The Combo update worked great on my (older) 13" MBP. One of the following suggestions will fix your problem.
(1) If you have not already done so, restart Mac. Then use your Mac's Disk Utility to repair permissions and try the camera again.
(2) If the problem is still there, try all relevant suggestions from Apple's http://support.apple.com/kb/HT2090. (The "reset" suggested there often restores normal function.)
(Apple has changed the built-in camera's name on newer Macs from "iSight" to "FaceTime" and then to "FaceTime HD." Regardless of the name of your built-in camera, the same info and troubleshooting applies.)
(3) If the problem persists after using Apple's suggestions, download and apply a fresh copy of the latest Combo Update for your Mac OS: http://support.apple.com/kb/DL1581 (yes, even though you are already running 10.8.2)
Repair permissions again immediately following the system restart that completes the Combo update.
(4) Properly applying the Combo version of updates can sometimes correct software problems, but, if your trouble is caused by a hardware problem, there are no user serviceable parts of iSight. For hardware help, contact an Apple-Authorized Service Provider for service.