Does anyone have the measurement around the focus ring of the EF-S 17-55mm f/2.8 IS? I want to purchase the cavision gear ring for this lens since I'll be renting it and eventually buying it, but don't know the focus ring measurement. Thanks!

245mm around and about a 80mm diameter.

Thanks, Nigel! Do you own it? How's it been for you on the 7d?

Yes. I wanted one lens for documentary (film) content and this works well. I do often find myself wanting to use something longer but not at the expense of the wides. If you are handheld and zoomed in the IS makes a difference.

I use the RedRock lens gears and they work well.

Stuff shot with this lens only with the Fader ND here - http://vimeo.com/user712613/albums

Are you using the gears with another brand of focus pull or are you using the redrock focus pull too?

I'm using the Micro Follow Focus v2 and really like it. I tried a few out and for the money this is a solid piece of kit which feels like it will be around for many years. I am hard on my equipment.

In case anyone finds this thread in a search for what Cavision focus gear ring to use with the Canon EF-S 17-55mm f/2.8 IS USM Zoom Lens, it's the RFGR80 ring.

In addition to the 17-55, I also have a :
Tokina 11-16 f2.8
Canon 70-200 f2.8 is
Canon 50mm f 1.44
Canon 18-1354 kit lens

Anyone know their sizes or redrock part number for these?

I bought 6 lens gears from them when I firsrt ghot my Letus Extreme, and have been very happy with them. Not cheap, though.
Thanks
Bruce Yarock