Inner focusing zoom lens and barrel thereof

Abstract

The present invention provides an inner focusing zoom lens and a barrel thereof. The inner focusing zoom lens and the barrel thereof implements a zoom ratio of as high as 15*+-[alpha], and ensures a well-balanced cam configuration for the smooth zooming and focusing. The invention is characterized in that the inner focusing zoom lens barrel that has a fixed barrel; a focusing cam barrel, a linearshuttle barrel, and a first cam barrel laid one over another in this order inside the fixed barrel; and a zoom linkage ring, a second cam barrel, and a 1st-lens-group sliding barrel laid one over another in this order outside the fixed barrel.

Description

technical field [0001] The present invention relates to an inner focus type continuous zoom lens and its lens barrel, more specifically to an inner focus type continuous zoom lens capable of achieving a zoom ratio of about 15 times and an inner focus type continuous zoom lens lens barrel. Background technique [0002] In the internal focus type high-magnification continuous zoom lens, the change rate of the focus lens with respect to the shortest distance side is large, and when trying to enlarge the shortest distance performance in one focus cam, the focal point in the other zoom area moves When it becomes larger, so-called zoom image shift (varifocal: when the focal length of the zoom lens is changed, the imaging position moves). In converting the zoom image movement into a focus cam curve of a zoom area, it is necessary to properly configure zoom parameters and focus parameters. However, in order to perform zooming and focusing operations smoothly, it is difficult to se...

AI Technical Summary

Problems solved by technology

[0008] However, since the overall length of the first cam barrel 16 in the optical axis direction is restricted, the layout of the first cam barrel guide cam, the third lens group guide cam, and the fourth lens group guide cam is limited by the length in the optical axis direction. constraints

In particular, in order to increase the magnification of the zoom ratio, it is necessary to increase the amount of movement of the third group lens and the fourth group lens along the optical axis direction, but it is difficult to achieve a good balance among the possible dimensions of the first cam barrel 16 in the optical axis direction. Configure the above guide cam

That is, if the above-mentioned guide cam is unreasonably arranged, there will be a problem that the shape and position of the above-mentioned guide cam will be restricted and the degree of freedom will be lost.

[0009] In addition, the amount of movement of the rectilinear barrel 18 increases with the amount of movement of the third lens group with respect to the full length of the possible structure of the fixed barrel 12. Therefore, there is a problem that when the fixed barrel 12 is extended on the long focal length side, the distance between the fixed barrel 12 and the rectilinear lens group increases. The fitting amount of the barrel 18, that is, the matching amount is small, and the required stability of the lens barrel cannot be guaranteed.

In addition, the anti-shake mechanism was not considered at all.

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