Infrared Training Center

Tuesday, July 20, 2010

Why does my Infrared Camera read higher than my Infrared Temperature Gun?

 ITC Logo TM 250 The answer is, in a word, resolution. Take a look at the image below.
7-20-2010 1-48-44 PM
The infrared camera is able to locate and measure much smaller objects than an IR temperature gun. Note the spot measurement on the infrared image; its reading is 250 F. Contrast that to the average area measurement typical of an infrared gun at a reading of 184 F. The gun is averaging all the hot areas along with the cold areas of the grating we see in the image.

Another common question is why the IR camera reads a higher temperature than a contact temperature probe? Contact temperature probes require an extremely good contact in order to read a decent temperature. In fact these probes measure their own temperature, so if the heat transfer is not good from the substrate, and the probe sensor is colder than the surface, the temperature will be lower. Also remember that contact thermometers act as heat sinks, sucking heat out of a surface.


  1. May I ask for help if any one knows what materials/glass/thin films/etc can be used for a window for IR cameras to look through to receive signals from a closed chamber?

    Many thanks in advance

  2. That partly depends on the characteristics of the camera you want to use.

    For MW cameras consider sapphire, Zinc selenide

    For LW cameras consider zinc selenide, germanium

    There are other materials as well. Contact for more information.