My Nikon D3300 was working perfectly then today I started using it and it will only produce black photos on any mode. Yes, the lens cap is off. I've tried restoring the settings, restarting, removing and reinserting SD, doing a power interrupt start up and nothing works. The photos come up as black on my display, on the live view setting and on my laptop once downloaded. From what I can see the shutter is functioning normally and the mirror is not broken so I really have no idea what could suddenly be causing this. I'm in Marrakech and losing out on some great moments so any suggestions would be much appreciated.
The same thing happened to me today during a meeting at a short circuit raceway (as you could imagine, there's a lot of dust being flung about). I switched over to my backup, a rather elderly D40, and carried on but when I got home, I ran through a number of things that could have been at fault. First of all I checked to see that the shutter was working normally, which it was. I then went into the menu and selected the "Clean Image Sensor" option. On the first attempt, I noticed that I was getting something, so I ran it again and all now appears to be working again.
I still intend to keep the D40 around as it's a nice camera but this appears to have sorted my D3100 for now.
I just stumbled on this thread as I was just having the same issue. The only thing that changed from when the last time I took ay pictures was I had added a quick shoe to the camera base so I could attach it to my Vanguard tripod. On a hunch I removed it and now my camera is working fine again. WEIRD!