From my extensive experience, usually the 'scene hog' photog is not really aware of what he/she is doing. They are usually inexperienced photogs and very excited, and just rush in not even thinking about anyone else (once the excitement hits, basic human self-centeredness just kicks in). Most of the experienced photogs and videographers with whom I dive are going to make special arrangements to do their work so as to have the 'scene' to themselves and specifically NOT to affect someone else's dive, or else they are extremely solicitous of the other divers (to the point of giving up shots they may have otherwise had). I lean away from confronting someone directly, because that is the provence of the DM/dive op, and I would let it be known asap that I expect something to be done about it/mentioned, whatever. Passive-aggressive joking sometimes works, but most of the time the person is in denial, so you can't count on that. The 'intervention' dynamic works pretty well when on a liveaboard or similar activity where you expect to spend the next X days together. In any case, good humor and a non-aggressive attitude always will bring you further. However, and again, I would leave it to the OP first to take care of your group, after a gentle reminder (if necessary) that 5 x X dollars is 5 times more than 1 x X dollars. The divemaster/instructor is usually going to try to stay clear of confrontation on the boat, so its unlikely anything will be done/said until a return to the dock, but making your concerns/frustrations etc. known is always cool in this situation. Peace!
CN