Underwater photography is taking pictures under water while diving, snorkeling or swimming. It is addressed for scientific purposes, for example in the field of underwater archeology, but also in photojournalism, artistic photography or amateur photography.
Compared to photography over water, underwater photography poses special challenges for the photographer and his equipment:
The photograph is not taken in the medium for which the photographic equipment and the film – or, for digital cameras, the CCD or CMOS sensor – is designed, but in the water. Compared to air, water has a higher refractive index (1.33) and a lower one than the windscreen of the underwater housing made of glass (1.45–2.14) or polycarbonate (1.585). This means that all objects behind planar glass or plastic panes are displayed somewhat larger and appear closer than they really are. This apparent extension of the focal length under water can be prevented by “dome ports” (also called “dome glass”) specially calculated for the lens used. In addition, depending on the depth of the water, water filters certain wavelengths of light more strongly than air, which can lead to a green or blue tint on underwater photographs.
Suspended substances in the water significantly limit the transparency of the water compared to air. Very good conditions under water allow visibility of 30 to 40 meters, only in extremely rare exceptions – such as springs – up to a maximum of 100 meters, usually 15 to 30 meters in many ocean waters. From a photographic point of view, poor transparency of the water means visibility ranges from less than ten meters to a few centimeters (zero vision).
The motifs also often represent a further major requirement for underwater photographers: fish or marine mammals are almost always in motion and therefore difficult to position and focus in the image. However, currents can also make it difficult to keep the camera still to the required extent.
And if you are interested in a special underwater photography course, we offer the Photo & Video course!