Canon 60d/ 50d and EF-S are garbage and soft? Explain this.

snapperZ wrote:

I don't own this lens but to me the surprising thing is how well it performs at most focal lenghts and f stops. Looking at the resolution graphs at photozone the high level of performance suggests it's very well designed for such a zoom and the small amount of softening at f8 onward is due to diffraction. This softening is very slight but will look a bit more obvious on a 7D or 60D.

The theoretical diffraction limit on a 7D starts at f6.7 IIRC but its entirely dependent on pixel density NOT sensor format. You will still record extra detail well beyond that slightly arbitrary limit compared to a lower density sensor though it can look progressively softer at 100% view despite recording more detail. You really need to compare prints at the same size to make a valid comparison. Of course not every lens copy will be equal and AF accuracy probably varies even more.