Roger Hicks
Veteran
Well, EI anyway. Determining ISO is beyond most people, including me. If you can do it, I salute you.Roger it is relevant because to do the zone system properly you need consistency in all aspects of the process and that all starts with the proper ASA/ISO. It is like building on a solid foundation and the tests all do away with all the variances such as lens manufacturing and variances in shutter speeds. It does work and did work for Adams and other B&W zone system photographers.
It won't make you a great landscape photographer and I tend to now be more like Winogrand/Eisenstadt street shooter. I sometimes don't even meter because I know that in the summer bright sun at 1600 ISO that my exposure will be f/11 at 1/2000 and in the hard shadow it will be f/8 at 1/1000 or there about.
But if I were to ever start shooting large format landscapes again I would use the zone system. I would redo all the tests for the camera and lenses I would be using but thats me. Flavor to test but it does work. Without the tests how do you know what the proper ASA is for the camera and lens you are using? How do you know the normal dev time is for the film/dev combo or the way you agitate or N -1 neg development is? Do you have to do it? No. It can give the photographer more control over the entire process and is a way to consistently visualize the way a final print will look like at the moment of exposure.
In the way I work today I don't use it but those sensitivities are all part of who Im as a photographer. It is there. When I was still shooting 35mm B&W film on the streets I did similar to what you say in #3.
Many greats like Winogrand and Eisenstadt didn't even use meters. They relied on their experience and knowledge. Weston, Adams and many of the f/64 crowd used the zone system. Many different ways to work but understanding how the process works is such valuable knowledge as well as knowing what film and dev combos work for the way you need your final images to be what ever road you take.
Basically, ISO is a combination of opinion and arbitrary choice. EI is the same only more so. The only question is what degree of (sometimes false) precision you seek.
What do you LOSE by giving an extra stop, or even two stops, of exposure with large format? Nothing, as long as you are (a) consistent and (b) happy with the result.
Cheers,
R.