Today I got my 17-40 4L lens and I have been trying it out. It's really sharp! So glad I got it. Here are some totally unedited shots with 100% crops. There was NO post processing at all except the cropping. Straight out of camera. All are ISO 100, 125/1 with different aperture.

17mm f/10


100% crop:


17mm f/11


100% crop:


40mm f/11


100% crop:


40mm f/4


100% crop:


And here is the lens itself.