Optical apparatus having image-blur correction/reduction system

At least one exemplary embodiment is directed to an image-blur correction/reduction system miniaturized by arranging support guiding devices of a movable member and a rotation restricting device configured for restricting the rotation of the movable member about the optical axis so as to overlap each other viewed from the optical axial direction, a lens barrel, which can have the image-blur correction/reduction system, and an optical apparatus, which can have the same.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image-blur correction/reduction system and an optical apparatus having the image-blur correction/reduction system.

2. Description of the Related Art

During handhold shooting, for preventing or reducing image blur due to camera shake, optical apparatuses (e.g., a digital camera, and a video camera) equipped with an image-blur correction/reduction system have been used.

The camera shake is detected by a shake detecting device so as to optically or electronically correct and/or reduce the camera shake corresponding to the detected result.

An optical image-blur correction/reduction system includes a scheme in that a correction lens held on a movable member is displaced in the yaw or the pitch direction so as to correct and/or reduce the camera shake.

For example, an image-blur correction/reduction system constructed as below is discussed in Japanese Patent Publication No. 3229899.

Three abutment parts abutting the movable member that moves on a plane perpendicular to the optical axis are provided on a base member.

For restricting the position of the movable member in the optical axial direction with the three abutment parts while restricting the movable member from rotating about the optical axis by a rotation restricting device, a structure shown inFIG. 12is adopted.

Referring toFIG. 12, reference numeral11denotes a support frame; numeral545a correction lens; numeral547a fixed frame; numeral550a first holding frame; and numeral558a part of a housing formed integrally with the support frame11.

A pitch shaft549pis for displacing the correction lens545in the pitch direction and a bearing548pis the bearing of the pitch shaft549p.

A yaw shaft549yis for displacing the correction lens545in the yaw direction and a bearing548yis the bearing of the yaw shaft549y.

Three support parts12a,12b, and12c, each of which can have a recess, are provided in the support frame11.

These recesses are to be fitted to hatched protrusions547a,547b, and547cof the fixed frame547, respectively.

Thereby, the fixed frame547is surrounded by three points of the support parts12a,12b, and12cso as to define the plane of the movable member including the correction lens, thereby precisely defining the moving direction and the inclination to the optical axis of the movable member.

Also, the first holding frame550, the bearings548pand548ysupported by the housing558, the pitch shaft549p, and the yaw shaft549y, which are mentioned above, have functions of restricting the rotation of the movable member about the optical axis.

In the system discussed in Japanese Patent Publication No. 3229899, although the moving direction and the inclination to the optical axis of the movable member including the correction lens can be precisely defined, a problem can arise when a lens barrel is miniaturized.

That is, the three abutment parts for restricting the position of the movable member in the optical axial direction and the rotation restricting device configured for suppressing the rotation of the movable member about the optical axis can be arranged in different positions viewed from the optical axial direction, so that the miniaturization of the lens barrel in diameter is suppressed.

SUMMARY OF THE INVENTION

The present invention provides is directed to a support guiding device of a movable member configured for restricting the position of the movable member in the optical axial direction so as to guide the movable member in a plane direction perpendicular to the optical axis and a rotation restricting device configured for restricting the rotation of the movable member about the optical axis, which can be arranged so as to overlap each other viewed from the optical axial direction.

By the arrangement in such a manner, an image stabilizer and an optical apparatus, which can have the image stabilizer, can be miniaturized.

DESCRIPTION OF THE EMBODIMENTS

Processes, techniques, apparatus, and materials as known by one of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the enabling description where appropriate, for example the fabrication of the lens elements and their materials.

In all of the examples illustrated and discussed herein any specific values should be interpreted to be illustrative only and non limiting. For example some members may be indicated as being fixed to other elements; however these members can be operatively connected to the elements as well. Thus, other examples of the exemplary embodiments could have different values.

Notice that similar reference numerals and letters refer to similar items in the following figures, and thus once an item is defined in one figure, it may not be discussed for following figures.

First Exemplary Embodiment

A first exemplary embodiment exemplifies a shift unit provided for correcting or reducing image blur in a third lens group of a lens barrel, which can have a four-group variable power optical system of convex-concavo-convex-convex first to fourth lens groups. First, the entire configuration of the lens barrel will be described with reference toFIGS. 1 and 2.FIG. 1is an exploded perspective view of the lens barrel according to the embodiment;FIG. 2is a sectional view of part of the lens barrel; and in these drawings, some shapes are omitted for the sake of description convenience.

Referring toFIGS. 1 and 2, reference character L1denotes a fixed first lens group; character L2a second lens group performing variation by moving in the optical axial direction; and character L3a third lens group correcting or reducing image blur by moving on a plane perpendicular to the optical axis. The third lens group L3includes a 3ath lens group L3aand a 3bth lens group L3b. Character L4denotes a fourth lens group which can focus by moving in the optical axial direction. Also, reference numeral1represents a front-lens barrel holding the first lens group L1; numeral2a variable power movement frame holding the second lens group L2; numeral3a shift unit movable on a plane perpendicular to the optical axis; numeral4a focusing movement frame holding the fourth lens group L4; and numeral5a fixed barrel with the front end connected to the front-lens barrel (e.g., with three screws). Reference numeral6denotes a rear-lens barrel having an image-pickup element601, such as a CCD or CMOS, fixed thereto; and numeral602an intermediate member for attaching the image-pickup element601to the rear-lens barrel6.

The rear-lens barrel6, which is positioned to the fixed barrel5and which can have the shift unit3caught therein, is fixed from the front side with two screws and one engagement part (an engaging claw603and an engaging hole501). The intermediate member602is fixed to the rear-lens barrel6with screws after fixing the image-pickup element601thereto with an adhesive. The shift unit3is sandwiched between the fixed barrel5and the rear-lens barrel6, and fixed from the front side with two screws. A light-amount adjustment unit7includes a press strip701, two diaphragm blades702and703, a partition strip704, a diaphragm bottom board705, an ND (neutral density) filter706, an ND bottom board707, a diaphragm arm708, an ND arm709, and screws710, FPC (Flexible print circuit)711. In the light-amount adjustment unit7, by moving the two diaphragm blades702and703in opposition to each other on the plane perpendicular to the optical axis, an aperture is changed. The light-amount adjustment unit7is fixed to the shift unit3with the screws710. The ND filter706having two-density parts can move back and forth independently of the diaphragm blades702and703.

Both ends of a guide bar8are held by the fixed barrel5and the rear-lens barrel6, respectively, and a guide bar9is pressed into the fixed barrel5. Both ends of guide bars10and11are held by the rear-lens barrel6and the shift unit3, respectively. The variable power movement frame2and the focusing movement frame4are supported by the guide bars8and9and the guide bars10and11, respectively, movably in the optical axial direction. The variable power movement frame2and the focusing movement frame4are restricted from falling down in the optical axial direction by fitting into one guide bar with a sleeve, which can have a predetermined length in the optical axial direction, respectively. They are also restricted from rotating about the one guide bar by engaging the other guide bar with a U-shaped groove, respectively.

A stepping motor (also referred to as a zoom motor below)200moves the second lens group L2in the optical axial direction as a variator, and it includes a rotor201and a coaxial lead screw202, which is mated with a rack203provided in the variable power movement frame2. By the rotation of the rotor201and the lead screw202, the variable power movement frame2(the second lens group L2) is driven in the optical axial direction. The stepping motor200is fixed across the fixed barrel5and the rear-lens barrel6with two screws. With a helical torsion coil spring204arranged between the variable power movement frame2and the rack203, the variable power movement frame2is urged toward the guide bars8and9in the radial direction of the guide bars while the rack203is urged toward the variable power movement frame2in the optical axial direction. Furthermore, the rack203is urged in the engaging direction with the lead screw202.

A zoom reset switch205made of a photo-interrupter is for detecting the reference position of the second lens group L2by electrically detecting the change in light exclusion/transmission due to the movement in the optical axial direction of a light-exclusion part206formed in the variable power movement frame2. The zoom reset switch205is fixed to the fixed barrel5with screws. A focus motor (voice coil motor)400moves the fourth lens group L4in the optical axial direction for focusing, and it includes a coil401, a drive magnet402, and two yokes403aand403b. By passing an electric current through the coil401, a Lorentz force is generated due to the repulsion of magnetic lines against each other generated between the coil401and the magnet402so as to move the fourth lens group L4. The focusing movement frame4includes a sensor magnet (not shown) multipolarized in the optical axial direction. An MR sensor404is retained at a position of the fixed barrel5opposing the sensor magnet and the outside of the optical axis. A predetermined reference position of the fourth lens group L4can be detected using the signal from the MR sensor404.

Then, the configuration of the shift unit3will be described with reference toFIGS. 3 to 6B.FIG. 3is an exploded view of the shift unit3viewed from the image plane;FIG. 4is an exploded perspective view of the shift unit3; andFIG. 5is a sectional view of the shift unit3and the light-amount adjustment unit7. The shift unit3includes a shift magnet unit31, a shift base unit32, and a shift movement frame unit33. The shift base unit32is arranged between the shift magnet unit31and the shift movement frame unit33. The shift magnet unit31and the shift movement frame unit33constitute a movable member by being integrated with screws301in this state (referred to as a movable unit34below when they are integrally expressed). The movable unit34is movable relative to the shift base unit32in the yaw direction or the pitch direction in the state holding the third lens group L3.

First and second shift barrels331and332constitute the shift movement frame unit. The first shift barrel331holds a 3 ath lens group L3aand the second shift barrel332holds a 3 bth lens group L3b. The first shift barrel331includes a lens holder331aholding the 3 ath lens group L3aand a connection part331bconnecting the second shift barrel332. The first shift barrel331and the second shift barrel332are fixed together (e.g., with an adhesive) after eliminating the relative eccentricity. The second shift barrel332is bonded to the connection part331bof the first shift barrel331. The space in the optical axial direction between the 3 ath lens group L3aand the 3 bth lens group L3bis constant. A magnet base311and a metallic plate312and magnet314pand314yconstitute the shift magnet unit31. The surface of the magnet base311adjacent to the image plane is in contact with the surface of the metallic plate312adjacent to the front lens in the optical axial direction. The suitable material for the metallic plate312can vary (e.g., stainless steel).

A shift base321is included in the shift base unit32, and can be fixed by being clamped between the fixed barrel5and the rear-lens barrel6. Metallic plates322ato322care included in the shift base unit32, and can be arranged in recesses321ato321cprovided in the shift base321, respectively. The suitable material for the metallic plates322ato322ccan also vary (e.g., stainless steel). Three balls323ato323care clamped between the metallic plates322ato322cand the metallic plate312, respectively. These balls323ato323care made of low magnetic reactive material (e.g., stainless steel) so as not to be attracted by a magnet arranged in the vicinity.

The three balls323ato323cabut the metallic plates322ato322c, respectively, and they further abut upper surfaces312ato312cof the metallic plate312, respectively. The respective three abutment surfaces are roughly perpendicular to the optical axis of the optical system. When the diameters of the three balls323ato323care the same, reducing the relative difference in position of the abutment surfaces in the optical axial direction enables the movable unit34to be held and shift-guided in the perpendicular direction to the optical axis. An L-shaped shaft302is formed by bending a cylindrical bar at about 90°, and is included in the rotation restricting device. The suitable material for the L-shaped shaft302can vary (e.g., stainless steel). The L-shaped shaft302is assembled into a support part provided in the magnet base311or the first shift barrel331after being assembled in the pitch direction into a support part provided the shift base321when the shift magnet unit31is integrated with the shift movement frame unit33.

Then, the driving device of the shift unit3will be described. The driving device and the position detecting device in the pitch direction and the yaw direction can have the same configuration, and can have the phase difference of 90° about the optical axis. Hence, only the driving device in the pitch direction will be described herein and device in the yaw direction will not be described. In the drawings, the reference numerals in the pitch direction are attached by “p” while numerals in the yaw direction are attached by “y.” A drive magnet313pis radially bipolarized in the optical axial direction, and it also serves as a position detector. A back yoke314pis for closing the magnetic flux of the magnet313padjacent to the front lens in the optical axial direction; numeral324pdenotes a coil; and a yoke325pis for closing the magnetic flux of the magnet313padjacent to the image plane in the optical axial direction. The yoke325phas substantially the same projection shape as that of the magnet313pin the optical axial direction. Reference numeral326denotes a flexible print cable (referred to as an FPC below). The magnet313pis positioned by being pressed into the magnet base311; the back yoke314pis assembled into the magnet base by sliding it in the optical axial direction; the coil324pis fixed by being pressed into the shift base321; and the yoke325pis assembled into the shift base321by sliding it in the optical axial direction.

Also, the yoke325pincludes a projection325′pformed by half blanking. The projection325′pis spaced from both the magnetic poles of the bipolarized magnet313pat substantially the same interval. Hence, the forces pulling the projection325′pby both the magnetic poles are substantially the same so as to have a well-balanced state. Members321dto321kcan be arranged in the shift base321for positioning the FPC326.329is a fixing plate to fix FPC326.

The FPC326is operatively connected to the shift base321by being assembled into the positioning members321dto321kand fixed by the fixing plate329. The coil324pand the yoke325pare fixed to the shift base321while the magnet313pand the back yoke314pare fixed to the magnet base311. Then, the magnet313p, the back yoke314p, and the yoke325pform a magnetic circuit. When an electric current is passed through the coil324p, the movable unit34is shifted in a direction substantially perpendicular to the polarization boundary of the bipolarized magnet313ptogether with the magnet.

Since the driving device structured in such a manner are provided in the pitch direction and the yaw direction, driving forces can be applied in the pitch and yaw directions substantially perpendicular to each other on a plane perpendicular to the optical axis. That is, the exemplary embodiment has a so-called moving magnet driving device. By a magnetic attraction force generated between the magnet313pand the yoke325p, the yoke325pis attracted toward the magnet313p. That is, by arranging the balls so that the resultant force in the magnetic circuit in the pitch and yaw directions can be applied inside the balls323ato323c, the movable unit34can be urged toward the shift base321.

Between the abutment surfaces of the three balls323ato323c, the metallic plates322ato322c, and the metallic plate312, lubricating oil can be applied so as to reduce the chance of balls323ato323cfrom being easily displaced.

Next, the relationship between the ball323aand the shift base unit32and the movable unit34will be described with reference toFIGS. 6A and 6B. Since the relationship of the balls323band323cthereto is the same, only the ball323awill be described herein.FIG. 6Ais a schematic sectional view of the ball323aat the plane substantially passing the ball center in parallel with the optical axis; andFIG. 6Bis a schematic view of the ball323aand its vicinity viewed from the front lens. Arranging the metallic plate322ain the recess321aprovided in the shift base321forms a space327a. The ball323ais arranged within the space327ashown inFIG. 6Aso as to abut the internal bottom surface322a1of the metallic plate322a. The movement of the ball323ais restricted by four surfaces formed of internal sides322a2and322a3of the metallic plate322aand internal walls321a1and321a2of the shift base321.

The ball323ais displaced in the state abutting the surface322a1of the metallic plate322aand the abutment surface312aof the metallic plate312within the range defined by the surfaces322a2,322a3,321a1, and321a2. The ball323a, the metallic plate322a, the metallic plate312, the surfaces322a2,322a3,321a1, and321a2, and the entire moving region of the ball constitute support guiding device configured for moving the movable unit34on the plane perpendicular to the optical axis. Also, the ball323ais clamped between the metallic plate322aand the metallic plate312, and is rolling within the movement restriction range. Since the rolling friction herein is sufficiently smaller than the sliding friction, the ball323acannot slip on the metallic plate322aand the abutment surfaces322a1and312aof the metallic plate312. Hence, the movable unit34moves relative to the shift base unit32while rolling the ball323a. Since the movable unit34and the shift base unit32move relative to the center of the ball323a, the displacement of the ball323arelative to the shift base unit32is the half of that of the movable unit34.

Then, the position detecting device will be described. As mentioned above, the magnet313pcombines position detection with driving. A Hall element328pconverts the magnetic flux density into an electric signal, and is operatively connected to the FPC326adjacent to the image plane in the optical axial direction (e.g., by soldering or other fastening methods as known by one of ordinary skill in the relevant arts). Since the FPC326is fixed so as to cover the surface adjacent to the front lens in the optical axial direction of the coil324pfixed by pressing, the Hall element328pis arranged inside the coil324p. When the movable unit34and the third lens group L3are driven, the change in magnetic flux density of the magnet313pis detected by the Hall element328pso as to output an electrical signal. On the basis of the electric signal from the Hall element328p, a control circuit (below mentioned and numeral37ofFIG. 11) can detect positions of the movable unit34and the third lens group L3.

Since the respective boundaries of the bipolarized magnet in the pitch and yaw directions can be arranged perpendicularly to its detection direction, the position of the movable unit34can be detected biaxial independently. Like in the exemplary embodiment, by one magnet combining position detection with driving, the sensor magnet included in the position detecting device can be eliminated, reducing the thickness of the entire shift unit3in the optical axial direction.

Then, the positional relationship between the light-amount adjustment unit7and the shift unit3will be described with reference again toFIGS. 1 and 5. A space333is surrounded with the lens holder331aof the first shift barrel331, the second shift barrel332, and the connection part331bbetween the first second shift barrels331and332. The length of the space333in the optical axial direction is slightly larger than that of the light-amount adjustment unit7between the press strip701and the ND bottom board707. The light-amount adjustment unit7is adjacent to the bottom of the movable unit34in the pitch moving direction viewed from the front lens.

Then, the assembling method of the light-amount adjustment unit7will be described. The light-amount adjustment unit7is inserted into the space333in a direction perpendicular to the optical axis from the bottom of the shift unit in the pitch direction and is fixed to the shift unit3with a screw708. In such a manner, the light-amount adjustment unit7is inserted into the space333of the shift unit3from the rear, and is fixed to the shift unit3with the screw. By doing so, the performance evaluation of the shift unit3can be easily executed as a single article before the assembling of the light-amount adjustment unit7as well as the assemble operation of the light-amount adjustment unit7is easy.

Then, guiding device of the L-shaped shaft302will be described with reference again toFIGS. 3 and 4. Concave support parts321gand321hare provided in the shift base; and support parts331cand331dprovided in the first shift barrel331support the L-shaped shaft302adjacent to the image plane in the optical axial yaw direction. By the sliding of the L-shaped shaft302relative to the support parts321gand321h, the movable unit34moves in the yaw direction by being suppressed to rotate on the plane perpendicular to the optical axis. The entire support parts321g,321h,331c, and331dconstitute a first guiding device. Support parts321iand321jprovided in the shift base321determine the position of the L-shaped shaft302in the optical axial pitch direction; and concave support parts311aand311bare provided in the magnet base311. By the sliding of the L-shaped shaft302relative to the support parts311aand311b, the movable unit34moves in the pitch direction by being suppressed to rotate on the plane perpendicular to the optical axis. The entire support parts321i,321j,311a, and311bconstitute a second guiding device.

The dimensions of the guiding device will be described with reference toFIG. 7.FIG. 7is a schematic sectional view of the L-shaped shaft302and the guiding device at a section in a direction perpendicular to the axis of the L-shaped shaft302for illustrating the configurations of the L-shaped shaft302and the guiding device in detail. The dimension D is the outer diameter of the L-shaped shaft302; the dimension H1is the open width in the optical axial direction of the concave portion of the support parts311a,311b,321g, and321hso as to be fitted by the L-shaped shaft302; and the dimension H2is the interval in the optical axial direction between the surfaces opposing each other of the support parts311aand311bso as to be fitted by the L-shaped shaft302in the similar way. Since the support parts321iand321jare provided in the shift base321forming the shift base unit32, by the fitting of the length in the optical axial direction of the support parts321iand321j, the position in the optical axial direction of the L-shaped shaft302is determined.

On the other hand, the space between the surfaces of the support parts311a,311b,331c, and331dsupporting the L-shaped shaft302in the optical axial direction and the L-shaped shaft302has slight clearances at this time. The support parts311aand311band the support parts331cand331dcan be arranged adjacent to the movable unit34, and the position in the optical axial direction of the movable unit34is determined with the shift base unit32therebetween. This is because even when variations of tolerance in the optical axial direction are combined, the minimum allowance therefor is required. By such dimensions, the L-shaped shaft302can be smoothly guided in the optical axial direction as well as in the direction perpendicular to the optical axis.

Then, the positional relationship between the L-shaped shaft302and the guiding device viewed in the optical axial direction will be described with reference toFIG. 8.FIG. 8is a drawing of the shift unit3and the light-amount adjustment unit7viewed from the front lens. InFIG. 8, dotted lines show the L-shaped shaft302, the guiding device, and the support guiding device of the movable unit; oblique lines A and B represent regions occupied by the support guiding device of the movable member in the plane perpendicular to the optical axis; and some shapes are omitted. As illustrated inFIG. 8, the support guiding device of the movable member can be arranged in spaces in the pitch direction between the support parts321g,321h,331c, and331dviewed from the optical axial direction; the support guiding device B of the movable member can be arranged in spaces in the yaw direction between the support parts321i,321j,311a, and311b; thereby elongating the fitting length to the utmost. By increasing the fitting length in such a manner, the distortion angle of the L-shaped shaft302in the fitting clearances can be reduced to the utmost so as to guide the movable unit34much more precisely in the pitch and the yaw directions.

In order to elongate the fitting length without increasing the diameter of the shift unit3, according to the embodiment, a space sufficient for the movement of the L-shaped shaft302is secured in the support guiding device of the movable member in the optical axial direction. Therefore, as illustrated inFIG. 8viewed from the optical axial direction, the support guiding device A and B of the movable member and the L-shaped shaft302are partially overlapped with each other in the pitch and the yaw directions. Furthermore, according to the exemplary embodiment, since the light-amount adjustment unit7is arranged adjacent to the bottom side of the movable unit34in the pitch movement direction, moving the L-shaped shaft302in the yaw direction is effective in reducing the diameter of the lens barrel.

Then, the movement direction of the L-shaped shaft302will be described in detail with reference toFIGS. 9A and 9B.FIGS. 9A and 9Bare schematic views for simply illustrating the relationship between the movement of the L-shaped shaft302and the movable unit34/the shift base unit32by showing the L-shaped shaft302and the support parts311a,311b,321g, and321h;FIG. 9Ais a schematic view when the movable unit34moves in the pitch direction; andFIG. 9Bis a schematic view when the L-shaped shaft302and the movable unit34move in the yaw direction. InFIGS. 9A and 9B, not moving members are shown in oblique lines. When the movable unit34moves in the pitch direction, the L-shaped shaft302only guides the movement. When the movable unit34moves in the yaw direction, the L-shaped shaft302, however, moves in the yaw direction together with the movable unit34.

According to the exemplary embodiment, the light-amount adjustment unit7arranged adjacent to the shift unit3is arranged adjacent to the bottom side of the movable unit34in the pitch movement direction. Hence, the L-shaped shaft302is moved in the yaw direction in that the light-amount adjustment unit7does not exist. If the L-shaped shaft302is assumed to move in the pitch direction, the adjacent light-amount adjustment unit7can be displaced outside the optical axis by the movement of the L-shaped shaft302, increasing the diameter of the lens barrel. According to the embodiment, when the movable unit34moves in the pitch direction, it can move independently of the weight of the L-shaped shaft302, the driving device for driving the movable unit34does not consume additional power, contributing to energy saving.

As described above, according to exemplary embodiment, the diameter of the shift unit3is not increased, miniaturizing the optical apparatus. The exemplary embodiment described above has exemplified the moving magnet actuator; alternatively, a moving coil actuator can be applied. Also, according to the exemplary embodiment, the two-divided movable unit has been described; however, at least one exemplary embodiment is not limited to this. According to the exemplary embodiment, the L-shaped shaft302has been described as the rotation restricting device configured for restricting the movable unit from rotating about the optical axis; however, the invention is not limited to this, so that the rotation restricting device can be used, such as a plate having guide grooves shown inFIG. 10and a pitch shaft/a yaw shaft operating independently in the pitch and the yaw directions, respectively. The support guiding device configured to the movable member can also be a guiding device including a pin radially fixed to a movable member or a fixed member and a long groove for the restriction in the optical axial direction. According to the exemplary embodiment, the mechanism in that the correction lens is moved perpendicularly to the optical axis has been described; the correction lens can be moved roughly perpendicularly. That is, the correction lens can be obviously rotated perpendicularly to the optical axis roughly to the extent not largely affecting the optical performance.

Second Exemplary Embodiment

A second exemplary embodiment describes a camera with a lens barrel, which can have the image correction/reduction system according to the first exemplary embodiment.

FIG. 11is a block diagram of an electric circuit of the camera. Referring toFIG. 11, a zoom motor33is a drive power source of the second lens group L2; a voice coil motor with a coil34is a drive power source of the fourth lens group L4; a diaphragm motor35is a drive power source of the light-amount adjustment unit7, using a stepping motor, a photo-interrupter205is a zoom reset switch for detecting the reference position of the second lens group L2, which detects the movement of the second lens group L2in the optical axial direction (the relative position to the reference position) by continuously counting the number of pulse signals entering the zoom motor33after detecting the reference position of the second lens group L2; reference numeral36denotes a diaphragm encoder; a control circuit37includes a CPU for controlling the camera; and a camera signal processing circuit38performs signal processing, such as predetermined amplification and gamma correction, on the output from the image-pickup element601. The contrast signal of the picture signal subjected to such processing is fed to an AE gate39and an AF gate40. The AE gate39and the AF gate40establish optimum signal sorting ranges for the exposure control and for the focusing in picture signals of the entire picture planes, respectively. The size of the gate can be variable or a plurality of gates can be provided.

An AF signal processing circuit41processing an AF signal for AF (auto-focusing) produces one or a plurality of outputs related to the high-frequency component of the picture signal; reference numeral42denotes a zoom switch; and numeral43denotes a zoom tracking memory. The zoom tracking memory43can store the positional information of the focusing lens (the fourth lens group L4) during variation corresponding to the object distance and the position of the variator (the second lens group L2). A memory in the control circuit37can also be used as the zoom tracking memory. Upon operating the zoom switch42, the control circuit37controls driving the zoom motor33and the focus motor34so that the predetermined positional relationship is maintained between the second lens group L2and the fourth lens group L4on the basis of the information of the zoom tracking memory43. During auto-focusing, the control circuit37controls driving the voice coil motor so that the output of the AF signal processing circuit41shows a peak. Also, the control circuit37controls driving the diaphragm motor35using the average output of the Y signal passing through the AE gate39as a reference so that the output of the diaphragm encoder35corresponds to the reference. Deflection sensors51and52detect the angular change of a vibrating gyroscope in the pitch and the yaw directions, respectively. the control circuit37drives the third lens group L3by controlling the electrification to the blur reduction coil324on the basis of the outputs from the deflection sensors51and52and the signal from the hall sensor328.

According to the exemplary embodiment described above, an image-pickup apparatus is exemplified in which a lens barrel is provided integrally with a camera body. However, the lens barrel according to at least one exemplary embodiment can also be applied to an interchangeable lens device in that the lens barrel is detachably provided in the camera body, a photographic camera for 35 mm film, a digital still camera, and a video camera. Moreover, it can also be applied to an observation optical apparatus such as a binocular glass, which can have a vibration isolating function.

This application claims the benefit of Japanese Application No. 2005-178819 filed Jun. 20, 2005, which is hereby incorporated by reference herein in its entirety.