I have noticed a lot of professinal divers use the Cyklon 5000 or the Oceanic Omega-both side breathers.
But, if you have a reg. with a adequate exhaust T(ScubaPro has small Ts and Oceanic and Atomic(I think it's Atomic) have very small Ts) like an APEKS then it's no problem. I like my Odin for photography since it's a side breather but I do hold my breath when I shoot, so really I don't think side exhaust is a big deal.
There are so many other factors that will ruin your U/W photo e.g. backscatter, subject moving(I have a lot of shots of fish tails), not getting bit by a close Moray, bad O rings, wrong apeture setting, wrong lens, wrong flash intensity......oh the list goes on and on. I have found U/W photography much more challenging than I had ever imagined.
Getting bubbles in your photo is the least of your worries!
If you want to do U/W photography then your troubles are just begining. It's quite the challenge.