We just returned from DC. It was absolutely the best!Anyway, my DDs and DH did the dolphin swim and I did not. They went off to do their video and training while I waited on the beach for them to come out. When they came out, I got great pictures of them. Depending on what section you are in - there are 3, you can get some great pics. The life guards let me stand on some rocks right where they were having their dolphin experience and I got upclose, great pics. when you are waiting for them to come out, talk to the lifeguards that are there by the beach. they gave me great tips and told me what I could do.
We bought the pics they took too, but I got great shots of my own. You shouldn't have a problem. Have fun! Our DC day was the best day of our trip. Just a great, relaxing, fun experience and we would do it again in a heartbeat.