Ok so I went to a camera shop to buy a uv filter and a polarizer.. then they say "buy two get one free!" agh! That means I had to choose one of the special effect filters that I really didn't need. (my g3 already has an nd and a good macro trick) So I somehow picked a spot filter because I really didn't care. It's basically a closeup lens with a hole in the middle. So how do I use it? (what zoom, dof?) And how do I reduce the ring from the hole in the thick glass?