Exposing Your Shots with DSLRs
THE ZONE SYSTEM, HISTOGRAMS, AND ISOS
One of the tools to shape the ratio of light and shadow revolves around the zone scale—an arbitrary scale indicating the tonal values from dark to light in an 11-step black–grey–white gradation, numbered 0–10 (0 = black; 10 = white; see Figure 3.1). Zones 0–3 represent black and deep shadow values (details and texture in an image can begin to be seen in zone 2, while 3 shows dark details and some texture, and 4 reveals landscape shadows and dark foliage). In addition, zones 4–6 represent face tones (from dark-skinned to Caucasian facial tones). The mid-gray of 5 represents brown skin tones and sky; this is also the value of an 18% gray card used for white balance. ...