Underwater photography is a scuba-based underwater sport governed by Confédération Mondiale des Activités Subaquatiques (CMAS) where teams of competitors using digital underwater camera systems all dive at the same saltwater ocean sites at the same time over a two-day period. The submitted digital images are then assessed and ranked by a jury using a maximum of five photographic categories as well as an overall score. The sport was developed prior to 1985 as a photographic film-based event and is currently mainly practised in non-English speaking countries.