Slowing down FF gear ratio

[Jonas Klittmark]

Hey guys,

I'm looking at getting a new FF since I'm fed up with my Redrock v2.

With the new one, I would like to be able to slow down the gear ratio so that I can get better precision with short focus travel lenses such as the Zeiss 35 f/2. (Don't even get me started on auto focus lenses.) Am I correct that adding a large diameter gear ring to the lens and a small diameter drive gear on the follow focus should do the trick?

For the follow focus, it would be ideal to have drive gears of different sizes to switch between and match the lens I'm using at the moment. For example, the ZF 100mm f/2 has 335 degrees of travel whereas the 35mm has only 120 degrees. I would want to use a normal/large diameter drive gear for the 100mm and a small for the 35mm.

E.g. it seems the Chrosziel 206 has 3 differently sized drive gears that are all .8 pitch so maybe this would work?

Is anyone doing this? What's your setup?

Interestingly, Letus decided to go the other way and speed up the gear ratio to 1:2. What I'm looking for is the exact opposite, like 2:1 (inpututput).

Cheers
Jonas

 

[Julio Quintana]

Try the O'Connor mini follow focus. It is designed for still lenses.

 

[Per Kreuger]

Or the Arri MFF-2 with a two speed knob

http://www.arri.com/camera/professional_camera_accessories/follow_focus/mini_follow_focus_mff_1.html

 

[Jonas Klittmark]

Or the Arri MFF-2 with a two speed knob

http://www.arri.com/camera/professional_camera_accessories/follow_focus/mini_follow_focus_mff_1.html

It looks great but the two different gear ratios they have seem to be 1:1 and 1:2, meaning either normal or fast. I would like normal and slow... I'm so surprised that nobody has caught onto this yet. With so many people using still lenses that have decent optics but are close to impossible to pull focus with, it seems like a natural mitigating factor to at least slow the gear ratio down.

 

[Jonas Klittmark]

Try the O'Connor mini follow focus. It is designed for still lenses.

Looks pretty awesome. The only downside is that for those few lenses of mine that actually have a good amount of travel, like the 335 degree Zeiss ZF 100, this could start to get painfully slow. I'm beginning to think I need a solution with replaceable drive gears...

 

[Igor Ryabchuk]

I'm using Letus FF, it comes with 2:1 gear ratio, so only "slow" mode for me, but I'm quite happy with it - minimal backlash, nicely built.

 

[Jonas Klittmark]

I'm using Letus FF, it comes with 2:1 gear ratio, so only "slow" mode for me, but I'm quite happy with it - minimal backlash, nicely built.

On their web site it is listed as 1:2, meaning it is accelerating and making it faster. To get to the bottom of this, could you count how many teeth of movement on the lens one full turn on the focus knob results in?

 

[Andreas Mendritzki]

You could try using an Arri MFF-2 with an FF-3 two speed knob.

 

[Rob Castiglione]

I have exactly the Chrosziel 206 Studio (video version) plus different gear drives for exactly this purpose. Apart from being a precision piece of engineering and having a nice feel it certainly works to increase the focus throw on still lenses.

 

[Nick Junkersfeld]

I have a Shoot 35 FF, they offer additional gears from 32-59 tooth, it comes with a 40-tooth drive gear. I just received a 34-tooth for a particular zoom I have, it made a noticeable difference by extending the focus-throw a bit. It's a very basic FF, but it's feel is on par with anything this side of Arri (the all metal gearbox makes a huge difference) and the adjustable back-lash is a great feature. Btw, I had a Redrock V2 like yourself, the Shoot35 is in a different league feel-wise.

 

[John Desay]

Hey Nick,

Can the Shoot 35 be used with still lenses also....looks nice for the price!

 

[Jonas Klittmark]

I have exactly the Chrosziel 206 Studio (video version) plus different gear drives for exactly this purpose. Apart from being a precision piece of engineering and having a nice feel it certainly works to increase the focus throw on still lenses.

That's awesome. I'm keeping an eye on eBay... It's too expensive new for me but this would be the ideal FF.

 

[Jonas Klittmark]

I have a Shoot 35 FF, they offer additional gears from 32-59 tooth, it comes with a 40-tooth drive gear. I just received a 34-tooth for a particular zoom I have, it made a noticeable difference by extending the focus-throw a bit. It's a very basic FF, but it's feel is on par with anything this side of Arri (the all metal gearbox makes a huge difference) and the adjustable back-lash is a great feature. Btw, I had a Redrock V2 like yourself, the Shoot35 is in a different league feel-wise.

Interesting. I'm having our friends at Lanparte create a new (!), smaller drive gear for me to work with their FF that has been getting a lot of praise. If this custom project falls through, I'll probably give the Shoot35 a try then.

Thanks everyone for the help on this. I will update the thread when I feel like I have completely solved the problem. I am already in much better shape by using the Cinevate gear rings. They have a very large diameter, which slows down the ratio from that end. They also have 360 degrees of teeth which is awesome. If anyone is looking for gears for still lenses with short throw, these are the best I have found by far.

 

[Nick Junkersfeld]

Hey Nick,

Can the Shoot 35 be used with still lenses also....looks nice for the price!

The Shoot35 is designed for still lenses first and foremost from what I can tell, but because you can add a fairly large-tooth gear, it's useful for long-throw cine lenses too.

 

[Luke Grandmont]

Interesting. I'm having our friends at Lanparte create a new (!), smaller drive gear for me to work with their FF that has been getting a lot of praise. If this custom project falls through, I'll probably give the Shoot35 a try then.

Thanks everyone for the help on this. I will update the thread when I feel like I have completely solved the problem. I am already in much better shape by using the Cinevate gear rings. They have a very large diameter, which slows down the ratio from that end. They also have 360 degrees of teeth which is awesome. If anyone is looking for gears for still lenses with short throw, these are the best I have found by far.

Glad to hear Jonas! If you didn't see it already, we also have a larger Drive gear for the Durus as well; Large Durus Drive Gear