DxOMark scores these lenses in 5 categories. When comparing Sony 500mm/4 to Nikon 500mm/4, using both companys' flagship bodies, a99 vs. D800, Sony has better scores in all 5 categories. Yet, Nikon gets a 25 score overall and Sony only rates a 22? What is going on that is not being shown here?
Readers should also compare the scores on the Canon 500/4, which seems to also come out short in the overall comparison after winning in 4 out of 5 categories, with a tie in the 5th.
Not sure that I want to continue to use DxOMark as an "unbiased" resource any more.