11-23-2010, 11:18 PM
I've got similar problems. Neither my Tamron 17-50, my Sigma 50-150 nor my Sigma 10-20 won't AF in live view / movie mode. I've written Sigma and Tamron about it, but they said they don't know about the problem yet and I should send it in. But I fear that when they don't know about the problem, they don't have a solution and I'm waiting weeks to get them back. The Nikon 35mm resp. 50mm f/1.8 work fine.