A positionable mechanism includes a base unit, a frame unit, an optical image stabilizing (OIS) unit and a positioning unit. The frame unit and the OIS unit are mounted on the base unit. The frame unit is retractable with respect to the base unit between a storage position and a working position, and has a first surface. The OIS unit includes a movable carrier that has a second surface facing the first surface, an optical element that is mounted on the movable carrier, and a driving element that is operable to drive the movable carrier to move with respect to the base unit. The positioning unit is disposed between the first surface and the second surface, and is configured to position the movable carrier with respect to the frame unit when the frame unit is at the storage position.