I have a Sigma 100-300 f/4 that I love - very sharp and the ideal range and aperture. (As we all know Canon does not offer a lens like this). However, a couple months ago the autofocus stopped working. I contacted CRIS Camera, which is one of Sigma's authorized service centers (and is in my state) and they said because the lens is no longer made they cannot repair it. They were not even willing to look at it. I think (my memory is faulty here) I emailed Sigma afterwards and they did not reply. Just wondering if anyone knows of a reliable camera repair that would likely be able to fix it?