| 摘要 |
PROBLEM TO BE SOLVED: To improve the operability by driving a focus rotary cylinder by an MF ring through a differential mechanism at the time of manual focusing operation and directly driving the focus rotary cylinder by an AF power transmission member at the time of automatic focusing operation. SOLUTION: The differential mechanism consists of an MF power transmission member 3 which transmits the power from the MF ring 4, a power relay member 9 which receives the power from the MF power transmission member 3 and supplies the rotary driving force to the focus rotary cylinder 2 capable of rotating on the optical axis prescribing the optical-axial position of an optical system for focusing, and a free rotary cylinder 14 which is provided to the focus rotary cylinder 2 and freely rotatable on the optical axis. When the lens barrel is switched to the manual focusing(MF) operation, the focus rotary cylinder 2 is driven by the MF ring 4 through the differential mechanism. When the lens barrel is switched to the automatic(AF) operation, on the other hand, the focus rotary cylinder 2 is driven directly by the AF power transmission member 7 which transmits the power from a power source for automatic focusing directly to the focus rotary cylinder 2. |
