My new 28-75 is showing up today but I just noticed it is Tamron Autofocus 28-75mm f2.8 XR Di LD Aspherical (IF) version. I know there is also the non-Aspherical version as well. Is there a big difference between these two - have I ordered the wrong one? On Fred Miranda's site, there is a big difference in the ratings - both do well but the "non" version is rated higher.
thanks!

