Gitzo Series 2 Off Centre Ball Head Macro The Circular PL filter removes The Circular PL filter removes reflection from water surfaces and glass windows while increasing contrast in landscape photography and darkening blue skies A stepping motor provides fast and accurate autofocus and is highly useful for video work This feature also helps to make using heavy equipment or long lenses safer Double quick release safety system: The system consists of two pins one fixed and one manually operated by means of a button that prevent camera equipment from suddenly dropping out of the head when the quick release locking knob is released