Reading the histogram
For such a small, straightforward-looking thing, the histogram packs a lot of information in. Here’s how to decode what this graph is telling you about your exposures…
Camera’s tonal range 1
The horizontal axis represents the 256 brightness levels that the camera’s sensor can record, from 0 (pure black) on the left to
255 (pure white) on the right.
Scene’s tonal range 2
The width of the histogram represents the brightness range of the scene captured through the lens. If the histogram shape fits within the width of the graph, detail will be recorded throughout the image.
Shadows 3
The left side of the graph is where the darkest tones are registered.
Midtones 4
A mid-grey scene should show a peak in the centre.
Highlights 5
The right (bright) side of the graph is where the palest tones of your shot should be positioned.
Number of pixels 6
The histogram is actually a densely packed bar graph, with the height of each bar showing you how many pixels have been recorded at each level of brightness the image sensor is capable of capturing.
Close to the edge
If the histogram runs beyond the edge of the graph, you will lose detail in those parts of the image.
Tip of the iceberg
If the histogram peaks beyond the top of the graph, that just indicates a lot of pixels have recorded that brightness.