II don't know if the illumination was different or not.
My guess is that the metering systems probably had trouble coping with the scene, which is why you see a variety of Exposure Compensation levels being used.
These exposure data no shown the illumination question?
ISO 1600 have been set. However, the ISO1600 of K10D in exposure compensation has been set at -1EV. This may be caused by illumination.
-1EV was to ISO elevated 1 multiple, namely ISO1600 turning to ISO3200,It is very unfavorable for K10D. This is basic knowledge of photography.
A100 exposure compensation 0EV.
In any event, A100 all is in the advantageous situation, Regardless of is the illumination or that exposure compensation. However, how the A100 results? Everyone can see.