Sven, I'm not familiar with your measuring system, but are you able to check the focal length at various focusing distances? Some internal focusing (IF) lenses are known to have shorter effective focal lengths at shorter distances. The FA 28-200 is around 180mm at infinity, but more like 110 mm at around 2 meters, as tested by Keppler at Popular Photography.
Most other Pentax lenses are much closer to the specified focal length. Thanks for the info, Sven, it is of interest. Pat White
