resolution

I scanned some black and white films with HP Scanjet 4600. The pointed resolution was 2400 dpi or Less . See samples. I want to make rescan with Primefilm 3650u or 7250u. There is essential price difference. So please write if there are any essential advantage in quality when scanning with 7250u...

There seems to be a regular preoccupation with specks of dust inside a lens, both on the small ads here, and elsewhere. I suppose with the growing complexity of lenses (especially zooms) which have groups moving relative to one another (and thereby creating suction) it's an increasing problem...