http://youtu.be/bR6A8xXm3HMWas at work today and needed to measure temperature of a heater plate. IR thermometer gives a different reading when aimed at the bare aluminium top of the heater than when aimed to the side, where the plate has a non stick PTFE coating bonded to the plate. Around 15C difference between the top and the side, within a 2cm range of movement.
