Zoom lens assembly with switching mechanism from or to zooming photographing to or from macro photographing

In a zoom lens assembly having a zoom lens, a mount securing lens barrel which is to be secured to a camera body, an actuation ring capable of linearly moving in an optical direction for zooming and of rotating for focusing, with respect to the mount securing lens barrel, and a convert ring which linearly moves along the mount securing lens barrel without rotating at the zooming operation of the actuation ring to move the zoom lens in order to effect zooming photographing and which rotates together with the actuation ring with respect to the mount securing lens barrel to move the zoom lens in order to effect macro photographing when the actuation ring rotates past the shortest object distance position of the zoom lens at one zooming end postion, an apparatus for converting of zooming photographing to macro photographing and vice versa comprising an arrangement in which the convert ring is fitted on the periphery of the mount securing lens barrel and the actuation ring is closely fitted on the convert ring, and further comprising a ball retaining groove provided on the mount securing lens barrel, a radial through hole on the convert ring, a ball capable of omni-directional rotation is located in the radial hole so as to move therein, a ball receiving hole provided on the actuation ring, wherein said ball is located fbetween the ball retaining groove and the radial through hole during rotating of the actuation ring for focusing at one zooming end position thereof, to prevent the convert ring from rotating relative to the mount securing lens barrel, said ball comes out ot the ball retaining groove when the actuation ring rotates for macro photographing so that the ball comes between the radial through hole and the ball receiving hole to make the convert ring integral with the actuation ring in order to make a relative rotation of the convert ring to the mount securing lens barrel possible.