Normal digital cameras use filters to limit the color spectrum that reaches the sensor to the Spektrum visible to humans (~380-780nm). Through expansion or Replacing the filter turns it into a “full spectrum camera” that records the entire Spektrum that the sensor can capture (~350-1100nm). Cameras that have a filter thread in front of the lens can use an infrared filter to block Spektrum that is visible to people and then "see" it - depending on the filter selected, 680..720..800-1100nm, i.e. a range that is otherwise not visible to people. The "infrared camera" conversions in my shop already have a ~700nm cut-off filter installed. For full spectrum or There are various applications for infrared cameras. In addition to surreal recordings for artistic purposes, museums and auction houses.