I have a Canon HV20 (43mm thread), wide angle lens (72mm) and I will shortly be buying a DSLR with varied size threads dependent on the lenses used. I intend to buy a few ND filters and CC polariser. This is probably a basic question but is there any problem with buying at least a 72mm (maybe larger) in each of the filters I need and then use a combination of step up rings to match the lens filter size. Glass is expensive whereas the step up rings are relatively cheap.