Originally posted by paperbag846 Yes that is funny... and I haven no idea why that happens
Pentax changed the way the aperture arm in the camera moved. On the original K-mount cameras, the aperture arm was either up or down. That's all that was needed; the lens was controlled by the aperture ring.
They needed to get clever when they wanted the camera body to control the aperture. On these bodies, the arm can move in precise increments. They had to change the lenses too, so the camera's arm movement translated into the correct aperture blade movement.
Getting all this to work, pretty much as designed, 25 years later on DSLRs is a pretty amazing feat.