It is normal to hear the rattling sound or click sound of certain internal components. The reason for the noise depends on the issue.
Select the issue for more information.
Why is there a rattling sound when I shake my device?
The camera module used for the Xperia® PRO-I wide camera uses a voice coil motor to drive the lens group inside Lens moving part.
When the voice coil motor isn't powered, this Lens moving part may produce a sound when you shake a device or tap on one of the corners because it can't be held at a particular position inside the Camera module.
This is not a malfunction, and this sound doesn't affect the performance or durability of the camera.
Why do I sometimes hear a click inside my phone?
When starting the camera app, the phone makes some sound. Users may also feel small vibrations on the phone.
When any camera app starts (Photo Pro, Cinema Pro, or Video Pro), the wide camera operates initialization which switches the iris between F2 and F4 several times in a very short period of time.
This makes a blinking sound but assures the iris is working correctly.
This is not a malfunction, and this sound doesn't affect the performance or durability of the camera.