JP2013080249A - Imaging apparatus and lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that, in an interchangeable lens system, when a lens unit side cannot complete movement of a focus lens within predetermined time, there is possibility that a camera side cannot perform focus adjustment control by using an appropriate AF evaluation value.SOLUTION: When a focus lens cannot be moved by a movement amount received from an imaging apparatus within predetermined time, lens side control means notifies to the imaging apparatus that the focus lens is not movable, and moves the focus lens by the movement amount. When determining, on the basis of notification received from a lens unit, that the focus lens cannot be moved by the movement amount within the predetermined time, control means in an imaging apparatus side generates an AF evaluation value from a charge storage of imaging means during a period until the focus lens stops, and perform focus adjustment control by using the AF evaluation value, after waiting completion of movement of the focus lens.

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 system such as a video camera has a maximum AF evaluation value, which is a value obtained by detecting the sharpness of a screen from a video signal obtained by photoelectrically converting a subject image with an image sensor or the like. A method of controlling the focus lens position (hereinafter referred to as TVAF method) is the mainstream as an autofocus method of the image pickup apparatus.

  The AF evaluation value of the TVAF method is generally generated using the level of the high frequency component of the video signal extracted by a band pass filter in a certain band. FIG. 2 shows an example of the relationship between the focus lens position and the AF evaluation value in the TVAF method. When a normal subject image is photographed, the AF evaluation value increases as the focus is adjusted as shown in FIG. 2, and the point where the level is maximum is the in-focus position.

  In Patent Document 1, in a video camera in which a lens unit can be replaced, a main body microcomputer transmits a focus signal extracted from an imaging signal in the camera body to the lens unit, and the lens microcomputer in the lens unit performs AF control. Have been described. The lens microcomputer controls the driving of the focus lens based on the received focus signal.

Japanese Patent Laid-Open No. 9-9130

  On the other hand, a system is assumed in which a microcomputer in the camera determines drive control of the focus lens based on the extracted focus signal, and a focus lens drive command is transmitted to the lens microcomputer. Here, when a wobbling operation is performed using a vertical synchronization signal that is synchronized with the exposure of the image sensor, it is necessary to stop the focus lens during charge accumulation for generating a focus signal. Therefore, the timing at which the focus lens can be moved is limited to a time during which charge accumulation for generating a focus signal is not performed. Therefore, the lens microcomputer must complete the movement of the focus lens according to an instruction from the camera microcomputer during the timing. However, if the focus lens cannot reach the target position instructed from the camera microcomputer in time, the camera microcomputer may not be able to perform focus adjustment control using an appropriate AF evaluation value.

  In view of the above problems, the first aspect of the present invention is capable of detaching a lens unit including an imaging optical system including a focus lens, detecting light passing through the imaging optical system, and accumulating charges. An imaging means for generating an imaging signal by transferring the image, 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, and a focus signal extracted by the extraction means And a control unit that determines the amount of movement of the focus lens and transmits information on the amount of movement to the lens unit, the control unit using the amount of movement transmitted to the lens unit. Information indicating whether the focus lens can move within a predetermined time is received from the lens unit, and the focus lens can move the movement amount within the predetermined time. When receiving the information indicating that there is, the next movement amount of the focus lens is determined based on the first focus signal extracted from the imaging signal corresponding to the charge accumulated in the focus detection area at the first timing. When the information indicating that the movement amount of the focus lens is not movable within the predetermined time is received, the focus lens is used after the movement of the focus lens is completed without using the first focus signal. The next movement amount of the focus lens is determined based on the second focus signal extracted from the imaging signal corresponding to the electric charge accumulated in the focus detection area at the second timing when the focus lens is stopped. It is an imaging device.

  The second aspect of the present invention is based on an imaging unit that detects light passing through the imaging optical system, accumulates charges, transfers the accumulated charges to generate an imaging signal, and a focus signal extracted from the imaging unit. The imaging optical system including a focus lens, a focus driving unit for driving the focus lens, and a control unit of the mounted imaging device, which can be mounted on an imaging device including a control unit that determines focus adjustment control A lens unit that receives information for focus adjustment from the lens and controls the driving of the focus driving unit based on the information. The lens side control unit receives the information from the control unit. Receiving information on the amount of movement of the focus lens, and notifying the control means whether or not the focus lens can move within a predetermined time. It is a lens unit that.

  The third aspect of the present invention is based on an imaging means for detecting light passing through an imaging optical system, accumulating charges, transferring the accumulated charges to generate an imaging signal, and a focus signal extracted from the imaging signal. The image pickup optical system including the focus lens, the focus drive means for driving the focus lens, and the control of the attached image pickup apparatus can be attached to the image pickup apparatus including the control means for determining the focus adjustment control. A lens unit having a lens side control unit that receives information for focus adjustment from the unit and controls the driving of the focus driving unit based on the information, the lens side control unit to the control unit A predetermined signal is transmitted, and the predetermined signal is a signal for changing a focus signal used for focus adjustment control by the control means according to the signal level. It is a unit.

  According to the present invention, when the lens unit cannot complete the movement of the focus lens within a predetermined time, the AF evaluation value is generated from the charge accumulation while the focus lens is stopped after waiting for the movement to be completed. It becomes possible to perform appropriate AF control by using.

Configuration of a camera according to an embodiment of the present invention The figure explaining TVAF evaluation value signal The figure explaining a TVAF frame Flowchart of TVAF according to an embodiment of the present invention The flowchart which shows the control of the micro drive of embodiment of this invention The figure explaining the micro drive of embodiment of this invention The figure explaining the accumulation | storage timing of a CMOS sensor Timing chart of processing of camera microcomputer and lens microcomputer of embodiment of the present invention The figure which shows the communication data of the camera microcomputer and lens microcomputer of embodiment of this invention The figure explaining the micro drive at the time of drive delay generation of a focus lens in an embodiment of the present invention The flowchart which shows the control of the hill-climbing drive of embodiment of this invention 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 the configuration of a camera that employs an interchangeable lens system. In the figure, the lens unit 117 is detachable from the camera unit 118.

  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 an image pickup element 106 as an image pickup means in the camera unit through an image pickup optical system including a fourth lens group 105 (hereinafter referred to as a focus lens) having a competition function for correcting the movement of the focal plane due to zooming. Is imaged. The image sensor 106 in the camera unit 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 camera signal processing circuit 108 performs various kinds of image processing on the output signal from the amplifier 107 to generate a video signal. A monitor 109 constituted by an LCD or the like displays a video signal from the camera signal processing circuit 108. The recording unit 110 records the video signal from the camera signal processing circuit 108 on a recording medium such as a semiconductor memory.

  The TVAF gate 113 passes only the signal of the region used for focus detection out of the output signals of all the pixels from the amplifier 107. The TVAF signal processing circuit 114 serving as an extraction unit extracts a high frequency component from the signal that has passed through the TVAF gate 113 and generates 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. Since the contrast state changes depending on the focus state of the imaging optical system, the TVAF evaluation value signal eventually becomes a signal representing the focus state of the imaging optical system as shown in FIG.

  FIG. 3 shows a TVAF frame on the imaging screen. 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 determines a drive command for the focus lens 105 based on the TVAF evaluation value signal acquired from the TVAF signal processing circuit 114, and transmits it to the lens microcomputer 115 as lens-side control means.

  The zoom drive source 111 is a drive source for moving the variable magnification lens 102. The focus drive source 112 (drive means) is a 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 controls the drive of the focus drive source 112 based on the drive command received from the camera microcomputer 116, and moves the focus lens 105 in the optical axis direction to perform focusing.

  Next, TVAF control performed by the camera microcomputer 116 will be described with reference to FIGS. This TVAF control is executed according to a computer program stored in the camera microcomputer 116. The actual focus lens 105 is driven by the lens microcomputer 115.

  Step 401 indicates the start of processing. In step 402, the camera microcomputer 116 instructs the lens microcomputer 11 to perform a minute driving operation. Then, the camera microcomputer 116 determines whether the in-focus position is in focus or not in-focus based on the result of the minute driving operation. A detailed description of the operation will be given in FIG. In Step 403, the camera microcomputer 116 determines whether or not the focus is determined in Step 402. The camera microcomputer 116 proceeds to Step 407 when the in-focus determination can be performed, performs the focus stop / restart determination process, and proceeds to Step 404 when the in-focus determination has not been performed.

  In Step 404, the camera microcomputer 116 instructs the lens microcomputer 11 to drive the focus lens 105 in a direction determined in Step 402 at a predetermined speed, and determines the focus lens position where the TVAF evaluation value peaks during the hill-climbing drive process. look for. A detailed description of the operation will be given in FIG. In Step 405, the camera microcomputer 116 instructs the lens microcomputer 115 to return the focus lens 105 to the focus lens position where the TVAF evaluation value acquired during the hill-climbing driving operation reaches its peak. In step 406, the camera microcomputer 116 determines whether the focus lens 105 has returned to the focus lens position where the TVAF evaluation value reaches its peak. When the camera microcomputer 116 determines that the focus lens 105 has returned to the focus lens position at which the TVAF evaluation value reaches its peak, the camera microcomputer 116 returns to Step 402 and instructs the lens microcomputer 115 to perform a minute driving operation again. On the other hand, if the camera microcomputer 116 determines that the focus lens 105 has not returned to the focus lens position where the TVAF evaluation value reaches its peak, the camera microcomputer 116 returns to Step 405 and returns the focus lens 105 to the focus lens position where the TVAF evaluation value reaches its peak. The lens microcomputer 115 is instructed to continue the operation.

  Next, focus stop / restart determination processing from Step 407 will be described. In Step 407, the camera microcomputer 116 acquires a TVAF evaluation value from the TVAF signal processing circuit 114. In Step 408, the camera microcomputer 116 communicates a control command to the lens microcomputer 115 so as to move the focus lens to the focus position determined to be in focus. In Step 409, the camera microcomputer 116 communicates with the lens microcomputer 115 to acquire the focus lens position. In Step 410, the camera microcomputer 116 determines whether or not the focus lens 105 has moved to the in-focus position. If the camera microcomputer 116 determines that the focus lens 105 has moved to the in-focus position, the process proceeds to step 411, and if it determines that the focus lens 105 has not moved, the process returns to step 407. In Step 411, the camera microcomputer 116 holds the TVAF evaluation value at the in-focus position. In Step 412, the camera microcomputer 116 acquires the latest TVAF evaluation value. In Step 413, the camera microcomputer 116 compares the TVAF evaluation value held in Step 411 with the latest TVAF evaluation value acquired in Step 412, and determines whether or not the variation in the TVAF evaluation value is large. If the camera microcomputer 116 determines that the TVAF evaluation value has greatly fluctuated, the camera microcomputer 116 instructs the lens microcomputer 115 to proceed to Step 402 and resume the minute driving operation, assuming that the subject has changed. On the other hand, if the camera microcomputer 116 determines that the TVAF evaluation value has not fluctuated significantly, the process returns to Step 412.

  Next, the minute driving operation in Step 402 will be described. FIG. 5 is a flowchart of minute drive control. Step 501 indicates the start of processing. In Step 502, the camera microcomputer 116 communicates with the lens microcomputer 115. The camera microcomputer 116 transmits a focus lens drive command (target position and drive speed of the focus lens 105) to the lens microcomputer 115. The camera microcomputer 116 also receives focus lens position and target position arrival determination data from the lens microcomputer 115.

  In Step 503, the camera microcomputer 116 obtains a drive cycle for driving the focus lens 105 and a drive delay time from the communication until the focus lens 105 starts to be driven. The drive delay time is a time for adjusting the accumulation time and the focus lens driving phase so that the focus lens 105 is stopped during the charge accumulation of the image sensor 106 in the region corresponding to the TVAF frame. In this embodiment, the driving cycle is set to 2V, and the focus lens 105 is driven during 1V and stopped during 1V. Note that the driving cycle is not limited to this.

  In Step 504, the camera microcomputer 116 determines whether the current Mode is 0. If it is 0, the camera microcomputer 116 proceeds to Step 505 and performs processing at the focus lens position on the near side described later. If Mode is not 0, the process proceeds to Step 511.

<Processing at the closest focus lens position>
In Step 505, the camera microcomputer 116 determines whether or not the process at the closest focus lens position is the first time (it is not NG in the following arrival determination in the previous process). If No, the process proceeds to Step 507. If Yes, in Step 506, the camera microcomputer 116 stores the TVAF evaluation value as the TVAF evaluation value on the infinity side (because it is based on the sensor output accumulated when the focus lens is on the infinity side).

  In Step 507, the camera microcomputer 116 determines whether the target position arrival determination received from the lens microcomputer 115 is OK. If it is not OK, the process proceeds to Step 509. If it is OK, the camera microcomputer 116 adds Mode (returns to 0 if it is 4 or more) and proceeds to Step 509.

<Common processing>
In step 509, the camera microcomputer 116 proceeds to step 529 if the direction determined to be the in-focus direction is the same one consecutive number of times, and proceeds to step 529, otherwise proceeds to step 510. In Step 510, if the two-focus lens is repeatedly reciprocated in the same area for a predetermined number of times, the process proceeds to Step 530. If the two-focus lens is not reciprocated in the same area for a predetermined number of times, the process returns to Step 502.

  In Step 529, assuming that the camera microcomputer 116 has been able to determine the direction, the process proceeds to Step 532, where the processing is terminated and the process proceeds to hill-climbing driving.

  In Step 530, the camera microcomputer 116 calculates the average position of the focus lens position during the period in which the two-focus lens 105 has reciprocated a predetermined number of times as the in-focus position. In Step 531, the camera microcomputer 116 determines that the in-focus state has been achieved, and proceeds to Step 532 to end the processing and shift to in-focus stop / restart determination.

  In Step 511, the camera microcomputer 116 determines whether the current Mode is 1. If it is 1, the process proceeds to Step 512, and a process for driving the focus lens 105 described below infinitely is performed. If it is not 1, the process proceeds to Step 518.

<Process to drive the focus lens infinitely>
In Step 512, the camera microcomputer 116 calculates the vibration amplitude and the center movement amplitude. 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 513, the camera microcomputer 116 compares the infinite TVAF evaluation value at Mode = 0 described above with the near-side TVAF evaluation value at Mode = 2 described later. If the infinite TVAF evaluation value is larger than the closest TVAF evaluation value, the process proceeds to Step 514, and if the infinite side TVAF evaluation value is smaller than the closest TVAF evaluation value, the process proceeds to Step 515.

  In Step 514, the camera microcomputer 116 sets the drive amplitude of the focus lens 105 as drive amplitude = vibration amplitude + center movement amplitude. In Step 515, the camera microcomputer 116 sets the drive amplitude of the focus lens 105 as drive amplitude = vibration amplitude. In Step 516, the camera microcomputer 116 instructs the lens microcomputer 115 to drive the focus lens 105 in the infinite direction with the amplitude determined in Step 514 or Step 515.

  In Step 517, the camera microcomputer 116 adds Mode (returns to 0 when 4 or more) and proceeds to Step 509. Step 509 and subsequent steps are as described above.

  In Step 518, the camera microcomputer 116 determines whether the current Mode is 2. If it is 2, the process proceeds to Step 519, and the camera microcomputer 116 performs processing at an infinite focus lens position described later, and if it is not 2, the process proceeds to Step 523.

<Processing at infinite focus lens position>
In Step 519, the camera microcomputer 116 determines whether or not the process at the infinite focus lens position is the first time (it is not NG in the following arrival determination in the previous process). If No, the process proceeds to Step 521; if Yes, in Step 520, the camera microcomputer 116 stores the TVAF evaluation value as the TVAF evaluation value on the near side (because it is based on the sensor output accumulated when the focus lens is on the close side).

  In Step 521, the camera microcomputer 116 determines whether the target position arrival determination received from the lens microcomputer 115 is OK. If it is not OK, the process proceeds to Step 509. If it is OK, the camera microcomputer 116 adds Mode (returns to 0 when it is 4 or more) in Step 522, and then proceeds to Step 509. Step 509 and subsequent steps are as described above.

<Process to drive the focus lens close>
In Step 523, the camera microcomputer 116 calculates the vibration amplitude and the center movement amplitude of the focus lens 105. 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.

  At Step 524, the camera microcomputer 116 compares the infinite TVAF evaluation value at Mode = 0 and the near-side TVAF evaluation value at Mode = 2. If the near side TVAF evaluation value is larger than the infinite side TVAF evaluation value, the process proceeds to Step 525, and if the near side TVAF evaluation value is smaller than the infinite side TVAF evaluation value, the process proceeds to Step 526.

  In Step 525, the camera microcomputer 116 sets the drive amplitude of the focus lens 105 as drive amplitude = vibration amplitude + center movement amplitude. In Step 526, the camera microcomputer 116 sets the drive amplitude of the focus lens 105 as drive amplitude = vibration amplitude.

  In Step 527, the camera microcomputer 116 instructs the lens microcomputer 115 to drive the focus lens 105 in the infinite direction with the amplitude determined in Step 525 or Step 526.

  In Step 528, the camera microcomputer 116 adds Mode (returns to 0 when it becomes 4 or more), and proceeds to Step 509. Step 509 and subsequent steps are as described above.

  FIG. 6 shows the time course of the focus lens operation. Here, the horizontal axis represents time, and the downward convex period at the top represents the V synchronization signal of the video signal. The diamond below the V sync signal represents the CMOS sensor accumulation time, the EVx below it represents the TVAF evaluation value obtained at that timing, and the focus below the focus lens position. In this embodiment, 1V is 1/60 second. The driving of the CMOS sensor will be described with reference to FIG. The left side of FIG. 7 shows an imaging surface and a scanning line. The right shows the charge accumulation time and transfer time for each scan 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 diamond in FIG. 6 represents the charge accumulation of such a CMOS sensor.

  In FIG. 6, the camera microcomputer 116 acquires the TVAF evaluation value EV3 for the charge accumulated in the CMOS sensor during the accumulation time 3 at time T3. In addition, the camera microcomputer 116 obtains the TVAF evaluation value EV5 for the charge accumulated in the CMOS sensor during the accumulation time 5 at time T5. At time T6, the camera microcomputer 116 compares the TVAF evaluation values EV3 and EV5 and moves the vibration center of the focus lens 105 if EV5> EV3, and moves the vibration center of the focus lens 105 if EV5> EV3. do not do. In this way, the camera microcomputer 116 determines the in-focus direction and the in-focus determination.

  Next, processing timing of the camera microcomputer 116 and the lens microcomputer 115 will be described. FIG. 8 is a diagram showing a timing chart of processing of the camera microcomputer 116 and the lens microcomputer 115 in 1V. In FIG. 8, the horizontal axis indicates time. First, immediately after the V synchronization signal is output, communication is performed between the camera microcomputer 116 and the lens microcomputer 115, and the camera microcomputer 116 acquires the focus lens position and target position arrival determination data from the lens microcomputer 115. After acquiring the TVAF evaluation value, the camera microcomputer 116 calculates the target position for minute driving and the driving speed of the focus lens 105 shown in FIG. 6 from the data acquired from the lens microcomputer 115 through communication and the TVAF evaluation value. Thereafter, the camera microcomputer 116 communicates with the lens microcomputer 115 again, and transmits a focus lens drive command (target position, drive speed) and a drive delay time to the lens microcomputer 115. After waiting for the drive delay time, the lens microcomputer 115 performs lens drive processing based on the focus lens drive command to drive the focus lens 105.

  Next, it will be described that the camera microcomputer 116 changes the TVAF control using communication data with the lens microcomputer 115 and the camera microcomputer 116 operates correctly with respect to the delay in driving the focus lens 105. FIG. 9 is a diagram illustrating an example of communication data between the camera microcomputer 116 and the lens microcomputer 115. Communication data from the camera microcomputer 116 to the lens microcomputer 115 includes the focus target position and the driving speed of the focus lens. On the other hand, communication data from the lens microcomputer 115 to the camera microcomputer 116 includes focus lens position and target position arrival determination data. For example, the target position arrival determination is transmitted by H / L of a predetermined signal among signals sent from the lens microcomputer 115 to the camera microcomputer 116. In this case, the camera microcomputer 116 determines whether or not the focus lens 105 can reach the drive target position within a predetermined time by detecting H / L of the predetermined signal. By communicating these data between the camera microcomputer 116 and the lens microcomputer 115, the camera microcomputer 116 determines the drive target position and drive speed of the focus lens 105, and transmits a drive command for the focus lens 105 to the lens microcomputer 115.

  Next, a case where the camera microcomputer 116 determines that the focus lens 105 cannot reach the focus target position received from the camera microcomputer 116 within a predetermined time will be described. In this embodiment, it is assumed that the focus lens 105 is moved during 1 V (1/60 seconds). In this case, the predetermined time corresponds to 1V.

  FIG. 10 shows the elapsed time of the focus lens operation when the movement of the focus lens 105 is not in time for the accumulation time 3 as the first timing. In FIG. 10, the camera microcomputer 116 performs AF control based on the TVAF evaluation value generated from the charge accumulated in the image sensor 106 during the accumulation time 3, 5, 7, 9,. In addition, it is assumed that the focus lens 105 cannot reach the target position during 1 V, and the drive of the focus lens 105 cannot be completed before the charge accumulation for the accumulation time 3. The lens microcomputer 115 drives and controls the focus drive source 112 so as to move the focus lens 105 to the target position received from the camera microcomputer 116, and transmits data indicating that the target position cannot be reached within a predetermined time at communication at time T2. To the camera microcomputer 116. When receiving the data, the camera microcomputer 116 does not use the TVAF evaluation value EV3 (first focus signal) for the charges accumulated in the image sensor 106 during the accumulation time 3, and the accumulation time 4 as the second timing is used. The TVAF evaluation value EV4 (second focus signal) for the charge accumulated in the image sensor 106 during this period is set as the infinite evaluation value. At this time, the camera microcomputer 116 performs control so that the focus lens 105 is stopped during the charge accumulation in the area corresponding to the TVAF frame at the accumulation time 4. The camera microcomputer 116 controls the lens microcomputer 115 so that the next focus lens movement start is after the charge accumulation in the region corresponding to the TVAF frame at the accumulation time 4 ends.

  After the above operation, in FIG. 10, the TVAF evaluation value used for driving control of the focus lens 105 is shifted and generated from the charge accumulated in the image sensor 106 during the accumulation time 6, 8, 10,. TVAF control is performed based on the TVAF evaluation value. At time T7, the camera microcomputer 116 compares the TVAF evaluation values EV4 and EV6 and moves the vibration center if EV6> EV4, and does not move the vibration center unless EV6> EV4. In this way, the camera microcomputer 116 determines the in-focus direction and the in-focus determination.

  As described above, the lens microcomputer 115 sends necessary data to the camera microcomputer 116 with respect to the delay of the focus lens movement, and the camera microcomputer 116 changes the next drive of the focus lens 105 based on the acquired data. Further, the camera microcomputer 116 can correctly acquire the TVAF evaluation value at the timing when the focus lens 105 exists on the infinite side or the close side by changing the TVAF evaluation value referred to for TVAF control.

  In the present embodiment, it has been described that the camera microcomputer 116 sends the data of the focus target position to the lens microcomputer 115. However, the camera microcomputer 116 is not limited to the focus target position, and may be data indicating the movement amount of the focus lens 105. For example, the camera microcomputer 116 may send information about how many pulses the focus driving source 112 drives the focus lens 105 in which direction to the lens microcomputer 115.

  In the present embodiment, the predetermined time is 1 V, but the present invention is not limited to this. The camera microcomputer 116 may set the driving time of the focus lens 105 and transmit it to the lens microcomputer 115.

  In FIG. 10, data indicating that the lens microcomputer 115 cannot reach the target position is sent to the camera microcomputer 116 at time T2, but the lens microcomputer 115 detects that the target position cannot be reached within a predetermined time at an earlier timing. It may be determined and notified to the camera microcomputer 116 before time T2.

  In FIG. 10, after receiving data indicating that the target position cannot be reached from the lens microcomputer 115, the camera microcomputer 116 generates the TVAF evaluation value EV4 generated from the charges accumulated in the image sensor 106 during the accumulation time 4. However, the TVAF evaluation value generated from the charge accumulated in the image sensor 106 in the later accumulation time may be used. In this case, the camera microcomputer 116 controls the lens microcomputer 115 to stop the focus lens 105 during charge accumulation in the area corresponding to the TVAF frame at the accumulation time.

  In the present embodiment, the lens microcomputer 115 transmits data indicating that the focus lens 105 cannot reach the target position when it is determined that the target lens 105 cannot reach the target position within a predetermined time. If the target position can be reached, data indicating that the target position can be reached is sent. By doing so, the camera microcomputer 116 can appropriately determine whether or not the focus lens 105 can reach the target position within a predetermined time, so that more accurate AF control can be realized.

  Next, control of the hill-climbing driving operation will be described with reference to FIG. Step 1101 indicates the start of processing. At Step 1102, the camera microcomputer 116 transmits a focus lens driving command to the lens microcomputer 115 and receives a target position arrival determination for the focus lens position and the driving command from the lens microcomputer 115.

  In Step 1103, the camera microcomputer 116 sets the driving speed of the focus lens 105 in the hill-climbing driving operation. Although not described in detail here, based on the depth of focus, it is general to decrease the driving speed when the depth is shallow and increase the driving speed when the depth is deep.

  In Step 1104, the camera microcomputer 116 determines whether the TVAF evaluation value is smaller than the previous TVAF evaluation value by a predetermined amount. If not smaller, the process proceeds to Step 1105. If smaller, the process proceeds to Step 1110. Here, the predetermined amount is a value determined in consideration of the S / N of the TVAF evaluation value, and is a value not less than the fluctuation range of the TVAF evaluation value when the subject is fixed and the focus lens position is constant. Otherwise, the camera microcomputer 116 cannot perform hill-climbing drive control in the correct direction under the influence of the change in the TVAF evaluation value due to factors other than the change in the focus state.

  In Step 1105, the camera microcomputer 116 determines whether the focus lens 105 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 focus lens 105 has reached the infinite end, the process proceeds to Step 1106. If the focus lens 105 has not reached the infinite end, the process proceeds to Step 1107.

  In Step 1107, the camera microcomputer 116 determines whether or not the focus lens 105 has reached the closest end. The closest end is the position closest to the focus lens stroke determined by design. If the focus lens 105 has reached the close end, the process proceeds to Step 1108. If the focus lens 105 has not reached the close end, the process proceeds to Step 1109.

  In Steps 1106 and 1108, the camera microcomputer 116 sets a flag for storing the inverted end and proceeds to Step 1112 to invert the focus lens 105 in the reverse direction and continue the hill-climbing drive.

  In Step 1109, the camera microcomputer 116 instructs the lens microcomputer 115 to drive the focus lens 105 in the forward direction at the speed determined in Step 1103, and proceeds to Step 1102 to end the current process.

  In Step 1110, if the TVAF evaluation value has not decreased beyond the peak, the process proceeds to Step 1111. If the TVAF evaluation value has decreased beyond the peak, the process proceeds to Step 1113, the camera microcomputer 116 ends the hill-climbing drive, proceeds to Step 1114, ends the process, and shifts to the minute drive operation.

  In Step 1111, the camera microcomputer 116 determines whether the TVAF evaluation value has decreased continuously a predetermined number of times. If the TVAF evaluation value continuously decreases, the process proceeds to Step 1112. If the TVAF evaluation value does not decrease continuously, the process proceeds to Step 1109.

  In Step 1109, the camera microcomputer 116 instructs the lens microcomputer 115 to drive the focus lens 105 in the forward direction at the speed determined in Step 1103, and proceeds to Step 1102 to end the current process.

  In Step 1112, the camera microcomputer 116 instructs the lens microcomputer 115 to drive the focus lens 105 in a reverse direction to the previous time at the speed determined in Step 1103, and proceeds to Step 1102 to end the current process.

  FIG. 12 shows the movement of the focus lens 105 during the hill-climbing driving operation. In A indicated by a solid line, since the TVAF evaluation value decreases beyond the peak, the camera microcomputer 116 determines that there is a focal point during the hill-climbing drive so far, and ends the hill-climbing drive operation. On the other hand, in B shown by the dotted line, since the TVAF evaluation value decreases without a peak, the camera microcomputer 116 determines that the direction is wrong and drives the focus lens 105. Reverse the direction and continue the hill-climbing drive operation.

  As described above, the camera microcomputer 116 controls the camera AF 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.

  Thus, the lens microcomputer 115 sends necessary data to the camera microcomputer 116 in response to the drive delay of the focus lens 105, and the camera microcomputer 116 changes the next drive of the focus lens 105 based on the acquired data. . Further, the camera microcomputer 116 can refer to the TVAF evaluation value at the timing when the focus lens 105 stops on the infinite side or the closest side by changing the TVAF evaluation value referred to for TVAF control. It becomes possible to correctly determine the focal direction.

(Example 2)
As described above, in the first embodiment, when the focus lens 105 cannot reach the target position within a predetermined time, the lens microcomputer 115 sends data indicating that the focus lens 105 cannot reach the camera microcomputer 116.

  In this embodiment, the camera microcomputer 116 determines that the focus lens 105 cannot reach the target position within a predetermined time based on the focus lens position data received from the lens microcomputer 115. The focus lens drive control of this embodiment will be described with reference to FIG.

  In FIG. 10, the camera microcomputer 116 determines whether or not the drive of the focus lens 105 can reach the target position within a predetermined time based on the focus lens position received from the lens microcomputer 115 at time T1. When the camera microcomputer 116 determines that the drive of the focus lens 105 cannot reach the target position within a predetermined time, the TV AF frame at the accumulation time 4 after the focus lens 105 reaches the target position, as in the first embodiment. The lens microcomputer 115 is controlled to stop the focus lens 105 during the charge accumulation in the area corresponding to. Further, the camera microcomputer 116 performs TVAF control based on the TVAF evaluation value EV4 generated from the charges accumulated in the image sensor 106 during the accumulation time 4.

  Note that the timing of receiving focus lens position information for determining whether the drive of the focus lens 105 can reach the target position within a predetermined time is not limited to the time T1. Alternatively, the camera microcomputer 116 may acquire the focus lens position at a predetermined timing from 1 V in the lens microcomputer 115.

  Also in this embodiment, the camera microcomputer 116 may perform TVAF control using the TVAF evaluation value generated from the charge accumulated in the image sensor 106 during the accumulation time after the accumulation time 4. In this case, the camera microcomputer 116 instructs the lens microcomputer 115 to stop the focus lens 105 during the charge accumulation in the area corresponding to the TVAF frame at the accumulation time.

  In this way, if the camera microcomputer 116 can determine that the focus lens 105 cannot reach the target position within a predetermined time based on the focus lens position data, the lens microcomputer 115 cannot reach the target position. The present invention can be implemented without sending the data shown.

  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 107 Amplifier 108 Camera signal processing circuit 112 Focus drive source 113 TVAF gate 114 TVAF signal processing circuit 115 Lens microcomputer 116 Camera microcomputer 117 Lens unit 118 Camera unit

Claims (7)

A lens unit with an imaging optical system including a focus lens can be attached and detached.
Imaging means for detecting light passing through the imaging optical system and accumulating charges, transferring the accumulated charges to generate an imaging signal; and
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;
An imaging apparatus comprising: a control unit that determines a movement amount of the focus lens based on the focus signal extracted by the extraction unit, and transmits information of the movement amount to the lens unit;
The control means receives from the lens unit information indicating whether or not the focus lens can move within a predetermined time based on the movement amount transmitted to the lens unit, and the focus lens determines the movement amount within the predetermined time. When the information indicating that it is movable is received, on the basis of the first focus signal extracted from the imaging signal corresponding to the electric charge accumulated in the focus detection area at the first timing, Determining the amount of movement, and when receiving information indicating that the focus lens is not movable within the predetermined time, without using the first focus signal, after the movement of the focus lens, Extracted from the imaging signal corresponding to the charge accumulated in the focus detection area at the second timing when the focus lens is stopped Based on the second focus signal, the imaging apparatus characterized by determining a next movement of the focus lens.   The imaging apparatus according to claim 1, wherein the predetermined time is set by the control unit and notified to the lens unit.   The control means receives position information of the focus lens from the lens unit, and determines whether or not the focus lens can move within a predetermined time based on the position information. The imaging apparatus according to claim 1 or 2. An imaging unit that detects light passing through the imaging optical system, accumulates charges, transfers the accumulated charges to generate an imaging signal, and determines focus adjustment control based on a focus signal extracted from the imaging signal It can be attached to an imaging device equipped with a control means,
The imaging optical system including a focus lens;
Focus drive means for driving the focus lens;
A lens unit having a lens-side control unit that receives information for focus adjustment from the control unit of the mounted imaging apparatus and controls the driving of the focus driving unit based on the information;
The lens-side control means receives information on the amount of movement of the focus lens from the control means, and notifies the control means of whether or not the focus lens can move within a predetermined time. Lens unit to be used.   The lens unit according to claim 4, wherein the lens-side control unit transmits position information of the focus lens to the control unit.   The lens-side control means stops the movement of the focus lens after the focus lens has moved the amount of movement received from the control means, and charge accumulation corresponding to the focus detection area in the imaging surface of the imaging means 6. The lens unit according to claim 4, wherein the focus driving unit is controlled to stop the focus lens until completion. An imaging unit that detects light passing through the imaging optical system, accumulates charges, transfers the accumulated charges to generate an imaging signal, and determines focus adjustment control based on a focus signal extracted from the imaging signal It can be attached to an imaging device equipped with a control means,
The imaging optical system including a focus lens;
Focus drive means for driving the focus lens;
A lens unit having a lens-side control unit that receives information for focus adjustment from the control unit of the mounted imaging apparatus and controls the driving of the focus driving unit based on the information;
The lens-side control means transmits a predetermined signal to the control means, and the predetermined signal is a signal for changing a focus signal used by the control means for focus adjustment control according to the signal level. Lens unit.

Images