Originally posted by Digitalis Although the 50mm f/2.5 macro is an older lens design, like the Pentax-SMC 50mm f/2.5 - they have common optical design elements, and both perform quite well when stopped down, even at f/2.5 they offer performance that is in ways superior to their faster f/1.4~f/1.8 brethren. Though I have to say I agree, they should have tested with more current lenses...but as far as EF mount 50mm lenses go, they could have done worse.
Personally, this is what they should have tested the 5DSr with.
In fact, in one case, Photozone tested several Canon zoom lenses that effectively double the performance score of the 50mm compact macro lens.
And so in this regard I'd say the 5DSr RAW studio testing results could have proven to be far better than what is shown here. :/
Canon EF 24-105mm @ 40mm, 3600+ score
Canon EF 24-70mm f/4 USM L IS @ 40mm, 3500+ score
Tamron AF 24-70mm f/2.8 SP Di USD VC @ 50mm+, 3600+ score
Voigtlander Nokton 58mm f/1.4 SL II, 3800+ score
That said, with this in mind, I'm thinking the 5DSr could potentially match the 645z with good glass insofar as resolution goes.