Memory card speed can affect how long it takes for a shot (if that was an issue) - some other people on this forum have taken speed hits with certain brands or classes of cards. As for focus, it seems just fine for me, takes about 2-3 seconds in low light though, so if that's unacceptable then I don't know what to tell you. Sometimes my dSLR can take awhile to auto focus (I have noticed, however, that the phone is fairly consistent with searching for 2-3 seconds every time in low light - seems quicker in the daylight).