A big problem is that there is no autofocus in the stock camera app
I've found procam to give the most control, but I really have found that I can get the shot that I want with the stock app, still that's the one that I recommend if you want more control.
Tap to focus, tap and hold to lock auto focus and auto exposure.
taken with iPod Touch 5, not iPhone.
See - then why do a LOT of my pictures ALWAYS come out blurry unless I tap and hold??? It even happens to other people. For example, yesterday I bumped into a celebrity I really liked and I told a friend to the picture. Both were blurry! The HDR one wasn't as blurry but both were definitely not crisp. And it's not that my camera hole is dirty either.. :/