Originally posted by CWyatt Here's a 100% crop of part of an image, near the edge, not really in the corner, f/8, 21mm, 1/350. Tree is 'in focus'.
Of course, we have to take your word for it that this really is in focus. Also, hopefully not a windy day.
Since you mention the K10D, I'm actually guessing you are talking about the *old* 18-55 design, though, not the current design. I also say that because the current design improves on on the borders quite a bit. The cactus images I posted shows quite a bit more detail even in the extreme top right (the corner that closest to being in focus), although i don't have a 100% crop handy to prove this. So really, this discussion is probably a bit moot - we're taking about different lenses.
But even if so, it would still be useful to put this into context. As you said, that is a 100% crop, and you're looking at an edge. If someone looks at this image without fully comprehending what that means, they might get the idea that everything they shoot will look that bad. But of course that's not the case. That's just the worst small piece of the image along the edge, blown up far bigger than anyone would normally ever be viewing or printing images.
Not saying that other lenses aren't better - of course they are. But why not post the full image that crop came from, so people can get a better of what we're really talking about here? We're not talking a whole image looking like that - we're talking about the extreme edges looking like that if you hold a magnifying glass up to the print, or print a poster and examine it as closely as you would a snapshot.