I just purchased a Canon 17-40mm f/4L. I've been testing this lens at different focal lengths at different apertures. I mounted it on my 50D with aperture priority setting on a tripod with a cable release. I've read that this lens doesn't perform well at f/4, but to those who have this lens, I want to ask you a few things.
How's sharpness of your copy at 17mm at f/8? Mine is not sharp. Compared with my 10-22mm at 17mm at f/8, 10-22mm performs much better to me.
With the exception of focal length at 17mm, 17-40mm performs pretty well between f/8 and f/11, but the IQ declines from f/16. What are your experiences?
I've attached two images, first one was taken with 17-40mm at 17mm f/8, the second one was taken with 10-22mm at 17mm f/8. 100% crop center, no editing. I know it's usually user error, but I am trying to figure out if I have a bad copy. The reason why I bought this lens is because I want to upgrade to 5D Mark II in the near future.
Thank you for your input in advance!