Where do I position my strobes? This is one of the most common questions asked.  There is no right or wrong answer as playing with light gives you different effects depending on what you are looking for.

Typically, for macro you can get away with one strobe positioned over the top of the camera, although many people use two to create shadows or other effects.  For wide angle, positioning is much more critical and you really need two strobes.  Either way, the closer you get to your subject the better as even the most powerful strobes are ineffective when you’re a couple of metres away.

8 Easy Tips for Lighting It Right

  1. Always keep your strobes pointed forward, not inward.
  2. As you get closer to a subject, bring the strobes closer to the housing. (above, left)
  3. As you get farther away, push them out wider. (above, right)
  4. If you see backscatter while reviewing your image, push the strobes out wider for your next shot.
  5. Reposition your strobe if it is lighting an ugly area of the reef.
  6. If one strobe is significantly closer than the other, turn down the intensity of the closer strobe to avoid blowing out the exposure.
  7. For wide-angle vertical shots, try turning off one strobe and just use the one on top.
  8. For wide-angle shots with a wall on one side, position one strobe on top and another on the blue-water side.

Here’s a couple of good articles to help you:

http://www.backscatter.com/learn/article/article.php?ID=186

http://www.seaandsea.jp/compact/p07.html