Arri ff4 / ff5 question

[Ben Coughlan]

Hi all

I have a question regarding the ff4/ff5. Im looking into buying a follow focus for my set up but want it to be as versatile as possible.

At the moment it would be used across 2 main set ups. I have a Zeiss contax set that have been cine modded/leitaxed but we also hire in a lot of different lenses for different jobs (ultra primes, super speeds, kowas, alura zooms etc)

I understand the gearing ratios both the ff4 and ff5-hd (or ff5-cine that has the same gearing ratio as the ff4). Because of the short throws on the contax set the ft-5 hd would look like its the best option at the moment, as this would work well with these but also when we hire in cine lenses with a 360 degree focus range I could change the gear module to a 64 tooth gear that approximates the speed of the ff4 or ff5-cine. I understand all the limitations with this, not being able to get the gear under the lens and witness markings etc but as a happy medium, it does seem like a solution.

My question is, if I put a larger gear on the ff5-hd, this speeds it up to approximate the ff4 drive speed.... Can this go back the other way? i.e, If I buy an ff4 or ff5 cine, can I put a smaller gear module (35 tooth) on it to slow the speed down for easier use with the contax set? This is obviously reliant on the gear being able to reach the lens but would be a preferred option, rather than having a massive 64 tooth gear on the ff5-hd that will struggle on certain lenses.

I can see the 35 tooth module being sold in quite a few place but can't find out what its primary use is for over the more standard 45 tooth gear.

http://www.photocineshop.com/en/pro...5-tooth-0-8-metric-module-gear-117T02?cat=757

Cheers guys

 

[Jason Comparetto]

I would think that you can mess with the gears as much as you want as long as the pitch is correct, it should work like you want it to. You'll need to do some math to figure out what the right amount of teeth would be for your application. You could also add a larger diameter/teeth to your lens set, in case that helps

 

[Ben Coughlan]

Thanks for the reply Jason. Does anyone have an experience with using the ff5-cine with 35 tooth gear? I see a lot of people going the HD with 64 tooth gear route but not cine with 35 tooth, which leads me to believe it may not speed the gearing up enough to approximate the ff5-hd. (1 turn of the know equal to 1 turn of the gear)