Here are my suggestions for your camera problem.
One of them will resolve your trouble. Try them in
any order you like.
• If you have not already done so, restart Mac and
try again. A simple restart often clears up minor
issues, including this one.
• If Apple's http://support.apple.com/kb/HT2090
suggestions do not help you, (the "reset" suggested there
often restores normal function,) continue with the following.
(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.)
• Use your Mac's Disk Utility to repair permissions and then
download and apply the latest Combo Update, for your Mac OS,
the current one is at: http://support.apple.com/kb/DL1581
(yes, use this Combo even though you are already running 10.8.2)
• Repair permissions again immediately following the system restart
that completes the Combo update.
• 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.