My question is a bit difficult to explain but I'll try my best. Do me a favor and take a photo while completely covering the camera lens, then view the photo in the gallery. Make sure youre in a dark room and viewing the photo in full screen, wait a second for the back and task manager buttons to turn off as well.
Is your picture completely black or are the outside edges and corners fuzzy and white almost?
My previous phones are Galaxy S1, 2, 3 and 4 along with the Note 3 (which I miss :/ ) never had a problem like this, I do believe some GS2s had a similar problem with the screen being spotty in black images.