I ma thinking of experimenting with Rollei IR 400 fil in my C330. Any one have any deas how to adjust the focussing as my understanding is with IR that the focus is different to the visual focus.
That depends very much on which filter you are using. The extreme cutoff filters will require a small adjustment out from the film but the red 29 and even the R72 most often can be shot without readjusting as the majority of the exposure is with red light which the lens is already focussed on. As stated above stopping down will guarantee a sharper focus.