A 20 Mpix Foveon is not enough for 24x36mm.
76 lp/mm at the sensor would be good enough for any lens except an Otus mebbe. ;-)
Huh? If that was the case, then we wouldn't see any more detail in our photos when we step up from the SD9, SD10, SD14, or SD15 to the SD1 Merrill, but as you know Ted, even when using a zoom lens, like the 17-50mm f2.8 EX OS there is
a significant amount of extra detail in those Merrill images.
Huh? How do
you measure "detail", Scott?
. . . or were you just joking?
Nope. I realize that numbers other than MP are anathema to your good self - but may I offer, apart from the Otus, the Sigma 65mm DG DN which goes just over 80 lp/mm at
f/2.8 and
f/4 in the center, which a 20MP full-frame Foveon would almost match and would certainly beat at all other settings or away from the center of the lens.
See for yourself :
https://www.lenstip.com/600.4-Lens_review-Sigma_C_65_mm_f_2_DG_DN_Image_resolution.html
I think at this point you're just being impractical, and shutting your eyes to the obvious Ted.
Gee, thank you, Scott! After all, what would
I know about anything?

DP1

dp2 Quattro
Those are crops from these images at Imaging-Resource:
https://www.imaging-resource.com/PRODS/DP1/FULLRES/DP1hSLI100.JPG
https://www.imaging-resource.com/PRODS/sigma-dp2-quattro/FULLRES/DP2QhSLI0100H.JPG
Much more detail is visible in the image from the Quattro, as you and anyone else can see.
What's missing from your point is that the DP1 brought closer would render the same amount of detail on the circular slide rule and probably sharper. All you have shown us here is that the Quattro has a higher pixel density.
Ummm . . . isn't that how more detail is captured? I mean that's how they did it with film, right? (i.e. more grains of emulsion in the same square of film)
Nothing like a fair comparison, eh?
Equally fair:
I'll ask again: "How do
you measure "detail", Scott?"
I don't, but I can look at two photos and see numbers or letters in one, while not being able to make them out in the other, and that shows me there is more detail in one photo than in the other.
Something tells me you're trying to say something, but I am not "getting" it. Can you just be less cryptic, and come right out and tell me what you're trying to say?
Just jumping in here, to muddy the waters: at the pixel level, the older sensor will likely deliver better color resolution with the same amount of detail. Quattro sacrifices color resolution to increase detail resolution and even when you view Quattro lo-res images the loss of image quality is seen, relative to the older sensor.
This is a problem with Quattro, but whether or not it actually exists is controversial.
Well, this brings to mind the comparison post made by you Tom, which showed a photo from a Sigma camera with an old sensor, and another, basically identical photo (other than what looks like a slight difference in exposure), from the SD Quattro in low-res mode. They looked identical in all ways to me. Even the finest details looked the same to me. Surprisingly even the color looked virtually exactly the same to me. Here is that comparison (for those reading along):
https://www.dpreview.com/forums/post/58888373
Do you remember those?
Viewing those photos again, I see that the focus looked to be slightly more distant in one vs the other (i.e. the trees in the background appear to be in focus more in one shot vs the grass in the foreground appearing to be in better focus in the other shot), and the Quattro photo appears oversharpened to me. I do find the exposure looks the same in some parts of the images, while it looks different in other parts, and that makes me wonder what happened.
One thing I look forward to is being able to compare images from the fp-L to images from the upcoming camera with the "60 MP" full-frame Foveon sensor, using the exact same lens. THAT should be interesting.