Thought I'd just share this tidbit I found out for others in my situation: So to minimize all of the camera stuff I carry- I decided to use only one size of filter, 52mm, and get step up rings in 37, and 46. The only lenses I have that have a filter larger than 52mm, was the 75mm @ 58mm (not counting zooms- which I really don't use filters on anyway). So I scrounged up an old 58mm to 52mm step down ring to see how much vignette I'd get on it... and it to my surprise produceded no vignette at all when I put a filter in. Yay! I don't have to carry around extra 58mm filters!