"Photography is light. Light is photography."
Keep repeating this until it's stuck in your head like a bad sitcom theme. Sing it to a catchy tune if you have to, but whatever the case...remember this.
Controlling light, playing with light, fiddling with light, manipulating light...that's pretty much 99% of photography, once you get past the fundamentals of how to use your gear.
For instance, you've probably seen a bajillion images of transparent shrimp on anemones. They're really pretty, and I must confess to having taken my fair share of normal photos of these little gems. But again...to be unique...here's something different I tried with one such shrimp in Ambon:
I like this image. You may or may not. But you have to agree that it's different from the usual manner in which these little crustaceans are portrayed.
So how'd I do it?
It was mid-day, about 15m down, with this two-centimetre-long shrimp sitting on a rock next to its host anemone...otherwise a pretty nondescript scene that everyone else swam right by.
Careful placement of a strobe slightly above and behind as the hard primary light + a soft fill at about three stops under from the front left = emphasis on the transparent body and intricate fuzz on the rock.
I'd like to say that I nailed this right away, but it took a dozen tries or so, primarily because shrimp like these don't sit still. This one moved continuously, which meant the lighting changed continuously, which meant I grumbled muffled expletives continuously.
Note the pile of eggs in its belly. Yup, this one's a proud mommy shrimp.
And here's another shrimp everyone else swooped past...this one photographed with a single strobe to the extreme right. Had I used the normal one-strobe-to-the-right-one-to-the-left-and-blast-away approach, this image would've been really cluttered, as the background was filled with rocks, reef, coral...stuff.
The effect is more subtle in this image than in the top picture, but the common theme is that selective lighting makes the shot.
Selective lighting isn't easy, but it can often make the difference between a humdrum picture and one that stands apart from the crowd.