PROBLEM TO BE SOLVED: To provide a zoom lens barrel never changing an im-focus state at the time of varying power. ;SOLUTION: In the zoom lens barrel which is provided with a lens supporting member 10 supporting a lens group for executing both of variable power and in-focus operations and being movable in the directions of an optical axis and a rotation on the optical axis, a cam ring 5 which is provided with one cam part 5c for prescribing the operations of varying the power and focusing of the lens supporting member 10 in common and rotatable on the optical axis and executes the focusing operation in such a manner that the lens supporting member 10 is rotated with respect to the cam ring 5 whose rotary motion is stopped and the operation of varying the power in such a manner that the cam ring 5 is rotated with respect to the lens supporting member 10 whose rotary motion is stopped, loading members 16 and 17 for applying load torque in the rotational direction to the lens supporting member 10, to prevent it from taking the rotary motion at time of variable power operation.;COPYRIGHT: (C)1997,JPO
展开▼
