The Zone System was created by Ansel Adams to teach B&W exposure technique. It is very simple and makes a lot of sense. It works best for sheet film because that allows contrast control via development of individual exposures. I use the concepts consistently and intuitively with my 6x6 Rolleiflex TLR. There is a book by Adams called "The Negative" that explains the Zone System. It is easy reading.(posted 8696 days ago)