The standard adaptor ring is suitable for use with lenses up to a moderate wide-angle. It sits in front of the lens's front thread. The standard adaptor ring is compatible with lens focal lengths of approximately 24-28mm (35mm SLR equivalent) and upwards.
The adaptor ring screws onto the camera's lens and, in turn, the filter holder clips onto the adaptor ring. The adaptor ring screws onto the lens with a fluid action, thanks to the sturdy construction and aluminium screw thread.