Safeguard your lens and absorb UV light. Film and video are more sensitive to UV light than our eyes are. This often shows up as a bluish cast in images, especially shots from high altitudes and long distances, particularly over water. Ultra Violet filters are available in a variety of UV absorption levels.
Note! Tiffen wide-angle filters have low profile rings to prevent vignetting which can occur when using standard filters on ultra wide angle lenses. They do not have a front thread, and can not accept standard snap on lens caps