Underwater Photography Glossary

The histogram is a graph that allows you to judge the exposure and how light is distributed acorss the tonal range of your image.. There are 256 tones in a histogram, from black (0) to white (255). Blank spaces in your histogram equate to missing tones. The histogram can be used while shooting to identify when your images are being underexposed, overexposed, or suffer from a lack of or excessive amount of contrast.