Scanning 35mm vs Medium Format Scan Resolution Issue
 

There are scanners that can scan 35mm film at say 4000dpi. However, when putting in a Medium format size piece of film/negative the scanner can only scan at 2500dpi. Why is this?

It seems that if you can scan 35mm film at 4000 dpi, then you should be able to scan medium size film at 4000 dpi also?

Am I missing something?

It's likely the distance of the scanner from the film plane. Does it zoom out any?
Even if that's not it, it's almost always a reason based on physics. Something is X at a size, but can only be Y at another size -- yet two aspects are identical.

The same is true of bodies, lenses ... pretty much anything when it comes to optics, cameras or not.

I'd have to know more about the scanner. They vary quite a bit.