I think both of us are assuming that the scene EV would be the same for any specific comparison.
I think Chan is suggesting that in the digital realm the ISO setting is not necessarily considered a tweak, that it has become a primary adjustment that can be used in place of/instead of time and aperture.
I'm suggesting that we can do essentially the same thing with film, as long as we consider the adjustments that can be made in the darkroom.
XP2 is a great example, the following was copied from the Ilford spec sheet:
In this example essentially only the exposure of the paper need be adjusted and the ISO/EI can be allowed vary from frame to frame. Using ISO/EI as a primary adjustment allows a very different way of shooting than Adams used and taught. Yes the technical look of the print may change with the change in exposure but, the creative use; the ability to maintain a given DOF and given amount of motion blur across a range of EV's is very freeing.CHOOSING THE RIGHT FILM SPEED FOR THE JOB
Best overall quality EI 400/27
Finer grain (with easy printing) EI 200/24
Finest grain (but with denser negatives) EI 50/18
No matter which film speed is chosen, standard C41 processing is recommended.
This same principle (ISO/EI being adjusted) is used in disposable cameras, Holga's, blah, blah, blah...
In my experience normal B&W films can be used the same way.