to stop the focus lens. An imaging system including a camera body and a lens unit that can be attached to and detached from the camera body,
The camera body
An image sensor for repeatedly photographing a subject imaged by the lens unit;
Control means for generating a lens movement start command for controlling the driving of the lens of the lens unit;
Trigger means for generating a trigger signal in synchronization with the synchronization signal immediately after generation of the lens movement start command generated by the control means;
A first transmission means for transmitting the lens movement start command generated by the control means, the trigger signal, and period information of the synchronization signal to the lens unit;
The lens unit
A focus lens for adjusting the focal position of the lens unit;
Lens control means for moving or stopping the focus lens along the optical axis in accordance with a lens movement start command generated by the control means;
Position detection means for detecting the position along the optical axis of the focus lens at the same timing as the timing at which the imaging device takes an image, which is repeated with the trigger signal as a starting point and in the same cycle as the synchronization signal;
An imaging system comprising: second transmission means for transmitting the position information of the focus lens detected by the position detection means to the camera body. The lens unit further comprises storage means for storing the position information of the focus lens detected by the position detection means,
The second transmission unit transmits the position information of the focus lens stored in the storage unit when a predetermined command generated by the control unit transmitted from the first transmission unit is received. The imaging system according to claim 6. The camera body further includes calculation means for calculating a degree of focus representing the degree of focus of the lens unit from image data of a subject photographed by the image sensor,
The control means generates a signal for controlling driving of the focus lens based on the degree of focus calculated by the calculation means and position information of the focus lens detected by the position detection means. The imaging system according to any one of 1 to 7. A camera equipped with a detachable lens unit,
An image sensor for repeatedly photographing a subject imaged by the lens unit;
Control means for generating a command for controlling the driving of the focus lens for adjusting the focal position of the lens unit;
Transmitting means for transmitting the command generated by the control means and a synchronization signal for determining the photographing timing of the image sensor to the lens unit;
Receiving means for receiving position information along the optical axis of the focus lens;
Computing means for calculating a degree of focus representing the degree of focus of the lens unit from image data of a subject photographed by the image sensor;
Have
The camera, wherein the control means generates a signal for controlling the driving of the focus lens based on the degree of focus calculated by the calculation means and the position information of the focus lens detected by the position detection means.   The camera according to claim 9, wherein the receiving unit receives position information of the focus lens in synchronization with the synchronization signal. Trigger means for generating a trigger signal in synchronization with the synchronization signal immediately after generating the lens movement start command generated by the control means;
The camera according to claim 9, wherein the transmission unit transmits the command generated by the control unit, the trigger signal, and period information of the synchronization signal to the lens unit. A lens unit that can be attached to a camera body having an image sensor for repeatedly photographing a subject,
A focus lens for adjusting the focal position of the lens unit;
Receiving means for receiving a signal from the camera body;
Lens control means for moving or stopping the focus lens along the optical axis in accordance with a command for controlling driving of the focus lens received by the receiving means;
Position detecting means for detecting a position along the optical axis of the focus lens at substantially the same timing as the timing at which the imaging element of the camera received by the receiving means captures;
Transmitting means for transmitting the position information of the focus lens detected by the position detecting means to the camera body;
A lens unit comprising:   The lens unit according to claim 12, wherein the transmission unit transmits the position information of the focus lens detected by the position detection unit to the camera body in synchronization with a synchronization signal received by the reception unit. . A storage means for storing position information of the focus lens detected by the position detection means;
The lens unit according to claim 12, wherein the transmission unit transmits the position information stored in the storage unit.   15. The transmission unit according to claim 14, wherein when the reception unit receives a predetermined command from the camera body, the transmission unit transmits the focus lens position information stored in the storage unit to the camera body. The lens unit described.   The lens unit according to claim 15, wherein the predetermined command received by the receiving means is a command to stop the focus lens. The receiving means receives the trigger signal and time interval information,
15. The lens unit according to claim 12, wherein the position detection unit repeatedly detects the position along the optical axis of the focus lens at the received time interval with the trigger signal as a starting point.

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