Add light to your work area.
Your Mac's camera is adjusted automatically by the application(s) you use with the camera if you are working in an area with enough light.
If your problem continues, use Apple's How to Troubleshoot iSight article. Over time, 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.
If your camera works properly but conditions do not allow you to add light to the subject, iGlasses for Mac can give you manual control of some of your camera's parameters with many common applications.
Message was edited by: EZ Jim
Mac OSX 10.8.4