Ansel Adams

            
             Ansel Adams created an approach to photography that couples the visualization of the subject as a photograph with the appropriate exposure and development controls.
             The zone system is a relatively advanced approach to the exact science of sensitometry and practical applications of exposure theory. To understand this it is important to aware of a few basic facts of photography. Ansel Adams believes it was fundamental to have some idea of what your picture is to be - not only compositionally, but in terms of tone values and contrasts in relation to our subject and how we feel about our subject.
             He suggested that just because the subject is of low or high contrast does not mean our picture must be flat or harsh. The problem he believed was one of visualizing the desired print, and then exposing and developing to get a negative which will yield such a print without complex manipulations.
             A negative produced by applying the Zone system has a scale in which - for any given film and developer - shadow details, midtones, and highlight values each fall within narrowly defined ranges of density that, in turn print as visualized subject tone values.
             The ultimate goal of the Zone system is not to create a perfect' negative from which a perfect' print can be made without dodging, burning-in, etc. What the Zone system enables you t o create is a perfect negative which simply embodies the right amount of negative density and contrast to allow you to produce an expressive print with little effort and no darkroom magic.
             Part of the basis of the Zone system is a grey scale in which there is a continuous transition from black to white that is arbitrarily divided into ten steps, or zones. Exposure Zone 0 translates to maximum black in a print and exposure Zone IX corresponds to maximum white, and Zone V is roughly the equivalent to middle grey.
             To utilise the zone system according to Ansel Adams, the photographer needs to imagine the image as approximate print tones (in terms of the grey scale) that correspond to the subject's various luminance values.