This is our standard studio scene comparison shot taken from exactly the same tripod position. Lighting: daylight simulation, >98% CRI. Crops are 100%. Ambient temperature was approximately 22°C (~72°F).
Pentax K20D vs. Olympus E-3
The Olympus E-3 is currently a considerably more expensive camera but one that has a pretty similar philosophy to the K20D. Both are weather sealed, both offer an excellent degree of customization and both have the same density of pixels (though this doesn't make any attempt to convey information about what proportion of each photosite is able to capture light). Although they share the same density of pixels, the K20D has a higher pixel count overall because its sensor is larger.
The results at the lowest sensitivity settings are extremely similar, though the Pentax is bringing more detail out of the sky in the pastoral scene. Again, how much of this is down to the K20D's relatively high default sharpening will be revealed in the raw conversion.