Lens barrel

A lens barrel comprising:

• a front sub-lens group provided on the object side and a rear sub-lens group provided on the image side, said front and rear sub-lens groups functioning optically when in a mutually close position and in a mutually distant position with respect to the optical axes of said front and rear sub-lens groups;
• a front sub-lens group frame for supporting said front sub-lens group and a rear sub-lens group frame for supporting said rear sub-lens group;
• a lens frame shift mechanism for causing said front sub-lens group frame and said rear sub-lens group frame to move relative to each other to obtain said mutually close position and said mutually distant position;
• a first lens group positioning surface, provided on said front sub-lens group frame, for positioning said front sub-lens group in the optical axis direction by contacting a portion of a rear surface of said front sub-lens group upon said front sub-lens group being inserted from the front side of said front sub-lens group frame;
• a front frame engaging portion provided on a rear side of said front sub-lens group frame,
• a second lens group positioning surface, provided on said rear sub-lens group frame, for positioning said rear sub-lens group in the optical axis direction by contacting a portion of a front surface of said rear sub-lens group upon said rear sub-lens group being inserted from the rear side of said rear sub-lens group frame;
• and
• a rear frame engaging portion provided on a front side of said rear sub-lens group frame,
• wherein said front frame engaging portion is held in engagement with said rear frame engaging portion in the direction of the optical axis while said front and rear sub-lens group frames are able to move in the optical axis direction relative to each other.