Some of my friends actually went ahead and took solo diving course, carry alternative airsource etc for exactly that reason. Photographers are very poor buddies and put 2 together are not always practical as they can lose each other just as quickly.
When I dive with a group of non photographers with diveguide, depending on visibility, I do try to at least keep track of the direction that they go and if visibility is not good, I end up not spending as much time as I would have like on some subjects that I find so that I still can kind of keep up with other people.
Sometimes I do stay longer if I happen to have a diveguide and DM assistance with the group as at least one of them tend to hang back a bit so I know where to follow. Of course this is with the understanding that the rest of the group don't mind. Luckily most people that I dive with do take their times looking at all the little critters and tend to dive at slow pace anyway.
It really depend on your buddy or the group you dive with. It is easier if you dive with the same person or same group regularly as you tend to know more about them and they know your habit so all the detail can be hammered out and nobody gets upset.
One time I dove with someone new, who just recently got certified and of course a whale shark came by. She got pretty upset afterward because I lost her in a mad rush to follow the whale sharks and the DM did exactly the same thing. Visibility was very good and they were lots of other divers in water. Took us awhile to regroup afterward.
If I dive with someone new, go to new places, new DM etc, I try to talk to them before the dive, let them know and ask if they mind if I hang back sometimes, etc. Generally when they see the camera, they kind of know what's coming anyhow
For me, night diving is actually quite fun as a photographers. I find most people don't swim nearly as far at night and it is relatively easy to spot other divers. I do keep myself well lit with a little signal light on my tank, on my bc front and most people pretty much know where I am most of the time because of the strobe.
I guess I did not talk much about precaution I take when diving wiht camera but chippy already pretty much stated a lot of the essential things, now its just a matter of not getting other people upset with my style of diving