Quote Originally Posted by m_c View Post
Main thing is the carriage pre-load. Your probably want medium or high pre-load to eliminate any wobble. Low pre-load (or just cheap rails in general) will likely develop play quite quickly.
The screw will be vertical otherwise I would belt drive it, I think that would be easier to make work in a tight package, ballscrew + rail(s) takes quite a bit of space obviously

I'd use cheap Chinese clone rails, it's just a camera it will never see any real torque in it's life