Limited Depth of Field composition is a very effective and stunning form of photography when it’s done well. Although it does look complicated, it’s actually a very easy technique to setup. Here are a few steps to follow to learn “How To” take macro underwater photos with great bokeh.
Choose an fstop between 1.8 and 8, the more open the f-stop the less DOF there is
Strobe strength has to be at a very low power or else utilize TTL
Choose subject accordingly, a flat subject will not “show off” the bokeh properly, therefore subject selection is key
Don’t forget the background, a colourful background will enhance the “out of focus” aspect of the background itself. Bright colours work well
Use a fast shutter speed: the DOF is very narrow so any little movements from the camera will be multiplied in the photo, using a fast shutter speed helps
Use manual focus or focus lock, keeping a very narrow area of a macro image is hard to do, using manual focus helps so that the lens does not “hunt” while focusing
That’s it, very simple yet effective hints for trying this fun form of underwater photography.