Because your problem persists after you restart Mac, try all relevant suggestions from http://support.apple.com/kb/HT2090.
Be sure to test more than one camera-enabled
Apple app.
(BTW--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 Mac's built-in camera, the same info and troubleshooting applies.)
Also, only one OSX app may use the camera at a time. Check > Systerm Preferences...
> Users/Accounts for login starup items that might be using your camera.
Message was edited by: EZ Jim
Mac OSX 10.8.2