About the front camera and zoom. The Camera API support front facing camera zoom and smooth zoom, it's the stock Sony Camera app that doesn't support it or has no zoom implemented for the front facing camera, not sure exactly why but if I use the Google Camera I can zoom without any problem at all.. just not sure why would I zoom to take selfie...
Anywho, try to open this link from your mobile phone: https://play.google.com/store/apps/details?id=com.google.android.GoogleCamera - install the Google camera, and try to zoom. To zoom you cannot use the volume control, you have to gesture zoom with your fingers over the touch screen.
