DSLRUsers.com

... Obsolete ...

Adam,

I don't control the zoom ring with an R/C servo but I do control it with a knob on my underwater housing. It may be worth looking at the mechanisms used in Ikelite and other brands of housings. Basically, a clamp fits over the zoom ring and then a sleeve fits over that. The sleeve fits into some gears which you could attach to a servo.

Here are the instructions that come with my housing:
http://www.ikelite.com/downloads/instru ... Sleeve.pdf

I would look towards the Meccano type of gear.

A lot of R/C cars are belt drive, Yokomo and Losi are 2 brand names you may want to try either on Ebay or your local shop.

Cheers

try http://www.smallparts.com.au/

they have quite a variety 'vee' belts and 'timing' belts which may help you out - download their catalogue and it has all the pictures for quick reference. They are also aussie. hth