JPS5926707A - Zoom lens barrel which permits macrophotography - Google Patents

Abstract

PURPOSE:To enable the continuous macrophotography with simple constitution by extending a straight part in a cam groove for zooming. CONSTITUTION:When a zooming operation part 15 is positioned on a long focus side L, a straight part 11c is extended from said position in a cam groove 11a for zooming, and the groove 8 in the straight chamber engaged with a guide pin 13 and the part 11c are parallel; therefore, if the part 3 is moved in the optical axis direction, the part 3, a sliding cylinder 5 and the pin 13 move integrally in the optical axis direction, thereby setting a macrophotographing state. The pin 13 is held engaged with the parallel groove 8 and the part 11c of the cam groove; therefore, the turning of the cam 10 is prohibited and the focusing in the macro region is accomplished satisifactorily. The macrophotography by which the photographing magifications are continuously increased is thus accomplished with the simple constitution.

Description

Detailed Description of the Invention The present invention consists of a first lens group and a second lens group, and focuses by moving the second lens group back and forth along the optical axis, and by moving both groups along the optical axis. In an 8172 group type zoom lens configured to perform zooming, the present invention particularly relates to a macro photographing mechanism of a zoom lens barrel having a focusing operation section and a zooming operation section.

In recent years, so-called macro zoom lenses or close-focusing zoom lenses have been introduced that go beyond the normal focusing range of zoom lenses and make it possible to take pictures at even closer distances, and there are various mechanisms available. has been devised and put into practical use.

Such a photographing mechanism is the same in a two-group type zoom lens. For example, there is a mechanism for performing macro photography by moving the second lens group further forward from the short focus side state. However, when macro photography is generally desired, the photographic magnification is low even on the long focus side of the zooming range, and the photographic magnification is desired to be further increased. In such a case, with the above mechanism, it is necessary to return the lens to the short focal length side and then switch to macro photography. Since it is shown in close-up, it becomes discontinuous and inconvenient.

There is also a mechanism for extending the entire lens system, but this requires a mechanism for extending it or a locking mechanism to prevent the entire lens system from being inadvertently extended during normal photographing, resulting in a complicated structure.

The present invention eliminates the above-mentioned drawbacks and provides a macro mechanism that can continuously increase the photographing magnification with a simple structure. Only when this happens, the lens group can be freely extended in a straight line, in addition to being extended by rotating the focusing operation unit, and it is possible to continuously enter macro photography mode from the long focus side and increase the photography magnification. It is something.

To explain an embodiment of the present invention, FIG. 1 is a side sectional view of a zoom lens barrel consisting of a two-group lens system showing an embodiment of the present invention.

3 is a diverging lens group, which is held in the focusing operation section 3. Reference numeral 2 denotes a second lens group of a convergent system, which is held by a holding frame 6. Reference numeral 5 denotes a sliding tube, which is screwed into the focusing operation section 3 with a helicoid screw 4. Reference numeral 7 denotes a fixed barrel having a mount portion for attachment and detachment to a camera (not shown), which fits into the sliding barrel 5 and the holding frame 6, and also fits into the cam barrel 1°. Reference numerals 13 and 14 denote guide pins protruding from the sliding tube 5 and the holding frame 6, which are connected to linear guide grooves 8 and 9 parallel to the optical axis formed in the fixed tube 7 and cam grooves formed in the cam tube 10. 11a and the lead groove 12a, and the rotation of the cam cylinder 1o causes the sliding cylinder 5. Zooming is performed by moving the holding frame 6 in the optical axis direction. 15
1 is a zooming operation section, which is fitted into the fixed tube 7. 16
is a transmission pin that transmits the rotation of the zooming operation section 15 to the cam cylinder 1o. 17 is an outer cylinder fixed to the fixed cylinder 7,
This defines the positions of the cam barrel 10 and the zooming operation section 15 in the optical axis direction.

FIG. 2 is an explanatory diagram showing the movement of the groove of the cam cylinder IO and the guide pin. The cam cylinder 10 has a cam groove 11a at the end of the long focal point side of the groove lla with which the guide pin 13 engages.
Subsequently, a straight groove Lie parallel to the optical axis is formed,
Further, a lead groove 12a with which the guide pin 14 engages is formed. 13a and 14a indicate the positions of the guide pins 13.degree.14 on the short focus side S, and 13b and 14b indicate the positions of the guide pins 1.3.14 on the long focus side.

13c indicates the position of the guide pin 13 during macro photography;
At that time, the guide pin 14 is located at the long focal point side
- Same position as the pin 14b.

FIG. 3 is an explanatory diagram showing the movement of the groove of the cam cylinder 10 and the guide pin in another embodiment of the present invention. On the long focal point side I-, a straight groove 11b is formed in the circumferential direction from the end where the guide pin 3b is located, and then a straight groove 11c is formed parallel to the optical axis from the macro photography section M. Correspondingly, a straight groove 12b is formed in the circumferential direction from the position of the lead groove] and 2a to the position of M.

13a and 14a indicate the positions of the guide pins 13 and 1.4 when the lens is on the short focal length side, 13b, ], 4b when the lens is on the long focal length side, and 13c and 14c when the lens is on the macro photography section M, respectively.

FIG. 4 shows a click stop mechanism added to the embodiment shown in FIG. 3 to distinguish between the normal zooming range and the macro photography section. 18 is a click ball, and 19 is a spring that biases the click ball 18. , 20 are set screws for fixing the spring 19.

21 is a zooming operation unit 15 using a click ball 18;
22a is a click groove corresponding to the macro photographing range.

FIG. 5 shows another embodiment of the click stop mechanism, in which the spring 19 fixed to the fixed cylinder 7 with a set screw 20 has a bent tip, and when the zooming operation section 15 is rotated, the spring 19
The tip of the button is in the range of the relief part 21 in the normal zooming range, and the click groove 22b is in the range of the spring 19 during macro photography.
By being located at the tip of the macro operation section 15, the macro operation section 15 can be click-stopped.

To switch from normal zooming to macro photography with a zoom lens barrel configured as described above,
The zooming operation unit 15 is located on the long focal point side. At this time, the linear guide groove 8 and the linear groove 11c, which are engaged with the guide pin 13, are both linear grooves parallel to the optical axis. Therefore, by moving the focusing operation section 3 back and forth in the optical axis direction, the focusing operation section 3. Sliding tube5. The guide pins 13 can be moved together in the optical axis direction, and a focusing operation in the macro area is performed. Furthermore, by stopping the forward and backward movement of the focusing operation section 3 in the optical axis direction at an arbitrary position and rotating the focusing operation section 3, the focusing operation section 3 is extended by the helicoid screw 4, and focusing operation in the macro area can be performed. will be held.

At this time, the guide pin 13 of the cam cylinder 10 is inserted into the linear guide groove 8.
．． By engaging with the straight groove 11c, rotation is impossible.

In the embodiment shown in FIGS. 4 and 5, when the zooming operation section 15 is rotated toward the long focal point side during a normal zooming operation, the zooming operation section 15 attaches the click ball 18 or spring 19 to the end of the relief section 21 on the long focal point side. The lens will stop once when it hits the button, but when taking a macro photo, if the lens is rotated further until it reaches the position of the macro photo section M, it will click and stop. At that time, since the grooves 11b and 12b are circumferential grooves, the focal length is the same as on the long focus side.

From then on, macro photography can be performed in exactly the same manner as in the previous embodiment.

In the embodiments shown in FIGS. 2 and 3, the lead grooves 12a are straight grooves, but both lla and 12a may be a combination of curved grooves. Further, in FIG. 4, the square groove 22a may be a square groove, and in FIG. 5, the V groove 22b may be a square groove.

According to the present invention as described above, a straight groove (or a partially inner circumferential groove) parallel to the optical axis continues from the end of the cam groove on the long focal point side of the second lens group of the conventional two-group type zoom lens barrel.
By simply providing this, it is possible to increase the amount of extension of the lens group, and it is possible to continuously move from the long focus side with high imaging magnification to the macro photography area, and at that time, it is possible to inadvertently move the zoom operation ring. doesn't move. In terms of focusing operability, both linear movement of the lens group and rotational movement using the helicoid screw can be used together, allowing for coarse focusing adjustment.

Fine adjustments can be made and focusing operations can be performed quickly. Furthermore, by providing a click stop mechanism to distinguish between the normal zooming range and the macro shooting range, erroneous operations can be avoided.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of an embodiment of the present invention, Fig. 2 is an explanatory view showing the movement of the groove of the cam cylinder and the guide pin in Fig. 1, and Fig. 3 is a cam cylinder of another embodiment of the invention. Fig. 4 is a partial front view showing the third rRI embodiment with a click stop mechanism, and Fig. 5 is a partial front view showing another click stop mechanism. . 4... Helicoid screw 5 ・Sliding tube 8.9...
・Linear guide groove 10...Cam tube Ija...Cam groove 12a...Lead groove 13.1.4...Guide pin 16...Transmission pin 18...Click ball patent applicant Asahi Optical Industry Co., Ltd. ,,1 Representative Toru Matsumoto --- Figure 1

Claims (1)

[Claims] 1. It has a zooming operation part (15) and a focusing operation part (3), and when zooming, the rotation of the zooming operation part (15) causes the zooming cam groove ( The position of the first lens group (1) and the second lens group (2) in the 111 direction in the light is defined by the lead groove (12a) and the position of -4 during focusing.
By rotating the focusing operation section (3) mentioned above, the
In the zoom lens barrel that defines the position of the non-lens group (1) in the optical axis direction,
1. A zoom lens barrel capable of macro photography, characterized by having a linear groove (llc) extending forward in the optical axis direction from 1.). 2 It has a zooming operation part (15) and a focusing operation part (3), and when zooming, the rotation of the zooming operation part (15) causes the zooming cam groove (lla) and lead groove ( 12a) respectively define the positions of the second lens group (1) and the second lens group (2) in the optical axis direction, and during focusing, the rotation of the focusing operation section (3) in 1.
1) In the zoom lens barrel that defines the position in the optical axis direction, there is a linear groove (Ilb) in the circumferential direction at the zooming cam groove (1,], the long focal point side end (7) of a). After extending the straight groove (llc) in the optical axis direction extending forward, a straight groove (llc) in the circumferential direction is further extended at the end of the long focal point side of the Li-1 groove (12a). ] A zoom lens barrel capable of macro photography, characterized in that a linear groove (12b) extending in the same circumferential direction as Ilb is provided. 3. It has a zooming operation section (15) and a focusing operation section (3), During zooming, the zooming cam groove (Ila) and lead groove (12a) provided in the cam barrel (10) rotate the second lens group (]) and the second lens group, respectively, by rotating the zooming operation unit (15). (2) in the optical axis direction, and during focusing, the rotation of the focusing operation section (3) allows the position of the lens group (1
) in the optical axis direction of the zooming cam groove (lla).
After extending a straight groove (llb) in the circumferential direction to L), further extending a straight groove (] lc) in the optical axis direction extending forward,
A straight groove (121)) in the circumferential direction, which is the same as the straight line iff (] 11) ) in the circumferential direction, is also provided at the end of the long focal point side of the lead groove (12a), and the zooming operation section (15) At the end (1,) on the long focal point side of the zooming operation section if & (llb), the zoom operation section if & (llb) is once switched to the macro photography section (M
) A zoom lens barrel capable of macro photography, characterized in that it is equipped with a Clicks 1 to knob mechanism that rotates again at the point of 1.