Subject: A Day Octopus (Octopus cyanea) changes rapidly of colour. Metachrosis is the physical ability to change colour and it is often used as a type of camouflage. Chromatophores are pigment-containing and light-reflecting cells that allow a rapid colour change. Pigment granules are enclosed in an elastic sac situated inside the chromatophores of the octopus. To change colour the animal distorts the form or size of this granules-containing sac by muscular contraction.
Technique: Position yourself lower than your subject and try if possible to get some of the ocean’s blue in the background… let the camera roll and anticipate, only this way you catch any action. It may take several minutes of filming before anything happens but if you wait long enough you will be rewarded with some nice images. The non-interesting sections or parts without any action are easily removed once you have transferred the images on your computer.