http://www.youtube.com/watch?v=uXpLIT_GN6Q&feature=player_embedded#!

After building himself a camera dolly, Adi Soffer found it was difficult to manipulate the focus control of the camera, so he built this focus pulling system around an Arduino and a servo-actuated lens ring. Thankfully, he documented everything (documentation is everything, y’all) and shared it with the world. You can read parts 1, 2, 3, 4, and 5 of his build adventure on his blog. Of the last part, he writes:

First of all I have ordered some Atmega chips to create a smaller, more professional version, and am also working on a more aesthetic and handy configuration for the whole thing. I have a most generous friend who’s helping me out with designing a custom box for the whole thing – actually something that is a far cry from the “box” I’ve used for now. Check out her blog and her beautiful works here.

I’m also doing some research about stepper motors which are more silent and could have a higher resolution. Although “staircase” effect is not visible with this particular lens, I think it may pop up later on with different lenses and slower pulling. Of course stepper motors are a whole different ball game in terms of coding so I’m really trying to figure out as much as I can before jumping in. Any thoughts are more than welcome.

Nice job, Adi — excellent documentation and cool project!