Flash problem

[subiluv]

A smartphone camera’s flash seems almost deceptively simple: it needs to illuminate a scene while a picture’s being taken. With a xenon flash, timing can be a little tricky, but the LEDs so common on phones make the process a snap. As a result, we can begin to take a properly working flash a little bit for granted; it’s only when problems arise that we really take notice. Unfortunately for new owners of the Sony Xperia Z1, things have taken such an unwanted turn, and it seems that a design flaw may be interfering with the phone’s flash.

[_alexdon_]

Do you have a back case?

[mlb71]

If you have a case, remove it and see if the problem still exists

[Uliwooly]

Aside from a case it could be a protective film that its too close to the LED and/or lense, also it could be that you place your fingers too close to the camera lens and/or flash, it could be that the lens its dirty, etc.