with a sensor that has an approximately equivalent pixel density (1.6 MP/cm squared vs 1.5 for the 5D), it's not surprising that the 6 megapixel Pentax aquits itself well from the same tripod position. However, with an "apples to apples" comparison, the CMOS sensor still gives the Canon 5D the obvious edge even though the Pentax fixed focal length lens is probably slightly superior to the Canon zoom.

The crop from the 5D: