I just got back from a mid-semester vacation to San Diego and snapped a few photos while I was at it. I went to Coronado at night and, from there, you can get a great view of the downtown skyline across San Diego Bay.
I had my camera on my sturdy Manfrotto 190XPROB with the 496RC2 ball head to be sure there was no vibration. Also, I had the legs on their shortest setting and the center column was not extended more than a few inches. And yet, about half of my photos of the nighttime skyline came out blurry. The first one was sharp, and the next one was very blurry, followed by a handful of almost sharp photos. Each time, the camera reported that it had focused (although I wasn't looking through the viewfinder to see exactly what; I was using a remote cable release). However, NOTHING in the out-of-focus photo IS in focus.
Is there some sort of limitation on focusing with night photography, even if a part of the image is bright (the bright city lights)? And once I finally figure out how to get good focus every time, what can be done about the blown-out highlights in the city lights? HDR?