DC controlled camera lenses are basically milliampmeters.

A mechanism similar to a meter movement opens the iris against
a closing spring force. The 'drive' is a variable CURRENT to
make the circuitry simple and not dependent on absolute coil resistance.
And the magnetic force is a function of CURRENT since the coil is
quite inductive.
The 'control' winding is used as velocity feedback to damp the
coil motion, by reducing the drive current as the iris moves, to
prevent overshoot.

You can dive the lens using a variable voltage source with a current limiting
resistor into the 'drive' terminals.
Hang a scope on the 'control' leads to see the back EMF the moving coil
generates. If you short out the control winding you get maximum damping,
which is probably what you want for your basic voltage control.

Robert


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