But seriously, the difference in digital, it strikes me, is that if I set my 5dii to ISO 100, I know that is correct. I don't have to worry about figuring out whether a 5dii is really at ISO when I set it at ISO 100. Perhaps this thread is mis-titled, because I think I get the basic tenets of the ZS. It's more how I get to a place where I can use it. In other words, I think it's the generation of personal EI without access to a sensitrometer that has me confused. And that is where things seem different than digital. I am shooting FP4+, but is it really ISO 125 and how do I methodically go about figuring that out?
I can just start using the ZS and determine where to "place" Zone III and then after development at N determine whether or not there is sufficient detail in Zone III to be called Zone III. But that does not seem to be the way that most people go about this. Most seem to figure out your personal EI first, then figure out N, etc.
See what I am getting at?