Image stabilizing device and control method thereof

A digital camera controls a blur correction lens used to correct image blur occurring due to vibration applied to the digital camera. The digital camera controls a focus lens used for focus adjustment and a zoom lens used to change an angle of view in connection with driving of the blur correction lens during exposure to an image sensor.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an image stabilizing device and a control method thereof.

Description of the Related Art

As a magnification of image pickup apparatuses such as cameras and video apparatuses increases, vibration applied to an image pickup apparatus, such as hand tremor, easily becomes conspicuous at a telescopic end and thus a high-performance image stabilizing mechanism is required. An image stabilizing mechanism is a mechanism for detecting hand tremor of a photographer and driving some of lenses constituting an imaging optical system in a direction approximately perpendicular to an optical axis to cancel out the hand tremor of the photographer. In such an image stabilizing mechanism, a blur correction lens operates away from the optical axis of the imaging optical system in order to correct captured image blur (image blur) occurring due to hand tremor. Japanese Patent Laid-Open No. 2009-145852 discloses a camera which obtains a third focusing position to which a focus lens is actually moved by weighting a first focusing position based on distance measurement and a second focusing position based on focus detection on the basis of the amount of hand tremor.

Since it is necessary to move the blur correction lens greatly in order to satisfy a demand for performance improvement in an image stabilizing mechanism, the blur correction lens moves far away from the optical axis. When the blur correction lens is driven and moves far away from the optical axis, a subject contrast at the center of an image decreases and optical performance deteriorates. An image pickup apparatus employing a contrast AF method as a focus detection method drives a focus lens to a position at which the contrast of a predetermined subject is high in order to focus the subject in a through image before starting exposure. When the subject is focused once, the image pickup apparatus maintains the position of the focus lens. However, when a camera is shaken due to hand tremor of a photographer or the like even in a state in which the subject has been focused, the hand tremor is detected in the camera and a blur correction lens operates. In addition, when the blur correction lens moves far away from the optical axis, a subject contrast at the center of an image decreases and a through image is brought into a so-called out-of-focus state.

In addition, when exposure to an imaging sensor starts, the focus lens is fixed and held without being driven during exposure. However, since hand tremor of the photographer may be detected and the blur correction lens may be driven in the camera even during exposure, an image exposed in a state in which the subject contrast has decreased may be obtained as a captured image. Accordingly, an image pickup apparatus which limits driving of a blur correction unit to a predetermined driving range in which image deterioration does not occur according to aberration before exposure if a driving amount of a blur correction lens is large may be conceived, for example. Further, an image pickup apparatus which obtains a satisfactory image without decreasing the contrast of a subject by driving a focus lens in connection with a correction operation of a blur correction lens during exposure may be conceived, for example.

However, in an image pickup apparatus which limits driving of the blur correction lens, an image stabilizing effect decreases. In addition, even in cases in which the image pickup apparatus which drives the focus lens in connection with a correction operation of the blur correction lens is applied, when the focus lens is driven on the basis of movement of the blur correction lens during exposure of a still image, an angle of view deviates during exposure and thus a captured image deteriorates.

SUMMARY OF THE INVENTION

The present invention provides an image stabilizing device capable of obtaining satisfactory captured images while providing an image stabilizing effect.

An image stabilizing device according to an embodiment of the present invention includes a first control unit configured to control a blur correction unit used to correct image blur occurring due to vibration applied to an image pickup apparatus, and a second control unit configured to control a first optical member used for focus adjustment and a second optical member used to change an angle of view in connection with driving of the blur correction unit during exposure to an imaging unit.

DESCRIPTION OF THE EMBODIMENTS

A configuration of an image pickup apparatus including an image stabilizing device according to the present embodiment will be described with reference toFIGS. 1 to 3.

A lens barrel included in the image pickup apparatus of the present embodiment has a 3-lens groups configuration. Specifically, the lens barrel includes a first-group unit composed of a first-group lens holding frame11which holds a first lens group1and a first-group ground plate12including a lens barrier member which holds the first-group lens holding frame11and protects the lenses. In addition, the lens barrel includes a diaphragm unit21which is a member for adjustment of the quantity of light during photographing, a second-group unit composed of a second-group lens holding frame31which holds a second lens group2and a second-group ground plate32including a shutter member which is not shown, and a third-group lens holding frame41which holds a third lens group3. The first-group unit, the diaphragm unit and the second-group unit are lens groups of a variable power system. The second-group unit includes an image stabilizing mechanism, and the second-group lens holding frame31moves in a direction approximately perpendicular to an optical axis during photographing to correct image blur occurring due to hand tremor during photographing. The third lens group3is a focus lens group for focusing a subject.

FIG. 1is a diagram showing a collapsed state in which lens groups are included. If a lens barrel is in a collapsed state, an image pickup apparatus is in a photographing standby state.FIG. 2is a diagram showing a photographing state in which the first-group lens holding frame11, the second-group lens holding frame31and the third-group lens holding frame41extend in an optical axis direction. The focus lens group and an imaging element5are attached to a sensor holder unit. The imaging element5is held by the sensor holder501through a sensor plate505, and an optical filter4is disposed in front of the imaging element5by being interposed between the sensor holder501and a sensor rubber material which is not shown.

FIG. 3is an example of an exploded perspective view of the lens barrel. In addition,FIG. 4shows an example of a configuration of the surroundings of a movable cam ring. As shown inFIG. 3, the lens barrel included in the image pickup apparatus of the present embodiment is composed of a fixed cam ring504which is a component constituting a zoom mechanism and a sensor holder unit fastened thereto using screws. A zoom motor601and gear trains603to606shown inFIG. 4are provided on the sensor holder501. A gear602is attached to a driving shaft in the zoom motor601, and the gear602is rotated by a driving force of the zoom motor601to transfer the driving force to a barrel member through the gear trains603to606and thus the lens barrel can be driven in the optical axis direction. The gear trains603to606are cluster gears having a large-diameter gear and a small-diameter gear having different numbers of teeth on the same shaft. The final gear606engaged with the movable cam ring503is also a cluster gear and is composed of a large-diameter gear part and a small-diameter gear part longer in the optical axis direction.

Next, a cylinder member and a zoom driving mechanism for moving each lens group in the optical axis direction will be described. As shown inFIGS. 1 and 2, the movable cam ring503is disposed on the outer circumference of each lens group. Cam grooves503a,503band503cof three types having different loci are formed on the inner circumference of the movable cam ring503, as shown inFIG. 3. Follower pins12a,21aand32aformed on the outer circumferences of the first-group ground plate12, the diaphragm unit21and the second-group ground plate32are respectively engaged with the cam grooves503a,503band503cto be able to follow them.

In addition, as shown inFIGS. 1 and 2, a rectilinear movement guide cylinder502for rotation restriction for restricting rotation when each lens group moves is provided on the inner circumference of the movable cam ring503. The rectilinear movement guide cylinder502and the movable cam ring503are so-called bayonet-connected and approximately integrally move in the optical axis direction, and the movable cam ring503is relatively rotatable with respect to the rectilinear movement guide cylinder502.

Further, long grooves502a,502band502cextending in the optical axis direction are provided on the rectilinear movement guide cylinder502, as shown inFIG. 3. The first-group ground plate12, the diaphragm unit21and the second-group ground plate32rectilinearly move in the optical axis direction when being rotationally restricted by the long grooves502a,502band502c. A cam groove504aand a rectilinear movement guide groove504bwhich is a linear groove are formed on the inner circumference of the fixed cam ring504. As shown inFIG. 3, a follower pin503dformed on the outer circumference of the movable cam ring503is engaged with the cam groove504ato be able to follow the cam groove504a, and the guide groove504bis slidably fitted to a rectilinear movement restricting part502dof the rectilinear movement guide cylinder502.

In addition, a gear part503eis formed on the outer circumference of the movable cam ring503, as shown inFIG. 3. The zoom motor601starts to drive such that the driving force is transferred from the final gear606of the gear trains603to606to the gear part503eof the movable cam ring503and thus a rotation operation is performed. Accordingly, the movable cam ring503rotates in the optical axis direction while being engaged with and following the cam groove504aformed on the inner circumference of the fixed cam ring504.

The gear part503eincluded in the movable cam ring503is engaged with a small-diameter gear which is a part of the final gear606. A large-diameter gear is positioned behind the small-diameter gear (at the imaging element) in the optical axis direction and engaged with the gear605. A long gear part of the gear606is formed to be long in the optical axis direction in accordance with an extending amount of the movable cam ring503to correspond to movement of the movable cam ring503in the optical axis direction. The rectilinear movement guide cylinder502moves in the optical axis direction integrally with the movable cam ring503. Since the rectilinear movement restricting part502dincluded in the rectilinear movement guide cylinder502is slidably fitted to the rectilinear movement guide groove504bincluded in the fixed cam ring504to restrict rotation, the rectilinear movement guide cylinder502performs only rectilinear movement. According to the aforementioned configuration, the movable cam ring503rotates and thus the first-group unit, the diaphragm unit21and the second-group unit which follow the movable cam ring503move in the optical axis direction while rectilinear movement thereof is restricted. The fixed cam ring504is connected to the sensor holder501through a screw and configured integrally therewith, as shown inFIGS. 1 to 3, and thus neither move in the optical axis direction nor a rotation direction.

FIGS. 5A and 5Bare diagrams showing an example of a configuration of an image stabilizing device included in the image pickup apparatus.

FIG. 5Ais a front view viewed from a subject side of the second-group unit.FIG. 5Bis a cross-sectional view when the image stabilizing device shown inFIG. 5Ais cut at a lens center.

A lens driving unit is provided at the side of the outer circumference of the second-group ground plate32. The lens driving unit is composed of a magnet37and a coil38. The lens driving unit moves the second-group lens holding frame31which holds the second-group lens2as a blur correction lens in a direction perpendicular to the optical axis. Accordingly, the second-group lens2corrects image blur occurring due to vibration applied to the image pickup apparatus. A shutter driving unit for driving a shutter mechanism, which is not shown, is provided at the side of the outer circumference of the second-group lens2of the second-group ground plate32, and an ND driving unit for driving an ND filter, which is not shown, is provided at the side of an image surface of the second-group ground plate32.

In addition, the second-group lens holding frame31and the second-group ground plate32are connected in the optical axis direction by two tension springs (not shown). The second-group lens holding frame31is pushed to one side with respect to the second-group ground plate32having a ball35interposed therebetween in the direction of the optical axis by a biasing force of the two tension springs. In addition, the second-group lens holding frame31which holds the second-group lens2moves in a direction perpendicular to the optical axis according to rolling of the ball35.

A Hall element holder34is disposed on the subject side of the second-group ground plate32. A shutter FPC33is laid on the Hall element holder34and pulled out to the side of the image surface along a pull-out surface of the outer circumference of the Hall element holder34in a state in which the shutter FPC33is connected to the lens driving unit, the shutter driving unit and the ND driving unit. Hall elements36for detecting the position of the second-group lens2are mounted at two points separated from each other by 90° in a circumferential direction on the shutter FPC33and connected to a lens-barrel FPC which is not shown through the shutter FPC33. The shutter FPC33is fixed to the Hall element holder34, and the Hall element holder34is engaged with the second-group ground plate32through snap-fit connection having the second-group lens2interposed therebetween.

The magnet37magnetized to have the Hall element36between the N pole and the S pole is provided in the second-group lens holding frame31and a control unit of a camera main body detects magnetic fields penetrating the magnet37as outputs of the two Hall elements36. When the second-group lens holding frame31moves in a plane perpendicular to the optical axis, magnetic fields penetrating the Hall elements36change and thus the outputs of the Hall elements36change. Accordingly, the position of the second-group lens holding frame31can be detected.

Further, the coil38is disposed at a position opposite the magnet37and the side of the image surface in the optical axis direction. The coil38is attached to the second-group ground plate32. The coil38is connected to the lens-barrel FPC which is not shown through the shutter FPC33and provided with power from a power supply unit of the camera main body. In addition, the coil38is biased to generate an electromagnetic force, and thus the second-group lens holding frame31can be driven.

FIGS. 6A and 6Bare diagrams showing an example of a configuration of a focus driving mechanism attached to the sensor holder unit.

The sensor holder501supports the third-group lens holding frame41such that the third-group lens holding frame41can rectilinearly move in the optical axis direction. That is, a main guide shaft42parallel with a photographing optical axis is press-fitted into a hole part of the sensor holder501to be fixed to the sensor holder501, as shown inFIGS. 3, 6A and 6B. Further, a sub-guide shaft43for restricting rotation is press-fitted into the hole part of the sensor holder501to be fixed like the main guide shaft42. In addition, a focus driving motor44is fastened and fixed to the sensor holder501by means of screws, as shown inFIGS. 6A and 6B. A sleeve41ais formed at the third-group lens holding frame41. A sleeve hole having both edges engaged with the main guide shaft42is formed in the sleeve41aand a sleeve opening is formed at the center of the sleeve41a. Further, a U-shaped groove41bengaged with the sub-guide shaft43is formed in the third-group lens holding frame41. In addition, a support hole41cfor supporting a rack45is provided in proximity to the sleeve41ain the third-group lens holding frame41.

The rack45includes engagement teeth45aengaged with a lead screw44aformed integrally with a motor output shaft, and biasing teeth45bfacing the engagement teeth45a. In addition, a support shaft engaged with a support hole of the third-group lens holding frame41is formed in the rack45. The biasing teeth45bare pressed in a direction in which the biasing teeth45bengage with the lead screw44aby means of an arm part of a torsion coil spring46, and the arm part of the torsion coil spring46is hooked on the rear side of the rack45. Accordingly, the biasing teeth45band the engagement teeth45apinch the lead screw44atherebetween and are engaged with the lead screw44aall the time.

In addition, the torsion coil spring46also biases the rack45in a direction facing the end face of the third-group lens holding frame41in the optical axis direction to prevent backlash between the rack45and the third-group lens holding frame41and stabilize them in the optical axis direction such that driving with high accuracy can be achieved. In such a configuration, when the lead screw44aof the focus driving motor44rotates, the third-group lens holding frame41moves forward and backward in the optical axis direction according to a screwing relation between the rack45and the lead screw44a.

FIG. 7is a functional block diagram of the image pickup apparatus of the present embodiment.

FIG. 7shows a configuration of a digital camera100as an example of the image pickup apparatus. The digital camera100includes a lens barrel101and a zoom control unit127. The lens barrel101holds a lens group therein and drives lenses. A blur correction lens103serves as a blur correction unit used to correct image blur occurring due to vibration applied to the image pickup apparatus. The blur correction lens103is an optical member which moves in a direction different from an optical axis of an imaging optical system and corrects image blur by off-centering the optical axis. A focus lens104is a first optical member used to adjust a focus point (focus adjustment). A zoom lens102is a second optical member used to optically change an angle of view by controlling the focal distance. A diaphragm and shutter105is used for exposure control for adjusting the quantity of light.

Light which has passed through the lens barrel101is received by an imaging element106using a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS) or the like and converted from an optical signal into an electrical signal. The electrical signal is input to an image processing circuit107, subjected to a pixel interpolation process, a color conversion process and the like and then sent to an internal memory108as image data. A display unit109displays imaging information and the like along with a captured image. A compression/decompression processor110compresses or decompresses data stored in the internal memory108according to an image format. A storage unit111stores various types of data such as parameters. A vibration detection unit113detects vibration (shaking) applied to the digital camera100.

A system control unit119controls the digital camera100overall. The function of the image stabilizing device of the present embodiment is realized by the system control unit119. The system control unit119is configured as an operation device such as a central processing unit (CPU) to execute various control programs stored in the internal memory108, for example, programs for performing AE control, AF control, image stabilizing control, zoom control and the like, according to a user operation.

The system control unit119includes an exposure control unit120and the zoom control unit127. A luminance signal computing unit121computes an electrical signal output from the imaging element106as a luminance of a subject. The exposure control unit120calculates exposure control values (a diaphragm value and a shutter speed) on the basis of luminance information obtained by the luminance signal computing unit121and sends a calculation result to a diaphragm shutter driving unit114. The diaphragm shutter driving unit114drives the diaphragm and shutter105on the basis of the calculation result sent from the exposure control unit120. In this manner, automatic exposure (AE) control is performed.

An estimation value calculation unit122extracts a specific frequency component from the luminance signal computed by the luminance signal computing unit121and then calculates an AF estimation value (contrast estimation value) on the basis of a focus lens correction amount output from a position correction unit126. The focus lens correction amount is a correction amount for the position of the focus lens104. A scanning control unit124performs driving commands in a predetermined range for the focus control unit123. In addition, the scanning control unit124calculates a form of contrast with reference to an AF estimation value which is a calculation result of the estimation value calculation unit122at a predetermined position of the focus lens104on the basis of the output of the position correction unit126. A focus point at which contrast is highest is regarded as a point at which a light flux is focused on the surface of the imaging element106. The focus control unit123controls a focus lens driving unit115such that the focus lens104is driven on the basis of the output of the scanning control unit124. Accordingly, automatic focus (AF) control is performed.

A correction lens current position detection unit117detects a current position of the blur correction lens103. An image stabilization control unit125outputs a control signal for correcting image blur on the basis of the current position of the correction lens103and a vibration detection signal output from the vibration detection unit113. A correction lens driving unit116drives the blur correction lens103on the basis of the control signal output from the image stabilization control unit125.

A position correction unit126calculates a focus lens correction amount on the basis of a movement amount (driving amount) of the blur correction lens103which corresponds to the control signal output from the image stabilization control unit125. In addition, the position correction unit126calculates a correction amount for the position of the zoom lens102(zoom lens correction amount) on the basis of the driving amount of the blur correction lens103. In this example, it is assumed that information (first information) representing relationships between driving amounts of the blur correction lens and focus lens correction amounts and information (second information) representing relationships between driving amounts of the blur correction lens and zoom lens correction amounts are stored in advance in the internal memory108. The position correction unit126calculates a focus lens correction amount on the basis of the first information stored in the internal memory108. In addition, the position correction unit126calculates a zoom lens correction amount on the basis of the second information stored in the internal memory108. A zoom control unit127outputs a control signal used to drive the zoom lens102. The zoom control unit127outputs a control signal on the basis of a zoom operation instruction from an operation unit112. Further, if the position correction unit126calculates a zoom lens correction amount, the zoom control unit127outputs a control signal in response to the zoom lens correction amount. A zoom lens driving unit118drives the zoom lens102on the basis of the control signal output from the zoom control unit127.

The operation unit112is a user interface which performs various menu operations and a mode switching operation. For example, the operation unit112performs switching between a still image and a moving image and switching between manual focus and automatic focus according to user operations. The operation unit112includes a release button for turning on a first switch SW1and a second switch SW2in turn in response to a pressing amount. In the example shown inFIG. 7, SW1is on when the release button is pressed about half and SW2is on when the release button is completely pressed. When SW1is on, the exposure control unit120calculates exposure control values (a diaphragm value and a shutter speed). When SW2is on, the exposure control unit120controls the diaphragm shutter driving unit114on the basis of the diaphragm value and the shutter speed. Image data acquired as a result of imaging performed by the imaging element106is stored in the storage unit111. When a so-called live image acquired in a state in which the release button is not pressed is displayed, the exposure control unit120is provided for exposure during still image photographing to preliminarily determine a diaphragm value and a shutter speed at predetermined intervals on the basis of luminance information about an image signal and a program diagram.

FIGS. 8A to 8Dare diagrams describing subject out-of-focus which is a phenomenon occurring when the blur correction lens is separated from the optical axis of the imaging optical system.

FIGS. 8A and 8Bshow a relationship between the contrast of a subject and the position of the focus lens104. The X axis represents the position of the focus lens104. The Y axis represents an estimation value of the contrast of the subject (contrast estimation value). As shown inFIGS. 8A and 8B, the contrast estimation value changes according to the position of the focus lens104and thus a mountain form due to a height difference in the contrast can be formed. The peak of the mountain is a position at which the contrast estimation value is maximized, and focusing is achieved when the focus lens104is disposed at this position.

FIG. 8Cshows a state in which the blur correction lens103and other lenses included in the lens barrel101are disposed on the same optical axis. If the blur correction lens103is placed at the position shown inFIG. 8C, the contrast estimation value corresponding to a position X1of the focus lens104is maximized, as shown inFIG. 8A.FIG. 8Dshows a state in which the blur correction lens103is driven to be separated from the optical axis and disposed. If the blur correction lens103is placed at the position shown inFIG. 8D, the mountain form shown inFIG. 8Ais deviated to the right and thus the contrast estimation value corresponding to a position X2of the focus lens104is maximized, as shown inFIG. 8B.

A state in which the focus lens104operates to move to the position X1and stops at the position X1to focus the subject when the blur correction lens103is positioned on the optical axis is assumed. Thereafter, when the blur correction lens103is driven, the contrast estimation value decreases from Y1to Y2at the position X1of the focus lens104, as shown inFIG. 8B. Accordingly, a photographing operation is performed in a state in which the contrast estimation value is low. Further, since hand tremor of a photographer constantly changes rather than being uniform, the movement of the blur correction lens103is not uniform and the contrast of a subject also constantly changes. Accordingly, it is necessary to drive the focus lens104(perform focus correction control) in response to movement of the blur correction lens103.

FIGS. 9A and 9Bare diagrams describing relationships between a movement amount (driving amount) of the blur correction lens and a focus lens correction amount and a zoom lens correction amount. Operations of the blur correction lens, the focus lens and the zoom lens before and after photographing will be described with reference to the graphs shown inFIGS. 9A and 9B.

FIG. 9Ashows a relationship between a driving amount of the blur correction lens103and a focus lens correction amount. The Y axis represents the position of the blur correction lens103from the optical axis. The X axis represents a correction amount of the position of the focus lens104(focus lens correction amount) to be corrected when the blur correction lens103has been driven. Compx (x=0 to 5) represents a focus lens correction amount. The focus lens correction amount increases as x increases. That is, Comp0 is zero and Comp5 is a maximum.

If the position of the blur correction lens103is 0 degrees, that is, the center of the optical axis, the driving amount of the blur correction lens103is represented as Mov0 in the graph ofFIG. 9A. If the driving amount of the blur correction lens103is Mov0, the focus lens correction amount is Comp0. As specific numerical values, Mov0 is 0 degrees and the focus lens correction amount is Comp0. In addition, if the position of the blur correction lens103is farthest from the center of the optical axis, the driving amount of the blur correction lens103is represented as Mov5 in the graph ofFIG. 9A. If the driving amount of the blur correction lens103is Mov5, the focus lens correction amount is Comp5. In the present embodiment, the first information representing relationships between driving amounts of the blur correction lens103and focus lens correction amounts is stored in the internal memory108, and the position correction unit126calculates a focus lens correction amount with reference to the first information in the internal memory108. Accordingly, when a predetermined subject is photographed, the focus lens104moves by an amount corresponding to a hand tremor amount of a photographer and thus deterioration of the contrast of the subject on a live view is prevented.

FIG. 9Bis a diagram describing a relationship between a driving amount of the blur correction lens103and a zoom lens correction amount. The Y axis represents the position of the blur correction lens103from the optical axis. The X axis represents a correction amount of the zoom lens102(zoom lens correction amount) to be corrected when the blur correction lens103has been driven. Compx (x=0 to 5) represents a zoom lens correction amount. The zoom lens correction amount increases as x increases. That is, Comp0 is zero and Comp5 is a maximum.

If the position of the blur correction lens103is 0 degrees, that is, the center of the optical axis, the driving amount of the blur correction lens103is represented as Mov0 in the graph ofFIG. 9B. If the driving amount of the blur correction lens103is Mov0, the zoom lens correction amount is Comp0. As specific numerical values, Mov0 is 0 degrees and the zoom lens correction amount is Comp0. In addition, if the position of the blur correction lens103is farthest from the center of the optical axis, the driving amount of the blur correction lens103is represented as Mov5 in the graph ofFIG. 9B. If the driving amount of the blur correction lens103is Mov5, the zoom lens correction amount is Comp5. In the present embodiment, the second information representing the relationship between driving amounts of the blur correction lens103and zoom lens correction amounts is stored in the internal memory108, and the position correction unit126calculates a zoom lens correction amount with reference to the second information in the internal memory108. Accordingly, when a predetermined subject is photographed, the zoom lens102moves by an amount corresponding to a hand tremor amount of a photographer and thus deterioration of the contrast of the subject on a live view can be prevented.

Numerical values including Mov5 and Comp5 inFIGS. 9A and 9Bchange according to characteristics of the imaging optical system. Further, although the relationships between the driving amount of the blur correction lens and the focus lens correction amount and the zoom lens correction amount are linear inFIGS. 9A and 9B, these relationships may change to curved lines according to characteristics of the imaging optical system.

The image pickup apparatus of the present embodiment drives the focus lens104and the zoom lens102in connection with driving of the blur correction lens103on the basis of the first information and the second information stored in the internal memory108. Accordingly, it is possible to correct a deviation in an angle of view due to correction of the position of the focus lens104in response to driving of the blur correction lens103by driving the zoom lens102.

FIGS. 10 and 11are flowcharts describing an operation process of the image pickup apparatus of the present embodiment.

The process pertaining to the flowcharts to be described with reference to FIGS.10and11is performed under the control of the system control unit119. In S401ofFIG. 10, power is on. In S402, the system control unit119calculates an image stabilization amount in response to vibration applied to the digital camera100. Subsequently, the system control unit119drives the blur correction lens103on the basis of the calculated image stabilization amount in S403. Accordingly, image stabilization control is started.

Next, the system control unit119drives the focus lens104in response to a driving amount of the blur correction lens103in S404. Accordingly, focus correction control is started. Subsequently, the system control unit119determines whether SW2is pressed in S405. If SW2is not pressed, the process returns to S402in a live view image state and operations of S403and S404are repeatedly performed. If SW2is pressed, the system control unit119starts a still image photographing operation in S406. Accordingly, exposure to the imaging element106is started to enter a photographing state.

In S407, the system control unit119calculates an image stabilization amount in response to vibration applied to the digital camera100. Subsequently, the system control unit119performs image stabilization control on the basis of the calculated image stabilization amount in S408. That is, the system control unit119serves as a first control unit which drives and controls the blur correction lens103during exposure. Subsequently, the process enters a loop operation in which the focus lens104and the zoom lens102are driven in connection with the blur correction lens103according to the system control unit119in S409to S414inFIG. 11.

In S409, the system control unit119determines whether the driving amount of the blur correction lens103is within a range of predetermined amounts (threshold values). If the driving amount of the blur correction lens103is equal to or less than a predetermined amount A (equal or less than a first threshold value), the system control unit119does not perform an operation of correcting the positions of the focus lens104and the zoom lens102, and the process proceeds to S414. That is, if the driving amount of the blur correction lens103is equal to or less than the predetermined amount A, driving of the focus lens104and the zoom lens102in connection with driving of the blur correction lens103is not performed. In S414, the system control unit119determines whether an exposure period has ended. If the exposure period has not ended, the process returns to S409. If the exposure period has ended, the process proceeds to S415. Then, the system control unit119ends exposure in S415.

If the driving amount of the blur correction lens103is greater than the predetermined amount A and equal to or less than a predetermined amount B (equal or less than a second threshold value) in the determination process of S409, the process proceeds to S410. The predetermined amount B (second threshold value) is set to a value larger than the predetermined amount A (first threshold value). In S410, the system control unit119performs an operation of correcting the position of the focus lens104in response to the driving amount of the blur correction lens103.

Next, the system control unit119determines whether an exposure time exceeds a predetermined time in S411. If the exposure time is equal to or less than the predetermined time, the system control unit119continues to drive the focus lens104without driving the zoom lens102in connection there with. Then, the process proceeds to step414. If the exposure time exceeds the predetermined time, the process proceeds to S413. Then, the system control unit119serves as a second control unit to drive the focus lens104and the zoom lens102in connection with driving of the blur correction lens103in S413. Thereafter, the process proceeds to step414.

In addition, if the system control unit119determines that the driving amount of the blur correction lens103is greater than the predetermined amount B in the determination process of S409, the process proceeds to S413. Then, the system control unit119drives the focus lens104and the zoom lens102in connection with driving of the blur correction lens103in S413.

The image pickup apparatus of the present embodiment cooperatively drives the focus lens104and the zoom lens102in connection with driving of the blur correction lens103according to conditions pertaining to the driving amount of the blur correction lens103. Accordingly, it is possible to prevent an angle of view from deviation by driving the focus lens104in connection with driving of the blur correction lens103while mitigating deterioration of subject contrast due to large separation of the blur correction lens103from the optical axis. Consequently, a satisfactory image can be acquired.

The application range of the present invention is not limited to the above description with reference toFIGS. 10 and 11. According to the flowcharts ofFIGS. 10 and 11, only the focus lens104is driven in connection with driving of the blur correction lens103and driving of the zoom lens102is not performed before exposure (S404inFIG. 10). However, the system control unit119may drive the zoom lens102in connection with the focus lens104before exposure. In addition, if an operation mode in which focus adjustment is manually performed is set, the system control unit119may select an operation mode in which the focus lens104and the zoom lens102are not driven in connection with driving of the blur correction lens103.

Although an example of application to an image pickup apparatus with respect to the present invention has been described, the present invention is not limited to the above-described embodiment and also includes various forms without departing from the scope and spirit of the present invention. For example, although the image pickup apparatus uses a lens barrel having a 3-group configuration in the above-described embodiment, the lens barrel included in the image pickup apparatus may not have the 3-group configuration.

Furthermore, the image pickup apparatus includes a plurality of blur correction lenses and the system control unit119drives the focus lens104and the zoom lens102in response to driving amounts of the blur correction lenses103. In addition, an imaging element may be applied as a blur correction unit for correcting image blur instead of the blur correction lens and driven within a surface perpendicular to the operation axis.

This application claims the benefit of Japanese Patent Application No. 2018-002299, filed Jan. 11 2018, which is hereby incorporated by reference wherein in its entirety.