Can't take pictures with my iPhone 6s, all I get is a black screen that's all?

Can't take pictures with my iPhone 6s, all I get is a black screen that's all?

Your camera might off disconnected from your phone. I would suggest backing up your phone in icloud and then restarting it completely and then log in to your icloud and click the set up as (your phone's name) option.

Did you try refreshing the app. If that doesn't work I just restart the whole phone which usually does it.