For softening skin tones, etc. to give the film look to HD digital footage, what are thoughts on using actual screw on lens filters (Tiffen, Hoya, etc) compared to doing the filtration in post? Are they the equivalent? For example I noticed that Tiffen came out with a software package for applying Tiffen filtration to digital footage; but I just can not believe that that would give the same effect as from shooting with the actual filter in place-- wouldn't the lens filter emphasize more what was in the focal plane, whereas the software filter (f/x) would act on everything in the frame?