Crop of previous image, at 100%, with no Picture control sharpening and about 87/5/0 USM or thereabouts, cropped and saved at about JPG quality 84. See previous full frame image for additional comments. I think this is very decent and on the basis of these tests (you don't see all the aperture brackets I shot) and real world shots I won;t hesitate to shoot this lens wide open with the TC17. You can't ask for more out of a lens.