An improved method and module for auto focusing utilizes a variable thickness focus element. A different thickness, and thus a different focus, is optically coupled to an image sensor by rotating the focus element. Movement along the optic axis is not required. This minimizes the amount of space required to provide the auto focusing function, allowing a mobile device utilizing the module to be smaller while still providing the auto focusing feature. In addition, the mechanism for rotating the focus element is smaller and/or less complex than a mechanism for moving a lens assembly along the optic axis, further allowing the device to be smaller. The focus element has less inertia than conventional lens assemblies and so required less power to move and allows for fast focusing.