Different to Thermography, where pictures are taken with
an expensive Thermal imaging / Infrared Camera (ca. 20 000 - 40 000 USD)
which is able to make visible infrared radiation in the "far infrared" of about 5-15 µm, the "ordinary" infrared photography
is an inexpensive method which takes place in the infrared wavelenghth range very close to the visible light at
abt. 0,8-1 µm (800-1000 nm).
The same tree three times: infrared picture (left) und als "normal" photography (center).
On the right just for comparison: the negative image. It looks a bit alike the infrared one,
but actually it is a totally different kind of picture.
Austria: the Alps, on the left as infrared image, with far better contrast and more visible details. This is caused by the fact that infrared light beacuse of its larger wavelength it is less scattered / deflected by the various small particles in the atmosphere. By the way that´s the same reason why the sky is blue and sunset is red: blue light is diverted much more than red light, so the ray looses more and more blue light as longer it is passing the atmosphere.
Das Bild zeigt die Aussicht der Kitzbühler Webcam auf der Bichlalm:
links als Infrarotaufnahme, rechts das "Normalbild" (am 26. August 2005)
Landscape, Infrared + RGB