The Sigma 2470mm f/28 DG DN ART uses a noiseless stepping motor for autofocusing The AF speed is good although it doesn't reach the levels of the Sony 2470mm f/28GM Manual focusing works "by wire" This works reasonably well in reallife situations although we have seen more precise implementationsA 2470mm f/28 lens is the workhorse of choice for a ton of photographers and filmmakers, offering a versatile focal length range and a wide maximum aperture They can be quite expensive, however,The Sony FE 2470mm f/28 GM would be an obvious comparison, but it costs more than twice the amount of the Sigma 2470mm f/28 DG DN Art lens Just in monetary terms alone, you would expect the Sony version to be in a different league, so it's more viable to compare the Sigma to the Tamron 2875mm f/28 Di III RXD Sigma 24 70mm F2 8 Sony E Mount Review Don T Buy The Sony G Master Here S Why Youtube Sigma 24-70mm f2 8 dg dn art sony