Patent ID: 7679847

Claim:
A lens-barrel having an optical system, which is provided in a barrel, for directing an image of a subject to an image pickup device, said optical system including a first lens frame for holding a first lens and a second lens frame for holding a second lens, said first lens frame and said second lens frame being relatively movable with respect to each other along an optical axis, characterized in that: a flow path for generating air flow resistance when the air is released which is present between the first and second lens frames if these lens frames get close to each other is provided at a position where said first lens frame faces said second lens frame and a position where said second lens frame faces said first lens frame, wherein said flow path externally extends in a radial direction of any one of said first lens and said second lens from the outer peripheries of said first and second lenses at the position where said first lens frame faces said second lens frame and the position where said second lens frame faces said first lens frame; and a wall surface of said first lens frame and a wall surface of said second lens frame that constitute said flow path at a portion which is set at an outermost position in said radial direction in said flow path are formed as stopper surfaces that abut moderately against each other.