I am an avid underwater photographer, but not a zealot. My air consumption and buoyancy do not suffer when I use a camera (housing, frame, strobes, etc.).
First, I typically do not take my camera on the first dive in a new locale, or if I have a new piece of equipment. Second, I have two short ropes with clamshell clasps on each end that clip high on each shoulder on my BC and to each side of my camera, which is slightly negative, so it hangs just below my chest. I tend alter my settings before I jump in, and tend not to fiddle with the camera until I am at depth, oriented with my Buddy, taken headings, etc. Third, I have my equipment, such as my computer, on the inside of my right wrist to I can always easily see my readings as I hold my camera. Fourth, I will not hesitate to skip a picture if it potentially could injure me, the subject, or the environment- just a reason to come back. And lastly, I will not hesitate to leave my camera clipped off if conditions become too demanding. Recently did this in NC, when the current ended up being much stronger than first thought and there was no where to hide.
With all of this said, I often dive with my daughter or good friend (who had 3,900 dives and is an avid photographer who taught me). Both are photographers, and we are all similar with low air consumption. But I would not allow my daughter to photograph until I felt she had the skills WELL mastered (and taken Stress and Rescue for multitasking) before she could start to carry a camera. Ever then, I set her up with a small housing with a single strobe .
I do often find the most obnoxious photographers to be those who just got a camera and have to push it into every situation, while flailing arms, legs, and others. Part of my training with my daughter has been courtesy. For example, if we find a desirable critter, or the DM does, we slowly move in, get 2 or 3 fairly quick shots, then wave in the next person. Only after everyone has finished, and usually after a short period to let the area settle, we go back and get some more involved sessions, taking time to study environments and behaviors (she is studying Marine Biology in college). Often, on a wall, we have let everyone get their shots (while stirring everything up), then let the group leave, usually with the DM, and we settle in for the rest of the dive on the wall by ourselves. It is always amazing what critters will come out if you wait 10-15 minutes and move slowly and calmly.
I am currently getting ready to teach the Photography Specialty, and part of the reason I want to do it is the emphasize the way it should be done. As in SCUBA, slow and gentle wins the race.
Terry
PS- my avatar- This happened when 4 or 5 divers were pursuing a turtle-a futile effort. I was further up on the wall. The turtle must have found me curious, and I snapped the photo as he gracefully swam right next to me on his way to the surface.