Glossary
Zone system
Also called: zones
A way of placing tones on a 0 through 10 scale, devised by Ansel Adams.
Adams split the tonal range of a print into eleven zones. Zone 0 is paper-base black, Zone 10 is film-base white, Zone 5 is middle grey, the tone every meter is calibrated to. The real idea is placement: you pick a tone in the scene and decide which zone you want it to land on, then set exposure to put it there. Spot-meter your subject's face, place it on Zone 6. Done. The app's zone calculator and AR overlay do the math, tap any spot to see where that tone falls.
