Absorption  The blue, filtering effect of sunlight. Water absorbs the colours of the spectrum selectively until, at depths of around 20—25 m, only tones of blue and green remain.

AE lock  (AE-L, Auto Exposure Lock) This enables you to take a light-meter reading from part of an image and then hold that setting while you compose the picture.

AF lock  (AF-L, Auto Focus Lock) This enables you to lock an auto focus lens in its present focus setting and then hold that setting while you recompose the picture.

Ambient light  (also referred to as natural light) The light from the sun which is available underwater.

Angle of view  The extent of the view taken in by the lens, which varies with focal length for any particular format size. The angle ...

Get The Underwater Photographer, 4th Edition now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.