On my Windows desktop I am used to being able to lock it immediately using Windows+L when I step away from the desk. I did some Googling this morning and see that the similar shortcut in OS X is Control + Shift + Eject (http://osxdaily.com/2011/01/17/lock-screen-mac/). The problem is, I am on a Retina MacBook Pro and don't have an eject button. Has anyone found an alternative way to do this on a Retina MacBook? Thanks.