Thank you very much for an extremely interesting comparison.
At the risk of appearing shamelessly self-serving (gotta take risks sometimes), I would like to recommend that you consider using Imatest for future tests. Of course, Imatest is not a substitute for real images, but it can provide superb quantitative comparisons between cameras and lenses. It can measure sharpness with far greater precision than you can estimate by observing images; you can measure exactly how much they differ.
Before I go too far, here is some background. Imatest is an affordable program for measuring digital image quality (especially sharpness, which is measured as MTF). It involves photographing and analyzing simple targets: slanted-edge for sharpness, step charts, the GretagMacbeth ColorChecker, and a few others. Here are some key links:
Home page:
http://www.imatest.com/Image quality factors:
http://www.imatest.com/docs/iqf.htmlSharpness (explanation of MTF):
http://www.imatest.com/docs/sharpness.htmlHow to test lenses:
http://www.imatest.com/docs/lens_testing.htmlA few points:
Imatest is particularly good for measuring lens sharpness (though it does so as a part of system sharpness; it can't measure lenses by themselves). All you need is to include a simple slanted edge in the photo (several if you want to see how performance changes at the edge). It's easy to find the optimum aperature and see how much sharpness is lost at non-optimum apertures. Lenses vary the most when they are wide-open. Most tend to be diffraction-limited at small apertures. The meaning of"Small aperture" (where sharpness starts dropping significantly) depends on the format. It's roughly f/11-f/16 for 35mm format; f/16-f/22 for larger formats.
Imatest produces excellent results regardless of image contrast-- you don't need to normalize image contrast, which is the correct thing to do for making visual comparisons. Normalization is built into Imatest.
Imatest shows exactly what sharpening does. It is valuable for comparing different raw converters.
Imatest can compare color accuracy using the ColorChecker images that will be on the disk. (It can also measure noise in the ColorChecker patches.) See
http://www.imatest.com/docs/tour_colorcheck.html .
Imatest can measure dynamic range, but the measurement requires some care. Dynamic range for cameras in this class can be quite high: 11 to 13 f-stops, enough to push the limits of the Stouffer T4110 transmission step chart, which has a maximum density of 4.0 (about 13 f-stops).
Enough for now. There's lots of detail on the Imatest website. Yes, it's "pixel peeping," but it's done right and carried to the limit. Although I designed Imatest for serious photographers interested in testing their camera and lens systems (like most readers of this site), it has been widely adopted by the mobile imaging (i.e., camera phone) industry. Yes, I know, camera phone images are pretty bad (and they'll never be as good as large formats; size matters), but they will get better. About 600 million of the little things will be sold this year, making camera phones the fastest growing industry in history, at least for a year or two. It doesn't feel too bad to dominate image quality testing in that industry, especially since it happened by accident.
