Hello. I have read your post and understand the issue that you are experiencing with your stock camera. You may want to try and power the phone off and remove the battery then try to reuse the stock camera. If that does not resolve the issue, you can always try doing a hard reset on your device.
Does anyone else have the issure where the stock camera will not focus on something when you press the button down? Any other camera program or barcode reader it will focus except for the stock camera.
my pictures were coming out a little blurry on my camera until i went to camera>menu (the fours squared button the the right side of your phone with one whited out)>settings>checked face detection (make sure the check mark is green)