Yashinon DS 50mm f1.9
The Yashinon DS 50mm f1.9 is an excellent overall performer from f2.8 up. Contrast is noticeably low from f1.9 to f4 but it is excellent at f8. Bokeh is reasonably smooth and color shifting in out of focus areas is minimal. Color rendition is slightly cool. Shadow detail is excellent due to the soft contrast below f8. The DS line was a compromise between the DX line, which had great bokeh but not great sharpness and the DS-M line, which had rougher bokeh but excellent sharpness and contrast. If your shooting jpegs, turn up your contrast a tad and shoot f2.8 or higher. F1.9 is just too soft.