The Beauty of Bokeh
Sharply focused images are considered essential for good underwater photography. An otherwise beautiful photo is spoiled if, say, the eye of a sea creature is out of focus. But the converse problem can occur; an otherwise beautiful photo can be spoiled because everything is in sharp focus, including the subject of the shot and the cluttered background. A sharply focused background can make the subject difficult to discern.
There are various ways of making the subject stand out from the background. One method involves bokeh, as illustrated in the images here, which were taken on dive trips around British Columbia.
Bokeh, derived from the Japanese word for blur, refers to the blurred background, which is attained by using a shallow depth of field, with either a telephoto lens or a macro lens. The latter was used for these images.
There are qualitative aspects to bokeh. “Bad bokeh” is when the blurred background is esthetically unpleasing or distracting. “Good bokeh” is esthetically pleasing and complements the subject of the photo; that is, the subject naturally seems to emerge from a softly blurred, complementary (non-jarring) background. The distinction between good and bad bokeh is difficult to put into words, but you can tell the difference when you see it.