Redrock MB Problem

[Ryan Nichols]

I just got the mattebox today. I’m using it on the RPZ 18-85 and if you go out past 25mm you can see really bad vignetting. If you get out to around 18-19 you can see the entire inside of the box. Is there something I’m doing wrong or is it the focal length to wide for this box/lens front diameter too large?

Thanks!

 

[Terry VerHaar]

Just curious - is this with the side wings on or off?

EDIT: Do you maybe have the mattebox too far from the lens? Can you bring it in closer?

 

[Ryan Nichols]

It’s about a millimeter maybe two from the lens. The lens is too large for the donut to fit properly. I could scoot it closer but its very tight on the rods even when loosened and I’m afraid the tension will break and send it flying into the lens. This is with the wings on, but they are open fairly wide. At 18mm you can literally see most of the inside of the mattebox with some level of detail.

 

[Frank Martin]

Hey Ryan
We lightly sanded the the plastic back
of the matte-box in order to enlarge the hole.
This way the RPZ 18-85 will slide through the hole.
You have some room before first filter
stage . Slide mattebox over lens until
it does not vignette . It is just barely
out of lookaround @ 18mm. We used a
Dremel tool with a sanding bit but you
Could wrap a stick w/200,400 grit paper
and just lightly go round and round
until lens fits through back of mattebox

 

[Ryan Nichols]

BEAUTIFUL!! Thank you! I’ll try this right now.

 

[Ryan Nichols]

What follow focus do you use? The RPZ is also to wide for the one I have...

 

[Ryan Nichols]

I’m kinda nervous about sanding it..do you have a picture I can look at?

 

[Frank Martin]

Mattebox is on rental. Just do it by hand
and make alternating 180• strokes.
The plastic is thin and easily sanded.
You just don't want to make an oblong
hole. You can use the lens cap and a grease
pencil to give yourself visual guide.
Package comes back later in week if
you can wait but your gonna have to
bite bullet at some point. Just go slow
and easy. But I'll be happy to show you
a picture if you need. We made it so the
Lens just fits without scratching paint.
We also replaced bracket that goes on
19mm rods, I apologize but I just can't
Remember who machined it for us,
Maybe Matt Duclos but I'm drawing a blank
Maybe someone can chime in. It is a much
sturdier bracket

 

[Frank Martin]

We use the O'connor FF-1. It's
very well made and has a thin profile

 

[Ryan Nichols]

Are you talking about the sawing away arm? Because that feels pretty sturdy on mine.

 

[Frank Martin]

Well since hinged mechanism is a separate
Part it seems more like a mounting bracket/arm
2-19mm holes on one side 2 smaller diameter
holes to mount on the swing away bracket
On the other. Whatever the correct term
we found that the bracket from Redrock
flexed a little when we had a full compliment
Of filters . We felt that since the consiquence
would be scratching the lens, it was worth upgrade.

 

[Ryan Nichols]

Interesting. Ill have to look at that more closely. How old is your box? There might have been a redesign going on.

 

[Jeff Kilgroe]

RedRock supposedly re-designed this mattebox to fit the 143+mm diameter of the 18-85. You should not have to sand anything, I would contact RedRock. ...Or maybe they never went through with the re-design or change in manufacturing. Who knows.

Anyway, the problem is most definitely mattebox position as others have pointed out. The RRMB should be good at 4K on the RED One at 18mm and longer focal lengths. It might also work at 16mm, but I did not test that myself. I haven't owned or used at RedRock Mattebox in quite some time now.

 

[Ryan Lalonde]

Has anyone adapted their RRMB to use 138mm filters? I assumed it would make lenses like this unusable, so i've held off...but its pretty hard to rent a mattebox that doesn't use 138mm filters...it's also pretty hard to rent a mattebox thats redrock

 

[John Saunders]

Just thought I would throw this out there. At least in my RR matte box there is a plastic rectangular ring that is removable for wider lenses. It took me a while to realize that it was removable. Don't know if that's what the problem is but thought I would chime in.

 

[Shane Kelly]

Here's how I modified my rr mb.
It now has a 80mm bellows back that will take 138mm and a red 19mm rods mount so that it will slide on a dovetail. I don't use the red rock much anymore as I've gone to an arri mmb-1 but it served it's purpose for a long time. If anyone wants it, I'm open to offers.

 

[Ryan Nichols]

Well I got it to fit just fine but now I’m looking at a follow focus for it. It’s too big for the one that I have now and I don’t thing I’ll be able to use a dual wheel with it and the 18-85 because the swing away hinge is sitting over where the right side wheel would be. Can’t anyone shed some insight into this?