I'm looking for a good filter and I found a couple, I was just wondering if there are any major differences between these two, besides the price tag. It will be going on my new Canon Eos XS. It seems one is a circular polarizing and one is just polarizing. What's the difference? [ame=http://www.amazon.com/HOYA-58CIR-Circular-Polarized-Filter/dp/B00006HOAQ/ref=sr_1_2?ie=UTF8&s=electronics&qid=1284398625&sr=8-2]Amazon.com: HOYA 58CIR 58mm Circular Polarized Filter: Electronics[/ame] [ame=http://www.amazon.com/Hoya-58POL-58mm-Polarized-Filter/dp/B000L9MGNE/ref=sr_1_8?ie=UTF8&s=electronics&qid=1284398625&sr=8-8]Amazon.com: Hoya 58POL 58mm Polarized Filter: Electronics[/ame] or could I just get this? [ame]http://www.amazon.com/Hoya-58mm-Introductory-Filter-Kit/dp/B000W3MPTO/ref=sr_1_4?ie=UTF8&s=electronics&qid=1284398625&sr=8-4[/ame] Thanks!