See my Pentax K1 wish list at B&H Photo.
Update Sept 2016: Pentax adds EFC shutter firmware update.
Shutter vibration aka shutter shake is vibration caused by the shutter itself, even if the mirror has been locked up. The Sony A7R suffered severe problems with shutter vibration, resolved with the 2nd generation Sony A7R II.
In general, the longer the focal length and/or the more unstable the 'rig', the more serious a problem shutter vibration is.
While the Pentax K1 uses an Electronic First Curtain Shutter (EFC Shutter) for its SuperRes mode (lack of it would render the feature useless!), neither the K1 nor its K3 II sibling offers and EFC shutter option for zero vibration exposures.
Without an EFC shutter, sharp images at certain shutter speeds are not feasible. So how does the Pentax K1 perform, at 140mm?
Tested using the Pentax HD PENTAX D FA* 70-200mm f/2.8 ED DC AW mounted using the lens tripod collar foot. Notes include confirmatory findings at 77mm and why 200mm could not be used.