>>4121293If the neg is blurred on the sides when looking via a loupe the lens is fuckered. If it isn't, your neg isn't flat while scanning.
>>4121330I'd say 24mp and up is nice. Nice getting 6000x4000 350dpi scans. Depends what your goals are with the scans. If you won't be printing you could do 16mp easily. Most important part is getting a good macro lens to use. Don't try to use a normal lens + a bunch of extension tubes.