This is a topic I've been intending asking about.
Jack-r, what's a little "not" between friends, especially for something as ephemeral as bubbles :-)
My CP5000 ike housing is just very slightly negative when it's empty. Add a camera and it sinks fairly well, add the DS125 strobe and arms and the whole shebang is significantly negative. I would guess I could take 2-3 lbs off my belt to compensate, but my preference has been to keep the weight on and add more BC air as I'm usually a little light by the end of a dive anyway.
Last trip (first with camera) I was in "touch absolutely nothing" mode. One of the dive guides watched me trying to hang upside down to take a close up w/o touching anything. More clown than clownfish. He gave me some advice on the boat and next dive. His recommendation, "having taken thousands of UW pictures" --endquote-- was to dump most of the air from my BC, going very negative and allowing me to literally lay on the bottom, and to brace my elbows against rocks, sand, whatever.
I must admit I wasn't really comfortable with that, and for the rest of the trip I tried various compromises, mostly involving staying neutral but finding something non-sensitive to hang onto with one hand to take the shot, or going slightly negative and kneeling or fin pirouetting on sand or gravel.
I can definately see major concerns with coral - I've been told that in some places (red sea) dive operators can get busted if they allow clients to touch the reef. I certainly applaud that, and feel equally strongly about bashing into anenomies, gorgonians, and anything else "substantial."
But what about laying down on sand or gravel? So long as there are no nests or holes etc is that OK? What about rocks? Bare or barnacled? How about weed/algae covered? The LaPaz wecks (lapas03 and fan-min) have only been there a few years and are covered with 1-2 inches of assorted growth already. Certainly if I'm out in the woods I'm not shy about tramping through the grass, or even doing a little gardening to get foreground stalks out of the way to get a decent shot of a mushroom, so given the rate that stuff has built up on fan-min would it be OK to (gently) rest on a weed-covered rock?
Before I started carrying the camera, it all seemed very simple as there was no need to touch anything. Now it seems more complex, with touching stuff becomeing a huge boon at times, and as I'm not sure which substrates are "damageable" and which are "robust" I'm not sure what is acceptable.
As I see it at the moment, so long as there are no holes, nests, etc it seems OK to kneel or lie on sand or gravel if necessary. Likewise it seems OK to perch on rocks, pilings, etc if they are bare or covered with well-stuck-on shellfish (limpets, barnacles, etc) or non-frondose weed and algae--this stuff gets grazed by fish constantly and occupies that niche through fast growth and damage resistance? It also seems that finger-pivoting or pinching on to "dead areas" (or even onto live areas that you can be confident are built to stand it, large mussels for example) does no real damage. Any contact should be carefully considered and minimized, but some of this seems OK (and in many ways seems less damaging than some dive operator's practices of anchoring on reefs and wrecks and grabbing hold of any interesting critter to show the clients).
I hope this doesn't start any major fights and flame wars, as I'm sure people will have different comfort levels and rationalizations, but where does everyone else stand on this?