This is my first time starting thread in photography forum. I am wanting to purchase a macro lens for my Nikon D40. You have to understand I have a really nice camera, but I am an average photographer with a small pocketbook. I am wanting to learn more, and be able to take quality pics. I have looked at threads and reviews on the Tamron 90, and I am leaning toward this lens. I can top out about $400-450 for my purchase, less would be great. I need thoughts on going for the Tamron vs going for maybe a used Nikon 105. Or possibly saving and buying a used Tamron 90. Has anybody bought a used lens, good or bad experience?