Working follow focus test setup!

Yes! It works!

It works a little better than the video shows, but it's a little too noisy right now, and still has some kinks to be ironed out.

Video with the Canon M500

Stepper motor success at long last!

Finally!
 I now have my Arduino driving the stepper motor!
This is the motor:

Here is the driver circuit:

And here's the whole test setup:

(As you may know, I'm not especially known for neatness, as long as it works I'm happy!)

Here's the oscilloscope I'm using:

And finally, proof that it really does work:

(apologies for the poor quality)

That's it! I'll keep working on it, and hopefully add a position control soon!