What time of the day is best for underwater photography?
Despite the prevailing rule of thumb for land photography, which indicates early morning or late in the afternoon as the best time for best results, noon offers the best lighting for underwater photography. The reason for this can be found in the light filtering properties of water. After a depth of only 5 meters, the rays of light passing through water have already noticeably lost some of their red spectrum. For that reason, it would be best to photograph during the time of day in which the light has the shortest distance to travel through the water till it reaches the lens of our camera. That would be when the sun is directly above us and generally speaking, between 11:00 AM and 2:00 PM.
Early mornings, twilight and night time offer unique opportunities with respect to artistic lighting and interesting subjects, but during these times - a good external flash system is recommended.