When the camera's completely switched off, hit the powerbutton and you'll go straight into camera mode which lets you shoot immediately, then about half a minute later the interface seamlessly goes back to smart mode, which is when you can hit the back or home button to toggle the Android unlock screen (though we'd rather go straight into the home screen).
The camera itself looks very similar to the P310 -- there's a nifty mode dial up top, along with a zoom toggle, control dial, powerbutton, stereo mics and a pop-up flash.