JP2011022280A - Division type lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a division type lens barrel in which focusing at a minute level is easy and a manual adjustment to make a diaphragm value an arbitrary value is easy even when the entire length of the lens barrel is long. <P>SOLUTION: An extension tube 20 includes: a lens barrel side barrel part 21 which can be attached and detached to and from a lens barrel part 60; a moving barrel part 24 which can be slid with respect to the lens barrel side barrel part; straight advancing guide mechanisms 25 and 26 which are formed between the lens barrel side barrel part and the moving barrel part; a male screw groove 29 which is formed in the moving barrel part; and an operation means 30 which is not moved in an optical axis direction, but can be rotated around an optical axis, with respect to the lens barrel side barrel part and has a female screw groove 31 screwed on the male screw groove. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a split lens barrel.

Since the lens barrel of the super telephoto lens has a long lens barrel length and a large overall weight, if such a lens barrel is manufactured as an inseparable integral, it is inconvenient to carry when not photographing. Therefore, after dividing such a long lens barrel into a plurality of detachable cylindrical members, a moving lens group (focus lens group) and a moving mechanism for moving the moving lens group to the front cylindrical member, If a focus ring for operating the moving mechanism is provided and the rear cylindrical member is a so-called extension tube (a cylindrical member not incorporating a photographing lens), the lens barrel can be easily carried when not photographing. .
The split-type lens barrel having such a structure can perform telephoto shooting with manual focus by manually operating a focus ring provided on a front cylinder member while observing a subject. If the rear cylinder member is provided with signal transmission means for transmitting signals between the camera body side and the front cylinder member, AF (autofocus) operation and aperture adjustment operation on the camera body side are possible. become.

JP-A-7-230116

However, when the lens barrel is configured as a split type, the following problems occur.
That is, although high focus accuracy is required for astronomical photography or the like, generally, it is not easy to perform focus adjustment at a minute level by a focus ring, and there is a possibility that astronomical photography cannot be performed accurately.
Furthermore, it has been difficult to adjust the aperture value to an arbitrary (desired) value.

  The present invention provides a split-type lens barrel that is easy to focus at a minute level and can be easily adjusted to an arbitrary aperture value manually even when the total length of the lens barrel is long. The purpose is to provide.

  The extension tube of the split-type lens barrel of the present invention can be attached to and detached from the lens barrel portion including a movable lens group and an adjustment ring for adjusting the optical axis direction position of the movable lens group. A split-type lens barrel having an extension tube that does not incorporate a lens group, wherein the extension tube is attachable to and detachable from the lens barrel, and the lens barrel side cylinder Separately, a movable cylinder part that is movable relative to the barrel side cylinder part in the optical axis direction, a rectilinear guide mechanism formed between the barrel side cylinder part and the movable cylinder part, and the barrel A male screw groove centered on the optical axis formed on one outer peripheral surface of the side tube portion and the moving tube portion, and immovable in the optical axis direction with respect to the other of the lens tube side tube portion and the moving tube portion And a female screw groove that can rotate about the optical axis and is screwed into the male screw groove. A rotary member having, the rotary member is characterized by comprising an operation means for rotating the above optical axis.

  It is preferable that the operating means also serves as the rotating member.

  The operation means is a slide adjustment knob that is rotatable about a rotation axis extending in a radial direction of the extension tube and supports a first bevel gear centered on the rotation axis, and the rotation member is the first cap A second bevel gear that meshes with the gear and whose rotation axis extends in a direction parallel to the optical axis may be used.

  An urging means for urging both in the direction away from each other may be provided between the barrel-side cylinder part and the movable cylinder part.

  The lens barrel includes an aperture mechanism, and the extension tube is linked to the aperture mechanism when connected to the lens barrel, and opens and closes by rotating around the optical axis of the photographing lens group. A power transmission lever, a diaphragm adjusting member provided rotatably on the outer peripheral surface, and an operation force transmission for transmitting the rotational force of the diaphragm adjusting member to the power transmission lever and rotating the power transmission lever around the optical axis. And a mechanism.

  The diaphragm adjustment member is a diaphragm adjustment knob that can rotate about a rotation axis extending in a radial direction of the extension tube, and the operation force transmission mechanism rotates the rotation force of the diaphragm adjustment knob around the optical axis. You may have the cam mechanism converted into directional force.

  The aperture adjustment member may be a ring member that can rotate about the optical axis, and the operating force transmission mechanism may be a connecting member that links the ring member and the power transmission lever so as to rotate together. Good.

  According to the present invention, since the moving cylinder portion is moved by the screw mechanism, it is possible to easily adjust the movement of the moving cylinder portion at a minute level, and to easily perform fine focusing of the lens barrel. Can do.

1 is a side view showing a cross-sectional view of a part of a digital camera including a split lens barrel according to an embodiment of the present invention. It is an expansion vertical side view of the upper half part of an extension tube. It is an expansion vertical side view of the lower half part of an extension tube. It is a bottom view of a rotation lever and a cam mechanism when a set aperture value is maximum (open aperture). It is sectional drawing seen from back when it cut | disconnects by the VV arrow line of FIG. 2 when a setting aperture value is the maximum. It is a bottom view of a rotation lever and a cam mechanism when a set aperture value is minimum (minimum aperture). It is sectional drawing similar to FIG. 5 when a setting aperture value is the minimum. It is a bottom view of an aperture adjustment knob. FIG. 4 is an enlarged vertical side view similar to FIG. 2 of a modified example in which an aperture adjustment knob, a cam mechanism, a rotation lever and the like are omitted.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The direction in the following description is based on the arrow in the figure.
The digital camera 10 to which the present invention is applied is a telephoto camera suitable for astronomical observation or the like. The digital camera 10 includes an imaging device, a rotating mirror, a shutter, an image processing device, a finder, a shutter button, a control device (for controlling operations of the imaging device, the rotating mirror, the shutter, the image processing device, and the like) A camera body 11 having a contact pin to be electrically connected, an internal power source (which supplies power to an image sensor, an image processing device, a control device, etc.), and a split lens that can be attached to and detached from the front opening of the camera body 11 The lens barrel 15 is provided.

The split lens barrel 15 includes an extension tube 20 and a barrel portion 60 that are detachable from each other.
The extension tube 20 includes a cylindrical barrel-side cylinder portion 21 that is open at both front and rear ends, and a movable cylinder portion 24 that is positioned coaxially immediately after the barrel-side cylinder portion 21. At the front end portion of the lens barrel side cylinder portion 21, a mount portion 62 formed at the rear end portion of the lens barrel portion 60 and a detachable mount portion 22 are formed, and the outer periphery of the front end portion of the lens barrel side cylinder portion 21 is formed. The surface is provided with a lock ring 23 having a female thread groove on the inner peripheral surface so as to be rotatable and slidable (see FIG. 1, not shown in FIGS. 2 and 3). A mounting portion (not shown) that can be attached to and detached from the mounting portion formed at the front opening of the camera body 11 is formed at the rear end portion of the moving cylinder portion 24.
As shown in FIGS. 2 and 3, the front part of the movable cylinder part 24 is thinner than the rear part, the outer diameter thereof is smaller than the outer diameter of the rear part, and three linear guides extending in the optical axis direction on the outer peripheral surface thereof. Grooves 25 are recessed at 120 ° intervals in the circumferential direction. On the other hand, three rectilinear guide keys 26 are fixed by screws at 120 ° intervals in the circumferential direction at three locations on the inner peripheral surface of the rear end portion of the barrel-side cylinder portion 21. The three rectilinear guide keys 26 are slidably engaged with the corresponding rectilinear guide grooves 25. Since the rectilinear guide groove 25 and the rectilinear guide key 26 are equal in width and the longitudinal length of the rectilinear guide key 26 is shorter than that of the rectilinear guide groove 25, the movable cylinder portion 24 is moved by the rectilinear guide mechanism including the rectilinear guide groove 25 and the rectilinear guide key 26. It is slidable in the front-rear direction with respect to the barrel-side cylinder portion 21 and cannot rotate about the optical axis. Further, the moving cylinder portion 24 is an annular member centered on the optical axis, and a male screw ring 28 having a male screw groove 29 on the outer peripheral surface thereof is integrated by a screw (the male screw ring 28 is a part of the moving cylinder portion 24). Part). On the other hand, on the outer peripheral surface of the rear part of the barrel-side cylinder part 21, a slide adjustment ring (operation means) comprising two members that can rotate around the optical axis with respect to the barrel-side cylinder part 21 and cannot slide in the optical axis direction. A (rotating member) 30 is provided, and an internal thread groove 31 that engages with the external thread groove 29 is formed on the inner peripheral surface of the slide adjustment ring 30. Further, as shown in FIG. 3, between the rear end surface of the barrel-side cylinder portion 21 and the movable barrel portion 24, the movable barrel portion 24 is urged rearward with respect to the barrel-side barrel portion 21, thereby A compression coil spring (biasing means) 32 for removing backlash between the groove 29 and the female thread groove 31 is provided. Therefore, when the slide adjustment ring 30 is rotated with respect to the barrel-side cylinder portion 21, the movable cylinder is brought about by the screwing relationship between the male screw groove 29 and the female screw groove 31 and the straight guide relationship between the straight guide groove 25 and the straight guide key 26. The portion 24 slides relative to the lens barrel side tube portion 21 in the optical axis direction (front-rear direction).

In the vicinity of the front end portion of the inner peripheral surface of the barrel-side tube portion 21, an annular inner flange 33 that projects toward the inner periphery is provided integrally. As shown in FIGS. 2, 3, 5, and 7, an annular rotating ring 34 having an inner diameter larger than the inner flange 33 and substantially the same outer diameter is located on the rear surface of the inner flange 33. As shown in the figure, the rotating ring 34 has three elongated holes 35 extending in the same direction as the circumferential direction of the rotating ring 34 at intervals of 120 ° in the circumferential direction. Further, the screw portions formed at the front end portions of the three screws 36 inserted through the long holes 35 from the rear of the rotating ring 34 are respectively screwed into the three screw holes 37 formed on the rear surface of the inner flange 33. (See FIG. 3) An annular flange portion 36 a of a screw 36 having a diameter larger than the width of the long hole 35 is in contact with the rear surface of the rotating ring 34. Therefore, the rotary ring 34 can rotate relative to the inner flange 33 within a rotation angle regulated by the long hole 35 and the screw 36. Further, as shown in FIGS. 5 and 7, since both ends of the two tension springs S are fixed between the two screws 36 and the two positions on the rear surface of the rotating ring 34, the rotating ring 34 has two The tension spring S is urged to rotate counterclockwise (clockwise in FIGS. 5 and 7) in front view. As shown in FIG. 2, a power transmission lever 38 extending forward is fixed to the upper part of the front surface of the rotating ring 34. The power transmission lever 38 is a light drilled as a through hole in the inner flange 33. An arc hole 39 centering on the axis A is passed forward.
At a position corresponding to the power transmission lever 38 on the rear surface of the rotating ring 34, a fixing piece 41 extending in the radial direction of the extension tube 20 formed at the front end portion of the rotating lever 40 having an L shape in side view is provided with two screws. It is fixed by.

  A pedestal 43, which is a low-profile columnar member, is fixed to the upper end portion of the outer peripheral surface of the lens barrel side tube portion 21, and a diaphragm which is a substantially cylindrical member having a larger diameter than the pedestal 43 is provided above the pedestal 43. An adjustment knob (a diaphragm adjustment member) 45 is covered. A concave portion that fits into the upper portion of the pedestal 43 is formed on the lower surface of the diaphragm adjustment knob 45, and a fixing concave portion 45a having a cylindrical shape is formed upward on the bottom surface of the concave portion. The upper part of the rotating shaft 46 having a cylindrical shape is fitted and fixed. And the lower half part of the rotating shaft 46 fits in a through hole formed in the central part of the pedestal 43 and a through hole formed in the upper part of the lens barrel side cylinder part 21 and communicating with the through hole. Therefore, the aperture adjustment knob 45 is rotatable relative to the lens barrel side cylinder portion 21 and the pedestal 43 around the rotation shaft 46. Further, a ball support hole 44 that penetrates the pedestal 43 in the thickness direction is formed at a position shifted from the center of the pedestal 43 to the outer peripheral side, and is coaxial with the ball support hole 44 inside the ball support hole 44. A compression coil spring 47 is inserted. The lower surface of the compression coil spring 47 is in contact with the upper surface of the barrel-side cylinder portion 21, and a click ball 48 having substantially the same diameter as the ball support hole 44 is supported on the upper end of the compression coil spring 47. On the other hand, seven click grooves 49 having substantially the same diameter as the click ball 48 are formed in the circumferential direction on the bottom surface of the concave portion of the aperture adjustment knob 45 (see FIG. 8), and urged upward by the compression coil spring 47. The upper half of the click ball 48 engaged is engaged with any click groove 49. Accordingly, when the aperture adjustment knob 45 is rotated with respect to the lens barrel side cylinder portion 21 and the pedestal 43, the upper half of the click ball 48 engaged with any one of the click grooves 49 escapes from the click groove 49. Since the click ball 49 and the click groove 49 are engaged with each other, the click feeling is obtained.

  A retaining member 50 located on the inner peripheral side of the lens barrel side tube portion 21 is fixed to the lower surface of the rotating shaft 46, and the retaining member 50 allows the rotating shaft 46 to penetrate the lens barrel side tube portion 21 and the pedestal 43. It is prevented from coming out from the hole to the outer peripheral side. As shown in FIGS. 4 and 6, the retaining member 50 includes a large-diameter semicircular portion 51 and a small-diameter semicircular portion 52 that is smaller than the large-diameter semicircular portion 51, and two stopper surfaces on the outer peripheral surface thereof. 53 and 54 are provided. On the other hand, a stopper pin 58 that protrudes toward the inner peripheral side (optical axis A side) is provided on the inner peripheral surface of the lens barrel side tube portion 21 up to the same radial position as the retaining member 50. Therefore, when the diaphragm adjustment knob 45 is rotated counterclockwise in plan view, the retaining member 50 can be rotated to a position where the stopper surface 53 contacts the stopper pin 58, and the diaphragm adjustment knob 45 is rotated clockwise in plan view. When rotated, the stopper surface 54 can be rotated to a position where it comes into contact with the stopper pin 58. Thus, when the compression coil spring 47 rotates, the stopper pin 58 is always located on the outer peripheral side of the small-diameter semicircular portion 52, so that the stopper pin 58 and the small-diameter semicircular portion 52 do not contact each other. Further, when the stopper pin 58 comes into contact with the stopper surface 53, the upper half of the click ball 48 is engaged with the click groove 49 located at one end of the seven click grooves 49 arranged in the circumferential direction, and the stopper pin 58 is When contacting the stopper surface 54, the upper half of the click ball 48 engages with the click groove 49 located at the other end.

Further, as shown in FIGS. 4 and 6, a cam member 55 is fixed to the bottom surface of the retaining member 50 in a state of being eccentric with respect to the large-diameter semicircle portion 51 and the small-diameter semicircle portion 52. The cam member 55 has a semicircular shape as shown in the figure, and its arc surface forms a cam surface 56. As shown in FIGS. 2, 4, and 6, the radial positions (of the extension tube 20) of the cam member 55 and the rear portion of the rotary lever 40 coincide with each other, and the two tension springs S are used as described above. Since the rotating ring 34 is urged to rotate counterclockwise when viewed from the front, one side surface (left side when viewed from the front) of the rear portion of the rotating lever 40 integrated with the rotating ring 34 is always the cam of the cam member 55. Contact surface 56. As shown in FIGS. 4 and 6, when viewed in the axial direction of the rotation shaft 46 (the radial direction of the extension tube 20), the linear distance from the center point of the rotation shaft 46 to the cam surface 56 is the position of each cam surface 56. It depends on. Therefore, if the contact position of the cam surface 56 with respect to the side surface of the rotation lever 40 is gradually changed by rotating the aperture adjustment knob 45, the rotation direction position around the optical axis A of the rotation lever 40 and the rotation ring 34 is changed by the cam surface 56. Change gradually. Specifically, when the aperture adjustment knob 45 is rotated clockwise in plan view, the rotary lever 40 and the rotary ring 34 rotate clockwise in front view, so that the power transmission lever 38 is located inside the arc hole 39. Rotate clockwise in front view. On the other hand, when the iris adjustment knob 45 is rotated counterclockwise in plan view, the rotary lever 40 and the rotary ring 34 rotate counterclockwise in front view, so that the power transmission lever 38 moves inside the arc hole 39. Rotates counterclockwise in front view.
Among the members described above, the rotating ring 34, the rotating lever 40, the rotating shaft 46, the retaining member 50, and the cam member 55 are components of the operating force transmission mechanism, and the rotating lever 40 and the cam member 55 are components of the cam mechanism. It is.

The lens barrel portion 60 includes a cylindrical fixed ring 61 that is open at both front and rear ends. At the rear end portion of the fixed ring 61, a mount portion 62 that is detachable from the mount portion 22 of the lens barrel side tube portion 21 and is detachable from the mount portion formed in the front opening of the camera body 11, is formed. A male screw groove (not shown) that can be screwed into the female screw groove of the lock ring 23 is formed on the outer peripheral surface of the mount portion 62.
In the vicinity of the rear end of the inner peripheral surface of the fixed ring 61, an inner flange 63, which is an annular body centering on the axis of the fixed ring 61, projects integrally toward the inner peripheral side. A third group support ring 64 that supports the third lens group L3 including two lenses is fixed to the inner flange 63.
Further, the rear end portion of the linear guide ring 65 located on the inner peripheral side of the fixed ring 61 is fixed to the inner flange 63. In the rectilinear guide ring 65, three rectilinear guide grooves 66 (only one is shown in FIG. 1) extending in the direction of the optical axis A are formed as through grooves at intervals of 120 ° in the circumferential direction. In each of the rectilinear guide grooves 66 of the rectilinear guide ring 65, an outer peripheral surface of a second group support ring 67 that is located on the inner peripheral side of the rectilinear guide ring 65 and supports the second lens group L2 including two lenses is provided. Three cam followers 68 projecting at intervals of 120 ° are fitted so as to be relatively movable. Further, between the front end portion of the fixed ring 61 and the front end portion of the linear guide ring 65, a focus ring (adjustment ring) 70 that is an annular member having substantially the same diameter as the fixed ring 61 is provided in the second lens group L2 and the third lens. It is supported so that it can rotate around the optical axis A of the group L3 and cannot slide in the optical axis A direction. A cam ring 71, which is an annular member having a smaller diameter than the focus ring 70, is fixed to the inner peripheral surface of the focus ring 70, and a cam groove 72 inclined with respect to the rectilinear guide groove 66 is 120 in the circumferential direction. Three are formed at intervals (only one is shown in FIG. 1). Since each cam groove 72 is fitted with a cam follower 68 penetrating the corresponding linear guide groove 66 so as to be relatively movable, when the focus ring 70 is rotated around the optical axis A, the second group support ring 67 and the first support ring 67 are arranged. The two lens unit L2 moves forward and backward along the optical axis A.
As described above, the second lens group L2 and the second group support ring 67 can be advanced and retracted by manual operation of the focus ring 70. However, the lens barrel 60 is provided with a motor (not shown) and the power of the motor. A power transmission mechanism for transmitting to the cam ring 71, a circuit board 74 for controlling the motor, a flexible printed circuit board (wiring) 75 extending rearward from the circuit board 74, and a rear end portion of the flexible printed circuit board (wiring) 75 are provided. Contact pins 76 are provided.
Further, a front fixed ring 77 (only the rear end portion is shown in FIG. 1) is fixed to the front end portion of the straight guide ring 65, and the front peripheral portion of the front end portion (not shown) of the front side fixed ring 77 has an inner peripheral surface. A first lens group (not shown) composed of two lenses is fixed.

  Further, an aperture mechanism 80 located between the second lens group L2 and the third lens group L3 is provided inside the fixed ring 61. The aperture mechanism 80 is arranged in the circumferential direction around the axis of the fixed ring 61 (the optical axes A of the first lens group, the second lens group L2, and the third lens group L3) and can rotate about its own rotation axis. A plurality of aperture blades (not shown) are provided. Further, each of these diaphragm blades is urged to rotate in the minimum diaphragm direction by urging means (not shown). A diaphragm operating lever 81 that is rotatable in the circumferential direction around the axis of the fixed ring 61 is provided inside the fixed ring 61. The front end of the diaphragm operating lever 81 is linked to the diaphragm mechanism 80, the rear end of the diaphragm operating lever 81 passes through the third group support ring 64 in a rotatable manner, and the rear end of the diaphragm operating lever 81 is upward. The engagement / disengagement part 82 is bent toward the front.

The extension tube 20 can be connected to the camera body 11 by engaging the mount portion formed at the front opening of the camera body 11 while rotating the mount portion at the rear end about the optical axis A, and the extension tube 20 can be connected to the extension tube 20. It can be removed from the mount portion of the camera body 11 by rotating in the direction opposite to the rotation direction.
In order to connect the lens barrel portion 60 to the extension tube 20, the mount portion 22 of the extension tube 20 and the mount portion 62 of the fixed ring 61 are engaged while rotating, and the lock ring 23 is rotated to lock the lock ring 23. The female screw groove is screwed into the male screw groove formed on the outer peripheral surface of the fixed ring 61. On the other hand, the lock ring 23 is rotated in the reverse direction to release the threaded engagement of the female thread groove of the lock ring 23 and the male thread groove of the fixed ring 61, and the lens barrel 60 is rotated around its own axis. If the engagement between the portion 62 and the mount portion 22 is released, the lens barrel portion 60 can be separated from the extension tube 20.

As described above, the camera body 11 includes a control device, and the lens barrel unit 60 includes a motor, a power transmission mechanism, a circuit board 74, a flexible printed circuit board (wiring) 75, and a contact pin 76. Although the extension tube 20 does not include a communication means for electrically connecting the contact pin of the digital camera 10 and the contact pin 76 of the lens barrel 60, the extension tube 20 is connected to the camera body 11 and then the extension tube 20 is connected. When the lens barrel unit 60 is connected to the tube 20, the digital camera 10 can only perform shooting with manual focus (MF), and cannot perform shooting with autofocus (AF).
Since the diaphragm operating lever 81 is always urged to rotate clockwise in a front view by the urging force of the urging means that urges each diaphragm blade of the diaphragm mechanism 80 in the minimum diaphragm direction, the lens barrel 60 is extended. When separated from the tube 20, the throttle mechanism 80 is in the minimum throttle state. However, when the extension tube 20 is connected to the camera body 11, the power transmission lever 38 on the extension tube 20 side engages with the engagement / disengagement portion 82 of the aperture operation lever 81 on the lens barrel portion 60 side, and the power transmission lever 38 engages / disengages. The rotation of the portion 82 (aperture control lever 81) in the clockwise direction when viewed from the front is restricted. The rotational position of the power transmission lever 38 (around the optical axis A) at this time is a position corresponding to the rotational position (set aperture value) of the aperture adjustment knob 45, and is thus defined by the inner peripheral surface of each aperture blade of the aperture mechanism 80. The aperture diameter to be set is the set aperture value set by the aperture adjustment knob 45.
Further, when the photographer manually rotates the focus ring 70, the second lens unit L2 advances and retreats in the direction of the optical axis A, so that focusing by manual focus can be performed. Further, when the photographer manually rotates the slide adjustment ring 30, the movable cylinder portion 24 moves back and forth relative to the barrel-side cylinder portion 21, so that the focus position changes. Since the moving mechanism between the lens barrel side tube portion 21 and the moving tube portion 24 is constituted by a screw mechanism composed of the male screw groove 29 and the female screw groove 31, the moving operation of the moving tube portion 24 by the rotation of the slide adjusting ring 30 is performed. It is easier to carry out at a minute level than the moving operation of the second lens unit L2. Therefore, if the focus adjustment is performed at a minute level by the slide adjustment ring 30 after the focus adjustment is roughly performed by the focus ring 70, the photographer can perform the focus adjustment accurately and easily.
When the shutter button is fully pressed while the split lens barrel 15 is directed toward the subject, an observation image transmitted through the second lens group L2 and the third lens group L3 is captured by the imaging element of the camera body 11. Since the camera body 11 and the aperture mechanism 80 of the lens barrel portion 60 are not linked, the aperture diameter of the aperture mechanism 80 remains the set aperture value set by the aperture adjustment knob 45 even when the shutter button is fully pressed. Is unchanged. Therefore, when the shutter button is fully pressed, shooting is performed with an aperture value preset by the user.

An AF cylinder member having a communication means for electrically connecting the contact pin of the camera body 11 and the contact pin 76 of the lens barrel portion 60 and a linkage mechanism for linking the diaphragm mechanism 80 and the digital camera 10 is prepared. Instead of the extension tube 20, the digital camera 10 and the lens barrel 60 may be connected by the AF cylinder member. In this way, when the shutter button of the digital camera 10 is half-pressed, the motor of the lens barrel portion 60 operates, and the second lens group L2 moves forward and backward in the direction of the optical axis A by the power of the motor. Shooting by autofocus (AF) becomes possible. Further, in this case, the aperture mechanism 80 becomes an open aperture before the shutter button is pressed, and when the shutter button is fully pressed, the aperture mechanism 80 is electrically controlled to change the aperture diameter.
Further, the extension tube 20 may be provided with communication means for electrically connecting the contact pin of the camera body 11 and the contact pin 76 of the lens barrel portion 60. In the single AF mode, the second lens unit L2 is moved by an autofocus operation in response to a half-press operation of the shutter button of the camera body 11, and then the focus adjustment at a minute level is performed by the slide adjustment ring 30 of the extension tube 20. May be. On the other hand, in the case of continuous AF, after the second lens unit L2 is autofocused, the AF switch of the camera body 11 is turned off, and the focus adjustment at a minute level is performed by the slide adjustment ring 30 of the extension tube 20.

As described above, the extension tube 20 of the present embodiment includes the slide adjustment ring 30 that can adjust the focus at a finer level than the focus ring 70, so that the photographer adjusts the focus of the digital camera 10. It can be done easily and accurately.
Further, the configuration of the diaphragm adjustment mechanism provided in the extension tube 20 is simple, and the diaphragm adjustment mechanism can easily adjust the diaphragm value of the diaphragm mechanism 80 to an arbitrary (desired) value.

As mentioned above, although this invention was demonstrated based on the said embodiment, this invention can be implemented, giving various changes.
For example, the extension tube may be implemented as the extension tube 90 shown in FIG. An adjustment member for moving the movable tube portion 24 of the extension tube 90 with respect to the lens barrel side tube portion 21 is a slide adjustment knob (operation means) 91 that can rotate around a rotation axis extending in the radial direction of the extension tube 20. It is. A support member 93 having a through hole at the center is fixed to the upper surface of the lens barrel side tube portion 21, and a cylindrical rotation support member 94 is fixed to the through hole of the support member 93. A bearing 95 provided on the inner peripheral surface of the support member 94 rotatably supports the small-diameter shaft portion 92 constituting the lower portion of the slide adjustment knob 91. A first bevel gear 96 is fixed to the lower end portion of the small-diameter shaft portion 92. The first bevel gear 96 is a rotating body centered on the axis of the small-diameter shaft portion 92 and has a tooth portion on the peripheral surface thereof. On the other hand, the movable cylinder portion 24 is an annular body having a rotation center axis parallel to the optical axis A, and a second bevel gear (rotary member) 97 having a tooth portion meshing with the first bevel gear 96 on the outer peripheral surface thereof. Is supported. The entire inner peripheral surface of the second bevel gear 97 is formed with a female screw groove 98 that is a left-hand thread centered on the optical axis A, and a portion facing the female screw groove 98 on the outer peripheral surface of the movable cylinder portion 24 is A male screw groove 99 extending in the circumferential direction about the optical axis A and screwed with the female screw groove 98 (which is a left-hand screw) is formed. Further, a pressing member 100 is provided between the lower surface of the rear portion of the support member 93 and the movable cylinder portion 24 so as to be slidable in the direction of the optical axis A with respect to the rear portion of the support member 93 and not rotatable about the optical axis A. . Since the compression coil spring 101 that urges the moving cylinder portion 24 backward is contracted between the pressing member 100 and the moving cylinder portion 24, backlash between the male screw groove 99 and the female screw groove 98 is caused. The rear surface of the second bevel gear 97 and the front surface of the pressing member 100 are in contact with each other (the sliding position of the pressing member 100 is fixed). Further, on the inner peripheral side (optical axis side) of the bearing 95, an urging means for always maintaining the meshed state of the first bevel gear 96 and the second bevel gear 97 is provided.
Therefore, in the extension tube 90 of this modification, when the slide adjusting knob 91 is rotated in the clockwise direction in plan view, the second bevel gear 97 is viewed in the front view due to the meshing relationship between the first bevel gear 96 and the second bevel gear 97. And the movable cylinder portion 24 moves forward relative to the lens barrel side cylinder portion 21. On the other hand, when the slide adjustment knob 91 is rotated counterclockwise in plan view, the second bevel gear 97 rotates counterclockwise in front view due to the meshing relationship between the first bevel gear 96 and the second bevel gear 97 and moved. The cylinder part 24 moves rearward relative to the lens barrel side cylinder part 21.
Further, since the slide adjustment knob 91 is smaller (smaller diameter) than the slide adjustment ring 30, the moving operation of the movable cylinder portion 24 is simplified.
Although not shown in FIG. 9, the extension tube 90 is also similar to the extension tube 20, such as a power transmission lever 38, a rotation lever 40, a diaphragm adjustment knob 45, a cam mechanism that links the rotation lever 40 and the diaphragm adjustment knob 45, and the like. Therefore, if the aperture adjustment knob 45 is rotated, the set aperture value of the aperture mechanism 80 provided in the lens barrel portion 60 can be changed. Further, by adjusting the gear ratio between the first bevel gear 96 and the second bevel gear 97, the movement amount of the movable cylinder portion 24 may be finely adjusted.

Further, the slide adjustment ring 30 and the second bevel gear 97 are mounted on the movable cylinder portion 24 so as to be rotatable around the optical axis A and not slidable in the optical axis A direction. You may form the external thread groove which screws 30 internal thread groove 31 or the internal thread groove 98 of the 2nd bevel gearwheel 97. FIG.
Further, the aperture adjustment knob 45 of the extension tube 20 or the extension tube 90 is a ring member provided on the outer peripheral surface of the lens barrel side tube portion 21 so as to be rotatable around the optical axis A and not slidable in the optical axis A direction. You may connect a member and the rotation lever 40 by the connection member which penetrates the through-groove extended in the circumferential direction formed in the lens-barrel side cylinder part 21. With this configuration, the set aperture value of the aperture mechanism 80 can be adjusted by rotating the ring member around the optical axis A.
The extension tube 20 and the extension tube 90 may be configured by three or more cylindrical members, adjacent cylindrical members may be connected to each other so as to be relatively movable, and the lens barrel portion 60 is configured by a plurality of members that can be attached to and detached from each other. May be.
Further, if the rear end portions of the extension tubes 20 and 90 are connected to a lens barrel (eyepiece) with an eyepiece not shown instead of the camera body 11, the extension tube 20 (extension tube 90), the lens barrel portion 60, and the eyepiece concerned. A telescope can be constructed by a lens barrel.

DESCRIPTION OF SYMBOLS 10 Digital camera 11 Camera body 15 Division | segmentation type lens barrel 20 Extension tube 21 Lens barrel side cylinder part 22 Mount part 23 Lock ring 24 Moving cylinder part 25 Straight guide groove 26 Straight guide key 28 Male screw ring 29 Male screw groove 30 Slide adjustment ring ( Rotating member) (Operating means)
31 Female thread groove 32 Compression coil spring (biasing means)
33 Inner flange 34 Rotating ring 35 Long hole 36 Screw 37 Screw hole 38 Power transmission lever 39 Arc hole 40 Rotating lever 41 Fixed piece 43 Base 44 Ball support hole 45 Aperture adjustment knob (aperture adjustment member)
46 Rotating shaft 47 Compression coil spring 48 Click ball 49 Click groove 50 Detaching member 51 Large-diameter semicircular portion 52 Small-diameter semicircular portion 53 54 Stopper surface 55 Cam member 56 Cam surface 58 Stopper pin 60 Lens barrel portion 61 Fixed ring 62 Mount portion 63 Inner flange 64 3rd group support ring (lens support ring)
65 Straight guide ring 66 Straight guide groove 67 Second group support ring 68 Cam follower 70 Focus ring (adjustment ring)
71 Cam Ring 72 Cam Groove 74 Circuit Board 75 Flexible Printed Circuit Board (Wiring)
76 Contact pin 77 Front fixed ring 80 Aperture mechanism 81 Aperture operation lever 82 Engagement / disengagement part 90 Extension tube 91 Slide adjustment knob (operation means)
92 Small-diameter shaft portion 93 Support member 94 Rotation support member 95 Bearing 96 First bevel gear 97 Second bevel gear (rotary member)
98 Female thread groove 99 Male thread groove 100 Press member 101 Compression coil spring A Optical axis L2 Second lens group (moving lens group) (focus lens)
L3 Third lens group (photographing lens group)
S Tension spring

Claims (7)

A moving lens group, and a lens barrel portion having an adjustment ring for adjusting the position of the moving lens group in the optical axis direction;
An extension tube that is detachable from the lens barrel and does not incorporate a lens group;
A split lens barrel comprising:
The extension tube
A lens barrel side cylinder portion detachable from the lens barrel portion;
A moving cylinder part that is separate from the lens barrel side cylinder part and is movable relative to the lens barrel side cylinder part in the optical axis direction;
A rectilinear guide mechanism formed between the barrel side cylinder part and the movable cylinder part;
A male screw groove centered on the optical axis, formed on one outer peripheral surface of the lens barrel side tube portion and the movable tube portion,
A rotating member having an internal thread groove that is incapable of moving in the optical axis direction and rotatable about the optical axis with respect to the other of the barrel side cylinder section and the movable cylinder section, and has an internal thread groove that is screwed with the external thread groove;
Operating means for rotating the rotating member around the optical axis;
A split-type lens barrel comprising: The split lens barrel according to claim 1,
A split lens barrel in which the operating means also serves as the rotating member. The split lens barrel according to claim 1,
The operating means is a slide adjustment knob that is rotatable about a rotation axis extending in a radial direction of the extension tube and supports a first bevel gear centered on the rotation axis;
The split lens barrel, wherein the rotating member is a second bevel gear that meshes with the first bevel gear and whose rotation axis extends in a direction parallel to the optical axis. The split-type lens barrel according to any one of claims 1 to 3,
A split-type lens barrel provided with an urging means for urging both in a direction away from each other between the barrel side cylinder portion and the movable barrel portion. The split-type lens barrel according to any one of claims 1 to 4,
The lens barrel includes a diaphragm mechanism,
The extension tube
A power transmission lever that links with the aperture mechanism when connected to the lens barrel and opens and closes the aperture mechanism by rotating around the optical axis of the photographic lens group;
A diaphragm adjusting member provided rotatably on the outer peripheral surface;
An operating force transmission mechanism that transmits the rotational force of the diaphragm adjusting member to the power transmission lever and rotates the power transmission lever around the optical axis;
A split-type lens barrel. The split lens barrel according to claim 5,
The aperture adjustment member is an aperture adjustment knob that is rotatable about a rotation axis extending in a radial direction of the extension tube,
A split-type lens barrel in which the operating force transmission mechanism has a cam mechanism that converts a rotational force of the aperture adjustment knob into a rotational force about the optical axis. The split lens barrel according to claim 5,
The aperture adjustment member is a ring member rotatable around the optical axis;
The split lens barrel, wherein the operating force transmission mechanism is a connecting member that links the ring member and the power transmission lever so as to rotate together.

Images