The Tamron 90mm macro at B&H and probably many other places is selling for $449 and there is a mail in rebate that ends April 30 giving it a total cost of $399. I've applied for Tamron rebates on two separate lenses and Tamron has been very prompt. The ones for Nikon are designated BIM which means built in motor for those times you want to use auto focus if you have a camera body without a focusing motor. The warranty on Tamron lenses is six years and I register mine via the net. It is not internal focusing but it is a good sharp lens.