What does a histogram display in photography?

A histogram in photography is a graphical representation that illustrates the tonal values and distribution of light in an image. It provides insight into how the tones range from dark to light, essentially showing the number of pixels at each brightness level from black (0) to white (255).

By analyzing a histogram, photographers can assess whether their image is properly exposed, underexposed, or overexposed. For instance, if a significant amount of data is clustered at the dark end of the histogram, it indicates that the image may be underexposed, whereas data concentrated at the bright end suggests overexposure. A well-balanced histogram often indicates a full range of tones, which is desirable for a well-exposed photograph. This information is critical for making adjustments to exposure settings in post-processing or when taking the shot.

While the other choices mention aspects of photography, they do not accurately describe the primary function of a histogram. It does not convey exposure settings, color balance, or image dimensions directly; instead, it focuses solely on the tonal representation of light within the image.