http://issuu.com/varis_photomedia/docs/digitalzonesystem-part-1/17?viewMode=presentation This is a must read for any digital photographer. Great information, a true translation of the traditional Zone System developed for film. This is the link to an index of more information by the same author, http://www.varis.com/pdf-tutorials.html
http://www.varis.com/video-tutorials/ The tutorials on this site are really great. The author is teaching us how to generate the very best image quality by using all the technological abilities of digital processing. Well worth the look.