Abstract: A zoom optical system includes a plurality of lens groups, and upon zooming distances between adjacent lens groups change. The zoom optical system has a focusing lens group that moves upon focusing and an image-side lens group disposed adjacent to an image side of the focusing lens group. The zoom optical system satisfies the conditional expression 0.000<dL0t/dL1t<1.000, where dL0t denotes a distance on an optical axis between the focusing lens group and the image-side lens group upon focusing on an infinity object in a telephoto end state, and dL1t denotes a distance on the optical axis between the focusing lens group and the image-side lens group upon focusing on a short-distance object in the telephoto end state.

Abstract: A lens barrel includes: a first lens; a first tube that holds the first lens and moves along an optical axis; a focusing lens; an actuator that drives the focusing lens; and a second tube that holds the focusing lens and the actuator and moves along the optical axis.

Abstract: A lens barrel and an imaging device which can be miniaturized, the lens barrel with a movable cylinder that moves along the optical axis with a change in focal length; first and second drive units in the movable cylinder; and first and second lens driven by the first and second drive units respectively to move along the optical axis relative to the movable cylinder. The movement amount of the first lens relative to the cylinder when the focal length is changed to a second focal length from a first state where the first lens is at a position closest to a subject with a first focal length is less than the movement amount of the first lens relative to the cylinder when the focal length is changed to the second focal length from a second state where the first lens is closer to an image plane than the first state.

Abstract: A lens barrel includes: a first lens; a first tube that holds the first lens and moves along an optical axis; a focusing lens; an actuator that drives the focusing lens; and a second tube that holds the focusing lens and the actuator and moves along the optical axis.

Abstract: A zoom optical system (ZL) comprises a plurality of lens groups (G1-G7), and upon zooming distances between adjacent lens groups change. The zoom optical system comprises a focusing lens group (G5,G6) that moves upon focusing and an image-side lens group ((G7) disposed adjacent to an image side of the focusing lens group. The zoom optical system satisfies a following conditional expression. 0.000<dL0t/dL1t<1.000 where dL0t: a distance on an optical axis between the focusing lens group and the image-side lens group upon focusing on an infinity object in a telephoto end state, and dL1t: a distance on the optical axis between the focusing lens group and the image-side lens group upon focusing on a short-distance object in the telephoto end state.

Abstract: A lens barrel includes: a first lens; a first tube that holds the first lens and moves along an optical axis; a focusing lens; an actuator that drives the focusing lens; and a second tube that holds the focusing lens and the actuator and moves along the optical axis.

Abstract: A lens barrel is capable of changing the aperture diameter according to a zoom position while having a short length. A lens barrel includes: a aperture unit having a cam follower; and a moving tube having a cam groove for engaging the cam follower, the moving tube being provided at the outer circumference of the aperture unit and able to move along the optical axis direction.

Abstract: A lens barrel includes: a first lens; a first tube that holds the first lens and moves along an optical axis; a focusing lens; an actuator that drives the focusing lens; and a second tube that holds the focusing lens and the actuator and moves along the optical axis.