Lately, there has been a lot of talks comparing the 18-70DX with the 17-55DX. Everyone appear to have an opinion but no one bothers to post a sample. So, I decided to give my 18-70 and 17-55 some workout. The following images were shot on Gitzo 3530S, BH-55, Mirror Up, in manual mode (exact same shutter speed, aperture & ISO) at 5600 degree Kevin white balance, from the exact same point. Both shot at 55mm - the difference in frame coverage is because of exit pupil/pupilary action. My observation is that there isn't too much difference on the full frame but when you look at the 100% crop you can see the difference. I won't comment on which one is better. It is for you to decide. However, bokeh is definitely better on the image shot with 17-55. BTW, these are "as shot" images - no post processing at all other than resizing and cropping (where applicable). I will shoot several more comparison shots over the weekend and post here.