Editing Zone System (section)

==== Histograms ====

Most high-end digital cameras allow viewing a [[image histogram|histogram]] of the tonal distribution of the captured image. This histogram, which shows the concentration of tones, running from dark on the left to light on the right, can be used to judge whether a full tonal range has been captured, or whether the exposure should be adjusted, such as by changing the [[exposure time]], lens [[aperture]], or [[ISO speed]], to ensure a tonally rich starting image.<ref name="Histograms and the Zone System">[http://www.illustratedphotography.com/basic-photography/zone-system-histograms Discussion on how histograms can be used to implement the Zone System in digital photography] ([https://web.archive.org/web/20120501173208/http://www.illustratedphotography.com/basic-photography/zone-system-histograms archived 2012-05-01])</ref> A technique called [[ETTR]] (exposing to the right) based on histogram reading rather than exposure metering is shown to be more appropriate for digital sensors to extract more visual information out of them for further processing in editing.