I'm new to slr cameras just picked up my first dslr camera a week ago "rebel Xsi". My question is this, I just picked up a Canon EF 75-300mm f/4-5.6 III USM Telephoto Zoom Lens and I currently don't have a filter for it. I want to buy a filter for it and just want to know what the differences between these filters are. Any suggestions would be greatly appreciated.

