Hi Roland, > I don't know how this is done, since when holding a lens in the > air and turning aperture - the aperture closes down. But on the > *ist, this does not happen.
There is nothing special with the *ist. It's like this on any camera. If you REALLY want to know look at the KMP --> Technology --> K-Mount Opetation ---> K-mount. Cheers, Boz
