Im going to get a pol-filter for two if my lenses. The 70-200VR and Tokina 12-24mm. Both 77mm. But I want also the polfilter to fit my 18-70DX and it would be great to have it on 105VR Macro lens to. So, the questions are: - What Pol filter is the "best" - What kind of stepup/stepdown rings do I need to dit a 77mm on a 18-70 DX lens? - Will i get any vignetting with step up/down rings? That all.