If you get the Silverfast Newsletter you will find a quote from me in the current one.
The new multisampling feature in SF Studio appears in my testing to be a real breakthrough. ..
It would be hard to surpass the noise reduction of SF Studio.
My tests also reveal that with SF Studio you get the most noise reduction in RGB files (noise is virtually eliminated completely) even if you are looking for a grayscale image as the final product. So I am scanning 4x5 b & w negs as 48bit RGB files with 16 sampling passes and then converting them to 16 bit grayscale. The exact opposite was true with former SF AI 6. You would get much less noise with grayscale scans with SF AI 6.
Read here how SilverFast's phenomenal Multi-Sampling is working:
You should know that I have no relationship with SF. I simply buy and use and prefer their product for scanning. That quote refered to my initial tests with the Studio upgrade on an Epson 4990. I am currently testing the software on a Microtek 1800f. The quote was pulled from a posting I made on their forum which if you read the fine print, they have the right to use as they see fit.
Currently, I would modify the above statement by saying that 8 passes is usually sufficient and that with economy scanners like the Epson 4990 you need to do a dummy batch scan (1 pass) before the real 8 pass scan to heat up the negative so that it doesn't expand beyond the softwares ability to align the passes. Also with the 4990 I save the blue channel and convert it to grayscale, with the 1800f I save the green.