Okay. Well, you know this already, but... how you meter can make all the difference. Suppose e.g. that you average metered this. The camera will see all that backlighting and get tricked into a shorter exposure. Which will then cause you to underexpose her and the foreground... hence more grain and less optimal colouration there. There is a good dose of contrast in this scene and I'd guess you could easily have 3-4 stops difference in the optimal exposure for the foreground and for the background. This is a case where avg. metering can really screw you.
Did you bracket this scene perchance?
Keith, I did not bracket this as it was more of a snapshop but I did indeed use avg. metering which I use to use quite often before I've begun turning to my hand-held almost all the time now.