I shot this band before, they are one of my favorites. Progressive Opera Metal.
And that's what it is. Female fronted with singer Dianne van Giersbergen, with classical soprano voice. And a brilliant guitarist. Awesome group.
Released their first album a couple of years ago already, but are working on the second album that hopefully will be released soon. You can check them out on their own website: Ex Libris.
Unfortunately there was hardly any light on the stage...