One wouldn't think it was that dark, after a 5'20" exposure, the lights on the right look like some veritable flood lights to me, but hey, cool! Very smooth water you got like this, and how did you measure your focus when you could hardly see a thing?
This is one of the amazing aspects of photography, when by long-enough exposure you get the photo to show so much more than met the eye at the time!
I never said I could hardly see a thing. It was dark enough but still had small amount of light. I actually had the focus on the roof top that's a bit off-center, the aperture was at f/14 so it was enough to produce sharpness across the frame.