Is your version of that lens compatible with the Sigma dock and, if it is, have you checked for firmware updates?I have recently purchased a Sigma 70-200mm f 2.8. It has been working great on my D7100. When I tried to use the lens on my D600, I get a funky "flickering" of the AF info on the LCD of the D600 and no AF. If I turn the AF off, the flickering stops. Suggestions? TIA