The DG rating is just an improved coating on some Sigma lenses. It is said to improve digital performance by reducing fringing and reflections of reflections off of the sensor. I have the non DG 50mm EX Macro and it is very good on the DS, although the DG version may be in some way better.
Powell >I found, that according to Adorama, there are two versions of it >with the only difference that one has an additional designation "DG". >Igor
