Dynamic Range Optimization feature
As it is now common the K2000 offers a Dynamic Range optimization feature. It is called D-Range and is designed to expand highlight range. The mode can only be used at ISOs 200-3200 because it appears to work by underexposing the image by 1 stop and then pulling the shadows and mid-tones up. (The exposure is the same as for 'normal' ISO 200 but the sensor appears to effectively be being run as if it were ISO100, meaning the brightest areas of the sensor do no overexpose).
Whatever changes the system is making, they're included in the RAW file (probably via a metadata tag) in such a way that they can be interpreted by a variety of RAW converters, so you are not tied to Pentax's own software to see the benefit in RAW. The included software doesn't allow you to simply apply D-Range to RAW files. Pentax Photo Laboratory, which is based on Silkypix, features a highlight compensation slider which unfortunately does not appear to alter the image in any way.
As you can see in the graph enabling D-Range at ISO 200 gives you approximately one stop of additional highlight range. The sample shots below demonstrate what difference this makes in real life. We exposed both shots to get some detail on the brickwork of the dark tunnel. Naturally this results in an overexposure of the buildings you can see outside. As you can see in the crops D-Range managed to recover quite a bit of highlight detail that would otherwise have been lost.
|D-Range disabled||D-Range enabled|