Originally posted by EDstrg87
I have a problem:in the last 3 months seems like it's not able to focus to infinity in AF and in MF;in a range of 10 meters it focus fast and accurate..What do you think could be?

Not sur eif this helps.
I had similar problem with Sigma 70-200 HSM. Originally purchased as a demo unit from CR Kennedy, The Australian distributor. It would focus well at short distances but anything over 20-30 metres. It took a bit of convincing the repair people of the problem but once they accepted it they took it apart and determined a faulty circuit board. In the end they replaced the lens as a new board would take weeks to obtain.