Very nice shots Marty, you must be rapt with that lens.
I will admit to not understanding the "science" of underwater photography although we have been snorkelling and used a Canon Powershot with underwater housing.

I wanted something that was better than a disposable but without the risk of exposing the SLRs to ruination ;-)
It is an amazing world down there.

Is it the use of strobes that compensates for the normal blue/floaties look that occurs with some underwater photos?