| 摘要 |
PURPOSE:To reduce driving noise, to improve efficiency and to reduce hunting and the difference of posture caused by the improvement of the efficiency. CONSTITUTION:This lens barrel is provided with an advance/retreat means to advance/retreat a focusing optical system in an optical axis direction, a pulley 3a to be driven which is turned centering around an optical axis so as to make the advance/retreat means act, a driving pulley 8 which is turned by obtaining driving force, an idler pulley 5 provided at a position symmetric with the pulley 8 by putting the pulley 3a between them with the optical axis as center, and a timing belt 6 to transmit the driving force of the driving pulley to the pulley to be driven. |
