LaserSoft Imaging

I've read some previous postings about sharpness in transparencies, but they don't seem to address why the Epson TWAIN Pro 2.1 scanning program scans slides better than SF5.5. I've tried using Unsharp Masking in SF, but the Epson scans still come out sharper, & without any dithering in the highlight areas. Now, on 4x5 transparencies, the SF scans are better. I'm scanning at 1600 dpi for both. Any info would be helpful. tia.
david

Sharper Scan with Expression 1640XL

Have you checked that the focus control is in the proper postion?

https://www.silverfast.com/show/focus-control/en.html

Also for this scanner the upgrade to SilverFast Ai6 with lots of powerful functions is recommended for this scanner.