Pentax KM Camera - Manual (Page 15)

USING CONVENTIONAL SCREW-MOUNT TAKUMAR
LENSES
Conventional screw-mount Taku mar lenses (both Super-Takumar
and SMC Takumar) can be easily mounted onto your camera by
attaching them first to a Mount Adaptor K. Use of the Mount
Adaptor K does not affect any aspect of normal lens function
except as regards the following two points:
1. Due to the difference in coupling systems, the automatic
diaphragm will not function.
2. Full-aperture metering lenses will function as stop-down
metering lenses.
P.S. This can also be used with the Pentax Digital cameras to use
thread mount lenses. Change the camera to manual mode and
press the exposure lock button to obtain an exposure reading. You
need to press the exposure lock button each time you fire. This
checks the exposure should it change even slightly.