There's a Sigma macro/converter compatibility chart, try googling.... I just saw it the other day (when I assumed your lens was the Nikkor Micro). --- Luis -------------------------------------------------------------- Ken, >>>Is your lens a "real macro" or an "erzatz" closer focussing so-called macro lens... ie will it provide you with (at least a 1:2 magnification)??<<< I assume my lens is a real Macro, it's the Sigma 105 f/2.8 AF-EX Macro. It will go from infinity to 1:1 without any accessory. Take care, Gregory david Stempel FIREFRAMEi m a g i n g