Is my 1D Mark IV Sharp?

I've had my 1D Mark IV for 10-1/2 months and worry that it does not appear to be a sharp as my 1D Mark III. If I want Canon to look at it under warranty I don't have much time left. Here is a sample RAW image with no processing done on it except for uncompressed conversion to jpeg. (Shot with 500mm wide open on a tripod with single focus point in the center of the frame.) It seems sharp enough to me. What do you think?

Thanks....