First of all, there is some variability within the same designation for each camera. For example, the *istDL default setting "Bright" is substantially oversaturated.....even beyond most point and shoots. The resulting images almost look toyish and therefore I always use "Natural" and it seems to render output much more close to "real life".
My understanding of the K-r (though I can't vouch for this....mine is being shipped!) is that the Bright setting is only slightly punchier than the Natural, so there may be more practical usage for the various settings.
Also, I would think there would be differences involving the other settings mentioned (contrast, etc.) that might affect each camera in the Pentax line (different types and sizes of sensors, how jpeg's are processed, etc.) Some of those settings might affect the image tone on a more subtle level, but a combination of differences could still be noticeable (not to mention how different lenses might react). Since you didn't mention which camera you own, it might be difficult to give the proper feedback accordingly.
Regardless, you may not ALWAYS get consistent results "in camera" (though the Pentax DSLR's are very good at getting as close as possible) depending on not just settings....but environmental conditions as well. So if your desire is to get a particular shot to look a certain way regardless.....you either have to be patient and wait for conditions to be more accomodating, learn more about how to manipulate the camera to adjust to the environment given (filters, experimenting with settings, etc.) or.....do a little post processing now and again.
Similar Threads 
