On auto mode on my Nikon D5100 my flash appears to be disabled. It works in manual but not auto, where if I look at the settings ('i') flash is showing as off. As far as I was aware I couldn't disable flash in auto so I'm v. Confused and frustrated. It's now operating like the flash off auto mode. Can anyone help? Pleeaase? I'm in Madagascar and missing out on lots of amazing photo opportunities!! Thanks in advance!