But, have you used the kit lenses as described above?

I’ve taken thousands of images with the old 18-55 kit lens (non-IS, the one regarded as worse than the newer one) and it’s worked perfectly fine. These were all taken with that lens and they’ve had exactly the same amount of sharpening as I use on my 70-200L f/4. Granted, images from that lens look better, but still…

Nowt wrong wi’em lad. No dramatic aberrations of any kind and the edits took me all of 30 seconds each in CS4. These are actually way, way sharper and cleaner than what I see most people produce with L series lenses of any focal length. I can’t bring myself to slate a lens I can get images like these out of. It’s not what you have, it’s what you do with it, and if you know what you’re doing then you can expect to get results like these consistently.

If you’re having such problems then you must have had a really, really bad copy. I’ve had two of these lenses and they’ve both given me results like these examples. I have to admit though, the little 50mm f/1.8 (if that’s the one you mean) is a cracker!

Paul