The Heliopan Series 7 Infrared RG 665 Filter is used for infrared photography with digital cameras and specialized infrared film. This nearly opaque filter blocks all visible light up to 665nm, 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.
The front and rear surfaces of the filter both feature a single anti-reflection coating. Each coating helps to increase light transmission by reducing reflections, scattered light, and ghosting. Additionally, they offer protection to the filter substrate while helping to keep the glass clean for longer than uncoated glass.
This Heliopan filter is constructed from Schott glass for increased optical clarity and color fidelity. It features a brass filter ring for enhanced durability.