I am having the same issue. I have had my 32GB iPhone 4S since it came out and everything has been working fine. Until yesterday when I needed to take a picture, and the shutter would not open.
I have tried Rebooting, Respringing, Reset Settings, tried all various different camera apps that I have and none of them work. However everyonce in a while I can get the Front facing camera to work. But the Rear one will not.
Either the shutter stays closed, or it will sometimes open, but the screen is black, and then it will close and open and close and open in a continual cycle until it finally just closes the app.
I have searched many different posts about this issue, and can not seem to find a solution that has worked as of yet.
Before I go to my very last resort of wiping the phone completely (which I have read doesnt work either) but if I have to retrun it to the store I will have to do this anyways.. I am hoping that someone out there, has a solution that will fix this that I have not tried.... Any suggestions would be appriciated!! Frustrated beyond belief!!!!