A note of possible interest for this crowd: all these motor types are open loop, so you can't actually command a specific state with any accuracy / repeatability. In other words, if you send a signal to the lens to focus at, say, 3m, it won't necessarily be in exactly the same state as the next time you focus at 3m.
This is why camera calibration can be tricky, and you often don't want to touch the cameras after you've done a calibration pass.
This is why camera calibration can be tricky, and you often don't want to touch the cameras after you've done a calibration pass.