Attached Link: sensitivity comparison

Yes, a bit of a hotspot is created when using an IR filter. It is better on some cams and worse on others. Briefly, an IR filter filters out most of the visible light spectrum and forces the camera to shoot at a longer exposure, capturing data from the IR range fo the spectrum. Digicams have what is called a "hot mirror" that filters out much of the IR light, but some still gets through. Older cameras were much more sensitive to IR light while most of the newer ones have a harder time capturing it. And my cam is supposed to be one of the worst, but you see that it still manages it. ;] The attached link lists cameras and their sensitivity to IR light. The best out of the box are the old Oly C2000/2020, Nikon Coolpics 950, D50, Pentax *ist DS, and Minolta D7. Or you can do what others have done and take apart your camera and replace the hot mirror with a same size piece of optical quality glass or IR filter. You then have a VERY fast dedicated IR camera. There are also companies that will do this for you...for a price. My ultimate dream would be to own the Japanese imported Canon 20Da, but that just isn't doable right now. I hope more IR cameras come out in the not too distant future.

Kort Kramer - Kramer Kreations