The histogram display can provide a useful guide for setting exposures because its shape reflects the tonal distribution in your subject.

When the graph encompasses the entire scale without showing high peaks at either end, the photograph has recorded the full subject tonal range and highlight and shadow areas should contain detail.

To avoid blown-out highlights, make sure the graph does not build up at the right hand end of the scale. To avoid blocked-up shadows, try to keep the graph low at the left hand end of the scale.


In this image, the subject tones are skewed towards darker values, as indicated by the left-biased distribution on the graph.


The histogram for this image, which has a limited brightness range, shows subject tones are evenly distributed around the middle of the brightness scale.


The predominance of light tones pushes the histogram for this image strongly to the right end of the graph.

Article by Margaret Brown – see Margaret’s photography pocket guides  

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