JP2005189532A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of performing a focusing appropriately in accordance with the operating state of a shutter button. <P>SOLUTION: When a time interval between the half-press operation and full-press operation of the shutter button is short, the focusing is performed only by an outside light passive system. In addition, regardless of the position of a main subject, the focusing is performed by using the subject distance of a block located in the center of the ranging area AR2 of a ranging part. In the case of a setting in an FFP mode, however, priority should be given to focusing in the position specified as a focused position. Therefore, the outside light passive system and a hill-climbing detection system are both used even when the time interval between both the operations of the shutter button is short. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus having a focus adjustment function using an external light passive method having a plurality of distance measuring points and a focus adjustment function using a so-called hill-climbing detection method.

  In an imaging apparatus, apart from an imaging optical system and an imaging element for obtaining an image to be recorded, a plurality of optical systems (ranging optical systems) and imaging elements (corresponding to each ranging optical system) A distance measuring image pickup device), and each of the distance image pickup elements receives a light image formed through the distance measuring optical system to perform an image pickup operation and output the distance measuring image pickup device. A so-called external light passive focus adjustment method is known in which the subject distance is calculated based on the amount of deviation of the imaging position of each optical image obtained from the above, and the focus lens is driven to the focal position corresponding to the subject distance. (For example, see Patent Document 1 below).

  As another focus adjustment method of the image pickup apparatus, the focus lens position where the contrast of the image obtained by the image pickup operation is maximized while alternately driving the focus lens in the optical axis direction and the image pickup operation by the image pickup device. A so-called hill-climbing detection type focus adjustment method in which a focus lens is located at the position is also known.

  When comparing the focus adjustment method using the external light passive method and the focus adjustment method using the hill-climbing detection method, the focus adjustment method using the external light passive method performs the focus adjustment in a shorter time than the focus adjustment using the hill-climbing detection method. On the other hand, the external light passive method measures the distance with an optical system different from the imaging optical system, converts the distance value obtained by the distance measurement into the driving amount of the focus lens in the imaging optical system, and Since the focus lens is driven based on the driving amount, a calculation error and a mechanical error at the time of driving / stopping the focus lens occur at that time. Furthermore, at the wide-side focal length of the imaging optical system, there is a problem that only a part of the entire captured image can be measured (if the entire area can be measured, the distance measuring device can be increased in size and cost). In addition, depending on the subject distance, there arises a problem of parallax (parallax) between the imaging optical system and the distance measuring optical system. On the other hand, the focus adjustment method using the hill-climbing detection method is a target region where the entire area of the captured image can be adjusted and the focus adjustment accuracy is high, but the time required for the focus adjustment compared to the external light passive method. long.

Therefore, in order to perform focus adjustment using the advantages of both methods, a combination of both methods is used. First, the focus lens is driven roughly to the position by the external light passive method, and then the focus is adjusted roughly. It is conceivable to perform focus adjustment with high accuracy by the hill-climbing detection method using the image of the image sensor at the position corresponding to the main subject detected during the optical passive distance measurement.
JP-A-9-212315

  By the way, normally, an imaging apparatus is provided with a shutter button for inputting an instruction for instructing the imaging apparatus to obtain image data for recording, and the shutter button is depressed halfway, for example. The pressing operation is configured in two stages, that is, a half-pressing operation and a full-pressing operation that completely presses down. When the shutter button is pressed halfway, shooting preparation processing such as setting various control values such as exposure control values and adjusting the focus of the imaging optical system is executed, and when the full press operation is performed, Imaging of a subject image for recording in a predetermined recording means is executed with the control value set during the half-press operation.

  When the shutter button is configured to be pressed in two stages as described above, when the shutter button is pressed all at once, the subject at the timing when the photographer performs the full pressing operation. Often you want to get a statue.

  However, even in such a case, the following problems occur when focus adjustment is performed by combining the focus adjustment method of the external light passive method and the focus adjustment method of the hill-climbing detection method. That is, the focus adjustment is performed only by the hill-climbing detection method by detecting the target (main subject) to be focused by the focus adjustment of the external light passive method and performing the focus adjustment of the hill-climbing detection method using the image of the main subject. Although the time required for focus adjustment will be shorter than usual, the focus adjustment of this hill-climbing detection method requires a relatively long time, so the timing at which the photographer performs a full-press operation There is a possibility that a relatively large time lag occurs between the image sensor and the timing at which the image sensor actually captures the subject image for recording, and an image different from the subject image desired by the photographer may be obtained.

  On the other hand, there is a relatively large time difference between the half-press operation and full-press operation of the shutter button, and the focus adjustment by the external light passive method and the focus adjustment by the hill-climbing detection method can be completed by the full-press operation. Therefore, it is possible to perform the focus adjustment in which both the accuracy and the time of the focus adjustment are compatible by performing the focus adjustment in which both methods are combined.

  For these reasons, it is not always the best focus adjustment method to perform focus adjustment combining both types of focus adjustment methods, and it is a case where an imaging apparatus having both types of focus adjustment functions is proposed. However, it is thought that the use of these focus adjustment functions should be changed according to the operating state of the shutter button.

  The present invention has been made in view of such circumstances, and in an imaging device equipped with a function of performing focus adjustment by an external light passive method and a function of performing adjustment by a hill-climbing detection method, the operation state of a shutter button The purpose is to adjust the focus appropriately according to the situation.

  The invention described in claim 1 includes an imaging unit that captures an optical image of a subject by photoelectric conversion, and a focus adjustment unit that focuses the focal position of the imaging lens on the imaging surface of the imaging unit. An imaging optical system for forming a subject image on the imaging surface of the imaging means, an evaluation means for evaluating the clarity of an image obtained by the imaging operation of the imaging means, a pair of ranging optical systems, and each ranging An external light passive type distance measuring means comprising a plurality of distance measuring sensors provided with a plurality of distance measuring points corresponding to an optical system for use, and a subject distance detected by the distance measuring means The focus adjusting unit performs the focusing operation using the first control unit that causes the focus adjusting unit to perform the focusing operation, the subject distance detected by the distance measuring unit, and the evaluation performed by the evaluating unit. Second control means for controlling and recording imaging operation A first operating means for performing an input for instructing an imaging preparation operation for determining a control value; and a second operating means for performing an input for instructing the imaging means to start the recording imaging operation. The object distance obtained from a predetermined partial area of the distance measuring area of the distance measuring means when the second operation means is operated from the operation timing of the first operating means to a predetermined timing. When the first control unit is caused to execute control for causing the focus adjustment unit to perform the focusing operation using the second adjustment unit, the second operation unit is not operated by the predetermined timing. An imaging apparatus comprising: setting means for executing control by the control means.

  According to a second aspect of the present invention, in the imaging apparatus according to the first aspect, the predetermined partial area is a distance measuring point located in a central part of the distance measuring area of the distance measuring means. It is what.

  According to a third aspect of the present invention, in the imaging device according to the first aspect, the distance measuring sensor includes a plurality of pixels that photoelectrically convert a light image of a subject two-dimensionally arranged in two intersecting directions. The predetermined partial area is a center distance measuring point in the distance measuring area of the distance measuring means, and one of the two directions with respect to the center distance measuring point. It is an area composed of one or a plurality of distance measuring points arranged in a row.

  According to a fourth aspect of the present invention, in the imaging apparatus according to any one of the first to third aspects, the second control means uses the subject distance detected by the distance measuring means to the focus adjusting means. After the focusing operation is performed, the focus adjustment unit is caused to perform the focusing operation by using the evaluation by the evaluation unit.

  According to a fifth aspect of the present invention, in the imaging apparatus according to any one of the first to fourth aspects, a diaphragm for adjusting a light amount of a light image of a subject guided to the imaging means, and an aperture diameter of the diaphragm are controlled. And a subject brightness detecting means for detecting the brightness of the subject. When the control by the first control means is performed, the brightness of the subject detected by the subject brightness detecting means is a predetermined brightness. When larger, the diaphragm control means performs a process of reducing the aperture diameter of the diaphragm.

  According to a sixth aspect of the present invention, in the imaging device according to any one of the first to fifth aspects, the in-focus manual setting mode in which an input for designating a focal point can be performed from the imaging region of the imaging unit is set. Mode setting means and an operation means for performing input for designating a focal point. When the mode setting means is set to the in-focus manual setting mode by the mode setting means, the first and first Regardless of the operation time interval for the two operation means, at least the focusing operation using the evaluation by the evaluation means is performed by the focus adjustment means.

  According to the first aspect of the present invention, when the second operation means is operated from the operation timing of the first operation means to a predetermined timing, a predetermined one of the distance measurement areas of the distance measurement means is selected. Since the focus adjustment unit is made to perform the focusing operation using the subject distance obtained from the partial area, the focusing operation is quickly performed and the recording imaging operation is started by appropriately setting the predetermined timing. It becomes possible to do. As a result, an image close to the subject image desired by the user of the imaging apparatus can be obtained as a recorded image.

  Further, when the second operation means is not operated by the predetermined timing, the focus adjustment means is caused to perform the focusing operation using the subject distance detected by the distance measurement means and the evaluation by the evaluation means. As a result, it is possible to perform focus adjustment that balances the accuracy and time of focus adjustment.

  According to the second aspect of the present invention, since the predetermined partial area is limited to the distance measuring point located in the center part of the distance measuring area of the distance measuring means, the focusing operation is quickly performed and recording is performed. By performing the focusing operation based on the central ranging point where the main subject having the highest importance among the plurality of subjects is likely to be arranged, Ranging accuracy can be ensured while giving top priority to the speed of focusing operation (fast time).

  According to a third aspect of the present invention, the predetermined partial area is selected from any one of the two distance directions with respect to the central distance measuring point in the distance measuring area of the distance measuring means and the second distance from the central distance measuring point. Since the area is composed of one or a plurality of distance measuring points arranged in the direction of 1, the distance measurement accuracy can be ensured more than the invention according to claim 2.

  According to a fourth aspect of the present invention, the second control means causes the focus adjusting means to perform a focusing operation using the subject distance detected by the distance measuring means, and then the evaluation by the evaluation means. Since the focus adjustment means is caused to perform a focusing operation using the lens, when the control is set by the second control means, the focus adjustment in which the precision and time of the focus adjustment are compatible can be performed. .

  According to the fifth aspect of the present invention, when the focus adjustment unit performs the focusing operation using the subject distance detected by the distance measuring unit, and the detected luminance of the subject is larger than the predetermined luminance, Since the process of reducing the aperture diameter of the diaphragm is performed by the diaphragm control means, it is possible to compensate for the lack of focusing accuracy by not performing the focusing operation using the evaluation by the evaluation means.

  According to the sixth aspect of the present invention, when the in-focus manual setting mode is set, at least focusing using the evaluation by the evaluation unit is performed regardless of the operation time interval for the first and second operation units. Since the operation is performed by the focus adjusting means, it is possible to prioritize focusing at the designated in-focus point over the time of the in-focus operation, and the user who sets to the in-focus manual setting mode can perform the operation. Can reflect the intention.

  Hereinafter, an embodiment of an imaging device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing the configuration of the imaging apparatus, and FIG. 2 is a rear view of the imaging apparatus.

  As shown in FIGS. 1 and 2, the imaging apparatus 1 includes an imaging optical system 2 disposed at a proper position on the front surface, a mode setting dial 3 disposed at a proper position on the upper surface, and a shutter disposed at an upper corner. A button 4, an LCD (Liquid Crystal Display) 5 disposed on the left side of the back surface, a cross operation unit 6 disposed on the side of the LCD 5, and a push button 7 disposed on the inner side of the cross operation unit 6. A set button group 8 disposed below the LCD 5, an electronic view finder (hereinafter abbreviated as EVF) 9 disposed above the LCD 5, and an imaging optical system 2. A photometric unit 10, a distance measuring unit 11 disposed adjacent to the photometric unit 10, a flash 12 disposed above the EVF 9, and an AF auxiliary light emitting unit 13 disposed at an appropriate position on the front surface. Yes.

  Referring to FIG. 8, the imaging optical system 2 includes a zoom lens 19 for changing a photographing magnification (focal length) and a focus lens 20 for adjusting a focal position (corresponding to a focus adjusting unit in claims). ) And a diaphragm 21 for adjusting the amount of light to the image sensor 23 are arranged in the direction of the optical axis L1 (see FIG. 6) in the lens barrel 2a provided so as to protrude from the apparatus main body 1A. The optical image of the subject is taken in and formed on the image sensor 23. The imaging magnification (focal length) is changed and the focal position is adjusted by driving each lens of the imaging optical system 2 in the direction of the optical axis L1 by a drive system such as a motor (not shown).

  The mode setting dial 3 is a substantially disk-shaped member that can be rotated in a plane substantially parallel to the upper surface of the imaging device 1, and includes a shooting mode for shooting a still image or a moving image, a playback mode for playing back a recorded image, Alternatively, the mode and function mounted in the imaging apparatus 1 such as switching of power ON / OFF can be selected alternatively. Although not shown, on the upper surface of the mode setting dial 3, characters indicating the respective functions are written at predetermined intervals along the outer peripheral edge of the mode setting dial 3, and are opposed to indexes provided at appropriate positions on the apparatus main body 1 a side. The function corresponding to the character set at the position is executed.

  The shutter button 4 is a button that is pressed in two stages, that is, a half-pressing operation in which it is pressed halfway and a full-pressing operation in which it is fully pressed. The shutter button 4 corresponds to the first and second operation means in the claims, the half-press operation corresponds to the operation of the first operation means, and the full-press operation corresponds to the operation of the second operation means. In the shooting mode, when the shutter button 4 is not operated, an optical image of the subject is captured at a constant cycle (for example, every 1/30 (second)), and images generated by the imaging are sequentially displayed on the LCD 5 and the EVF 9. The display is switched. The series of images displayed on the LCD 5 or the like at this time is hereinafter referred to as a live view image in the sense that the state of the subject is displayed in substantially real time. By displaying the live view image, the photographer can visually recognize the state of the subject on the LCD 4.

  When the shutter button 4 is half-pressed, in addition to the display of the live view image, a shooting preparation process, mainly detecting the subject brightness and setting an exposure control value, and adjusting the focus of the imaging optical system 2 are performed. Processing to be performed is performed. Further, when the shutter button 4 is fully pressed, an object image to be recorded in an image storage unit 35 to be described later is captured with the exposure control value set when the shutter button 4 is pressed halfway. The half-pressing operation of the shutter button 4 is detected by turning on a switch S1 (not shown), and the full pressing operation of the shutter button 4 is detected by turning on a switch S2 (not shown).

  The LCD 5 includes a color liquid crystal panel, and displays a live view image, a reproduction display of a recorded image, and the like, and displays a setting screen for functions and modes installed in the imaging apparatus 1. FIG. 3 shows how a plurality of subjects are displayed on the display screen of the LCD 5. Instead of the LCD 5, an organic EL or a plasma display device may be used.

  The cross operation unit 6 includes an annular member having pressing parts 6a to 6d arranged in a cross shape, and the pressing part 6a is provided by a contact (switch) (not shown) provided corresponding to each pressing part 6a to 6d. ˜6d pressing operation is detected, the photographing magnification is changed (the zoom lens 19 is moved in the wide direction or the tele direction), the frame advance of the recorded image to be reproduced on the LCD 5, and the photographing condition This is for inputting an instruction for setting (aperture value, shutter speed, presence / absence of flash emission, etc.).

In addition, the present embodiment is provided with a flex focus point mode (hereinafter referred to as FFP mode) that can focus on an arbitrary subject in the shooting region. As shown in FIG. When set, the cursor CSR indicating the focus position (designated focus position) is superimposed on the subject image and displayed on the display screen of the LCD 5 or EVF 9. FIG. 3A shows a state in which the cursor CSR is displayed at the approximate center of the display screen of the LCD 5. Then, as shown in FIG. 3B, the cross operation unit 6 has a function of changing the position of the cursor CSR. FIG. 3B shows that the cursor CSR is moved in the direction of arrow P by operating 6a and 6d of the cross operation unit 6. The FFP mode corresponds to the in-focus manual setting mode in the claims.

  Returning to FIG. 1 and FIG. 2, the push button 7 is used to input for instructing the setting of the FFP mode and the determination of the designated position of the focus. Note that after the FFP mode is set by pressing the push button 7, an instruction to confirm the designated position of the focus is input by performing the pressing operation again. In addition, the cross operation part 6 and the push button 7 are equivalent to the operation means in a claim.

  Although not described in detail, the setting button group 8 is a button for performing operations on various functions installed in the imaging apparatus 1.

  The EVF 9 includes an unillustrated color liquid crystal panel and an eyepiece, and uses the luminous flux that passes through the photographing lens and is separated and guided by the unillustrated separation means and the light guide means to display an image of the subject on the color liquid crystal panel. The photographer can view a subject image similar to the subject image displayed on the display screen of the LCD 5 through the eyepiece lens by looking into the eyepiece window 9a.

  Although not shown, the photometric unit 10 includes a photometric optical system and a photometric sensor that captures a light image formed by the optical system, and performs photometry using these mechanisms. The subject brightness is calculated from the output of the photometry unit 10, and the detected subject brightness is used to determine the exposure control value (the exposure time of the image sensor 23 corresponding to the aperture value and the shutter speed).

  The distance measuring unit 11 is for detecting the subject distance in order to drive the focus lens 20 to a position corresponding to the distance (subject distance) from the imaging device 1 to the subject. 4A is a cross-sectional view showing the internal configuration of the distance measuring unit 11 in the present embodiment, and FIG. 4B is a distance measuring sensor in the distance measuring unit 11 when viewed from the arrow Q in FIG. 4A. FIG. 6 is a diagram illustrating a configuration of a unit 16.

  As shown in FIG. 4A, the distance measuring unit 11 has optical axes La and Lb different from the optical axis L1 (see FIG. 6) of the imaging optical system 2, and is a plane orthogonal to the optical axes La and Lb. A pair of distance measuring optical systems 14 and 15 arranged in parallel on the upper side, and a distance measuring sensor unit 16 arranged on a substantially imaging plane of the distance measuring optical systems 14 and 15 are configured. A subject image is picked up using the distance measuring optical systems 14 and 15 and the distance measuring sensor section 16. The output of the ranging sensor unit 16 is used for focus adjustment by an external light passive method (details will be described later).

  As shown in FIG. 4B, the ranging sensor unit 16 includes a plurality of line sensors L1 to L14 made of a solid-state imaging device such as a CCD, and a drive signal for data transfer to the line sensors L1 to L14. And a control circuit (not shown) for generating

  When the longitudinal direction of the line sensors L1 to L14 is the X-axis direction and the direction perpendicular to the X-axis direction is the Y-axis direction, the line sensors L1 to L7 are composed of line sensors L1 to L7 arranged substantially parallel to the Y-axis direction at predetermined intervals. A line sensor group 17 and a line sensor group 18 including line sensors L8 to L14 disposed substantially parallel to the Y axis direction at the predetermined interval are arranged in parallel at a predetermined interval in the X axis direction. .

  A subject optical image is formed on the imaging surface of the line sensor group 17 by the ranging optical system 14, while a subject optical image is formed on the imaging surface of the line sensor group 18 by the ranging optical system 15. Then, based on the pixel signals output from the line sensor groups 17 and 18, the distance to the subject (subject distance) is detected by the principle of triangulation, which will be described later.

  As shown in FIGS. 4 and 5, the distance measurement area AR <b> 2 is vertically and horizontally with respect to the imaging range AR <b> 1 when the zoom lens 19 is positioned at the wide end position where the subject in the widest range is imaged on the imaging device 23. The horizontal length is set to, for example, 50%, that is, an area ratio of 25% (illustrated by a dotted line).

  This is because, when the zoom lens 19 is located at the wide end position, if distance measurement is performed also on a subject located in the periphery of the imaging range AR1, the number of out-of-focus images increases on the contrary. If it is confirmed and an attempt is made to provide a distance measuring unit having a distance measuring area AR2 that is substantially equivalent to the imaging range AR1 when the zoom lens 19 is positioned at the wide end position, the distance measuring sensor unit 16 in the distance measuring unit. As the occupation area (light receiving area) increases, the size of the image pickup apparatus 1 is increased, and the amount of information associated with the increase in the number of pixels causes a burden on the main control unit 46 (described later) (information processing amount). This is because of the increase.

  FIG. 6 is a diagram showing the relationship between the shooting areas AR1 and AR3 when the zoom lens 19 is located at the wide end position and the tele end position, and the distance measuring area AR2 of the distance measuring unit 11.

  As shown in FIG. 6, for example, at a position away from the imaging device 1 by a distance L, when the zoom lens 19 is positioned at the wide (wide angle) end position, the range indicated by the arrow A is the imaging range AR1 of the imaging device 23. When the zoom lens 19 is located at the tele (telephoto) end position, the range indicated by the arrow B is the imaging range AR3 of the image sensor 23, which is smaller than the imaging range AR1 at the wide end position (AR3 <AR1). On the other hand, the distance measurement area AR2 of the distance measurement unit 11 is set to an area ratio of about 25% with respect to the image pickup range AR1 of the image pickup device 23 when the zoom lens 19 is located at the wide end position as described above. It is set larger than the imaging range AR3 of the imaging device 23 at the tele end position.

  By the way, when the subject distance is relatively small (when the subject is relatively close to the imaging device 1), the optical axis L1 of the imaging optical system 2 and the optical axes La and Lb of the distance measuring optical systems 14 and 15 are the same. The difference between the optical image guided to the image sensor 23 via the imaging optical system 2 and the optical image guided to the distance sensor unit 16 via the distance measuring optical systems 14 and 15 of the distance measuring unit 11 ( (Parallax, parallax) occurs. In particular, the parallax is small and hardly causes a problem in a region farther than 3 to 5 m from the imaging device 1, but the parallax becomes relatively large in a region closer than that.

  Therefore, in the imaging apparatus 1, in order to reduce this parallax, the optical axes La and Lb of the distance measuring unit 11 intersect with the optical axis L1 of the imaging optical system 2 at, for example, 3 to 5 m ahead (intersection P). In other words, it is designed to be inclined slightly downward with respect to the optical axis L1 of the imaging optical system 2. As described above, the position of the intersection P is set, for example, 3 to 5 m away from the imaging device 1. The most important subject (main subject) is usually 3 to 5 m away from the imaging device 1 and is photographed. In many cases, the optical axis La, Lb of the distance measuring unit 11 is excessively inclined (the position of the intersection P is set closer to the imaging device 1), and the distance measurement unit 11 performs measurement. This is because there is a possibility that the focus adjustment cannot be reliably performed on the main subject because the distance area AR2 is shifted upward or downward from the center of the imaging range.

  As can be seen from FIG. 6, by driving the zoom lens 19 from the wide-angle side to the telephoto side, the imaging range of the imaging device 23 is narrowed, while the distance measuring area AR2 of the distance measuring unit 11 is constant. The distance measuring area AR2 of the distance unit 11 is relatively large with respect to the imaging range of the imaging device 23, for example, from the state shown in FIG. 5 to the state shown in FIG. The distance measuring unit 11 corresponds to the distance measuring means in the claims.

  Returning to FIG. 1, the flash 12 reflects an arc tube composed of a xenon tube or the like that is converted into light energy by discharging electric energy and outputs flash light (flash light) emitted from the arc tube 1 to the front of the imaging device 1. A reflector, a Fresnel lens that condenses or diffuses flash light within a predetermined range, etc., and when an exposure amount to the image sensor 23 is insufficient, discharge is caused in a discharge tube (not shown). This is a pop-up flash that illuminates with illumination light. The operation of the flash 12 is controlled by a dimming circuit 37 (see FIG. 8) that outputs electric energy to the discharge tube.

  The AF auxiliary light emitting unit 13 includes a light emitting element such as an LED, and outputs auxiliary light when distance measurement is performed even when the brightness and contrast of the subject are small.

  Next, a block configuration of the imaging apparatus 1 will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the member etc. which are the same as FIGS.

  The photographic optical system 2 corresponds to the photographic optical system 2 shown in FIG. 1 and includes a zoom lens 19, a focus lens 20, and a diaphragm 21. The zoom lens 19 and the focus lens 20 are driven by the motors M1 and M2 in the direction of the optical axis L1 using a helicoid structure in the lens barrel 2a, and the diaphragm 21 is driven by the motor M3.

  In the photographic optical system 2, with respect to driving of the photographic lens, the photographic lens 2 shoots while being in sliding contact with the encode plate in which a plurality of code patterns are formed at a predetermined pitch in the optical axis L1 direction within the moving range of the photographic lens. A lens position detection unit 22 including an encoder brush that moves integrally with the lens is disposed. The lens position detection unit 22 detects the position of the photographing lens by reading the code pattern on the encoding plate with an encoder brush. The detected position of the photographing lens is used for calculating the focal length.

  The image sensor 23 has a plurality of photoelectric conversion elements, such as photodiodes, that are two-dimensionally arranged in a matrix. The light receiving surfaces of the photoelectric conversion elements have different spectral characteristics, for example, R (red) and G (green). ), B (blue) color filters with a Bayer array CCD (Charge Coupled Device) color area sensor having a 1: 2: 1 ratio. The image sensor 23 converts the light image of the subject formed by the photographing lens into analog electrical signals (image signals) of R (red), G (green), and B (blue) color components. Output as B color image signals. Note that the image sensor 23 may be configured by a solid-state image sensor such as a complementary metal-oxide semiconductor (CMOS).

  The image pickup device 23 performs image pickup operations such as start and end of the exposure operation of the image pickup device 23 and reading of output signals of each pixel (horizontal synchronization, vertical synchronization, transfer) in the image pickup device 23 by a timing control circuit 26 described later. Be controlled. The imaging element 23 corresponds to the imaging means in the claims.

  The signal processing unit 24 performs predetermined analog signal processing on the analog image signal output from the image sensor 23. The signal processing unit 24 includes a CDS (correlated double sampling) circuit and an AGC (auto gain control) circuit, reduces noise of the image signal by the CDS circuit, and adjusts the level of the image signal by the AGC circuit.

  The A / D conversion unit 25 converts the analog R, G, B image signals output from the signal processing unit 24 into a plurality of bits (for example, 10 bits) based on a clock CLK2 output from a timing control circuit 26 described later. Bits) are converted into digital image signals.

  The timing control circuit 26 generates clocks CLK1 and CLK2 based on a reference clock CLK0 output from a main control unit 46, which will be described later. The clock CLK1 is used as the image sensor 23, and the clock CLK2 is used as the A / D conversion unit 25. By outputting each of them, the operations of the image sensor 23 and the A / D converter 25 are controlled.

  The image processing unit 27 converts a black level to a reference black level for each of the R, G, and B digital signals A / D converted by the A / D conversion unit 25 and a light source corresponding to the light source. A white balance circuit (WB circuit) 29 that performs digital signal level conversion of each color component of R (red), G (green), and B (blue) based on a white standard, and R (red) and G (green) ) And B (blue) are provided with a γ correction circuit 30 for correcting the γ characteristics of the digital signals of the respective colors.

  The image memory 31 temporarily stores the image data output from the image processing unit 27 in the photographing mode, and is also used as a work area for performing processing to be described later by the main control unit 46 on the image data. It is. Further, in the reproduction mode, the memory temporarily stores image data read from an image storage unit 35 described later.

  The VRAM 32 has a pixel signal recording capacity corresponding to the number of pixels of the LCD 5, and is a buffer memory between the main control unit 46 and the LCD 5. The VRAM 33 has a pixel signal recording capacity corresponding to the number of pixels of the EVF 9. And a buffer memory between the main control unit 46 and the EVF 9. LCD5 and EVF9 correspond to LCD5 and EVF9 shown in FIG. 2, respectively.

  The drive unit 34 includes motors M1 and M2 that drive the zoom lens 19 and the focus lens 20 in the direction of the optical axis L1, respectively, a motor M3 that drives the diaphragm 21, and the like.

  The image storage unit 35 includes a memory card, a hard disk, and the like, and stores an image generated by the main control unit 46.

  The input operation unit 36 includes the mode setting dial 3, the shutter button 4, the cross operation unit 6 and the push button 7 described above, and inputs operation information to the main control unit 46.

  The light emission control unit 37 controls light emission of the flash 12 based on the light emission control signal output from the main control unit 46, and includes a light control circuit 38 and a light control sensor 39. The light emission control signal includes a light emission preparation instruction, a light emission timing, and a light emission amount.

  The dimming circuit 38 charges a main capacitor (not shown) to emit light when a light emission preparation instruction signal is sent from the main control unit 46, and further synchronizes with the timing signal when a light emission timing signal is sent. Thus, the accumulated charge in the main capacitor is discharged, and the flash 12 is caused to emit light. The light control sensor 39 receives reflected light from the subject simultaneously with the start of exposure during flash photography. When the amount of reflected light received by the light control sensor 39 reaches a predetermined light emission amount, the main control unit 46 sends a light emission stop signal to the light control circuit 38. The light control circuit 38 stops the discharge of the main capacitor in response to the light emission stop signal, whereby the flash 12 emits light with a required light emission amount.

  The distance measuring unit 11 corresponds to the distance measuring unit 11 shown in FIG. 1, and includes the distance measuring optical systems 14 and 15, the distance measuring sensor unit 16, and the sub-control unit 40. The sub-control unit 40 controls the imaging operation by the distance sensor unit 16 and executes subject distance calculation processing using image data obtained by the imaging operation of the distance sensor unit 16. As shown in FIG. 3, the extraction unit 41, the correlation calculation unit 42, the corresponding position detection unit 43, the distance detection unit 44, and the reliability determination unit 45 are functionally configured.

  Here, the subject distance calculation process performed by the distance measuring unit 11 will be described. 9 to 11 are diagrams for explaining the principle of distance calculation by the external light passive method (triangular distance measurement method).

  As shown in FIG. 10, in the distance calculation by the external light passive method, each pixel of each line sensor L1 to L14 is divided into X (pieces) blocks for the left and right line sensor groups 17 and 18, respectively. With respect to a pair of blocks corresponding to each other between the line sensor group 17 and the right line sensor group 18, a pixel shift amount (number of pixels) with matching pixel data is derived, and the subject distance is determined for each block based on the shift amount. Is to be calculated. Specifically, the following processing is performed.

  The extraction unit 41 performs a process of extracting each pixel signal from a predetermined number of pixels including some or all of the pixels corresponding to the left line sensor group 17 and the right line sensor group 18.

  FIG. 11 illustrates the state of each pixel signal extracted from a predetermined number of pixels. The circles in FIG. 11 indicate the level of the pixel signal of each pixel constituting the left and right line sensor groups 17 and 18. It is shown as an example. FIG. 11 shows that extraction processing is performed a predetermined number of times, in this embodiment, 10 times.

  On the left line sensor group 17 side, a predetermined number of pixel data are extracted twice from the pixels located at a predetermined position inside, and the predetermined number of pixel data shifted outward by one pixel in the next two times. This operation is sequentially performed twice every two times, that is, a total of ten times while shifting one pixel every odd number of times. Similarly, on the right line sensor group 18 side, a predetermined number of pieces of pixel data are extracted once from pixels located at a predetermined position inside, and then a predetermined number of pieces of pixel data shifted outward by one pixel are converted into 2 pieces. These operations are sequentially performed every two times, that is, a total of ten times while shifting the pixel by one every even number of times. Hereinafter, a predetermined number of pixel data is referred to as partial image data.

  As described above, the extraction unit 41 extracts partial image data while sequentially switching from the left and right line sensor groups 17 and 18 from the first time to the tenth time shown in FIG. The correlation calculation unit 42 calculates the difference between the corresponding pixel data of the left and right line sensor groups 17 and 18 from the pixel data on the head side (for example, from the left side in FIG. 11) of the partial image data delivered each time. Find and calculate the sum.

  Specifically, among the partial image data extracted by the extraction unit 41 at a certain point in time (any of the first to tenth times), L (i) is the 1st to mth from the left line sensor group 17 side. When each pixel data is (i = 1 to m) and R (j) is each pixel data from 1 to n-th (j = 1 to n) on the right line sensor group 18 side (n = m) Alternatively, the correlation calculation unit 42 calculates the correlation coefficient expressed by the following equation 1 when the number of pixel data of the partial image data is expressed as k.

  The correlation coefficient calculated in this way is temporarily stored in an internal storage unit (not shown) in the sub-control unit 40. Then, correlation coefficient sequences (total 10 correlation coefficient sequences) for each extracted pattern are created. The corresponding position detection unit 43 specifies the number of extractions having the highest degree of correspondence, that is, the smallest correlation coefficient from the correlation coefficient string. In FIG. 11, the fifth extraction is the specific result.

  The distance detection unit 44 converts this identification result into a subject distance from the relationship between the correspondence position (extraction position) and the subject distance that are associated with each other in advance and are tabulated, for example. The lens position stored in advance in association with the calculated subject distance is read out from a table or the like. The reliability determination unit 45 determines that the distance cannot be detected when the contrast of the subject is low or the corresponding position cannot be detected. The above processing is performed for each block, and the subject distance for each block is calculated. Therefore, as shown in FIG. 10, if the line sensor groups 17 and 18 of the distance measuring unit 11 each have Y line sensors and each line sensor is divided into X blocks, the distance measuring unit 11 has X × Y (pieces) distance measuring points.

  Returning to FIG. 8, the main control unit 46 includes a microcomputer in which a storage unit 47 including, for example, a ROM that stores a control program, a flash memory that temporarily stores data, and the like is incorporated, and the imaging apparatus 1 illustrated in FIG. 8. The drive of each member is controlled in association with each other. In the present embodiment, the main control unit 46 functionally includes a mode setting unit 48, an AF control unit 49, and a display control unit 49.

  The mode setting unit 48 receives an operation signal from the mode setting dial 3 and sets a shooting mode for shooting a subject and a playback mode for playing back and displaying a shot image on the LCD 5 or the like. In addition to these functions, the mode setting unit 48 of the present embodiment can receive an operation signal from the push button 7 and focus on an arbitrary subject (designate a point to be focused). Set to FFP mode.

  The AF control unit 49 controls the operation of the motor M2 to position the focus lens 20 at the focal position. The imaging apparatus 1 according to the present embodiment is obtained by the function of performing focus adjustment by the external light passive method using the distance measuring unit 11 and the imaging operation of the imaging element 23 until the imaging operation for obtaining the recording image is performed. And a function of performing focus adjustment by a so-called hill-climbing detection method, which will be described later, using the contrast of the image (one parameter indicating the clarity of the image).

  When performing focus adjustment by the external light passive method, the AF control unit 49 instructs the distance measurement unit 11 (sub control unit 40) to perform a distance measurement operation, and the distance measurement value of each block calculated by the sub control unit 40 Based on the distance measurement value obtained by the external light passive method by the distance measurement unit 11, for example, the technique disclosed in Japanese Patent Laid-Open No. 14-298138 proposed by the present applicant is adopted and considered to be the most important. The main subject (mainly a person) to be detected is detected. That is, a three-dimensional coordinate system is set in which the horizontal direction of the shooting area is the X axis, the vertical direction is the Y axis, and the subject distance is an axis perpendicular to the XY plane (Z axis), and the subject distance corresponding to each block is set. Is plotted in this coordinate system to generate a three-dimensional distance image. Then, a person is detected from the distance image based on the ratio of the actual human face width and body width.

  When there is one person in the shooting area, the AF control unit 49 recognizes the person as a main subject, and at a position relatively close to the imaging device (a position where the subject distance is relatively small) in addition to the main subject. If a subject other than a person (for example, a car or a building) exists, the subject is determined as a sub-subject. Further, when there are two or more persons separated from each other in the shooting area, the AF control unit 49 has a small subject distance because the main subject is often closer to the imaging device 1 than the sub-subject. Since the subject (subject located closer to the imaging device) is set as the main subject, and then the main subject is considered to be placed closer to the center of the shooting area than the sub-subject, A person located closer to the center in the shooting area is set as the main subject.

  In addition, the imaging apparatus 1 according to the present embodiment has an FFP mode in which a focus position can be specified. When the focus position is specified in the FFP mode, the main subject determination method as described above. Regardless of the subject, the subject existing at the designated position is set as the main subject, and the other person is set as the sub-subject.

  On the other hand, when performing focus adjustment by the hill-climbing detection method, the AF control unit 49 performs the following processing. FIG. 12 is an explanatory diagram of focus adjustment by the hill-climbing detection method, and shows the relationship between the position of the focus lens 20 in the direction of the optical axis L1 and the contrast of the image obtained by the imaging operation of the imaging device 23.

As shown in FIG. 12, the contrast waveform with respect to the position of the focus lens 20 generally has the highest contrast when the focus lens 20 is positioned at a certain lens position, that is, the captured image is sharpest, and the focus is determined from the lens position. As the lens 20 moves toward the image side and subject side in the direction of the optical axis L1, a mountain-shaped waveform is obtained in which the contrast decreases. FIG. 12 shows that the contrast is maximized when the focus lens 20 is located at the lens position _Xmax when a certain subject is photographed by the imaging apparatus 1.

  The AF control unit 49 divides the entire area or a part of the image after A / D conversion into minute areas, detects the brightness for each area, and determines the difference in brightness between adjacent areas, that is, the contrast. To detect. This process is performed for each captured image while moving the focus lens 20 in the direction of the optical axis L1 to find a position where the contrast is maximum, and the focus lens 20 is positioned at that position.

That is, in FIG. 12, assuming that the focus lens 20 is located at a position X _{1 in the} optical axis direction (hereinafter referred to as a reference position X ₁ ) immediately after the power of the imaging apparatus 1 is turned on, the shutter button 4 is When half-pressed, the AF control unit 49 causes the image sensor 23 to capture a subject image with the focus lens 20 positioned at the position X ₁ and derives the contrast C (X ₁ ) from this image data. Next, the AF control unit 49 moves the focus lens 20 to, for example, the optical axis L1 direction image side by a preset movement pitch Δx, and performs imaging in a state where the focus lens 20 is located at the position X ₂ that is the movement destination. The image of the subject is picked up by the element 23, and the contrast C (X ₂ ) is derived from this image data. At this time, as can be seen from FIG. 12, since C (X ₁ )> C (X ₂ ), the AF control unit 49 does not increase the contrast even if the focus lens 20 is moved from the position X ₁ to the image side. And move from this position X ₂ to the subject side by the movement amount 2Δx (from the reference position X ₁ to the subject side by the movement pitch Δx).

Then, the AF control unit 49 causes the image sensor 23 to capture a subject image in a state where the focus lens 20 is located at the position X ₃ that is the movement destination, and derives the contrast C (X ₃ ) from this image data. At this time, since the contrasts C (X ₁ ) and C (X ₃ ) at the positions X ₁ and X ₃ are C (X ₁ ) <C (X ₃ ) as shown in FIG. control unit 49 determines from the position X ₁ by moving the focus lens 20 on the object side and the contrast is increased, moving further by movement pitch Δx from the position X ₃ of the focusing lens 20 on the object side.

Then, the AF control unit 49 causes the image sensor 23 to capture a subject image in a state where the focus lens 20 is located at the position X ₄ that is the movement destination, and derives the contrast C (X ₄ ) from this image data. At this time, since the magnitudes of C (X ₃ ) and C (X ₄ ) at the positions X ₃ and X ₄ are C (X ₃ ) <C (X ₄ ) as can be seen from FIG. 12, the AF control unit 49 moves the focus lens 20 from the position X ₄ to the subject side by the movement pitch Δx.

Thereafter, similarly, the AF control unit 49 repeatedly performs the derivation of the contrast, and the contrast C (X _n ) at the _nth derived position X _{n and} the contrast at the (n + 1) th derived position X _{n + 1} . When C (X _{n + 1} ) <C (X _n ) is compared with C (X _{n + 1} ), the position X _n is determined as the in-focus position, and the focus lens 20 is moved to the position X _n . Fix it. Thereby, the focus adjustment process by the hill-climbing detection method is completed. When C (X _{n + 1} ) = C (X _n ), it is determined that there is a maximum contrast value between the position X _n and the position X _{n + 1.} For example, the position X _n The focus lens 20 is positioned at an intermediate position between the position X _{n + 1} and the position X _{n + 1} .

  As described above, in the imaging apparatus 1 of the present embodiment having two types of focus adjustment functions, the focus adjustment function is performed by combining these focus adjustment functions according to the operation state of the shutter button, or one of the focus adjustment functions. It is characterized by the fact that the focus is adjusted independently.

  That is, the focus adjustment method using the external light passive method can perform the focus adjustment in a short time compared to the focus adjustment using the hill-climbing detection method, but as described above, there is a structural problem (for example, the distance measurement unit 11). Depending on the focal length, the distance measuring unit 11 may not be able to measure the entire area of the image obtained by the imaging optical system 2 and the imaging element 23, depending on the focal length. On the other hand, the focus adjustment method using the hill-climbing detection method has high focus adjustment accuracy and can focus on any subject in the imaging range, but it is more focused than the external light passive method. It takes a long time.

  On the other hand, when the time interval between the half-pressing operation and the full-pressing operation of the shutter button 4 is short (when the shutter button 4 is fully pressed all at once), for example, a moving object such as a subject running as shown in FIG. In many cases, the photographer desires to obtain a subject image at the timing when the photographer performs the full-press operation. Therefore, in such a case, the timing of the image capturing operation by the image sensor 23 is important.

  Therefore, in this embodiment, when the time interval between the half-press operation and the full-press operation of the shutter button 4 is relatively long, the subject distance is calculated from each block of the distance measuring unit 11 and the subject distance is used. The focus is adjusted roughly and then finely adjusted by the hill-climbing detection method (the external light passive method and the hill-climbing detection method are used in combination). In this way, the focus adjustment is performed in a short time compared with the case where the focus adjustment is performed by the hill-climbing detection method alone, and the focus is adjusted with higher accuracy than the case where the focus adjustment is performed by the outside light passive method alone. Adjustments can be made.

  In addition, when the time interval between the half-press operation and the full-press operation of the shutter button 4 is short, focus adjustment is performed by the external light passive method alone, and as shown in FIG. 13 regardless of the position of the main subject. In addition, focus adjustment is performed using the subject distance of the block located in the center of the distance measuring area AR2 of the distance measuring unit 11. In this way, an image close to the subject image desired by the photographer can be obtained as a recorded image. The reason for calculating the subject distance is the block located at the center because the main subject is often located at the center of the imaging range.

  However, when the FFP mode is set, focusing on the position designated as the focus position should be given the highest priority, so even if the time interval between the two operations on the shutter button 4 is short. The outdoor light passive method and the hill climbing detection method are used in combination. The external light passive focus adjustment performed here detects only the distance to the subject corresponding to the position specified by the cursor CSR in the distance measurement area AR2 of the distance measurement unit 11, and is performed based on the subject distance. Is.

  Accordingly, the AF control unit 49 determines that the AF control unit 49 sets the distance measurement unit 11 when the time interval between the half-pressing operation and the full-pressing operation of the shutter button 4 is relatively long when the FFP mode is not set. The hill-climbing detection using the contrast of the image composed of the pixel data output from the A / D conversion unit 31 after calculating the subject distance from each block and roughly adjusting the focus using these subject distances Adjust the focus according to the method.

  Further, when the time interval between the half-pressing operation and the full-pressing operation of the shutter button 4 is short when the FFP mode is not set, the AF control unit 49 is positioned at the center of the distance measuring area AR2 of the distance measuring unit 11. Using the subject distance of the block to be adjusted, the external light passive method alone performs focus adjustment.

  Further, when the FFP mode is set, the AF control unit 49 captures only the distance to the subject corresponding to the position specified by the cursor CSR in the distance measurement area AR2 of the distance measurement unit 11 from the block that captured the subject. After the detection and rough focus adjustment based on the subject distance, focus adjustment is performed by the hill-climbing detection method using the contrast of the image formed by the pixel data output from the A / D conversion unit 31. The AF control unit 49 corresponds to the evaluation unit, the first and second control units, and the setting unit in the claims.

  Returning to FIG. 8, the display control unit 50 transfers the image data of these images to the VRAMs 32 and 33 in order to display the live view image and the recorded image stored in the image storage unit 35 when the shooting mode is set. At the same time, when the playback mode is set, the image data in the image file stored in the image storage unit 35 is read and subjected to a predetermined expansion process, and the image indicated by the image data is reproduced and displayed on the display screen of the LCD 5. The image data is transferred to the VRAM 32.

  In addition, when the FFP mode is set, the display control unit 50 displays a cross-shaped cursor CSR superimposed on the display image as shown in FIG. 3, and according to the operation of the cross operation unit 6. The display position of the cursor CSR is changed.

  FIG. 14 is a flowchart showing a series of processing of the imaging apparatus 1. In addition, although the imaging device 1 of this embodiment can display an image on both LCD5 and EVF9, it shall display an image only on LCD5 here.

  As shown in FIG. 14, when the power of the imaging apparatus 1 is turned on (YES in step # 1), the main control unit 46 determines whether or not the photographing mode is set (step # 2). When the playback mode is set (NO in step # 2), the main control unit 46 performs a process of playing back and displaying the image stored in the image storage unit 35 on the LCD 5 (step # 3), and enters the shooting mode. When it is set (YES in step # 2), the display control unit 50 displays on the LCD 5 an image obtained by the image pickup operation of the image pickup device 23 performed on the image pickup device 23 at a predetermined cycle (for example, 1/30 second). It is displayed as a view image (step # 4).

  Then, the main controller 46 determines whether or not the FFP mode has been set by the push button 7 until the shutter button 4 is half-pressed (NO in step # 7, # 5). If the FFP mode is not set (NO in step # 5), the process proceeds to step # 7. On the other hand, if the FFP mode is set (YES in step # 5), the focus designation position is the push button 7. It is determined whether or not it has been determined by re-operation (step # 6). If the focus designation position has not been decided (NO in step # 6), the process returns to step # 5 and the focus designation position is decided. (YES in step # 6), the process proceeds to step # 7.

  In step # 7, the main control unit 46 determines whether or not the half-press operation of the shutter button 4 has been performed. If the half-press operation of the shutter button 4 has not been performed (NO in step # 7). Returning to step # 4, when the shutter button 4 is half-pressed (YES in step # 7), it is determined whether or not the FFP mode is set (step # 8).

  When the FFP mode is not set (NO in step # 8), the main control unit 46 causes the photometry unit 9 to perform a photometry operation (step # 9), and the AF control unit 49 starts with the distance measurement unit 11 first. The subject distance of the subject imaged by the block located at the center is calculated (step # 10). Then, the AF control unit 49 determines whether or not the shutter button 4 is fully pressed (step # 11), and when the shutter button 4 is fully pressed (YES in step # 11), The focus lens 20 is driven based on the subject distance obtained from the block located at the center (step # 12), and in this state, the image pickup device 23 performs an image pickup operation with the exposure control value derived by the photometry at step # 9. The image obtained by the imaging operation is stored in the image storage unit 35 (step # 22).

  On the other hand, if the shutter button 4 is not fully pressed in step # 11 (NO in step # 11), the AF control unit 49 starts calculating the subject distance of the subject imaged by another block. (Step # 13). Then, the AF control unit 49 determines again whether or not the shutter button 4 is fully pressed (step # 14), and when the shutter button 4 is fully pressed (YES in step # 14). The focus lens 20 is driven based on the subject distance calculated in step # 10 (step # 12), and the focus lens 20 is positioned at the position set in step # 12, and the photometry is performed in step # 9. The imaging device 23 is caused to perform an imaging operation with the derived exposure control value, and an image obtained by the imaging operation is stored in the image storage unit 35 (step # 22).

  In step # 14, when the shutter button 4 is not fully pressed (NO in step # 14), the AF control unit 49 does not finish calculating the subject distance for all blocks ( If NO in step # 15, the process returns to step # 13. When calculation of the subject distance is completed for all blocks (YES in step # 15), the main subject detection process is started (step # 16).

  If the shutter button 4 is fully pressed before the AF control unit 49 detects the main subject (NO in step # 17, YES in # 18), the subject distance calculated in step # 10 is used. When the focus lens 20 is driven (step # 12) and the focus lens 20 is positioned at the position set in step # 12, an image pickup operation is performed on the image sensor 23 with the exposure control value derived by the photometry in step # 9. The image obtained by the imaging operation is stored in the image storage unit 35 (step # 22).

  If the AF control unit 49 detects the main subject before the shutter button 4 is fully pressed (NO in step # 18, YES in # 17), the AF control unit 49 detects the subject distance of the detected main subject. Based on the above, the focus lens 20 is driven (step # 19).

  Thereafter, the AF control unit 49 performs focus adjustment by the hill-climbing detection method using the image of the main subject until the shutter button 4 is fully pressed (NO in step # 21) (step # 20), and the shutter button 4 is pressed (YES in step # 21), the image is taken with the exposure control value derived by photometry in step # 9 with the focus lens 20 positioned at the position set in step # 20. The element 23 is caused to perform an imaging operation, and an image obtained by the imaging operation is stored in the image storage unit 35 (step # 22).

  Regarding the processing of steps # 10 to # 22, the operation of fully pressing the shutter button 4 from the output of the distance measuring unit 11 until the main subject is detected includes half-pressing operation and full-pressing operation of the shutter button 4. Therefore, when the shutter button 4 is fully pressed in steps # 11, # 14, and # 18, the block located at the center of the distance measuring unit 11 is imaged. The outside light passive focus adjustment is performed based on the subject distance of the subject. In the present embodiment, the timing at which the main subject is detected corresponds to the predetermined timing in the claims.

  On the other hand, if the FFP mode is set in step # 8 (YES in step # 8), the main control unit 46 causes the photometry unit 9 to perform photometry operation (step # 24), and the AF control unit 49 Calculates the subject distance of the subject corresponding to the position of the cursor CSR determined in step # 6 (step # 25), and drives the focus lens 20 based on the calculated subject distance (step # 26). Thereafter, focus adjustment is performed by the hill-climbing detection method using the image of the subject corresponding to the position of the cursor CSR (step # 27). With the processing of steps # 25 to # 27, focusing at the position designated as the focus position has priority over the focusing time.

  Thereafter, when the shutter button 4 is fully pressed (YES in step # 21), the exposure derived by photometry in step # 24 with the focus lens 20 positioned at the position set in step # 27. The imaging element 23 is caused to perform an imaging operation with the control value, and an image obtained by the imaging operation is stored in the image storage unit 35 (step # 22).

  When the main control unit 46 and the like perform the storing process of the image in the image storage unit 35 by the full pressing operation of the shutter button 4, until the power of the imaging device 1 is turned off (NO in step # 23), When the process is repeated and the power is turned off (YES in step # 23), the series of processes is terminated.

  As described above, when the time interval between the half-press operation and the full-press operation of the shutter button 4 is relatively long when the FFP mode is not set, based on the subject distance calculated from each block of the distance measuring unit 11. Since the focus adjustment by the hill-climbing detection method is performed after the focus adjustment of the external light passive method, the focus adjustment in which the accuracy and time of the focus adjustment are compatible can be performed.

  When the time interval between the half-pressing operation and the full-pressing operation of the shutter button 4 is very short when the FFP mode is not set, the subject of the block located in the center in the distance measuring area AR2 of the distance measuring unit 11 is used. Since the focus adjustment is performed by the external light passive method alone using the distance, an image close to the subject image desired by the photographer can be obtained as a recorded image.

  Further, when setting the FFP mode, after performing the external light passive focus adjustment based on the distance to the subject corresponding to the position specified by the cursor CSR in the distance measurement area AR2 of the distance measurement unit 11, Since focus adjustment is performed by the hill-climbing detection method, it is possible to reflect the photographer's intention to focus at a position designated as a focus position, and the accuracy and time of focus adjustment are compatible. Focus adjustment can be performed.

  In addition to the first embodiment, or in place of the first embodiment, the present invention can employ modified embodiments described in the following embodiments (1) to (7).

  (1) In the first embodiment, when the time interval between the half-pressing operation and the full-pressing operation of the shutter button 4 is very short when the FFP mode is not set, the ranging area AR2 of the ranging unit 11 The focus adjustment is performed by the outside light passive method alone using the subject distance of the block located in the center, but the target block for calculating the subject distance is the center of the distance measurement area AR2 of the distance measurement unit 11 For example, as shown in FIG. 15 and FIG. 16, a target block for calculating the subject distance may be set.

  FIG. 15 illustrates a block B1 that is located in the center of the distance measurement area AR2 of the distance measurement unit 11 as a target block for calculating the subject distance, and is located on the same line sensor as the block B1. The block B2 and B3 which are separated by a predetermined interval are set.

  FIG. 16 shows a block B1 that is located in the center of the distance measurement area AR2 of the distance measurement unit 11 as a target block for calculating the subject distance, and is located on a line sensor different from the block B1. The block B4 and B5 arranged in the axial direction (see FIG. 4B, a direction orthogonal to the longitudinal direction of the line sensor) is shown.

  In this manner, the subject block for calculating the subject distance is focused on the main subject more reliably than in the first embodiment in which only the block located at the center of the distance measuring area AR2 of the distance measuring unit 11 is used. Can be taken together.

  That is, as a parameter for determining the main subject from a plurality of subjects, the subject distance (the subject with the smallest subject distance is set as the main subject) and the position in the shooting region (the one closest to the center of the shooting region is set as the main subject). 15), in FIG. 15, when the position in the shooting region is set to have priority over the subject distance, more appropriate focus adjustment can be performed as compared with the first embodiment. In FIG. 16, when the subject distance is set to have priority over the position in the shooting area, more appropriate focus adjustment can be performed as compared with the first embodiment.

  Note that the blocks for which the subject distance is calculated are not limited to those described above, and the number of blocks can be set as appropriate. In short, when the shutter button 4 is fully pressed, some blocks are determined in advance so that the focus adjustment operation can be performed quickly and the recording imaging operation can be performed, and the output of the block is used. What is necessary is just to perform the external light passive focus adjustment, and the block to be selected may be set to a block in an area where the possibility that the main subject is likely to exist is high.

  (2) In the first embodiment, when the FFP mode is not set and the time interval between the half-pressing operation and the full-pressing operation of the shutter button 4 is very short, focus adjustment by the hill-climbing detection method is not performed. However, the focus may not be accurately adjusted by not performing focus adjustment by the hill-climbing detection method. In consideration of this, when focus adjustment by the hill-climbing detection method is not performed and the subject brightness is a predetermined value or more, the depth of field is increased with respect to the exposure control value once derived from the subject brightness. It is advisable to make the aperture diameter of the stop small to compensate for insufficient focusing accuracy. In this case, for example, a subject luminance detecting unit that detects the subject luminance from the output of the image sensor 23 and an aperture control unit that controls the aperture diameter of the aperture are provided.

  Also, by reducing the aperture diameter of the aperture, it is possible to compensate for the shortage of exposure to the image sensor 23, so that the shutter speed is increased or the gain of amplification processing by the signal processing unit 24 (see FIG. 8) is increased. It is good to do.

  (3) In the first embodiment, the external light passive method according to the front-rear relationship between the timing at which the main subject is detected from the output of the distance measuring unit 11 and the timing at which the shutter button 4 is fully pressed. Whether to perform single focus adjustment or focus adjustment using both the external light passive method and the hill-climbing detection method is set, but not limited to this, the timing when the shutter button 4 is fully pressed is compared with the context The target timing may be the timing at which a predetermined time (minute time) has elapsed since the half-press operation of the shutter button 4 was performed.

  (4) In the hill climbing detection method, the position of the focus lens 20 is determined based on the contrast of the image. However, the present invention is not limited to this, and the position of the focus lens 20 is determined based on the spatial frequency of the image. May be.

  (5) The operation means for changing the display position of the cursor CSR is not limited to the configuration having the pressing portions 4a to 4d and the corresponding contacts provided as described above. It is also possible to have a configuration that includes a lever that can be swung 360 ° with a fulcrum as a fulcrum, and a detector that detects the inclination direction of the lever.

  (6) The ranging sensor unit 16 of the ranging unit 11 is configured by a plurality of line sensors (L1 to L14), but is not limited thereto, and may be configured by, for example, an area sensor. In this case, the present invention is applied similarly to the first embodiment by regarding the area sensor as a plurality of line sensors extending in the X direction shown in FIG. 4 and arranged adjacent to each other in the Y axis direction. be able to.

  (7) In the first embodiment, the photometric unit 10 is provided to detect the subject luminance. However, the photometric unit 10 is not provided, and the subject luminance is determined based on the outputs of the distance measuring unit 11 and the image sensor 23. The exposure control value may be determined based on the detected object brightness.

  The imaging apparatus 1 described above includes the inventions shown in the following supplementary notes 1 to 3 in addition to those described in the claims.

  [Supplementary Note 1] The predetermined timing is a timing for detecting a main subject having the highest importance among subjects within an imaging range of the imaging unit. Imaging device.

  According to the present invention, when the time interval between the operation of the first operation means and the operation of the second operation means is short, an image close to the subject image desired by the photographer can be obtained as a recorded image.

  [Appendix 2] The imaging apparatus according to any one of claims 1 to 6, wherein the predetermined timing is a timing when a predetermined time has elapsed from an operation timing of the first operation means.

  According to the present invention, when the time interval between the operation of the first operation means and the operation of the second operation means is short, an image close to the subject image desired by the photographer can be obtained as a recorded image.

  [Appendix 3] The image pickup apparatus according to any one of claims 1 to 7, wherein the first operation unit and the second operation unit are shutter buttons that perform the same type of operation with different operation amounts. .

  According to the present invention, the first operation unit for performing an input for instructing the imaging preparation operation for determining the control value related to the recording imaging operation, and the imaging unit is instructed to start the recording imaging operation. The present invention is particularly effective when the second operating means for performing input is also used as the same member (shutter button).

It is a front view which shows the structure of the imaging device which concerns on this invention. It is a rear view of an imaging device similarly. (A) is a figure which shows the cursor displayed superimposed on an image on the display screen of LCD or EVF, (b) is a figure which shows a mode that the cursor moves. (A) is sectional drawing which shows the internal structure of a ranging part, (b) is a figure which shows the structure of the ranging sensor part in a ranging part when it sees from the arrow Q in (a). It is a figure which shows the relationship between an imaging range and the ranging area of a ranging part when a zoom lens is located in a wide end position. It is the figure which showed the relationship between the imaging | photography area | region when a zoom lens is located in a wide end position and a tele end position, and the ranging area of a ranging part. FIG. 6 is a diagram illustrating a relationship among an imaging range, a distance measurement unit, and a distance measurement area when the zoom lens is driven from the wide angle side to the telephoto side from the state illustrated in FIG. 5. It is a block diagram which shows the structure of an imaging device. It is a figure for demonstrating the principle of the ranging calculation by an external light passive system (triangular ranging system). It is a figure for demonstrating the principle of the ranging calculation by an external light passive system (triangular ranging system) similarly. It is a figure for demonstrating the principle of the ranging calculation by an external light passive system (triangular ranging system) similarly. It is a figure which shows the relationship between the position of the focus lens in an optical axis direction, and contrast. It is a figure for demonstrating the focus adjustment method when the time interval of half-pressing operation of a shutter button and full-pressing operation is very short. It is a flowchart which shows a series of processes of an imaging device. It is a figure which shows the modification of this invention. It is a figure which shows the modification of this invention.

Explanation of symbols

2 Imaging optical system 4 Shutter button (first operation means, second operation means)
5 LCD
6 Cross operation section 7 Push button 11 Distance measuring section (ranging means)
14, 15 Ranging optical system 16 Ranging sensor units 17, 18 Line sensor groups L1 to L14 Line sensor 19 Zoom lens 20 Focus lens (focus adjusting means)
L1, La, Lb Optical axis 23 Imaging element (imaging means)
48 mode setting section 49 AF control section (evaluation means, first control means, second control means, setting means)

Claims (6)

Imaging means for imaging a light image of a subject by photoelectric conversion;
An imaging optical system that includes a focus adjustment unit for focusing the focal position of the imaging lens on the imaging surface of the imaging unit, and forms a subject image on the imaging surface of the imaging unit;
Evaluation means for evaluating the clarity of an image obtained by the imaging operation of the imaging means;
A pair of distance measuring optical systems, and an external light passive type distance measuring means having a plurality of distance measuring sensors provided corresponding to each distance measuring optical system and having a plurality of distance measuring points;
First control means for causing the focus adjusting means to perform a focusing operation using the subject distance detected by the distance measuring means;
Second control means for causing the focus adjusting means to perform a focusing operation using the subject distance detected by the distance measuring means and the evaluation by the evaluating means;
A first operating means for performing an input for instructing an imaging preparation operation for determining a control value related to the recording imaging operation;
A second operating means for performing an input for instructing the imaging means to start the recording imaging operation;
When the operation of the second operation means is performed from the operation timing of the first operation means to a predetermined timing, the subject distance obtained from a predetermined partial area of the distance measurement area of the distance measurement means is determined. The second control means when the first control means is caused to execute control for causing the focus adjusting means to perform a focusing operation using the first control means, and the second control means is not operated by the predetermined timing. An imaging apparatus comprising: setting means for executing control by the means.   The imaging apparatus according to claim 1, wherein the predetermined partial area is a distance measuring point located in a center part of a distance measuring area of the distance measuring means.   The distance measuring sensor is configured by two-dimensionally arranging a plurality of pixels that photoelectrically convert an optical image of a subject in two intersecting directions, and the predetermined partial area is defined by the distance measuring means. It is an area composed of a center distance measuring point in the distance measuring area and one or a plurality of distance measuring points arranged in one of the two directions with respect to the center distance measuring point. The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized.   The second control unit causes the focus adjustment unit to perform a focusing operation using the subject distance detected by the distance measurement unit, and then focuses the focus adjustment unit using the evaluation by the evaluation unit. The imaging apparatus according to claim 1, wherein an operation is performed.   A diaphragm for adjusting a light amount of a light image of a subject led to the imaging unit; a diaphragm control unit for controlling an aperture diameter of the diaphragm; and a subject luminance detection unit for detecting the luminance of the subject. When the control by the control means is performed and the brightness of the subject detected by the subject brightness detection means is greater than a predetermined brightness, the aperture control means performs a process of reducing the aperture diameter of the stop. The imaging device according to claim 1.   A mode setting means for setting in a focus manual setting mode capable of inputting an in-focus point from an imaging region of the image pickup means, and an operation means for performing an input specifying the in-focus point, When the mode setting unit sets the in-focus manual setting mode, the setting unit performs focusing using at least the evaluation by the evaluation unit regardless of the operation time interval with respect to the first and second operation units. The imaging apparatus according to claim 1, wherein the focus adjustment unit performs an operation.

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