I am aware that modern lenses are not necessarily suitable for infra-red photography as they often produce hotspots – I have read that this is due to the type of glass used in modern lenses. So, before I get my camera converted, I thought I would undertake some testing of my lenses.
First up is my 10-24mm wide-angle zoom. The presence and intensity of the hotspot varies with the wavelength passed by the filter:
Other tests of this lens with different apertures showed the same problem. A similar result is for the 18-55mm lens:
The best lens proved to be the 55-200 telephoto zoom:
At least I have some idea what to expect from my modern lenses…