Patent ID: 8625980
Filing Date: 2014-01-07
Classification: G02B,G03B

Abstract:
1. A lens barrel that changes a focal length by moving at least one of a first lens group and a second lens group in an optical axis direction, and that increases a barrel length under a shooting condition and decreases the barrel length under a retracted condition, comprising: a first holding frame adapted to hold the first lens group; a second holding frame adapted to hold the second lens group; a light-amount adjusting member adapted to adjust an amount of light that transmits an optical system by changing a diameter of an aperture, said light-amount adjusting member being located between said first lens group and said second lens group; a third holding frame adapted to hold said light-amount adjusting member; a cam mechanism adapted to move said first, second, and third holding frames in the optical axis direction so that a part of the second lens group is inserted into the aperture of said light-amount adjusting member and concave and convex surfaces, which are faced to each other, of the first and second lens groups are overlapped in the optical axis direction under the retracted condition; and a light-amount varying member adapted to be held by said second holding frame aside from said light-amount adjusting member, wherein the diameter of the aperture of said light-amount adjusting member is enlarged and said first, second, and third holding frames are moved in the optical axis direction, when shifting to the retracted condition from the shooting condition, and wherein a distance between said light-amount adjusting member and said light-amount varying member under the retracted condition is shorter than that under the shooting condition.