Most of the Yashica DSB and YUS 135mm 2.8 lenses I have seen have a 55 mm filter thread. This one has a 58mm filter thread. Here is sample picture of a plastic chicken shot wide open @f2.8 at ISO 200 after some quick editing. Not bad for a lens this old. It's also the perfect size. Without adapter it's about the size of the 18-55 kit lens just heavier. Out of camera jpeg without editing. ISO 200 f2.8. It's a little soft and you see some CA. Out of the camera jpeg stopped down to f4 at ISO 200. The sharpness drastically improves and still has good bokeh.