I have the T1i and it came with the factory lens and a 50mm lens when I bought it and here are pictures with the 50mm and the 100mm I purchased about a week later
50mm

100mm

in my opinion the 50mm is not much better than the factory 18-55mm lens so I really can't suggest it over the factory lens for coin pictures. You will need a tripod or something to get quite a distance away on a large coin like a Morgan with the 100mm lens because it will not fit in the view finder if you don't. I didn't take any pictures with the factory lens when I took these two but I am guessing you probably would not have been able to tell the difference between the factory and the 50mm lens by the pictures
50mm

100mm

in my opinion the 50mm is not much better than the factory 18-55mm lens so I really can't suggest it over the factory lens for coin pictures. You will need a tripod or something to get quite a distance away on a large coin like a Morgan with the 100mm lens because it will not fit in the view finder if you don't. I didn't take any pictures with the factory lens when I took these two but I am guessing you probably would not have been able to tell the difference between the factory and the 50mm lens by the pictures





















