A truly amazing solution to most of the problems with focus is Joby Gorillamobile mini-tripod for the iPhone. Set it at just the right height (have the text fill as much of the screen as possible), make sure the iPhone is perfectly parallel to the desk and you essentially get the very best photos you can take with your iPhone. No more shaking/blurriness and the text is as large as can be (which is key to OCR). You can now touch the screen to help the iPhone focus without fear of making the camera shake. It takes a minute to twist the legs of the tripod to get it to be at just the right height but guarantees a steady hand.