it is a great thing when you do not have time or want to bother with tripods for each shot (with other people or maybe want to see everything and yet still get as solid photos as you can and do not have time to tripod up all shots).Agreed on that, I think a 16-50 f4 with IS would be an ideal outdoor lens for hiking for example, especially if they can keep the size and weight similar to the 17-40.