The Phase One TG1 Tungsten Filter is designed to be used with digital camera backs and tungsten lights.As the camera back is “daylight balanced,” the Hasselblad Camera Filters make the optical color correction before preparing the digital imageAs a result of using the filter and the camera back with tungsten lights, you can achieve bright pictures with great image clarity, and perfect color rendition Also, the Phase One TG1 Tungsten Filter has a very low attenuation of light in the visible range and is very efficient when reduced infrared lightTherefore, you don’t require a separate infrared filter while using the Hasselblad Camera Filters