Share your experience!
It seems that you have posted on different threads regarding camera
http://talk.sonymobile.com/t5/Xperia-M5/Camera-focussing-problem-in-marshmallow/td-p/1174101
http://talk.sonymobile.com/t5/Xperia-XZ/Camera-extremely-grainy/m-p/1189479#M3911
one of them it's on the Xperia XZ, for some reason, either or, do elaborate on the issue.
This is a user based forum, if you think there's something wrong with your device you can troubleshout it, it'll be wise contact your Local support
If you have access to other M5 you could test it to replicate the issue.