For example, the Hasselblad X5 scans 35mm negs at (true, non-interpolated) resolution of 8000dpi, but 4x5 negs at 2040dpi
http://www.hasselbladusa.com/product...xtight-x5.aspx

The Epson v750 uses its high quality lens to pull 6400dpi from negs up to 4x5, and then switches to its dedicated worse-resolution lens when it scans 8x10 negs to give you 4800dpi.

What's the point?