In an apparatus such as an image-shake preventing apparatus and a control method therefor, an image-shake preventing unit is caused to gradually come into contact with a movable-range end when an image-shake preventing operation is ended.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to an apparatus such as an image-shake
 preventing apparatus for preventing the shake of an image, and to a
 control method therefor.
 2. Description of Related Art
 It is known that, in an image pickup apparatus such as a small-sized video
 camera, a picked-up object image shakes due to the vibration of the image
 pickup apparatus, so that a video image intolerable to view might be
 outputted or recorded.
 In particular, in such a kind of image pickup apparatus, it has become
 general these days that a zoom lens capable of continuously varying the
 focal length without changing the image point position is mounted in the
 image pickup apparatus, and, in recent years, an image pickup apparatus
 having a high zoom magnification ratio of ten or more times has widely
 come into the market. However, such an image pickup apparatus has a
 drawback that, when an object image is picked up with the setting of the
 telephoto side, which is set for the larger zoom magnification, a
 conspicuous shaking of the object image would occur.
 Therefore, as measures to solve the above drawback, an image pickup
 apparatus having mounted therein an image pickup optical system having
 image-shake correcting means has been developed so far and has already
 been put on the market.
 FIG. 18 is a conceptual diagram schematically showing the above-mentioned
 image pickup optical system, which is denoted by reference numeral 200. In
 the image pickup optical system 200, there are disposed, in order, a fixed
 lens 201 securely fixed to a lens barrel (not shown), a variator lens 202
 arranged to move in the horizontal direction on an optical axis "c" as
 indicated by an arrow "a", a shift lens 203 arranged to move
 two-dimensionally within a plane perpendicular to the optical axis "c" (in
 the direction indicated by an arrow "b", a focusing lens 204 having the
 focus adjusting function and the function of correcting the movement of a
 focal plane resulting from the movement of the variator lens 202, and an
 image sensor 205 on which to form an object image. Further, in the
 respective predetermined positions adjacent to the shift lens 203, there
 are disposed an actuator 206 arranged to drive the shift lens 203 and a
 position detecting sensor 207 arranged to detect the position of the shift
 lens 203.
 In the image pickup apparatus 200, even if, as shown in FIG. 19(a), the
 optical axis "c" deviates from a central axis "c'" of the image pickup
 optical system 200 due to the vibration thereof as much as a deviation
 angle e, it is possible to make the optical axis "c" and the central axis
 "c'" of the image pickup optical system 200 geometrically coincident with
 each other on the downstream side of the shift lens 203, by driving the
 actuator 206 to move the shift lens 203 as indicated by an imaginary line
 in FIG. 19(b). Accordingly, the above-mentioned deviation angle .theta. is
 corrected by an optical processing, so that the object image is formed on
 the image sensor 205 as a light flux having no shaking.
 FIG. 20 is a block diagram showing the arrangement of a conventional image
 pickup apparatus which corrects an image shake by means of the image
 pickup optical system 200.
 In the image pickup optical system shown in FIG. 20, when a power supply
 switch 208 is turned on, a mode microcomputer 209 notifies a main
 microcomputer 210 of the turning-on of the power supply switch 208. Then,
 having determined that the power supply has been turned on, the main
 microcomputer 210 starts its control operation.
 Subsequently, a vibration signal forming circuit 211, which has detected
 the vibration of the body of the image pickup apparatus, forms a vibration
 signal and supplies the vibration signal to a vibration correcting circuit
 212. In the vibration correcting circuit 212, the analog vibration signal
 is converted into a digital vibration signal by an A/D converter 213, and,
 then, a predetermined low-frequency component is removed from the digital
 vibration signal by a high-pass filter (HPF) 214. After that, the phase
 and gain of an output signal of the HPF 214 are corrected by a phase/gain
 correcting circuit and an output signal of the phase/gain correcting
 circuit 215 is integrated by an integration circuit 216 to calculate and
 output a correction target value.
 The correction target value outputted from the vibration correcting circuit
 212 is converted into an analog value by a D/A converter 217 and is then
 supplied to an adder 218. At the adder 218, the analog correction target
 value is added to a feedback signal supplied from the position detecting
 sensor 207 through an amplifier 219. Then, an output signal of the adder
 218 is supplied to a driving circuit 220. The driving circuit 220 issues a
 driving signal to the actuator 206 to drive the shift lens 203.
 When the shift lens 203 is driven by the actuator 206, as described above,
 the deviation angle e is optically corrected, so that the object image is
 formed on the image sensor 205 as a light flux having no shaking.
 Further, an electric signal obtained through the photo-electric conversion
 by the image sensor 205 is supplied to a video signal processing circuit
 222 via a camera signal processing circuit 221. Then, a video signal
 produced by the video signal processing circuit 222 is outputted to an
 output terminal 223 so as to be converted into a visible video image on
 the display screen, and, at the same time, is recorded, as video
 information in the form of an RF signal, on a recording medium such as a
 magnetic tape by a recorder 224.
 Incidentally in the above-mentioned image pickup apparatus, the actuator
 206 for driving the shift lens 203 is composed of a voice coil motor.
 More specifically, the voice coil motor is disposed in a predetermined
 position adjacent to the shift lens 203. By causing current to flow to the
 voice coil motor to generate an electromagnetic force, the shift lens 203
 is made to float, and by varying the electromagnetic force according to an
 output of the adder 218, the shift lens 203 is made to two-dimensionally
 move within a plane perpendicular to the optical axis "c" in the vertical
 direction (in the pitching direction) and in the horizontal direction (in
 the yawing direction).
 However, since, in the conventional image pickup apparatus, as described
 above, the actuator 206 is composed of a voice coil motor, the shift lens
 203 is held in a floating state by the voice coil motor when the voice
 coil motor is a conductive state with the power supply switch 208 turned
 on, but, when the power supply is turned off, the holding force for the
 shift lens 203 by the voice coil motor is canceled, so that the shift lens
 203 drops due to its own weight. As a result, a lens holding frame which
 holds the shift lens 203 collides with an inner wall of the lens barrel to
 generate a collision sound, which is offensive to the ear.
 Further, since the optical axis "c" decenters due to the movement of the
 shift lens 203, for example, if the power supply is turned off during the
 process of an image pickup operation of the image pickup apparatus, there
 is a possibility that a video image having an unnatural motion is
 outputted or recorded on the recording medium.
 BRIEF SUMMARY OF THE INVENTION
 In accordance with one aspect of the invention, there are provided an
 apparatus such as an image-shake preventing apparatus and a control method
 therefor, in which an image-shake preventing unit is caused to gradually
 come into contact with a movable-range end when an image-shake preventing
 operation is ended, so that it is possible to prevent the image-shake
 preventing unit from colliding with the movable-range end to generate a
 collision sound when the image-shake preventing operation is ended.
 In accordance with another aspect of the invention, there are provided an
 apparatus such as an image-shake preventing apparatus and a control method
 therefor, in which an image-shake preventing unit is caused to come into
 contact with a movable-range end when an image-shake preventing operation
 is ended, and an operation for causing the image-shake preventing unit to
 come into contact with the movable-range end is started after completion
 of counting of a predetermined period of time after an instruction for
 ending the image-shake preventing operation is issued, so that it is
 possible to prevent an unnatural video image from being outputted or being
 recorded due to the contact of the image-shake preventing unit with the
 movable-range end at the time of the end of the image-shake preventing
 operation.
 In accordance with another aspect of the invention, there are provided an
 apparatus such as an image-shake preventing apparatus and a control method
 therefor, in which an image-shake preventing unit is caused to come into
 contact with a movable-range end when an image-shake preventing operation
 is ended, and an operation for causing the image-shake preventing unit to
 come into contact with the movable-range end is inhibited from starting,
 until an image pickup apparatus ends an image pickup operation, even if an
 instruction for ending the image-shake preventing operation is issued, so
 that it is possible to prevent an unnatural video image from being
 outputted due to the contact of the image-shake preventing unit with the
 movable-range end at the time of the end of the image-shake preventing
 operation.
 In accordance with another aspect of the invention, there are provided an
 apparatus such as an image-shake preventing apparatus and a control method
 therefor, in which an image-shake preventing unit is caused to come into
 contact with a movable-range end when an image-shake preventing operation
 is ended, and an operation for causing the image-shake preventing unit to
 come into contact with the movable-range end is inhibited from starting,
 until an image recording apparatus ends an image recording operation, even
 if an instruction for ending the image-shake preventing operation is
 issued, so that it is possible to prevent an unnatural video image from
 being recorded due to the contact of the image-shake preventing unit with
 the movable-range end at the time of the end of the image-shake preventing
 operation.
 The above and other aspects and features of the invention will become
 apparent from the following detailed description of preferred embodiments
 thereof taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION
 Hereinafter, preferred embodiments of the invention will be described in
 detail with reference to the drawings.
 FIG. 1 is a schematic diagram showing the arrangement of an image pickup
 optical system mounted on an image pickup apparatus according to each
 embodiment of the invention. The image pickup optical system, which is
 denoted by reference numeral 1, is provided with a fixed lens 3 securely
 fixed to a lens barrel 2 and arranged to have a light signal from an
 object incident thereon, a variator lens 5 arranged to move in the
 horizontal direction along an optical axis 4 so as to vary the
 magnification of an object image, an iris 6 arranged to adjust the amount
 of incident light, a shift lens 7 arranged to two-dimensionally move in
 the vertical direction (hereinafter referred to also as the pitching
 direction) and in the horizontal direction (hereinafter referred to also
 as the yawing direction) within a plane vertical to the optical axis 4, a
 focusing lens 8 having the focus adjusting function and the function of
 correcting the deviation of focus resulting from the movement of the
 variator lens 5, and an image sensor 9, such as a CCD, arranged to have
 the object image formed thereon and to convert the light signal into an
 electrical signal.
 The image pickup optical system 1 is further provided with voice coil
 motors 10p and 10y serving as actuators to drive the shift lens 7 in the
 pitching direction and in the yawing direction, and Hall elements 11p and
 11y serving as position detecting sensors to detect the positions in the
 pitching direction and the yawing direction of the shift lens 7.
 More particularly, an image stabilizing unit 12, which includes the shift
 lens 7, the voice coil motors 10p and 10y and the Hall elements 11p and
 11y, is disposed between the iris 6 and the focusing lens 8 so as to
 prevent the image shake caused by the vibration or the like of the image
 pickup apparatus.
 FIG. 2 is an exploded perspective view of the image stabilizing unit 12.
 In FIG. 2, reference numeral 13 denotes a lens holding frame. The shift
 lens 7 is held by a cylindrical part 14 of the lens holding frame 13.
 Further, on the outer circumferential portion of the lens holding frame 13,
 there are formed three holes 15a, 15b and 15c at intervals of 120.degree.
 around the optical axis 4. Guide pins 16a, 16b and 16c of approximately
 columnar shape are press-fitted or bonded into the holes 15a, 15b and 15c,
 respectively, whereby the guide pins 16a, 16b and 16c are held integrally
 with the lens holding frame 13.
 Reference numeral 18 denotes a guide plate, which is formed into an
 approximately rectangular shape. Near the corners of the guide plate 18,
 there are formed holes 19a, 19b, 20a and 20b of the slot shape which is
 long in the radial direction.
 Further, reference numeral 23 denotes an intermediate tube. The
 intermediate tube 23 is provided with a guide part (not shown), which
 protrudes from the surface of the intermediate tube 23 facing the lens
 holding frame 13 and has holes formed into the slot shape which is long in
 the circumferential direction.
 The guide pins 16a, 16b and 16c engage with the holes formed on the guide
 part of the intermediate tube 23, and pins 22a and 22b which are
 protrusively mounted on the surface of the lens holding frame 13 facing
 the guide plate 18 engage with the holes 19a and 19b of the guide plate
 18. Further, pins (not shown) which are protrusively mounted on the
 surface of the intermediate tube 23 facing the guide plate 18 engage with
 the holes 20a and 20b of the guide plate 18. Thus, by such an arrangement,
 the lens holding frame 13 is positioned in the rotating direction (rolling
 direction) around the optical axis 4 with respect to the intermediate tube
 23, and is, therefore, made to be guided only in the pitching direction
 and the yawing direction.
 Further, two magnets 25p and 25y having back yokes 24p and 24y securely
 fixed thereto are accommodated into recessed portions 26p and 26y of the
 intermediate tube 23 in such a way as to be located orthogonal to each
 other and are securely fixed to the intermediate tube 23. Further, an
 upper yoke 27 is fixed to the intermediate tube 23 at a predetermined
 interval with respect to the magnets 25p and 25y. Thus, the back yokes 24p
 and 24y, the magnets 25p and 25y and the upper yoke 27 constitute a
 magnetic circuit. Then, coils 28p and 28y are fixed to the lens holding
 frame 13 at a predetermined interval with respect to the magnets 25p and
 25y while confronting the magnets 25p and 25y. The back yokes 24p and 24y,
 the magnets 25p and 25y, the upper yoke 27 and the coils 28p and 28y
 constitute the voice coil motors 10p and 10y (see FIG. 1). When a current
 is made to flow to the coils 28p and 28y, which are located orthogonal to
 each other, to generate an electromagnetic force, there is generated a
 floating force for two-dimensionally moving the shift lens 7 in the
 pitching direction and in the yawing direction within a plane
 perpendicular to the optical axis 4. Thus, a composite force of
 electromagnetic forces generated by the current flowing to the coils 28p
 and 28y acts on the lens holding frame 13, so that the shift lens 7 is
 driven in the pitching direction and in the yawing direction.
 Further, reference numeral 29 denotes a sensor holder, on which the Hall
 elements 11p and 11y are mounted. The sensor holder 29 is fixed to the
 intermediate tube 23. In addition, magnets 17p and 17y having yokes 17ap
 and 17ay stuck thereto are fixed to the lens holding frame 13. The magnets
 17p and 17y are magnetized to have magnetic inclination in the driving
 direction of the lens holding frame 13. The Hall elements 11p and 11y are
 disposed at a predetermined interval with respect to the magnets 17p and
 17y and are arranged to detect the position of the shift lens 7 (the lens
 holding frame 13) on the basis of a change in magnetic flux resulting from
 the movement of the magnets 17p and 17y.
 FIG. 3 is a block diagram showing the arrangement of a control system of an
 image pickup apparatus according to a first embodiment of the invention.
 Referring to FIG. 3, the image pickup apparatus is provided with the
 above-mentioned image pickup optical system 1, a vibration signal forming
 circuit 30 arranged to detect the vibration of the body of the image
 pickup apparatus to form vibration signals, a driving amount control part
 31 arranged to control the amounts of driving of the shift lens 7 on the
 basis of outputs of the vibration signal forming circuit 30, etc., a mode
 microcomputer 32 arranged to watch the operation state of the image pickup
 apparatus body, a power supply switch 33 arranged to be operated to start
 the power supply of the image pickup apparatus body, D/A converters 34p
 and 34y arranged to convert the digital signals outputted from the driving
 amount control part 31 into analog signals, amplifiers 35p and 35y
 arranged to amplify the output signals of the Hall elements 11p and 11y,
 adders 36p and 36y arranged to add the feedback signals from the
 amplifiers 35p and 35y to the output signals of the D/A converters 34p and
 34y, and driving circuits 37p and 37y arranged to drive the voice coil
 motors 10p and 10y on the basis of the output signals of the adders 36p
 and 36y.
 The vibration signal forming circuit 30, concretely describing, includes
 angular velocity sensors 38p and 38y disposed at appropriate portions of
 the image pickup optical system 1 to detect the vibration angles of the
 image pickup apparatus body, high-pass filters (HPFs) 39p and 39y arranged
 to remove DC components from the detection signals outputted from the
 angular velocity sensors 38p and 38y, amplifiers 40p and 40y arranged to
 amplify the output signals of the HPFs 39p and 39y, and low-pass filters
 (LPFs) 41p and 41y arranged to remove predetermined high-frequency
 components from the output signals of the amplifiers 40p and 40y to form
 the vibration signals.
 Further, the driving amount control part 31 includes, as shown in FIG. 4,
 A/D converters 42p and 42y arranged to convert the analog vibration
 signals outputted from the vibration signal forming circuit 30 into
 digital vibration signals, HPFs 43p and 43y arranged to remove
 predetermined low-frequency components from the output signals of the A/D
 converters 42p and 42y, phase/gain correcting circuits 44p and 44y
 arranged to correct the phase and/or gain of the output signals of the
 HPFs 43p and 43y, integration circuits 45p and 43y arranged to integrate
 the output signals of the phase/gain correcting circuits 44p and 44y to
 form correction target values for correcting the image shake, a
 predetermined-value output circuit 46 arranged to output a lens-movement
 target value (a predetermined value A) which is desired irrespective of
 the vibration signals from the vibration signal forming circuit 30, and a
 change-over switch 47 arranged to change over the output signals of the
 integration circuits 45p and 45y and the output signal of the
 predetermined-value output circuit 46. The contact "a" of the change-over
 switch 47 is connected to the integration circuits 45p and 45y, the
 contact "b" of the change-over switch 47 is connected to the
 predetermined-value output circuit 46, and the contact "c" of the
 change-over switch 47 is connected to the mode microcomputer 32. Then, the
 contact "c" of the change-over switch 47 is connected to the contact "a"
 or the contact "b" depending on the signal from the mode microcomputer 32,
 which watches the state of the power supply switch 33, so that the
 correction target values from the integration circuits 45p and 45y or the
 predetermined value A from the predetermined-value output circuit 46 is
 outputted from the change-over switch 47.
 In the image pickup apparatus having the above construction, when the power
 supply switch 33 is turned on, the mode microcomputer 32 detects the
 turning-on of the power supply switch 33 and starts its control operation.
 Then, when the angular velocity sensors 38p and 38y detect the vibration of
 the image pickup apparatus body, the HPFs 39p and 39y, the amplifiers 40p
 and 40y and the LPFs 41p and 41y perform predetermined processing to form
 vibration signals. The formed vibration signals are supplied to the
 driving amount control part 31. In the driving amount control part 31,
 correction target values are calculated via the A/D converters 42p and
 42y, the HPFs 43p and 43y, the phase/gain correcting circuits 44p and 44y
 and the integration circuits 45p and 45y. The calculated correction target
 values are outputted to the D/A converters 34p and 34y via the change-over
 switch 47.
 Subsequently, the correction target values, which have been converted into
 analog signals by the D/A converters 34p and 34y, are supplied to the
 adders 36p and 36y, where the analog correction target values are added to
 the feedback signals supplied from the Hall elements 11p and 11y via the
 amplifiers 35p and 35y. Then, the output signals of the adders 36p and 36y
 are supplied to the driving circuits 37p and 37y. The driving circuits 37p
 and 37y issue driving signals to the voice coil motors 10p and 10y to
 two-dimensionally drive the shift lens 7 in the vertical direction and in
 the horizontal direction within a plane perpendicular to the optical axis
 4 during the image pickup operation on an object image.
 On the other hand, when the power supply switch 33 is changed over from the
 on-state to the off-state, a notice of the change-over of the state of the
 power supply switch 33 is given to the mode microcomputer 32, and the
 connection of the change-over switch 47 of the driving amount control part
 31 is changed over from the side of the integration circuits 45p and 45y
 to the side of the predetermined-value output circuit 46. Accordingly, the
 predetermined value A, instead of the correction target values, is
 outputted from the driving amount control part 31, so that the shift lens
 7 is made to be driven on the basis of the predetermined value A.
 FIG. 5 is a flow chart showing the lens-position control method according
 to the first embodiment of the invention. A program for the lens-position
 control method is executed by the driving amount control part 31.
 Referring to FIG. 5, in step S1, the whole system is initialized. By this
 initializing process, first and second flags F1 and F2, which will be
 described later, are cleared to "0".
 In the next step S2, correction target values used during the image pickup
 operation are calculated by subjecting the vibration signals formed by the
 vibration signal forming circuit 30 to the predetermined filtering process
 at the HPFs 43p and 43y, to the phase and gain correction at the
 phase/gain correcting circuits 44p and 44y, and to the integration process
 at the integration circuits 45p and 45y.
 Subsequently, in step S3, a check is made to find if the first flag F1 is
 set at "1". In the first cycle of loop, since the first flag F1 has been
 cleared to "0" in step S1, the answer in step S3 is negative (No), so that
 the flow proceeds to step S4. In step S4, the correction target values are
 outputted to drive the shift lens 7 so as to perform the correction of
 image shake during the image pickup operation.
 In the next step S5, a check is made to find if a request for communication
 is received from the mode microcomputer 32. If there is no request for
 communion the flow proceeds to step S7. If there is the request for
 communication, the flow proceeds to step S6. In step S6, a communication
 is performed, and the flow proceeds to step S7. More specifically, the
 communication in step S6 is performed between the driving amount control
 part 31 and the mode microcomputer 32 to exchange information on a request
 for turning-on/off of the image stabilizing operation, a request for
 turning-off of the power supply, a power-supply off flag FOFF for allowing
 turning-off of the power supply, etc.
 In step S7, a check is made through the communication with the mode
 microcomputer 32 to find if the request for turning-off of the power
 supply has been received. Incidentally, the presence or absence of the
 request for turning-off of the power supply is decided according to
 whether the power supply switch 33 is set in the off-state. If the answer
 in step S7 is affirmative (Yes), the flow proceeds to step SB. In step S8,
 a check is made to find if the second flag F2 is set at "1". In the first
 cycle of loop, since the second flag F2 has been cleared to "0" in step
 S1, the answer in step S8 is negative (No), so that the flow proceeds to
 step S9. In step S9, a check is made to find if the first flag F1 is set
 at "1". In the present cycle of loop, similarly, since the first flag F1
 has been cleared to "0" in step S1, the answer in step S9 is negative
 (No), so that the flow proceeds to step S10.
 In step S10, the target output value in the horizontal direction (yawing
 direction) is so set as to correspond to the central position of the shift
 lens 7. In the next step S11, the target output value in the vertical
 direction (pitching direction) is set to the predetermined value A. In
 this instance, the predetermined value A is such a value as not to make
 the outer circumferential portion of the lens holding frame 13 holding the
 shift lens 7 come into contact with the inner wall of the lens barrel 2.
 In the next step S12, the first flag F1 is set to "1", and the flow
 returns to step S2.
 With the first flag F1 set to "1", as described above, the answer in each
 of step S3 and step S9 becomes affirmative (Yes) in the next and
 subsequent cycles of loop. Therefore, the flow proceeds from step S9 to
 Step S13. In step S13, the predetermined value A is set to a value
 obtained by subtracting a minute amount .DELTA.A from the predetermined
 value A. In the next step S14, a check is made to find if the
 predetermined value A has reached a lowest limit value LMTA. If the answer
 in step S14 is negative (No), the flow proceeds to step S18. In step S18,
 the target output value in the vertical direction is set to the
 predetermined value A.
 Then, when the predetermined value A has reached the lowest limit value
 LMTA, the driving amount control part 31 decides that such an amount of
 movement as to make the lens holding frame 13 come into contact with the
 lens barrel 2 has been attained, and the flow proceeds to step S15. In
 step S15, the predetermined value A is set to the lowest limit value LMTA,
 and in step S16, the second flag F2 is set to "1". In the next step S17,
 the power-supply off flag FOFF for allowing turning-off of the power
 supply is set to "1", and the flow proceeds to step S18. In step S18, the
 target output value in the vertical direction is set to the predetermined
 value A (=LMTA), and the flow returns to step S2. By such a processing
 operation, the driving of the image pickup optical system 1 is made to
 stop.
 On the other hand, if it is determined in step S7 that the request for
 turning-off of the power supply is not received, the flow proceeds from
 step S7 to step S19. In step S19, a check is made to find if the first
 flag F1 is set at "1". If the answer in step S19 is negative (No), the
 flow returns to step S2. If the answer in step S19 is affirmative (Yes),
 the flow proceeds to step S20. In step S20, the first and second flags F1
 and F2 and the power-supply off flag FOFF are cleared to "0", and, in step
 S21, the image stabilizing operation is started. Specifically, the
 connection of the change-over switch 47 is changed over from the side of
 the predetermined-value output circuit 46 to the side of the integration
 circuits 45p and 45y, and the correction target values are outputted from
 the driving amount control part 31 to execute the control of the driving
 amount of the shift lens 7 during the image pickup operation. Then, the
 flow returns to step S2.
 FIG. 6 is a diagram showing the state where the lens holding frame 13 is
 being driven after the request for turning-off of the power supply is
 received. Referring to FIG. 6, when the request for tuning-off of the
 power supply has been received, the lens holding frame 13 moves from a
 position indicated by the solid line to a position indicated by the
 one-dot chain line (by the amount of movement A). After that, the lens
 holding frame 13 moves closer to the lens barrel 2 by the minute amount
 .DELTA.A, n times (.DELTA.A.times.n). Finally, the lens holding frame 13
 comes into contact with the lens barrel 2, as indicated by the two-dot
 chain line, and, after that, the power supply is turned off.
 As described above, according to the first embodiment, when the mode
 microcomputer 32 detects the off-state of the power supply switch 33, the
 driving amount control part 31 decides that the request for turning-off of
 the power supply is received, and causes the lens holding frame 13 to
 instantaneously move from the position of the optical axis 4 to the
 position corresponding to the setting value A. After that, the driving
 amount control part 31 causes the thus-moved lens holding frame 13 to
 gradually move to the vicinity of the inner wall of the lens barrel 2 and
 then to come into contact with the inner wall of the lens barrel 2.
 Therefore, it is possible to prevent the shift lens 7 which has been set
 into the floating state by the image stabilizing operation from dropping
 due to its own weight at the time of turning-off of the power supply to
 generate an unpleasant collision sound between the lens holding frame 13
 holding the shift lens 7 and the inner wall of the lens barrel 2.
 FIG. 7 is a block diagram showing the arrangement of an image pickup
 apparatus according to a second embodiment of the invention. In the image
 pickup apparatus according to the second embodiment, a driving amount
 control part 51 is provided with an image-stabilization turning-off switch
 52, and an electronic potentiometer (EVR) 53 is interposed between the
 amplifier 35 and the driving amount control part 51.
 More particularly, as shown in FIG. 8, the output terminal of the amplifier
 35 and the negative output terminal of the Hall element 11 are connected
 to the negative input terminal of the amplifier 35, while, to the positive
 input terminal of the amplifier 35, there are supplied the output signal
 from the positive output terminal of the Hall element 11, the reference
 voltage VREF and the output signal from the EVR 53.
 When the correction of image shaking is being performed with the power
 supply turned on, the output signal from the EVR 53 is supplied to the
 amplifier 35 in such a way as to compensate for the difference between the
 output signal of the Hall element 11 and the reference voltage VREF. On
 the other hand, when the request for turning-off of the power supply is
 issued with the power supply switch turned off, the output signal of the
 EVR 53 varies according to the request of the driving amount control part
 51 so as to adjust the offset of the output of the Hall element 11.
 FIG. 9 is a flow chart showing the operation of the image pickup apparatus
 according to the second embodiment. A program for effecting the operation
 of the image pickup apparatus according to the second embodiment is
 executed by the driving amount control part 51.
 After the processing operations in steps S1 to S9 are performed similarly
 to those in the first embodiment (FIG. 5), if the answer in step S9 is
 negative (No), the flow proceeds to step S31. In step S31, the
 image-stabilization turning-off switch 52 is forcibly turned off, since
 the request for turning-off of the power supply has been issued in step
 S7. Accordingly, the target output value in the horizontal direction
 (yawing direction) is so set as to correspond to the central position of
 the shift lens 7. In the next step S32, EVR initial data I is stored in a
 memory of the driving amount control part 51. More specifically, as
 described above, the EVR 53 is arranged to adjust the offset of the output
 signal of the Hall element 11. At the time of the initial setting, data
 obtained after adjustment of the offset, i.e., initial data I, is sent
 from the driving amount control part 51 to the EVR 53, and the initial
 data I is stored in the memory of the driving amount control part 51.
 Subsequently, in step S12, the first flag F1 is set to "1", and the flow
 returns to step S2.
 With the first flag F1 set to "1", as described above, the answer in each
 of step S3 and step S9 becomes affirmative (Yes) in the next and
 subsequent cycles of loop. Therefore, the flow proceeds from step S9 to
 Step S33. In step S33, a predetermined value C is set to a value obtained
 by subtracting a minute amount AD from the initial data I. In the next
 step S34, a check is made to find if the predetermined value C is a value
 not greater than a lowest limit value LMTC. If the answer in step S34 is
 negative (No), the flow proceeds to step S38. In step S38, the target
 output value in the vertical direction is set to the predetermined value
 C, which is sent to the EVR 53. After that, the above operation is
 repeated. As the output value from the EVR 53 becomes smaller gradually,
 the output of the amplifier 35 also becomes smaller gradually
 approximately in proportion to the output value from the EVR 53, so that
 the shift lens 7 gradually moves from the central position thereof to the
 inner wall of the lens barrel 2.
 Then, when the predetermined value C has reached the lowest limit value
 LMTC, the driving amount control part 51 decides that such an amount of
 movement as to make the lens holding frame 13 come into contact with the
 lens barrel 2 has been attained, and the flow proceeds to step S35. In
 step S35, the predetermined value C is set to the lowest limit value LMTC,
 and in step S36, the second flag F2 is set to "1". In the next step S37,
 the power-supply off flag FOFF for allowing turning-off of the power
 supply is set to "1", and the flow proceeds to step S38. In step S38, the
 target output value in the vertical direction is set to the predetermined
 value C (=LMTC), which is sent to the EVR 53, and the flow returns to step
 S2. By such a processing operation, the driving of the image pickup
 optical system 1 is made to stop.
 On the other hand, if it is determined in step S7 that the request for
 turning-off of the power supply is not received, the flow proceeds from
 step S7 to step S19. In step S19, a check is made to find if the first
 flag F1 is set at "1". If the answer in step S19 is negative (No), the
 flow returns to step S2. If the answer in step S19 is affirmative (Yes),
 the flow proceeds to step S39. In step S39, the initial data I in the
 vertical direction is sent to the EVR 53, and the flow proceeds to step
 S40. In step S40, the first and second flags F1 and F2 and the
 power-supply off flag FOFF are cleared to "0", and, in step S41, the image
 stabilizing operation is started. Specifically, the off-state of the
 image-stabilization turning-off switch 52 is canceled, and the correction
 target values are outputted from the driving amount control part 51 to
 execute the control of the driving amount of the shift lens 7 during the
 image pickup operation. Then, the flow returns to step S2.
 As described above, according to the second embodiment, when the mode
 microcomputer 32 detects a change-over to the off-state of the power
 supply switch 33, the driving amount control part 51 decides that the
 request for turning-off of the power supply is received, and causes the
 initial data I of the EVR 53 to be stored in the memory of the driving
 amount control part 51 so as to move the shift lens 7 on the basis of the
 initial data I. After that, the driving amount control part 51 controls
 the movement of the shift lens 7 on the basis of the setting value C
 (=I-.DELTA.D). Therefore, the output signal from the EVR 53 also becomes
 smaller gradually, and, accordingly, the output signal from the amplifier
 35 also becomes smaller approximately in proportion to the output signal
 from the EVR 53. As a result, the thus-moved lens holding frame 13
 gradually moves to the vicinity of the inner wall of the lens barrel 2 and
 then comes into contact with the inner wall of the lens barrel 2.
 Therefore, it is possible to prevent the shift lens 7 which has been set
 into the floating state by the image stabilizing operation from dropping
 due to its own weight at the time of turning-off of the power supply to
 generate an unpleasant collision sound between the lens holding frame 13
 holding the shift lens 7 and the inner wall of the lens barrel 2.
 FIG. 10 is a block diagram showing the arrangement of an image pickup
 apparatus according to a third embodiment of the invention. Referring to
 FIG. 10, the image pickup apparatus according to the third embodiment is
 provided with the driving amount control part 31 which is the same as that
 in the first embodiment, and the EVR 53 is interposed between the
 amplifier 35 and the driving amount control part 31. Further, the feedback
 signal from the amplifier 35 is fed back not only to the adder 36 but also
 to the driving amount control part 31.
 FIG. 11 is a flow chart showing the operation of the image pickup apparatus
 according to the third embodiment of the invention. A program for
 effecting the operation of the image pickup apparatus according to the
 third embodiment is executed by the driving amount control part 31.
 After the processing operations in steps S1 to S9 are performed similarly
 to those in the first and second embodiments (FIG. 5 and FIG. 9), if the
 answer in step S9 is negative (No), the flow proceeds to step S51. In step
 S51, the target output value in the horizontal direction is so set as to
 correspond to the central position of the shift lens 7. In the next step
 S52, the target output value in the vertical direction (pitching
 direction) is set to the predetermined value A. Then, in step S53, the EVR
 initial data I in the vertical direction (pitching direction) is stored in
 the memory of the driving amount control part 31. In the next step S54,
 the first flag F1 is set to "1", and the flow returns to step S2.
 With the first flag F1 set to "1", as described above, the answer in each
 of step S3 and step S9 becomes affirmative (Yes) in the next and
 subsequent cycles of loop. Therefore, the flow proceeds from step S9 to
 Step S55. In step S55, the output of the Hall element 11 is detected. In
 step S56, a check is made to find if the shift lens 7 (the lens holding
 frame 13) is located in the position of the inner wall of the lens barrel
 2. Specifically, if the theoretical position which the lens holding frame
 13 holding the shift lens 7 finally reaches happens to exceed the position
 of the inner wall of the lens barrel 2, the consumption of electric power
 would increase. Therefore, according to the third embodiment, the position
 of the shift lens 7 is always watched by means of the Hall element 11, so
 that it is made possible to cause the lens holding frame 13 to stop at the
 position of the inner wall of the lens barrel 2, thereby reducing the
 consumption of electric power.
 Then, if the answer in step S56 is negative (No), the flow proceeds to step
 S57. In step S57, the predetermined value A is set to a value obtained by
 subtracting a minute amount .DELTA.A from the predetermined value A. In
 the next step S58, a check is made to find if the predetermined value A
 has become not greater than a lowest limit value LMTA. If the answer in
 step S58 is negative (No), the flow proceeds to step S60. In step S60, a
 predetermined value C is set to a value obtained by subtracting a minute
 amount .DELTA.D from the initial data I. In the next step S61, a check is
 made to find if the predetermined value C is a value not greater than "0".
 If the answer in step S61 is negative (No), the flow proceeds to step S63.
 In step S63, the target output value in the vertical direction is set to
 the predetermined value A. In the next step S64, the predetermined value C
 is sent to the EVR 53, and the flow returns to step S2.
 On the other hand, if the answer in step S58 is affirmative (Yes), the flow
 proceeds to step S59. In step S59, the predetermined value A is set to the
 lowest limit value LMTA, and the flow proceeds to step 60, where the
 above-described processing operation is performed. Then, if the answer in
 step S61 becomes affirmative (Yes), the flow proceeds to step S62. In step
 S62, the predetermined value C is set to "0". Subsequently, the
 above-described processing operations in steps S63 and S64 are performed,
 and the flow returns to step S2.
 If the answer in step S56 is affirmative (Yes), i.e., when it is decided
 that the lens holding frame 13 has reached the inner wall of the lens
 barrel 2, the flow proceeds to step S65. In step S65, the second flag F2
 is set to "1". In the next step S66, the power-supply off flag FOFF is set
 to "1", and the flow returns to step S2.
 On the other hand, if it is decided in step S7 that there is no request for
 turning-off of the power supply, the flow proceeds to step S67. In step
 S67, a check is made to find if the first flag F1 is set at "1". If the
 answer in step S67 is negative (No), the flow returns to step S2. If the
 answer in step S67 is affirmative (Yes), the flow proceeds to step S68. In
 step S68, the initial data I in the vertical direction is sent to the EVR
 53. In the next step S69, the ordinary image stabilizing operation is
 performed. Then, in step S70, the first and second flags F1 and F2 and the
 power-supply off flag FOFF are cleared to "0", and the flow returns to
 step S2.
 As described above, according to the third embodiment, when there is the
 request for turning-off of the power supply, the movement of the shift
 lens 7 is controlled by using two values, i.e., the predetermined value A
 and the predetermined value C. The reason for this is as follows.
 If the magnification varying ratio of the variator lens 5 becomes a high
 value of 10.times. or more, as in the image pickup apparatuses in recent
 years, the so-called "remainder of image shake" becomes conspicuous during
 the ordinary image stabilizing operation in a case where the resolving
 power of the image pickup apparatus is not high. Therefore, if the image
 pickup apparatus is so set as to heighten the resolving power thereof with
 respect to the actually-usable moving range of the shift lens 7, there
 occur cases where, in the current image pickup apparatuses, it becomes
 impossible to cause the lens holding frame 13 to reach the inner wall of
 the lens barrel 2 however varied the output of the driving amount control
 part 31 is. Further, with regard to the offset, too, if the resolving
 power for operation of the shift lens 7 with respect to data to be sent to
 the EVR 53 is not heightened, in the case of the variator lens 5 having a
 high magnification varying ratio, the deviation of the optical axis 4 from
 the central axis of the image pickup optical system becomes conspicuous
 during the zooming operation even if the optical axis 4 slightly deviates.
 Accordingly, taking the above cases into consideration, it is necessary to
 heighten the resolving power for operation of the shift lens 7. In this
 case, too, however, there is a case where the lens holding frame 13
 becomes unable to reach the inner wall of the lens barrel 2 no matter how
 varied the output of the EVR 53 is.
 Therefore, according to the third embodiment, the predetermined value A and
 the predetermined value C are used to control the shift lens 7 upon
 receipt of the request for turning-off of the power supply.
 Further, when the mode microcomputer 32 detects a change-over to the
 off-state of the power supply switch 33, the driving amount control part
 31 decides that the request for turning-off of the power supply is
 received, and causes the initial data I of the EVR 53 to be stored in the
 memory of the driving amount control part 31 so as to move the shift lens
 7 on the basis of the initial data I. After that, the driving amount
 control part 31 controls the movement of the shift lens 7 on the basis of
 the setting value C (=I-.DELTA.D), so that the thus-moved lens holding
 frame 13 gradually moves to the vicinity of the inner wall of the lens
 barrel 2 and then comes into contact with the inner wall of the lens
 barrel 2. Therefore, it is possible to prevent the shift lens 7 which has
 been set into the floating state by the image stabilizing operation from
 dropping due to its own weight at the time of turning-off of the power
 supply to generate an unpleasant collision sound between the lens holding
 frame 13 holding the shift lens 7 and the inner wall of the lens barrel 2.
 FIG. 12 is a block diagram showing the arrangement of a control system of
 an image pickup apparatus according to a fourth embodiment of the
 invention. Referring to FIG. 12, the image pickup apparatus is provided
 with the above-mentioned image pickup optical system 1, a vibration signal
 forming circuit 130 arranged to detect the vibration of the body of the
 image pickup apparatus to form vibration signals, a driving amount control
 part 131 arranged to control the amounts of driving of the shift lens 7 on
 the basis of outputs of the vibration signal forming circuit 130, etc., a
 mode microcomputer 132 arranged to watch the operation state of the image
 pickup apparatus body, a power supply switch 133 arranged to be operated
 to start the power supply of the image pickup apparatus body, a main
 microcomputer 134 arranged to control the whole image pickup apparatus,
 D/A converters 135p and 135y arranged to convert the digital signals
 outputted from the driving amount control part 131 into analog signals,
 amplifiers 136p and 136y arranged to amplify the output signals of the
 Hall elements 11p and 11y, adders 137p and 137y arranged to add the
 feedback signals from the amplifiers 136p and 136y to the output signals
 of the D/A converters 135p and 135y, driving circuits 138p and 138y
 arranged to drive the voice coil motors 10p and 10y on the basis of the
 output signals of the adders 137p and 137y, an image processing circuit
 139 arranged to perform predetermined image processing on an electrical
 signal obtained by the photoelectric conversion by the image sensor 9, an
 output terminal 140 arranged to output image data processed by the image
 processing circuit 139 to a display device (not shown) such as an LCD, and
 a recorder 141 arranged to record the processed image data on a recording
 medium such as a magnetic tape.
 The vibration signal forming circuit 130, more particularly, includes
 angular velocity sensors 142p and 142y disposed at appropriate portions of
 the image pickup optical system 1 to detect the vibration angles of the
 image pickup apparatus body, high-pass filters (HPFs) 143p and 143y
 arranged to remove DC components from the detection signals outputted from
 the angular velocity sensors 142p and 142y, amplifiers 144p and 144y
 arranged to amplify the output signals of the HPFs 143p and 143y, and
 low-pass filters (LPFs) 145p and 145y arranged to remove predetermined
 high-frequency components from the output signals of the amplifiers 144p
 and 144y to form the vibration signals.
 The image processing circuit 139 includes a camera signal processing
 circuit 146 arranged to perform predetermined image pickup processing on
 the electrical signal obtained by the photoelectric conversion by the
 image sensor 9 to form a camera signal, a video signal processing circuit
 147 arranged to perform predetermined video processing on the camera
 signal outputted from the camera signal processing circuit 146 to form a
 video signal or to convert the formed video signal into an RF (radio
 frequency) signal and output the RF signal to the recorder 141, and an
 output signal change-over circuit 148 arranged to change over output
 signals.
 The output signal change-over circuit 148 includes, as shown in FIG. 13, a
 signal generator 149 arranged to generate a black signal as a
 predetermined luminance level signal, and a change-over switch 150. To the
 contact "a" of the change-over switch 150 is supplied the video signal, to
 the contact "b" of the change-over switch 150 is supplied the black signal
 from the signal generator 149, and to the contact "c" of the change-over
 switch 150 is supplied an output signal of the main microcomputer 134.
 According to the above arrangement, the contact "c" of the change-over
 switch 150 is connected to the contact "a" or the contact "b" depending on
 the output signal of the main microcomputer 134, so that the video signal
 or the black signal is outputted from the output signal change-over
 circuit 148. Incidentally, while in the fourth embodiment the
 predetermined luminance level signal to be outputted from the signal
 generator 149 is a black signal, it may be changed to a particular color
 signal, such as a white signal, other than the black signal.
 Further, the driving amount control part 131 includes, as shown in FIG. 14,
 A/D converters 151p and 151y arranged to convert the analog vibration
 signals outputted from the vibration signal forming circuit 130 into
 digital vibration signals, HPFs 152p and 152y arranged to remove
 predetermined low-frequency components from the output signals of the A/D
 converters 151p and 151y, phase/gain correcting circuits 153p and 153y
 arranged to correct the phase and/or gain of the output signals of the
 HPFs 152p and 152y, integration circuits 154p and 154y arranged to
 integrate the output signals of the phase/gain correcting circuits 153p
 and 153y to form correction target values for correcting the image shake,
 a predetermined-value output circuit 155 arranged to output a
 lens-movement target value (a predetermined value X) which is desired
 irrespective of the vibration signals from the vibration signal forming
 circuit 130, and a change-over switch 156 arranged to change over the
 output signals of the integration circuits 154p and 154y and the output
 signal of the predetermined-value output circuit 155. The contact "a" of
 the change-over switch 156 is connected to the integration circuits 154p
 and 154y, the contact "b" of the change-over switch 156 is connected to
 the predetermined-value output circuit 155, and the contact "c" of the
 change-over switch 156 is connected to the mode microcomputer 132. Then,
 the contact "c" of the change-over switch 156 is connected to the contact
 "a" or the contact "b" depending on the signal from the mode microcomputer
 132, which watches the state of the power supply switch 133, so that the
 correction target values from the integration circuits 154p and 154y or
 the predetermined value X from the predetermined-value output circuit 155
 is outputted from the change-over switch 156.
 In the image pickup apparatus having the above construction, when the power
 supply switch 133 is turned on, the mode microcomputer 132 notifies the
 main microcomputer 134 of the turning-on of the power supply switch 133.
 The main microcomputer 134 decides the power supply to have been turned on
 and starts its control operation.
 Then, when the angular velocity sensors 142p and 142y detect the vibration
 of the image pickup apparatus body, the HPFs 143p and 143y, the amplifiers
 144p and 144y and the LPFs 145p and 145y perform predetermined processing
 to form vibration signals. The formed vibration signals are supplied to
 the driving amount control part 131. In the driving amount control part
 131, correction target values are calculated via the A/D converters 151p
 and 151y, the HPFs 152p and 152y, the phase/gain correcting circuits 153p
 and 153y and the integration circuits 154p and 154y. The calculated
 correction target values are outputted to the D/A converters 135p and 135y
 via the change-over switch 156.
 Subsequently, the correction target values, which have been converted into
 analog signals by the D/A converters 135p and 135y, are supplied to the
 adders 137p and 137y, where the analog correction target values are added
 to the feedback signals supplied from the Hall elements 11p and 11y via
 the amplifiers 36p and 36y. Then, the output signals of the adders 137p
 and 137y are supplied to the driving circuits 138p and 138y. The driving
 circuits 138p and 138y issue driving signals to the voice coil motors 10p
 and 10y to two-dimensionally drive the shift lens 7 in the vertical
 direction and in the horizontal direction within a plane perpendicular to
 the optical axis 4 during the image pickup operation on an object image.
 The object image as being picked up is formed on the image sensor 9 so as
 to be photoelectrically converted into an electrical signal. The
 electrical signal obtained by the photoelectric conversion is supplied to
 the output terminal 140 via the camera signal processing circuit 146, the
 video signal processing circuit 147 and the output signal change-over
 circuit 148, in turn. The electrical video signal outputted from the
 output terminal 140 is supplied to a display device such as an LCD so as
 to be displayed as a visual video image. Further, the RF signal obtained
 by the video signal processing circuit 147 is sent to the recorder 141 and
 is then recorded on a recording medium such as a magnetic tape.
 On the other hand, when the power supply switch 133 is changed over from
 the on-state to the off-state, a notice of the change-over of the state of
 the power supply switch 133 is given to the mode microcomputer 132 and,
 then, to the main microcomputer 134. The main microcomputer 134, which has
 received such a notice from the mode microcomputer 132, restrains the
 video signal processing circuit 147 from outputting the RF signal, thereby
 stopping the recording operation of the recorder 141, and, at the same
 time, notifies the contact "c" of the change-over switch 150 of the output
 signal change-over circuit 148 that the power supply switch 133 has been
 turned off. Accordingly, the connection of the contact "c" of the
 change-over switch 150 is changed over from the contact "a" to the contact
 "b", so that the output terminal 140 is made to be supplied with the black
 signal from the signal generator 149.
 Subsequently, after the lapse of a predetermined period of time since the
 power supply switch 133 has been changed over from the on-state to the
 off-state, the connection of the change-over switch 156 of the driving
 amount control part 131 is changed over from the side of the integration
 circuits 154p and 154y to the side of the predetermined-value output
 circuit 155. Specifically, since, even if the power supply switch 133 is
 changed over from the on-state to the off-state, it takes a predetermined
 period of time (for example, 20 V (vertical synchronizing period) (about
 16.7 msec in NTSC, or about 20 msec in )) to completely stop the
 recording operation of the recorder 141 on the RF signal supplied from the
 video signal processing circuit 147, it is after the lapse of such a
 predetermined period of time that the connection of the change-over switch
 156 of the driving amount control part 131 is changed over from the side
 of the integration circuits 154p and 154y to the side of the
 predetermined-value output circuit 155. Accordingly, the predetermined
 value X, instead of the correction target values, is outputted from the
 driving amount control part 131, so that the shift lens 7 is made to be
 driven on the basis of the predetermined value X.
 FIG. 15 is a flow chart showing the lens-position control method according
 to the fourth embodiment of the invention. A program for the lens-position
 control method is executed by the driving amount control part 131.
 Referring to FIG. 15, in step S101, the whole system is initialized. By
 this initializing process, first to third flags F1 to F3, which will be
 described later, are cleared to "0".
 In the next step S102, the flow waits for the vertical scanning operation
 to be synchronized. By this vertical synchronization, processing
 operations subsequent to step S102 are performed once per field.
 In step S103, the driving amount control part 131 makes communication with
 the mode microcomputer 132. More specifically, the driving amount control
 part 131 exchanges, with the mode microcomputer 132, information on a
 request for turning-on/off of the image stabilizing operation, a request
 for turning-off of the power supply, a power-supply off flag FOFF for
 allowing turning-off of the power supply, etc.
 In the next step S104, a check is made through the communication with the
 mode microcomputer 132 to find if the request for turning-off of the power
 supply has been received. If the answer in step S104 is affirmative (Yes),
 the flow proceeds to step S105. In step S105, a check is made to find if
 the first flag F1 is set at "1". In the first cycle of loop, since the
 first flag F1 has been cleared to "0" in step S101, the answer in step
 S105 is negative (No), so that the flow proceeds to step S106. In step
 S106, a count value CN of a counter incorporated in the driving amount
 control part 131 is incremented by one, and the flow proceeds to step
 S107. In step S107, a check is made to find if the count value C is not
 less than a setting value C. In this instance, the setting value C is a
 value equivalent to a predetermined period of time required for the lapse
 of 20 V (about 16.7 msec in NTSC or about 20 msec in ) according to the
 recording operation state of the recorder 141 upon receipt of the request
 for turning-off of the power supply. If the answer in step S107 is
 negative (No), the flow returns to step S102 to repeat the above
 processing operation until the count value CN of the counter reaches the
 setting value C, i.e., the predetermined period of time elapses. When the
 count value CN of the counter reaches the setting value C, the flow
 proceeds from step S107 to step S108. In step S8, the first flag F1 is set
 to "1", and the flow returns to step S102.
 With the first flag F1 set to "1", as described above, the answer in step
 S105 becomes affirmative (Yes). Therefore, the flow proceeds to step S109
 to stop the image stabilizing operation. Specifically, the connection of
 the change-over switch 156 is changed over from the side of the
 integration circuits 154p and 154y to the side of the predetermined-value
 output circuit 155.
 Subsequently, in step S110, a check is made to find if the second flag F2
 is set at "1". In this cycle of loop, since there is maintained the state
 where the second flag F2 has been set to "0" in step S101, the answer in
 step S110 is negative (No), and the flow proceeds to step S111. In step
 S111, a check is made to find if the third flag F3 is set at "1". In this
 cycle of loop, also, since there is maintained the state where the third
 flag F3 has been set to "0" in step S101, the answer in step S111 is
 negative (No), and the flow proceeds to step S112. In step S112, the
 predetermined value X is set to a value "R". In this instance, the value
 "R" is such a value as not to make the outer circumferential portion of
 the lens holding frame 13 holding the shift lens 7 come into contact with
 the inner wall of the lens barrel 2.
 In the next step S113, the third flag F3 is set to "1", and the flow
 proceeds to step S119. In step S119, the predetermined value X is
 outputted as an output value OUT of the driving amount control part 131,
 and the flow returns to step S102. By the above processing operation, the
 lens holding frame 13 is made to instantaneously move up to the vicinity
 of the inner wall of the lens barrel 2.
 With the third flag F3 set to "1", as described above, the answer in step
 S111 becomes affirmative (Yes) in the next and subsequent cycles of loop.
 Therefore, the flow proceeds from step S111 to Step S114. In step S114,
 the predetermined value X is set to a value obtained by subtracting a
 minute amount AR from the predetermined value X. In the next step S115, a
 check is made to find if the predetermined value X has become a value not
 greater than a lowest limit value LLMT. If the answer in step S115 is
 negative (No), the flow proceeds to step S119. In step S119, the
 predetermined value X (=X-.DELTA.R) is outputted as the output value OUT
 of the driving amount control part 131, and the flow returns to step S2.
 Then, the above processing operation is repeated until the predetermined
 value X reaches the lowest limit value LLMT. When the predetermined value
 X has become not greater than the lowest limit value LLMT, the driving
 amount control part 131 decides that such an amount of movement as to make
 the lens holding frame 13 come into contact with the lens barrel 2 has
 been attained, and the flow proceeds to step S116. In step S116, the
 predetermined value X is set to the lowest limit value LLMT, and in step
 S117, the second flag F2 is set to "1". In the next step S118, the
 power-supply off flag FOFF for allowing turning-off of the power supply is
 set to "1", and the flow proceeds to step S119. In step S119, the
 predetermined value X is outputted as the output value OUT of the driving
 amount control part 131, and the flow returns to step S102. By such a
 processing operation, the driving of the image pickup optical system 1 is
 made to stop.
 On the other hand, if it is determined in step S104 that the request for
 turning-off of the power supply is not received, i.e., if the power supply
 switch 133 is not turned off, the flow proceeds from step S104 to step
 S20. In step S120, the count value CN of the counter is cleared to "0". In
 the next step S121, a check is made to find if the first flag F1 is set at
 "1". If the answer in step S121 is negative (No), the flow returns to step
 S102. If the answer in step S121 is affirmative (Yes), the flow proceeds
 to step S122. In step S122, the first to third flags F1 to F3 are cleared
 to "0". In the next step S123, the power-supply off flag FOFF is cleared
 to "0", and, in step S124, the image stabilizing operation is started.
 Then, the flow returns to step S102. Specifically, the connection of the
 change-over switch 156 is changed over from the side of the
 predetermined-value output circuit 155 to the side of the integration
 circuits 154p and 154y, and the correction target values are outputted
 from the driving amount control part 131 to execute the control of the
 driving amount of the shift lens 7 during the image pickup operation.
 FIG. 16 is a diagram showing the state where the lens holding frame 13 is
 being driven after the request for turning-off of the power supply is
 received. Referring to FIG. 16, when a predetermined period of time
 equivalent to, for example, 20 V has elapsed after the receipt of the
 request for tuning-off of the power supply, the lens holding frame 13
 moves from a position indicated by the solid line to a position indicated
 by the one-dot chain line (by the amount of movement R). After that, the
 lens holding frame 13 moves closer to the lens barrel 2 by the minute
 amount .DELTA.R, n times (.DELTA.R.times.n). Finally, the lens holding
 frame 13 comes into contact with the lens barrel 2, as indicated by the
 two-dot chain line, and, after that, the power supply is turned off.
 As described above, according to the fourth embodiment, when the mode
 microcomputer 132 gives notice of the change-over to tuning-off of the
 power supply switch 133, the main microcomputer 134 stops the recording
 operation of the recorder 141 and changes over the connection of the
 output signal change-over circuit 148 from the side of the video signal
 processing circuit 147 to the side of the signal generator 149 so as to
 output the black signal. Subsequently, after the lapse of a predetermined
 period of time, the lens holding frame 13 is instantaneously moved from
 the position of the optical axis 4 to the position corresponding to the
 setting value R. After that, the thus-moved lens holding frame 13 is
 gradually moved to the vicinity of the inner wall of the lens barrel 2 and
 is then made to come into contact with the inner wall of the lens barrel
 2. Therefore, it is possible to prevent the shift lens 7 which has been
 set into the floating state by the image stabilizing operation from
 dropping due to its own weight at the time of turning-off of the power
 supply to generate an unpleasant collision sound between the lens holding
 frame 13 holding the shift lens 7 and the inner wall of the lens barrel 2.
 Further, it is possible to prevent an unnatural video image motion caused
 by the deviation of the optical axis 4 during the process of movement of
 the shift lens 7 at the time of turning-off of the power supply from being
 outputted to a display device or being recorded on a magnetic tape.
 Incidentally, the invention is not limited to the above embodiments. While
 in the above embodiments it is decided that the request for turning-off of
 the power supply has been issued when the change-over to the off-state of
 the power supply switch has been detected, it may be decided that the
 request for turning-off of the power supply has been issued when the
 remaining amount of a battery mounted in the image pickup apparatus has
 become less than a predetermined value.
 Further, according to a fifth embodiment of the invention, for example, the
 main microcomputer 134 always watches the recorder 141, and, when the mode
 microcomputer 132 has detected the request for turning-off of the power
 supply, the driving amount control part 131 changes the change-over timing
 of the change-over switch 156 according the recording operation state of
 the recorder 141.
 FIGS. 17(a) to 17(e) are timing charts showing the operation at the time of
 turning-off of the power supply in the fifth embodiment of the invention.
 When the power supply switch 133 is turned off at a point of time t1 (FIG.
 17(a)), the mode microcomputer 132 notifies the main microcomputer 134 and
 the driving amount control part 131 of the turning-off of the power supply
 switch 133 at a point of time t2 (FIG. 17(b)).
 Then, in a case where the recorder 141 is in the process of recording a
 video signal on a magnetic tape, the main microcomputer 134 detects the
 stoppage of the recording mode at a point of time t4 at which a
 predetermined period of time T required for the completion of the stopping
 operation has elapsed (FIG. 17(c)). At the same time, the connection of
 the changeover switch 156 of the driving amount control part 131 is
 changed over to the side of the predetermined-value output circuit 155,
 and the control operation of the driving amount of the shift lens 7 at the
 time of turning-off of the power supply is performed (FIG. 17(d)). Then,
 at a point of time t5 at which the lens holding frame 13 holding the shift
 lens 7 has come into contact with the inner wall of the lens barrel 2 to
 terminate the control operation of the driving amount of the shift lens 7,
 the power-supply off flag FOFF is set to "1" to output an instruction for
 allowing the turning-off of the power supply (FIG. 17(e)).
 On the other hand, in a case where the recorder 141 is not performing the
 recording operation, for example, when the recorder 141 is not loaded with
 any magnetic tape, it is not necessary to wait for the predetermined
 period of time T, because the predetermined period of time T is a waiting
 time required for ending the recording operation of the recorder 141 on
 the magnetic tape at the time of turning-off of the power supply.
 Accordingly, in this case, at the same time that the mode microcomputer
 132 notifies the main microcomputer 134 and the driving amount control
 part 131 of the turning-off of the power supply switch 133 at the point of
 time t2 (FIG. 17(b)), the main microcomputer 134 detects the stoppage of
 the recording mode, as indicated by a broken line in FIG. 17(c), and
 starts the control operation of the movement of the shift lens 7 at the
 point of time t2, as indicated by a broken line in FIG. 17(d). Then, at a
 point of time t3 at which the lens holding frame 13 has come into contact
 with the inner wall of the lens barrel 2 to end the control operation of
 the movement of the shift lens 7, the power-supply off flag FOFF is set to
 "1" to output an instruction for allowing the turning-off of the power
 supply, as indicated by a broken line in FIG. 17(e).
 As described above, the main microcomputer 134 always watches the recorder
 141, and, if the recorder 141 is not in the process of the recording
 operation when the mode microcomputer 132 has detected the request for
 turning-off of the power supply, the control operation of the movement of
 the shift lens 7 can be started earlier. Accordingly, the time for turning
 off the power supply can be made earlier, so that the effect of electric
 power saving can be obtained.
 The individual components shown in schematic or block form in the drawings
 are all well-known in the camera arts and their specific construction and
 operation are not critical to the operation or best mode for carrying out
 the invention.
 While the present invention has been described with respect to what is
 presently considered to be the preferred embodiments, it is to be
 understood that the invention is not limited to the disclosed embodiments.
 To the contrary, the invention is intended to cover various modifications
 and equivalent arrangements included within the spirit and scope of the
 appended claims. The scope of the following claims is to be accorded the
 broadest interpretation so as to encompass all such modifications and
 equivalent structures and functions.
 For example, while in the above-described embodiments an image-shake
 preventing lens is made to gradually come into contact with a
 movable-range end by controlling the position of the image-shake
 preventing lens when an image-shake preventing operation is ended, the
 image-shake preventing lens may be made to gradually come into contact
 with the movable-range end by gradually removing a driving force for
 floating the image-shake preventing lens.
 Further, a movable unit for image-shake prevention according to the
 invention is not limited to a lens, and may be another movable unit for
 image-shake prevention, such as an image pickup part.
 Further, the software arrangement and the hardware arrangement in each of
 the embodiments may be adaptively replaced with each other.
 Further, in the invention, the embodiments described above or the technical
 elements thereof may be combined with each other according to necessity.
 Further, the invention also applies to cases where each claim or the whole
 or a part of the arrangement of each of the embodiments constitutes one
 apparatus or is used in combination with another apparatus or as a
 component element of an apparatus.
 Further, the invention is also applicable to various types of cameras, such
 as an electronic still camera, a video camera and a camera using a
 silver-halide film, various image pickup apparatuses other than cameras,
 various optical apparatuses and other types of apparatuses, and, moreover,
 to apparatuses adapted for the cameras, the image pickup apparatuses,
 optical apparatuses and the other types of apparatuses, and elements
 constituting the above-mentioned apparatuses.