Follow focus for zoom control
 

Not sure if this has been discussed already but has anyone tried using a follow focus rig for zoom control? I'm not thinking so much about the usefulness of zooming while recording but more so the overall ease adjusting focal length in the field.

If you have, did you also try to have another FF doing focus control at the same time? Can two FFs even fit at the same time?

I have tested my DIY gearless ff on my 80-200 zoom ring instead of the focus ring. It will give a smooth turn BUT the problem is most zooms arent parafocal.

Usually, we "traditionally" zoom in focus, and zoom out. And know that focus stays. This is not the case with still camera lenses.

Heres my ff.

DIY Gearless Follow Focus Test http://exposureroom.com/getassetthum...89b3e4&size=sm

Just found this page: Basic Mini Single Wheel Follow Focus - Dual Setup

Looks like a great way to go but I'm still wondering if two FFs could be used on the same side. Seems like this would be even more convenient because the right hand could stay on the hand grip and recording can continue uninterrupted (thinking about event and guerilla type shooting).

I'm thinking the main factor is having enough space for both wheels. I' suppose it depends on the distance between the focus and zoom rings on a particular lens and on the size of the wheel. Any ideas on which model might work best? Cavision, Chrosziel, Arri, or others?

I'm aware of the parafocal issue but I can just imagine being able to adjust zoom and then quickly refocus because the other wheel would already be right there by your hand. Having the second wheel on the other side doesn't seem like a good solution to me for this reason.

Check this, he has it mounted on one side,

iDC Photo Store - Specialty gear for the photographer

That's definitely along the line of what I'm taking about. However, can it only be used with these lenses:

EF 24-70mm f2.8L USM
EF 28-70mm f2.8L USM
EF 24-105mm f4L IS USM
EF 70-200mm f2.8L USM
EF 70-200mm f2.8L IS USM
EF 70-200mm f4L USM
EF 70-200mm f4L IS USM

I'd really like to have this capability on the 16-35 or 17-55. Also, I'm not too sure about the gearless design. Any experience with that?

No experience with that product. Only with mine where Its tricky to use on old lenses with the rubber rings already brittle and smooth, it works with focus and zoom rings with rubber rings that still "stick" or "grip" for lack of the proper word.

In cases where the focus ring don't have "traction" anymore, i added a belt that provided the traction for the gearless follow focus to "hold" on to.

We do have a few folks using the Durus Focus Gear Lever on their zoom rings. It essentially provides an outboard handle to whip zoom etc.

Cheers,
Dennis Wood
www.cinevate.com

I am a complete newbie trying to learn some stuff about the DSLR video features. So there are no lenses that would allow for having a subject consistently in focus?

I'm thinking more along the lines of sports.

Very expensive cinema lenses (think $10k on the low end).