JPH02148025A - Zoom lens camera - Google Patents

Abstract

PURPOSE:To obtain a zoom camera which can execute a focal adjustment simple and at a low cost by executing a focal position adjustment of a zoom lens and a reference focal position adjustment by moving other lens group than a first group. CONSTITUTION:A rear lens group 12 is supported by a lens frame 18, and a screw part of the outside peripheral surface of the lens frame 18 and a screw part of the inside peripheral surface of a rear group sliding frame 19 are screwed to each other. By rotating the lens frame 18, the rear group lens group 12 can be moved in the optical axis direction. At the time of focusing, a projection 40a of a tool 40 is fitted into a groove provided on the lens frame 18, and the tool 40 is rotated, by which a focal position adjustment is executed. Therefore, since a front lens group 11 is not moved, the adjustment can be executed simply. In this regard, an interval between the front lens group 11 and the rear lens group 12 is varied by a regular operation in accordance with a shape of cam grooves 23, 24 of a cam cylinder 22.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to zoom lens cameras.

(Prior Art) A compact camera with a zoom lens generally employs a suppressed aperture shutter type aperture arrangement. In this method, when only the lens is moved in the optical axis direction during focusing, the distance between the lens and the aperture diaphragm changes, cutting oblique light rays, which may deteriorate lens performance.

Therefore, the applicant previously proposed a zoom lens in which a between-aperture shutter is installed in the front group of the zoom lens (Japanese Patent Application No. 1983-91831). As a result, since the aperture shutter is moved together with the lens, oblique light rays are not cut off, and deterioration of lens performance is prevented.

By the way, in a zoom lens, the focal position is adjusted by inputting parallel light created by a collimator to align the focal positions on the wide side and telephoto side. This adjustment is usually performed by adjusting the position of the front lens group and changing the lens spacing. However, in cameras that use the above-mentioned between-shutters, electrical components such as the shutter actuator are mounted in the front group of the zoom lens, so the focus position adjustment of the zoom lens cannot be adjusted as in conventional zoom lens cameras. If this is done using the front lens group, it will be difficult to secure enough space for adjustment.

There are also restrictions on the location of the cable that connects the electrical components and the camera body. Furthermore, the front lens group is exposed to the outside of the camera during zooming, so the adjustment section is susceptible to external pressure. Is that why it costs money to strengthen the front group members to protect it?
Two.

The second problem is that when setting the reference focus position of a zoom lens to have a depth of field from a predetermined close distance to a predetermined far distance, the reference focus position must be adjusted by moving the front lens group. It also occurs when doing.

(Object and Structure of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to make it possible to easily and inexpensively adjust the focus position of a zoom lens camera, and to achieve this L1 objective. Therefore, the rear lens group of the zoom lens is moved to adjust the focal position of the zoom lens and the reference focal position of the zoom lens.

(Example) The invention will be explained based on the drawings.

The first is a perspective view of a zoom lens camera according to the present invention, in which 1 is a camera body, 2 is a release button, 3 is a finder, 4 is a strobe, and 5 is a lens barrel. Further, numeral 6 is a strobe switch that is turned on when using a strobe, and 7 is a macro switch that is turned on when taking close-up shots.

FIG. 2 is a sectional view of the lens barrel of the camera shown in FIG. 1. In the figure, 10 is a film surface, 11 is a front lens group of a zoom lens, and 12 is a rear lens group of the zoom lens. Here, the front lens group is the lens group located closest to the subject, that is, the first lens group.

A cam bin 20 is fixed to the front group sliding frame 17, and a cam bin 21 is also fixed to the rear group sliding frame 19. A cam cylinder 22 is provided on the outside of the front group sliding frame 17 and the rear group sliding frame 19, and the guide bins 20.21 pass through cam grooves 23.24 of a predetermined shape formed in the cam cylinder 22, respectively. There is. On the outside of the cam tube 22 is the fixed 1→25 or the camera body 1.
It is fixedly provided. Straight guide grooves 26.27 extending in the optical axis direction are formed on the inner surface of the fixed barrel 25, and the cam bins 20.2 are formed in these straight guide grooves 26.27.
1 head is inserted in each.

A gear 28 is formed on the outer peripheral surface of the cam cylinder 22, and a drive gear 29 meshes with the gear 28. When the drive gear 29 is rotated by a manual lever (not shown) or a drive motor (not shown), the cam cylinder 22 also rotates. Kambin 20.2
1 moves linearly in the optical axis direction with its path regulated by the linear guide grooves 26 and 27, and the front lens group 11 and the rear lens group 12 move in the optical axis direction. The distance between the front lens group 11 and the rear lens BY l 2 changes in a predetermined manner depending on the shape of the cam grooves 23, 24, and the focal length of the entire optical system changes.

In this camera, the reference focus position of the zoom lens is set so as to have a depth of field from a predetermined short distance to a predetermined long distance (for example, 1.5 m to 0.000 m). In other words, it is possible to photograph a subject within the normal photographing range without performing a focusing operation.

An adjustment link 30 for adjusting the flange focus is provided on the outer periphery of the tip of the fixed cylinder 25. A threaded portion is formed in the adjustment ring 30 and the fixed barrel 25, and the two are screwed together through the threaded portion. The adjustment ring 30 has a flange 30a.
is formed, and this flange 30a is rotatably fitted into a groove formed in the cam cylinder 22. By operating an adjustment pin fixed to the adjustment ring 30 and rotating the adjustment flange 30, the cam cylinder 22 can be moved in the optical axis direction.

FIG. 3 is a diagram illustrating a focal position adjustment mechanism using the rear lens group. As shown in the figure, threaded portions are formed on the outer circumferential surface of the lens frame 1B and the inner circumferential surface of the rear group sliding frame 19, and the two are screwed together through the threaded portions. When the lens frame 1B is rotated, the rear group lens 12 can be moved in the optical axis direction, and thereby the focal position of the zoom lens can be adjusted.

For this adjustment, a tool 40 as shown in FIG. 4 is used, for example. The tool 40 is formed with three protrusions 40a, while a groove 18a is formed on the film surface side of the lens frame 18 to fit with the protrusions 40a, as shown in FIG. When adjusting, insert the protrusion 40a into the groove 18a and press T.
Turn tool 40. Then, the lens frame 18 rotates and the position of its front axis l- changes. Note that during adjustment, the tip of the protrusion 40g and the bottom of the groove 18a are separated by a slight gap d.

This eliminates the need for the second tool 40 during adjustment work, and prevents it from hitting the lens frame 18 and shifting the adjustment position of the rear lens group 12.Furthermore, if there is a rear lens group inside the lens barrel, Adjustment can be made smoothly by inserting the L-ring 40 into the lens barrel using the barrel as a guide. After adjustment, fix it with adhesive. Also, use the fixing pin 41 or cam pin 21 to attach the lens frame 18 to the rear group. It is also possible to fix it to the sliding frame 19.

FIG. 6 shows another embodiment of the adjustment mechanism for the rear lens group. In this example, instead of connecting the rear group sliding frame 19 and the lens frame 18 with screws, they are made into sliding surfaces, and an eccentric pin 42 as shown in FIG. 7 is rotated to the lens frame 18. The lens frame 18 can be freely attached and moved back and forth by rotating the eccentric bin 42. After adjustment, it can be fixed using a fixing pin or adhesive.

With the above method, the focal position of the zoom lens and the reference focal length of the zoom lens can be adjusted by moving the rear lens group. Adjustments can be made much more easily than by moving the front lens group.

In addition, parallel light is generally used when adjusting the focal position of a zoom lens, but according to the present invention, by irradiating a predetermined finite light from the reference focal position of the zoom lens, the focal position of the zoom lens can be adjusted. This provides the effect of being able to perform the adjustment and the reference focal point position at the same time.

As described above, the embodiments are as follows:
Although the present invention has been explained by taking a group zoom lens as an example, it goes without saying that the same effect can be obtained with a configuration having a behind-the-aperture shutter, and the present invention can also be applied to zoom lens cameras with other lens configurations. Of course it can be applied.

(Effects of the Invention) As described below, according to the present invention, the focal position of the zoom lens and the reference focal position of the zoom lens can be adjusted by moving the lens groups other than the first lens group of the zoom lens. This makes it easy to adjust the focus of a zoom lens camera.

[Brief Description of the Drawings] Fig. 1 is a perspective view of an embodiment of a zoom lens camera according to the present invention, Fig. 2 is a sectional view of the lens barrel portion of the camera shown in Fig. 1, and Figs. 3 to 5 1 is a diagram illustrating an adjustment mechanism for the rear lens group in the camera of FIG. 1, and FIGS. 6 and 7 are diagrams that do not show other examples of the adjustment mechanism for the rear lens group. 11...Front lens group, 12...Rear lens group, 22...
-・Cam kabura, 18...Lens frame, 40-・Tool, 42
・−・Eccentric bottle

Claims (1)

[Claims] A zoom lens includes a plurality of lens groups, and a reference focal point position of the zoom lens is set so as to have a depth of field from a predetermined short distance to a predetermined long distance;
In a zoom lens camera in which a driving member such as an aperture shutter is provided in the first lens group, lens groups other than the first lens group are moved in the optical axis direction relative to the first lens group to adjust the focus position of the zoom lens and zoom. A zoom lens camera characterized by being provided with an adjusting means for adjusting a reference focal point position of a lens.