Turning off camera during FaceTime

Hello,

Has anyone found how to disable the video while using FaceTime.

I use it all the time at my office, but there's no need to see myself all the time.

Plus, my coworkers, look at me, like if I believe I´m a Kardashian.

So I hope someone can help.

Already tried in preferences unchecking Allow to take photos during a FaceTime Call, but it doesn´t work.

Thanks,

Cristian M.