Ultraviolet filters or UV filters are optical filters that transmit UV light
. If they block the UV light, then they are UV cut filters or UV cut filters. UV filters are used in optical net components, in which they filter out the desired wavelength range of less than 400 nm, in photography and in digital cameras
.As far as UV cut filters are concerned, they used to be built into the optics of digital cameras to protect the images against blue cast, color distortion and to protect the image sensor
against damage from the UV light. Since modern digital cameras are equipped with UV protection, an additional UV cut filter can be omitted. A daylight filter can be built up by combining a UV cut filter with an IR cut filter.