I just bought a Sony Z1 Compact with Android 4.4. It has a special camera button on the side. When the phone is off, you can press this button for a longer time, and the camera apps opens directly, even when you have a PIN lock. The lock is not disabled, only for this app. So after making a picture, when you try to open the image, you first have to enter the PIN.
I would like to encrypt the phone, but I'm afraid that this will disable this function. Does anybody knows how this works?
Update: I encrypted the phone plus external SD card, and the camera button still works.