Tamron 70-210mm f4-5.6 Adaptall 58A

     This adaptall lens was made at a time when plastic was being used to cut costs by most lens makers.  It is very light, not well made and quite clunky.  The focus/zoom ring is not dampened well,  Focusing is difficult to nail and almost impossible to maintain.  It's a shame because the optics aren't bad.   I took some quick pics fom the window.   I shook a little on some of the pics.  Sharpness is acceptable.  Actually, it is better than many lenses which cost much more.  Contrast is low at 210mm.  Color rendition and saturation is a bit flat but not bad.  There is noticeable fringing in high contrast scenes. but you may not see it in standard prints.  For $20 it is a good usable lens optically, but the cheap feel may be a turn off for you as it is for me.