US 4,346,967 A · Zoom lens barrel for macrophotographing

Abstract

A two-lens group type zoom lens having a high magnification factor and simple structure yet having smooth transfer between normal zooming and macrophotographing positions. The positions of the first and second lens groups are defined by a respective zooming cam slot and lead slot formed in a cam sleeve. For focusing, a focusing operation sleeve is rotated to determine the position of the first lens group along the optical axis. A linear slot is provided extending from a telephoto end position of the zooming cam slot parallel to the optical axis direction of the lens. Additional circumferential slots may be provided extending from the zooming cam slot and lead slot and a click-stop mechanism utilized to stop the zooming operation sleeve at the telephoto end position and macrophotographing range position.

Claims10

Dependent claims

In a zoom lens barrel capable of performing macrophotographing operations including a zooming operation sleeve and a focus operation sleeve in which for zooming said zooming operation sleeve is rotated so that the positions of the first lens group and the second lens group are defined by a zooming cam slot and a lead slot formed in a cam sleeve and for focusing said focus operation sleeve is rotated to thereby determine the position of the first lens group in the direction of the optical axis, said zoom lens barrel being characterized in that a linear slot is provided extending from a telephoto end position of the zooming cam slot forwardly parallel to the optical axis direction of said lens groups.

A zoom lens comprising:

a fixed sleeve having a mount portion;
a support barrel disposed within said fixed sleeve and having a first guide pin rigidly coupled thereto;
a cam sleeve disposed around portions of said fixed sleeve, said cam sleeve being provided with first and second slots therein, said first guide pin being slidably disposed in said first slot, said first slot having at least a first linear portion extending at an acute angle to the optical axis of said lens and said second slot having an arcuate first portion forming acute angles with respect to said optical axis of an opposite sign of the acute angle formed by said first portion of said first slot and said second slot having a linear second portion extending parallel to said optical axis;
a zooming operation sleeve coupled to rotate with said cam sleeve;
a slidable sleeve having a second guide pin rigidly coupled thereto, said second guide pin being slidably disposed in said second slot and said slidable sleeve having a threaded inner portion;
and a focusing operation sleeve having a portion thereof in threaded engagement with said threaded inner portion.

3 more elements

Dependencies are inferred from the claim text.

Zoom lens barrel for macrophotographing

Life of this patent

Zoom lens barrel for macrophotographing

Life of this patent

Abstract

Claims10