I just bought a new 17-40L, and I'm happy that I didn't get it from ebay (the offers weren't good enough vs the current Canon rebate program) because the lens shows visible decentering - see attached 100% crops of bottom vs. top, my first thought was that the chart was tilted... but it wasn't me or the camera and now I'm going to get a replacement from Amazon.
I wonder how many times your lenses were exchanged (or how many copies you tested side by side) until you received a lens that was a good copy?
Looking at the crops, would you also have returned the lens, or is something like this to be expected and I'm spoiled by better lenses?
Btw, if anyone wonders: As far as I tested it the 17-40L is a good (landscape) zoom lens for the money even on crop, it's just the corners and that it doesn't reach max. sharpness wide open but needs to be stopped down a little to f5.6+
Edit: afma should be no issue @f4+ and my 60d doesn't have it anyway ... with this 17-40L copy I couldn't tell lv from phase af. The crops are of course focused with contrast af and shot on tripod with mirror lockup.
I wonder how many times your lenses were exchanged (or how many copies you tested side by side) until you received a lens that was a good copy?
Looking at the crops, would you also have returned the lens, or is something like this to be expected and I'm spoiled by better lenses?
Btw, if anyone wonders: As far as I tested it the 17-40L is a good (landscape) zoom lens for the money even on crop, it's just the corners and that it doesn't reach max. sharpness wide open but needs to be stopped down a little to f5.6+
Edit: afma should be no issue @f4+ and my 60d doesn't have it anyway ... with this 17-40L copy I couldn't tell lv from phase af. The crops are of course focused with contrast af and shot on tripod with mirror lockup.