I find that using touch to focus is difficult when I'm using the phone with one hand. I often have to turn it off. Anyone else have this issue or a solution for that?
It works fine for me. Basically hold it cradled, thumb on bottom (held landscape), last three fingers on top, using my index finger to tap (or, with KitKat, to move the tap to focus target and then tap.)
I rarely use it one handed for photos, though. So perhaps the solution for you is to use both hands?