View in original size for detailed comparison. Both images were shot handheld within moments of each other. The Tamron image shows more noise. I have noticed this with images from this lens. This may perhaps be due to a lack of antireflective coatings on the elements of the Tamron lens. This would result in less light reaching the sensor, hence a weaker signal compared to the background noise. Other than that, there's not a lot of difference between these images. I know it sounds like heresy, but the center sharpness wide open (f/5.6) for the Tamron is similar to the center sharpness wide open (f/4) for the Canon L lens. The advantage of the Canon lens is this performance comes with an extra stop of light. That plus better edge performance, image stabilization, USM autofocus, much less CA, etc, etc. I'm impressed by the sharpness of the Tamron, but I'm glad I use the Canon lens.