C'mon guys. A little common sense here would tell you the face scanner won't work in the dark very well. It's only using the front camera without a decent light source and you don't get good selfies in the dark do you? If you're needing to unlock your phone in the dark often which I'm sure is almost everyone it would be much wiser to switch to the Iris Scanner which works perfectly in complete darkness because the Infra Red light is firing at your eyes to light them up without you even realising it. Not only that, Iris Scanner is far more secure than the facial scanner