Canon currently has a handful of scanners designed for working with photographs and film negatives. The latest addition to the group, the CanoScan 8400F, isn't remarkably different from the 8000F it replaces, but it offers home archivists and graphics pros nice performance enhancements--at least on paper.
Upside: If you have a lot of negatives and transparencies to digitize, the 8400F will be a great help. As with the 8000F, you can crank out batch scans at up to 12 frames at a time. The 8400F incorporates Canon's Hyper CCD III system, which features a 3,200dpi sensor (the 8000F's was 2,400dpi). We liked the 8000F's photo and film scans, so we're hoping the 8400F's will be even better. Canon also claims to have improved the built-in retouching technology.
Downside: The 8400F looks like a decent--if fairly inconsequential--update to Canon's scanner lineup. Instead of buying the new model, you might want to grab the older 8000F, especially as prices drop.
Outlook: We can't felt but feel blasé about this update since there's not a lot here. On the other hand, Canon is smart not to mess too much with a product that's done fairly well. We'll let you know if the 8400F lives up to its line once we test it out later this summer.