10.10 updated and my internal camera not working I have just updated my 2013 MacBook Pro 13 inch with 10.10 Yosemite, but now I can't webcast.  

How do I turn the camera back on?
Hi I had the exact same problem. Played around with terminal and figured out a way to reset the camera. Just open terminal, paste this in to it, and then press Return:

sudo killall VDCAssistant