Apple introduced iSight at the 2003 Worldwide Developers
Conference, intended to be used with iChat AV, Apple’s
video-conferencing client. iMovie (version 4 and later) could also
be used to capture video from the device. In April 2005, Apple
released a firmware update for the iSight to improve audio
performance. As of December 16, 2006, the external iSight was no
longer for sale in the Apple online store or in retail locations.
Meanwhile, Apple began using the term to refer to the camera built
into Apple’s iMac, MacBook, MacBook Air, and MacBook Pro
computers, and Cinema Display. In November 2010, Apple began
calling them “FaceTime cameras”. However, the term was not
retired, as the third-generation iPad, the fifth-generation iPod
Touch, the iPhone 5S, the iPhone 5C, iPhone 5, the iPhone 4S, and
the iPhone 4 all incorporate an “iSight” rear camera in addition
to a front-facing “FaceTime” or “FaceTime HD” camera.
So “iSight” used to be Apple’s name for front-facing video chat cameras. Then they started calling the front-facing cameras “FaceTime”. Then they brought back the “iSight” name for rear-facing cameras.