RED Mattebox...

[Jarred Land]

the outside diameter of the 18-85 is 142mm... the prototypes were a little smaller.

 

[Adrian T.]

the outside diameter of the 18-85 is 142mm... the prototypes were a little smaller.

Bummer! So this means it's not compatible to an MB20? :sad:

 

[Mitch Gross]

The Arri MB20 has a rear bellows assembly that can hold a 138mm filter. It therefore is physically larger than 138mm itself. I'll have to check the dimension of the opening, but 142mm is plausible. We'll have to see.

 

[Mitch Gross]

Arri just sent me dimensions on the rear rings of their matteboxes. They will work with the 18-85's 142mm diameter.

Rear ring diameters:

MB-18/19/20 - 143mm
MB-14 - 165mm

 

[Jarred Land]

Yes Mitch.. I think i confirmed that earlier, thanks for going through the extra steps though.

 

[Adrian T.]

But then we won't be able to use the bellows as a 138 mm pola filter holder.
Anyway, thanks for the clarification Mitch and Jarred.

 

[Mitch Gross]

You'll have to use 5.65 square filters for Polas on the MB-20. On the MB-14 you could use 5.5" round or 6x6 square. On either mattebox you can get square tray filter holders that house a large round filter with a little gear ring on the edge, so you turn the ring to rotate the filter instead of the tray itself.

 

[Mike Prevette]

I already tried begging for a 138mm retaining ring to be part of the front of the lens.

 

[Khan Bui]

Hopefully someone will come out with a lower cost 15mm (studio) swing-away system soon....

Try Redrockmicro Matte Box. They have both 19mm & 15mm.