Are differences in lenses only seen at 100%?

Ray - thanks for the pics!  Your photos with the 24-85VR look really good at 2016 pixels.  I'm sure even printed at quite large sizes they would look good.  I see that you used the 24-85VR in Italy as a walkabout lens - this is what I was thinking of, since I'd be going to Europe quite a bit, plus I also have a trip to Boston in April.