This short audioblog (under 5 minutes) will give all photographers who want better control over their exposure when using black and white roll films a quick and easy working solution: The 5 Minute Zone System! This is not your grandfather’s full-bore Zone System but rather a user-friendly method for predictable, repeatable results! Just click on the audio link and give it a listen… Viva la Revolution!!
More info on the FULL-BORE Zone System: Click Here!
Figital Revolution 
Good post, just ran across it as I was about to develop my first few rolls in diafine.
So, you are saying set the camera ISO at 100, but meter for 800.. or I suppose if I don’t have a spot meter, set the camera to spot meter mode, set ISO to 800, which would be 200 for what the film is rated for diafine, plus two stops to hit zone III.
Thanks, really enjoy reading, nice combo of tech + art.
Dan
The asa or EI all depend on the film speed used but say you have a 100 speed film, set your camera to 400 and expose using a spot meter in or out of camera on the shadow area of the subject…this 2 stop underexposure will place the Zone 5 which the meter reads to a Zone 3 with is the ideal placement for your full shadow region…zone 2 is also possible and thus an EI of 800 depending on your film due to the open nature of shadows using Diafine developer.
Viva la Revolution-
Stephen