Initial photographs with a SIGMA 75-250mm f4-5

I discovered this SIGMA ZOOM 75-250mm f4-5 'multi-coated' lens at a pawn shop in Phoenix for $15. Research of SIGMA's production shows this lens to be of 1981-vintage.  With the only issue being a slightly 'sticky' axial barrel movement to zoom the lens mechanically and optically were in very good condition.

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]