JP2016090982A - Automatic focusing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic focusing unit that allows a desired scan position to be included within a scan range even when a zoom lens is halted at a position different from a set position or when the relationship between an in-focus distance and a position of a focus lens is varied because of a vibration, drop, or passage of time.SOLUTION: A moving range of a focus lens is designated in consideration of an error in halting when a zoom lens is driven to a set position. Based on a deviation of a halt position, which is derived from a manufacturing tolerance or precision in detection by zoom lens position detection means, from a position at which the zoom lens is halted when driven to the set position, the position of the focus lens necessary to focus on an object located at a desired distance on an infinitely far side or near side is worked out. The range within which the focus lens is moved to sample an AF evaluation value is designated so that the range includes the position.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an automatic focus adjustment device, and more particularly to an automatic focus adjustment device that performs focus adjustment using an image signal acquired by an image sensor that photoelectrically converts a subject image formed by an imaging optical system.

  An example of a conventional method for setting a range for driving a focus adjusting means for searching for a focus position is disclosed in Patent Document 1 as follows.

  In an autofocus device that performs imaging by controlling a zoom lens and a focus lens, an imaging means for imaging a subject to obtain a digital video signal, and an AF evaluation value from a luminance signal contained in the digital video signal obtained by the imaging means The sampling means for sampling the AF evaluation value obtained by the evaluation means while moving the position of the focus lens, and the sampling means according to the position of the zoom lens and the position of the focus lens. Focus amount for driving and controlling the focus lens to the in-focus position based on the sampling result of the sampling means accompanying the change of the movement amount changing means, and a movement amount changing means for changing the movement amount of the focus lens at the time of each sampling And an AF evaluation by the sampling means. It characterized in that a position of the focus lens starts sampling value with a sampling start position changing means for changing in accordance with the position of the zoom lens.

Japanese Patent No. 3866844

  However, in Patent Document 1, the position of the focus lens that starts sampling of the AF evaluation value is changed according to the position of the zoom lens system, and an efficient operating range of the focus lens suitable for the zoom position is set. Therefore, the AF execution time can be shortened compared to the case where the zoom lens system is not changed according to the position of the zoom lens system, but when the zoom lens stops at a position different from the set position, or due to vibration, drop, time, etc. It cannot cope with a change in the relationship between the focus distance and the focus lens position.

  Specifically, AF evaluation value sampling is started because the zoom lens has stopped at a position different from the set position, or because the focus distance and focus lens position change due to vibration, drop, or time. When the position of the focus lens to be used is different from a desired sampling start position (for example, a position corresponding to infinity with a margin added), the desired sampling position is not included in the operation range, and the subject at that distance is focused. I can't.

  The present invention allows the desired scan position to be scanned even when the zoom lens stops at a position different from the set position, or when the relationship between the focus distance and the position of the focus lens changes due to vibration, dropping, or aging. An object of the present invention is to provide an automatic focus adjustment device that is included in the range.

  In order to achieve the above object, the automatic focus adjustment apparatus of the present invention sets the operating range of the focus lens in consideration of a stop error when the zoom lens is driven to a set position. That is, in order to focus on a subject at a desired distance on the infinity side or the closest side from the deviation of the stop position obtained from the manufacturing tolerance or the detection accuracy of the zoom lens position detection means when the zoom lens is stopped at the set position. A necessary focus lens position is determined, and an AF evaluation value sampling range is set so as to include the position.

  Further, when the relationship between the focus distance and the position of the focus lens changes due to vibration, drop, aging, etc., a desired sampling start position (for example, from the AF evaluation value acquired in the sampling range set as described above, for example, The position corresponding to infinity with a margin added), and setting that position as the sampling start position when sampling the next AF evaluation value (for example, the position corresponding to the infinity equivalent with a margin) Features.

  According to the automatic focus adjustment apparatus of the present invention, the operation range of the focus lens is set in consideration of the stop error when the zoom lens is driven to the set position, so that it is desired even when the zoom lens does not stop at the set position. It is possible to focus on a subject at a distance of.

  Further, by estimating a desired sampling start position (for example, a position corresponding to infinity with a margin) from the acquired AF evaluation value, the focus distance and the position of the focus lens can be determined by vibration, drop, time, etc. Even when the relationship changes, it is possible to focus on a subject at a desired distance in the subsequent AF operation.

Block diagram of Examples 1-4 Explanatory drawing of operation procedure of Examples 1-4 Operation explanatory diagram of scan AF processing of Embodiment 1 Operation explanatory diagram of processing for obtaining a correction amount according to the first embodiment The figure explaining the relationship with the zoom position of the focus cam The figure which shows an example when AF evaluation value stops climbing to the far side Diagram showing the relationship between the design value of the infinity cam and the actual value Operation explanatory diagram of processing for obtaining the correction amount of the fourth embodiment

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Example 1]
FIG. 1 shows a block diagram of an embodiment of the present invention. Reference numeral 1 denotes an image pickup device, 2 denotes a zoom lens group, 3 denotes a focus lens group, 4 denotes a light amount adjusting means for controlling the amount of light beam transmitted through a photographing optical system including the zoom lens group 2, the focus lens group 3, and the like. A diaphragm 31, a zoom lens group 2, a focus lens group 3, a diaphragm 4, and the like, is a photographing lens barrel, and 5 is a solid-state imaging device that forms a subject image that has passed through the photographing optical system and photoelectrically converts the subject image. (Hereinafter referred to as sensor) 6 is an image pickup circuit that receives the electrical signal photoelectrically converted by the sensor 5 and performs various image processing to generate a predetermined image signal.

  Reference numeral 7 denotes an A / D conversion circuit that converts an analog image signal generated by the imaging circuit 6 into a digital image signal. Reference numeral 8 denotes a buffer that receives the output of the A / D conversion circuit 7 and temporarily stores the image signal. A memory (VRAM) such as a memory, 9 reads out an image signal stored in the VRAM 8, converts it into an analog signal, and converts it into an image signal in a form suitable for reproduction output, and 10 denotes this image An image display device (hereinafter referred to as LCD) such as a liquid crystal display device (LCD) for displaying signals, and a storage memory 12 for storing image data such as a semiconductor memory.

  11 is a compression circuit that performs compression processing and encoding processing of image data to read out an image signal temporarily stored in the VRAM 8 and put it into a form suitable for storage in the storage memory 12, and an image stored in the storage memory 12. A compression / decompression circuit 13 including a decompression circuit for performing a decoding process and a decompression process for making the data in an optimum form for reproduction display and the like, 13 is automatically exposed in response to an output from the A / D conversion circuit 7 (AE) an AE processing circuit that performs processing, 14 is a scan AF processing circuit that receives an output from the A / D conversion circuit 7 and generates an AF evaluation value for performing automatic focus adjustment (AF) processing, and 15 is an imaging device This is a CPU with a built-in memory for controlling the above.

  16 is a timing generator (hereinafter referred to as TG) that generates a predetermined timing signal, 17 is a sensor driver, 21 is a diaphragm drive motor that drives the diaphragm 4, 18 is a first motor drive circuit that controls the drive of the diaphragm drive motor 21, and 22 is A focus drive motor for driving the focus lens group 3, a second motor drive circuit 19 for driving and controlling the focus drive motor 22, a zoom drive motor for driving the zoom lens group 2, and a drive control for the zoom drive motor 23. Third motor drive circuit, 24 is an operation switch composed of various switch groups, 25 is an electrically rewritable read-out in which programs for performing various controls and data used for performing various operations are stored in advance It is an EEPROM which is a dedicated memory.

  26 is a battery, 28 is a strobe light emitting unit, 27 is a switching circuit for controlling flash light emission of the strobe light emitting unit 28, 29 is a display element such as an LED for displaying a warning, etc. 30 is for voice guidance or warning A speaker 33 is an AF auxiliary light composed of a light source such as an LED, which is an illuminating means for illuminating all or a part of the subject when obtaining an AF evaluation value, and 32 is an AF auxiliary light for driving the AF auxiliary light 33. An optical drive circuit, 35 is a shake detection sensor that detects camera shake, 34 is a shake detection circuit that processes a signal from the shake detection sensor 35, and 36 is a face position on the screen in response to an output from the A / D conversion circuit 7. And a face detection circuit for detecting the size of the face.

  The storage memory, which is a storage medium for image data or the like, is a fixed semiconductor memory such as a flash memory, or a semiconductor such as a card type flash memory that has a card shape or stick shape and is detachable from the device. In addition to the memory, various forms such as a magnetic storage medium such as a hard disk or a floppy disk are applied.

  The operation switch 24 includes a main power switch for starting the imaging apparatus 1 to supply power, a release switch for starting a photographing operation (storage operation), a reproducing switch for starting a reproducing operation, and a photographing optical system. There are a zoom switch for moving the zoom lens group 2 to perform zooming, an optical viewfinder (OVF) electronic viewfinder (EVF) changeover switch, and the like.

  The release switch then performs a first stroke (hereinafter referred to as SW1) for generating an instruction signal for starting AE processing and AF processing performed prior to the photographing operation and a second stroke (hereinafter referred to as SW2) for generating an instruction signal for starting an actual exposure operation. And a two-stage switch.

  The operation of this embodiment configured as described above will be described below. First, the light flux of the subject that has passed through the photographing lens barrel 31 of the image pickup apparatus 1 is adjusted on the light amount by the diaphragm unit 4 and then imaged on the light receiving surface of the sensor 5. This subject image is converted into an electrical signal by photoelectric conversion processing by the sensor 5 and output to the imaging circuit 6. In the imaging circuit 6, various signal processing is performed on the input signal, and a predetermined image signal is generated. The image signal is output to the A / D conversion circuit 7 and converted into a digital signal (image data), and then temporarily stored in the VRAM 8. The image data stored in the VRAM 8 is output to the D / A conversion circuit 9, converted into an analog signal, converted into an image signal in a form suitable for display, and then displayed as an image on the LCD.

  On the other hand, the image data stored in the VRAM 8 is also output to the compression / decompression circuit 11. After compression processing is performed by the compression circuit in the compression / decompression circuit 11, it is converted into image data in a form suitable for storage and stored in the storage memory 12.

  For example, when a reproduction switch (not shown) of the operation switches 24 is operated and turned on, a reproduction operation is started. Then, the image data stored in a compressed form in the storage memory 12 is output to the compression / expansion circuit 11, subjected to decoding processing, expansion processing, etc. in the expansion circuit, and then output to the VRAM 8 and temporarily stored. The Further, the image data is output to the D / A conversion circuit 9, converted into an analog signal, converted into an image signal in a form suitable for display, and then displayed on the LCD 10 as an image.

  On the other hand, the image data digitized by the A / D conversion circuit 7 is also output to the AE processing circuit 13, the scan AF processing circuit 14, and the face detection circuit 36 separately from the VRAM 8 described above. First, the AE processing circuit 13 receives the input digital image signal and performs arithmetic processing such as cumulative addition on the luminance value of the image data for one screen. Thereby, the AE evaluation value corresponding to the brightness of the subject is calculated. This AE evaluation value is output to the CPU 15.

  The scan AF processing circuit 14 receives the input digital image signal, extracts high-frequency components of the image data through a high-pass filter (HPF) or the like, and performs arithmetic processing such as cumulative addition, AF evaluation value signals corresponding to the contour component amounts and the like are calculated. Specifically, in the scan AF process, a high-frequency component of image data corresponding to a partial area of the screen designated as an AF area is extracted through a high-pass filter (HPF) or the like, and an arithmetic process such as cumulative addition is performed.

  Thereby, an AF evaluation value signal corresponding to the contour component amount on the high frequency side and the like is calculated. When this AF area is one place in the central part or any part on the screen, or in the central part or any part on the screen and a plurality of adjacent parts, or in a plurality of places distributed discretely and so on.

  As described above, the scan AF processing circuit 14 plays a role of high-frequency component detection means for detecting a predetermined high-frequency component from the image signal generated by the sensor 5 in the process of performing the AF processing. The face detection circuit 36 receives the input digital image signal, searches the image for a part characterizing the face such as eyes and eyebrows, and obtains the position of the person's face on the image. Further, the size and inclination of the face are obtained from the positional relationship such as the interval between the parts characterizing the face.

  On the other hand, a predetermined timing signal is output from the TG 16 to the CPU 15, the imaging circuit 6, and the sensor driver 17, and the CPU 15 performs various controls in synchronization with this timing signal. The imaging circuit 6 receives the timing signal from the TG 16 and performs various image processing such as separation of color signals in synchronization with the timing signal. Further, the sensor driver 17 receives the timing signal of the TG 16 and drives the sensor 5 in synchronization therewith.

  Further, the CPU 15 controls the first motor driving circuit 18, the second motor driving circuit 19, and the third motor driving circuit 20, respectively, so that the diaphragm 4 via the diaphragm driving motor 21, the focus driving motor 22, and the zoom driving motor 23 is controlled. The focus lens group 3 and the zoom lens group 2 are driven and controlled.

  That is, the CPU 15 controls the first motor drive circuit 18 based on the AE evaluation value calculated in the AE processing circuit 13 to drive the aperture drive motor 21 and adjust the aperture amount of the aperture 4 so as to be appropriate. I do. Further, the CPU 15 controls the second motor drive circuit 19 based on the AF evaluation value signal calculated by the scan AF processing circuit 14 to drive the focus drive motor 22 and performs AF control to move the focus lens group 3 to the in-focus position. . When a zoom switch (not shown) among the operation switches 24 is operated, the CPU 15 moves the zoom lens group 2 by controlling the third motor drive circuit 20 and driving the zoom motor 23 in response to the operation. Then, the zooming operation of the photographing optical system is performed.

  Next, the actual photographing operation of the imaging apparatus will be described with reference to the flowchart shown in FIG. In the description of the present invention, the operation of acquiring the AF evaluation value while driving the focus lens group 3 to a predetermined position is scanned, the interval of the position of the focus lens for acquiring the AF evaluation value is the scan interval, and the AF evaluation value is acquired. The position to be scanned is the scan point, the number of AF evaluation values to be acquired is the number of scan points, the range to acquire the AF evaluation value is the scan range, and the area for acquiring the image signal for detecting the in-focus position is the AF frame To do.

  When the main power switch of the imaging apparatus 1 is in the ON state and the operation mode of the imaging apparatus is in the shooting (recording) mode, the shooting process sequence is executed.

  First, in step S1, the CPU 15 displays an image formed on the sensor 5 through the photographing lens barrel 31 as an image on the LCD. That is, the subject image formed on the sensor 5 is photoelectrically converted by the sensor 5 and converted into an electrical signal, and then output to the imaging circuit 6. Therefore, various signal processing is performed on the input signal to generate a predetermined image signal, which is then output to the A / D conversion circuit 7 to be converted into a digital signal (image data) and temporarily stored in the VRAM 8. The The image data stored in the VRAM 8 is output to the D / A conversion circuit 9, converted into an analog signal, converted into an image signal in a form suitable for display, and then displayed as an image on the LCD.

  Next, in step S2, the state of the release switch is confirmed. When the photographer operates the release switch and the CPU 15 confirms that SW1 (first stroke of the release switch) has been turned on, the process proceeds to the next step S3, and normal AE processing is executed. Subsequently, in step S4, a plurality of AF evaluation values are acquired, and a scan AF process for detecting the in-focus position from the result is performed. Details of this processing will be described later.

  If the AF evaluation value obtained in step S4 is sufficiently reliable, AFOK display is performed in step S5. This is performed by turning on the display element 29 or the like, and at the same time, processing such as displaying a green frame on the LCD. If the reliability of all AF evaluation value signals is low in step S4, the focus position is not detected and the process proceeds to step S5 to display AFNG. This is performed by, for example, blinking the display element 29, and simultaneously performing processing such as displaying a yellow frame on the LCD.

  In step S6, the CPU 15 confirms SW2 (second stroke of the release switch). If SW2 is on, the CPU 15 proceeds to step S7 and executes actual exposure processing. Here, the concept of the scan AF process for detecting the in-focus position in step S4 will be described with reference to FIG. The scan AF is performed by obtaining the position of the focus lens group 3 that maximizes the high-frequency component output from the image signal generated by the sensor 5.

  The CPU 15 controls the focus drive motor 22 via the second motor drive circuit 19 that controls the drive of the focus drive motor 22, and the scan start position (the focus lens group 3 on the side farther than the position corresponding to infinity by a predetermined amount beyond infinity). Drive from a position ("A" in FIG. 3) to a scan end position set in each imaging mode (for example, a position closer to the closer side than the position corresponding to the closest distance ("B" in FIG. 3)). To do. The output (AF evaluation value signal) of the scan AF processing circuit is acquired while being driven, and the position where the output becomes maximum from the AF evaluation value signal acquired when the driving of the focus lens group 3 is completed (“ C ”).

  The acquisition of the output of the AF processing circuit is not performed at all the stop positions of the focus lens group 3 but at predetermined steps for speeding up the scan AF. In this case, the AF evaluation value signal may be acquired at points a1, a2, and a3 shown in FIG. In such a case, the in-focus position C is obtained by calculation from the point at which the AF evaluation value signal becomes the maximum value and the points before and after the point. The process for obtaining the position where the AF evaluation value signal becomes the maximum value (focus position) is performed only when the reliability of the AF evaluation value is sufficient. The method for evaluating the reliability of the AF evaluation value signal is described in Patent Document Special Registration 04235422 and Special Registration 04185741, and will not be described here.

  Here, a method of setting the scan range of the scan AF process in step S4 will be described. The position corresponding to the focus lens group 3 corresponding to infinity (“A” in FIG. 3) and the position corresponding to the closest distance set in each photographing mode (“B” in FIG. 3) are usually acquired in the manufacturing process. Use the value as it is. In the manufacturing process, a measurement chart is placed at a predetermined distance, and the position of the focus lens group 3 when the chart is focused is acquired and recorded in the EEPROM 25. A plurality of the predetermined distances may be set, or may be set to one for shortening the measurement time. In the case of only one distance, the position of the focus lens group 3 at another distance is obtained with the design value.

Further, when measurement is performed at a plurality of distances, it is obtained by interpolation extrapolation from the position of the focus lens group 3 obtained at the measurement distances. If the in-focus position is measured at two distances (for example, an equivalent distance at infinity and 1 m), the position of the focus lens group 3 other than the measurement distance is obtained by the following equation. When the position of the focus lens group 3 at the measurement / distance L _F · L _N is P _F · P _N , the position P of the focus lens group 3 at the distance L is P = (P _N −P _F ) · L _F · L _N / (L _F -L _N ) / L + (P _F L _F -P _N L _N ) / (L _F -L _N )
Is required.

  Further, at all zoom positions set in the variable magnification optical system, there is no need to measure the position of the focus lens group 3 when focused on the chart, and the zoom positions are measured so as to satisfy the required measurement accuracy. What is necessary is just to obtain | require by interpolation calculation from the position of the focus lens group 3 in FIG.

  Problems with the scan range thus obtained include zoom stop error, camera posture difference, vibration, drop, and other changes over time (for example, changes in the distance between the lenses constituting the lens barrel 31 due to expansion and contraction of members). Thus, the scan start position / end position is different from the prospective position, and a scan range not including the desired distance range is set. For example, if the position corresponding to infinity of the focus lens group 3 shifts to a position on the ultra-infinity side from a predetermined amount due to any of the above factors, the position corresponding to infinity is not included in the scan range and exists at infinity. Cannot focus on the subject.

  Similarly, if the focus lens group 3 is shifted to a position closer to the closest distance than a predetermined amount due to some of the above factors, the subject located at the closest distance set in each photographing mode I can't focus on it.

  Therefore, the processing shown in the operation procedure shown in FIG. 4 is performed. First, in step S401, a scan range is set. The CPU 15 detects the position of the zoom lens group 2 set as a result of the zooming operation. If there is a sensor that detects the movement position of the zoom lens group 2, read the output of that sensor. The position of the zoom lens group 2 is detected. When there is no sensor, the position controlled by the CPU 15 is set as the position of the zoom lens group 2.

  Next, an adjustment value adj (z, ∞) corresponding to infinity corresponding to the position of the zoom lens group 2 (the focus lens corresponding to the position corresponding to infinity of the focus lens group 3 acquired in the manufacturing process) (Position of group 3) and position adjustment value adj (z, Near) corresponding to the closest distance (corresponding to a position corresponding to the closest distance set in each photographing mode of the focus lens group 3 acquired in the manufacturing process) The position of the focus lens group 3 to be read) is read from the EEPROM. This value is corrected in consideration of stop error, camera posture difference, vibration, drop, and other changes over time.

The position corresponding to infinity Pos (z, ∞) and the position Pos (Nea) corresponding to the closest distance for determining the scanning range are corrected according to the following equations.
Pos (z, ∞) = adj (z, ∞)-Err (z, ∞) + Angl (z)-Corr (z, ∞) (Formula 1-1)
Pos (z, Near) = adj (z, Near) + Err (z, Near) + Angl (z) (Formula 1-2)
Here, Err (z, ∞) and Err (z, Near) are correction amounts due to the displacement amount of the focus lens group 3 when the zoom stop position shifts, and Angl (z) is an adjustment in the manufacturing process. Corr (z, ∞) is the correction amount due to vibration, drop, and other changes over time, Err (z, ∞) ・ Angl (z ) ・ Err (z, Near) is a value determined by the time of manufacture based on the design value or measured value, and Corr (z, ∞) is a value determined based on the value acquired in actual use.

  As shown in FIG. 5, the position of the focus lens group 3 at the time of focusing on infinity / close distance varies depending on each zoom position. In FIG. 5, the horizontal axis represents the position of the zoom lens group 2, and the vertical axis represents the position of the focus lens group 3. Curves written as ∞ cam and close-up cam indicate the position of the focus lens group 3 when the zoom lens group 2 is focused at infinity and close-up. For example, this indicates that the focus lens position that focuses in close proximity at the zoom position Zp is Fnp, and the focus lens position that focuses at infinity is Fip.

  At the zoom lens position Zpo, the position adjustment value adj (z, ∞) corresponding to infinity corresponding to the position of the zoom lens group 2 and the position adjustment value adj (z, Near) corresponding to the closest distance are obtained. If an attempt is made, the stop position of the zoom lens group 2 at the time of actual adjustment value acquisition may exist between Zpo− and Zpo + due to manufacturing tolerances specified in the design.

  If the adjustment at the zoom lens position Zpo was performed at the zoom lens position Zpo + and the zoom lens position was controlled to Zpo at the time of shooting, but actually stopped at Zpo−, it was acquired at the zoom lens position Zpo +. In the scan range determined by the adjustment value, the position corresponding to infinity of the focus lens group 3 is not included in the scan range, and there is a possibility that the subject existing at infinity cannot be focused. Therefore, the difference in position of the focus lens group 3 that focuses on a position corresponding to infinity when the stop position of the zoom lens group 2 is Zpo− and Zpo + is obtained as the zoom stop position at the position of the zoom lens group 2. The amount of correction Err (z, ∞) at the infinity position caused by the shift of.

  Similarly, the difference in the position of the focus lens group 3 that focuses on the closest position when the stop position of the zoom lens group 2 is Zpo− and Zpo + is referred to as the shift of the zoom stop position at the position of the zoom lens group 2. The correction amount Err (z, Near) of the close position that is caused is assumed. Angl (z) is a correction amount due to the difference in camera posture between when the adjustment value is acquired and when it is used in the manufacturing process, and has a value for each set position of the zoom lens group 2. When the posture of the camera is different at the time of activation and at the time of shooting, the position of the focus lens group 3 at the time of focusing is generally different. This is because there is a backlash in the structure of the focus lens group 3, and the actual stop position differs even if the same amount of the focus lens group 3 is driven due to the influence of gravity.

  At the time of adjustment, the camera is installed horizontally and activated in that state to obtain adjustment values adj (z, ∞) and adj (z, Near). However, at the time of shooting, I don't know in what state it will be activated. In addition, the orientation of the camera may change after startup. Therefore, for the following six combinations, the shift amount of the focus lens group 3 at the time of activation and photographing is measured in advance and recorded in the EEPROM 25.

Start Shooting Horizontal Upward Horizontal Downward Upward Horizontal Upward Downward Horizontal Downward Upward In step S401, the orientation of the camera at the time of startup recorded at the time of startup and the direction of the camera at the time of scan AF (step S4) are compared, and the same If it is for the camera, zero is referred to. If it is different, the value recorded in the EEPROM 25 is referred to. The direction of the camera is calculated from the output of the shake detection sensor. Corr (z, ∞) is a correction amount due to vibration, drop, or other changes over time, and Corr (z, ∞) is a value determined based on the value acquired during actual use. Although this method will be described later, the initial value is zero. Using the correction amount obtained in this way, the position of the focus lens group 3 corresponding to the corrected infinity / close distance is obtained from (Equation 1-1) and (Equation 1-2).

  The scan start position is a position on the very infinite side from Pos (z, ∞) by the scan interval, and the scan end position is a position closer to the scan interval than Pos (z, Near). The reason why a margin for the scan interval is provided is to ensure that the AF evaluation value peak exists for an object at infinity and close distance. By obtaining an AF evaluation value that is one scan more than the position of the focus lens group 3 when focusing at infinity / closest distance, an AF evaluation value lower than the in-focus position can be obtained on both sides of the position. it can. However, the obtained scan start position and scan end position are limited within a range in which the driving range and optical performance of the focus lens group 3 are guaranteed.

  Next, in step S402, scanning is performed from the scan start position to the end position, and a plurality of AF evaluation values are acquired. In step S403, the reliability of the AF evaluation value is evaluated by the method described in Patent Document Special Registration 04235422 or Special Registration 04185741. As a result, when it is determined that there is no reliability, the process proceeds from step S <b> 404 to S <b> 410, and it is determined that it is out of focus.

If it is determined that there is reliability, the process proceeds to step S405, and it is determined whether or not the AF evaluation value has stopped climbing to the near side. This is performed by comparing the values of the nearest four points among the acquired AF evaluation values. For example, when the four AF evaluation values are d [n], d [n-1], d [n-2], d [n-3] from the closest side.
d [n]> = d [n-1]> = d [n-2]> = d [n-3] (Formula 2)
And
d [n]> d [n-2]
And
d [n-1]> d [n-3]
If so, it is determined that the near side climb has stopped.

  If it is determined that the near-side climbing has stopped, the process proceeds from step S <b> 404 to S <b> 410 and is determined to be out of focus. If it is not determined that the near-side climb has stopped, in step S406, it is determined whether or not the AF evaluation value has stopped climbing to the far side by a method similar to the determination of the near-side climb stop. If it is determined that the far side climb is not stopped, the process proceeds to step S420.

  When the far side stop is stopped, the process proceeds to S407, and processing for obtaining a correction amount Corr (z, ∞) due to vibration, fall, and other changes with time of the adjustment value adj (z, ∞) is performed. The reason why the correction amount calculation is not performed when the near-side climbing stops is that there is a possibility that AF is being performed on a subject closer to it.

  FIG. 6 shows an example when the AF evaluation value stops climbing to the far side. Taking this as an example, the method for obtaining the correction value performed in step S407 will be described. As shown in Fig. 6, the scan starts from the position of the adjustment value adj (z, ∞) on the very infinite side for one scan interval, Pos [0], Pos [1] (= adj (z, ∞)), Assume that the AF evaluation value obtained by Pos [2]... Is as shown in FIG. FIG. 6 illustrates a case where the correction amounts Err (z, ∞) and Angl (z) are zero in order to avoid complication of the drawing.

As shown in FIG. 6, the position of the focus lens group 3 at which the AF evaluation value is at a peak is located on the ultra-infinity side for one scan or more from pos (z, ∞). The condition of the result (Formula 2) is satisfied and it is determined that the far-side climbing has stopped. If the AF evaluation values at Pos [0], Pos [1], Pos [2] are d [0], d [1], d [2] (indicated by black circles in FIG. 6), the calculation is performed. The position Pos [Peak] of the focus lens group 3 at which the AF evaluation value peaks is
Pos [Peak] = Pos [1] + (d [0]-d [2]) * (Pos [1]-Pos [0]) / (d [0]-d [1]) / 2
(Formula 3)
It becomes.

  If the obtained peak position is on the far infinity side from Pos (z, ∞) as indicated by the white circle shown in FIG. 6, the correction amount Corr (z, ∞) for correcting the next scan start position. The process for obtaining is performed. First, it is determined whether it is appropriate to obtain the correction amount. This is performed by determining whether the executed scan is highly likely to be performed on a subject at infinity or whether the reliability of the AF evaluation value signal is sufficient. The reliability evaluation performed in step S403 is for obtaining the in-focus position, and higher reliability is required here.

  First, the white balance coefficient or the color temperature of the light source is checked to determine whether or not it is a value close to sunlight. Although there is an artificial light source called “artificial sun” having a color temperature close to that of sunlight, it can be said that the probability of outdoor shooting is high if sunlight is detected in general shooting. When the color temperature of the light source at the time of shooting is significantly different from that of sunlight and the possibility of outdoor shooting is low, it is determined that the reliability is low.

  Next, the level of the AF rating signal is evaluated. A maximum value and a minimum value of AF evaluation values acquired at a plurality of scan points are obtained, and it is checked whether the difference is equal to or greater than a predetermined value. If it is less than the predetermined value, it is determined that the reliability is low. Note that this predetermined value is larger than that in step S403. Then, the contrast of the original signal for obtaining the AF evaluation value signal is evaluated. A maximum value and a minimum value in an area for obtaining an AF evaluation value of each of image signals acquired at a plurality of scan points are obtained, and a difference between them is obtained. Further, it is checked whether the maximum value of the differences obtained in a plurality of images is equal to or greater than a predetermined value. If it is less than the predetermined value, it is determined that the reliability is low.

  Further, the subject luminance at the time of obtaining the AF evaluation value is obtained, and if the luminance is less than a predetermined value, it is determined that the reliability is low. This is because in the case of shooting under low illuminance, illumination or the like may be used as a subject, and in this case, the reliability of the AF evaluation value may be low due to signal saturation.

  Finally, the temperature and humidity at the time of AF evaluation value acquisition are examined. If the temperature or humidity is outside the predetermined range, it is determined that the reliability is low. This is because in the case of high temperature and low temperature, the position of the focus lens group 3 that temporarily focuses on a subject at infinity may change due to expansion and contraction of the members constituting the lens barrel 31. Similarly, in the case of high humidity and low humidity, there is a possibility that the position of the focus lens group 3 that temporarily focuses on an object at infinity may be changed by deformation of the members constituting the lens barrel 31. . If all the conditions are satisfied and it is determined that there is reliability, the position obtained by (Equation 3) is set as the in-focus position.

If this in-focus position is Pos (z, ∞) outside the scanning range, the correction amount Corr (z, ∞) is changed. Since the in-focus position for an infinite object is the peak position obtained in (Equation 3) or the focus lens position on the ultra-infinity side from that position, it is ultra-infinite by the scan interval from the position obtained in (Equation 3). The correction amount Corr (z, ∞) due to vibration, drop, and other changes over time is set so that the position on the side is the scan start position.
Corr (z, ∞) = adj (z, ∞)-Err (z, ∞) + Angl (z)-Pos [Peak]
Ask and record.

  If this in-focus position is Pos (z, ∞), which is closer to infinity, the correction amount Corr (z, ∞) can be changed. The focus position of an object at infinity may be different from Pos (z, ∞) due to errors in determining the position, so here the scan range correction apparently due to changes over time Is corrected only when it is outside the scan range where it is considered necessary. If there is a peak closer to Pos (z, ∞) than the position obtained in (Equation 3), there is no need to change the scan start position, so the correction amount Corr caused by vibration, drop, or other changes over time (Z, ∞) is not changed.

  Next, the process proceeds to step S408, where the drive position of the focus lens group 3 is obtained and driven to that position. The drive position is Pos [Peak] obtained by (Equation 3). In step S409, it is determined whether or not the drive position of the focus lens group 3 is within the scan range. If the drive position is within the scan range, the process proceeds to step S421, and focus display is performed in step S5 in FIG. If it is out of the scan range, the process proceeds to step S410, and the out-of-focus display is performed in step S5 in FIG.

  If it is determined that the AF evaluation value is reliable and the near side climb is not stopped and the far side climb is not stopped, the process proceeds from step S408 to step S420 as described above. In this case, since the peak of the AF evaluation value exists, the in-focus position can be obtained reliably. Therefore, the position obtained by (Equation 3) is set as the in-focus position, and the focus lens group 3 is driven to that position. Thereafter, as step S421 in-focus determination, focus display is performed in step S5 of FIG.

Although one zoom position has been described so far, a correction amount may be obtained by interpolation calculation from a correction value from a nearby value for a zoom position where an actual scanning operation such as shooting is not performed. A specific method may be a known method such as linear interpolation. For example, when the correction amount is obtained at the zoom positions z1 and z2 and the value is Corr (z1, ∞) · Corr (z2, ∞), the correction amount Corr (zp, ∞) at the zoom position zp during that time is
Corr (zp, ∞) = (Corr (z2, ∞) −Corr (z1, ∞)) · (z2−z1) / (z2−z1)
Is required. Therefore, detailed description is omitted.

  Although the first embodiment has been described by taking a compact digital camera as an example, the present invention can also be applied to a digital video camera and a digital SLR. In the first embodiment, a CMOS, a CCD, or the like can be applied as an image sensor.

[Example 2]
The second embodiment is different from the first embodiment in the scan range setting method in the step of FIG. The process will be described. A detailed description of the portion performing the same operation as in the first embodiment is omitted. When the process of step S401 in FIG. 4 is started, the CPU 15 detects the position of the zoom lens group 2 set as a result of the zooming operation in the same manner as in the first embodiment.

  Next, an adjustment value adj (z, ∞) corresponding to infinity corresponding to the position of the zoom lens group 2 (the focus lens corresponding to the position corresponding to infinity of the focus lens group 3 acquired in the manufacturing process) (Position of group 3) and position adjustment value adj (z, Near) corresponding to the closest distance (corresponding to a position corresponding to the closest distance set in each photographing mode of the focus lens group 3 acquired in the manufacturing process) The position of the focus lens group 3 to be read) is read from the EEPROM. This value is corrected in consideration of stop error, camera posture difference, vibration, drop, and other changes over time.

The position corresponding to infinity Pos (z, ∞) and the position Pos (Nea) corresponding to the closest distance for determining the scanning range are corrected according to the following equations.
Pos (z, ∞) = adj (z, ∞)-Err (z, ∞) + Angl (z)-Corr (z, ∞) (Formula 1-1)
Pos (z, Near) = adj (z, Near) + Err (z, Near) + Angl (z) (Formula 1-2)
Here, Err (z, ∞) and Err (z, Near) are correction amounts due to the displacement amount of the focus lens group 3 when the zoom stop position shifts, and Angl (z) is an adjustment in the manufacturing process. Corr (z, ∞) is the correction amount due to vibration, drop, and other changes over time, Err (z, ∞) ・ Angl (z ) ・ Err (z, Near) is a value determined by the time of manufacture based on the design value or measured value, and Corr (z, ∞) is a value determined based on the value acquired in actual use.

  Since the method of obtaining the correction amount Angl (z) due to the camera posture difference and the correction amount Corr (z, ∞) due to the change with time is the same as the embodiment, the correction amount due to the shift of the zoom stop position Err (z, ∞) and Err (z, Near) will be described.

  FIG. 7 is a view showing only the cam shown in FIG. 5 corresponding to the object at infinity, and shows the relationship between the design value and the actual value. The position of the focus lens group 3 at the time of focusing on infinity differs depending on each zoom position.

  In FIG. 7, the horizontal axis indicates the position of the zoom lens group 2, and the vertical axis indicates the position of the focus lens group 3. A solid curve written as ∞ cam design value indicates the position of the focus lens group 3 when the zoom lens group 2 is designed to focus at infinity. A dotted curve written as ∞ cam actual value indicates the position of the focus lens group 3 when the zoom lens group 2 is actually focused at infinity. In this way, the position of the focus lens group 3 when focusing at an actual infinity often differs from the design value. These are caused by manufacturing tolerances of the respective members constituting the lens barrel 31, and the larger the deviation from the design value of the actual cam value, the larger the correction amount caused by the shift of the zoom stop position must be taken.

  Therefore, an evaluation amount representing the degree of deviation from the position of the focus lens group 3 when focused on the design infinity and the position of the focus lens group 3 when focused on the actual infinity at the adjustment zoom position. Ec is obtained, and the correction amount Err (z, ∞) is determined according to this amount. In the adjustment zoom position shown in the figure, the focus lens group 3 is obtained when the focus is actually made to the position corresponding to infinity. In the figure, there are six zoom positions for acquiring the position of the focus lens group 3 for the sake of space, but in practice, the zoom positions are determined in consideration of the optical characteristics of the photographing optical system, the configuration of the lens barrel 31, and the like. .

  The position (adjustment value) of the focus lens group 3 when focused on the position corresponding to infinity acquired at the adjustment zoom positions Z0 to Zn is set to p0 to pn and the position corresponding to infinity at the designed adjustment zoom position, respectively. When the position (design value) of the focus lens group 3 in the in-focus state is p0d to pnd, respectively, it is first normalized with the adjustment value and the design value at the adjustment zoom position Z0. This is because the offset of the entire cam is not related to the magnitude of the shift of the in-focus position caused by the shift of the zoom stop position, so that the influence of the offset on the evaluation amount is removed.

The amount Δ is Δ = p0d-p0
And Therefore, the adjustment value pin obtained by normalizing the adjustment value pi at an arbitrary adjustment zoom position Zi is
pin = pi + Δ
Therefore, the sum of the squares of the differences between the normalized adjustment value and the design value at the adjustment zoom position is obtained. That is, the evaluation amount Ec is
n
Ec = Σ (pi-pid + Δ)
I = 0
I ask. This value becomes zero if the actual adjustment value and the design value are the same except for the offset (if the adjusted cam shape and the design cam shape are the same).

Therefore, the correction amount Err (z, ∞) from the correction amount Err0 (z, ∞) at the infinity position due to the zoom stop position shift when the difference between the actual adjustment value and the design value of the cam shape is not considered,
Err (z, ∞) = Err0 (z, ∞) · (N · Ec + 1) / (Ec + 1)
I ask. The correction amount Err0 (z, ∞) is obtained as follows.

  As described in the first embodiment, if it is attempted to acquire the adjustment value adj (z, ∞) at the position corresponding to infinity at the zoom lens position Zpo, the zoom lens group 2 is stopped when the actual adjustment value is acquired. The position may exist between Zpo− and Zpo +. Therefore, the difference in the position of the focus lens group 3 on the design value that focuses on the position corresponding to infinity when the stop position of the zoom lens group 2 is Zpo− and Zpo + is obtained at the position of the zoom lens group 2. The correction amount Err0 (z, ∞) at the infinity position caused by the shift of the zoom stop position is used. Similarly, the correction amount Err (z, Near) at the closest position caused by the shift of the zoom stop position is obtained.

  Using the correction amount obtained in this way, the position of the focus lens group 3 corresponding to the corrected infinity / close distance is obtained from (Equation 1-1) and (Equation 1-2). The scan start position is a position on the ultra-infinity side from Pos (z, ∞) by the scan interval, and the scan end position is a position closer to the scan interval than Pos (z, Near). The reason why a margin for the scan interval is provided is to ensure that the AF evaluation value peak exists for an object at infinity and close distance. By obtaining an AF evaluation value that is one scan more than the position of the focus lens group 3 when focusing at infinity / closest distance, an AF evaluation value lower than the in-focus position can be obtained on both sides of the position. it can. However, the obtained scan start position and scan end position are limited within a range in which the driving range and optical performance of the focus lens group 3 are guaranteed.

[Example 3]
The difference of the third embodiment from the first and second embodiments is that the setting method of the scan range setting method in FIG. 4 differs depending on the shooting mode. The process will be described. A detailed description of the portion performing the same operation as in the first embodiment is omitted. When the process of step S401 in FIG. 4 is started, the CPU 15 detects the position of the zoom lens group 2 set as a result of the zooming operation in the same manner as in the first embodiment.

  Next, an adjustment value adj (z, ∞) corresponding to infinity corresponding to the position of the zoom lens group 2 (the focus lens corresponding to the position corresponding to infinity of the focus lens group 3 acquired in the manufacturing process) (Position of group 3) and position adjustment value adj (z, Near) corresponding to the closest distance (corresponding to a position corresponding to the closest distance set in each photographing mode of the focus lens group 3 acquired in the manufacturing process) The position of the focus lens group 3 to be read) is read from the EEPROM. Subsequently, the photographing mode set by the photographer is read.

If the photographing mode is the portrait mode, the position corresponding to infinity Pos (z, ∞) for determining the scanning range and the position Pos (Nea) corresponding to the closest distance are determined as follows.
Pos (z, ∞) = adj (z, ∞)
Pos (z, Near) = adj (z, Near)
This is because in portrait mode, the entire body is shot from the half of the person according to the angle of view, so the shooting distance is limited to a few meters, so the position corresponding to infinity Pos (z, ∞) and the position corresponding to the closest distance This is because it is possible to focus on the subject even if Pos (Nea) has some errors. And it becomes possible to avoid extending AF time by expanding a scanning range.

If the shooting mode is the distant view mode, the position corresponding to infinity Pos (z, ∞) for determining the scan range and the position Pos (Nea) corresponding to the closest distance are determined as follows.
Pos (z, ∞) = adj (z, ∞)-Err (z, ∞) + Angl (z)-Corr (z, ∞)
Pos (z, Near) = adj (z, Near)
In this way, only the position corresponding to infinity Pos (z, ∞) is corrected in consideration of stop error, camera posture difference, vibration, drop, and other changes over time.

  This is because in the distant view mode, a subject at a long distance near infinity is photographed, so it is possible to focus on the subject even if the position Pos (Nea) corresponding to the close range has a slight error. Because. And it becomes possible to avoid extending AF time by expanding a scanning range.

Further, when the photographing mode is the macro mode, the position corresponding to infinity Pos (z, ∞) for determining the scanning range and the position Pos (Nea) corresponding to the closest distance are determined by the following equations.
Pos (z, ∞) = adj (z, ∞)
Pos (z, Near) = adj (z, Near) + Err (z, Near) + Angl (z)
In this way, only the position Pos (Nea) corresponding to the closest distance is corrected in consideration of the stop error and the camera posture difference. This is because in macro mode, a subject at a distance close to the subject is photographed, so it is possible to focus on the subject even if the position corresponding to infinity Pos (z, ∞) has some error. It is. And it becomes possible to avoid extending AF time by expanding a scanning range. The method of obtaining each correction amount is as described in the first embodiment.

  In this manner, the position of the focus lens group 3 corresponding to the corrected infinity / closest distance in each photographing mode is obtained. The scan start position is a position on the ultra-infinity side from Pos (z, ∞) by the scan interval, and the scan end position is a position closer to the scan interval than Pos (z, Near). The reason why a margin for the scan interval is provided is to ensure that the AF evaluation value peak exists for an object at infinity and close distance. By obtaining an AF evaluation value that is one scan more than the position of the focus lens group 3 when focusing at infinity / closest distance, an AF evaluation value lower than the in-focus position can be obtained on both sides of the position. it can. However, the obtained scan start position and scan end position are limited within a range in which the driving range and optical performance of the focus lens group 3 are guaranteed.

[Example 4]
The difference between the fourth embodiment and the first embodiment is that the adjustment value adj (z, ∞) is obtained multiple times in the process of obtaining the correction amount Corr (z, ∞) caused by vibration, dropping, and other changes with time. The peak position of the obtained AF evaluation value is used. As in the first embodiment, in step S407 in FIG. 4, a process for obtaining a correction amount Corr (z, ∞) due to vibration, drop, and other changes with time of the adjustment value adj (z, ∞) is performed.

FIG. 8 shows the operation procedure. First, in step S801, the position Pos [Peak] of the focus lens group 3 at which the AF evaluation value reaches a peak is set as in the first embodiment.
Pos [Peak] = Pos [1] + (d [0]-d [2]) * (Pos [1]-Pos [0]) / (d [0]-d [1]) / 2
(Formula 3)
I ask. Pos [0], Pos [1] (= adj (z, ∞)) is the position of the focus lens group 3 that acquired the AF evaluation value, and d [0], d [1], d [2] are Pos [0 ], AF evaluation values for Pos [1] and Pos [2].

In step S802, it is determined whether it is appropriate to obtain the correction amount. Since the contents are the same as those in the first embodiment, the description is omitted. If it is determined that it is appropriate to obtain the correction amount, the process proceeds to step S803. If it is determined that the correction amount is not appropriate, the process proceeds to step S408 in FIG. In step S803, the zoom position from which the peak position of the AF evaluation value is acquired is referred to. The peak position Pos [Peak] obtained in step S804 is the infinity equivalent position Pos (z, ∞) −α <Pos [Peak] <infinity equivalent position Pos (z, ∞) + α
It is determined whether or not the above is satisfied. For example, α may be set to a value that is one third to one half of the scan interval.

This is to determine whether or not Pos [Peak] has deviated greatly with respect to the position corresponding to infinity. If it deviates greatly, a change with time has occurred, and the correction amount Corr (z, ∞) needs to be changed. is there.
If Pos [Peak] is within the predetermined range and there is no need to change the correction amount, the process proceeds to step S408 in FIG. If it is necessary to change the correction amount, it is determined in step S805 whether Pos [Peak] is on the very infinite side or the near side from Pos (z, ∞). If it is on the near side, the process proceeds to step S806, and 1 is added to the counter det (z, pulus) that counts the number of times of continuous deviation to the near side, and the counter that counts the number of times of deviation that is continuously on the ultra-infinity side. Clear det (z, minus).

  If it is on the infinity side, the process proceeds to step S807, and 1 is added to the counter det (z, minus) that counts the number of times of continuous deviation to the ultra-infinity side, and the number of times of deviation continuously to the nearest side is counted. Clear counter det (z, puls). In step S808, the obtained peak position Pos [Peak] is recorded. In step S809, it is checked whether the counter det (z, minus) or det (z, puls) that counts the number of consecutive deviations is greater than or equal to a predetermined value. That is, it is determined whether or not the peak position Pos [Peak] is continuously shifted in the same direction a predetermined number of times.

If it is not continuously shifted in the same direction a predetermined number of times, the process proceeds to step S408 in FIG. If there is a continuous shift in the same direction, the correction amount Corr (z, ∞) due to vibration, drop, or other change over time is changed in step S810. The average of the positions of the focus lens group 3 at which the AF evaluation values for the past predetermined number of times recorded are the peak is obtained, and this average value Ave_Pos [Peak] is set to the scan start position at a position that is more than the infinite distance by the scan interval. Therefore, the correction amount Corr (z, ∞) due to vibration, drop, and other changes over time
Corr (z, ∞) = adj (z, ∞)-Err (z, ∞) + Angl (z)-Ave_Pos [Peak]
Ask and record.

  However, the position of the focus lens group 3 corresponding to the infinitely far side from the adjustment value adj (z, ∞) of the position corresponding to infinity corresponding to the position of the zoom lens group 2 obtained at the time of manufacture is equal to Do not deviate from the scan range. In other words, Corr (z, ∞) in the above equation does not take a negative value.

  Although the first to fourth embodiments have been described by taking a compact digital camera as an example, the present invention can also be applied to a digital video camera and a digital SLR. In the first to third embodiments, a CMOS, a CCD, or the like can be applied as an image sensor.

  The present invention can be used for an automatic focus adjustment apparatus having a focus position detection unit that detects a focus position from an image signal of a partial region of an image sensor.

1 imaging device, 2 zoom lens group, 3 focus lens group, 4 aperture,
5 solid-state imaging device (sensor), 6 imaging circuit, 7 A / D conversion circuit,
8 Memory (VRAM) such as buffer memory for temporarily storing image signals,
9 D / A conversion circuit, 10 Image display device such as liquid crystal display (LCD),
12 memory for storing image data,
11 A compression / decompression circuit comprising: a compression circuit that reads an image signal temporarily stored in the VRAM 8 and performs compression processing or encoding processing of the image data on the storage memory 12; and a decompression circuit that performs decoding processing or decompression processing;
13 AE processing circuit, 14 scan AF processing circuit,
15 CPU with built-in memory for calculation, 16 timing generator,
17 Sensor driver,
18 a first motor drive circuit for driving and controlling the aperture drive motor 21;
19 A second motor drive circuit for driving and controlling the focus drive motor 22;
21 aperture drive motor, 22 focus drive motor, 23 zoom drive motor,
20 Third motor drive circuit for controlling the drive of the zoom drive motor 23, 24 operation switches,
25 EEPROM, 26 battery, 28 strobe light emitting part,
27 A switching circuit for controlling flash emission,
29 LED and other display elements that display warnings, etc.
30 Speakers for voice guidance and warnings,
31 an imaging lens barrel, 32 an AF auxiliary light driving circuit for driving the AF auxiliary light 32,
33 AF assist light, 34 shake detection circuit, 35 shake detection sensor, 36 face detection circuit

Claims (11)

An imaging optical system capable of zooming, an imaging means for photoelectrically converting a subject image formed by the imaging optical system to obtain an electrical image signal, and focus adjustment for adjusting the focus of the subject image formed on the imaging means In the automatic focus adjustment apparatus having a focus position detection means for detecting a focus position from an image signal of a partial area of the imaging means generated by the imaging means while driving the focus adjustment means,
The range in which the focus adjustment unit is driven to obtain an image signal for detecting the in-focus position is determined by setting the target position of the variable power optical system and the predicted deviation of the actual stop position of the variable power optical system with respect to the set target position. An automatic focus adjustment device characterized by determining from The signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup means generated by the image pickup means while driving the focus adjustment means at a predetermined distance with respect to the setting position of the variable magnification optical system is maximum. Based on the difference between the position of the focus adjusting means on the design value and the position of the focus adjusting means actually measured, the set target position of the variable power optical system and the actual stop position of the variable power optical system with respect to the set target position 2. The automatic range according to claim 1, wherein a predicted value of the deviation is estimated, and a range for driving the focus adjusting means is determined from the estimated value to obtain an image signal for detecting a focus position. Focus adjustment device. Based on the difference between the attitude when starting the automatic focus adjustment device and the attitude when actually acquiring the signal value for detecting the in-focus position, the actual change with respect to the set target position and the set target position of the variable magnification optical system is determined. A prediction value of the stop position shift of the doubling optical system is estimated, and a range in which the focus adjustment unit is driven is determined from the estimated value to obtain an image signal for detecting a focus position. Item 2. The automatic focusing apparatus according to Item 1. While driving an imaging unit that photoelectrically converts a subject image formed by the photographing optical system to obtain an electrical image signal, a focus adjustment unit that adjusts the focus of the subject image formed on the imaging unit, and a focus adjustment unit while driving In an automatic focus adjustment apparatus having an in-focus position detecting means for detecting an in-focus position from an image signal of a partial region of the image pickup means generated by the image pickup means,
While driving the focus adjustment means, the signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup means generated by the image pickup means is maximized at the position of the actually measured focus adjustment means. An automatic focus adjustment apparatus, wherein a range for driving the focus adjustment means is determined to obtain an image signal for detecting a focus position. The position of the focus adjustment unit actually measured at which the signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup unit generated by the image pickup unit while driving the focus adjustment unit is maximized. Focus adjustment means for obtaining an image signal for detecting the focus position when the focus adjustment means is out of a range for driving the focus adjustment means for obtaining an image signal for detecting the focus position obtained in advance. The automatic focus adjustment apparatus according to claim 4, wherein a range in which the lens is driven is changed. The position of the focus adjustment unit actually measured at which the signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup unit generated by the image pickup unit while driving the focus adjustment unit is maximized. The focus adjusting means for obtaining the image signal for detecting the in-focus position when the focus adjusting means corresponding to the in-focus position of the subject at infinity which has been obtained in advance is on the ultra-infinite side from the position. The automatic focus adjustment apparatus according to claim 4, wherein a range in which the lens is driven is changed. While driving the focus adjustment means, the signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup means generated by the image pickup means is maximized at the position of the actually measured focus adjustment means. Based on the signal obtained from the image signal of the whole or a part of the image pickup means, it is determined whether to change the range for driving the focus adjustment means to obtain the image signal for detecting the in-focus position. The automatic focus adjustment apparatus according to claim 4. While driving the focus adjustment means, the signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup means generated by the image pickup means is maximized at the position of the actually measured focus adjustment means. 5. The autofocus according to claim 4, wherein whether or not to change a range for driving the focus adjusting means to obtain an image signal for detecting a focus position is determined based on temperature or humidity. Adjustment device. When driving the focus adjusting means to obtain the image signal for detecting the in-focus position, whether to change the range for driving the focus adjusting means to obtain the image signal for detecting the in-focus position. The automatic focus adjustment apparatus according to claim 4, wherein the determination is based on the color temperature of the light source, the contrast of the image signal, or the subject brightness. The position of the focus adjustment unit actually measured at which the signal value for detecting the in-focus position obtained from the image signal of the partial area of the image pickup unit generated by the image pickup unit while driving the focus adjustment unit is maximized. In order to obtain an image signal for detecting the in-focus position when the focus adjustment means corresponding to the in-focus position of the object at infinity, which has been obtained in advance a predetermined number of times, differs from the position by a predetermined amount or more 5. The automatic focus adjusting apparatus according to claim 4, wherein a range for driving the focus adjusting means is changed. The focus adjustment means is driven to obtain an image signal for detecting a focus position determined from a set target position of the variable magnification optical system and a predicted value of the actual stop position of the variable magnification optical system with respect to the set target position. 5. The automatic focus adjustment apparatus according to claim 1, wherein the range varies depending on the shooting mode.