Great article.. I'll keep this short for now, my cat is laying on my right arm so I'm typing with one finger! (she just moved... whew) First off for Dysfunction:
Katz Eye Plus - KatzEye Optics
Great people and great products. They'll install one for you if you don't want to do it yourself. Well worth it.
When I was in Hungary, I had to bring my Sigma 28 1.8 lens in for repair because the focus ring was not turning smoothly, due to it having fallen while attached to my D300 while on a tripod. Was in a cemetary, and some kid ran bye, knocking it over... the whole rig fell on top of a marble stone! The camera's casing split open a bit, revealing the the alloy inside of it, and I was mortified! Amazingly though, everything still worked exactly the same. That D300 is a beast.
To the point, when I brought the Sigma in to this small shop, they not only fixed the focus ring, but used the kind of software talked about in the article, and calibrated the lens as well. It came back to me in better shape then when I had first bought it, focus was amazingly smooth and images were sharper than ever! The best part? I think I paid about $20 USD for this !
They also have an official Nikon factory over there, and it cost me $60 to fix the casing, as well as have the sensor cleaned and calibrated! It probably would have cost me several hundred for the same service here in the States. Man I miss that place...
Doug