If your camera has an option for ISO 200 (or lower) go for it, the lower the better really. Some images generally come out grainy if it was a fast moving scene or its just very large. Most of the time when I take a pic I'll resize it slightly smaller than RAW to avoid that.
Anyway think yourself lucky xD I have a manual macro lens (ex canon, ie it will only work on manual setting) and I have to put in the aper,F,ISO etc.. all manually - and I can only see the results when the pic is taken =P