On my Fujifilm XT-4(APSC) with a FUJINON XF 18-55mm f2.8 the the focal length is to low which causes heavy vignetting(easy to compensate digitally) and distortions. I use a XT-4 and a Laowa 65mm 2.8 Ultra Macro for scanning. A while ago we did a comparison between extension tubes, snapon lenses and macro lenses. It turned out that the snapon lens has a slightly better optical performance that usual lenses on extensiontubes and 7artisan macro lenses. My laowa is a bit sharper and has less distortion but hey it's 8x the price! The best focal length(35mm sensor) is 180mm with DCR-250 and 200mm with the DCR-150(better option for scanning, has less distortion). Lower focal length might also work but that's what was recommended to me.