IR-Cut filters are frequently used as heat-absorbing filters since they let the visible spectral range pass while the infrared rays from 780nm on are strongly blocked. These infrared filters are often used to protect IR-sensitive sensors or used in illumination systems. Note that for intense radiation from UV sources with wavelengths below 320nm (i.e., Xenon lamps), the transmission characteristics can be permanently changed. UV/IR-Cut is a multi-coated interference filter that completely blocks unwanted UV and IR radiation. It is especially recommended for applications where digital image sensors have not been fitted with an IR protection filter (or it was removed). There is little effect on off-axis angles; it is not recommended, however, for extreme angles of incidence. UV/VIS-Cut filters, also known as Infrared (IR) Pass Filters, absorb most of the ultraviolet and visible region and transmit the infrared region. For infrared images that consist of a combination of visible and infrared light, we recommend the R-72 Infrared (IR) Pass Filter (which passes 720nm and above). Note that lenses are typically designed for the visible spectrum, so focusing adjustment is required to obtain clear images in the infrared.