The Pentax K20D is compared to its predecessor, the K10D, below. All images below are 100% unmodified crops from their respective cameras. Both cameras were set on aperture-priority mode with fixed ISO and tungsten white-balance. Picture style is bright on both cameras. The remaining settings were left on automatic. Images were framed identically on both cameras which were mounted with the Pentax DA* 50-135mm lens set around 90mm. Note that despite the K20D having 44% more pixels, linear resolution is only 18% more, that is why the image on the left does not look that much bigger.

The most significant difference is that the K20D knows its white-balance much better than the K10D, which was one of the worst performers in that area. Still not perfect, but the K20D's white-balance is quite neutral. Colors are quite accurate with the K10D being spot-on and the K20D being slightly oversaturated. As mentioned in the review text, the K20D has one slightly over-saturated setting and one slightly undersaturated one. We chose the slightly over-saturated one here. Exposure is also very close but we can see that the K20D's tone curve is a bit steeper. Take a look at the yellow beads: the highlights are brighter on the K20D.

In terms of ISO performance, the comparison below show that both cameras have similar noise levels at all ISO levels. This is an excellent performance for the K20D which managed to keep the same noise levels despite an increase in resolution. Practically, this means that the K20D shows less noise for a given print or display size. In terms of image details, the K20D puts in an impressive performance. It seems that it has a lead of at least 2 stops over the K10D, despite not showing increased image noise.

The crops are only one version of the story because the Pentax K20D has customizable noise-reduction settings. The default is OFF, which is a bold move from Pentax and it clearly does the new sensor justice by leaving plenty of details. If we increase noise-reduction to Weakest, not much changes but beyond that the trade-off between noise and detail becomes apparent. So, with a few button pushes, we could have made the crops below show much less noise for the K20D but also significantly less detail. We left it as is, but it is the user's choice.