Filter Control : What do you think?

[Petr Tomkevich]

I am not experienced with filter placement and am about to get my first matte box. Looking at the Oconnor O-Box or Arri MB20ii. O-Box takes 2 filters + 1 round filter, MB20ii will take 3 filters + 1 round filter. My first question is, is it necessary to have 4 filters? I am thinking UV in the front, followed by a Polarizer, ND and a round Hot Mirror in the back. Will this setup come in handy or is it completely unnecessary? Also, is there a better order to put the Hot Mirror compared to the ND or does it not matter?
-Petr

 

[Cail Young]

1) Hot mirror, when used, must always be the filter furthest from the lens, so using a round in the back tray is a bad idea.
2) A UV is probably un-necessary.
3) Generally round polariser filters are used so you can rotate with impunity.

3 stages incl round gives you a hot mirror, a single ND, and a pola. 4 stages incl round will let you stack two NDs. If you have really strong single ND filters (1.8, 2.1) then 3 with round should be fine.

 

[Steve Sherrick]

Petr, I'm really liking the O-Box. But you have to take it for what it is. Essentially, it is not an MB-20. No swing-away, less stages. What it is though is a very well built matte box for the money. I have a 138mm Pola which works well. I have a setup that works well with still lenses too. Make sure to get the side brackets, the side flags, and if you need 19mm get the bridge and 19mm adapter. That also sets you up for using the O-grips if you want to.

The only complaint I have is the filter knobs are a bit small if you have large fingers. But workable, especially if you mod those. For about $1700 you get a really good matte box with just a few compromises. MB-20 is far more expensive and doesn't compromise very much.

 

[Petr Tomkevich]

Thanks guys. Exactly what I needed to know.

 

[brian leisring]

+1 on the obox filter knob issue, I just lost a ND .6 to that little flaw. Overall the Obox is a really nice matte box, I dropped the 15mm attachment and use is solely as a clip on.

 

[Enrique Blein]

Hi there...just curious about the Hot Mirror, is it something Red cameras need because of extra sensitivity to infrared light? I'm not really familiar with the fllter or the Misterium sensor (yet)...

 

[Steve Sherrick]

+1 on the obox filter knob issue, I just lost a ND .6 to that little flaw. Overall the Obox is a really nice matte box, I dropped the 15mm attachment and use is solely as a clip on.

Yeah, mod it so that it takes a longer screw and it should be okay. I'm hoping in future versions they opt for an easier knob.

 

[Glen Powell]

I have the O-Box, and recently noticed a mod that added a third filter tray - of course I made note and then completely forgot where. I really like the O-Box and all of the attachment points, but the small knobs are a PIA.

G.

 

[Cail Young]

Hi there...just curious about the Hot Mirror, is it something Red cameras need because of extra sensitivity to infrared light? I'm not really familiar with the fllter or the Misterium sensor (yet)...

It's more that most ND filters don't cut IR light. So you end up with a huge imbalance between visible and IR light, and the built in IR protection can't fix it.