I will be making a bizarre statement here by stating that the Tamron 180mm Macro is sharper than the Canon 180mm Macro. I have tested both lenses and can confirm this to be true. The Canon 180mm simply lacks the sharpness and contrast that the Tamron can produce. The best part is, the Tamron is cheaper than the Canon by a far margin. It is hard not to get the Tamron if you know this fact. Maybe many Canon shooters out there would disagree with me but that is fine. After all, gears are not what make our photograph good, only our eyes and vision. You also need to know that every lens will produce its own color and it has individual characteristics. It is like a painter choosing his pastel. All you need to do is find one that suits your photography well and go with it. I chose the Tamron.