Hi everyone, I'm in the market for a 50mm f1.4 lens for my D100. I don't know much about these lenses since I'm new at photography, but what is the difference between Nikkor 50mm f1.4 AF lens and other "D", "Al", and "AlS" nikkor 50mm. All these are manual focus but would they still work on the D100?. I need something that would work well for portraits and wedding photography. I'm not anywhere near a professional but I plan to practice my friend's wedding. Thanks a bunch for all the help.