In the thermal imager article in PUG I mentioned that it is very important that you be careful and look at the sensor resolution of the unit that you want to buy. Ebay is littered with low resolution units from Wahl, Irisys, and Heetseeker. These units have a 16x16 array, in other words, 256 "pixels"

Bare minimum I recommend for paranormal work, is a 120x120 array. The B2 I have has a 120x160 array (19,200 "pixels"). Obviously if you can afford it, try to get one with 320x240 sensor resolution.

To graphically illustrate the difference, the first picture is from one of the cheap 16x16 units that has been repurposed as a fever detector and marketed to airports.

And the larger resolution of the FLIR unit:

regards

Andy