Lens barrel, lens driving apparatus, camera, and mobile information terminal

A method of controlling a lens mechanism including

• a plurality of lens groups each having at least one lens, the plurality of lens groups being located on a photographing optical axis in a photographable state;
• a telescopic cylinder containing therein the plurality of lens groups in the photographable state;
• a lens group driving device configured to drive at least one of the plurality of lens groups, at least one of the plurality of lens groups being collapsed to store the plurality of lens groups in a collapsed state and the at least one of the plurality of lens groups being expanded in the photographable state, the plurality of lens groups including at least one retractable lens group configured to be retracted from the photographing optical axis to a retracted position out of the photographing optical axis after being moved toward an image plane side on the photographing optical axis in the collapsed state and configured to be moved from the retracted position to a position on the photographing optical axis in the photographable state;
• a moving member which moves in a direction along the photographing optical axis, the at least one retractable lens group being moved between the retracted position and a position on the photographing optical axis according to the movement of the moving member in the direction along the photographing optical axis;
• a position detector configured to detect a change in a position of the moving member;
• and
• a retractable lens retaining frame configured to retain the at least one retractable lens group,
• wherein:
• the retractable lens retaining frame includes a cam portion,
• the moving member includes a contact portion configured to have contact with the cam portion, and
• the cam portion is configured to change a position of the at least one retractable lens group between the retracted position and a position on the photographing optical axis, the method comprising:
• driving the moving member in the direction along the photographing optical axis so that the contact portion moves the cam portion which changes the position of the at least one retractable lens group;
• and
• housing the at least one retractable lens group by retracting the at least one retractable lens group out of the telescopic cylinder according to the output of the position detector.