I'm about to order a macro lens -- I had decided to get the sigma 150 2.8 but after reading and viewing this site I'm wondering if I should not just get the nikon 300 f/4. I'm new to this and I'm concerned that the 300 is not a macro lens but it seems to do great with macro shots. Do you need a true macro? Please excuse my lack of knowledge but the 300 f/4 is a lot of money. I also want to do some birding shots and I already have a 1.4x TC. Can I "excuse the pun" kill 2 birds with one lens? Thanks for helping out a newbe.