JPS58192004A - Inclination adjusting mechanism of front and rear groups of photographing optical system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention solves the problem of collapsing of the front group lens and rear group lens in a lens barrel using a method in which the photographic lens is extended linearly using a straight bar as a guide, and of the entire optical system. Regarding the adjustment mechanism.

Generally, a helicoid is used to extend the photographic lens barrel, but a method in which the photographic lens barrel is extended in a straight line using a straight bar as a guide has also been adopted.

First, let us explain the latter conventional example.
FIG. 1 is a front view of the front lens group, and FIG. 2 is a sectional view of the main part of the photographing lens barrel on the optical axis.

In the figure, the front lens group la, lb held in the lens barrel 2
The IC and the rear group lens 1d held on the rear base plate 6 constitute a photographing optical system, and the bar 3 fixed to the lens barrel 2 is inserted into the fitting holes 5a and 6a provided on the front base plate 5 and the rear base plate 6, respectively.
Guided by K. Further, the infinite adjustment screw 4 screwed into the lens barrel 2 is wound around the bar 3, and its tip is brought into contact with the feeding cam 8 by a compression coil spring 9 interposed between the lens barrel 2 and the front base plate 5. A U-shaped guide groove 2a is provided in the lens barrel 2 at a position substantially opposite the bar 3 to the optical axis center of the lens barrel 2, and a guide provided protruding from the rear base plate 6 is provided in the guide groove 2a. The pin 6b is fitted. In addition, 7 is nya, ri, 10
is the film surface.

In the conventional lens barrel extension mechanism configured as described above, the lens barrel 2 holding the front group lenses la, lb and IC is moved by the extension cam 8V to the bar 3 and the guide pin 6b.
It is controlled by the guide and 17 to feed it out in the front and rear direction. In the case where such a system is adopted, when the required accuracy of the optical performance of the photographic lens is strictly 1 to 1, for example, when the optical tilting accuracy of the front group lens and the rear group lens is required to be about 5', It is extremely difficult to meet this level of precision through normal assembly of single parts, and it is necessary to finish the parts with extremely high precision.

The present invention eliminates the drawbacks of the conventional example and adjusts the optical inclination of the photographic optical system so that the required precision in terms of optical performance can be satisfied even if the processing precision of the single component of the photographic lens barrel is relaxed. The purpose is to obtain a mechanism for

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a sectional view of the main part on the optical axis showing one embodiment.

In the figure, the same components as those in the conventional example shown in FIG.
It is supported by a spring 11 interposed between and a plurality of adjustment screws 13 screwed into a presser ring 12 fixed to another receiving portion 6d. Further, the rear base plate 6 is fixed to the camera body 14 by a plurality of screws 16 with adjustment spacers 15 interposed therebetween.

The front and rear group tilt adjustment operations of the photographing optical system of this embodiment configured as described above will be explained.

First, the front group lenses la, lb and IC and the rear group lens 1d
Suppose that optical collapse has occurred in the relationship with .

In order to adjust this tilting, adjust screw 13 of the rear group lens.
By adjusting the amount of screwing in, the inclination of the rear group lens 1d can be adjusted. In this way, it is possible to eliminate the tilting of the front group lens and the rear group lens, but as a result, the front group lenses la, 1b
, l, IC and the rear group lens 1d may be combined and the entire structure may be tilted.

Therefore, in order to correct the inclination of the entire lens system with respect to the film surface 10, when fixing the rear base plate 6 to the camera body 14, screws 16 are inserted through spacers 15 having different thicknesses.
Tighten the screws.

In this way, it is possible to satisfy the accuracy of tilting the entire lens system with respect to the film surface 10.

The present invention is based on the above description 1. If the photographic optical system is separated into a front group and a rear group, the optical tilt of the front and rear groups can be reduced by adjusting the tilt of either lens system to the tilt of the other lens system. At the same time, it is possible to adjust the accuracy of the tilting of the entire lens optical system with respect to the film surface caused by this operation, so it is possible to loosen the processing accuracy of each single component that holds the lens system. Moreover, it has the effect of satisfying the required accuracy in terms of optical performance.

[Brief explanation of the drawing]

Figure 1 shows a photograph taken using the conventional straight bar extension method.
Figure 2 is a sectional view of the main part of the lens barrel taken on the optical axis, and Figure 3 is a front and rear group tilt adjustment mechanism of the photographic optical system of the present invention. FIG. 2 is a sectional view of a main part on the optical axis showing an embodiment of the present invention. la, 1b, 1c...front group lens, 1d...rear group lens, 2...lens barrel of front group lens, 5...front base plate, 6...
... Rear base plate, 11 ... Spring, 12 ... Presser ring, 1
3... Rear group adjustment screw, 14... Camera body,
15...adjustment spacer, 16...screw.

Claims (1)

[Claims] 1. In a camera in which a photographing optical system consisting of a front group lens and a rear group lens is mounted on the camera body as a unit, at least one of the front group lens or the rear group lens is tilted about the photographing optical axis. and an adjusting member that can be attached to the camera body by tilting the optical system unit with respect to the photographing optical axis. Adjustment mechanism.