Heliopan’s world-renowned 30.5mm IR RG 850 Filter is used for infrared photography with digital cameras and specialized infrared film. All surfaces emit infrared, invisible light waves as long as it is exposed to a light source. This nearly opaque IR RG filter blocks all visible light up to 850nm, allowing you to capture your subject radiating light waves imperceptible to the human eye. Filter Factor: (approximately 200x = 7.6 stops) | Constructed from the highest German Schott Optics, which guarantees incredible optical resolution. Our glass is specially ground and polished to minimize internal reflections, while ensuring that the quality of your images are not degraded by using our optics in front of your lens. It is also specially hardened to resist most impacts | Our standard 8-Layer Multi-Coating minimizes reflections and does not interfere with the resolution of your camera optics | Our precision cut brass ring ensures a secure and sturdy fit, are more resistant to side impacts, and less likely to bind or cross-thread after extended use | We do not source any materials outside of Germany in the assembly and construction of our products. All raw materials are prepared and hand-assembled in our factory and do not leave our facility until they are completely inspected by our quality technicians