Yashica ML 42-75mm f3.5-4.5

     This is my first experience with the Yashica ML 42-75mm.  I was not impressed holding it for the first time.  It has a significant amount of plastic and feels more like a Cosina  than a Yashica ML.  Focus dampening is very Cosina like and the one touch zoom mechanism is not smooth at all.  It is a lightweight lens.  I mounted it on the 6D and shot a couple of quick pics.   My assumption that it was cheap changed quickly.  It is easy to focus despite being a f3.5 lens.  Zooming is not smooth but the lens does hold position well without any zoom creep.
It is very sharp.  At 42mm f3.5 it is sharp.  At 75mm f4.5 it is very sharp.  Corners are sharp f4.5 up.  At f3.5 it will vignette with the most noticeable falloff occuring at 42mm.  Vignetting is not so apparent at f4.5 and up.  You will also see a barrel distortion at 42mm.  It will also flare at 42mm f3.5 if pointed directly into a light source.  Flare is very well controlled at all other aperture and zoom settings.  Fringing can also be seen at f3.5.  It is gone by f5.6.  Contrast is excellent with good control of highlights.  Color rendition is warm and color separation is subtle.  Bokeh appears smooth yet defined at wider apertures.  This is a good lens.  It will produce sharp and pleasing images.