was taking photos at the Los Angeles Tofu Festival , rather hot or least 90 degrees. I took 4 shots while in the shade ,put the lens back in my bag with the camera. About fifteen minutes later I took both out of my bag and the lens would not focus. I could hear a whirring as the camera tried to focus the lens. dead huh, I came home to prepare to send the lens back to Sigma , took one more look at the lens and it started to operate again.
I called Sigma and reported what I had read about this lens on Fm and they acted like they had never heard of this.As of now the lens is on its way to NY Sigma for repair or replacement. This particular lens was purchased at ADORAMA . This is my second lens to be shipped back for repairs, I dropped the other one. No fault of theirs