Originally posted by EagleEye Which one in your experience is more durable?
K1000 and KX are completely mechanical except for a black needle in the viewfinder that shows you what the camera thinks the exposure should be.
The K1000 has a bracket shaped sort of like a backwards C, and thinks exposure is correct when the needle is centered in the bracket. There are no other viewfinder displays.
The KX has a blue needle in the viewfinder that moves with your shutter speed dial, showing you the speed you have set. When you put the black needle at the same place as the blue needle, your exposure agrees with the camera's meter. The KX also has a periscope that displays the f/stop from the aperture ring at the top of the viewfinder.
Either of them is virtually indestructible. There are no electronic things to go wrong. If the battery dies, everything still works.
The M and later series of cameras use battery power for the viewfinder displays. No battery, no camera. The MX, for example, replaced the KX's blue needle with LEDs.