Found this beautiful little lens on an Argus/Cosina STL 1000. As I understand it, Cosina manufactured most of their own lenses, except a few 1.2 and 1.4 lenses made by Tomioka. In test shots, this looks like a great combination of features for a nifty fifty lens. At 1.8, images are sharp in the middle, with a slight glow to the highlights, and going to somewhat soft around the edges (even with an APS-C digital sensor). Stop down to 5.6, and sharpness is great from edge to edge. I would guess this is the standard kit lens for this camera. It’s a winner on digital!
f=1.8 ~ nice close focusing, and interesting bokeh!
f=1.8 ~ adding a little macro helicoid distance for even closer shots.
f=5.6 ~ nice crisp details!
f=11 ~ looking for star highlights ~ you can check out the sun at the bottom of the image. Nothing much to see here…