Problem with iPhone 6 camera

I couldn't find any information about that problem,

First of all, it's not always like that, sometime it's working fine.

I taught that it is a problem with the iOS because it's affecting both cameras, but a settings reset didn't helped, should I try a full reset of the device?

I just found out today that when I apply some pressure on the back of the device the pattern change, so I'm not sure that it is a software problem.

Is this a common problem that occurred in earlier version? Does this have a name so I can look for more information?

If it helps, I think that when it occurs, it's in both cameras at the same time.

Thank you for your help