The Hoya 77mm R72 Infrared Filter is a specialized filter used for infrared photography with digital cameras and specialized infrared film. This nearly opaque filter blocks all visible light up to 720nm/ enabling recording of subject matter and scenes that are not visible under normal conditions. Due to the nature of infrared photography/ the filter factor for this filter is highly variable and depends largely on the ISO sensitivity in use and lighting conditions.This filter is constructed from high-quality optical glass and is set in an aluminum filter ring to provide increased rigidity and prevention from filter jamming.<br />