The waterproof Xperia Z3 comes with a great 20.7MP main camera. If for any reason you want to change the camera quality as well as the aspect ratio on your Sony Xperia Z3, do as follows:
1. Open the Camera application
2. Go to the Shot Modes and make sure you have selected the Manual mode
3. Now go back to the camera, and tap the 3dot icon on the top left to open the Camera Settings.
4. Tap the Resolution and change the quality of pictures (both size and ratio) taken by the camera