I was wondering if I were going to purchase a ND Filer or 2 what brand and do I need a #2, #4 or both. I want to do some night shooting with the look of the tail lights of cars streaming by. Really dont kow what to get or how many. Do I need them for which lens the 18-55mm or the 70-200mm f/4 L. That is are will be the only lenses I own for a while cause my budget is gone for right now.

