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: In order to reduce the noise of a lens barrel, the lens barrel includes a plurality of diaphragm blades, a driver driving the plurality of diaphragm blades, a first opening member that holds the driver, a second opening member including a plurality of facing portions opposed to the first opening member in an optical axis direction, and a plurality of buffer members disposed between the first opening member and the plurality of facing portions, respectively, wherein the plurality of buffer members position the first opening member with respect to the second opening member.

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 gear mechanism having a smaller diameter and achieving an accurate automatic drive includes a central gear supported on a rotational shaft, first and second side gears coaxially positioned on both sides of the central gear, planetary bevel gears supported within side surfaces of the central gear, and sun bevel gears respectively formed on the inner side surfaces of the first and second side gears which are engaged with the planetary bevel gears. At least one of the first and second side gears is provided with a torque adjuster for adjusting the torque of the side gear(s).

Abstract: A varifocal lens barrel includes a plurality of lens groups, each of which are linearly movable in the optical axis direction thereof without rotating about the optical axis during a zooming operation and during a focusing operation, including a base barrel which is linearly movable in the optical axis direction by rotation of a zoom operational ring, wherein lens frames of the respective lens groups are each supported by the base barrel.

Abstract: A gear mechanism having a smaller diameter and achieving an accurate automatic drive includes a central gear supported on a rotational shaft, first and second side gears coaxially positioned on both sides of the central gear, planetary bevel gears supported within side surfaces of the central gear, and sun bevel gears respectively formed on the inner side surfaces of the first and second side gears which are engaged with the planetary bevel gears. At least one of the first and second side gears is provided with a torque adjuster for adjusting the torque of the side gear(s).

Abstract: A varifocal lens barrel includes a plurality of lens groups, each of which are linearly movable in the optical axis direction thereof without rotating about the optical axis during a zooming operation and during a focusing operation, including a base barrel which is linearly movable in the optical axis direction by rotation of a zoom operational ring, wherein lens frames of the respective lens groups are each supported by the base barrel.