1600 iso? That's a bit crazy. Great shot. It's a bit grainy, but I only point that out because I'm not as big of a fan of grain. I'd be curious to see this same image as a night shot with a faster iso.
Usually I try to use less than 1600, as I don't like the effect either, but it was raining A LOT and I didn't really want the camera to stay under the heavy rain for too long and that is why i did 1/6 speed and not longer. I don't know if you were talking about this Anyway, about the iso, 1600 is the max on my camera!