We are sorry for the inconvenience. We have found the problem in the remote camera and will will submit a bug fix today.
Focus and exposure function will be fixed on iOS7.
The maximum resolution the remote camera can capture is FullHD (1920×1080), right now there is no way to have liveview and more resolution. But the burst capturing of the iPhone 5s might be good enough to provide a higher resolution capturing and liveview.