I love the Optimus G Pro and the G2's camera. It has ZERO shutter lag, something which I cannot find in any other camera app so far. I used to use the G Pro for work and loved how fast the camera was. Which is crucial when you are trying to take pictures of your child.
So I was wonder if the camera app in the G2 is deeply intertwined in the OS like the camera on the GS4 is, or if all I would need would be the camera APK file.