I agree on all points with you, but I'd like to share one more set of graphs which better illustrates my initial comment about sharpness of files from ZD.
I shot the same target using Mamiya 645AF 55mm F2.8 lens.
To complete the illustration, here are
1. an updated composite chart of all targets,
2. the MTF charts measured from the tests with this lens,
3. a comparison to probably the best second sample which is D800 with Nikon 50mmAF-D F1.4 @5.6.
4. and the same, but animated for easier comparison
I am puzzled by Sigma. My previous impression on its sharpness when using it on D700 was much better. I may need to repeat this test on Sigma 105mm which I also have.
However, based on my prior use on D700, Sigma 70mm was sharper than Sigma 105.
I am also quite happy with the performance of my 13-year old zoom Nikon 28-70mmF2.8 which I used primarily with 35mm format in the past years!
I am so impressed with 50mm Nikon prime, I got it for free back in 2000 when I purchased Nikon F5 for $1000 right on the street for cash:) This lens was simply included!
I'd use it for my studio work, if not for the field curvature.
ZD with 55mm lens gives outstanding sharpness, but, ironically, I don't use this focal length frequently.
Nikon 60mm performed significantly better in this test than I expected, as other images I shot with it were rather lacking contrast and soft. I may need to look into the reasons why.
If that gets resolved, I may use this lens for my studio work, since it is flat field.
D800 system is certainly more versatile feature-wise, can deliver acceptable sharpness and is significantly less prone to moire, as most lenses are struggling with sensor resolution:)
ZD gives consistent sharpness, compatible Mamiya lenses are excellent and some are outstanding. Moire can be a significant issue even with not the sharpest lenses in the lineup, e.g. Mamiya 150mm F3.5) But above all, I love how Mamiya shutter sounds:)
I also enjoyed this discussion, thank you for your help with the charts!EDIT:
I am a bit confused by the results from the quickmft program: I re-shot ZD+55mm@F8 at a closer distance.
Strangely enough, the MFT was significantly changed - I am not sure then how reliable these graphs are... any thoughts?
Here is comparison (right click and view image for undistorted view):