focus gear/modul ff4?!

[Brain S]

What focus gear/modul for the arri ff4
do i need for the red 18-85, 18-50mm
and the primes?!

 

[Jeff Kilgroe]

The 0.8 pitch 43-tooth cine gear. Arri #381574 There are also 35 and 64 tooth variants of the 0.8 cine gears to offer different gear ratios (speeds). The 35-tooth is about 82% as fast as the 43 tooth. The 43 tooth is about 70% as fast as the 64 tooth.

 

[Brain S]

ok thx

 

[Adrian T.]

The 64 tooth gear won't work with the 18-85 because of the large lens diameter.

 

[Jeff Kilgroe]

Adrian, are you sure about that? I don't own the 18-85 and the large gear to test together... However, I use the FF-4 with the standard 43 tooth gear on the Cooke 18-100, which is larger in diameter than the RED 18-85 and there's room to spare.

 

[Adrian T.]

Adrian, are you sure about that? I don't own the 18-85 and the large gear to test together... However, I use the FF-4 with the standard 43 tooth gear on the Cooke 18-100, which is larger in diameter than the RED 18-85 and there's room to spare.

Yes, I'm sure. I tried. I will try to take a picture and post it here.

 

[Adrian T.]

Ok, the main problem is that the FF4 can only be placed where the gap is right in front of the focus drive gear. The lens diameter is too large on both sides of the gap. (see picture #1)

Now the FF gear must be mounted in the front position in order to work. The rear position is too far back for the lens drive gear. But the 64 tooth gear is simply too large for the front position. (see picture #2)

If there's any solution to this problem I'd be glad to hear it. I couldn't find any.

 

[Stephen Lovett]

Me too

Me too

The only solution I've found is what Adrian is doing.

And frankly it's a pita, but it does work.

I've included a photo of that might help quantify the clearances.

I'd love to know if the larger gears will actually fit.

Hope this helps.

Steve