Vivitar 100mm f3.5 macro

This lens is very difficult to review. There is a very big difference between the optics and buildings. Of course its a cheap lens, but as a "real macro-freak" normally I am used to better lenses. I have 6 top-macros from Sigma, Tamron and Canon and...

I bought this lens used on eBay when I was looking for a cheap macro lens and I have been very happy with it. It has great image quality, the pictures come out sharp and with very good contrast.

What is the focal length with the 1:1 adapter?

(added April 2006--this lens may no longer be available as a Vivitar, I am not sure, but the exact same lens is still available under the Phoenix brand name. It has in the past also been marketed by Pentax under their brand name for K-AF mount...