Hi CSers, my friend and I were walking about bugis and chanced upon this stairway and i decided to take a photo, and when i showed the photo to my friend, he pointed at the black thing and asked what's that. I looked at the stairs and again at the camera, the black thing was'nt there! we quickly ran out of the staircase LOL anyway anyone can help me identify what is that? It cant be a problem with my camera cause i still could take nice shots after that. help will be appreciated! taken with 450D and 18-200