Below is an image quality comparison between four 35mm lenses - three high quality choices and an economy model. These crops represent a worst-case scenario - they were taken from the extreme bottom left of the frame from a full frame format Canon EOS 1Ds Mark III. The Standard Picture Style with a sharpness setting of "1" (very low) was used for processing these images in Canon's Digital Photo Professional. The plane of sharp focus should include the tree trunk in these examples.
Note that the Canon EF 35mm f/1.4L USM Lens frames the scene slightly wider than the others - crops from this lens are taken from just inside the bottom left corner to align the details in the crops.