Originally posted by Kitty I know pros would step up to 72mm or 77mm. I think this is because when they do wide angle lenses they need it this wide. What about for me? Right now I only own the 18-55mm kit lens. Someday I would like a telephoto zoom and some lens(es?) for macro. Wide angle, maybe that too.
The reason that "The Pros" buy 77mm filters is that the vast majority of constant "PRO" 2.8 zooms use 77mm filters, e.g. Nikon 24-70mm f2.8, Canon 24-70mm f2.8, Nikon 17-55mm f2.8, Pentax 16-50mm f2.8, Nikon 70-200mm f2.8, Canon 70-200mm f2.8, Sigma 70-200mm f2.8...I think I could go on for ages.
Now these lens are almost universally over $1000, and many are significantly more than that.
I think the cheapest lens that uses 77mm filters is the Sigma 10-20mm f4.5-5.6 and even then that is about $500-$600. As a beginner who has the kit lens and plans to get more lenses in the future I would say look seriously at the type of lenses you want.
A simple 77mm UV filter is $120, (if your going to buy one get a good one, look at my thread on the imact of low quality filters), and a CPL is up to $200 or more. This is more than the 35mm f2.5 lens.
I would say step up at most one or two sizes (i.e. get a 58mm filter), any more and you are simply wasting money.