Who has experience using this Tamron lens on a crop sensor EOS? A good friend only has this combo and wants to do strong closeups (near ~1:1) on a very limited budget. I wasn't sure if I should recommend extension tubes or macro-diopters for this lens. I was quietly thinking: May be get an old (even-MF) macro lens instead... Before you ask: No, he hasn't got any prime lenses. He lives 700 miles from the nearest camera shop in the Australian Outback. May be I just mail him an old +2 diopter I have.