Quote Originally Posted by baachitraka View Post
I presume it is one of the clever system devised by the master.
Actually it's the way all metering and exposure setting works. BTZS is just "packaged and sold as a system". It's worth every penny for many people, for others it's just another way of doing the same thing they are already doing.

Using an incident meter and say Ilford's directions is not that much different, it just doesn't give you directions on how to pick the EI, like BTZS does. The film, the processing, and the metering though are just keyed to industry standards rather than specific film testing.