All of my lenses are canon glass, but I want to experiment with macro. 100 mm with 50mm ext tubes to get 1:1 go for about 150 and up on Ebay. Promaster sells a 100 mm macro lens for about 100 bucks. I know you get what you pay for, but I'm not sure how long I will hold a interest in macro. I could get the PM and experiment, but if it's junk, I'd just probably wished I'd gotten the canon in the first place. Any feedback about these lenses would be greatly appreciated. Thanks, J.