I appreciate the advice very much Scuba Noob. And also Doubler thank you for your factual reply. I am sorry if we got off on the wrong foot ....(or fin).
My wife (who does not dive) enjoyed the pictures of sea turtles, rays, and many other things I took while diving in jamaica. I was using a disposable camera which is pretty bad. So even with the A1100 IS , the internal flash will go about 2 or 3 feet, but the strobe will go much further ...up to about how far on average? I am sure water quality, etc will have something to do with it. 5 to 10 feet perhaps? It is interesting to see some of the cameras sea "____ " brand , sold with a flash, for about 300-400 dollars, ...it makes you wonder if they are just a very poor quality camera that happens to be waterproof.!
Seems like the minimum as you have mentioned is about 500-600 to be able to take well lit pictures. I picked up the A1100 IS last year in a pawn shop for 50 dollars, and it's a pretty decent camera, although it's almost too small. I guess the case will fix that.
I will certainly pay attention to the fact that I could be distracted from diving and possibly damage a reef with my body or equipment. That's a good point. I took many photos standing or kneeling on a sandy bottom, or hovering upside down over some reefs. I am indeed respectful of the reefs I dive on.
I'm starting this sport late in life and am not sure how much or how long I will be able to dive ..but I'd like to start taking some photos asap. Heading to Aruba soon. Thanks again.