Is photomatix better than using photoshop CS5 with HDR? Also, my camera will take up to 9 different exposures, does it really matter how many you take, or is 3 the norm?
I think that the number of exposures "required" is often actually going to be a reflection of what different individuals' cameras are capable of. A person that has a camera that will only do a 3-shot bracket will tell you that's plenty good... others will tell you as many as 9 will be good.
In other words, the question of "how many shots should I take?" is more or less equivalent to asking the forum "how many shots does your camera bracket?". Chances are, any given shooter will be most familiar with bracketing as many shots as their camera is capable of bracketing. A person that can bracket 9 shots in their camera will say 9. For someone that can bracket only 3... the answer will be 3.
In the vast majority of situations, a three-shot bracket will do... and if that's all a given camera can do, that'll work just fine. If your camera takes more shots than that in bracket-mode, then feel free to experiment... but I don't think you'll see much improvement by bracketing, say, every 1/3 stop between +/- 2EV. Alot of that will just be redundant data.
My camera takes three shots on bracket, and indeed, I will tell you that three shots almost
always does it. There are occasionally situations that call for a few more shots on the shadow or highlight end to gather all the detail though, in which case I'll run two three-shot brackets for a total of six shots.
It's rare that you'll need more than 3 shots.
It's next to impossible to you'll "need" more than six shots.
But, then again, having more can't necessarily hurt, I suppose.