From Samsung Website:
Video Chats without Buffering
Stay constantly connected with friends and family from practically anywhere, thanks to the front facing camera with QIK, the popular video chat app from Skype specifically for Android OS based devices. And theres no need for any buffering with T-Mobiles all new 4G network, perfect for video chats. The Galaxy S 4Gs 5.0 Megapixel rear facing camera shoots sharp photos and HD videos with excellent resolution.
Looks like the rear cam is for stills only.
It does mention the rear cam will take HD vids....I’ll keep looking.
I have the same phone. I use the camera for video all the time. I mean the camera on the plasic side, not the gorilla glass side. Never used the one behind the glass.