There could be a few causes to this issue:
the firmware you just used to upgrade the firmware was corrupted
the firmware or the version installed is bugged.
an application prevents you from using the Camera function normally
For the 1 and 2, you will have to either take the phone back to Support Service at Samsung or use Kies and re-flash the firmware on the phone (back up the data first!) and for the part 3, I recommend uninstalling other camera applications and leave only the default one. Secondly, go to Settings > Applications Manager > All tab > Camera. Tap on the app and then tap on Clear Cache, Clear Data, and Force Stop. Reboot the phone and try taking a picture with the camera while using its features.