I just got my Nikon D60 and very new to dSLR photography. I'm testing and shooting at every possible opportunity and I'd like to post an image of the Fullerton Hotel taken at ISO1600. There's a circular smudge at the left corner of the photo and I don't know if it's a lens defect or user defect.
Btw, the graininess / smudge disappears at lower ISO speed (ISO800). Any advice will be greatly appreciated. Many thanks!