Here's a crop of a photo of Comet Lulin shot with the Nikkor 200mm f/4 AI telephoto lens. I had the IDAS light pollution filter on the lens to help bring down the sky fog. There's still a bit of vignetting even though it's cropped. You can clearly see the dust tail (anti-tail) to the left of the comet. The proper tail is not that distinguished as it is projecting away from us. The bloated stars and Saturn were caused by me not using a smaller aperture.