A zoom lens includes a first lens unit, a second lens unit, a third lens unit and a fourth lens unit. The third lens unit includes a movable barrel, a first slidable member able to move in a first direction perpendicular to the optical axis, and a second slidable member able to move along a second direction perpendicular to the optical axis and also perpendicular to the first direction. The movable barrel includes a first Hall member and a first coil, the first slidable member comprises a second Hall member and a second coil. A first magnet is aligned with the first coil, and a second magnet is aligned with the second coil, both coils can be independently energized to compensate any shaking movements experienced by the Hall members.