I have the 5100 and recently the camera started producing dark pictures even when using the flash. It appears the flash isn't on in the pictures, they turn out very dark. Has anyone else experienced this. I'm an amateur by all means and have had a professional look at my camera and they tell me it's just the quality of the camera. However previously the camera took pictures just fine. So I find that a little hard to believe. Any advice? Thanks in advance.