JP6924306B2 - Image blur correction device and its control method, program, storage medium - Google Patents

Description

The present invention relates to a technique for correcting out-of-focus caused by driving a shift lens in image blur correction in an image pickup apparatus.

In recent years, the optical system of image pickup devices such as still cameras and video cameras has been increasing in magnification, and on the telephoto side, image blurring due to shaking applied to the image pickup device such as camera shake has become more noticeable. , Further performance improvement is required. The image stabilization mechanism detects the camera shake of the photographer and drives a part of the lens (shift lens) that constitutes the imaging optical system in a direction substantially orthogonal to the optical axis, and is an image caused by the camera shake of the photographer. It is a mechanism to cancel the blur. That is, in order to cancel the image blur caused by camera shake, the shift lens operates to deviate from the optical axis of the entire optical system. As described above, in order to meet the demand for improving the image stabilization performance of the image stabilization mechanism, it is necessary to move the shift lens significantly, so that the shift lens deviates further from the optical axis.

On the other hand, in recent years, the number of pixels in an imaging device has increased, and even a slight defocusing is easily noticeable, and more accurate focusing is required. As a means for focusing, there is a triangular distance measuring method in which an external distance measuring sensor is mounted to measure the distance to the subject and focus on the subject. As another means, there is a contrast AF method in which an AF (autofocus) evaluation value obtained by extracting a specific frequency component of a luminance signal obtained from an image sensor is used for automatic focus adjustment. Furthermore, in order to reduce the effect of camera shake on focusing accuracy, the first focusing position by the triangular distance measurement method and the second focusing position by the contrast AF method are weighted according to the degree of camera shake. There is a technique of changing the focus position to a third focus position (Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-145852

However, if the shift lens is driven so as to deviate significantly from the optical axis, the subject contrast in the center of the image is lowered and the optical performance is lowered. In the contrast AF method, in the through image before the start of exposure, the focus lens is driven to a position where the contrast of the subject becomes high in order to focus on a predetermined subject, and once the subject is in focus, the focus lens maintains that position. It will be. However, even when the subject is in focus, if the camera shakes due to camera shake of the photographer or the like, the shift lens moves to detect the shake in the camera and cancel the shake.

At this time, if the shift lens is largely deviated from the optical axis, the contrast of the subject in the center of the image is lowered and the through image is in a so-called out-of-focus state, which causes discomfort to the photographer. Further, when the exposure to the image sensor is started, the focus lens is not driven and is fixedly held during the exposure. However, since the camera shake is detected in the camera during exposure to drive the shift lens, the captured image may be exposed with the contrast of the subject lowered.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an image blur correction device that suppresses deterioration of the image quality of a captured image while providing a necessary image blur correction effect. be.

The image blur correction device according to the present invention moves in a direction orthogonal to the optical axis of the image pickup optical system to optically correct the image blur of the subject image due to the shake of the image pickup device, and captures the subject image on the screen of the image pickup means. The drive control means for driving the image blur correction means to be moved above, and the image blur correction for optically correcting the image blur in conjunction with the operation of the image blur correction means during the exposure period for moving images. The focus control means includes a focus control means for controlling the focus lens to be driven in the optical axis direction of the imaging optical system in order to adjust the focus shift of the subject image caused by driving the means. During the exposure of the imaging means, the driving amount of the focus lens is limited.

According to the present invention, it is possible to provide an image blur correction device that suppresses deterioration of the image quality of a captured image while providing a necessary image blur correction effect.

The figure which shows the whole structure of the lens in 1st Embodiment of this invention. The figure which shows the whole structure of the lens in 1st Embodiment of this invention. The figure which shows the whole structure of the lens in 1st Embodiment of this invention. The detailed view of the zoom drive part of the lens in 1st Embodiment of this invention. A front view and a cross-sectional view of a two-group unit according to the first embodiment of the present invention. The development view of the 3 group unit in 1st Embodiment of this invention. The block diagram of the image pickup apparatus in the 1st Embodiment of this invention. The figure which showed the decrease of the subject contrast by the movement of a shift lens. The figure which showed the relationship of the focus lens correction amount with respect to the movement amount of a shift lens. The flowchart which shows the correction operation of the focus in 1st Embodiment. The flowchart which shows the correction operation of the focus in 2nd Embodiment.

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

(First Embodiment)
1 to 3 are views showing the overall configuration of a lens (imaging optical system) 200 in the imaging device according to the first embodiment of the present invention. In FIGS. 1 to 3, the lens 200 for forming a subject image in the present embodiment is composed of three lens groups. Specifically, it includes a group 1 unit composed of a group 1 lens holding frame 11 that holds the first lens group 1 and a group 1 base plate 12 that includes a lens barrier member that holds the group 1 lens holding frame 11 and protects the lens. .. Further, a second group unit consisting of an aperture unit 21 which is a light amount adjusting member at the time of shooting, a second group lens holding frame 31 for holding the second lens group 2, and a second group base plate 32 including a shutter member (not shown), and a third lens. A three-group unit including a three-group lens holding frame 41 for holding the group 3 is further provided. The 1st group unit, the aperture unit, and the 2nd group unit are variable magnification lens groups. The 2nd group unit (shift lens) is equipped with an image stabilization mechanism, and the 2nd group lens holding frame 31 moves in a direction substantially orthogonal to the optical axis during shooting, so that on the screen due to camera shake during shooting or the like. Correct image blur. The third lens group 3 is a focus lens group for focusing on the subject.

FIG. 1 shows a retracted state in which the lens group is in the retracted state in the shooting standby state, and FIG. 2 shows the 1st group lens holding frame 11, the 2nd group lens holding frame 31, and the 3rd group lens holding frame 41 in the optical axis direction. Shows the shooting state that has been extended to. The sensor holder unit 500 includes a sensor holder 501, a third lens group 3, and an image sensor 5. An image sensor 5 is supported by the sensor holder 501 via a sensor plate 505, and an optical filter 4 is arranged in front of the image sensor 5 between the sensor holder 501 and a sensor rubber (not shown). As shown in the perspective view of FIG. 3, the lens barrel in the present embodiment is formed as one lens barrel by fastening the fixed cam ring 504, which is a component constituting the zoom mechanism, and the sensor holder unit 500 with screws. ing.

As shown in FIGS. 3 and 4, a zoom motor 601 and gear rows 603 to 606 are arranged in the sensor holder 501. A gear 602 is attached to the drive shaft of the zoom motor 601. The gear 602 is rotated by the driving force of the zoom motor 601 and transmitted to the lens barrel member via the gear trains 603 to 606. As a result, the lens barrel is driven straight in the direction along the optical axis. Each of the gears of the gear rows 603 to 606 is a stepped gear having a large-diameter gear and a small-diameter gear having different numbers of teeth coaxially. The final gear 606 that meshes with the moving cam ring 503 is also a stepped gear, and includes a large-diameter gear portion and a small-diameter gear portion that is long in the direction along the optical axis.

Next, a tubular member and a zoom drive mechanism for moving each lens group in the optical axis direction will be described. As shown in FIGS. 1 and 2, a moving cam ring 503 is arranged on the outer circumference of each lens group. As shown in FIG. 3, three types of cam grooves 503a, 503b, and 503c having different trajectories are formed on the inner circumference of the moving cam ring 503. Then, the follower pins 12a, 21a, 32a formed on the outer periphery of the first group ground plate 12, the drawing unit 21, and the second group ground plate 32 are engaged with each cam groove to follow the movement of the moving cam ring 503. It is configured so that it can be done.

Further, as shown in FIGS. 1 to 3, a straight guide cylinder 502 for restricting rotation when each lens group moves is provided on the inner circumference of the moving cam ring 503. The straight guide cylinder 502 and the moving cam ring 503 are so-called bayonet-coupled and move substantially integrally in the direction along the optical axis, and the moving cam ring 503 becomes relatively rotatable with respect to the straight guide cylinder 502. There is. As shown in FIG. 3, the straight guide cylinder 502 is provided with elongated grooves 502a, 502b, 502c extending in the direction along the optical axis. The first group base plate 12, the diaphragm unit 21, and the second group base plate 32 move straight in the direction along the optical axis by being restricted in rotation by the long grooves 502a, 502b, and 502c.

A cam groove 504a and a straight guide groove 504b, which is a linear groove, are formed on the inner circumference of the fixed cam ring 504. As shown in FIG. 3, the follower pin 503d formed on the outer circumference of the moving cam ring 503 can engage with and follow the cam groove 504a. Further, the guide groove 504b is slidably fitted with the straight-moving restricting portion 502d of the straight-moving guide cylinder 502. A gear portion 503e is formed on the outer periphery of the moving cam ring 503 as shown in FIG. Then, the zoom motor 601 starts driving, and the driving force is transmitted from the final gear 606 of the gear trains 603 to 606 to the gear portion 503e of the moving cam ring 503 to perform the rotation operation. As a result, the moving cam ring 503 rotates about the optical axis while engaging with and following the cam groove 504a formed on the inner circumference of the fixed cam ring 504, and moves straight in the direction along the optical axis.

The gear portion 503e of the moving cam ring 503 meshes with a small diameter gear that is a part of the final gear 606. The large-diameter gear of the final gear 606 is located rearward (on the image sensor side) along the optical axis with respect to the small-diameter gear, and meshes with the gear 605. The long gear portion of the final gear 606 is formed long in the direction along the optical axis in accordance with the amount of extension of the moving cam ring 503 so as to correspond to the movement of the moving cam ring 503 in the direction along the optical axis. The straight guide cylinder 502 moves integrally with the moving cam ring 503 in the direction along the optical axis. However, since the straight guide portion 502d of the straight guide cylinder 502 is slidably fitted in the straight guide groove 504b of the fixed cam ring 504, the rotation is restricted, so that the straight guide cylinder 502 moves only in the straight direction.

With such a configuration, the moving cam ring 503 rotates, so that the first group unit, the aperture unit 21, and the second group unit following the moving cam ring 503 move straight in the direction along the optical axis while the rotation is restricted. do. As shown in FIGS. 1 to 3, the fixed cam ring 504 is fastened to the sensor holder 501 with screws and is integrally formed, so that the fixed cam ring 504 does not move in the direction along the optical axis or in the rotation direction.

Next, FIG. 5 is a diagram showing a configuration of an image blur correction device, FIG. 5 (a) is a front view of the group 2 unit as viewed from the subject side, and FIG. 5 (b) is a lens of FIG. 5 (a). It is a cross-sectional view when cut at the center. The image blur correction device will be described with reference to FIG.

In FIG. 5, the outer peripheral side of the second group base plate 32 is composed of a magnet 37 and a coil 38, and holds the second group lens 2 as a shift lens (optical member), which will be described in detail later. A lens driving unit for moving 31 in a direction orthogonal to the optical axis is provided. A shutter drive unit (not shown) for driving the shutter mechanism is provided on the outer peripheral side of the second group lens 2 of the second group base plate 32, and an ND (not shown) for driving the ND filter is provided on the image plane side of the second group base plate 32. A drive unit is provided.

Further, the second group lens holding frame 31 and the second group base plate 32 are connected in a direction along the optical axis by two tension springs (not shown). The urging force of the two tension springs urges the second group lens holding frame 31 with respect to the second group base plate 32 with the ball 35 sandwiched in the direction along the optical axis. Then, the rolling of the ball 35 causes the second-group lens holding frame 31 that holds the second-group lens 2 to move in a direction orthogonal to the optical axis.

A Hall element holding portion 34 is arranged on the subject side of the second group ground plate 32. Then, the shutter FPC (flexible printed circuit) 33 is crawled over the Hall element holding unit 34 in a state of being connected to the lens driving unit, the shutter driving unit, and the ND driving unit, and the outer periphery of the Hall element holding unit 34 is laid. It is pulled out to the image plane side along the pull-out surface of the part. Hall elements 36 for detecting the position of the second lens group 2 are mounted on the shutter FPC 33 at two locations separated from each other by 90 ° in the circumferential direction. The Hall element 36 is electrically connected to a lens barrel FPC (not shown) via a shutter FPC 33. The shutter FPC 33 is fixed to the Hall element holding portion 34, and the Hall element holding portion 34 is locked to the second group base plate 32 by a snap-fit coupling with the second lens group 2 sandwiched between them.

The second group lens holding frame 31 is provided with a magnet 37 magnetized so as to sandwich the Hall element 36 between the N pole and the S pole, and outputs a magnetic field passing through the magnet 37 to the output of the two Hall elements 36. The control unit of the camera body detects from. When the 2nd group lens holding frame 31 moves in a plane orthogonal to the optical axis, the magnetic field passing through the Hall element 36 changes and the output of the Hall element 36 changes, so that the 2nd group lens holding frame 31 is orthogonal to the optical axis of the 2nd group lens holding frame 31. The position in the direction can be detected (drive amount detection).

Further, a coil 38 is arranged at a position facing the magnet 37 on the image plane side in the optical axis direction, and the coil 38 is attached to the second group base plate 32. The coil 38 is electrically connected to a lens barrel FPC (not shown) via the shutter FPC 33, whereby power is supplied from the power supply unit of the camera body. Then, when the coil 38 is energized, an electromagnetic force is generated, and the second group lens holding frame 31 can be driven in a direction orthogonal to the optical axis.

Next, the configuration of the focus drive mechanism attached to the sensor holder unit 500 will be described with reference to FIGS. 3 and 6. A group 3 lens holding frame 41 is supported on the sensor holder 501 so as to be movable in the optical axis direction. That is, as shown in FIGS. 3 and 6, the main guide shaft 42 parallel to the photographing optical axis is press-fitted into the hole of the sensor holder 501 and fixed, and the sub-guide shaft 43 for rotation regulation is the same as the main guide shaft 42. Is press-fitted into the hole of the sensor holder 501 and fixed.

As shown in FIG. 6, the focus drive motor 44 is fastened and fixed to the sensor holder 501 with screws. A sleeve 41a is formed on the group 3 lens holding frame 41. The sleeve 41a is formed with a sleeve hole that engages with the main guide shaft 42. Further, the group 3 lens holding frame 41 is formed with a U-shaped groove 41b that engages with the sub guide shaft 43. Further, the group 3 lens holding frame 41 is provided with a support hole 41c for supporting the rack 45 in the vicinity of the sleeve 41a.

The rack 45 includes meshing teeth 45a that mesh with a lead screw 44a integrally formed on the motor output shaft, and urging teeth 45b that face the meshing teeth 45a. Further, the rack 45 is formed with a support shaft that engages with the support hole 41c of the group 3 lens holding frame 41. The urging tooth 45b is pressed by the arm portion of the torsion coil spring 46 in a direction in which it meshes with the lead screw 44a, and the arm portion of the torsion coil spring 46 is hooked on the back surface portion of the rack 45. As a result, the lead screw 44a is sandwiched between the urging tooth 45b and the meshing tooth 45a, and the urging tooth 45b and the meshing tooth 45a are always in mesh with the lead screw 44a.

Further, the torsion coil spring 46 also urges the rack 45 toward the end face of the third group lens holding frame 41 in the optical axis direction to prevent rattling between the rack 45 and the third group lens holding frame 41. It is designed so that it can be driven stably and with high accuracy in the optical axis direction. In such a configuration, when the lead screw 44a of the focus drive motor 44 rotates, the group 3 lens holding frame 41 advances and retreats linearly in the direction along the optical axis due to the screwing relationship between the rack 45 and the lead screw 44a.

FIG. 7 is a block diagram showing a configuration example of the digital camera 100. Here, the configuration in which the camera body and the lens 200 are integrated is shown, but the lens 200 may be interchangeably configured with respect to the camera body. In FIG. 7, the lens 200 holds a lens group inside the lens 200 to drive the lens. The lens 200 in FIG. 7 is the lens 200 shown in FIGS. 1 to 6, but is shown in FIG. 7 in a simplified manner in order to make the configuration easy to understand. The first lens group (zoom lens group) 1 optically changes the angle of view by adjusting the focal length. The second lens group 2 is a shift lens that can move in a direction different from the optical axis, and corrects image blur. The third lens group (focus lens group) 3 adjusts the focus position. The aperture and shutter 105 adjust the amount of light for exposure control. As shown in FIGS. 1 to 6, the actual aperture 21 is arranged between the first lens group 1 and the second lens group 2, and the shutter is arranged between the second lens group and the third lens group. Has been done. However, in FIG. 7, the aperture 21 and the shutter are collectively shown as the aperture and the shutter 105 for the sake of clarity.

The light that has passed through the lens 200 is received by an image pickup device 106 that uses a CCD (charge-coupled device), a CMOS (complementary metal oxide semiconductor) sensor, or the like, and is converted from an optical signal into an electric signal. The electric signal is input to the image processing circuit 107, subjected to pixel interpolation processing, color conversion processing, and the like, and then sent to the internal memory 108 as image data.

The display unit 109 displays shooting information and the like together with the shot image data. The compression / decompression processing unit 110 compresses and decompresses the data stored in the internal memory 108 according to the image format. The storage memory 111 stores various data such as parameters. The operation unit 112 is a user interface for performing various menu operations and mode switching operations. For example, the operation unit 112 can switch between a still image and a moving image, and switch between manual focus and autofocus by a user's operation.

The shake detection unit 113 detects the shake applied to the image pickup apparatus and the shake. The aperture shutter drive unit 114 drives the aperture and the shutter 105. The luminance signal calculation unit 121 calculates the electrical signal output from the image sensor 106 as the luminance of the subject. The exposure control unit 120 calculates the exposure control value (aperture value and shutter speed) based on the brightness information obtained by the brightness signal calculation unit 121.

The focus lens driving unit 115 drives the third lens group (focus lens) 3. The focus control unit (focus lens control unit) 123 controls the drive direction and drive amount of the focus lens 3. The scanning control unit 124 issues a drive command in a predetermined range to the focus control unit 123, and at the same time, refers to an evaluation value (output signal) which is a calculation result of the evaluation value calculation unit 122 at a predetermined position of the focus lens 3. Calculate the shape of the contrast. Automatic focusing (AF) control is performed with the focus position (focus detection result) at which the contrast is highest as the position where the light flux is focused on the 106 surface of the image sensor.

The shift lens driving unit 116 drives the shift lens 2. The shift lens current position detection unit 117 acquires the current position of the shift lens 2. The image blur correction control unit (shift lens drive control unit) 125 calculates the movement direction and movement amount of the shift lens 2 for canceling the image blur caused by the shake of the imaging device based on the information of the shake detection unit 113. do. Image blurring is canceled by driving the shift lens 2 based on this calculation result. The focus correction unit 126 corrects the position of the focus lens 3 according to the position of the shift lens 2.

The zoom lens driving unit 118 drives the first lens group (zoom lens group) 1. The zoom control unit 127 controls the drive direction and drive amount of the zoom lens group 1 according to the zoom operation instruction by the operation unit 112. The system control unit 119 is composed of an arithmetic unit such as a CPU (central processing unit), and various control programs stored in the internal memory 108 according to the user's operation, such as AE control, AF control, and image blur correction control. , Execute a program for zoom control, etc.

The operation unit 112 is provided with a release button that turns on the first switch (SW1) and the second switch (SW2) in order according to the amount of pushing. Here, when the release button is pushed about halfway, the first switch SW1 is turned on, and when the release button is pushed all the way, the second switch SW2 is turned on. When the first switch SW1 is turned on, the exposure control unit 120 calculates the exposure control value (aperture value and shutter speed) based on the brightness information obtained by the luminance signal calculation unit 121, and drives the aperture shutter with the calculation result. Notify section 114. As a result, automatic exposure (AE) control is performed. The evaluation value calculation unit 122 calculates the AF evaluation value after extracting a specific frequency component from the luminance signal calculated by the luminance signal calculation unit 121.

When the second switch SW2 of the release button is turned on, the exposure control unit 120 takes a picture based on the determined aperture value and the shutter speed, and stores the image data obtained by the image sensor 106 in the storage memory 111. do. Further, when displaying a so-called live view image obtained in a state where the release switch is not pressed, the exposure control unit 120 prepares for the still image shooting exposure at predetermined intervals and the brightness related to the above-mentioned video signal. Preliminarily determine the aperture value and shutter speed based on the information and the program diagram.

Here, the out-of-focus of the subject that occurs when the shift lens, which is a feature of the optical system having an image blur correction function, deviates from the optical axis will be described with reference to FIG. In FIG. 8, the X-axis represents the position of the focus lens, the Y-axis represents the evaluation value of the contrast of the subject, and the position of the focus lens with respect to a predetermined subject and the fluctuation of the contrast evaluation value of the subject are shown. ..

As shown in FIG. 8, the contrast evaluation value of the subject changes depending on the position of the focus lens 3, and a mountain shape is formed due to the difference in contrast. The apex of the mountain is the position where the contrast of the subject is maximized, and when the focus lens 3 is arranged at this position, it is in focus.

8 (a) and 8 (b) show that when the shift lens 2 is on the same optical axis as the other lens group, FIGS. 8 (c) and 8 (d) show that the shift lens 2 is the other lens group. It shows the contrast evaluation value of the subject and the position of the focus lens when the lens is located off the center of the optical axis. 8 (b) is a schematic view showing the case where the shake correction lens is on the same optical axis as the other lens groups, and FIG. 8 (d) is the shake correction lens deviating from the center of the optical axis composed of the other lens groups. It is a schematic diagram which shows the case of being in a position.

When the shift lens is on the optical axis as shown in FIG. 8 (b), it can be seen that the contrast evaluation value becomes the maximum value when the focus lens is in the X1 position as shown in FIG. 8 (a). .. When the shift lens 2 is driven from this state and deviates from the center of the optical axis as shown in FIG. 8 (d), the relationship between the contrast evaluation value of the subject and the position of the focus lens becomes the state of FIG. 8 (c). At this time, the mountain shape of the contrast evaluation value of the subject shifts to the right as shown in FIG. 8C. That is, the focus lens position at which the contrast evaluation value of the subject is maximized shifts from X1 to X2.

It is assumed that when the shift lens 2 is positioned on the optical axis composed of other lens groups, the focus lens 3 moves to move to the position of X1 and stops at the position of X1 to focus on the subject. From that state, if the shift lens 2 is moved and the focus lens 3 is left at the position of X1, the contrast evaluation value of the subject is deviated and the position is lowered from Y1 to Y2 as shown in FIG. 8C. In this state, the shooting operation is performed with the contrast evaluation value low. Furthermore, since the camera shake of the photographer is not constant and changes from moment to moment, the movement of the shift lens is not constant, and the subject contrast is constantly changing.

Next, the operations of the shift lens 2 and the focus lens 3 before and after shooting in the present embodiment to solve the above problems will be described. FIG. 9 is a diagram showing the relationship between the correction amount of the shift lens position and the focus lens position.

The Y-axis represents the position of the shift lens 2 from the optical axis, and the X-axis represents the amount of correction of the position of the focus lens 3 to be corrected when the shift lens 2 is driven. When the position of the shift lens 2 is 0, that is, at the center of the optical axis, the position of the shift lens 2 is represented by Mov0 in FIG. When the position of the shift lens 2 is Mov0, the correction amount of the focus position is Comp0. As a specific numerical value, Mov0 is zero, and Comp0 is also zero.

On the other hand, when the position of the shift lens 2 is farthest from the center of the optical axis, the position of the shift lens 2 is represented by Mov5 in FIG. When the position of the shift lens 2 is Mov5, the correction amount of the position of the focus lens 3 is Comp5. In this way, the relationship between the movement amount of the focus lens 3 and the position of the shift lens 2 is stored in the internal memory 108. Therefore, when shooting a predetermined subject, the contrast of the subject on the live view image is lowered by moving the focus lens 3 by an amount corresponding to the amount of camera shake (movement amount of the shift lens 2) of the photographer. There is no.

Each numerical value including Mov5 and Comp5 is a numerical value that changes depending on the characteristics of the optical system. Further, in FIG. 9, the relationship between the position of the shift lens 2 and the correction amount of the position of the focus lens 3 is a straight line, but this may also change to a curved line depending on the characteristics of the optical system.

As described above, in the present embodiment, the correction amount of the position of the focus lens 3 corresponding to the movement amount of the shift lens 2 is stored in the internal memory 108. However, if the focus lens 3 is driven as the shift lens 2 moves during still image exposure, the angle of view may fluctuate and the peripheral image quality may deteriorate. In consideration of such a case, the system control unit 119 can limit the amount of movement of the focus lens 3 by the length of the still image exposure time.

Similarly, when the focus lens is driven as the shift lens 2 moves during movie shooting, the angle of view may change, causing discomfort to the user. Therefore, it is possible to prevent sudden fluctuations in the angle of view by setting a limit on the movement amount and movement speed of the focus correction by the focus lens 3 at the time of moving image shooting.

Further, when the focus lens 3 is driven as the shift lens 2 moves, the power consumption increases and the number of shots decreases. Therefore, when the amount of movement of the shift lens 2 is small and the focus fluctuation is small, it is possible to intentionally not drive the focus lens 3 or limit the amount of drive.

Further, when the user selects the manual focus mode, it is possible to select a mode in which the focus lens 3 is driven as the shift lens 2 moves and a mode in which the focus lens 3 is not driven. This makes it possible to provide the user with a degree of freedom in shooting.

FIG. 10 is a flowchart for explaining a process for driving the focus lens based on the movement of the shift lens in shooting with a camera. The process based on the flowchart of FIG. 10 is performed under the control of the system control unit 119.

First, when the power of the camera is turned on in S101, in S102, the system control unit 119 starts image blur correction control according to the amount of camera shake by the photographer. In S103, the focus correction control of the focus lens 3 is started according to the correction amount of the shift lens 2. In S104, it is determined whether or not the second switch (SW2) of the release button is pressed. If the second switch (SW2) is not pressed in S104, the screen returns to S102 with the live view image displayed, and the operations of S103 and S104 are repeated.

On the other hand, when the second switch (SW2) is pressed in S104, the still image shooting operation is started in S105 and the exposure is started. In S106, the shift lens 2 is driven by the system control unit 119 for image blur correction according to the amount of camera shake even during exposure. When the exposure is started, the process proceeds to S111 assuming that the image is in the shooting state, and the system control unit 119 starts the movement of the focus lens 3 in conjunction with the movement of the shift lens 2 to perform the focus correction operation. After that, the process proceeds to S112, and the exposure ends.

(Second Embodiment)
Next, a second embodiment of the image pickup apparatus of the present invention will be described. Since the configuration of the image pickup apparatus of the second embodiment is the same as that of the first embodiment, only the parts different from the first embodiment will be described in this second embodiment. In the second embodiment, the movement operation of the shift lens and the focus lens during subject exposure is different from that in the first embodiment.

FIG. 11 is a flowchart for explaining a process for driving the focus lens based on the movement of the shift lens in shooting with a camera. The process based on the flowchart of FIG. 11 is performed under the control of the system control unit 119.

First, when the power of the camera is turned on in S201, in S202, the system control unit 119 starts the image blur correction control according to the amount of camera shake by the photographer. In S203, the focus correction control of the focus lens 3 is started according to the correction amount of the shift lens 2. In S204, it is determined whether or not the second switch (SW2) of the release button is pressed. If the second switch (SW2) is not pressed in S204, the screen returns to S202 with the live view image displayed, and the operations of S203 and S204 are repeated.

On the other hand, when the second switch (SW2) is pressed in S204, the still image shooting operation is started in S205, and the exposure is started. In S206, the shift lens 2 is driven by the system control unit 119 for image blur correction according to the amount of camera shake even during exposure. When the exposure is started, the system control unit 119 determines in S207 whether or not the calculated exposure time is within a predetermined time, assuming that the image is in the shooting state. If the exposure time in S207 is longer than a predetermined time, the process proceeds to S208, and the system control unit 119 limits or does not move the movable range of the focus correction of the focus lens 3. After that, the process proceeds to S212, and the exposure ends.

When the exposure time is within a predetermined time in S207, the system control unit 119 determines in S209 whether or not the calculated movement amount of the focus lens 3 is within the predetermined amount. If the amount of movement of the focus lens 3 is within a predetermined amount in S209, the process proceeds to S210, and the system control unit 119 limits the movement range or drive speed of the focus lens, or does not move the focus lens 3. After that, the process proceeds to S212, and the exposure ends.

On the other hand, when the movement amount of the focus lens 3 is larger than the predetermined amount (predetermined threshold value) in S209, the process proceeds to S211 and the system control unit 119 starts the movement of the focus lens 3 in conjunction with the movement of the shift lens 2. The focus correction operation is performed. After that, the process proceeds to S212, and the exposure ends.

As described above, in the present embodiment, the operation of limiting the movement amount of the focus lens according to the exposure time has been described, but it may not be necessary to limit the movement amount of the focus lens depending on the optical system. Therefore, the operation of the present invention is not limited to the flowchart of FIG.

Although the above description has been made by taking an image pickup apparatus as an example, the present invention is not limited to these embodiments, and various forms within the range not deviating from the gist of the present invention are also included in the present invention.

For example, in the above embodiment, focus correction is performed by the focus lens in conjunction with the movement of the shift lens during exposure, but in consideration of deterioration of peripheral image quality due to angle of view fluctuation due to movement of the focus lens, focus is performed during exposure. You may control the lens so that it does not move.

Further, although the zoom lens in the above embodiment is a lens barrel having a three-group configuration, it does not have to be a three-group configuration. Further, although the shift lens is one lens group, the present invention can also be applied when image blur correction is performed by two shift lens groups (plural arrangements). In that case, the focus correction amount of the focus lens may be calculated from the correction amounts of the two shift lens groups.

Further, it is not the lens but the image sensor that corrects the image blur, and the image sensor may move in a plane orthogonal to the optical axis.

In addition to the form in which the shift lens moves in a plane orthogonal to the optical axis, the lens may be tilted with an arbitrary central axis on the optical axis as the rotation axis.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

100: Digital camera, 1: 1st lens group, 2: 2nd lens group (shift lens), 3: 3rd lens group (focus lens group), 106: image sensor

Claims (12)

Drives an image blur correction means that moves the subject image on the screen of the image pickup means by moving in a direction orthogonal to the optical axis of the imaging optical system so as to optically correct the image blur of the subject image due to the shake of the image pickup device. Drive control means and
During the exposure period for moving images, the focus shift of the subject image caused by driving the image blur correction means to optically correct the image blur is adjusted in conjunction with the operation of the image blur correction means. Therefore, a focus control means for controlling the focus lens to be driven in the optical axis direction of the imaging optical system is provided.
The focus control means is an image blur correction device that limits the amount of drive of the focus lens during exposure of the image pickup means. The shake detecting means for detecting the shake of the image pickup apparatus is further provided, and the drive control means drives the image blur correcting means so as to correct the image blur of the subject image based on the output of the shake detecting means. The image blur correction device according to claim 1. The drive amount detecting means for detecting the drive amount of the image blur correction means is further provided, and the focus control means drives the focus lens according to the drive amount of the image blur correction means detected by the drive amount detection means. The image blur correction device according to claim 1 or 2. A focus detecting means for performing focus detection based on an output signal from the imaging means is further provided, and the focus controlling means includes a detection result of the focus detecting means and the image blur correction means detected by the driving amount detecting means. The image blur correction device according to claim 3, wherein the focus lens is driven according to a driving amount of the above. Any of claims 1 to 4, wherein when the image blur correction means has a plurality of moving members, the focus control means drives the focus lens in conjunction with the drive of each of the moving members. The image blur correction device according to item 1. The image blur correction according to any one of claims 1 to 5, wherein in the case of manual focus, a mode in which the focus lens is not driven can be selected in conjunction with the operation of the image blur correction means. Device. The method according to any one of claims 1 to 6, wherein the image blur correction means is an optical member arranged in the image pickup optical system and moving in a direction orthogonal to the optical axis of the image pickup optical system. Image blur correction device. The image blur correction device according to any one of claims 1 to 6, wherein the image blur correction means is a means for moving the image pickup means in a direction orthogonal to the optical axis of the image pickup optical system. .. The focus control means according to any one of claims 1 to 8, wherein when the movement amount of the image blur correction means is less than a predetermined value, the focus lens is not driven or the drive amount is limited. The image blur correction device described. Drives an image blur correction means that moves the subject image on the screen of the image pickup means by moving in a direction orthogonal to the optical axis of the imaging optical system so as to optically correct the image blur of the subject image due to the shake of the image pickup device. Drive control process and
During the exposure period for moving images, the focus shift of the subject image caused by driving the image blur correction means to optically correct the image blur is adjusted in conjunction with the operation of the image blur correction means. Therefore, the focus control step of controlling the focus lens to be driven in the optical axis direction of the imaging optical system is provided.
In the focus control step, a control method for an image blur correction device, characterized in that the driving amount of the focus lens is limited during exposure of the imaging means. A program for causing a computer to execute each step of the control method according to claim 10. A computer-readable storage medium that stores a program for causing a computer to execute each step of the control method according to claim 10.

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