Our Bright are they
Here are a few of the specs that might answer your question... I hope this helps!
Twilight factor: 12.7
Prism system: Roof prism with phase correcting coating P40 and HighLux-System HLS
I regret that I can't find a way to compare their brightness for you. The Leica website says they are "brighter, sharper, more compact, more functional and robust than previous binoculars of this lens size."