Abstract: A drive apparatus for a zoom lens barrel having at least two movable lens groups, one of which is used also as a focusing lens group comprising: a pair of lens frames which respectively hold the two movable lens groups, a pair of driven pins which are integrally provided on the lens a drive cam plate which is provided with a pair of cam surfaces which engage with the corresponding driven pins and which is rotatable about an axis, a rack plate which is supported to move in the optical axis direction of the movable lens groups and which is provided with an engaging portion which engages with the driven pin of the movable lens group that is used also as a focusing lens group, a first drive mechanism which includes a first motor for swinging the drive cam plate in the forward and reverse directions, and a second drive mechanism which includes a second motor for moving the rack plate without having an influence on the angular position of the drive cam plate.

Abstract: A lens barrel which has a lens holding member for holding a lens unit, a movement cam mechanism for moving the lens holding member in an optical-axis direction, a biasing member for biasing the lens holding member to shift a slide allowance of the movement cam mechanism in one direction, a biasing force receiving member for receiving a biasing force of the biasing member and a biasing force adjustment cam mechanism for moving the biasing force receiving member in the optical-axis direction so that the biasing force of the biasing member remains the same.