The photographs below are untouched initial images to get a first impression on the performance and operation of the lens.
The mount is Konica (KR) and it was secured to the NX1 with a KR-to-NX mount adapter.
My initial impressions of these first photographs were very positive for sharpness and I wasn't even using a tripod for the 250mm images.
SIGMA ZOOM 75-250mm f4-5 [SN 913147]