Unless the dust is very close to the lens....
Just a quick note, a freind of mine and myself are going to be doing some experiments with IR cameras over the next few weeks.
What we plan on doing is makig a rig for two camera's so they will be mounted at 90 degrees to one another.
Hopefully we should be able to map an orbs movenent in 3D space,we should also be able work out speed and luminosity.
That is just one of our ideas and i will keep you all posted...........If you are interested.