There's confusion between 'system' resolution and lens resolution. 35mm zooms might typically produce a 'system' resolution limit of 60 lp/mm, but the lens itself must surely be capable of much higher than this.
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I can't see much point in pinning one's hopes on an even smaller format than 35mm.
I was talking about lens resolution only.
The figures I quote for 35mm pro lenses are for lens resolution, based on "MTF50", the lp/mm at which MTF is 50%, as recommended by Norman Koren and others. For example,
http://www.normankoren.com/Tutorials/MTF1A.htmlgives an MTF50 of 61lp/mm for the Canon 28-70mm f/2.8L, one of the sharpest 35mm normal focal length zooms around.
I ignore the far higher lp/mm figures based on "extinction resolution" at which a very high contrast target is barely visible: those numbers correspond to resolving only 2-10% of true subject contrast, and so are of little relevance to human perception of a normal image.
Clearly the "one-piece digicam" test results are "system resolution", but the lens resolution is at least as good, and as you say only slightly better, since lenses are probably the main limit there.
The figures I quote for them might be a bit optimistic as they are not rigourous "MTF50", but nor are they the maximal "extinction resolution" figures.
If anyone wants endless data on 35mm and medium format lens resolution, measured as MTF at various resolutions up to 40lp/mm, check out
http://www.photodo.com/nav/prodindex.htmlI pin my hopes on a somewhat smaller format than 35mm, probably no smaller than the Kodak/Olympus 4/3" format, because it could easily exceed the resolution needed by the overwhelming majority of photographers in a more convenient way: enough resolution for ANY SIZE of print so long as it is viewed "normally", meaning from a distance at least as great as the image size, so that most or all of the image fits into the field of view. Even with large murals and panoramas, the closest distance that makes sense to me for normal viewing is the short dimension of the print. About 3000 full colour pixels across a distance equal to ones viewing distance is all the eye can distinguish, pessimistically up to 4500 for Bayer pattern pixels. That is partly why 35mm lens MTF is typically measured only at up to 40lp/mm, which corresponds to just under 2000 lines by 3000 lines across the whole frame.
Thus I expect to eventually leave the bulky, more expensive lenses and other gear of larger formats (including 35mm format DSLR's) and their higher resolutions to the small minority of high end photographers who care about scutinizing small portions of the whole image, or who use primes and therefore more often have to crop significantly, or who need backward compatability with existing 35mm lenses.
P. S. I will also be happy to ditch the 2:3 aspect ratio of 35mm format.