Originally posted by disasterfilm The Sigma HSM/AF issues you've read about are firmware issues for the lenses which can be fixed with a quick trip back to Sigma. The issue is the body is reading the lens's EXIF ID and the current number is in conflict with other lenses - specifically lens ID 8.255 co-identifies as a 70-200 and a 24-70 (I think). .
8.255 is used for at least 6 lenses...
'8 255.1' = Sigma 70-200mm F2.8 EX DG Macro HSM II
'8 255.2' = Sigma 150-500mm F5-6.3 DG APO [OS] HSM
'8 255.3' = Sigma 50-150mm F2.8 II APO EX DC HSM
'8 255.4' = Sigma 4.5mm F2.8 EX DC HSM Circular Fisheye
'8 255.5' = Sigma 50-200mm F4-5.6 DC OS
'8 255.6' = Sigma 24-70mm F2.8 EX DG HSM
My Sigma 10-20mm F3.5 EX DC HSM also has a 8 255 identifier. It should be 8 11...My Sigma 150-500 has the correct identifier (8 15).