That is a serious bummer. Sand Bar sharks are hard to find down there most of the time, and hard to get close to even if you do find one.
Not sure if it's an option for you, but since I switched to diving a CCR, I have found that when something like that happens, I can usually just hang around and wait for all the OC divers to head back for the boat. I camp out and the sharks come back. Then I get my photo. I might be the last one back on the boat by 5 minutes. Maybe 10. But, I haven't had a reason to do that very often and I haven't gotten yelled at yet.
I also think it's perfectly reasonable to bring it up during the dive briefing before a dive like that.
DM: "Okay, anyone I have any questions?"
Me: "I don't have a question. I just want to say that I will be trying to take pictures down there. I will do my best to stay out of everyone else's way and I would appreciate the same courtesy in return. If you do happen to swim right into the middle of a shot I've been working to get, we're going to find out how long it takes these trauma shears to cut through a low pressure hose."