Advice on motorising the zoom ring on Canon lenses

[naskies]

Hi everyone,

Just wondering if the handy robotics/mechatronics people here can give me some advice on how to motorise the zoom ring on Canon SLR lenses for software control? This is pretty much what I want to build:

http://www.youtube.com/watch?v=qF-5jP7__sI

The aim is to provide an additional degree of freedom / axis of movement for time lapse photography. I can program virtually any chip under the sun, but seriously struggle to even put two cogs together when it involves physical objects :rofl:

Presumably, I'd need:

* a motor of some sort... "servo"?
* a cog or two for the motor to make contact with the zoom ring
* some way of mounting the motor onto the lens with a secure contact
* microcontroller for software control of the motor
* battery / power source
* some way of connecting all the above together

Any advice on how to get started?


Thanks!

Dave

[cventer]

Dave,

Couple of exmples using robofous units

http://msfastro.net/articles/canon200mm_setup.html

http://www.skyandtelescope.com/howto/astrophotography/3305701.html?page=5&c=y

http://www.galaxyimages.com/focus.html

[naskies]

Thanks - it never occurred to me to use Robofocus units. The zoom ring tends to be much stiffer (more torque needed) than the focus ring on Canon lenses; I'm not sure if that will be an issue. The Robofocus is a bit more expensive than what I was hoping to spend... might have to look into jury rigging something equivalent from parts.