« on: July 26, 2013, 10:50:27 AM »
I am a little confused. The Digital Picture review claims that this new S version shows a significant improvement in sharpness, and has the comparative test results to back this up. Yet the MTF charts and optical design for this lens and the previous version are identical. Also, Roger over at LensRentals (who I have a great deal of faith in) says: "the optics are identical" and consequently he wouldn't pay the extra grand for the new version.
What do you think is going on here?
Explained in article.
Roger, after tearing down both OS versions of the 120-300, said it appeared that elements in these lenses could be interchanged. The optical design seems unchanged. When questioned about this, Sigma replied that the 120-300 "S" has 2 FLD Glass elements instead of one. FLD glass has performance equal to fluorite, which is excellent.
So 2 FLD elements instead of one so better IQ.