The meter works in aperture priority mode for all lenses, including K, M and M42, however, in aperture priority mode, K and M lenses will stay wide open during exposure no matter what aperture you choose on the lens. No metering is available in manual mode,
Hopefully you add this "however" in your second message...
however, all aperture values can be selected, and the lens really stops down in manual mode during exposure or when DOF previewing.
Arnold
...while others talk about taking out the K and M aperture lever... They won't need to do so, then.
Andre --
