cheap and easy and great image quailty Cokin P series filter and a holder and set of adaptor rings so you can fit it on any lens you have and get Cokin P series ND4 and ND8 filters to go in it.
its works its reliable and cheap and easy to carry in your kit bag. Ive gone through Tiffen, Harrison, Schneider, Kodak Wratten ND Filters etc for my matte box and I always end up using the Cokins as I think they look better image wise. ND filters are disposable commodities , they will get scratched and dropped when on set or outside so scratching a $25 Cokin is OK , Scratching a $300 Tiffen is going to be painful!
