Just bought a Nikon D610 and I can't get it to autofocus with my Sigma 105mm Macro. Mine is the 105mm f/2.8 EX DG OS HSM model which does autofocus fine on my older D5100. Other lenses will autofocus fine on the D610. First thing I did with the D610 was to update to the latest firmware. Can't think of anything else I can try? Anyone know if there's a known issue between this camera and lens combination?