Don't be fooled by claims that the 50D has no real resolution beyond 10MP cameras; the real reason for pixel-level softness of many sample images is due to the lens and/or the technique. The 50D is ready, willing, and able to have better pixel-level contrast than the 40D and earlier, because of weaker AA filters.

This is a 100% crop (original pixels) from the 50D, when viewed at "Original" size on pbase.

The lens is the Tamron 90mm f/2.8 macro.