>>3291447You can see all the differences here:
http://www.buonaluce.com/S2PS.pdfThe 150mm PS lens was slightly redesigned.
The only practical difference is that the PS has half stop clicks, the S doesn't. You can use half aperture stops in S lenses, it just doesn't click.
The only optical differences, almost imperceptible of course, is that the S has better bokeh and a tiny bit faster, and the PS slightly more contrasty wide open.
I went with the PS because it was quite cheaper, and for its purpose (portraits) better bokeh and works better than higher contrast wide open.
I don't have any bokeh whore shots on my laptop, but just as a reference, the S I wouldn't call the S version lacking in contrast or sharpness anyway.
