tl;dr - If the camera app never loads (the aperture/shutter stays closed forever), you may need to replace the whole iPhone. That worked for me. More conservative measures did not help.
I have an iPhone 5, black, 64 GB, AT&T. I got it in September 2012, and the camera app worked properly for about 2 months. Then it stopped working - when I tapped the "Camera" app on the home screen, it would just show the closed aperture (closed shutter) forever. The aperture would never open, even if you waited minutes.
On rare occasions, the aperture would open and it would show total black, no image. Also, the 3 camera buttons would not work (flash, front-vs-back, and options).
Restoring the firmware did not help.
Apple replaced the iPhone for free and now it works fine.
I have an iPhone 5, black, 64 GB, AT&T. I got it in September 2012, and the camera app worked properly for about 2 months. Then it stopped working - when I tapped the "Camera" app on the home screen, it would just show the closed aperture (closed shutter) forever. The aperture would never open, even if you waited minutes.
On rare occasions, the aperture would open and it would show total black, no image. Also, the 3 camera buttons would not work (flash, front-vs-back, and options).
Restoring the firmware did not help.
Apple replaced the iPhone for free and now it works fine.