Dramatically reduces reflections from water and glass as well as rendering blue skies darker. Designed for use with telephoto lenses that provide a slip-in filter holder these filters reduce glare from non-metallic surfaces such as glass and water. Simply turn the rotating ring on the holder to find the most effective position. These filters do not affect autofocus or auto exposure operation. Both the C-PL1L and C-PL3L feature a diameter of 52 mm.