I currently have a Nikon D50 with a 18-55, 3.5-5.6 lens and 55-200, 4.5-5.6 lens. I want to get a faster lens, but don't know which one to get. Most of the photography that I do is portrait, event photography and I am doing my first wedding this weekend. I do a lot more photojournalism type photography than posed shots. Any suggestions for a lens that would benefit me? And, if it makes a difference in quality if I use a non-digital lens on my digital camera? Thank you for your suggestions!