JP2012123051A - Imaging apparatus and lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: in a system in which a focus signal is delivered to a lens unit and control over automatic focus adjustment is performed on a lens side, when the drive condition of an imaging element of a camera body changes, since the lens side does not know the drive condition of the imaging element, the lens side cannot change drive timing of the lens in tune with accumulation timing of the imaging element or cannot refer to the focus signal correctly, resulting in a failure to judge a focusing direction correctly.SOLUTION: In an imaging apparatus, a lens unit for controlling drive timing of a focus lens based on information received from the imaging apparatus can be freely attached or detached. The imaging apparatus includes imaging means for performing photoelectric conversion of a subject image to generate an imaging signal and extraction means for extracting a focus signal from the imaging signal. The imaging apparatus transmits information on the focus signal and electrical charge accumulation start timing or end timing in a prescribed line among scan lines of the imaging means to the lens unit.

Description

  The present invention relates to an imaging apparatus in which a lens unit can be replaced, and a lens unit that can be attached to and detached from the imaging apparatus.

  In recent years, an autofocus device such as a video camera has a value obtained by detecting the sharpness of a screen from a video signal obtained by photoelectrically converting a subject image using an imaging device or the like as an AF evaluation value so that it is maximized. A focus adjustment method for controlling the focus lens position (hereinafter referred to as TVAF method) is the mainstream.

  As the TV AF AF evaluation value, the level of a high-frequency component of a video signal extracted by a band-pass filter in a certain band is generally used. When a normal subject image is photographed, the value increases as the focus is adjusted as shown in FIG. 2, and the point where the level becomes maximum is the in-focus position.

  Patent Document 1 discloses that this type of automatic focus adjustment method is used for a video camera in which a lens can be exchanged, a focus signal is transferred to the lens unit, and control of automatic focus adjustment is provided on the lens unit side. With this configuration, it is possible to determine the optimum response and the like for each lens regardless of what lens is attached, and to obtain optimum performance for all the removable lenses.

Japanese Patent Laid-Open No. 9-9130

  When the driving conditions of the image sensor of the camera body change, the accumulation signal of the image sensor and the timing to move the focus to infinity / closeness are matched, and the focus signal obtained from the image signal stored when the focus is moved to infinity / closeness It is necessary to correctly determine the in-focus direction by referring to it correctly. However, in Patent Document 1, since the driving condition of the image pickup device of the camera is not known on the lens side, the lens drive timing cannot be changed in accordance with the storage timing of the image pickup device, or the focus signal cannot be referred to correctly, and focusing is performed. The direction may not be determined correctly.

  In view of the above problems, the first aspect of the present invention includes a photographic optical system including a focus lens, and a detachable lens unit that controls the drive timing of the focus lens based on information received from the imaging device. An imaging unit that detects light that has passed through the optical system, accumulates charges in each scanning line, sequentially transfers the charges line by line, and generates an imaging signal; and a focus detection area in the imaging plane of the imaging unit Extraction means for extracting a focus signal from the corresponding imaging signal, and control means for transmitting the focus signal and information about charge accumulation start or end timing in a predetermined line among the scanning lines of the imaging means to the lens unit. It is an imaging device characterized by having.

  According to a second aspect of the present invention, there is provided an imaging means for detecting light passing through an imaging optical system, accumulating charges in each scanning line, sequentially transferring charges line by line to generate an imaging signal, and imaging by the imaging means The imaging optical system including a focus lens and the information received from the imaging device can be attached to and detached from an imaging device including an extraction unit that extracts a focus signal from an imaging signal corresponding to a focus detection area in a plane. A lens unit having a lens-side control unit that controls the driving of the focus lens based on the lens unit, the lens-side control unit receiving a focus signal and information on an imaging timing of the imaging unit from the imaging device, Based on the information regarding the imaging timing, the focus lens is stopped so as to stop driving the focus lens during charge accumulation in the focus detection region. A lens unit and controlling to calculate the driving start timing of the lens.

  According to the present invention, when the driving condition of the image sensor of the camera body changes, the accumulation timing of the image sensor and the timing of moving the focus to infinity / close can be matched. As a result, the in-focus direction can be correctly determined by correctly referring to the focus signal obtained from the image pickup signal accumulated when the focus is moved to infinity / closest.

Configuration of camera and lens according to an embodiment of the present invention The figure explaining a TVAF signal The figure explaining a TVAF frame TVAF flowchart Flow chart of micro drive Diagram explaining minute drive The figure explaining the accumulation | storage timing of a CMOS sensor Communication data and contents to be changed by communication data Processing timing chart of camera microcomputer and lens microcomputer The figure explaining the micro drive of the CMOS sensor with long transfer time Diagram explaining minute driving at slow shutter The figure explaining the case where the TVAF frame is at the top of the screen The figure explaining minute driving when there is a TVAF frame at the top of the screen Diagram explaining minute driving at high shutter speed Mountain climbing drive flowchart Diagram explaining hill-climbing drive

Example 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

  In the figure, reference numeral 117 denotes a lens unit, 118 denotes a camera body, and the lens unit 117 is detachable from the camera body 118 to constitute a so-called interchangeable lens system.

  The light from the subject includes a fixed first lens group 101 in the lens unit 117, a second lens group 102 that performs zooming, an aperture 103, a fixed third lens group 104, and a focus adjustment function. And a fourth lens group 105 (hereinafter referred to as a focus lens) having both a function for correcting the movement of the focal plane due to zooming, and forming an image on an image sensor such as a CMOS sensor in the camera body. .

  The image sensor 106 in the camera body is a photoelectric conversion element constituted by a CMOS sensor or the like. The image formed on the image sensor 106 is photoelectrically converted and amplified to an optimum level by the amplifier 107 and then input to the camera signal processing circuit 108. The image sensor 106 performs a charge accumulation operation in synchronization with the timing of the vertical synchronization signal (VD).

  A camera signal processing circuit 108 performs various image processing on the output signal from the amplifier 107 to generate a video signal. Reference numeral 109 denotes a monitor constituted by an LCD or the like, which displays a video signal from the camera signal processing circuit 108. A recording unit 110 records the video signal from the camera signal processing circuit 108 on a recording medium such as a semiconductor memory.

  Reference numeral 113 denotes a TVAF gate that passes only signals in an area used for focus detection, like the TVAF frame shown in FIG. The TVAF signal processing circuit 114 extracts a high frequency component from the signal that has passed through the TVAF gate 113 to generate a TVAF evaluation value signal. The TVAF evaluation value signal is output to the camera microcomputer 116. The TVAF evaluation value signal represents the sharpness (contrast state) of the video generated based on the output signal from the image sensor 106, but the sharpness changes depending on the focus state of the imaging optical system. As shown in FIG. 2, the signal represents the focus state of the imaging optical system.

  The camera microcomputer 116 as a control unit controls the operation of the entire video camera, and controls the TVAF gate 113 so as to set a TVAF frame at a predetermined ratio with respect to the imaging screen as shown in FIG. The camera microcomputer 116 transmits the TVAF evaluation value signal acquired from the TVAF signal processing circuit 114 to the lens microcomputer 115.

  Reference numeral 111 denotes a zoom drive source for moving the variable magnification lens 102. Reference numeral 112 denotes a focus drive source for moving the focus lens 105. The zoom drive source 111 and the focus drive source 112 are configured by actuators such as a stepping motor, a DC motor, a vibration motor, and a voice coil motor.

  The lens microcomputer 115 performs focus control in the TVAF method (hereinafter referred to as TVAF control). The lens microcomputer 115 receives the TVAF evaluation value from the camera microcomputer 116 and determines the driving amount and driving speed of the focus lens 105 based on the TVAF evaluation value. Based on the driving amount and the driving speed, the focus driving source 112 moves the focus lens 105 in the optical axis direction to perform focusing. By performing TVAF control on the lens side based on the TVAF evaluation value sent from the camera, appropriate TVAF control can be performed according to the characteristics of the lens.

  Next, TVAF control performed by the lens microcomputer 115 will be described with reference to FIGS. This TVAF control is executed according to a computer program stored in the lens microcomputer 115.

  FIG. 4 is a flowchart of TVAF control by the lens microcomputer 115.

  Step 401 indicates the start of processing. In step 402, a minute driving operation is performed, and it is determined whether the in-focus position is in focus or not in focus. A detailed description of the operation will be given in FIG.

  In Step 403, it is determined whether or not the focus is determined in Step 402. If the focus is determined, the process proceeds to Step 407 to perform the focus stop / restart determination process. If the focus is not determined, the process proceeds to Step 404.

  In Step 404, the focus lens is hill-climbed and driven in the direction determined in Step 402 at a predetermined speed, and a lens position where the TVAF evaluation value reaches a peak is searched. A detailed description of the operation will be given in FIG.

  In Step 405, the focus lens is returned to the focus lens position where the TVAF evaluation value during the hill-climbing driving operation is peak.

  In Step 406, it is determined whether or not the TVAF evaluation value has returned to the peak focus lens position. If it has returned to the peak focus lens position, it returns to Step 402 to perform the minute driving operation again. If it has not returned to the peak focus lens position, it returns to Step 405 and continues the operation to return to the peak focus lens position.

  Next, focus stop / restart determination processing from Step 407 will be described.

  In Step 407, it is determined whether or not there is a communication request from the camera, and if there is, the process proceeds to Step 408.

  In Step 408, communication with the camera is performed to acquire a TVAF evaluation value and the like.

  In Step 409, the focus lens is moved to the focus position determined to be in focus.

  In Step 410, it is determined whether or not the focus position has been moved. If it has moved, the process proceeds to Step 411. If not, the process returns to Step 407.

  In Step 411, the TVAF evaluation value at the focal point is held.

  In Step 412, it is determined whether there is a communication request from the camera, and if there is, the process proceeds to Step 413, and if not, the process waits in Step 412.

  In Step 413, communication with the camera is performed to acquire a TVAF evaluation value and the like.

  In Step 414, the TVAF evaluation value held in Step 411 is compared with the latest TVAF evaluation value acquired in Step 413, and it is determined whether the variation in the TVAF evaluation value is large. If the TVAF evaluation value fluctuates greatly, it is determined that the subject has changed, and the process proceeds to step 402 to restart the minute driving operation. If the TVAF evaluation value does not fluctuate, the process goes to step 412.

  Next, the minute driving operation will be described with reference to FIG.

  Step 501 indicates the start of processing.

  In Step 502, it is determined whether there is a communication request from the camera. If there is a communication request, the process proceeds to Step 503, and if there is not, the process waits in Step 502.

  In Step 503, information (CMOS sensor accumulation time, CMOS sensor transfer time, VD and communication delay time, TVAF frame position, TVAF evaluation value and information for determining the driving timing of the focus lens, which is a feature of the present invention, is communicated with the camera. Next, a TVAF evaluation value is obtained) is acquired.

  In Step 504, the driving cycle and the driving delay time are obtained based on the information obtained from the camera. Here, the drive delay time is the time from the camera-lens communication to the start of lens driving.

  In Step 505, it is determined whether or not the current Mode is 0. If it is 0, the process proceeds to Step 506, and the process at the lens position on the near side described later is performed.

<Processing at the closest lens position>
In Step 506, it is determined whether or not the TVAF evaluation value has already been acquired with Mode = 0, and if it has been acquired, the process proceeds to Step 508. It is stored as a TVAF evaluation value (since it is sometimes based on the accumulated sensor output).

  In Step 508, it is determined from the information fetched in Step 503 whether or not the next is the driving timing. If so, Mode is added in Step 509 (returns to 0 if 4 or more), and the process proceeds to Step 510. Otherwise, the mode is not added and the process proceeds to Step 510.

<Common processing>
In Step 510, if the direction determined to be the in-focus direction for a predetermined number of times 1 is the same, the process proceeds to Step 531; otherwise, the process proceeds to Step 511.

  In Step 511, if the two-focus lens has been reciprocated in the same area a predetermined number of times, the process proceeds to Step 532. If the focus lens has not been reciprocated in the same area a predetermined number of times, the process returns to Step 502.

  In Step 531, it is determined that the direction can be determined, the process proceeds to Step 534, the process is terminated, and the hill-climbing drive is started.

  In Step 532, the average position of the focus lens positions in the predetermined period 2 so far is calculated as the focal point. In Step 533, assuming that the in-focus determination has been made, the process proceeds to Step 534, where the processing is terminated and the process proceeds to in-focus stop / restart determination.

  In Step 512, it is determined whether or not the current Mode is 1, and if it is 1, the process proceeds to Step 513 to perform a process for driving the lens described below infinitely, and if not, the process proceeds to Step 519.

<Process to drive the lens infinitely>
In Step 513, the vibration amplitude and the center movement amplitude are calculated. Although not described in detail here, based on the depth of focus, it is common to decrease the amplitude when the depth is shallow and increase the amplitude when the depth is deep.

  In Step 514, the infinite TVAF evaluation value in Mode = 0 described above is compared with a close TVAF evaluation value in Mode = 3 described later. If the infinite TVAF evaluation value is larger than the close TVAF evaluation value, the process proceeds to Step 515 and infinite. If the side TVAF evaluation value is smaller than the closest TVAF evaluation value, the process proceeds to Step 516.

In Step 515, the drive amplitude is changed to
Drive amplitude = vibration amplitude + center movement amplitude.

In Step 516, the drive amplitude is changed to
Drive amplitude = vibration amplitude.

  In Step 517, driving is performed in an infinite direction with the amplitude determined in Step 515 or Step 516.

  In Step 518, Mode is added (when it becomes 4 or more, it is returned to 0), and the process proceeds to Step 510. Step 510 and subsequent steps are as described above.

  In Step 519, it is determined whether the current Mode is 2, and if it is 2, the process proceeds to Step 520, and the process at an infinite lens position described later is performed, otherwise, the process proceeds to Step 524.

<Processing at infinite lens position>
In Step 520, it is determined whether ModeAF = 2 has already acquired the TVAF evaluation value. If it has been acquired, the process proceeds to Step 522. If not, the TVAF evaluation value captured in Step 503 is set to Step 521. It is stored as a TVAF evaluation value (since it is sometimes based on the accumulated sensor output).

  In Step 522, it is determined from the information captured in Step 503 whether the next driving timing is reached. If so, Mode is added (returned to 0 when 4 or more), and the process proceeds to Step 523. Otherwise, the mode is not added and the process proceeds to Step 510.

  Step 510 and subsequent steps are as described above.

<Process to drive the lens close by>
In Step 524, the vibration amplitude and the center movement amplitude are calculated. Although not described in detail here, based on the depth of focus, it is common to decrease the amplitude when the depth is shallow and increase the amplitude when the depth is deep.

  In Step 525, the infinite TVAF evaluation value in Mode = 0 is compared with the close TVAF evaluation value in Mode = 2. If the close TVAF evaluation value is larger than the infinite TVAF evaluation value, the process proceeds to Step 526. If the side TVAF evaluation value is smaller than the infinite side TVAF evaluation value, the process proceeds to Step 527.

In Step 526, the drive amplitude is changed to
Drive amplitude = vibration amplitude + center movement amplitude.

In Step 527, the drive amplitude is changed to
Drive amplitude = vibration amplitude.

  In Step 528, driving is performed in the infinite direction with the amplitude determined in Step 526 or Step 527.

  In Step 529, Mode is added (when it becomes 4 or more, it is returned to 0), and the process proceeds to Step 510. Step 510 and subsequent steps are as described above.

  FIG. 6 shows the time course of the focus lens operation. Here, the horizontal axis is time, the downwardly convex period at the top is the V sync signal (VD) of the video signal, the diamond below is the accumulation time of the CMOS sensor, and the EVx below is the TVAF obtained at that timing The evaluation value, and the ↓ below it, indicates that the TVAF evaluation value is communicated from the camera to the lens, and the bottom is the focus lens position. The driving of the CMOS sensor will be described with reference to FIG. The left shows the imaging surface and scanning lines. The right shows the accumulation time and transfer time for each scanning line. Since the CMOS sensor is called a rolling shutter and releases the shutter for each scanning line, the storage time and transfer time are different between the upper part and the lower part of the screen as shown in the figure. This accumulation time is represented by a diamond in FIG. In FIG. 6, the charge accumulation for the first line of the CMOS sensor is completed at the timing of VD.

  As shown in FIG. 6, the TVAF evaluation value is monitored while moving the focus lens as close as possible to infinity, and the focus lens is moved in the in-focus direction. It is necessary to obtain a TVAF evaluation value from the video signal stored in. Therefore, the timing for driving the focus lens must be matched with the accumulation time of the CMOS sensor. Although not all of the CMOS sensor accumulation time is located near / infinite, the TVAF frame is set small relative to the imaging screen as shown in FIG. It is enough for accumulation. Here, the TVAF evaluation value EV3 for the charge accumulated in the CMOS sensor during the accumulation time 3 is communicated to the lens at time T3, and the TVAF evaluation value EV5 for the charge accumulated in the CMOS sensor during the accumulation time 5 is obtained at time T5. At time T5, the TVAF evaluation values EV3 and EV5 are compared. If EV5> EV3, the vibration center is moved, and if EV3> EV5, the vibration center is not moved. In this way, the in-focus direction is determined and the in-focus is determined.

  From now on, it will be described that the lens unit changes the TVAF control using the communication data which is a feature of the present invention. First, communication data, which is a feature of the present invention, will be described with reference to FIG. Examples of communication data include CMOS sensor accumulation time, CMOS sensor transfer time, communication delay time, TVAF frame position, and next TVAF evaluation value or TVAF evaluation value. Here, the communication delay time is the time from VD to the start of communication in this embodiment.

  These data are communicated from the camera to the lens, the focus drive as shown in FIG. 6 is determined in the lens, and the actual drive is performed.

  In this embodiment, assuming that 1V is 1/60 seconds, the lens stop time is set as follows based on the accumulation time and transfer time of the CMOS sensor.

From the accumulation time of the CMOS sensor,
Within 1 / 60S 4V cycle (stop time 1V)
1/60 to 1 / 30S 8V period (stop time 3V)
And

From the transfer time of the CMOS sensor,
Within 1 / 60S No change 1/60 to 1 / 30S Within Stop time is 1V.

  The drive delay time is adjusted from the accumulation time, communication delay time, and TVAF frame position, and the accumulation of the TVAF frame position and the timing at which the focus lens is positioned infinitely / infinitely are matched. This will be described with reference to FIG. In FIG. 9, the horizontal axis represents time, and shows the processing of the camera microcomputer and the processing of the lens microcomputer within 1V. First, immediately after the V synchronization, the camera microcomputer acquires a TVAF evaluation value. Including this data, data necessary for determining the focus drive is communicated by camera lens communication. After receiving the data necessary for determining the focus drive, the lens microcomputer calculates a target position for minute drive and a drive delay time for phase adjustment with the accumulation time. The lens microcomputer can know the VD timing from the received communication delay time. The charge accumulation start or end timing at the TVAF frame position can be calculated from the VD timing, the received CMOS sensor accumulation time, transfer time, and TVAF frame position information. The drive delay time is calculated so that the focus lens is stopped while the charge accumulation at the TVAF frame position is being performed. After waiting based on the calculated drive delay time, a lens drive process is performed to actually drive the lens.

  Further, the lens microcomputer matches the timing of lens driving at the time of slow shutter and acquisition of the evaluation value depending on whether the TVAF evaluation value comes from the camera in the next communication. Details are left to the description of FIG.

  As described above, based on the information received from the camera microcomputer, the lens microcomputer adjusts the focus lens stop time and drive delay time. On the other hand, a method of calculating the stop time and the drive delay time with the camera microcomputer and transmitting them to the lens microcomputer is also assumed. In this case, the lens microcomputer needs to drive the focus lens at a timing instructed from the camera. However, when the driving speed is insufficient, there is a possibility that the driving cannot be completed within the time instructed from the camera. Therefore, if the stop time and drive delay time are adjusted on the lens side as in the present invention, the lens microcomputer can adjust at what timing the lens is driven according to the drive speed and drive amount of the focus lens. TVAF control corresponding to the characteristics of each lens is possible.

  Next, a specific example will be described to change the driving of the lens using these communication data.

<When transfer time is long>
A case where the transfer time is long will be described with reference to FIG. FIG. 10 shows a case where the accumulation time is 1/60 seconds and the transfer time is 1/30 seconds. The time required from the start to the end of sensor accumulation per frame is 1/30 (1/60 × 2) seconds in FIG. 6 as a whole, but in FIG. 10 is 1/20 (1/60 × 3). It is second. For this reason, by adding 1 V to the stop time from the case of FIG. 6, a stop time sufficient for storing the TVAF frame position is secured. In addition, the drive delay time is adjusted based on the received communication delay time information, and the accumulation of the TVAF frame position is matched with the timing at which the focus lens is positioned close to / infinitely. This calculation is performed in Step 504 of FIG. In FIG. 10, the TVAF evaluation value EV4 for the charge accumulated in the CMOS sensor during the accumulation time 4 is communicated to the lens at time T4, and the TVAF evaluation value EV7 for the charge accumulated in the CMOS sensor during the accumulation time 7 is obtained. At time T7, which is taken in at time T7, the TVAF evaluation values EV4 and EV7 are compared. If EV7> EV4, the vibration center is moved, while if EV4> EV7, the vibration center is not moved. In this way, the in-focus direction is determined and the in-focus is determined.

<When accumulation time is long>
A case where the accumulation time is long (slow shutter) will be described with reference to FIG. FIG. 11 shows an example in which the accumulation time is 1/30 (1/60 × 2) seconds and the transfer time is 1/60 seconds. In FIG. 6, the time required from the start to the end of sensor accumulation per frame is 1/30 (1/60 × 2) seconds, but in FIG. 11, it is 1/20 (1/60 × 3). It is second. For this reason, by setting the stop time to 3 V, a stop time sufficient for storing the TVAF frame position is secured. Also in the case of FIG. 11, the drive delay time is adjusted based on the received communication delay time information, and the accumulation of the TVAF frame position is matched with the timing at which the focus lens is positioned infinitely / infinitely. In FIG. 11, the TVAF evaluation value EV2 for the charge accumulated in the CMOS sensor during the accumulation time 2 is communicated to the lens at time T2, and the TVAF evaluation value EV4 for the charge accumulated in the CMOS sensor during the accumulation time 4 is obtained. At time T4, which is taken in at time T4, the TVAF evaluation values EV2 and EV4 are compared. If EV4> EV2, the vibration center is moved, whereas if EV2> EV4, the vibration center is not moved. In this way, the in-focus direction is determined and the in-focus is determined.

  Further, the period in which the TVAF evaluation value is obtained is 1/60 seconds in FIG. 6 but is 1/30 (1/60 × 2) seconds in FIG. 11, and the TVAF evaluation value may not be transmitted during communication. is there. Therefore, phase matching of the drive timing with the timing at which the TVAF evaluation value is obtained is performed depending on whether or not the TVAF evaluation value is obtained in the next communication. For example, in FIG. 11, when a TVAF evaluation value is output in the next communication at time T6 ′, driving of the lens is started after the drive delay time has elapsed from time T6 ′. The calculation of the driving cycle is performed in Step 504 in FIG. 5, and the phase alignment between the timing at which the TVAF evaluation value is obtained and the driving timing is performed in Step 508 and Step 522.

<When the TVAF frame is at the top of the screen>
A case where the TVAF frame is at the top of the screen as shown in FIG. 12 will be described. In the case of FIG. 12, the timing at which the lens needs to be stopped during the accumulation time is therefore different from that in FIG. FIG. 13 shows an example of minute driving when the TVAF frame is at the top of the screen as shown in FIG. The drive delay time is adjusted to match the accumulation of the TVAF frame position with the timing at which the focus lens is positioned near / infinitely. This calculation is performed in Step 504 of FIG. In FIG. 13, the TVAF evaluation value EV3 for the charge accumulated in the CMOS sensor during the accumulation time 3 is communicated to the lens at time T3, and the TVAF evaluation value EV5 for the charge accumulated in the CMOS sensor during the accumulation time 5 is obtained. Captured at time T5. At time T5, the TVAF evaluation values EV3 and EV5 are compared, and if EV5> EV3, the vibration center is moved, while if EV3> EV5, the vibration center is not moved. In this way, the in-focus direction is determined and the in-focus is determined. In FIG. 13, the drive delay time is not provided. However, the present invention is not limited to this, and the drive delay time may be appropriately adjusted.

<When accumulation time is short>
A case where the accumulation time is short (high-speed shutter) will be described with reference to FIG. FIG. 14 shows a case where the accumulation time is 1/120 seconds as an example. The time taken from the start to the end of sensor accumulation per frame in FIG. 6 was 1/30 (1/60 × 2) seconds as a whole, but in FIG. 14, it is 3/120 (1/60 + 1/120). The time is getting shorter. For this reason, by adjusting the driving delay time, the accumulation of the TVAF frame position and the timing of the focus lens positioned close to / infinite are matched. This calculation is performed in Step 504 of FIG. In FIG. 14, the TVAF evaluation value EV3 for the charge accumulated in the CMOS sensor during the accumulation time 3 is communicated to the lens at time T3, and the TVAF evaluation value EV5 for the charge accumulated in the CMOS sensor during the accumulation time 5 is obtained. At time T5, which is taken in at time T5, the TVAF evaluation values EV3 and EV5 are compared, and if EV5> EV3, the vibration center is moved, while if EV3> EV5, the vibration center is not moved. In this way, the in-focus direction is determined and the in-focus is determined.

  As described above, necessary data is sent from the camera to the lens unit with respect to the difference in driving of the CMOS sensor and the position of the TVAF frame, and the driving of the lens is changed based on the data acquired by the lens unit. In this way, regardless of how the CMOS sensor is driven, the lens stop time and the drive delay time are adjusted accordingly, and the accumulation of the TVAF frame position and the timing at which the focus lens is positioned close / infinite Can be combined. As a result, the lens side can acquire the TVAF evaluation value from the camera at an appropriate timing.

  The setting of the lens stop time and the drive delay time described above is not limited to this embodiment, and can be appropriately changed within the scope of the gist of the present invention. In this embodiment, the communication delay time is the time from VD to the start of communication. However, the present invention is not limited to this as long as it represents the phase relationship between sensor accumulation and communication. For example, the time from the end of charge accumulation on the first line of the sensor to the start of communication may be sent to the lens.

  In this embodiment, the case where the charge accumulation of the first line of the image sensor 106 is completed at the timing of VD is shown, but the present invention is not limited to the first line. Further, the present invention can be applied even when charge accumulation of a predetermined line is started by VD.

  Next, the hill-climbing driving operation will be described with reference to FIG.

  Step 1501 indicates the start of processing.

  In Step 1502, it is determined whether or not there is a communication request from the camera. If there is a communication request, the process proceeds to Step 1503. If there is no communication request, the process waits in Step 1502.

  In Step 1503, communication with the camera is performed to acquire TVAF evaluation values and information (CMOS sensor accumulation time, CMOS sensor transfer time, VD and communication delay time) for determining the focus lens drive timing, which is a feature of the present invention.

  In Step 1504, the mountain climbing drive speed is set. Although not described in detail here, on the basis of the depth of focus, it is common to decrease the speed when the depth is shallow and increase the speed when the depth is deep.

  In Step 1505, it is determined whether or not the TVAF evaluation value captured in Step 1503 is smaller by a predetermined amount than the previous TVAF evaluation value. If not smaller, the process proceeds to Step 1506, and if smaller, the process proceeds to Step 1511. Here, the predetermined amount is a value determined in consideration of the S / N of the TVAF evaluation value, and is a value equal to or larger than the fluctuation range of the TVAF evaluation value when the subject is fixed and the focus lens is fixed. Otherwise, hill-climbing cannot be driven in the correct direction due to the influence of the variation of the TVAF evaluation value.

  In Step 1506, it is determined whether or not the focus lens has reached the infinite end. The infinity end is the position closest to the infinity of the focus lens stroke determined by design. If the end point has been reached, the process proceeds to Step 1507. If not reached, the process proceeds to Step 1508.

  In Step 1508, it is determined whether or not the focus lens has reached the close end. The closest end is the position closest to the focus lens stroke determined by design. If the close end has been reached, go to Step 1509. If not reached, the process proceeds to Step 1510.

  In Steps 1507 and 1509, a flag for storing the inverted end is set, and the process proceeds to Step 1513. The focus lens is inverted in the reverse direction and hill-climbing driving is continued.

  In Step 1510, the focus lens is hill-climbed and driven in the forward direction at the speed determined in Step 1504, and the process proceeds to Step 1502 to end the current process.

  In Step 1511, if the TVAF evaluation value has not decreased beyond the peak, the process proceeds to Step 1512. If the TVAF evaluation value has decreased beyond the peak, the process proceeds to Step 1514, the hill-climbing drive is terminated, the process proceeds to Step 1515, the process is terminated, and the minute drive is performed. Move to operation.

  In Step 1512, it is determined whether or not it has been continuously decreased by a predetermined number of times. If it has been continuously decreased, the process proceeds to Step 1513, and if not continuously decreased, the process proceeds to Step 1510.

  In Step 1510, the focus lens is hill-climbed and driven in the forward direction at the speed determined in Step 1504, and the process proceeds to Step 1502 to end the current process.

  In Step 1513, the focus lens is hill-climbed at the speed determined in Step 1504 in the opposite direction to the previous time, and the process proceeds to Step 1502 to end the current process.

  FIG. 16 shows the movement of the lens during the hill-climbing driving operation. Here, since A has decreased beyond the peak, the hill-climbing driving operation is terminated because there is an in-focus point, and the operation shifts to a minute driving operation. On the other hand, B has a peak and has decreased, so the direction is wrong. Invert and continue the hill-climbing drive operation.

  As described above, the lens microcomputer 115 is controlled so that the TVAF evaluation value is always maximized by moving the focus lens while repeating the restart determination → small drive → hill climbing drive → small drive → restart determination. Keep in focus.

  As described above, necessary data is sent from the camera to the lens unit to change the driving of the lens based on the data acquired by the lens unit with respect to the difference in driving of the image sensor of the camera body and the difference in TVAF frame position. As a result, in a system in which a TVAF evaluation value is sent to the lens unit and AF control is performed within the lens, it is possible to match the accumulation timing of the image sensor with the timing of moving the focus to infinity / closeness, and the focus signal is correctly set on the lens side. The in-focus direction can be determined by referring.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 105 Focus lens 106 Image pick-up element 112 Focus drive source 113 TVAF gate 114 TVAF signal processing circuit 115 Lens microcomputer 116 Camera microcomputer 117 Lens unit 118 Camera body

Claims (12)

A photographic optical system including a focus lens is provided, and a lens unit for controlling the drive timing of the focus lens based on information received from the imaging device can be attached and detached.
Imaging means for detecting light that has passed through the imaging optical system, accumulating charges in each scanning line, and sequentially transferring the charges line by line to generate an imaging signal;
An extraction means for extracting a focus signal from an imaging signal corresponding to a focus detection area in an imaging surface of the imaging means;
The focus signal extracted by the extraction unit is transmitted to the lens unit, and the lens unit can calculate the charge accumulation start or end timing of the line from which the focus signal is extracted. An image pickup apparatus comprising: control means for transmitting information about charge accumulation start or end timing in a predetermined line to the lens unit.   The control means completes the charge transfer of all lines after the charge transfer time information about the time required for the charge storage per line of the image pickup means and the charge transfer of the first line of the image pickup means is started. The image pickup apparatus according to claim 1, wherein charge transfer time information about a time until is transmitted to the lens unit.   2. The control unit according to claim 1, wherein the control unit performs control so as to set a position of a focus detection region in an imaging surface of the imaging unit, and transmits information about the position of the focus detection region to the lens unit. Or the imaging device of 2.   The imaging device according to any one of claims 1 to 3, wherein the control unit notifies whether or not to send a focus signal in the next communication in communication with the lens unit. An imaging unit that detects light passing through the imaging optical system, accumulates electric charge in each scanning line, and sequentially transfers the charge line by line to generate an imaging signal; and an in-focus detection area in the imaging plane of the imaging unit Can be attached to and detached from an imaging device having an extraction means for extracting a focus signal from an imaging signal corresponding to
The imaging optical system including a focus lens;
A lens unit having lens-side control means for controlling driving of the focus lens based on information received from the imaging device,
The lens-side control unit receives a focus signal and information related to the imaging timing of the imaging unit from the imaging device, and drives the focus lens during charge accumulation in the focus detection region based on the information related to the imaging timing. The lens unit is characterized by calculating and controlling the drive start timing of the focus lens so as to stop.   The lens-side control unit receives information about the charge accumulation start or end timing in a predetermined line among the scanning lines of the imaging unit from the imaging device, performs communication based on the information, and then performs the control of the focus lens. The lens unit according to claim 5, wherein the driving timing is controlled by calculating a time until driving is started.   The information related to the imaging timing includes the charge accumulation time information about the time required for the charge accumulation per line of the imaging means, and the charge transfer of all lines after the charge transfer of the first line of the imaging means is started. 7. The lens unit according to claim 5, wherein the lens unit is charge transfer time information about a time until completion of.   The lens-side control means controls the stop time of the focus lens to be longer when the charge accumulation time is the second charge accumulation time longer than the first charge accumulation time than when the first charge accumulation time is reached. The lens unit according to claim 5, wherein:   9. The lens unit according to claim 5, wherein the lens-side control unit controls the drive timing of the focus lens based on the charge accumulation time received from the imaging device. .   The lens side control means controls the stop time of the focus lens to be longer when the second charge transfer time is longer than the first charge transfer time than when the first charge transfer time is longer than the first charge transfer time. The lens unit according to claim 5, wherein:   The lens-side control unit receives information about the position of a focus detection region in the imaging plane of the imaging unit from the imaging device, and controls the drive timing of the focus lens based on the information. The lens unit according to claim 5.   The lens-side control means receives information about whether or not a focus signal is sent in the next communication from the imaging apparatus, and controls the drive timing of the focus lens based on the information. The lens unit according to any one of 5 to 11.

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