Possible Duplicate:
What is a macro lens?
What is the difference between a Nikon “Micro” lens and a “Macro” lens?
I know what macro photography is, but what makes a macro (or in Nikon's dictionary: Micro) lens macro? For example, I am looking at this and this Nikon 105mm lens and they seem to have similar spec, one is f/2.8 and the other is f/2.0, but one is labeled Micro.