I have a 49mm 3 stop ND filter and a 46mm Polarizer (from an old point and shoot), but both are too small for the 16-70 (55mm) that I purchased not long ago and the polarizer is too small for all of my lenses (most are 49mm) except the kit lens. Since I have to invest in new filters, what size should I get? Do I go for 55mm because that is the largest I have now, or do I go to something like a 77mm so I have my bases covered if I get something larger? Also any brand suggestions? I currently have Marumi filters and they seem pretty good.