Lens barrel

摘要

A lens barrel is provided that includes a zoom optical system with an optical axis. The lens barrel also includes a first and a second lens group. The first lens group has a first curved part and a first straight part when viewed axially along the optical axis. The second lens group is axially and movably disposed relative to the first lens group and has a second curved part and a second straight part when viewed axially along the optical axis. The lens barrel is configured to change between an imaging state and a retracted state. In the imaging state, the first and second lens groups are aligned with one another along the optical axis. In the retracted state, the second lens group is disposed off center from the first lens group so that the first straight part is substantially parallel with the second straight part.