Talley wrote in post #18448491
Exact same optics. Same mtf charts. Same groups. Same optics.
Refined everything else. New coatings is their way to say refined.
Interesting...do you have links?
Roger from LensRentals and The Digital Picture both want to retest to see possible IQ changes including possible improved variance among the MTF charts. Tamron apparently says says the elements are improved over the original but the big improvements are in the overall design, AF, IS, lens coatings, and quietness. Even if IQ is not changed it was already superb.