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).
Nikon D90 vs. Pentax K20D
Nikon D90: Nikkor 50 mm F1.8 lens, Aperture Priority, ISO 200
JPEG Large/Fine, Manual WB, Default Parameters (Standard), Active D-Lighting off) Self-Timer (with delayed exposure)
This shows two extremes: the gently processed, slightly soft D90 output and the very sharpened, high-contrast default output of the K20D. It really says more about the different manufacturers' opinions about what their customers are looking for, than in does about the underlying technologies. Again, the differences between cameras at their base ISO settings are so subtle that it's only by comparing the RAW files that we can get an understanding of any differences between captured data (though the K20D's superior resolution will be making some contribution).