#4. Ansel Adams’ Zones
True or False?
Ansel Adams’ zones are defined by the whole-stop settings of traditional cameras and cannot be used with fractional-stop settings of modern cameras.
Ansel Adams’ created his zones and his Zone System (with Fred Archer) using a traditional camera with shutter speed and aperture number (f/number) settings limited to whole stops. His adjacent zones are separated by wholes stops. A photographer changes zones by adjusting either the shutter speed or the aperture number by whole stops. Adams created and identified his eleven zones, 0 through XI, in this way.
Modern cameras offer one-half and one-third stop settings for the shutter speed and the aperture number.
The modern photographer can ignore these fractional-stop settings and use Adams’ original zones, or the modern photographer can refine his or her thinking and use two or three times as many (fractional or sub) zones.
Adam’s numbering of the zones no longer makes sense, however, because there are more zones and because solid-state (“digital”) and other emulsion media have something other than Adams’ nine usable zones. It makes more sense to identify the zones starting with zero in the middle (midtone) of the exposure range and working outwards.
… -1.33, -1.00, -0.67, -0.33, 0, +0.33, +0.67 … for one-third-stop zones
The exposure compensation becomes the perfect variable for identifying these new zones. All the photographer has to do is to figure out what to do with them.
The use of the exposure compensation to identify all these fractional-stop zones around the midtone photosensitive exposure is discussed in the Photographic Exposure Calculations and Camera Operation.
Copyright 2008 Michael G. Prais, Ph.D.
For a readable but in-depth analysis of this concept along with many other concepts associated with photographic exposure, take a look at the book Photographic Exposure Calculations and Camera Operation. This book provides insight into the equations that govern exposure, exposure meters, photosensitive arrays (both solid-state and emulsion) and the Zone System as well as concepts associated with resolution, dynamic range, and depth of field.
The book is available through Amazon.com (ISBN 978-1-4392-0641-6) where you can Search Inside!™.
Check http://michaelprais.info under Photography for the table of contents, an extensive list of the topics and subtopics covered, the preface describing the purpose of the book, and a diagram central to the concepts in the book.
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