I asked a friend, who is a great machinist, to make me a threaded 114 mm ring to screw in to my Red Lenses (18-50 and 50-150) The ring protrudes out 1/4" to allow the small, 2 stage Vocas DV Matte-box, to clamp on to. If you remove the outside 4x4 tray the 18-50 does not vignette. The 50-150 can use both trays. The Matte-box clamps on to the lip of the ring so as to not put undo pressure on the barrel of the lens (which could create a focus problem). The lens cap fits over it perfectly. Both rings were made in a couple of hours because I was leaving for a shoot in San Francisco and had no way use filters. I will get both rings anodized when I get the time. What's nice about this set up is that it is solid, will stay on the lens, takes 4x4 and 4x5.65 (vertical) filters. It does not require rods and all of the extra weight and paraphernalia. It works great and didn't cost me a small fortune to have a real matte-box with filtration.