Well, the Flextight makes 6900 dpi effective for 35mm film, this is an insane amount, and it makes +4.0D for Velvia... this is its sweet point, as the format gets large it shines less.
I've no doubt that a DSLR scanner can reach 10,000 dpi effective, it would require stitching even for 35mm, but it can be done with a bare $35 Nikkor-EL 50mm reversed, which is an insanely good lens.
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