[richardpcrowe]

The 90mm Tamron f/2.8 AF SP macro lens is the model that was issued prior to the present generation lens that is identified with Di added to the Tamron designation. The Di lens is "supposed" to be optimized for digital sensors but, I can't really see how much better the Di lens could be over my present non-Di model. My Tamron gives me imagery that equals or is superior to my "L" lenses.

If you have patience and a bit of luck; by haunting the used equipment sites such as eBay, Fred Miranda and Photocamel - you "may" be lucky enough to find one of these lenses for between $125 and $150. I got my copy for less than $125 including shipping and that is about the price of a top-line set of extension tubes.