Abstract:
An imaging device comprises a lens barrel having an optical system with an adjustable focal point, and has a first state can focus relative to an imaging face, and a second state can not focus relative to the imaging face, a changing unit for changing the lens barrel from the second state to the first state when the imaging unit is activated, a discriminating unit which discriminates whether the state of the barrel is the first state or the second state, and a control unit which, at a time of activating the imaging unit, changes the lens barrel to the first state by the changing unit if it is discriminated that the state of the barrel is the second state, and which maintains the first state if it is discriminated that the state of the barrel is the first state.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. continuation application filed under 37 C.F.R. 1.53(b) claiming priority benefit of U.S. application Ser. No. 13/176,287, filed Jul. 5, 2011, pending, which claims foreign priority benefit on Japanese Patent Application No. 2010-152908, filed Jul. 5, 2010, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present invention relates to an imaging device and a lens barrel. 
         [0004]    2. Description of the Related Art 
         [0005]    In an imaging device of an interchangeable lens camera or the like, for example, in order to improve portability when the switch of the camera is set to off, there are cameras where the length of a mounted lens barrel is shortened as much as possible (for example, refer to Japanese Unexamined Patent Publication No. H8-43710). When the switch of such a camera is set to on, the lens extends from its shortest state to the photographing setup state. 
       SUMMARY 
       [0006]    However, because the camera is an interchangeable lens camera, a lens barrel which is not in its shortest state may be mounted on the camera. In this case, when the camera switch is set to on, the lens momentarily contracts and then extends to the photographing state, and this requires time for the startup. 
         [0007]    The objective of the present invention is to provide an imaging device and a lens barrel with good startup properties. 
         [0008]    The present invention solves the above problem by the following means. 
         [0009]    In order to achieve the object mentioned above, according to a first aspect of the present invention, an imaging device is provided. the imaging device comprise an imaging unit having an imaging face which images an image from a luminous flux, a lens barrel having an optical system with an adjustable focal point, and wherein a state of the barrel is changeable between a first state wherein it is possible to focus with respect to the imaging face by focal point adjustment of the optical system, and a second state wherein it is not possible to focus the image with respect to the imaging face, a changing unit for changing the lens barrel from the second state to the first state when the imaging unit is activated, a discriminating unit which discriminates whether the state of the lens barrel is the first state or the second state, and a control unit which, at a time of activating the imaging unit, changes the lens barrel to the first state by the changing unit if it is discriminated that the state of the lens barrel is the second state, and which maintains the first state if it is discriminated that the state of the lens barrel is the first state. 
         [0010]    The second state may be a state where a length of the lens barrel along an optical axis direction of the optical system is shorter than the first state. 
         [0011]    The second state may be a state wherein at least one part of the optical system has been moved to the imaging unit side compared to the first state, and the discriminating unit comprises a first detecting unit which detects that at least one portion of the optical system is at a control basis position of the optical system in the first state, and a second detecting unit which detects that the lens barrel is in the second state. 
         [0012]    The control unit may control the changing unit such that the optical system is detected to be at the control basis position by the first detecting unit if it is discriminated that the state of the lens barrel when the imaging unit is activated is the second state. 
         [0013]    The control unit may control the changing unit so that detection of the control basis position by the first detecting unit does not occur if it is discriminated that the state of the lens barrel when the imaging unit is activated is the first state. 
         [0014]    The imaging device may be further provided with a setting unit which can set whether or not the lens barrel is changed from the first state to the second state by the changing unit when the activation of the imaging unit is cancelled. 
         [0015]    The lens barrel may be separable from the imaging device, and may further comprise a second changing unit which changes the lens barrel to the second state when separated from the imaging device, if it is set by the setting unit to not change to the second state. 
         [0016]    The lens barrel may be mountable and dismountable from the imaging device, and the control unit may stop the changing of the state of the lens barrel by the changing unit until the lens barrel is completely mounted on the imaging device. 
         [0017]    The imaging device may further comprise a first mode where imaging by the imaging unit is possible, and a second mode where imaging by the imaging unit is not possible, and the control unit may stop the changing of the state of the lens barrel by the changing unit when in the second mode. 
         [0018]    In order to achieve the object mentioned above, according to a second aspect of the present invention, a lens barrel is provided. The lens barrel comprise an optical system with an adjustable focal point, a moving member which, by moving at least one part of the optical system, can change a state of the barrel between a first state where it is possible to focus with respect to an imaging face by focal point adjustment of the optical system, and a second state where is it not possible to focus an image with respect to the imaging face, and a discriminating unit which discriminates whether the state of the lens barrel is the first state or the second state. 
         [0019]    According to the present invention, it is possible to provide an imaging device and a lens barrel having good startup properties. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1A  is a perspective view conceptually showing a camera as a first embodiment of a camera system according to the present invention showing a state wherein the lens barrel is mounted on the camera; 
           [0021]      FIG. 1B  is a perspective view conceptually showing a state wherein the lens barrel is detached from the camera; 
           [0022]      FIG. 2  is a functional block drawing of the camera; 
           [0023]      FIG. 3A  is a cross sectional drawing of the lens barrel showing the shortened stored state; 
           [0024]      FIG. 3B  is a cross sectional drawing of the lens barrel; showing the photographing standby state; 
           [0025]      FIG. 4  is a chart drawing of the output signal of the lens state discrimination mechanism; 
           [0026]      FIG. 5  is a control flowchart for when the power switch is operated to OFF after concluding photography; 
           [0027]      FIG. 6  is a control flowchart for when the power switch is operated from OFF to ON; and 
           [0028]      FIG. 7  is a control flowchart for when a lens barrel is mounted, after power of the camera main body has been turned ON in a state where the lens barrel had not yet been mounted. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0029]    Below, an embodiment of the present invention will be explained with reference to the drawings and the like. Moreover, in each of the drawings mentioned below, for ease of explanation and understanding, a suitable XYZ Cartesian coordinate system is provided. In this coordinate system, the position of the camera when the photographer photographs an image in the landscape orientation making the optical axis OA horizontal, is referred to as the correct position. In this correct position, the direction going towards the left as seen from the photographer is the X plus direction, the direction going upwards is the Y plus direction, the direction going towards the photographic subject is the Z plus direction, and the direction going towards the image is the Z minus direction. 
         [0030]      FIG. 1  is a perspective drawing conceptually showing one embodiment of a camera system  1  according to the present invention, and  FIG. 1A  shows a state wherein the lens barrel  20  is mounted on the camera  10 , and  FIG. 1B  shows a state wherein the lens barrel  20  is detached from the camera  10 .  FIG. 2  is a functional block drawing of the camera system  1  of the present invention.  FIG. 3  is a cross sectional drawing showing an outline of the constitution of the lens barrel  20 , and  FIG. 3A  is the shortened stored state, and  FIG. 3B  is the extended photographing state.  FIG. 4  is chart drawing of the output signals of the lens state discrimination mechanism  60  provided in the lens barrel  20 . 
         [0031]    The camera system  1  is constituted of the interchangeable lens digital camera  10 , and a lens barrel  20  mountably and dismountably from the camera  10 . 
         [0032]    The camera  10  and the lens barrel  20 , from the separated state shown in  FIG. 1B , are aligned along the optical axis OA, and are joined so as to be mountable and dismountable by the mount mechanism  30  as shown in  FIG. 1A . In this way, the camera system  1  is capable of photographing with various lens barrels  20  having differing focal lengths, functions and the like mounted on the camera  10  according to the photographic subject. 
         [0033]    Further, the lens barrel  20  mounted on the camera  10  can adopt two states, i.e. a state which is compact and convenient for carrying (below this state is referred to as the shortened stored state) wherein a first lens unit L 1  is contracted into the fixed barrel  21  as shown by solid lines in  FIG. 1A ; and a state where photography is possible (below referred to as the extended photographing state) where the first lens unit L 1  is extended and projected outwards as shown by the double dotted line in  FIG. 1A . In the following explanation, a movement from the shortened stored state to the extended photographing state is called the extension movement, a movement from the extended photographing state to the shortened stored state is called the contraction movement, and both combined are called the extension and contraction movement. 
         [0034]    The mount mechanism  30  is an already known bayonet mount, and is constituted of a body mount  10 M provided at the camera  10 , and the lens mount  20 M provided at the lens barrel  20 . 
         [0035]    The body mount  10 M is provided with a body side contact  10 T, and the lens mount  20 M is provided with a lens side contact  20 T. The body side contact  10 T and the lens side contact  20 T are in conductive contact in a state wherein the body mount  10 M and the lens mount  20 M are joined, such that information exchange between the camera  10  and the lens barrel  20 , and power supply from the camera  10  to the lens barrel  20  are carried out. Further, by this conduction between the body side contact  10 T and the lens side contact  20 T, the later explained camera control device  40  (not shown in  FIG. 1 ; refer to  FIG. 2 ) can recognize when the lens barrel  20  is mounted. 
         [0036]    Below, each portion of the camera  10  is explained in order. 
         [0037]    The camera  10  is provided at its front face with the body mount  10 M and a detach button  11 . Further, the camera  10  is internally provided with an imaging element  12  and a camera control device  40  which generally controls the whole camera  1  (not shown in  FIG. 1 ; refer to  FIG. 2 ). Furthermore, the camera  10  is provided at its outer face with various operating members which constitute the operating portion  13  (refer to  FIG. 2 ) and is provided at its rear face with a display device  14 . 
         [0038]    The body mount  10 M, as mentioned above, is a constituent element of the camera  10  side of the mount mechanism  30 , and can be mountably and dismountably joined with the lens mount  20 M provided at the lens barrel  20 . 
         [0039]    The detach button  11  is disposed so as to be operable by pressing from the front face side of the camera  10 , and has the function of releasing the engagement between the body mount  10 M and the lens mount  20 M by the engaging mechanism, by a pressing operation. Further, the detach button  11  is linked with an electric barrel length contraction switch  15  (shown in  FIG. 2 ), and pressure information of the detach button  11  (namely, operating information of the barrel length contraction switch  15 ) is input to the camera control device  40 . Further, pressure (ON) information of the barrel length contraction switch  15  is used to command the contraction movement of the lens barrel  20 . 
         [0040]    The imaging element  12  is constituted of a CCD or the like which converts photographic subject light into an electric signal. The imaging element  12  is disposed inside the camera body  10  so that its light receiving face is at a right angle to the optical axis OA. The imaging element  12  is driven and controlled by the camera control device  40  and outputs electric image information converted from the subject light to the camera control device  40 . 
         [0041]    The operating portion  13  is provided with the power switch  13 A, the shutter button  13 B, and the mode selection dial  13 C. 
         [0042]    The power switch  13 A is the main switch which starts the flow of current to the camera body  10 . In the present embodiment shown in  FIG. 1 , it is disposed at the upper face of the camera  10 . 
         [0043]    The shutter button  13 B is a switch which commands a photographing operation to the camera control device  40 , and is disposed at the upper face of the camera  10 . 
         [0044]    The mode selection dial  13 C is a switch which changes the display of the display device  14  explained later. For example, it switches between the display (live view mode) of an image (through image) being imaged by the imaging element  12  at that time, and the reproduction display (reproduction mode) of an image (photographed image) photographed and recorded in a storage device, not shown. The mode selection dial  13 C is disposed at the upper face of the camera  10 . 
         [0045]    Further, the operating portion  13  may be provided with buttons or dials or the like, not shown, for carrying out various settings in addition to the above. Further, the operating manner and position of disposing each of the operating members of the operating portion  13  is not limited by the present embodiment, and may be set as appropriate. 
         [0046]    The display device  14  is constituted of a liquid crystal panel or the like, and displays the through image imaged by the imaging element  12 , a photographed image, and its histogram and photographic information, or the like. Further, it displays the setting information of the camera  1 , the setting menu or the setting items or the like. 
         [0047]    The camera control device  40 , not shown, is constituted by providing a CPU, buffer memory, a storage device storing various control programs, and the like. Further, the camera control device  40  is provided with a setting registration portion  41  which stores the settings relating to the control of the camera  1  freely set by the user. The setting registration portion  41 , for example, records as control information the setting (below referred to as the “barrel length contraction setting”) of “do/do not” put the lens barrel  20  mounted on the camera  10  into the shortened stored state when the power switch  13 A is set to OFF. 
         [0048]    The camera control device  40  generally controls the whole camera  1  including the lens barrel  20  based on the operation command input via the operating portion  13  and the control program stored in the storage device. The extension and contraction control of the lens barrel  20  by this camera control device  40  is explained below. 
         [0049]    The camera  10  constituted as described above is capable of photographing when the power switch  13 A is activated in a state where a lens barrel  20  is mounted as shown in  FIG. 1A  and the lens barrel  20  is in the extended photographing state. 
         [0050]    The camera  10  is controlled by the camera control device  40 , and when the shutter button  13 B is pressed and operated, the subject image imaged by the lens barrel  20  is converted by the imaging element  12  into an electric signal as image data, and this image data is signal processed as picture data and recorded in the recording device, not shown. 
         [0051]    The display device  14  displays a photographed image and its histogram and image information, as well as setting information, and setting menus and setting items and the like of the camera  1  according to the operation of the operating portion  13 , as described above. The display of a photographed image at the display device  14  is carried out by switching the mode selection dial  13 C of the operating portion  13  to the reproduction mode, as described above. 
         [0052]    Further, when the power switch  13 A of the camera  10  is in the ON state, when no operation of the operating portion  13  is carried out for a predetermined time, the camera control device  40  carries out a sleep control to stop the supply of power with the camera in its present state, and puts the camera into a sleep state. 
         [0053]    Next, the lens barrel  20  is explained. 
         [0054]    The lens barrel  20  is provided with three sets of lens units (the first lens unit L 1 , the second lens unit L 2 , and the third lens unit L 3 ), and is a zoom lens which is capable of changing its focal length (zooming). Further, the lens barrel  20 , as described above, is capable of adopting two states, a state (the shortened stored state) where the extending and contracting tube  23  (first lens unit L 1 ) is stored inside the exterior tube  21  shown in  FIG. 3A , and a state (the extended photographing state) where the extending and contracting tube  23  which holds the first lens unit L 1  protrudes from the front face side of the exterior tube  21  shown in  FIG. 3B . In the shortened stored state, the front face of the extending and contracting tube  23  approximately coincides with the front face of the exterior tube  21 . In the shortened stored state, it is not possible to photograph, and zooming is carried out in the extended photographing state. 
         [0055]    Below, each portion of the lens barrel  20  is explained in order. 
         [0056]    The lens barrel  20  is concentrically provided with the rotating tube  22 , the extending and contracting tube  23  which holds the first lens unit L 1 , and the fixed inner tube  24  inside the exterior tube  21 . Further, the lens barrel  20  is provided with the extension and contraction driving motor  25  and the lens control device  50  (not shown in  FIG. 3 , shown in  FIG. 2 ) which constitute the control board  26 , and the lens state discrimination mechanism  60  and the like. 
         [0057]    The exterior tube  21  is cylindrically shaped, and forms the exterior of the lens barrel  20 . The base end portion (end portion at the image side) of the exterior tube  21  is fixed to the rear face plate  27  constituting the lens mount  20 M. 
         [0058]    The rotating tube  22  is fit at the inner circumference of the exterior tube  21  so as to be freely rotatable, but immovable in the optical axis OA direction. A helical cam groove  22 A is formed at the inner circumferential face of the rotating tube  22 . A later described cam follower  23 B of the extending and contracting tube  23  is fit so as to be slidably moveable at this cam groove  22 A. 
         [0059]    Further, at the inner circumferential portion of the image side end portion of the rotating tube  22 , the inner circumferential gear  22 G is formed. This inner circumferential gear  22 G engages with the driving gear  25 G of the later described extension and contraction driving motor  25 . 
         [0060]    The extending and contracting tube  23  is formed with a cylindrical shape at its outer diameter which is slidably fit at the inner circumferential face of the rotating tube  22 , and the extending and contracting tube  23  holds the first lens unit L 1  via the cylindrically shaped retaining portion  23 A at its front face side inner circumference. 
         [0061]    The cam follower  23 B is provided to protrude at the outer circumferential face of the extending and contracting tube  23 , and this cam follower  23 B is slidably fit with the cam grove  22 A of the rotating tube  22 . 
         [0062]    Further, the direct advance groove  23 C is formed parallel to the optical axis OA at the inner circumference of the extending and contracting tube  23 . The later described direct advance guide projection  24 A of the fixed inner tube  24  is slidably fit at this direct advance groove  23 C. 
         [0063]    Furthermore, the projecting portion  61  constituting the lens state discrimination mechanism  60  is formed at the inner circumference of the extending and contracting tube  23 . The projecting portion  61  is a plate of a predetermined thickness, and extends towards the image side parallel to the optical axis OA direction from the retaining portion  23 A. The edge of the image side of the projecting portion  61  is the later described detection subject portion  61 A. The location of disposing this projecting portion  61  corresponds to the sensors  62  provided at the later described fixed inner tube  24  (first sensor  62 F, second sensor  62 R). 
         [0064]    The fixed inner tube  24  is fixed by its base end portion to the rear face plate  27 . The end portion of the front face side of the fixed inner tube  24  is drawn further in towards the image side than the front end face of the exterior tube  21 . 
         [0065]    Further, the direct advance guide projection  24 A is provided to protrude at the outer circumference side of the front end portion of the fixed inner tube  24 . The direct advance guide projection  24 A is slidably fit with the direct advance groove  23 C of the extending and contracting tube  23 . 
         [0066]    Furthermore, the fixed inner tube  24  is provided with a pair ( 2  units) of sensors  62  (a first sensor  62 F and a second sensor  62 R) constituting the lens state discrimination mechanism  60  along with the projecting portion  61  formed at the extending and contracting tube  23 . The first sensor  62 F is provided at the front end portion of the fixed inner tube  24 , and the second sensor  62 R is provided separated by a predetermined interval in the optical axis OA direction at the sensor side from the first sensor  62 F. 
         [0067]    The sensors  62  are photointerruptors formed of a light emitting portion and a light receiving portion disposed facing each other, and are disposed so as to detect the later described projecting portion  61  of the extending and contracting tube  23 . Namely, the output of the sensors  62  is OFF in a state where there is no occlusion in the detection region and the output is ON when the projecting portion  61  crosses the detection region. 
         [0068]    The lens state discrimination mechanism  60 , as described below, is constituted by the sensors  62  (first sensor  62 F, second sensor  62 R) provided at the fixed inner tube  24 , and the projecting portion  61  formed at the extending and contracting tube  23 . 
         [0069]    Here, the projecting portion  61  and the sensors  62  (first sensor  62 F, second sensor  62 R) are constituted with the below described positional relationship. 
         [0070]    In the shortened stored state shown in  FIG. 3A , the projecting portion  61  is positioned in the detection region of the first sensor  62 F, and further, the detection subject portion  61 A is positioned just in the detection region of the second sensor  62 R. This is the position where the output signal from the first sensor  62 F is ON, and in the case that the extending and contracting tube  23  (first lens unit L 1 ) has been moved from the extended photographing state towards the image side by a storing movement, the output signal of the second sensor  62 R switches from OFF to ON. Below, this signal state of the shortened stored state is called [ 1 , 1 ]. 
         [0071]    On the other hand, in an extension movement of the extending and contracting tube  23  (first lens unit L 1 ) from the shortened stored state, the projecting portion  61  continues to be positioned in the detection region of the first sensor  62 F, but the detection subject portion  61 A is outside of the detection region of the second senor  62 R. In this way, the output signal of the first sensor  62 F is ON, and the output signal of the second sensor  62 R is OFF. The signal state of this intermediate state is called [ 1 , 0 ]. 
         [0072]    In the extended photographing state shown in  FIG. 3B , the projecting portion  61  is outside of the detection region of the second sensor  62 R, and the detection subject portion  61 A is positioned just in the detection region of the first sensor  62 F. This is the position where, the output signal from the second sensor  62 R is OFF, and in the case that the extending and contracting tube  23  (first lens unit L 1 ) has been moved towards the front face side by the extension movement, the output signal of the first sensor  62 F switches from ON to OFF. The signal state of this extended photographing state is called [ 0 , 0 ]. 
         [0073]    By a constitution such as the above lens state discrimination mechanism  60 , it is possible to understand the extension and contraction state of the lens barrel  20 . Namely, as shown in  FIG. 4 , if the output signals of the first sensor  62 F and the second sensor  62 R are both ON (signal [ 1 , 1 ]), it is the shortened stored state, and if the output signals of the first sensor  62 F and the second sensor  62 R are both OFF (signal [ 0 , 0 ]), it is the extended photographing state. Further, if the output signal of the first sensor  62 F is ON and the output signal of the second sensor  62 R is OFF (signal [ 1 , 0 ]), it can be understood that the state is an intermediate state between the shortened stored state and the extended photographing state. 
         [0074]    The output signal of such a lens state discrimination mechanism  60  is input to the lens control device  50  as lens state detection information. 
         [0075]    The second lens unit L 2  and the third lens unit L 3  are provided so as to be moveable in the optical axis OA direction at the inner side of the fixed inner tube  24 . By moving the second lens unit L 2  and the third lens unit L 3  in the optical axis OA direction, the focal length of the lens barrel  20  changes (zooming). This zooming operation is carried out by a zoom drive mechanism, not shown, in response to an operation of the zoom switch  28  provided at the outer circumferential face of the exterior tube  21 . 
         [0076]    Further, the third lens unit L 3  is a focusing lens and can be independently moved and driven in the optical axis OA direction and the focus adjustment is carried out by changing the focal point by moving this third lens unit L 3  in the optical axis OA direction. 
         [0077]    The extension and contraction driving motor  25  is disposed at the image side (rear face plate  27  side) between the exterior tube  21  and the fixed inner tube  24 , with a rotation axis parallel to the optical axis OA. The driving gear  25 G is fixed to the rotation axis of the extension and contraction driving motor  25 , and the driving gear  25 G engages with the inner circumferential gear  22 G of the rotating tube  22 . In this way, the extension and contraction driving motor  25  rotationally drives the rotating tube  22  by its rotation. This extension and contraction driving motor  25  is driven and controlled by the below described lens control device  50 , and rotates in both the forward and reverse directions. Namely, this extension and contraction driving motor  25  rotationally drives the rotating tube  22  in both the forward and reverse directions. 
         [0078]    The control board  26  is disposed to be positioned adjoining the rear face plate  27  between the exterior tube  21  and the fixed inner tube  24 . The control board  26  constitutes the lens control device  50 , and the CPU and the like are mounted thereon. 
         [0079]    In the lens barrel  20  constituted as above, the extending and contracting tube  23 , because its direct advance groove  23 C is engaged with the direct advance guide projection  24 A of the fixed inner tube  24 , is not rotatable but is moveable in the extension direction (namely, the direction parallel to the optical axis OA) of the direct advance groove  23 C. Further, the cam follower  23 B of the extending and contracting tube  23  is slidably engaged with the cam groove  22 A of the rotating tube  22 . In this way, when the rotating tube  22  rotates, as the position in the optical axis OA direction of its cam groove  22 A changes, the cam follower  23 B of the extending and contracting tube  23  is movably operated in the optical axis direction OA. Namely, by the rotational driving of the rotating tube  22  by the extension and contraction driving motor  25 , the extending and contracting tube  23  is moved in the optical axis OA direction. The extension and contraction driving motor  25 , as described above, is controlled and driven by the lens control device  50 . Namely, the lens control device  50  controls the extension and contraction movement of the extending and contracting tube  23 . 
         [0080]    The lens control device  50  is connected so as to be able to exchange information with the camera control device  40  of the camera  10  via the lens mount  20 M (mount mechanism  30 ) when the lens barrel  20  is joined to the camera  10  by the mount mechanism  30 . Then, the lens control device  50  understands the extension and contraction state of the lens barrel  20  based on the input information from the lens state discrimination mechanism  60 , and sends this state information to the camera control device  40  of the camera  10 , and further, drives and controls the extension and contraction driving motor  25  based on the commands sent from the camera control device  40 . 
         [0081]    In the camera system  1  constituted of the camera  10  and the lens barrel  20  as described above, the camera control device  40  of the camera  10  carries out extension and contraction control of the lens barrel  20  via the lens control device  50  based on the operation of the operating portion  13 , the state information of the lens barrel  20  sent via the lens control device  50 , and a predetermined program. 
         [0082]    Next, the extension and contraction control of the lens barrel  20  by the camera control device  40  is explained with reference to the flow charts shown in  FIGS. 5 to 7 . In the following explanations and drawings, “step” is abbreviated as “S”. 
         [0083]    First, the control when the power switch  13 A is operated to OFF, after conclusion of the photography, shown in the flowchart of  FIG. 5 , is explained. 
         [0084]    When the photography is concluded, the lens barrel  20  is in the extended photographing state. When the power switch  13 A is set to OFF from this state, the camera control device  40  refers to the “barrel extension and contraction setting” of the setting registration portion  41 , and controls and drives the lens barrel  20  (extension and contraction driving motor  25 ) in response to this “barrel extension and contraction setting”. 
         [0085]    Namely, when the power switch  13 A is operated to OFF (S 01 ), it is judged whether the “barrel extension and contraction setting” is set to “contract barrel length when power is OFF” (S 02 ). 
         [0086]    In step  02 , if it is judged that the “barrel extension and contraction setting” is set to “contract barrel length when power is OFF” (Yes), then the extension and contraction driving motor  25  is driven towards the contraction movement side (S 03 ), and the point in time when the lens barrel  20  reaches the shortened stored state is judged (S 04 ). 
         [0087]    The judgment that the lens barrel  20  has reached the shortened stored state in this step  04  is carried out at the point in time that the signal [ 1 , 1 ] of the lens state discrimination mechanism  60  has been detected by the lens control device  50 . 
         [0088]    In step  04 , if it is judged that the lens barrel has reached the shortened stored state (Yes), the storing movement (driving of the extension and contraction driving motor  25 ) is stopped (S 05 ). In this way, the lens barrel  20  reaches the shortened stored state, and the power is set to OFF (S 06 ). 
         [0089]    On the other hand, in step  02 , if the “barrel extension and contraction setting” is set to “do not contract barrel length when power is OFF” (No), the power is set to OFF with only the barrel length contraction switch  15  being effective(S 07 ), without driving the extension and contraction driving motor  25  (with the lens barrel as is, in the extended photographing state), and the ON operation of the barrel length contraction switch  15  is judged (namely, the pressing operation of the detach button  11 ) (S 08 ). 
         [0090]    Then, if it is judged in step  08  that the barrel length contraction switch  15  is operated to ON (Yes), each step of the storing movement after step  03  is executed, and the power is set to OFF as in the shortened stored state (S 06 ). 
         [0091]    According to the control when the power switch  13 A is OFF as described above, is it possible to set the power to OFF with the lens barrel as is, in the extended photographing state, by setting the “barrel extension and contraction setting” of the setting registration portion  41  to “do not contract barrel length when power is OFF”. In this way, the next time the power is set to ON, it is unnecessary to carry out the extension movement of the lens barrel  20  from the shortened stored state to the extended photographing state. 
         [0092]    Namely, if the lens control device  50  detects a signal [ 0 , 0 ] of the lens state discrimination mechanism  60  the extended photographing state, it is possible to immediately carry out the control after the recognition of the extended photographing state, without carrying out the initial operation for understanding the position by moving the lens barrel  20  to a temporary predetermined state. Because of this, it is possible to photograph in a very short time by setting the power switch  13 A to ON, and it is possible to avoid the problem that a shutter chance is missed due to the initialization operation. 
         [0093]    Further, in the power OFF state with the lens barrel  20  in the extended photographing state, if the barrel length contraction switch  15  is pressed and operated, the contraction movement is carried out. Because of this, even if the “barrel extension and contraction setting” is set to “do not contract barrel length when power is OFF”, it is possible to optionally put the lens barrel  20  in the shortened stored state after the power is OFF. 
         [0094]    Next, the control when the power switch  13 A is operated from OFF to ON is shown in the flowchart of  FIG. 6  is explained. 
         [0095]    When the power switch  13 A is operated to ON (S 11 ), it is judged whether the lens barrel  20  is in the shortened stored state (whether the lens control device  50  detects a signal [ 1 , 1 ] of the lens state discrimination mechanism  60 ) (S 12 ). 
         [0096]    In step  12 , if it is judged that the lens barrel  20  is in the shortened stored state (Yes), the extension and contraction driving motor  25  is driven in an extension movement (S 13 ), and the point in time when the lens barrel  20  reaches the extended photographing state is judged (S 14 ). 
         [0097]    The judgment that the lens barrel  20  has reached the extended photographing state is carried out at the point in time that the signal [ 0 , 0 ] of the lens state discrimination mechanism  60  has been detected by the lens control device  50 . 
         [0098]    In step  14 , when it is judged that the lens barrel  20  has reached the extended photographing state (Yes), the extension movement (driving of the extension and contraction driving motor  25 ) is stopped (S 15 ). In this way, the lens barrel  20  reaches the extended photographing state. 
         [0099]    On the other hand, in step  12 , if it is judged that the lens barrel  20  is not in the shortened stored state (No), it is next judged whether the lens barrel  20  is in an intermediate state (S 16 ). 
         [0100]    The judgment that the lens barrel  20  is in an intermediate state is carried out if the lens control device  50  detects that the signal of the lens state discrimination mechanism  60  is [ 1 , 0 ]. 
         [0101]    In step  16 , if it is judged that the lens barrel  20  is in an intermediate state (Yes), the above described steps  13  to  15  are executed, and the lens barrel  20  reaches the extended photographing state. 
         [0102]    In step  16 , if it is judged that the lens barrel  20  is not in an intermediate state (No), the lens barrel is in the extended photographing state (namely, the state where the lens control device  50  detects the signal [ 0 , 0 ] from the lens state discrimination mechanism  60 ), or the lens barrel  20  is not mounted, and the control is concluded. 
         [0103]    In the control described above, when the power switch  13 A is turned ON, in whatever state the lens barrel  20  is at that time, it is put into the extended photographing state. 
         [0104]    Namely, according to the control at the time that the power switch  13 A is turned OFF shown in the flowchart in the above described  FIG. 5 , in the state that the power of the camera  1  (camera  10 ) is turned OFF, the lens barrel  20  has the two states of the shortened stored state and the extended photographing state, and in addition, it is possible that mounting or dismounting of the lens barrel  20  is carried out in a state of power OFF, and the lens barrel  20  is mounted in an intermediate state. 
         [0105]    According to the control when the power switch  13 A is ON in the present invention, in any of these states, the lens barrel  20  is put in the extended photographing state as the power switch  13 A is turned ON. 
         [0106]    Next, the control for the case that the lens barrel  20  is mounted, after the power of the camera  10  is turned ON in a state that the lens barrel  20  has not been mounted, shown in the flowchart of  FIG. 7 , is explained. 
         [0107]    When the lens barrel  20  is mounted (S 21 ) with the power of the camera  10  in the ON state, first, it is judged whether the state of the camera  10  is the photographing mode (S 22 ). 
         [0108]    In step  22 , if it is judged that the state of the camera  10  is not the photographing mode (No), control is concluded as being in the reproduction mode. 
         [0109]    On the other hand, in step  22 , if it is judged that the state of the camera  10  is the photographing mode (Yes), next, it is judged whether the mounted lens barrel  20  is in the extended photographing state (S 23 ). 
         [0110]    In step  23 , if it is judged that the lens barrel  20  is in the extended photographing state (Yes), the control is concluded as is. 
         [0111]    In step  23 , if it is judged that the lens barrel  20  is not in the extended photographing state (No), next, it is judged whether the lens barrel  20  is in an intermediate state (S 24 ). 
         [0112]    In step  24 , if it is judged that the lens barrel  20  is not in an intermediate state (No), the camera  10  is put into a sleep state (S 25 ) and the control is concluded. 
         [0113]    In step  24 , if it is judged that the lens barrel  20  is in an intermediate state (Yes), a warning display “lens barrel  20  is mounted in an intermediate state” is displayed at the display device  14  (S 26 ) and the control is concluded. 
         [0114]    In the above described control, in a camera  10  in the photographing mode with the power in the ON state, if a lens barrel  20  is mounted in the shortened stored state, the camera  10  is put in the sleep state. Further, if the lens barrel  20  is mounted in an intermediate state, a warning is displayed. In this way, it is possible to prevent problems due to extending the lens barrel  20  just as the lens barrel  20  is mounted on the camera  10 . 
         [0115]    With the camera  10  in the sleep state, the sleep state is cancelled by operating any of the operating members of the operating portion  13 . When the sleep state is cancelled, control is carried out in the same way as when the power is ON shown in the flowchart of  FIG. 6  described above, and the lens barrel  20  is put in the extended photographing state. 
         [0116]    Further, in the case that a warning display is made when the lens barrel  20  is mounted on the camera  10  in an intermediate state, by turning the power switch  13 A OFF once, and then turning it ON again, the above described control for when the power is ON shown in the flowchart in  FIG. 6  is carried out, and the lens barrel  20  is put in the extended photographing state. 
         [0117]    Further, when the camera  10  is in the reproduction mode, in the above control, the lens barrel  20  is not moved regardless of its state. In this case, by switching the mode selection dial  13 C to the photographing mode, control is carried out in the same as when the power is ON as described above, and the lens is put in the extended photographing state. 
         [0118]    According to the above described embodiment, the following effects are obtained. 
         [0119]    (1) The lens barrel  20  of the above described camera  1  can adopt the different states of the shortened stored state and the extended photographing state. The lens barrel  20  is provided with a lens state discrimination mechanism  60 , which is constituted with two sensors  62  (first sensor  62 F and second sensor  62 R), and a projecting portion  61  which is detected by these sensors  62 , and which have different combinations of output signals from the sensors  62  when the lens barrel  20  is in the shortened stored state and in the extended photographing state. In this way, it is possible to recognize the state of the lens barrel  20  by the output signal of the lens state discrimination mechanism  60 , and based on this subsequent control is possible. 
         [0120]    (2) According to the control by the camera control device  40  when the power switch  13 A is operated to OFF, it is possible to switch the power to OFF with the lens barrel  20  as is, in the extended photographing state, by setting the “barrel extension and contraction setting” of the setting registration portion  41  of the camera control device  40  to “do not contract barrel length when power is OFF”. In this way, the next time the power is switched ON, it is possible to photograph immediately without carrying out the extension movement of the lens barrel  20 , and it is possible to avoid the problem of missing a shutter chance because of the initialization operation. 
         [0121]    (3) According to the control carried out by the camera control device  40  when the power switch  13 A is operated to OFF, if the detach button  11  is pressed and operated in the state where the power is OFF with the lens barrel  20  in the extended photographing state, the contraction movement is carried out. Because of this, even if the “barrel extension and contraction setting” is set to “do not contract barrel length when power is OFF”, it is possible to voluntarily set the lens barrel  20  to the shortened stored state after the power is OFF. Further, when the detach button  11  is pressed and operated in order to change the lens, a storing movement of the lens barrel  20  is carried out and it is put in the shortened stored state. In this way, lens barrels  20  in a single state separated from the camera  10  are uniformly put into the compact shortened stored state. 
         [0122]    (4) According to the control by the camera control device  40  when the power switch  13 A is operated to ON, when the power switch is switched to ON, it is possible to put the lens barrel  20  in the extended photographing state, regardless of which state, the shortened stored state, an intermediate state, or the like, it is in at that time. 
         [0123]    (5) According to the control by the camera control device  40  in the case that a lens barrel  20  is mounted, after the power of the camera  10  has been switched to ON in a state where the lens barrel  20  has not yet been mounted, in the case that the lens barrel is mounted in the shortened stored state on the camera  10  in the photographing mode with the power in the ON state, the camera  10  is put in the sleep state. Further, in the case that the lens barrel  20  is mounted in an intermediate state, a warning display is carried out. In this way, it is possible to prevent problems with the lens barrel  20  extending just as the lens barrel  20  is being mounted on the camera  10 . 
         [0124]    (Modifications) 
         [0125]    The above explained embodiments are not limitations, and many modifications and changes are possible such as those shown below, and these are also included in the scope of the present invention. 
         [0126]    (1) In the present embodiment, it was explained that the extension and contraction control of the lens barrel  20  is carried out by the camera control device  40  provided at the camera  10 , based on the lens state information input from the lens control device  50 . However, it may also be constituted so as to be carried out by the camera control device  40  from understanding the lens state information, and further, it may also be constituted such that the extension and contraction control of the lens barrel  20  is carried out by the lens control device  50 . Moreover, it may also be constituted such that the control is appropriately shared by the camera control device  40  and the lens control device  50 . 
         [0127]    (2) In the present embodiment, the sensors  62  (first sensor  62 F and second sensor  62 R) of the lens state judging means  60  are constituted of photo interruptors. However, the detection means is not limited to this, and may be any other means capable of detection. 
         [0128]    (3) The present embodiment is constituted such that the detach button  11  and the barrel length contraction switch  15  are linked. However, the barrel length contraction switch  15  may also be independently provided. 
         [0129]    Moreover, the embodiments and modifications may be used in appropriate combinations, but detailed explanations thereof are omitted. Further, the present invention is not limited by the above explained embodiments.