warden
Subscriber
Flatbed scanners are calibrated to focus above the glass for film scans and on the glass for reflective (photos and paper). That accounts for the film holder.
Using an adjustable film holder (like BetterScanning) will help anyone interested find the best platform height for their flatbed scanner, and that level won't be on the glass if you're using an Epson. Having said that though, even if the film elevation is perfectly optimized the quality won't match a Nikon Coolscan. When I did a comparison the difference wasn't as large as what markbau is showing but there was a difference. My conclusion was to keep my Nikon for 35mm scans and use the Epson for MF.