In addition to buoyancy issues in U/W photography, one thing you should become aware of is that U/W photographers are *notoriously* bad buddies. Most of us are well aware of that fact and make sure we make our buddies well aware of it. Even those of us who have good buoyancy and are polite (i.e. don't elbow other divers out of the way to get a shot of a cool critter) generally make terrible buddies.
We either a) spend Gawdawful lengths of time at one anemone trying to get "just the right" photo of it and bore our non-photographer buddies to death while waiting for us to finish shooting; b) focus our entire attention through our camera lenses so that we wouldn't notice a whaleshark swimming up next to us unless it whacked us with a fin (think I'm kidding? I haven't missed a whale shark, but I *have* missed a shark...
; or c) stop dead to shoot a picture and totally miss the fact that our buddy, who we neglected to inform that we were stopping, has lost us.
U/W photography is also a GREAT way to lose any disposable income you had left after you started diving - you may *think* you have a nice camera now, but in a couple of years, you'll be upgrading, getting multiple strobes, lenses, ports, etc. U/W photography is the crack of diving.
Don't start trying to take photos U/W until you're *really* comfortable diving - it's serious task loading and more than one U/W photographer has run low or out of air forgetting to look as his/her gauges while trying to "get the shot." Personally, I try to make it a habit that after *every* shot, I check my gauges, and look for my buddy. I also make sure I warn my buddy prior to getting in the water with them that if I have my camera, I *will* suck as a buddy and that they'll need to keep an eye on me so as not to lose me. For the most part, I haven't had any problem with that, as that means they get to see cool stuff, since I'm spotting cool little critters and pointing them out to my buddy
. (Well, people do keep coming back to buddy with me again, so I guess that's a good sign
).
Have a great time getting used to diving and then getting your rig set up. Enjoy!