Fernando, what camera/lens combo do you plan to use to photograph greater than 1:1 on a full frame camera? I know the Laowa macro lenses go to 2:1, which would work, but not most others.
I owned the Scan Elite 5400, but it finally died. Also had the Minolta Scan Multi Pro (4800 ppi) but sold it when I started using a DSLR with macro lens and compared the results. I’ve also had numerous images of mine drum scanned by service bureaus for commercial use, so I’ve been able get decent comparisons between various scanners. So much, of course, depends on the scanner operator and the software. Many of these older film scanners, such as the Minoltas and Nikons, rely on older software, or Vuescan, which simply doesn’t offer the same control as current raw software such as RawTherapee. For me this is a huge factor.
When I did my tests on 24 vs 36 mp, I selected very sharp 35mm images on Fujichrome Velvia and Provia 100, with fine detail and compared them side by side on the computer screen at the same magnification. The differences were negligible if present at all and I’d have a lot of difficulty determining which camera was used for each scan in a blind test. So much depends on the software, including the sharpening.
I also did some tests on scanning medium-format film using a Nikon D800 and a D810 to see what difference the optical low-pass filter makes. In these tests I found any difference to be negligible. I recognize that photographing real-world scenes, as opposed to film, would show a difference, as is evident by samples in Dpreview.
That said, I should note that I’m doing most of my 35mm scanning, both for my own work and for other pro photographers, with a full-frame D800 and Nikkor 60mm f2.8 G micro lens. At 1:1 (or very close to it as I want a bit of wiggle room for focus) it still shows a bit of the slide mount, which helps to centre the slide and ensures I have the whole image area. With the D800 I can just crop this out after and still have plenty of resolution.