DSC_0699 by fiftyonepointsix, on Flickr
Nikon Df with the 85mm F1.8, manual focus, wide-open. ISO 12,800 and 1/320th second.
M Monochrom, Canon 100mm F2, wide-open, ISO 10,000 and 1/125th second.
I have an easier time focusing the Leica over the Df, but both are very good in low-light...