[nigelblake]

I had some interesting little spots appear on a series of images, they seemed to get more obvious and numerous throughout the 90 frames taken. then the next series of pix taken a while later did not have them. On close examination they seem to me to be fine droplets of condesation that have formed during the period that my face was close to the camera, It was a cold day. So it would be advisable to keep you nose away from the back of a DSLR and avoid breathing on the camera body as much as is possible when shooting in cold conditions. this will help to keep the camera temperature stable, and therefore avoid such a problem.

[Peter Galbavy]

If it's a Canon, they will normally do you a wet clean FOC if you ask. Especially (and specifically) is you are a CPS member (http://cps.canon-europa.com/). I am lucky in that I live quick near their Elstree service centre.

[nigelblake]

Hi Peter
They are not permanent marks that have been left, but just temporary spots as a result of having my warm face against the cold camera.

[Peter Galbavy]

In that case you are lucky. I would have expected at least some residue... i guess warming at the right rate will just evaporate the water...