Patent Publication Number: US-9411125-B2

Title: Lens barrel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of U.S. patent application Ser. No. 14/447,843, now abandoned, which is a continuation application of International Application PCT/JP2013/000589, with an international filing date of Feb. 1, 2013 which claims priority to Japanese Patent Application No. 2012-021394 filed on Feb. 2, 2012 and Japanese Patent Application No. 2012-021396 filed on Feb. 2, 2012. The entire disclosures of International Application PCT/JP2013/000589, Japanese Patent Application No. 2012-021394, and Japanese Patent Application No. 2012-021396 are hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The technology disclosed herein relates to a lens barrel equipped with an optical system. 
     2. Background Information 
     A lens barrel having a second group lens capable of retraction in relation to a first group lens has been proposed in the past (see Japanese Laid-Open Patent Application 2011-150132). Here, a second group lens supporting frame (corresponds to a retracting lens frame) that supports the second group lens is able to retract with respect to a support member that supports the first group lens. More specifically, a pressed protrusion of the second group lens supporting frame is pressed by a detachment control protrusion formed on an imaging element holder. Consequently, the orientation of the second group lens supporting frame changes from an imaging enabled orientation to a retracted orientation. 
     In prior art, the orientation of the second group lens supporting frame was changed from an imaging enabled orientation to a retracted orientation by pressing on the second group lens supporting frame with the detachment control protrusion of the imaging element holder. In this case, the detachment control protrusion has to be formed so that it extends in the optical axis direction on the imaging element holder. Therefore, there is the risk that the imaging element holder will end up being larger. 
     One possible way to solve this problem is to provide a cam mechanism between the second group lens supporting frame and a frame body disposed around the outer periphery of the second group lens supporting frame. In this technology, for example, the second group lens supporting frame can be changed from an imaging enabled orientation to a retracted orientation by forming a cam groove in the frame body, and guiding the above-mentioned pressed protrusion in this cam groove of the frame body. In this case, however, there is the risk that forming the cam groove will make the frame body thicker in the radial direction and make the lens barrel larger. Also, if the cam groove is formed without increasing the thickness in the radial direction, there is the risk of a decrease in strength. 
     The technology disclosed herein was conceived in light of the above problem, and it is an object of the present technology is to reduce the size of a lens barrel without sacrificing the strength of the lens barrel. 
     SUMMARY 
     The lens barrel disclosed herein comprises a first lens including a first optical axis, a second lens including a second optical axis, a first frame body, a second frame body, and a retracting lens frame. The second frame body is configured to move in the first optical axis direction with respect to the first frame body. The retracting lens frame is configured to support the second lens. The retracting lens frame is supported by the second frame body. The retracting lens frame is configured to move so that a position of the second optical axis changes from a position on the first optical axis to a position that is outside the first optical axis during the transition period between the imaging enabled state and the housed state. The first frame body includes a cylindrical part. A contact portion is formed on the inner peripheral part of the cylindrical part. The contact portion includes at least one side wall. The at least one side wall is configured to stand toward an inside of the cylindrical part. The retracting lens frame includes a protrusion. The protrusion is configured to engage with the contact portion and be guided by the contact portion when the retracting lens frame moves around a retraction shaft. The thickness of a region constituting the side wall of the contact portion is increased over the thickness of the other region toward the inside of the cylindrical part. 
     The technology disclosed herein provides a lens barrel that can be made smaller without sacrificing strength. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the attached drawings, which form a part of this original disclosure: 
         FIG. 1  is an oblique view of a digital camera; 
         FIG. 2  is an oblique view of a lens barrel; 
         FIG. 3  is an exploded oblique view of a lens barrel; 
         FIG. 4  is an oblique view of a stationary frame; 
         FIG. 5  is an oblique view of a first rectilinear frame; 
         FIG. 6  is an oblique view of a first rotary frame; 
         FIG. 7  is an oblique view of a second rectilinear frame; 
         FIG. 8  is an oblique view of a second rotary frame: 
         FIG. 9A  is an oblique view of a third rectilinear frame; 
         FIG. 9B  is an oblique view of a third rectilinear frame: 
         FIG. 10  is a simplified view of when the second rectilinear frame, the second rotary frame, and the third rectilinear frame have been assembled; 
         FIG. 11  is an oblique view of a first lens group frame; 
         FIG. 12A  is an oblique view of a second lens group frame; 
         FIG. 12B  is a view of the second lens group frame from the front; 
         FIG. 12C  is an oblique view of the relation between the second lens group frame and the sheet member; 
         FIG. 13A  is an oblique view of a shutter frame; 
         FIG. 13B  is a diagram of the shutter frame as seen from the subject side: 
         FIG. 14A  is an oblique view of the shutter frame, an OIS frame, and the retracting lens frame; 
         FIG. 14B  is a cross section of the shutter frame, the OIS frame, the retracting lens frame, and the second lens group frame; 
         FIG. 15A  is an oblique view of the OIS frame; 
         FIG. 15B  is a detail cross section of the state when the retracting lens frame has been engaged with an anti-rotation portion of the OIS frame; 
         FIG. 16A  is a cross section of the state when a rotary spring biases the retracting lens frame to the OIS frame; 
         FIG. 16B  is a detail cross section of the contact state between a retraction shaft and a contact face; 
         FIG. 17A  is an oblique view of the relation between the second lens group frame and the retracting lens frame (imaging enabled state); 
         FIG. 17B  is an oblique view of the relation between the second lens group frame and the retracting lens frame (retracted state); 
         FIG. 18A  is a diagram of the relation between the shutter frame and the retracting lens frame (imaging enabled state); 
         FIG. 18B  is a cross section of the relation between the shutter frame and the retracting lens frame (imaging enabled state); 
         FIG. 18C  is a diagram of the relation between the shutter frame and the retracting lens frame (retracted state); 
         FIG. 19  is a diagram of the retracting lens frame as seen from an imaging element side; 
         FIG. 20  is a simplified cross section of the lens barrel (retracted state); 
         FIG. 21  is a simplified cross section of the lens barrel (wide angle state); 
         FIG. 22  is a simplified cross section of the lens barrel (telephoto state); 
         FIG. 23A  is a side view of the rotary spring pertaining to another embodiment; 
         FIG. 23B  is a side view of the state when the rotary spring pertaining to another embodiment has been mounted to the retracting lens frame; and 
         FIG. 24  is a detail cross section of the state when the retracting lens frame has been engaged with the anti-rotation portion of the OIS frame. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Selected embodiments of the present technology will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present technology are provided for illustration only and not for the purpose of limiting the technology as defined by the appended claims and their equivalents. 
     Next, an embodiment of the present technology will be described through reference to the drawings. In the description of the drawings that follows, portions that are the same or similar will be numbered the same or similarly. The drawings are merely schematic representations, however, and the proportions of the various dimensions and so forth may be different from those in actuality. Therefore, the specific dimensions and so forth should be determined by referring to the following description. Also, the mutual dimensional relations and proportions among the drawings may, of course, vary in some portions. 
     In the following embodiment, a digital camera will be described as an example of an imaging device. In the following description, assuming that the digital camera is in its landscape orientation, the subject side will be referred to as the “front,” the opposite side from the subject as the “rear,” the vertically upper side as “upper,” the vertically lower side as “lower,” the right side when facing the subject as “right,” and the left side when facing the subject as “left.” “Landscape orientation” is a kind of orientation of a digital camera, and when an image is captured in landscape orientation, the long-side direction of a rectangular image that is wider than it is tall substantially coincides with the horizontal direction within the image. 
     Configuration of Digital Camera  1   
     The configuration of the digital camera  1  will now be described through reference to the drawings.  FIG. 1  is an oblique view of the digital camera  1 .  FIG. 2  is an oblique view of a lens barrel  20 . 
     As shown in  FIG. 1 , the digital camera  1  comprises a housing  10  and the lens barrel  20 . 
     The housing  10  is made up of a front panel  11 , a rear panel  12 , and a side panel  13 . An opening  10 S is formed in the front panel  11 . 
     The lens barrel  20  comprises a three-stage retractable zoom mechanism. The lens barrel  20  is housed in the housing  10  when not being used for imaging, and is deployed forward from the opening  10 S during imaging. More specifically, as shown in  FIG. 2 , the lens barrel  20  has a first movable lens barrel portion  21 , a second movable lens barrel portion  22 , a third movable lens barrel portion  23 , and a stationary lens barrel  24 . 
     The first movable lens barrel portion  21  can be deployed with respect to the stationary lens barrel  24 . The second movable lens barrel portion  22  can be deployed with respect to the first movable lens barrel  21 . The third movable lens barrel portion  23  can be deployed with respect to the second movable lens barrel  22 . The stationary lens barrel  24  is fixed inside the housing  10 . When the lens barrel  20  is deployed, the third movable lens barrel portion  23  is located the farthest forward of the first to third movable lens barrel portions  21  to  23 . 
     Detailed Configuration of Lens Barrel  20   
     Next, the detailed configuration of the lens barrel  20  will be described through reference to the drawings.  FIG. 3  is an exploded oblique view of the lens barrel  20 . 
     The first to third movable lens barrel portions  21  to  23  of the lens barrel  20  are deployed from the stationary lens barrel  24  along the optical axis AX of the optical system. The optical system includes first to fourth lens groups L 1  to L 4 . In the following description, a direction parallel to the optical axis AX shall be referred to as the “optical axis direction.” a direction perpendicular to the optical axis direction as the “radial direction,” and a direction that goes in a circle around the optical axis AX as the “peripheral direction.” The optical axis AX substantially coincides with the axis of the frames that make up the lens barrel  20 . 
     In this embodiment, the term “rectilinear frame” means a frame that moves in the optical axis direction, without rotating in the peripheral direction. A “rotary frame” means a frame that rotates in the peripheral direction. The term “rotary frame” encompasses the meaning of both a frame that moves in the optical axis direction and a frame that does not move in the optical axis direction. The term “rectilinear groove” means a groove provided along the optical axis direction. A “rectilinear groove” is provided to both rectilinear and rotary frames. 
     The term “rectilinear” means moving in the optical axis direction, and not rotating in the peripheral direction. The term “rotary” means rotating in the peripheral direction. The term “rotary” is used in the meaning of both moving in the optical axis direction and not moving in the optical axis direction. The term “move” is a concept that also encompasses moving in the optical axis direction while rotating in the peripheral direction. 
     The term “bayonet” or “bayonet mechanism” means a mechanism in which frames having a “bayonet protrusion” and a “bayonet groove” provided in the peripheral direction are rotatably engaged, and a mechanism in which these frames are integrally engaged in the optical axis direction. 
     1. First Movable Lens Barrel Component  21   
     The first movable lens barrel portion  21  has a first rectilinear frame  110 , a first rotary frame  210 , and a first cosmetic frame  301 . The first rectilinear frame  110  is a cylindrical plastic member disposed on the inside in the radial direction of a stationary frame  100  (discussed below). The first rotary frame  210  is a cylindrical plastic member disposed on the inside in the radial direction of the first rectilinear frame  110 . The first cosmetic frame  301  is a cylindrical sheet metal member that covers the outer periphery of the first rectilinear frame  110 . 
     2. Second Movable Lens Barrel Component  22   
     The second movable lens barrel portion  22  has a second rectilinear frame  120 , a second rotary frame  220 , a third rectilinear frame  130 , a second lens group frame  320 , a second lens group L 2 , a third lens group frame  330 , a third lens group L 3 , a shutter frame  335 , and a second cosmetic frame  302 . 
     The second rectilinear frame  120  is a cylindrical plastic member disposed on the inside in the radial direction of the first rotary frame  210 . The second rotary frame  220  is a cylindrical plastic member disposed on the inside in the radial direction of the second rectilinear frame  120 . 
     The third rectilinear frame  130  is a cylindrical plastic member disposed on the inside in the radial direction of the second rotary frame  220 . The second lens group frame  320  is disposed on the inside in the radial direction of the third rectilinear frame  130 , and supports the second lens group L 2 . The third lens group frame  330  is housed in the shutter frame  335 , and supports the third lens group L 3  used for image blur correction. The third lens group frame  330  is supported pivotably in the radial direction by the shutter frame  335 , and constitutes an image blur correction mechanism along with the third lens group L 3 . 
     The shutter frame  335  is disposed on the inside in the radial direction of the third rectilinear frame  130 , and has a built-in shutter mechanism. The shutter frame  335  supports the third lens group frame  330  pivotably in the radial direction. A control-use flexible wire  335   a  is connected to the shutter frame  335 . 
     The control-use flexible wire  335   a  is disposed along the inner peripheral face of the stationary frame  100 , and is connected to a control device (not shown). The control-use flexible wire  335   a  transmits drive power and control signals to the shutter mechanism and the image blur correction mechanism (discussed below). The second cosmetic frame  302  is a cylindrical sheet metal member that covers the outer periphery of the second rectilinear frame  120 . 
     3. Third Movable Lens Barrel Component  23   
     The third movable lens barrel portion  23  has a first lens group frame  310 , a first lens group L 1 , and a third cosmetic frame  303 . 
     The first lens group frame  310  is disposed between the second rectilinear frame  120  and the second rotary frame  220 . The first lens group frame  310  supports the first lens group L 1 , which is used to bring light into the lens barrel  20 . The third cosmetic frame  303  is a cylindrical sheet metal member that covers the outer periphery of the first lens group frame  310 . 
     4. Stationary Lens Barrel  24   
     The stationary lens barrel  24  has the stationary frame  100 , a fourth lens group frame  340 , a fourth lens group L 4 , a zoom motor  241 , a zoom gear  242 , a focus motor  243 , a master flange  244 , an imaging element  245 , and an imaging element flexible wire  245   a.    
     The stationary frame  100  is a cylindrical plastic member disposed on the outside in the radial direction of the first rotary frame  210  and the first rectilinear frame  110 . The fourth lens group frame  340  is attached to the master flange  244 , and is driven in the optical axis direction by the focus motor  243 . The fourth lens group frame  340  supports the fourth lens group L 4 , which is used for focal adjustment. 
     The zoom motor  241  is a drive source that is used to deploy the first to third movable lens barrel portions  21  to  23 , and is attached to the side face of the stationary frame  100 . The zoom gear  242  transmits the drive force of the zoom motor  241  to the first rotary frame  210 . The front end of the zoom gear  242  is supported by the stationary frame  100 , and the rear end of the zoom gear  242  is supported by the master flange  244 . The focus motor  243  is a drive source that is used to drive the fourth lens group frame  340  in the optical axis direction, and is attached to the master flange  244 . The master flange  244  is a flat plastic member that covers the rear of the stationary frame  100 . The imaging element  245  is fitted into the center of the master flange  244 . In a state in which the imaging element flexible wire  245   a  and the imaging element  245  have been electrically connected, the imaging element flexible wire  245   a  is affixed to the rear face of the master flange  244 . The imaging element flexible wire  245   a  is connected to a control device (not shown), and transmits signals from the imaging element  245 . 
     Configuration of Frames 
     The frames that make up the lens barrel  20  will now be described through reference to the drawings. More specifically, the configurations of the stationary frame  100 , the first rectilinear frame  110 , the first rotary frame  210 , the second rectilinear frame  120 , the second rotary frame  220 , the third rectilinear frame  130 , the first lens group frame  310 , the second lens group frame  320 , the third lens group frame  330 , and the shutter frame  335  will be described in order, after which we will describe how the frames are engaged with each other. 
     1. Configuration of Stationary Frame  100   
       FIG. 4  is an oblique view of the stationary frame  100 . The stationary frame  100  has a stationary frame main body  101  and a zoom gear support  102 . 
     The stationary frame main body  101  is formed in a cylindrical shape, and has an inner peripheral face  100 S and an outer peripheral face  100 T. 
     The zoom gear support  102  is provided so as to protrude from the outer peripheral face  100 T. The zoom gear support  102  rotatably supports the front end of the zoom gear  242 . In this embodiment, the zoom gear support  102  is covered by the front panel  11 , so it is not exposed on the outside of the housing  10  (see  FIG. 1 ). The teeth of the zoom gear  242  protrude on the inside of the stationary frame main body  101 . 
     The stationary frame  100  has five rectilinear grooves a 1  and three cam grooves b 1 . In  FIG. 4 , however, only three rectilinear grooves a 1  and two cam grooves b 1  are shown. 
     The five rectilinear grooves a 1  are formed in the inner peripheral face  100 S in the optical axis direction, and are suitably spaced apart in the peripheral direction. 
     The three cam grooves b 1  are formed in the inner peripheral face  100 S so as to intersect the optical axis direction. 
     2. Configuration of First Rectilinear Frame  110   
       FIG. 5  is an oblique view of the first rectilinear frame  110 . The first rectilinear frame  110  has a first rectilinear frame main body  111 , five rectilinear protrusions A 1 , three rectilinear grooves a 2 , a bayonet groove e 1 , and a bayonet protrusion E 0 . 
     The rectilinear frame main body  111  is formed in a cylindrical shape, and has an inner peripheral face  110 S and an outer peripheral face  110 T. 
     The five rectilinear protrusions A 1  are provided at the rear end of the outer peripheral face  110 T. The five rectilinear protrusions A 1  are engaged with the five rectilinear grooves a 1  of the stationary frame  100 . 
     The three rectilinear grooves a 2  are formed in the inner peripheral face  110 S in the optical axis direction. 
     The bayonet groove e 1  is formed in an arc shape in the peripheral direction at the rear end of the inner peripheral face  110 S. The bayonet groove e 1  intersects the three rectilinear grooves a 2 . 
     The bayonet protrusion E 0  is disposed at the front end of the inner peripheral face  110 S. The bayonet protrusion E 0  is formed in an arc shape in the peripheral direction. In this embodiment, a plurality of bayonet protrusions E 0  are provided in the peripheral direction. 
     3. Configuration of First Rotary Frame  210   
       FIG. 6  is an oblique view of the first rotary frame  210 . The first rotary frame  210  has a first rotary frame main body  211  and a gear portion  212 . 
     The first rotary frame main body  211  is formed in a cylindrical shape, and has an inner peripheral face  210 S and an outer peripheral face  210 T. 
     The gear portion  212  is provided to the rear end of the outer peripheral face  210 T, and is formed in the peripheral direction. When the gear portion  212  meshes with the zoom gear  242 , the first rotary frame  210  is rotated in the peripheral direction by the drive force of the zoom motor  241 . Although not depicted, the gear portion  212  is disposed further to the rear than the rectilinear protrusions A 1  of the first rectilinear frame  110 . 
     The first rotary frame  210  has three cam followers B 1 , three bayonet protrusions E 1 , three cam grooves b 2 , a bayonet groove e 0 , and three rectilinear grooves a 3 . In  FIG. 6 , however, only one of the rectilinear grooves a 3  is shown. 
     The three cam followers B 1  are provided to the rear end of the outer peripheral face  210 T. Two of the three cam followers B 1  are disposed at the both ends of the gear portion  212 . The three cam followers B 1  engages with the cam grooves b 1  of the stationary frame  100 . 
     The bayonet protrusions E 1  are formed in the peripheral direction at the rear end of the outer peripheral face  210 T. The bayonet protrusions E 1  are disposed in front of the gear portion  212 . The bayonet protrusions E 1  engages with the bayonet groove e 1  of the first rectilinear frame  110 . In this embodiment, the bayonet protrusions E 1  and the bayonet groove e 1  constitute a bayonet mechanism for rotatably engaging the first rotary frame  210  with the first rectilinear frame  110 , and integrally engaging these in the optical axis direction. 
     The three cam grooves b 2  pass through the first rotary frame main body  211  from the inner peripheral face  210 S to the outer peripheral face  210 T. 
     The bayonet groove e 0  is formed at the front end of the outer peripheral face  210 T. The bayonet groove e 0  is formed in an arc shape in the peripheral direction. The bayonet groove e 0  intersects the three cam grooves b 2 . The bayonet protrusion E 0  engages with the bayonet groove e 0 . 
     The three rectilinear grooves a 3  are formed in the inner peripheral face  210 S in the optical axis direction. Two of the three rectilinear grooves a 3  are close together, and are formed away from the other one in a range from 120° to 180°. 
     4. Configuration of Second Rectilinear Frame  120   
       FIG. 7  is an oblique view of the second rectilinear frame  120 . The second rectilinear frame  120  has a second rectilinear frame main body  121  and two latching portions  122 . 
     The second rectilinear frame main body  121  is formed in a cylindrical shape, and has an inner peripheral face  120 S and an outer peripheral face  120 T. 
     The two latching portions  122  are provided on the rear end face of the second rectilinear frame main body  121 , and protrude toward the rear. The two latching portions  122  are formed at substantially symmetrical positions around the optical axis AX (see  FIG. 3 ), that is, at positions that are separated by 120° to 180°. As will be discussed below, when the two latching portions  122  are latched to the third rectilinear frame  130 , the relative rotation of the third rectilinear frame  130  with respect to the second rectilinear frame  120  is prevent. In this embodiment, one of the two latching portions  122  is formed longer in the peripheral direction than the other one. 
     The second rectilinear frame  120  has three rectilinear cam followers AB 2 , three rectilinear grooves a 4 , and a bayonet groove e 2 . 
     The three rectilinear cam followers AB 2  are provided at the rear end of the outer peripheral face  120 T, and are disposed at a substantially constant pitch in the peripheral direction. The three rectilinear cam followers AB 2  engages with the three cam grooves b 2  of the first rotary frame  210 . Also, the three rectilinear cam followers AB 2  pass through the three cam grooves b 2  and engages with the three rectilinear grooves a 2  of the first rectilinear frame  110 . 
     The three rectilinear grooves a 4  are formed in the inner peripheral face  120 S in the optical axis direction. The three rectilinear grooves a 4  are disposed at a substantially constant pitch in the peripheral direction. 
     The bayonet groove e 2  is formed at the rear end of the inner peripheral face  120 S in the peripheral direction. The bayonet groove e 2  intersects the three rectilinear grooves a 4 . 
     5. Configuration of Second Rotary Frame  220   
       FIG. 8  is an oblique view of the second rotary frame  220 . The second rotary frame  220  has a second rotary frame main body  221 , three rectilinear protrusions A 3 , three bayonet protrusions E 2 , two bayonet grooves e 3 , three cam grooves b 3 , three cam grooves b 4 , three cam grooves b 5 , and three cam followers B 6 . In  FIG. 8 , however, only two each of the cam grooves b 3 , the cam grooves b 4 , and the cam grooves b 5  are shown. 
     The second rotary frame main body  221  is formed in a cylindrical shape, and has an inner peripheral face  220 S and an outer peripheral face  220 T. 
     The three rectilinear protrusions A 3  are provided at the rear end of the outer peripheral face  220 T, two of the three rectilinear protrusions A 3  are close together in the peripheral direction, and the other one is separated by about 120° or more from the two rectilinear protrusions A 3  that are close together. The three rectilinear protrusions A 3  engages with the three rectilinear grooves a 3  of the first rotary frame  210 . 
     The three bayonet protrusions E 2  are formed in the peripheral direction at the rear end of the outer peripheral face  220 T. The three bayonet protrusions E 2  are disposed in front of the three rectilinear protrusions A 3 . The bayonet protrusions E 2  engages with the bayonet groove e 2  of the second rectilinear frame  120 . In this embodiment, the bayonet protrusions E 2  and the bayonet groove e 2  constitute a bayonet mechanism for engaging the second rotary frame  220  rotatably with the second rectilinear frame  120  and integrally in the optical axis direction. 
     The shape of the bayonet grooves e 3  in a cross section including the optical axis is a trapezoidal shape in which the side on the outside in the radial direction is shorter, and the side on the inside in the radial direction is longer, and the bayonet grooves e 3  are formed in the approximate center of the inner peripheral face  220 S in the peripheral direction. The two bayonet grooves e 3  are formed parallel to each other. The two bayonet grooves e 3  intersect with the cam grooves b 4  and the cam grooves b 5 . The radial direction depth of the two bayonet grooves e 3  is shallower than the radial direction depth of the cam grooves b 4  and the cam grooves b 5 . 
     The three cam grooves b 3  are formed in the outer peripheral face  220 T so as to intersect with the optical axis direction, and are disposed at a substantially constant pitch in the peripheral direction. 
     The cam grooves b 4  and the cam grooves b 5  are formed in the inner peripheral face  220 S. The cam grooves b 4  and the cam grooves b 5  intersect each other. The radial depth of the cam grooves b 4  is substantially the same as the cam grooves b 5 . 
     The three cam followers B 6  are provided to the front end of the outer peripheral face  220 T, and are disposed at a substantially constant pitch in the peripheral direction. In  FIG. 8 , however, only two of the cam followers B 6  are shown. 
     6. Configuration of Third Rectilinear Frame  130   
       FIGS. 9A and 9B  are oblique views of the third rectilinear frame  130 . The third rectilinear frame  130  has a third rectilinear frame main body  131 , a flange  132 , and two latching recesses  133 . 
     The third rectilinear frame main body  131  is formed in a cylindrical shape, and has an inner peripheral face  130 S and an outer peripheral face  130 T. 
     The flange  132  is formed in an annular shape, and is provided on the rear end of the outer peripheral face  130 T. 
     The two latching recesses  133  are cut-outs formed in the outer edge of the flange  132 . The two latching recesses  133  are formed in substantially symmetrical positions around the optical axis AX (see  FIG. 3 ), that is, at positions separated by 120° to 180°.  FIG. 10  is a schematic diagram in which the second rectilinear frame  120 , the second rotary frame  220 , and the third rectilinear frame  130  have been put together. As shown in  FIG. 10 , when the two latching portions  122  of the second rectilinear frame  120  are latched to the two latching recesses  133  of the third rectilinear frame  130 , relative rotation of the third rectilinear frame  130  with respect to the second rectilinear frame  120  is prevented. One of the two latching recesses  133  is formed longer in the peripheral direction than the other one, corresponding to the fact that one of the two latching portions  122  is formed longer in the peripheral direction than the other one. This increases the strength of the two latching recesses  133 . 
     The third rectilinear frame  130  has six bayonet protrusions E 3 , three rectilinear grooves a 5 , and three rectilinear grooves a 6 . In  FIG. 9A , however, only two of the bayonet protrusions E 3  are shown, and in  FIG. 9B , only four of the bayonet protrusions E 3  are shown. 
     The shape of the six bayonet protrusions E 3  in a cross section including the optical axis is a trapezoidal shape in which the side on the outside in the radial direction is shorter, and the side on the inside in the radial direction is longer. Also, the bayonet protrusions E 3  are formed in the peripheral direction in the approximate center of the outer peripheral face  130 T. Two of the bayonet protrusions E 3  are formed parallel to each other at the same position in the peripheral direction. These two bayonet protrusions E 3  form a set, and these sets are disposed at three places at a substantially constant pitch in the peripheral direction. In other words, three sets of the bayonet protrusions E 3 , that is, the six bayonet protrusions E 3 , are disposed on the third rectilinear frame  130 . The six bayonet protrusions E 3  engages with the two bayonet grooves e 3  of the second rotary frame  220 . In this embodiment, the bayonet protrusions E 3  and the bayonet grooves e 3  constitute a bayonet mechanism for rotatably engaging the third rectilinear frame  130  with the second rotary frame  220 , and integrally engaging them in the optical axis direction. 
     The three rectilinear grooves a 5  pass through the third rectilinear frame main body  131  from the inner peripheral face  130 S to the outer peripheral face  130 T. The three rectilinear grooves a 5  extend in the optical axis direction, and are disposed at a substantially constant pitch in the peripheral direction. 
     The three rectilinear grooves a 6  pass through the third rectilinear frame main body  131  from the inner peripheral face  130 S to the outer peripheral face  130 T. The three rectilinear grooves a 6  extend in the optical axis direction, and are disposed at a substantially constant pitch in the peripheral direction. 
     In this embodiment, the three rectilinear grooves a 5  and the three rectilinear grooves a 6  are disposed alternately in the peripheral direction. 
     As shown in  FIG. 9A , the third rectilinear frame  130  further has a guide groove a 7  (an example of a first cam portion) formed in the inner peripheral face of the third rectilinear frame main body  131 , and a reinforcing portion  130 H (shaded part) formed near the guide groove a 7 . 
     The guide groove a 7  guides a driven portion  411  (see  FIG. 14A ; discussed below) as a cam follower. The guide groove a 7  and the driven portion  411  constitute a cam mechanism for moving a retracting lens frame  401 . This cam mechanism changes the orientation of the retracting lens frame  401  when the third rectilinear frame  130  moves relative to the retracting lens frame  401  in the optical axis direction. 
     As shown in  FIG. 9A , the guide groove a 7  has a portion that is inclined to the optical axis direction (inclined part a 71 ) and a portion is that parallel to the optical axis direction (parallel part a 72 ). When the driven portion  411  is guided by this inclined part a 71 , the retracting lens frame  401  rotates around a retraction shaft  501   b . The retracting lens frame  401  transitions between an image blur correction enabled position and a retracted position by rotating around the retraction shaft  501   b . In the retracted position, the driven portion  411  is guided by the parallel part a 72  of the guide groove a 7 , thereby the retracting lens frame  401  stops rotating around the retraction shaft  501   b  at the retracted position. 
     The retracting lens frame  401  is biased by a rotary spring  403  from the retracted position toward the image blur correction enabled position. More precisely, this biasing direction is a direction around the retraction shaft  501   b , a direction perpendicular to the optical axis direction, and a direction in which the retracting lens frame  401  enters its imaging enabled state. Specifically, this biasing direction is a direction in which the optical axis direction of the third lens group L 3  is aligned with the optical axis direction of the other lenses. 
     Therefore, when the guide groove a 7  and the driven portion  411  cause the retracting lens frame  401  to rotate against the biasing force of the rotary spring  403 , the driven portion  411  comes into contact with one side (one side face) of the guide groove a 7 . The guide groove a 7  is formed in the form of a groove. Specifically, the guide groove a 7  is made up of three faces. These three faces constitute a side face a 73  on the front side in the optical axis direction, a side face a 74  on the rear side in the optical axis direction, and a bottom face a 75  that is parallel to the optical axis direction and connects the first two faces. The contact face of the guide groove a 7  that comes into contact with the driven portion  411  is the side face a 73  on the front side in the optical axis direction. Therefore, the retracting lens frame  401  can be rotated as long as the side face a 73  on the front side in the optical axis direction is provided. In this case, the contact face at the position immediately after the completion of retraction is a contact face a 76 . After this, a positioning portion  412  of the retracting lens frame  401  that has been guided by a guide portion  322   a  is supported in a state of being in contact with a support portion  322   b , and the retraction operation is complete. 
     However, because the guide groove a 7  is formed in a grooved shape, that is, constitutes three faces, the position of the driven portion  411  is reliably maintained by the guide groove a 7  even if the camera is dropped, subjected to an impact, etc., so the orientation of the retracting lens frame  401  can be kept stable. For the same reason, the parallel part a 72  is also in a grooved shape, that is, constitutes three faces. Furthermore, even if the rotational load of the retracting lens frame  401  is increased over the rotational force of the rotary spring  403  due to the influence of wear through continuous use or of the adhesion of foreign matter in the guide groove a 7 , the retracting lens frame  401  can still be forcibly rotated. 
     The side face a 73  on the front side in the optical axis direction and the side face a 74  on the rear side in the optical axis direction of the guide groove a 7  are formed in a tapered shape (that is, a sloped face shape) with respect to the direction perpendicular to the optical axis direction, so that there is no undercutting in the sliding direction of the mold during injection molding. The contact face of the driven portion  411  that engages with the guide groove a 7  is also formed in a shape corresponding to the side face a 73  on the front side in the optical axis direction and the side face a 74  on the rear side in the optical axis direction. Specifically, the contact face of the driven portion  411  that engages with the guide groove a 7  is formed in a tapered shape (that is, a sloped face shape) with respect to the direction perpendicular to the retraction shaft  501   b , so that the side face a 73  on the front side in the optical axis direction and the side face a 74  on the rear side in the optical axis direction are substantially parallel to each other. The angle of the sloped face on the side face a 73  on the front side in the optical axis direction is smaller than one on the side face a 74  on the rear side in the optical axis direction. 
     The angle of the sloped face is an angle to the direction perpendicular to the optical axis direction The smaller is the angle of the sloped face to the direction perpendicular to the optical axis direction, the less torque loss is caused by the rotational load of the retracting lens frame  401  generated at the sloped face, and the less it becomes for the driven portion  411  to come loose from the guide groove a 7 . On the other hand, the larger is the angle of the sloped face to the direction perpendicular to the optical axis direction, the easier it becomes to avoid mold undercut during injection molding. Also, the larger is the angle of the sloped face to the direction perpendicular to the optical axis direction, the larger is the angle of the sloped face of the driven portion  411  opposite the sloped face with respect to the direction perpendicular to the retraction shaft  501   b . The larger is the angle of the contact face of the driven portion  411  to the direction perpendicular to the retraction shaft  501   b , the stronger the base of the driven portion  411  can be made. Consequently, damage through continued use, the input of dropping force, impact force, or the like, and so forth can be prevented. 
     In this disclosure, the angle of the sloped face of the side face a 73  on the front side in the optical axis direction with respect to the direction perpendicular to the optical axis direction is small, and the angle of the sloped face of the side face a 74  on the rear side in the optical axis direction with respect to the direction perpendicular to the optical axis direction is large. Also, the sloped face of the driven portion  411  corresponding to these sloped faces is formed so as to be substantially parallel to the faces of the guide groove a 7 . This reduces torque loss through rotational load of the retracting lens frame  401 , and makes it less likely that the driven portion  411  comes loose from the guide groove a 7 . It also prevents damage through continued use, the input of dropping force, impact force, or the like, and so forth. 
     As discussed above, during normal operation, that is, when the camera is not dropped or otherwise subjected to impact, and there is no adhered foreign matter, worn parts, etc., only the side face a 73  on the front side in the optical axis direction is in contact with the driven portion  411 . Accordingly, the above effect can be obtained as long as at least the angle of the side face on the rear side in the optical axis direction with respect to the direction perpendicular to the optical axis is small. 
     Because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , rotation of the retracting lens frame  401  can be started earlier during the transition period between the imaging enabled state and the housed state. If the guide groove a 7  is provided to the stationary portion of the imaging element holder or the like, the retracting lens frame  401  is usually away from the stationary portion in the optical axis direction. Accordingly, during the transition period between the imaging enabled state and the housed state, the guide groove a 7  and the retracting lens frame  401  cannot be instantly engaged, and the rotation of the retracting lens frame  401  cannot be started right away. 
     In contrast, if the guide groove a 7  is provided to the third rectilinear frame  130 , during the transition period between the imaging enabled state and the housed state, the guide groove a 7  and the driven portion  411  always is close enough to engage. Accordingly, if the guide groove a 7  is provided to the third rectilinear frame  130 , the rotation of the retracting lens frame  401  can be started right away during the transition period between the imaging enabled state and the housed state. 
     Also, because the driven portion  411  and the guide groove a 7  are formed in the third rectilinear frame  130 , this improves the rotational precision of the retracting lens frame  401 . For example, if the guide groove a 7  is provided to the stationary portion of the imaging element holder or the like, there is the risk that more parts are in between the driven portion  411  and the guide groove a 7 . The more of these parts there are, the worse is the relative positional accuracy between the driven portion  411  and the guide groove a 7 , and the less accurate is the relative rotation of the retracting lens frame  401  with respect to the retraction shaft  501   b . In contrast, if the guide groove a 7  is provided to the third rectilinear frame  130 , there are relatively few parts in between the driven portion  411  and the guide groove a 7 , so the relative positional accuracy of the retracting lens frame  401  is increased. 
     Also, as discussed above, if the guide groove a 7  is provided to the stationary portion of the imaging element holder or the like, there are more parts in between the driven portion  411  and the guide groove a 7 , so this adversely affects the relative rotational accuracy of the retracting lens frame  401  with respect to the retraction shaft  501   b . Furthermore, if the retracting lens frame  401  is mounted to the OIS frame  400  so as to be rotatable around an axis parallel to the optical axis, there is a further loss of relative rotational accuracy between the driven portion  411  and the guide groove a 7 . To put this another way, if a retraction mechanism is constituted and the OIS frame  400  is mounted to the shutter frame  335  so as to operate in a plane perpendicular to the optical axis (that is, if an image blur correction mechanism is constituted), there is a further loss of relative rotational accuracy between the driven portion  411  and the guide groove a 7 . However, if the guide groove a 7  is provided to the third rectilinear frame  130 , there are relatively few parts in between the driven portion  411  and the guide groove a 7 , so there is better relative rotational accuracy of the retracting lens frame  401  with respect to the retraction shaft  501   b.    
     Also, because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , the guide groove a 7  can be easily constituted by three faces, namely, the side face a 73  on the front side in the optical axis direction, the side face a 74  on the rear side in the optical axis direction, and the bottom face a 75  that is parallel to the optical axis and connects the above-mentioned two faces. 
     On the other hand, if the guide groove a 7  is provided to the stationary portion of the imaging element holder or the like, the guide groove a 7  has to be formed in the stationary portion of the imaging element holder. Here, if an attempt is made to form the three faces constituting the guide groove a 7  in the stationary portion of the imaging element holder, then the stationary portion of the imaging element holder or the like end up being larger. Also, if the guide groove a 7  is formed in a small space in order to avoid making the stationary portion of the imaging element holder larger, the guide groove a 7  is not strong enough. 
     However, if the guide groove a 7  is provided to the third rectilinear frame  130 , since the third rectilinear frame  130  is cylindrical, it is easy to provide the three faces of the guide groove a 7 . Also, in this case there is no need to form the guide groove a 7  in the stationary portion of the imaging element holder or the like, so there is no need to make the stationary portion of the imaging element holder larger. Also, in this case, since the portion where the guide groove a 7  is formed is cylindrical, the strength of the guide groove a 7  can also be improved. 
     Furthermore, because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , positioning can be performed more accurately within the plane perpendicular to the optical axis during retraction. If the guide groove a 7  is provided to the third rectilinear frame  130 , a mechanism for positioning the OIS frame  400  with respect to the third rectilinear frame  130  within the plane perpendicular to the optical axis is formed between it and the third rectilinear frame  130 . Accordingly, there is better positioning accuracy of the retracting lens frame  401  and the OIS frame  400 . 
     The reason why there is a need for a mechanism for positioning the OIS frame  400  with respect to the third rectilinear frame  130  will now be discussed. If the image blur correction mechanism causes the OIS frame  400  to move within the plane perpendicular to the optical axis, the rotational accuracy of the retracting lens frame  401  with respect to the OIS frame  400  decreases. Accordingly, during the retraction operation, the OIS frame  400  has to be stopped with respect to the third rectilinear frame  130 . The reason why the rotational accuracy of the retracting lens frame  401  deteriorates when the OIS frame  400  moves is that the positional relation between the retraction shaft  501   b  installed on the OIS frame  400  and the guide groove a 7  installed on the third rectilinear frame  130  ends up moving. 
     With the positioning mechanism in the example disclosed here, the position where the OIS frame  400  is positioned in the plane perpendicular to the optical axis is the optical axis center. In this case, the distance the OIS frame  400  moves during positioning within the plane perpendicular to the optical axis is relatively short. This allows the positioning mechanism to be smaller. 
     This is not the only option, and the position where the OIS frame  400  is positioned can also be set in the direction toward the guide groove a 7 , offset from the optical axis. In this case, since the retraction shaft  501   b  and the guide groove a 7  move closer together, the speed increasing ratio at which the retracting lens frame  401  rotates can be set higher. Specifically, the ratio of the rotational angle of the lens center of the retracting lens frame  401  to the rotational angle of the driven portion  411 , using the retraction shaft  501   b  as a reference, can be increased. This ensures the rotational angle necessary for retraction of the retracting lens frame  401  even though the guide groove a 7  is relatively short. 
     This is not the only option, and the position where the OIS frame  400  is positioned can be set to the direction away from the guide groove a 7 , offset from the optical axis. In this case, since the retraction shaft  501   b  and the guide groove a 7  move away from each other, the speed increasing ratio at which the retracting lens frame  401  rotates can be set lower. Specifically, the ratio of the rotational angle of the lens center of the retracting lens frame  401  to the rotational angle of the driven portion  411 , using the retraction shaft  501   b  as a reference, can be decreased. This reduces the load exerted on the driven portion  411  during retraction, and prevents wear of the contact face. 
     This is not the only option, and the position where the OIS frame  400  is positioned can be set to the direction in which the retracting lens frame  401  retracts, offset from the optical axis. In this case, the retraction amount, that is, the rotational angle of the retracting lens frame  401  around the retraction shaft  501   b , can be reduced by an amount corresponding to the offset. This ensures the rotational angle necessary for retraction of the retracting lens frame  401  even through the guide groove a 7  is relatively short. In this case, since the pressure angle of the guide groove a 7  can be reduced, the load exerted on the driven portion  411  during retraction can be reduced, and wear of the contact face can be prevented. 
     The reinforcing portion  130 H is formed locally on the third rectilinear frame main body  131 . The reinforcing portion  130 H is formed on the inner peripheral face of the third rectilinear frame main body  131 . More specifically, the reinforcing portion  130 H is formed on the third rectilinear frame main body  131  so as to protrude toward the inside of the third rectilinear frame main body  131 . Specifically, using the outer peripheral face of the third rectilinear frame main body  131  as a reference, the reinforcing portion  130 H is formed so that the thickness of the reinforcing portion  130 H increases toward the inner peripheral side from the thickness of the other portion. The “other portion” referred to here is the portion opposite the third lens support  420  of the retracting lens frame  401  in the housed state, on the inside in the radial direction of the third rectilinear frame main body  131 , or is the portion opposite the actuator installed in the shutter frame  335 . The reinforcing portion  130 H is formed near the guide groove a 7 , such as adjacent to the guide groove a 7 . 
     Also, in a cross section of the reinforcing portion  130 H along a plane that is perpendicular to the optical axis, the inner peripheral face of the reinforcing portion  130 H is substantially formed in an arc shape centered on the retraction shaft  501   b . This allows the thickness to be set without any waste, so the driven portion  411  of the retracting lens frame  401  can be reliably moved in the interior of the guide groove a 7 . 
     The thickness of the reinforcing portion  130 H is determined by the thickness of the guide groove a 7 . Specifically, the thickness of the reinforcing portion  130 H is set so that the depth of the guide groove a 7  (the radial direction dimension of the guide groove a 7 ) fits in the reinforcing portion  130 H. The depth of the guide groove a 7  is determined by the size (height) of the driven portion  411  inserted into the guide groove a 7 . The depth of the guide groove a 7  (the radial direction dimension of the guide groove a 7 ) is set so as to accommodate the height of the driven portion  411  (the radial direction dimension of the driven portion  411 ). 
     The thickness of the third rectilinear frame main body  131  is preferably as thin as possible in order to reduce the outside diameter of the lens barrel  20 . The thickness of the portion opposite the relatively large parts disposed on the inside in the radial direction of the third rectilinear frame main body  131  is preferably reduced. For example, in the housed state, the thickness of the portion opposite the third lens support  420  of the retracting lens frame  401  is preferably reduced. Also, the thickness of the portion opposite the actuators installed on the shutter frame  335  (such as the motor for driving the shutter vanes, the motor for aperture drive, the motor for driving the ND vanes, the coil for correcting image blur, and the magnet for correcting image blur) is preferably reduced. 
     However, the cam mechanism for moving the retracting lens frame  401 , that is, the portion where the guide groove a 7  and the driven portion  411  engage, needs to be strong, so a certain amount of thickness is necessary. If this portion having a certain thickness is formed on the inner peripheral face side of the third rectilinear frame main body  131 , the outside diameter of the third rectilinear frame main body  131  can be kept from becoming larger. Specifically, an increase in the outside diameter of the lens barrel  20  can be suppressed. 
     With the shutter frame  335 , the OIS frame  400 , and the second lens group frame  320  that move in the optical axis direction on the radial direction inside of the third rectilinear frame  130 , the portion opposite the reinforcing portion  130 H is made thinner than the other portion in order to prevent interference. Specifically, this portion is made thinner so that the radial direction dimension becomes smaller. 
     As shown in  FIG. 9B , the third rectilinear frame  130  has two shunting grooves a 9  for restricting movement of the OIS frame  400  with respect to the shutter frame  335  or the third rectilinear frame  130 . The two shunting grooves a 9  are formed in the inner peripheral face  130 S of the third rectilinear frame main body  131 . The two shunting grooves a 9  are formed in the third rectilinear frame main body  131  at a specific distance apart from each other in the peripheral direction on the inner peripheral face  130 S. The two shunting grooves a 9  are disposed at positions of approximately 120°, using the driven portion  411  as a reference, as seen from the optical axis direction. The two shunting grooves a 9  and the guide groove a 7  restrict movement of the OIS frame  400  in the direction perpendicular to the optical axis, with respect to the shutter frame  335  or the third rectilinear frame  130 . 
     The two shunting grooves a 9  are grooves extending in the optical axis direction. The shunting grooves a 9  are formed so that the groove part is larger on the flange  132  side. More specifically, the shunting grooves a 9  have three portions, such as a first groove a 91 , a second groove a 92 , and a third groove a 93 . With the first groove a 91  and the second groove a 92 , the shape of their cross section perpendicular to the optical axis is circular, semi-elliptical, trapezoidal, rectangular, parabolic, or a combination of these. 
     The first groove a 91  is a groove part formed on the flange  132  side, that is, the second groove a 92  is a groove part formed on the subject side. The width and depth of the first groove a 91  are greater than the width and depth of the second groove a 92 . The third groove a 93  is in the form of a sloped face, a conical face, a curved face, or a shape that is a combination of these, so as to smoothly change from the width and depth of the first groove a 91  to the width and depth of the second groove a 92 . When shunting protrusions  404  (see  FIG. 15A ) of the OIS frame  400  (discussed below) are disposed in the first grooves a 91 , the shunting protrusions  404  are movable inside the first grooves a 91 . Specifically, in this case the OIS frame  400  is movable within a plane perpendicular to the optical axis with respect to the third rectilinear frame  130  or the shutter frame  335 . 
     The second groove a 92  is a groove part extending in the optical axis direction from the first groove a 91 . When the shunting protrusions  404  (see  FIG. 15A ) of the OIS frame  400  (discussed below) are disposed in the second grooves a 92 , the OIS frame  400  is constricted in the radial direction and the peripheral direction with respect to the third rectilinear frame  130  or the shutter frame  335 . Consequently, movement of the OIS frame  400  in a plane perpendicular to the optical axis is restricted with respect to the third rectilinear frame  130  or the shutter frame  335 . 
     The third groove a 93  is a groove part extending in the optical axis direction, and connects the first groove a 91  and the second groove a 92 . When the shunting protrusions  404  (see  FIG. 15A ) of the OIS frame  400  (discussed below) are disposed in the third grooves a 93 , the OIS frame  400  transitions from a state of being movable within a plane perpendicular to the optical axis with respect to the third rectilinear frame  130  or the shutter frame  335 , to a state of being gradually restricted in the radial direction and the peripheral direction. 
     Specifically, when the shunting protrusions  404  of the OIS frame  400  are disposed from the first grooves a 91 , via the third grooves a 93 , in the second grooves a 92 , this positions the OIS frame  400  in the plane perpendicular to the optical axis. 
     The mechanism for positioning the OIS frame  400  (positioning mechanism) is constituted by engagement of the shunting grooves a 9  (a 91 , a 92 , and a 93 ) of the third rectilinear frame  130  with the shunting protrusions  404  of the OIS frame  400 , and by engagement of the guide groove a 7  with the driven portion  411 . About the timing of this engagement, when there is a change from the image blur correction enabled position to the retracted position, first the engagement of the guide groove a 7  and the driven portion  411  begins. After this, the engagement of the guide groove a 7  and the driven portion  411  begins. This prevent the OIS frame  400  from end up moving in the direction of escaping, when the retracting lens frame  401  starts to rotate in the retraction direction and a force is exerted on the driven portion  411  from the guide groove a 7 . 
     7. Configuration of First Lens Group Frame  310   
       FIG. 11  is an oblique view of the first lens group frame  310 . The first lens group frame  310  has a first lens group frame main body  311 , three rectilinear protrusions A 4 , and three cam followers B 3 . 
     The first lens group frame main body  311  is formed in a cylindrical shape, and has an inner peripheral face  310 S and an outer peripheral face  310 T. Three protrusions  311   a  that protrude toward the rear are formed on the first lens group frame main body  311 . 
     The three rectilinear protrusions A 4  are provided to the outer peripheral face  310 T of the protrusions  311   a , and are disposed at a substantially constant pitch in the peripheral direction. The three rectilinear protrusions A 4  are engaged with the three rectilinear grooves a 4  of the second rectilinear frame  120 . 
     The three cam followers B 3  are provided to the inner peripheral face  310 S of the protrusions  311   a , and are disposed at a substantially constant pitch in the peripheral direction. The three cam followers B 3  are engaged with the three cam grooves b 3  of the second rotary frame  220 . 
     The three cams b 6  are formed only at the wall-shaped contact faces. The three cams b 6  are disposed at a substantially constant pitch in the peripheral direction on the inner peripheral face  310 S so as to intersect the optical axis direction. The three cams b 6  are engaged with the three cam follows B 6  of the second rotary frame  220 . 
     In this embodiment, the three rectilinear protrusions A 4  and the three cam followers B 3  are disposed substantially opposite each other. In other words, the protrusions  311   a  is disposed between each of the three rectilinear protrusions A 4  and the three cam followers B 3 . 
     8. Configuration of Second Lens Group Frame  320   
       FIG. 12A  is an oblique view of the second lens group frame  320 .  FIG. 12B  is a view of the second lens group frame  320  from the front.  FIG. 12C  is an oblique view of the relation between the second lens group frame  320  and the sheet member  324 . 
     As shown in  FIG. 12A , the second lens group frame  320  has a second lens group frame main body  321 , a second lens support  321 L for supporting the second lens group L 2 , a housing receptacle  322  (an example of a restrictor that restricts movement of the retracting lens frame  401 ; discussed below), a housing portion  323 , three rectilinear protrusions A 5 , and three cam followers B 4 . 
     The second lens group frame main body  321  is formed in a cup shape, and has an outer peripheral face  320 T. 
     The housing receptacle  322  is used to position the retracting lens frame  401  by restricting movement of the retracting lens frame  401 , and coming into contact with the positioning portion  412  of the retracting lens frame  401 , during the transition period between the imaging enabled state and the housed state. As shown in  FIG. 12A , the housing receptacle  322  is formed integrally with the second lens group frame main body  321 . More precisely, the housing receptacle  322  is formed integrally with the second lens group frame main body  321  on the outer peripheral part of the second lens support  321 L (the portion supporting the second lens group L 2 ). The housing receptacle  322  has the guide portion  322   a  that guides the retracting lens frame  401  to the retracted position by coming into contact with the positioning portion  412  of the retracting lens frame  401 , and the support portion  322   b  that supports the retracting lens frame  401  at the retracted position (see  FIG. 17A ). 
     The guide portion  322   a  has a sloped face. The sloped face is formed so that the distance from the optical axis AX decreases as a position on the sloped face moves toward the imaging element side along the optical axis AX. 
     The cam mechanism constituted by the guide groove a 7  and the driven portion  411  changes the orientation of the retracting lens frame  401 , when the third rectilinear frame  130  moves relatively in the optical axis direction with respect to the retracting lens frame  401 . After this, the retracting lens frame  401  is guided to the retracted position by contacting the positioning portion  412  of the retracting lens frame  401  with the guide portion  322   a  (sloped face). 
     The support portion  322   b  is a portion extending in the optical axis direction, and supports the retracting lens frame  401 . As discussed above, the positioning portion  412  of the retracting lens frame  401  guided by the guide portion  322   a  is supported in a state of being in contact with the support portion  322   b.    
     As shown in  FIGS. 12A to 12C , the housing portion  323  is a portion for housing at least part of the OIS frame  400  and the retracting lens frame  401  in the retracted state. The housing portion  323  has a first housing portion  323   a  and a second housing portion  323   b.    
     The first housing portion  323   a  is used to house a second linking portion  408  of the OIS frame  400  (discussed below). The first housing portion  323   a  is a hole provided on the front face side of the second lens group frame main body  321 . The first housing portion  323   a  is provided above the second lens group L 2 . 
     In the second lens group L 2 , the upper and lower outer peripheral parts of the lens are cut in the flat. Specifically, the second lens group L 2  is formed in an oval shape as seen in the optical axis direction. The upper and lower portions on the front face side of the second lens group frame main body  321  are wider than the other portion. Accordingly, the second lens group frame  320  has adequate strength even though a hole is provided on the front face side of the second lens group frame main body  321 . The reason that the outer peripheral parts of the upper and lower portions of the lens in the second lens group L 2  can be cut in the flat that is, the reason that the second lens group L 2  can have an oval shape as seen in the optical axis direction, is that an imaging element  103  is formed in a rectangular shape. That is, since the imaging element  103  is rectangular in shape, the range of the light beams passing through the second lens group L 2  becomes in the shape of a rectangular ring. Therefore, in the example disclosed here, the hole on the front face side of the second lens group frame main body  321  is provided above, but the same effect is obtained if it is provided below. 
     The first housing portion  323   a  is formed in a shape substantially similar to the outer shape of the second linking portion  408 . Also, at least part of the first housing portion  323   a  and at least part of the second linking portion  408  overlap in the optical axis direction. This allows the size of the lens barrel  20  to be smaller in the optical axis direction in the housed state. 
     The second housing portion  323   b  is used to house the retraction shaft  501   b , part of the retracting lens frame  401 , part of the OIS frame  400 , part of the shutter frame  335 , an OIS rotary shaft  334 , and a thrust spring  402 . The second housing portion  323   b  is a hole provided on the front face side of the second lens group frame main body  321 . The second housing portion  323   b  is formed in a shape corresponding to the parts to be housed. 
     As shown in  FIG. 12B , the sheet member  324  is affixed to the front face of the second lens group frame  320 . The sheet member  324  prevents light from leaking out of the hole in the front face of the second lens group frame  320  (including the housing portion  323 ), and also improves the aesthetics. 
     The three rectilinear protrusions A 5  are formed on the rear end of the outer peripheral face  320 T, and are disposed at a substantially constant pitch in the peripheral direction. The three rectilinear protrusions A 5  are engaged with the three rectilinear grooves a 5  of the third rectilinear frame  130 . 
     The three cam followers B 4  are formed on the three rectilinear protrusions A 5 , that is, on the outside in the radial direction. The three cam followers B 4  are engaged with the three cam grooves b 4  of the second rotary frame  220 . 
     9. Configuration of Third Lens Group Frame  330   
       FIG. 13A  shows the state when the third lens group frame  330  has been housed in the interior of the shutter frame  335 . The configuration of the third lens group frame  330  will be described through reference to  FIG. 13A . 
     The third lens group frame  330  (an OIS (optical image stabilizer) unit) mainly has the OIS frame  400  (an example of a support frame), the retracting lens frame  401 , the thrust spring  402  (an example of a first biasing means), the rotary spring  403  (an example of a second biasing means, and an example of a biasing member), the third lens group L 3  for image blur correction, and two magnets  521 . 
     As shown in  FIGS. 13A and 14A , the OIS frame  400  is mounted to the shutter frame  335 . The optical axis direction position of the OIS frame  400  with respect to the shutter frame  335  is maintained because three OIS shafts  339  that are press-fitted to the shutter frame  335  are inserted into optical axis direction maintenance portions  415  at three places on the OIS frame  400  (only two of the optical axis direction maintenance portions  415  are shown in  FIG. 14A ). As shown in  FIG. 14A , the position of the OIS frame  400  in a direction perpendicular to the optical axis with respect to the shutter frame  335  is maintained because one OIS rotary shaft  334  press-fitted to the shutter frame  335  is inserted into a perpendicular direction maintenance portion  416  at one place on the OIS frame  400  in a direction perpendicular to the optical axis, and a perpendicular direction stopper pin  409  comes into contact with the peripheral wall of a movable range restrictor  338  of the OIS frame  400  (see  FIG. 18B ). 
     As shown in  FIGS. 14A and 15A , a space ST is formed in the OIS frame  400  in order to house the third lens support  420  that supports the third lens group L 3  supported by the retracting lens frame  401  in the imaging enabled state. When the retracting lens frame  401  has been retracted, the second lens support  321 L of the second lens group frame  320  is housed in this space ST. 
     The OIS frame  400  also has a main body portion  405 , a first linking portion  407 , and the second linking portion  408 . The main body portion  405  has a hole  405   a  (an example of a first region) and a retraction portion  405   b  (an example of a second region). 
     The hole  405   a  forms the above-mentioned space ST. The hole  405   a  is formed in the center of the main body portion  405 . The third lens support  420  that supports the third lens group L 3  in the imaging enabled state is disposed in the hole  405   a . The hole  405   a  also houses the second lens support  321 L of the second lens group frame  320  when retracted. 
     Part of the lower inner peripheral part of the hole  405   a  is formed in a straight line. Specifically, the hole  405   a  is formed in an oval shape or a D shape. The reason for this is that the upper and lower portions of the outer peripheral part of the second lens support  32  IL housed in the hole  405   a  when retracted are formed in a shape that is cut in the flat. Specifically, this is because part of the lower part of the second lens support  321 L is formed in a straight line. In other words, the second lens support  321 L is formed in an oval shape or a D shape when viewed in the optical axis direction. The hole  405   a  is formed so as to correspond to this shape of the second lens support  321 L. 
     The reason why the upper and lower portions of the outer peripheral part of the second lens support  321 L are formed in a shape that is cut in the flat, that is, in an oval shape or a D shape when viewed in the optical axis direction, is that the lens of the second lens group L 2  is formed in the same shape. That is, the second lens support  321 L is formed so as to correspond to the lens shape of the second lens group L 2 . 
     This ensures there is a region to dispose members under the OIS frame  400 . The magnets  521 , which are part of the image blur correction mechanism, are disposed in this region. Also, if the hole  405   a  is provided to the OIS frame  400 , a decrease in the strength of the second lens group frame  320  can be reduced. 
     Since the imaging element  103  is formed in rectangular shape, the second lens group L 2  is formed so that the upper and lower portions of the outer peripheral part of the lens have a shape that is cut in the flat, that is, an oval shape or a D shape when viewed in the optical axis direction. This is because the range of the light beams passing through the second lens group L 2  is in the shape of a rectangular ring. Therefore, in the example disclosed here, the portion of the hole  405   a  of the OIS frame  400  formed in a straight line, that is, the straight part of the D shape, is provided below, but the same effect is obtained if it is provided above. 
     The retraction portion  405   b  is formed continuously with the hole  405   a . The retraction portion  405   b  is formed on the outer peripheral part of the main body portion  405 . 
     The first linking portion  407  serves to increase the strength of the main body portion  405 . The first linking portion  407  is formed integrally with the main body portion  405 . The first linking portion  407  is formed integrally with the main body portion  405  on one side of the retraction portion  405   b  in the optical axis direction. 
     More specifically, the first linking portion  407  spans the retraction portion  405   b  on the shutter frame  335  side of the main body portion  405 , and is formed integrally with the main body portion  405 . Also, the first linking portion  407  is disposed on the outside of the opening of the shutter frame  335  when viewed in the optical axis direction. Also, the first linking portion  407  is disposed on the outside of the second lens support  32  IL of the second lens group frame  320 , that is, on the outside in the radial direction, when viewed in the optical axis direction. Therefore, since the first linking portion  407  and the second lens support  321 L do not overlap in the optical axis direction when retracted, the second lens group frame  320  can be moved closer to the shutter frame  335  when retracted, and this results in a smaller lens barrel  20 . 
     As shown in  FIGS. 14B and 15A , the first linking portion  407  is formed on the main body portion  405  so that the maximum width of the first linking portion  407  in a direction perpendicular to the optical axis becomes less than the maximum width of the second linking portion  408  in a direction perpendicular to the optical axis. 
     As shown in  FIG. 14B , the first linking portion  407  is formed on the main body portion  405  so that the maximum thickness of the first linking portion  407  in the optical axis direction is less than the maximum thickness of the second linking portion  408  in the optical axis direction. 
     Also, as shown in  FIGS. 13B and 14B , the portion of the shutter frame  335  that is opposite the first linking portion  407  at the face of a shutter frame main body  336  on the front side in the optical axis direction is locally made thinner, and the first linking portion  407  goes into this thinner part  350 . Specifically, at least part of the shutter frame  335  and at least part of the first linking portion  407  overlap in the optical axis direction. This allows the lens barrel  20  to be even smaller in the optical axis direction. 
     Also, the thinner part  350  is formed in the shutter frame main body  336  of the shutter frame  335  so that the clearance between the first linking portion  407  and the thinner part  350  in a direction perpendicular to the optical axis becomes greater than the clearance between the second linking portion  408  and the first housing portion  323   a  in a direction perpendicular to the optical axis. 
     In the imaging enabled state, the OIS frame  400  moves in a direction perpendicular to the optical axis with respect to the shutter frame  335  for image blur correction. The OIS frame  400  moves closer to the shutter frame  335  in the optical axis direction in the imaging enabled state, and the first linking portion  407  goes into the thinner part  350 . However, in the imaging enabled state, the OIS frame  400  does not move closer to the front face of the second lens group frame main body  321 , and the second linking portion  408  is not housed in the first housing portion  323   a . A state in which the second linking portion  408  is housed in the first housing portion  323   a  occurs only in the retracted state. Therefore, the clearance between the first linking portion  407  and the thinner part  350  in a direction perpendicular to the optical axis must be set to at least the amount of movement of the OIS frame  400  in a direction perpendicular to the optical axis in order to prevent interference during image blur correction. On the other hand, the clearance between the second linking portion  408  and the first housing portion  323   a  in a direction perpendicular to the optical axis does not need to take into account the above-mentioned amount of movement. It is for this reason that the clearance is formed as discussed above. 
     The protrusions  404  (see  FIG. 15A ) used to position the OIS frame  400  substantially at an optical axis position protrude in the radial direction from the side faces of the OIS frame  400 . These protrusions  404  are inserted into the side walls of the shutter frame main body  336 , and therefore the side wall holes  351  are provided in the shutter frame main body  336  side walls. The OIS frame  400  comprises side walls  417  that substantially cover the side wall holes  351  in the shutter frame main body  336 . This prevents light from leaking through the side wall holes  351  in the shutter frame main body  336 . 
     As shown in  FIG. 13B , three light blocking walls  352  that protrude in the radial direction are formed on the side faces of the shutter frame main body  336 . The peripheral direction positions of the light blocking walls  352  correspond to the peripheral direction positions of the three rectilinear grooves a 5  of the third rectilinear frame  130 . The peripheral direction width of the three light blocking walls  352  is substantially the same as or less than the peripheral direction width of the three rectilinear grooves a 5  of the third rectilinear frame  130 . This prevents light from leaking out through the three rectilinear grooves a 5  of the third rectilinear frame  130 . 
     As shown in  FIG. 15A , the OIS frame  400  has the shunting protrusions  404  that engage with the shunting grooves a 9  of the third rectilinear frame  130 . The shunting protrusions  404  are formed integrally with the main body portion  405  of the OIS frame  400 . More specifically, the two shunting protrusions  404  are formed on the main body portion  405  so as to protrude outward from the outer peripheral part of the main body portion  405 . Also, the two shunting protrusions  404  are formed integrally with the main body portion  405 , spaced apart by a specific distance, around the outer peripheral part of the main body portion  405 . The two shunting protrusions  404  are respectively fitted into and guided by the two shunting grooves a 9  of the third rectilinear frame  130 . 
     More specifically, when the OIS frame  400  moves closer to the third rectilinear frame  130  in a state in which the OIS frame  400  has been mounted to the shutter frame  335 , the shunting protrusions  404  formed on the OIS frame  400  are introduced from the flange  132  side of the third rectilinear frame  130  into the first grooves a 91  of the third rectilinear frame  130 . In a state in which the shunting protrusions  404  are disposed in the first grooves a 91 , the OIS frame  400  is movable within a plane perpendicular to the third rectilinear frame  130  or the shutter frame  335 . 
     Then, when the OIS frame  400  moves further in the optical axis direction on the inner peripheral side of the third rectilinear frame  130  in a state in which the OIS frame  400  has been mounted to the shutter frame  335 , the shunting protrusions  404  are introduced into the third grooves a 93 . As a result, the OIS frame  400  gradually transitions from a state of being movable within a plane perpendicular to the optical axis with respect to the third rectilinear frame  130  or the shutter frame  335 , to a state of being restricted in the radial direction and the peripheral direction. 
     When the shunting protrusions  404  are then introduced into the second grooves a 92 , the second grooves a 92  press the shunting protrusions  404  in the direction of the optical axis center from the inner peripheral face  130 S of the third rectilinear frame  130 . Consequently, movement of the OIS frame  400  is restricted in a plane perpendicular to the optical axis with respect to the third rectilinear frame  130  or the shutter frame  335 . This positions the OIS frame  400 . The positioning of the OIS frame  400  in this embodiment is carried out before the retracting lens frame  401  begins to retract, but what is important is that the positioning be completed by the time the retraction operation is complete. 
     In a state in which the OIS frame  400  has been mounted to the shutter frame  335 , the first linking portion  407  is disposed above the magnets  521  and a coil  522  (actuator) that are discussed below. 
     The second linking portion  408  is provided to increase the strength of the main body portion  405  and to block light to the imaging element side. That is, the second linking portion  408  is also used as a light blocking portion. The second linking portion  408  is formed integrally with the main body portion  405 . As compared to the case that the first linking portion  407  and the second linking portion  408  are both provided and the case that just the first linking portion  407  or the second linking portion  408  is provided, the strength of the main body portion  405 , which is decreased by providing the retraction portion  405   b , can be increased. There also is less deterioration in accuracy during injection molding. 
     The second linking portion  408  is formed integrally with the main body portion  405  on the other side of the retraction portion  405   b  in the optical axis direction, that is, the opposite side from that of the first linking portion  407  in the optical axis direction. 
     More specifically, the second linking portion  408  is formed integrally with the main body portion  405  and spans the retraction portion  405   b  on the subject side of the main body portion  405 . Also, the second linking portion  408  is disposed on the outside of the second lens group L 2  when viewed in the optical axis direction. 
     As discussed above, the first linking portion  407  is disposed on the outside of the opening of the shutter frame  335  when viewed in the optical axis direction. Also, the radius of the second lens group L 2  is greater than the radius of the opening in the shutter frame  335  in a direction perpendicular to the optical axis. Because of this, the inner peripheral part of the first linking portion  407  can be disposed more on the inside in the radial direction than the inner peripheral part of the second linking portion  408 . 
     In the example disclosed here, when viewed in the optical axis direction, the inner peripheral part of the second linking portion  408  and the inner peripheral part of the first linking portion  407  are disposed more to the outside in the radial direction than the outside diameter of the second lens support  321 L. 
     Also, the inner peripheral part of the second linking portion  408  is disposed more to the outside in the radial direction than the inner peripheral part of the first linking portion  407 . This is because the outside diameter of the second lens support  321 L, that is, the front side in the optical axis direction (the side opposite the second linking portion  408 ) is greater than the rear side in the optical axis direction (the side opposite the first linking portion  407 ). Thus, the inner peripheral part of the second linking portion  408  and the inner peripheral part of the first linking portion  407  are disposed so as to correspond to the outside diameter of the second lens support  321 L. 
     In the end, the shape of the first linking portion  407  and the shape of the inner peripheral part of the second linking portion  408  should correspond to the external shape with the largest outside diameter out of all the frames disposed in the hole  405   a  (the second lens support  321 L and the third lens support  420 ), either in the imaging enabled state or the retracted state. Specifically, the shape of the first linking portion  407  and the shape of the inner peripheral part of the second linking portion  408  should correspond to a shape that conforms to the external shape the member at the farthest distance from the optical axis. This allows the lens barrel  20  to be made smaller while ensuring good strength of the OIS frame  400  and maintaining good moldability. 
     Also, at least part of the portion where the second linking portion  408  is opposite the third lens group L 3  is formed so as to correspond to a curved face that encompasses the region through which the third lens group L 3  passes during the transition from imaging to retraction (including during imaging and during retraction), and follow this curved face (see  FIG. 14B ). In other words, the region of the second linking portion  408  that is not opposite the curved face of the third lens group L 3  during the transition is formed thicker. On the other hand, the region of the second linking portion  408  that is opposite the curved face of the third lens group L 3  during the transition is formed thinner. 
     This allows the lens barrel  20  to be made smaller while ensuring good strength of the OIS frame  400  and maintaining good moldability. Of course, the shape may be further thinned so that there is no undercut during sliding of the mold, and so as to encompass the curved face of the third lens group L 3 , according to the sliding direction of the mold during injection molding. The same effect is obtained in this case as well. 
     The second linking portion  408  is provided at a position a specific distance away from the main body portion  405 . The second linking portion  408  is also provided at a position a specific distance away from the first linking portion  407 . 
     When the retracting lens frame  401  is in its retracted state (housed state), the third lens support  420  that supports the third lens group L 3  is disposed on the retraction portion  405   b  between the first linking portion  407  and the second linking portion  408 . 
     The OIS frame  400  is movable in a plane perpendicular to the optical axis. More specifically, the magnets  521  are fixed to the OIS frame  400 , and the coil  522  is fixed to the shutter frame  335  at a position opposite the magnets  521 . In this state, when power is supplied from a camera circuit (not shown) to the coil  522  of the shutter frame  335 , current flows to the coil  522  and a magnetic field is generated. This magnetic field drives the magnets  521  of the OIS frame  400 , and this drive force causes the OIS frame  400  to move within a plane perpendicular to the optical axis. 
     As shown in  FIG. 15A , the OIS frame  400  further has three rail portions  503 . The three rail portions  503  ( 503   a  to  503   c ) are formed on the main body portion  405 . The rail portions  503  are formed on one face of the substantially disk-shaped main body portion  405 . The rail portions  503  are formed on the main body portion  405  at positions opposite a contact face  603  formed on the retracting lens frame  401  (the first contact face  603 A discussed below). 
     The rail portions  503  are formed on the portion of the main body portion  405  excluding the range where the third lens group L 3  supported by the retracting lens frame  401  moves. Furthermore, the rail portions  503  are formed in a shape corresponding to the path over which the contact face  603  (first contact face  603 A; discussed below) moves when the lens barrel  20  transitions from the imaging enabled state to the retracted state. 
     As shown in  FIGS. 15A and 15B , the OIS frame  400  further has an anti-rotation portion  511 . The anti-rotation portion  511  is used to position the retracting lens frame  401  in the imaging enabled state. The anti-rotation portion  511  is formed integrally with the outer peripheral part of the main body portion  405 . 
     As shown in  FIG. 15B , a recess  512  is formed in the anti-rotation portion  511 . A second contact face  603 B of the retracting lens frame  401  (discussed below) comes into contact with one of two side walls  512   a  of the recess  512 . More specifically, the side walls  512   a  are formed at positions a specific distance away from the surface of the main body portion  405 . These side walls  512   a  are sloped so that they move closer to the opposite side wall (the surface of the main body portion  405 ) as they move toward the bottom of the recess  512 . This sloping pushes the second contact face  603 B of the retracting lens frame  401  toward the OIS frame  400 , and presses the second contact face  603 B of the retracting lens frame  401  against the contact face  512   c  of the OIS frame  400 . 
     As shown in  FIG. 14A , the retracting lens frame  401  is supported by the OIS frame  400  so as to be movable around the retraction shaft  501   b , which is substantially parallel to the optical axis. The retracting lens frame  401  supports the third lens group L 3  used to image blur correction with the third lens support  420 . The third lens group L 3  is made up of one or more lenses. 
     The term “retraction shaft” as used below will sometimes be used in the sense of “the axis of the retraction shaft.” 
     As shown in  FIG. 14A , the retracting lens frame  401  has a main body portion  401   a , a bearing  410 , the driven portion  411 , the positioning portion  412  (see  FIGS. 17A and 19 ), the third lens support  420 , and an engagement portion  413 . The bearing  410  is formed integrally with the main body portion  401   a.    
     As shown in  FIGS. 14A and 15A , the bearing  410  is rotatably mounted to the support shaft  501   b  (retraction shaft) provided to the OIS frame  400 . As shown in  FIGS. 16A and 16B , a hole into which the retraction shaft  501   b  is inserted is formed in the bearing  410 . At least two contact faces  601   a  that come into contact with the retraction shaft  501   b  are formed in the hole of the bearing  410 . In other words, the two contact faces  601   a  are formed in the inner peripheral face of the bearing  410 . 
     The two contact faces  601   a  are formed on the inner peripheral face of the bearing  410  on the proximal end side of the retraction shaft  501   b , that is, on the opening side of the bearing  410  (hole). The two contact faces  601   a  are formed on the inner peripheral face of the bearing  410  so as to be in a mutually non-parallel relation. More specifically, when the bearing  410  (hole) is viewed in the depth direction, the two contact faces  601   a  are formed on the inner peripheral face of the bearing  410  so as to form an angle. 
     As shown in  FIG. 16B , the two contact faces  601   a  (hereinafter referred to as V-faces) come into contact with the outer peripheral face of the retraction shaft  501   b . More specifically, the retracting lens frame  401  is biased by the biasing force F 0  of the rotary spring  403  (see  FIG. 16A ), and the component force F 1  of this biasing force F 0  causes the V-faces  601   a  of the bearing  410  to come into contact with the outer peripheral face of the retraction shaft  501   b.    
     As discussed below, in this embodiment, the other end  403   b  of the rotary spring  403  is bent. When the other end  403   b  of the rotary spring  403  is thus formed, the component force F 1 , that is, the force at which the contact faces  601   a  of the bearing  410  are brought into contact with the outer peripheral face of the retraction shaft  501   b , can be increased over when the other end  403   b  of the rotary spring  403  is formed in a straight line. 
     This allows the retraction shaft  501   b  to be reliably positioned with respect to the bearing  410  of the retracting lens frame  401 . More precisely, accuracy with respect to eccentricity of the retraction shaft  501   b  can be increased. The component forces of the biasing force F 0  in  FIG. 16A  are F 1  and F 2 . 
     The driven portion  411  is a portion that is driven against the biasing force of the rotary spring  403  (discussed below) during the transition period between the imaging enabled state and the housed state. As shown in  FIGS. 14A and 19 , the driven portion  411  is formed integrally and protrudes outward from the main body portion  401   a . The driven portion  411  engages with the guide groove a 7  formed in the inner peripheral face of the third rectilinear frame  130 . More precisely, the driven portion  411  engages with the guide groove a 7  of the third rectilinear frame  130  via an opening SK 1  (discussed below) in the shutter frame  335 . The driven portion  411  moves relatively in the optical axis direction with respect to the retracting lens frame  401 , and is thereby guided in the guide groove a 7  of the third rectilinear frame  130 . This changes the orientation of the retracting lens frame  401  between the imaging enabled state and the retracted state. 
     The positioning portion  412  is formed on a portion (the third lens support  420 ) of the retracting lens frame  401  that supports the third lens group L 3 . The positioning portion  412  is positioned by the housing receptacle  322  of the second lens group frame  320  during the transition period between the imaging enabled state and the housed state. 
     The positioning portion  412  is formed so that the distance between the positioning portion  412  and the retraction shaft  501   b  becomes greater than the distance between the driven portion  411  and the retraction shaft  501   b . More precisely, as shown in  FIG. 14A , the positioning portion  412  is formed so that the distance LK 1  between the axis of the retraction shaft  501   b  and the position where the positioning portion  412  comes into contact with the housing receptacle  322  becomes greater than the distance LK 2  between the axis of the retraction shaft  501   b  and the proximal end of the driven portion  411 . 
     As shown in  FIGS. 14A,17A, and 17B , the third lens support  420  is a portion that supports the third lens group L 3 . The third lens support  420  is in the form of a cylinder. The third lens group L 3  is mounted on the inside of the third lens support  420 . 
     As shown in  FIG. 17B , the third lens support  420  has a cut-out  420   a , which is a portion with no wall on the outside of the third lens group L 3 . The cut-out  420   a  is provided to the outer peripheral part of the third lens support  420 . More specifically, the cut-out  420   a  is a portion that is partially cut away from the outer peripheral part of the third lens support  420 . More precisely, in the cut-out  420   a , the side of the outer peripheral part of the third lens support  420  that is away from the optical axis in the imaging enabled state, when the retracting lens frame  401  is in the retracted state, is cut away. The cut-out  420   a  is disposed opposite a light blocking portion  357  (see  FIG. 14A ) of the shutter frame  335  (discussed below) during the transition period between the imaging enabled state and the housed state. 
     As shown in  FIGS. 14A and 18C , the third lens support  420  is disposed between the second linking portion  408  and the face on the front side in the optical axis direction of the shutter frame main body  336  of the shutter frame  335  during the transition period between the imaging enabled state and the housed state. Also, the third lens support  420  is disposed between the second linking portion  408  and the first linking portion  407  when it has entered the thinner part  350  of the face on the front side in the optical axis direction of the shutter frame main body  336 . At least part of the shutter frame  335  overlaps at least part of the first linking portion  407  in the optical axis direction. This allows the lens barrel  20  to be smaller in the optical axis direction in its housed state. 
     As shown in  FIGS. 18A to 18C , a first engagement portion  413   a  is a portion capable of engaging with a first restrictor  337   a  of the shutter frame  335  (discussed below). Also, a second engagement portion  413   b  is a portion capable of engaging with the second linking portion  408  of the OIS frame  400  (discussed below). The engagement portions here constitute the first engagement portion  413   a  that engages with the first restrictor  337   a  (discussed below), and the second engagement portion  413   b  that engages with the second linking portion  408 , which acts as a restrictor during the transition period between the imaging enabled state and the housed state. 
     As shown in  FIGS. 18A and 18B , the first engagement portion  413   a  is formed near the retraction shaft  501   b . As shown in  FIG. 18B , the first engagement portion  413   a  is disposed between the first restrictor  337   a  and the OIS frame  400 . The second engagement portion  413   b  is formed on the third lens support  420  that supports the third lens group L 3 . The second engagement portion  413   b  is disposed opposite the second linking portion  408  formed on the OIS frame  400 , during the transition period between the imaging enabled state and the housed state. 
     As shown in  FIG. 19 , the retracting lens frame  401  further has the plurality of contact portions  603  ( 603 A and  603 B). The contact portions  603  are formed integrally with the main body portion  401   a  of the retracting lens frame  401 . The contact portions  603  are made up of three first contact portions  603 A ( 603 A 1 ,  603 A 2 , and  603 A 3 ) and a second contact portion  603 B. 
     The three first contact portions  603 A and the second contact portion  603 B are formed integrally with the main body portion  401   a  at a different position from the bearing  410 . In other words, the three first contact portions  603 A and the second contact portion  603 B are formed on the main body portion  401   a  at a different position from the retraction shaft  501   b  supported by the bearing  410 . Also, the three first contact portions  603 A and the second contact portion  603 B are formed on the main body portion  401   a  at a different position from the retraction shaft  501   b  so as to be capable of contact with the OIS frame  400 . 
     More precisely, the two contact portions  603 A 1  and  603 A 2  out of the three first contact portions  603 A are formed on the main body portion  401   a  near the retraction shaft  501   b . The two contact portions  603 A  1  and  603 A 2  are formed on the main body portion  401   a  so that the retraction shaft  501   b  is located between the two contact portions  603 A 1  and  603 A 2 . The other first contact portion  603 A 3  besides these two contact portions  603 A  1  and  603 A 2 , and the second contact portion  603 B are formed on the main body portion  401   a  at a position that is away from the retraction shaft  501   b.    
     The three first contact portions  603 A( 603 A 1 ,  603 A 2 , and  603 A 3 ) shown in  FIG. 19  are able to come into contact with the OIS frame  400 . Specifically, when the three first contact portions  603 A come into contact with the OIS frame  400 , movement of the retracting lens frame  401  in the optical axis direction is restricted. 
     More precisely, when the three first contact portions  603 A come into contact with the rail portions  503  of the OIS frame  400  (see  FIG. 15A ), movement of the retracting lens frame  401  in the optical axis direction is restricted. More specifically, when the lens barrel  20  is in its imaging enabled state, the three first contact portions  603 A 1 ,  603 A 2 , and  603 A 3  come into contact with the rail portions  503   a ,  503   b , and  503   c  of the OIS frame  400 . The first contact portion  603 A  1  comes into contact with the rail portion  503   a , the first contact portion  603 A 2  comes into contact with the rail portion  503   b , and the first contact portion  603 A 3  comes into contact with the rail portion  503   c.    
     When the three first contact portions  603 A thus hit the rail portions  503  of the OIS frame  400 , this restricts movement of the retracting lens frame  401  in the optical axis direction. 
     The second contact portion  603 B shown in  FIG. 19  is used to position the retracting lens frame  401  on the OIS frame  400  in the imaging enabled state. The second contact portion  603 B comes into contact with the anti-rotation portion  511  of the OIS frame  400  in the imaging enabled state. The outer peripheral part of the second contact portion  603 B is formed so as to mate with the anti-rotation portion  511  of the OIS frame  400 . For example, the outer peripheral part of the second contact portion  603 B is formed in a tapered shape (see  FIG. 15B ). When the second contact portion  603 B is fitted into the recess  512  of the anti-rotation portion  511  of the OIS frame  400 , the retracting lens frame  401  can be reliably positioned in the imaging enabled state. 
     As shown in  FIG. 14A , the thrust spring  402  is a spring that biases the retracting lens frame  401  in the optical axis direction with respect to the OIS frame  400 . The thrust spring  402  is formed in an approximate C shape. One end of the thrust spring  402  is mounted to the OIS frame  400 , and the other end of the thrust spring  402  is mounted to the retracting lens frame  401 . Consequently, the retracting lens frame  401  and the OIS frame  400  are clamped by the thrust spring  402  in the optical axis direction. 
     As shown in  FIG. 14A , the rotary spring  403  is a spring that biases the retracting lens frame  401  around a retraction shaft  510 , that is, in a direction perpendicular to the optical axis. The rotary spring  403  is supported by the OIS frame  400 . The rotary spring  403  is a torsion coil spring, for example. The coil portion of the rotary spring  403  is disposed on the outer periphery of the bearing  410 . 
     One end  403   a  of the rotary spring  403  is clamped by latching portions  504   a  and  504   b  (see  FIG. 15A ) formed on the OIS frame  400 . As shown in  FIG. 16A , the other end  403   b  of the rotary spring  403  is mounted in a groove  605  formed in the retracting lens frame  401 . The other end  403   b  of the rotary spring  403  is bent in two stages. 
     As shown in  FIG. 16A , the other end  403   b  of the rotary spring  403  has a first bent part  403   b   1  formed on the distal end side, and a second bent part  403   b   2  formed in the middle. The first bent part  403   b   1  and the second bent part  403   b   2  are bent so as to follow the outer shape of the third lens support  420  of the retracting lens frame  401 . In this case, the first bent part  403   b   1  is mounted in the groove  605  formed in the retracting lens frame  401 . 
     As shown in  FIG. 16A , the first bent part  403   b   1  and the second bent part  403   b   2  are bent so that a specific angle α is formed by a specific straight line (horizontal line) passing through the axis of the retraction shaft  501   b , and the first bent part  403   b   1  of the other end  403   b  of the rotary spring  403 . 
     Thus forming the other end  403   b  of the rotary spring  403  increases the force (component force F 1 ) at which the contact faces  601   a  of the bearing  410  come into contact with the outer peripheral face of the retraction shaft  501   b , as discussed above. This allows the retraction shaft  501   b  to the reliably positioned with respect to the bearing  410  of the retracting lens frame  401 . 
     Because the rotary spring  403  biases the retracting lens frame  401  as discussed above, the second contact portion  603 B of the retracting lens frame  401  comes into contact with the anti-rotation portion  511  of the OIS frame  400  (see  FIGS. 13A and 15B ). The OIS frame  400  is positioned when the bearing  410  is mounted to the retraction shaft  501   b  of the OIS frame  400 , and the second contact portion  603 B comes into contact with the anti-rotation portion  511  of the OIS frame  400 . 
     As shown in  FIGS. 17A and 17B , the position of the retracting lens frame  401  can be changed from a correction enabled position in which the third lens group L 3  executes image blur correction (first orientation), to a retracted position in which the third lens group L 3  has been retracted from the optical axis (second orientation). The retracting lens frame  401  supports the third lens group L 3 , which is made up of at least one lens. 
     As shown in  FIG. 17A , when the retracting lens frame  401  is in the correction enabled position, the center of the second lens group L 2  and the center of the third lens group L 3  are located on the optical axis AX. 
     When the retracting lens frame  401  begins to retract, the retracting lens frame  401  and the second lens support  321 L of the second lens frame  320  move closer together while the retracting lens frame  401  rotates. This causes the positioning portion  412  of the retracting lens frame  401  to come into contact with the guide portion  322   a  of the second lens frame  320 . The positioning portion  412  then moves over the guide portion  322   a  and reaches the support portion  322   b , and is supported by the support portion  322   b . Thus, the retracting lens frame  401  is supported by the second lens frame  320 . 
       FIG. 17B  shows this state. That is, as shown in  FIG. 17B , when the retracting lens frame  401  moves to the retracted position, the retracting lens frame  401  comes into contact with the support portion  322   b  of the second lens group frame  320 , and is housed in the space of the second lens group frame  320 , that is, in the space between the second lens support  321 L and the outer peripheral face  320 T (see  FIG. 12A ). More specifically, the retracting lens frame  401  is supported and housed in a state of being in contact with the support portion  322   b  of the second lens frame  320  within the space on the outside in the radial direction of the second lens group L 2 . 
     10. Configuration of Shutter Frame  335   
     The configuration of the shutter frame  335  will now be described through reference to  FIGS. 13A, 14A, and 18A to 18C . As shown in  FIG. 13A , the shutter frame  335  has the shutter frame main body  336 , three rectilinear protrusions A 6 , and the three cam followers B 5 . Also, as shown in  FIG. 14A , the shutter frame  335  has an opening  356 , the light blocking portion  357 , and the first restrictor  337   a.    
     The shutter frame main body  336  is formed in a cylindrical shape, and has an outer peripheral face  335 T. 
     The three rectilinear protrusions A 6  are formed on the outer peripheral face  335 T, and are disposed at a substantially constant pitch in the peripheral direction. The three rectilinear protrusions A 6  are engaged with the three rectilinear grooves a 6  of the third rectilinear frame  130 . 
     The three cam followers B 5  are provided to the front end of the three rectilinear protrusions A 6 . The three cam followers B 5  are engaged with the three cam grooves b 5  of the second rotary frame  220 . 
     The opening  356  is a portion that houses a part  420   b  of the third lens support  420  during the transition period between the imaging enabled state and the housed state. As shown in  FIG. 14A , the part  420   b  of the third lens support  420  is the portion adjacent to the cut-out  420   a  during the transition period between the imaging enabled state and the housed state. More precisely, the light blocking portion  357  is provided to the opening  356  in order to block light rays. 
     As shown in  FIGS. 18A to 18C , the restrictor is a portion that can restrict movement of the retracting lens frame  401  in the optical axis direction. The restrictor has a first restrictor  337   a  formed near the retraction shaft  501   b , and a second linking portion  408  that acts as a second restrictor and is formed at a position that is away from the retraction shaft  501   b.    
     The first restrictor  337   a  is formed integrally with the shutter frame main body  336  on the front side (the subject side) of the first engagement portion  413   a . More specifically, the first restrictor  337   a  spans the space SK 1  (see  FIG. 18B ) that houses the members near the retraction shaft  501   b , on the front side (the subject side) of the first engagement portion  413   a . The first restrictor  337   a  restricts movement of the retracting lens frame  401  in the optical axis direction near the retraction shaft  501   b , in the imaging enabled state and the retracted state. 
     The second linking portion  408  is formed integrally with the OIS frame  400 . More specifically, when the retracting lens frame  401  is in the retracted state, the second linking portion  408  spans the space SK 2  on the front side (the subject side) of the space SK 2  (see  FIG. 14A ) that houses the third lens group L 3 . The second linking portion  408  restricts movement of the retracting lens frame  401  in the optical axis direction near the third lens group L 3  in the retracted state. 
     During normal operation, that is, when no strong force is acting on the retracting lens frame  401 , such as during an imaging operation, or when the power is switched on or off, the retracting lens frame  401  is clamped to the OIS frame  400  by the thrust spring  402 , and its position is restricted in the optical axis direction. Therefore, the first restrictor  337   a  and the second linking portion  408  do not individually come into contact with the first engagement portion  413   a  and the second engagement portion  413   b . However, if a strong force (such as when the camera is dropped) is exerted in the optical axis direction, the retracting lens frame  401  moves in the optical axis direction with respect to the OIS frame  400  against the force of the thrust spring  402 . 
     When a strong force (such as when the camera is dropped) is exerted in the optical axis direction, the retracting lens frame  401  moves in the optical axis direction with respect to the OIS frame  400 , and the first restrictor  337   a  comes into contact with the first engagement portion  413   a . Accordingly, the thrust spring  402  can always be operated in its elastic range. Here, the engagement of a contact portion  414  with an anti-rotation portion  511  contributes to keeping the thrust spring  402  in its elastic range. 
     When a strong force (such as when the camera is dropped) is exerted in the optical axis direction in the retracted state, the retracting lens frame  401  moves in the optical axis direction with respect to the OIS frame  400 , and the first restrictor  337   a  and the second linking portion  408  individually come into contact with the first engagement portion  413   a  and the second engagement portion  413   b . Consequently, the thrust spring  402  can always be operated in its elastic range. 
     11. Engagement of Frames 
       FIGS. 20 to 22  are cross sections of the lens barrel  20 . Noted that  FIGS. 20 to 22  are schematics that combine a plurality of cross sections passing through the optical axis AX. The lens barrel  20  is shown in its retracted state in  FIG. 20 , in its wide angle state in  FIG. 21 , and in its telephoto state in  FIG. 22 . In this embodiment, the “imaging enabled state” of the digital camera  1  means a state from the wide angle state to the telephoto state of the lens barrel  20 . 
     The gear portion  212  of the first rotary frame  210  meshes with the zoom gear  242  (not shown). The cam followers B 1  of the first rotary frame  210  are engaged with the cam grooves b 1  of the stationary frame  100 . Therefore, the first rotary frame  210  is movable in the optical axis direction while rotating in the peripheral direction under the drive force of the zoom motor  241 . 
     The rectilinear protrusions A 1  of the first rectilinear frame  110  are engaged with the rectilinear grooves a 1  of the stationary frame  100 . The bayonet protrusions E 1  of the first rotary frame  210  are engaged with the bayonet groove e 1  of the first rectilinear frame  110 . Therefore, the first rectilinear frame  110  is movable rectilinearly in the optical axis direction along with the first rotary frame  210 . 
     The rectilinear cam followers AB 2  of the second rectilinear frame  120  are inserted into the cam grooves b 2  of the first rotary frame  210 , and are engaged with the rectilinear grooves a 2  of the first rectilinear frame  110 . Therefore, the second rectilinear frame  120  is movable rectilinearly in the optical axis direction according to the rotation of the first rotary frame  210 . 
     The rectilinear protrusions A 3  of the second rotary frame  220  are engaged with the rectilinear grooves a 3  of the first rotary frame  210 . The bayonet protrusions E 2  of the second rotary frame  220  are engaged with the bayonet groove e 2  of the second rectilinear frame  120 . Therefore, the second rotary frame  220  is movable in the optical axis direction along with the second rectilinear frame  120  while rotating in the peripheral direction along with the first rotary frame  210 . 
     The latching portions  122  of the second rectilinear frame  120  are latched to the latching recesses  133  of the third rectilinear frame  130 . The bayonet protrusions E 3  of the third rectilinear frame  130  are engaged with the bayonet grooves e 3  of the second rotary frame  220 . The spacing of at least two of the rectilinear protrusions A 3  of the second rotary frame  220  is approximately 120° or more, the spacing of the two latching portions  122  of the second rectilinear frame  120  is approximately 120° or more, and the relative rotational angle during these during zoom drive is approximately 120° or less. Accordingly, the latching portions  122  and the rectilinear protrusions A 3  are disposed at the same positions in the radial direction and the optical axis direction, but are disposed at different positions in the rotational angle direction, that is, the peripheral direction, and the third rectilinear frame  130  is movable rectilinearly in the optical axis direction along with the second rectilinear frame  120  without interfering with the rotation of the second rotary frame  220 . 
     One of the two latching portions  122  is formed longer in the peripheral direction than the other one, and one of the latching recesses  133  is formed longer in the peripheral direction than the other one as well, but the third rectilinear frame  130  is preferably made longer in the peripheral direction in the range that it does not interfere with the rotation of the second rotary frame  220 . 
     The spacing of at least two of the three rectilinear protrusions A 3  of the second rotary frame  220  is approximately 150°, the spacing of the two latching portions  122  of the second rectilinear frame  120  is approximately 150°, and the relative rotational angle during these during zoom drive is approximately 150° or less. Therefore, the third rectilinear frame  130  does not interfere with the rotation of the second rotary frame  220 . The same applies to the other angles. 
     The rectilinear protrusions A 4  of the first lens group frame  310  are engaged with the rectilinear grooves a 4  of the second rectilinear frame  120 . Also, the cam followers B 3  of the first lens group frame  310  are engaged with the cam grooves b 3  of the second rotary frame  220 . Therefore, the first lens group frame  310  is movable rectilinearly in the optical axis direction according to the rotation of the second rotary frame  220 . 
     The cams b 6  of the first lens group frame  310  engage with the cam followers B 6  of the second rotary frame  220 . The first lens group frame  310  and the second rotary frame  220  are engaged by two cam mechanisms, such as the cam mechanism b 3  and the cam followers B 3 , and the cams b 6  and the cam followers B 6 . This prevents damage or dislocation of the frames in the event that an external force is exerted from the subject side in the optical axis direction when the camera is dropped, etc. 
     The rectilinear protrusions A 5  of the second lens group frame  320  are engaged with the rectilinear grooves a 5  of the third rectilinear frame  130 . Also, the cam followers B 4  of the second lens group frame  320  are engaged with the cam grooves b 4  of the second rotary frame  220 . Therefore, the second lens group frame  320  is movable rectilinearly in the optical axis direction according to the rotation of the second rotary frame  220 . 
     The rectilinear protrusions A 6  of the shutter frame  335  are engaged with the rectilinear grooves a 6  of the third rectilinear frame  130 . Also, the cam followers B 5  of the shutter frame  335  are engaged with the cam grooves b 5  of the second rotary frame  220 . Therefore, the shutter frame  335  is movable rectilinearly in the optical axis direction according to the rotation of the second rotary frame  220 . 
     The third lens group frame  330  is mounted to the shutter frame  335 , and when the shutter frame  335  moves rectilinearly in the optical axis direction with respect to the third rectilinear frame  130 , the retracting lens frame  401  of the third lens group frame  330  is rotated by a retraction mechanism (the guide groove a 7  of the third rectilinear frame  130  and the driven portion  411  of the retracting lens frame  401 ). Consequently, in a transition from the retracted state to the imaging enabled state, the retracting lens frame  401  moves from its retracted position to a correction enabled position. Also, in a transition from the imaging enabled state to the retracted state, the retracting lens frame  401  moves from the correction enabled position to the retracted position. When the retracting lens frame  401  is disposed in the correction enabled position, the third lens group L 3  is movable within a plane perpendicular to the optical axis. That is, image blur correction is possible in this state. 
     Thus, the lens group frames  310 ,  320 , and  335  and the first to third rectilinear frames  110  to  130  move rectilinearly by the rotation of the first rotary frame  210  and the second rotary frame  220  under the 
     Method for Assembling the Lens Barrel  20   
     The method for assembling the lens barrel  20  will now be described. 
     First, the third rectilinear frame  130  is inserted from the rear of the second rotary frame  220 . The third rectilinear frame  130  is then rotated in the peripheral direction to set the telephoto state. 
     Next, the second lens group frame  320  is inserted from the rear of the third rectilinear frame  130 . 
     Next, the retracting lens frame  401  is inserted from the front of the OIS frame  400 , and the retracting lens frame  401  is rotatably attached to the OIS frame  400 . 
     Next, the OIS frame  400  is inserted from the front of the shutter frame  335 . 
     Next, the shutter frame  335  is inserted from the rear of the third rectilinear frame  130 . The second rotary frame  220  is then rotated in the peripheral direction to set the retracted state. 
     Next, the second rotary frame  220  is inserted from the rear of the first lens group frame  310 . 
     Next, the second rectilinear frame  120  covers the first lens group frame  31  from the front of the first lens group frame  310 . 
     Next, the first rotary frame  210  is inserted from the rear of the first rectilinear frame  110 . The second rectilinear frame  120  is then inserted from the rear of the first rotary frame  210 . 
     Next, the first rectilinear frame  110  is inserted from the rear of the stationary frame  100 . 
     Finally, the first rotary frame  210  is rotated with respect to the stationary frame  100  to set the retracted state. 
     Operation and Orientation of Retraction Lens Frame 
     The operation and orientation of the retraction lens frame will now be described in detail. 
     When the lens barrel  20  transitions from the imaging enabled state to the retracted state, the retracting lens frame  401  is moved by a retraction mechanism (the guide groove a 7  of the third rectilinear frame  130  and the driven portion  411  of the retracting lens frame  401 ) from the correction enabled position to the retracted position. Specifically, the retraction mechanism changes the orientation of the retracting lens frame  401  from an imaging enabled state to a retracted state. When the lens barrel  20  transitions from the retracted state to the imaging enabled state, the above operation is performed in reverse to change the orientation of the retracting lens frame  401  between the imaging enabled state and the retracted state. 
     The retraction mechanism will now be described in detail. The cam mechanism, which operates based on engagement of the cam followers B 5  and the cam grooves b 5  of the second rotary frame  220 , causes the shutter frame  335  to move rectilinearly in the optical axis direction according to the rotation of the second rotary frame  220 . The retracting lens frame  401  integrally engages with the shutter frame  335  as discussed below, and the above-mentioned cam mechanism causes it to move relatively in the optical axis direction with respect to the third rectilinear frame  130  from the imaging enabled state to the retracted state. In the process of transitioning from the imaging enabled state to the retracted state, the driven portion  411  engages with the driven portion  411  and moves along the path of the guide groove a 7 . The guide groove a 7  is a cam groove formed in the inner face of the third rectilinear frame  130 . The driven portion  411  is a cam follower. As shown in  FIG. 9A , a portion (the sloped part a 71 ) that is sloped with respect to the optical axis and a portion (the parallel part a 72 ) that is parallel to the optical axis are formed on the guide groove a 7 . When the driven portion  411  moves along this sloped part a 71 , the retracting lens frame  401  rotates around the retraction shaft  501   b . The retracting lens frame  401  transitions between an image blur correction position and a retracted position by rotating around the retraction shaft  501   b.    
     The retracting lens frame  401  integrally engages with the OIS frame  400  in the optical axis direction, and the OIS frame  400  integrally engages with the shutter frame  335  in the optical axis direction. Accordingly, the movement of the retracting lens frame  401  with respect to the third rectilinear frame  130  in the optical axis direction is the same as the movement of the shutter frame  335  with respect to the third rectilinear frame  130  in the optical axis direction. The rectilinear protrusions A 6  of the shutter frame  335  are engaged with the rectilinear grooves a 6  of the third rectilinear frame  130 . Also, the cam followers B 5  of the shutter frame  335  are engaged with the cam grooves b 5  of the second rotary frame  220 . Therefore, the shutter frame  335  is movable rectilinearly in the optical axis direction according to the rotation of the second rotary frame  220 . 
     The OIS frame  400  supported by the shutter frame  335  is positioned in a direction perpendicular to the optical axis by the third rectilinear frame  130  before the retracting lens frame  401  begins to retract. For example, if a transition from the imaging enabled state to the housed state (that is, the retracted state) is performed, when the shutter frame  335  moves rectilinearly in the optical axis direction, the shunting protrusions  404  of the OIS frame  400  supported by the shutter frame  335  are mated with the shunting grooves a 9  of the third rectilinear frame  130  from the flange  132  side of the third rectilinear frame  130 . When the shutter frame  335  then moves rectilinearly further in the optical axis direction, the shunting protrusions  404  are pressed by the shunting grooves a 9 , and the OIS frame  400  is restricted with respect to the shutter frame  335 . Thus, the positioning of the OIS frame  400  in a direction perpendicular to the optical axis is executed before the retracting lens frame  401  begins its retraction operation. 
     When the retracting lens frame  401  supported by the shutter frame  335  moves from the image blur correction enabled position (that is the imaging enabled position) to the retracted position, the retracting lens frame  401  is rotated by a retraction mechanism constituting the driven portion  411  of the retracting lens frame  401  and the guide groove a 7  of the third rectilinear frame main body  131 , on the inside of the third rectilinear frame main body  131 . During this time, the retracting lens frame  401  and the second lens support  321 L of the second lens frame  320  move closer together in the optical axis direction. In a state of having been placed on the shutter frame  335 , the retracting lens frame  401  is moved in the optical axis direction by the cam mechanism operated by engagement of the cam followers B 5  and the cam grooves b 5  of the second rotary frame  220 , and the second lens frame  320  is moved in the optical axis direction by the cam mechanism operated by engagement of the cam followers B 4  and the cam grooves b 4  of the second rotary frame  220 . The retracting lens frame  401  and the second lens frame  320  move closer together based on the difference in the paths of the cam grooves b 5  and the cam grooves b 4 . The positioning portion  412  of the retracting lens frame  401  is then guided by the guide portion  322   a  of the second lens frame  320  and comes into contact with the support portion  322   b  (see  FIG. 17A ). Consequently, in a state that the retracting lens frame has come into contact with the support portion  322   b  of the second lens frame  320 , the retracting lens frame  401  is housed in the space of the second lens frame  320 , that is, in the space between the second lens support  321 L and the outer peripheral face  320 T. More specifically, the retracting lens frame  401  is supported and housed in a state of being in contact with the support portion  322   b  of the second lens frame  320  within the space on the outside in the radial direction of the second lens group L 2 . 
     At this point, the second linking portion  408  of the OIS frame  400  is housed in the first housing portion  323   a  of the second lens frame  320 , and the retraction shaft  501   b , part of the retracting lens frame  401 , part of the OIS frame  400 , part of the shutter frame  335 , the OIS rotary shaft  334 , and the thrust spring  402  are housed in the second housing portion  323   b  of the second lens frame  320  (see  FIGS. 12A to 12C ). 
     Also, at this point, the first linking portion  407  of the OIS frame  400  is housed in the thinner part  350  of the face of the shutter frame main body  336  on the front side in the optical axis direction. 
     As shown in  FIG. 17B , in this state, the second lens support  321 L of the second lens frame  320  is housed in the space ST of the OIS frame  400  (see  FIG. 14A ). 
     Also, in this state, one end of the thrust spring  402  is mounted to the OIS frame  400 , and the other end of the thrust spring  402  is mounted to the retracting lens frame  401 . Consequently, the retracting lens frame  401  and the OIS frame  400  are clamped and positioned in the optical axis direction by the thrust spring  402 . 
     Also, in this state, the third lens support  420  of the retracting lens frame  401  is disposed between the first linking portion  407  and the second linking portion  408 . Also, the first engagement portion  413   a  (first engagement portion) near the drive axis of the retracting lens frame  401  is disposed between the first restrictor  337   a  and the OIS frame  400 . Consequently, as discussed above, movement of the retracting lens frame  401  in the optical axis direction can be restricted in the event that a powerful force (such as when the camera is dropped) is exerted in the optical axis direction. 
     Also, in this state, the cut-out  420   a  formed in the third lens support  420  of the retracting lens frame  401  is disposed opposite the light blocking portion  357  of the shutter frame  335 . Also, the opening  356  in the shutter frame  335  houses the part  420   b  of the third lens support  420 . 
     Meanwhile, when the lens barrel is in the imaging enabled state, the bearing  410  of the retracting lens frame  401  is mated with the retraction shaft  501   b  of the OIS frame  400 , and the contact portion  414  of the retracting lens frame  401  comes into contact with the anti-rotation portion  511  of the OIS frame  400 , thereby the retracting lens frame  401  is positioned with respect to the OIS frame  400  (see  FIG. 13A ). 
     Also, in this state, one end of the thrust spring  402  is mounted to the OIS frame  400 , and the other end of the thrust spring  402  is mounted to the retracting lens frame  401 . Consequently, the retracting lens frame  401  and the OIS frame  400  are clamped and positioned by the thrust spring  402  in the optical axis direction. 
     Also, in this state, image blur correction on the OIS frame  400  can be accomplished by using the third lens group L 3  of the retracting lens frame  401 . 
     Also, in this state, the first engagement portion  413   a  (first engagement portion) near the drive axis of the retracting lens frame  401  is disposed between the first restrictor  337   a  and the OIS frame  400 . Consequently, as discussed above, movement of the retracting lens frame  401  in the optical axis direction can be restricted in the event that a powerful force (such as when the camera is dropped) is exerted in the optical axis direction. 
     Action and Effect 
     (1) This lens barrel  20  comprises the second lens group L 2 , the third rectilinear frame  130 , the shutter frame  335 , and the retracting lens frame  401 . The retracting lens frame  401  is configured to support the third lens group L 3 . The shutter frame  335  is configured to move in the optical axis direction of the second lens group L 2  with respect to the third rectilinear frame  130 . The retracting lens frame  401  is configured to be supported by the shutter frame  335 , and move so that a position of the optical axis of the third lens group L 3  changes from a position on the optical axis of the second lens group L 2  to a position that is outside the optical axis of the second lens group L 2  during the transition period between the imaging enabled state and the housed state. 
     The third rectilinear frame  130  includes a third rectilinear frame main body  131 . The guide groove a 7  is formed in the inner peripheral part of the third rectilinear frame main body  131 . The guide groove a 7  includes at least one side wall. The at least one side wall is configured to stand inward from the inner peripheral part of the third rectilinear frame main body  131 . 
     The retracting lens frame  401  includes the driven portion  411 . The driven portion  411  is configured to engage with and guided by the guide groove a 7  when the retracting lens frame  401  moves around the retraction shaft. The thickness of the region constituting the side walls of the guide groove a 7  is increased over the thickness of the other region toward the inside of the third rectilinear frame main body  131 . The “other region” referred to here is the portion opposite the third lens support  420  of the retracting lens frame  401  in the housed state, on the inside in the radial direction of the third rectilinear frame main body  131 , or is the portion opposite the actuator installed in the shutter frame  335 . 
     With this lens barrel  20 , the orientation of the retracting lens frame  401  is changed by a cam mechanism (the guide groove a 7  and the driven portion  411 ). More specifically, the orientation of the retracting lens frame  401  is changed when the driven portion  411  is engaged with and guided by the guide groove a 7 . 
     Because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , rotation of the retracting lens frame  401  can be started earlier during the transition period between the imaging enabled state and the housed state. This is because the guide groove a 7  and the driven portion  411  are always in close positions that allow engagement. 
     Also, because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , the rotational accuracy of the retracting lens frame  401  can be increased. This is because there are relatively few parts between the driven portion  411  and the guide groove a 7 . 
     Also, because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , the guide groove a 7  can be easily constituted by three faces, namely, the side face a 73  on the front side in the optical axis direction, the side face a 74  on the rear side in the optical axis direction, and the bottom face a 75  that is parallel to the optical axis and connects the above-mentioned two faces, and the strength of the guide groove a 7  can also be increased. This is because the third rectilinear frame  130  is cylindrical. 
     Furthermore, because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , positioning can be performed more accurately in a plane that is perpendicular to the optical axis during retraction. This is because a mechanism for positioning the third rectilinear frame  130  in a plane that is perpendicular to the optical axis is formed with the third rectilinear frame  130 . 
     The thickness of the third rectilinear frame main body  131  is preferably as thin as possible in order to reduce the outside diameter of the lens barrel  20 . The thickness of the portion opposite the relatively large parts disposed on the inside in the radial direction of the third rectilinear frame main body  131  is preferably reduced. For example, in the housed state, the thickness of the portion opposite the third lens support  420  of the retracting lens frame  401  is preferably reduced. Also, the thickness of the portion opposite the actuators installed on the shutter frame  335  (such as the motor for driving the shutter vanes, the motor for aperture drive, the motor for driving the ND vanes, the coil for correcting image blur, and the magnet for correcting image blur) is preferably reduced. However, the cam mechanism for moving the retracting lens frame  401 , that is, the portion where the guide groove a 7  and the driven portion  411  engage, needs to be strong. Therefore, with this lens barrel  20 , the thickness of the portion where the guide groove a 7  and the driven portion  411  engage, that is, in the region constituting the side wall of the guide groove a 7 , is increased over that in the other region, facing toward the inside of the third rectilinear frame main body  131 . More specifically, in the region constituting the side wall of the guide groove a 7 , the reinforcing portion  130 H is formed on the inside of the third rectilinear frame main body  131 . This ensures that the third rectilinear frame main body  131  is strong while suppressing an increase in the outside diameter of the third rectilinear frame main body  131 . Specifically, the lens barrel  20  can be made smaller. The shutter frame  335 , the OIS frame  400 , and the second lens group frame  320  move in the optical axis direction on the inside in the radial direction of the third rectilinear frame  130 . Therefore, for the purpose of preventing interference, the portions of the shutter frame  335 , the OIS frame  400 , and the second lens group frame  320  that are opposite the reinforcing portion  130 H are reduced in thickness as compared to the other portions, that is, they are made smaller in the radial direction. 
     (2) With this lens barrel  20 , the region constituting the side wall of the guide groove a 7  includes the area near the portion where the guide groove a 7  is formed. More specifically, the reinforcing portion  130 H is formed near the portion where the guide groove a 7  is formed. Even more specifically, the reinforcing portion  130 H is formed adjacent to the guide groove a 7 . 
     (3) With this lens barrel  20 , the guide groove a 7  is formed in a groove shape. The guide groove a 7  includes two opposing side walls. In this case, since the guide groove a 7  is formed in a groove shape, when the retracting lens frame  401  is rotated, the driven portion  411  hits one face (one of the side faces) of the guide groove a 7 . Accordingly, the retracting lens frame  401  if just this one side face is provided. However, because the guide groove a 7  is formed in a groove shape, the position of the driven portion  411  is reliably maintained by the guide groove a 7  even if the camera is dropped, subjected to an impact, etc., so the orientation of the retracting lens frame  401  can be kept stable. Furthermore, even if the rotational load of the retracting lens frame  401  is increased over the rotational force of the rotary spring  403  due to the influence of wear through continuous use or of the adhesion of foreign matter in the guide groove a 7 , the retracting lens frame  401  can still be forcibly rotated. 
     The reinforcing portion  130 H is formed thick enough to accommodate the depth (that is, the radial direction dimension) of the guide groove a 7 . The depth (that is, the radial direction dimension) of the guide groove a 7  needs to accommodate the height (that is, the radial direction dimension) of the driven portion  411 . Accordingly, during cam mechanism operation, the driven portion  411  can be stably guided inside the guide groove a 7 . 
     (4) Prior art has been disclosed in which, when the lens barrel transitions from an imaging state to a housed state, an insertion/removal member that supports a second lens group is rotated and retracted from the optical axis of a first lens group by a removal control protrusion provided to an imaging element holder (see the above-mentioned Japanese Laid-Open Patent Application 2011-150132). Also, with this technology, when the insertion/removal member has retracted, it is supported by the removal control protrusion provided to the imaging element holder (see FIG. 15 in the above-mentioned Japanese Laid-Open Patent Application 2011-150132). 
     With prior art, the removal control protrusion is provided to the imaging element holder in order to retract the insertion/removal member. Also, a removal control member is provided to the imaging element holder in order to support the retracted insertion/removal member. Accordingly, space for providing the removal control protrusion and the insertion/removal member needs to be ensured in the imaging element holder, thereby it is difficult to reduce the size of the lens barrel. 
     Also, since the insertion/removal member is retracted and supported by the removal control protrusion and the removal control member provided to the imaging element holder, the layout relation to the imaging element holder has to be taken into account, which affords less freedom in designing the lens barrel. 
     The technology disclosed herein was conceived in light of the above problems, and it is an object thereof to increase design latitude while reducing the size of the lens barrel. 
     The lens barrel comprises a first frame, a second frame, and a retracting lens frame. The second frame is configured to be supported movably in the optical axis direction with respect to the first frame on the inside of the first frame. The retracting lens frame is configured to be supported by the second frame and support at least one lens. The first frame includes a contact portion on at least its inner peripheral face. The retracting lens frame includes a protrusion. The protrusion is configured to engage with the contact portion during the transition period between the imaging enabled state and the housed state. Also, the retracting lens frame moves in a direction that is perpendicular to the optical axis with respect to the second frame when the protrusion moves along the contact portion. 
     The technology disclosed herein provides a lens barrel with which there is greater design latitude while the size of the lens barrel is reduced. 
     The lens barrel disclosed herein is as given below. 
     (4-1) 
     A lens barrel, comprising: 
     a first frame; 
     a second frame is configured to be supported movably in the optical axis direction with respect to the first frame on the inside of the first frame; and 
     a retracting lens frame is configured to be supported by the second frame and supports at least one lens, 
     the first frame includes a contact portion on its inner peripheral face, and 
     the retracting lens frame includes a protrusion, the protrusion configured to engage with the contact portion and move in a direction perpendicular to the optical axis with respect to the second frame when the protrusion moves along the contact portion during the transition period between the imaging enabled state and the housed state. 
     (4-2) 
     The lens barrel according to (4-1), further comprising: 
     a third frame configured to be rotatably supported with respect to the first frame on the outside of the first frame, wherein 
     the first frame includes a through-groove, the through-groove configured to extend at least in the optical axis direction, 
     the third frame includes a guide groove in its inner peripheral face, and 
     the second frame includes a cam follower, the cam follower configured to be inserted through the through-groove and engage with the guide groove. 
     (4-3) 
     The lens barrel according to (4-2), wherein 
     the first frame and the second frame configured to unrotate relatively, and 
     the through-groove configured to extend parallel to the optical axis direction. 
     (4-4) 
     The lens barrel according to (4-2), wherein 
     the first frame and the second frame configured to unrotate relatively, 
     the second frame and the third frame configured to unrotate relatively, and 
     the through-groove configured to extend parallel to the optical axis direction and the peripheral direction. 
     (4-5) 
     The lens barrel according to any of (4-1) to (4-4), comprising: 
     a biasing member configured to be supported by the second frame and biase the retracting lens frame in a direction perpendicular to the optical axis; and 
     a rectilinear lens frame configured to support at least one lens, at least part of the rectilinear lens frame moving into a space prior to the movement of the retracting lens frame in the housed state, wherein 
     the retracting lens frame includes a driven portion, the driven portion configured to be driven against the biasing force of the biasing member during the transition period between the imaging enabled state and the housed state, and a positioning portion configured to be positioned by the rectilinear lens frame in the housed state, 
     the rectilinear lens frame includes a restrictor, the restrictor configured to come into contact with the positioning portion in the housed state, and 
     the distance between the positioning portion and the retraction shaft is greater than the distance between the driven portion and the retraction shaft. 
     (4-6) 
     The lens barrel according to (4-5), wherein 
     the restrictor includes a guide portion, the guide portion configured to guide the retracting lens frame to a retracted position, and a support portion configured to support the retracting lens frame in the retracted position. 
     The above configurations and effects will now be described in specific terms. 
     (4-6) This lens barrel  20  comprises the third rectilinear frame  130 , the shutter frame  335  and/or the OIS frame  400 , and the retracting lens frame  401 . The shutter frame  335  and/or the OIS frame  400  is configured to be supported movably in the optical axis direction with respect to the third rectilinear frame  130  on the inside of the third rectilinear frame  130 . The retracting lens frame  401  is configured to be supported by the shutter frame  335  and/or the OIS frame  400 , and support the third lens group L 3 . The third rectilinear frame  130  includes the guide groove a 7  at least on its inner peripheral face. The retracting lens frame  401  includes the driven portion  411  that is engaged with the guide groove a 7 . The retracting lens frame  401  is configured to move in a direction perpendicular to the optical axis with respect to the shutter frame  335  and/or the OIS frame  400  when the driven portion  411  moves along the guide groove a 7  during the transition period between the imaging enabled state and the housed state. 
     With this lens barrel  20 , the guide groove a 7  that engages with the driven portion  411  is formed in the inner peripheral face of the third rectilinear frame  130 . Therefore, the three faces of the guide groove a 7  can be easily constituted. 
     For example, when the guide groove a 7  is provided to the stationary portion of the imaging element holder or the like, if an attempt is made to form the three faces constituting the guide groove a 7  in the stationary portion of the imaging element holder, then the stationary portion of the imaging element holder or the like end up being larger. Also, if the guide groove a 7  is formed in a small space in order to avoid making the stationary portion of the imaging element holder larger, the guide groove a 7  is not strong enough. 
     In contrast, with this lens barrel  20 , there is no need to form the guide groove a 7  in the stationary portion of the imaging element holder or the like, so the stationary portion of the imaging element holder can be made smaller. Also, in this case the portion where the guide groove a 7  is formed is cylindrical, so the strength of the guide groove a 7  can be increased. Also, since there is no need to take the layout relation with the imaging element holder into account, there is greater latitude in the design of the lens barrel. 
     Furthermore, because the guide groove a 7  that engages with the driven portion  411  is formed in the third rectilinear frame  130 , positioning can be performed more accurately during retraction. When the guide groove a 7  is provided to the third rectilinear frame  130 , a mechanism for positioning the OIS frame  400  is also determined by the third rectilinear frame  130 . Accordingly, there is better positioning accuracy of the retracting lens frame  401  and the OIS frame  400 . 
     (4-7) This lens barrel  20  further comprises a second rotary frame  220 . The second rotary frame  220  is configured to be supported rotatably with respect to the third rectilinear frame  130  on the outside of the third rectilinear frame  130 . The third rectilinear frame  130  includes a rectilinear groove a 6  that extends at least in the optical axis direction. The second rotary frame  220  includes a cam groove b 5  in its inner peripheral face. The shutter frame  335  includes a cam follower B 5 . The cam follower B 5  is inserted through the rectilinear groove a 6  and is engaged with the cam groove b 5 . 
     With this lens barrel  20 , when the second rotary frame  220  rotates, the shutter frame  335 , the OIS frame  400 , and the retracting lens frame  401  move in the optical axis direction on the inside of the third rectilinear frame  130 . At this point, the retracting lens frame  401  moves in a direction perpendicular to the optical axis with respect to the shutter frame  335  and the OIS frame  400 . 
     Thus, even though the second rotary frame  220  is supported rotatably with respect to the third rectilinear frame  130  on the outside of the third rectilinear frame  130 , the driven portion  411  and the guide groove a 7  can be provided and the retracting lens frame  401  can be operated, just as in (4-6). This gives the same effect as above. 
     (4-8) With this lens barrel  20 , the third rectilinear frame  130  and the shutter frame  335  and OIS frame  400  unrotate relatively. The rectilinear groove a 6  extends parallel to the optical axis direction. 
     With this lens barrel  20 , when the second rotary frame  220  rotates, the shutter frame  335 , the OIS frame  400 , and the retracting lens frame  401  move in the optical axis direction with respect to the third rectilinear frame  130  on the inside of the third rectilinear frame  130 . At this point, the retracting lens frame  401  moves in a direction perpendicular to the optical axis with respect to the shutter frame  335  and the OIS frame  400 . 
     Thus, even though the lens barrel  20  is configured so that the shutter frame  335  and the OIS frame  400  move in the optical axis direction with respect to the third rectilinear frame  130 , the driven portion  411  and the guide groove a 7  can be provided and the retracting lens frame  401  can be operated, just as in (4-6). This gives the same effect as above. 
     (4-9) This lens barrel  20  comprises a rotary spring  403  and a second lens group frame  320 . The rotary spring  403  is configured to be supported by the shutter frame  335  and biase the retracting lens frame  401  in a direction perpendicular to the optical axis. The second lens group frame  320  is configured to support the second lens group L 2 , and at least part of the second lens group frame  320  moves into a space prior to the movement of the retracting lens frame  401  in the housed state. The retracting lens frame  401  includes a driven portion  411  and a positioning portion  412 . The driven portion  411  is configured to be driven against the biasing force of the rotary spring  403  during the transition period between the imaging enabled state and the housed state. The positioning portion  412  is configured to be positioned by the second lens group frame  320  in the housed state. The second lens group frame  320  includes a housing receptacle  322 . The housing receptacle  322  is configured to come into contact with the positioning portion  412  in the housed state. The distance between the positioning portion  412  and the retraction shaft  501   b  is greater than the distance between the driven portion  411  and the retraction shaft  501   b.    
     With this lens barrel  20 , at least part of the second lens group frame  320  goes into a space prior to the movement of the retracting lens frame  401  in the housed state. More specifically, a second lens support  321 L of the second lens group frame  320  is housed in a space ST of the retracting lens frame  401 . 
     Because the second lens support  321 L of the second lens group frame  320  is thus housed in the space ST of the retracting lens frame  401 , the lens barrel  20  can be made smaller in the optical axis direction. 
     Also, the second lens group frame  320  has the housing receptacle  322  that comes into contact with the positioning portion  412  in the housed state. In the housed state, the positioning portion  412  of the retracting lens frame  401  is positioned by the second lens group frame  320 . More specifically, the positioning portion  412  of the retracting lens frame  401  comes into contact with the housing receptacle  322  of the second lens group frame  320 . 
     Because the housing receptacle  322  for positioning the retracting lens frame  401  is thus provided to the second lens group frame  320 , the third lens support  420  of the retracting lens frame  401  can be closer to the second lens support  321 L of the second lens group frame  320 , which allows the OIS frame  400  to be smaller. 
     Also, when the retracting lens frame  401  is mounted to the OIS frame  400 , a stiff spring is used for the rotary spring  403  in order to suppress shake of the retracting lens frame  401  during OIS control. Accordingly, there is the risk that a large amount of stress is generated around the retraction shaft  501   b  of the retracting lens frame  401 . Specifically, with prior art, there is the risk that creep deformation occurs in the retracting lens frame  401 . With this lens barrel  20 , however, the retracting lens frame  401  is positioned by the second lens group frame  320 , which has plenty of volume, so creep deformation can be prevented. 
     Also, since the retracting lens frame  401  is positioned by the second lens group frame  320  at a position that is far away from the driven portion  411  of the retracting lens frame  401  (the position of the positioning portion  412 ), using the retraction shaft  501   b  as a reference, the stress that occurs in the positioning portion  412  can be reduced. 
     Furthermore, since the retracting lens frame  401  is positioned by the second lens group frame  320  at the positioning portion  412 , using the retraction shaft  501   b  as a reference, the position where the retracting lens frame  401  is stopped during retraction can be more accurate. Specifically, since there is better accuracy in the stopping position of the retracting lens frame  401  during retraction, there is no need to factor in stopping error, and the lens barrel  20  can be made smaller. 
     (4-10) With this lens barrel  20 , the housing receptacle  322  includes a guide portion  322   a  and a support portion  322   b . The guide portion  322   a  is configured to guide the retracting lens frame  401  to the retracted position. The support portion  322   b  is configured to support the retracting lens frame  401  in the retracted position. 
     Since the guide portion  322   a  is thus provided to the housing receptacle  322  of the second lens group frame  320 , the retracting lens frame  401  can be guided smoothly to the retracted position by this guide portion  322   a . Also, since the support portion  322   b  is provided to the housing receptacle  322  of the second lens group frame  320 , the retracting lens frame  401  can be reliably supported in the retracted position. 
     Other Embodiments 
     (A) In the above embodiment, the lens barrel  20  had a three-stage telescoping design made up of the first rectilinear frame  110 , the second rectilinear frame  120 , and the first lens group frame  310 , but this is not the only option. The lens barrel  20  may instead have a two-stage telescoping design made up of the first rectilinear frame  110  and the second rectilinear frame  120 . In this case, the lens barrel  20  need not comprise the second rotary frame  220  or the third rectilinear frame  130 . The lens barrel  20  may also have a four-stage or higher telescoping design. 
     (B) In the above embodiment, the cam grooves b were formed on one of two frames, and the cam followers B were formed on the other frame, but this is not the only option. The cam followers B may be formed on one of two frames, and the cam grooves b formed on the other frame. Also, the cam grooves b and the cam followers B may be formed on each of two frames. 
     (C) In the above embodiment, the rectilinear grooves a were formed on one of two frames, and the rectilinear protrusions A were formed on the other frame, but this is not the only option. The rectilinear protrusions A may be formed on one of two frames, and the rectilinear grooves a formed on the other frame. Also, the rectilinear grooves a and the rectilinear protrusions A may be formed on each of two frames. 
     (D) In the above embodiment, the bayonet grooves e were formed on one of two frames, and the bayonet protrusions E were formed on the other frame, but this is not the only option. The bayonet protrusions E may be formed on one of two frames, and the bayonet grooves e formed on the other frame. Also, the bayonet grooves e and the bayonet protrusions E may be formed on each of two frames. 
     (E) In the above embodiment, the third lens group frame  330  was retracted toward the second lens group frame  320  in the retracted state, but this is not the only option. The third lens group frame  330  may be disposed to the rear of the second lens group frame  320  in the retracted state. 
     (F) In the above embodiment, as shown by the broken line in  FIG. 23A , the other end  403   b  of the rotary spring  403  is formed so as to extend away from the axis KJ of the coil part at a position of 90 degrees with reference to the axis KJ of the coil portion of the rotary spring  403  (the axis of the coil part, the axis of the retraction shaft  501   b ). Instead, as shown by the solid line in  FIG. 23A , the other end  403   b  of the rotary spring  403  may be formed so as to extend away from the axis KJ of the coil part at a position of 90 degrees with reference to the axis KJ of the coil part. 
     In this case, just as in the above embodiment, if the rotary spring  403  is mounted to the OIS frame  400  and the retracting lens frame  401 , the force FP at which the retracting lens frame  401  is pressed against the OIS frame  400  can be generated, as shown in  FIG. 23B . This allows the three first contact portions  603 A ( 603 A 1 ,  603 A 2 , and  603 A 3 ) of the retracting lens frame  401  to be reliably brought into contact by the OIS frame  400 . 
     (G) In the above embodiment, an example was given in which, when the second rotary frame  220  (third frame body) rotated, the shutter frame  335  and the OIS frame  400  moved in the optical axis direction with respect to the third rectilinear frame  130  (first frame body) via the third rectilinear frame  130  (first frame body). 
     Instead, the first and second frame bodies may be configured to be capable of relative rotation, and the second and third frame bodies may be configured to be incapable of relative rotation. In this case, the through-groove of the first frame body extends in the optical axis direction and the peripheral direction. 
     With this configuration, when the first frame body rotates, the second frame body (such as the shutter frame  335  and/or the OIS frame  400 ) and the retracting lens frame moved in the direction of the guide grove of the third frame body, such as the optical axis direction. Also, at this point the retracting lens frame  401  moves in a direction perpendicular to the optical axis, with respect to the second frame body. 
     Thus, even when the lens barrel  20  is configured so that the second frame body, such as the shutter frame  335  and/or the OIS frame  400 , moves in the optical axis direction with respect to the third frame body, the driven portion  411  and the guide groove a 7  can be provided, and the retracting lens frame  401  can be operated, just as in the above embodiment. This gives the same effect as above. 
     (H) In the above embodiment, an example was given in which the anti-rotation portion  511  of the OIS frame  400  was formed in a concave shape, and the upper face of the second contact portion  603 B of the retracting lens frame  401  came into contact with the recess  512 . Instead, as shown in  FIG. 24 , the second contact portion  603 B of the retracting lens frame  401  may come into contact with two side faces  512   a  of a recess  512 ′ of an anti-rotation portion  511 ′. In this case, the two side faces  512   a  of the recess  512 ′ are formed so as to move closer together toward the bottom  512   b  of the recess  512 ′. Consequently, the two side faces  512   a  of the recess  512 ′ are inclined and opposite each other. More specifically, the two side faces  512   a  of the recess  512 ′ are formed so as to move closer together toward the bottom  512   b  of the recess  512 ′. Consequently, the retracting lens frame  401  can be more reliably positioned with respect to the OIS frame  400 . 
     General Interpretation of Terms 
     In understanding the scope of the present disclosure, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, portions, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, portions, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including”, “having” and their derivatives. Also, the terms “part,” “section.” “portion,” “member” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts. Also as used herein to describe the above embodiment(s), the following directional terms “forward”, “rearward”, “above”, “downward”, “vertical”. “horizontal”, “below” and “transverse” as well as any other similar directional terms refer to those directions of the lens barrel. Accordingly, these terms, as utilized to describe the present technology should be interpreted relative to the lens barrel. 
     The term “configured” as used herein to describe a portion, section, or part of a device implies the existence of other unclaimed or unmentioned portions, sections, members or parts of the device to carry out a desired function. 
     The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. 
     While only selected embodiments have been chosen to illustrate the present technology, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the technology as defined in the appended claims. For example, the size, shape, location or orientation of the various portions can be changed as needed and/or desired. Components that are shown directly connected or contacting each other can have intermediate structures disposed between them. The functions of one element can be performed by two, and vice versa. The structures and functions of one embodiment can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature which is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further technologies by the applicant, including the structural and/or functional concepts embodied by such feature(s). Thus, the foregoing descriptions of the embodiments according to the present technologies are provided for illustration only, and not for the purpose of limiting the technology as defined by the appended claims and their equivalents. 
     INDUSTRIAL APPLICATION 
     The technology disclosed herein can be widely applied to lens barrels.