Used for Infrared Photography Blocks Visible Light Up To 720nm 50% of IR 720nm Can Pass K9 High Quality Optical Glass Construction Multi-Coating Surfaces Anti-water and Anti-oil Coatings Overview: The Haida NanoPro Infrared 720 Filter is designed to help capture images of how a subject reflects or transmits infrared light. Infrared light waves occupy the space in the electromagnetic spectrum behind visible light due to their longer wavelengths. Many surfaces and materials react to or emit infrared light waves differently than visible light waves, which provides the potential for photographs of subjects or subject properties that are otherwise invisible to the human eye. Such images require an infrared-sensitive medium such as infrared film or a digital photographic sensor, which may be more effective when used without the infrared-blocking filters that are frequently built over them. Conventional light sources such as the sun, photographic strobes, or incandescent lighting may be used to provide infrared illumination. However, because infrared films or digital photographic sensors can be more sensitive to the relatively higher energy and shorter-wavelength visible light those sources also emit, the effects of infrared light can be otherwise obscured. This Haida NanoPro Infrared 720 Filter makes it possible to capture images of how subjects are illuminated by infrared light by blocking ultraviolet and visible light waves less than 670nm from entering the lens it is mounted onto. Instead, visible and infrared light at or above 670nm is progressively transmitted, with 50% of infrared light at 720nm and up to 98-99% of infrared light at 950nm. Haida NanoPro IR 720 filters are constructed from K9 High Quality Optical glass and feature anti-oil, anti-water coatings to help reduce surface reflections for increased contrast and clarity, while additional hydrophobic coatings result in an improved beading effect when in contact with water for easy cleaning