With the Epson without stitching... it's only about nailing flatness/focus.
The X5 resolves 2600 effective with 3000 scans, so 0% MTF at 2600, quite a surprisingly low value for such an expensive machine, and if scanning 4x5" without stitching you have 0% MTF at 1800 or 1700. It is totally impressive for 35mm, but for LF having to stitch to go beyond 1700... after paying $16.000...
Cycles/mm at extintion is a very important metrics describing optical performance, the rest of the optical performance is close related, in this case.
The X5 scans always have around the same 60MPix effective not matering much the format size for regular formats (35mm, 6x9cm, 4x5") (it varies depending on aspect ratio, a longer frame delivers more, 6x12 delivers twice what 6x6, of course).
Suposing that a lens like the Sigma ART 70mm resolves less than 30MPix effective (may it more?), this would be your limiting factor for 1 shot scanning, the more you shift the more you'll approach that value. The ART has 50lp/mm at 50%MTF.
But with the DSLR you can stitch crops for "unlimited" performance.
IMO what math says is that the DSLR will be superior to the X5 if stitching, a practical test should show that.
Bookmarks