Hi nemo
Totally agree that diving skill should predate photo skills.
Another thing that all should note is that underwater photography can be very engrossing, in fact, too engrossing.
Just to share, personally I was in a situation where i was so engrossed in taking photos that I was nearly out of air. Although I was not very deep (about 12- 15m), I spended so much time taking shots that my computer went into decom. Although I was constantly checking my air and my depth, did not occur to me at that point in time that I could actually go into decom.
(lame excuse for not looking at the computer). Prior to discovering that i was in decom, I though that i had the situation under control as i knew how much air i needed to end the dive but the decom stop threw my calculations off.
When i did discover it, went up to 5m for the decom stop, the computer required me to do a 5min decom stop there. Shared air with another diver for about 2-3 mins and ended the episode (lucky without incident)
It was really a lesson for me. And for all others, trust me, this is not the best way to learn and is totally not acceptable as it puts your buddy in potential danger too. As with every dive, expect the unexpected and take all possible precautions for the unexpected.
By the way, my eariler mail on task loading was actually refering to trying to shoot in manual mode for my cam for the first time and since my flash does not have TTL, it also has to be control manually, was thus very difficult to make all the calculations in "realtime" esp on moving subjects.