Some of the Nikons and Minoltas have a slide feeder as an accessory.
If your film is mounted and you aren't too particular about processing them individually, you just load it up with 50....and go do some ironing.
If they're not mounted, there is a roll feeder, but I haven't seen it, gotta do 35 at a time I suppose.
If they're cut rolls, a flat bed is quicker it'll do more in one pass than a dedicated scanner.
Top quality consumer res is 4000dpi, but you don't need that unless you plan to print big.