The Sigma 46mm Rear Circular Polarizing Filter (A00530) is designed to be used individually with the Sigma Rear Filter Holder (A00090) . Light rays which are reflected become polarized. Polarizing filters are used to select which light rays enter your camera lens. They can remove unwanted reflections from non-metallic surfaces such as water or glass and also saturate colors providing better contrast.
The effect can be seen through the viewfinder and changed by rotating the filter. The filter factor varies according to how the filter is rotated and its orientation to the sun.This results in a noticeable reduction of glare and reflections from non-metallic surfaces and an increase in the saturation of skies and foliage.
This filter is multi-coated to prevent internal ghosting as well as reflections and features an aluminum-alloy filter ring for durability while remaining lightweight.