The QML Camera does not focus on Android when camera.searchAndLock is called.
Here is a QtQuick example to test the issue. It starts the camera which will focus on a single click and will capture an image on a double click.
It captures images as usual but on Qt 5.4.0 beta it does not focus. It used to focus on Qt 5.3.1, though:
EDIT 01/07/2015: The bug was not introduced by Qt-5.4.0 but already with Qt-5.3.2. Currently, the latest Qt version with a working QML camera module is Qt-5.3.1.