Do you mean back then, now or both?
Or do you mean film vs digital resulting in comparitive image quality? I really don't know what I'm talking about and would like a bit more detail.
Because obviously there are a lot of lower budget films and indie films being shot digitally now and for the cheap with pretty good results (not film quality though)
An example: Was 300 filmed digitally and as of 2006 would it be cheaper to shoot it digitally or on film regarding everything you mentioned above?
Sorry that's a lot of questions and sorry for the derailment but you bought out some curiousity on my behalf.
In addition to your points further cost factors between Ep1 and Ep2/3 would be shooting locations. Ep1 was in the UK at Elstree while the 2 sequels were filmed at Fox Studios in Australia. Australia being considerably cheaper.