The Heliopan 36mm IR RG 610 Filter is used for infrared photography with digital cameras and specialized infrared film. This nearly opaque filter blocks all visible light up to 610nm, 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. Additionally, it is recommended that auto-exposure and autofocus functions are disabled during use for greater control over the results.