Winter is a great time to shoot photos of major cities. It starts to get dark by 5pm and most lights are still on in the buildings. I shot a bunch of photos from a rooftop just south of the Loop and here is one of them A few questions: Is it best to wait for a cloudless night or is there a way to get good results despite the clouds? Is is best to do long exposures at low ISOs or is there a better method? (I shot this with the camera on timer and propped on a pebble) What caused the white spot? I shot almost a dozen shots and this was the only one with a spot. Time for a crazy Chicago story: I live in Chicago. My wife and I were downtown and on a whim we went on the touristy Chicago Ghost Tour. It's on a black school bus. We went to the site of the Eastland disaster http://tinyurl.com/6cmgx3 . We also drove by the morgue used to store the bodies (Harpo Studios present day), the Hull House (site of the inspiration behind the story of Rosemary's baby), the starting point for the Great Chicago Fire and the site of the St. Valentine's Day Massacre. Whenever we got off the bus the tour guide told everybody to take as many photos as possible of everything we see. He asked us to examine our photos. The guide said the gray spots are ghosts of the people from the various disasters. The above photo is the only time since then that I've ever taken a photo that had a spot on it. Sorry for the long story, but I thought this photo could answer two of my questions at once!