The Sony Xperia Z2 has a dedicated camera button on the side of the phone. It allows to take a photo quickly by holding down this button. This brings up the camera app and pressing the hardware button again takes a picture.
This is a great way to quickly snap a photo, but it has its drawbacks as well. For instance, it may be pressed accidentally, which happened to me multiple times, leaving me with blurry or black photos that I had to later manually remove.
To disable the camera button on your Sony Xperia smartphone, you have to go to the camera app first. First, I was looking for a toggle somewhere in the settings, but that’s not the right place to search. So go to the camera application and open settings (the three dots in the top right corner). Then choose Quick Launch and choose Off.
There is no more to it. Pressing the camera button will no longer automatically launch the default camera application on your Xperia device. One less annoyance ;-)