Kiron 30-80mm f3.5-4.5

     It is built like a tank and weighs even more.  On the Eos M3 it is a chore to shoot with handheld.  It is impossible to hold it steady.  Having said that, I'm glad I found a good copy.  It is a good lens.  At 30mm f4 it is sharp.  At 80mm f5.6 it is sharp in the center.  Corners are below average at 80mm on the sub frame T2i.  There is no noticeable diffraction when shooting at f16.  That is very unusual.   At 30mm f16 it is a good landscape lens. At 30mm f3.5 there is vignetting.  There is also distortion at 30mm.   Fringing can be seen at all apertures in 100% crops.  It is correctable in post processing.  Bokeh is natural and tight.  Bokeh fringing can be seen in some situations and can be  distracting.  Macro is engaged by Zooming to 80mm, then focusing down to closest focus and then zomming back toward 30mm.  For this reason it is important that the lens does not exhibit any zoom creep.  That will cause your macro focus to shift.  That is why this lens' focus ring is a tad stiff.  it must be in order to resist zoom creep.  I had no problem taking 6 second exposures at f16 with the lens tilted down in macro mode, but if you come across a copy of this lens that exhibits zoom creep, you may want to let it pass.  Macro performance is good but not stellar.   I say that because macro mode is active from 30mm to approx. 50mm.   If you need to get in close you will need extension tubes and a focusing rail. Black and white is exceptional with this lens.   Contrast is very good at all apertures.   Color rendition is excellent.   Back lighting will cause contrast reducing flare.  Side lighting, however, does not produce flare.   If you can steady this lens and shoot at f5.6 thru f16 you will get excellent results.  I suggest getting one in your native mount so you can avoid dealing with a vibration magnifying adapter.