Originally posted by Ivan J. Eberle Is also a great scanner. Be aware, though, that films shot with best 645 lenses can still handily out-resolve even it, by about 30% (greater linear resolution).
Before I added 645 to the mix, I already owned what is arguably the best dedicated 35mm consumer desktop film scanner, a Minolta DiMage Scan Elite 5400. It has greater than 100 lp/mm resolving power. The 5400 dpi files from it are so close to the linear pixel dimensions of what 645 yields from the 9000 ED (~70 lp/mm) that I can't justify the expense of a 9000 ED purely for 645.
So if you want to replace 35mm with 645 for other compelling reasons (ergonomics, bigger viewfinder, b&w negs that are bigger), go for it. However if you're going for the greater detail, and scrape everything that's there off the film, you may be disappointed to find you need to get into much higher-end scanning than what is commonly available to noticeably out-resolve what can relatively easily (and inexpensively) be achieved from 35mm.
I'm not quite sure I understand this. A scan of a 35mm frame at a nominal 5400 dpi is 35% larger than a scan at 4000, but a 645 neg or slide has 270% more area than 35mm. How can that be the close to the same? 645 lenses generally resolve more poorly than the best 35mm lenses, so those negs should actually work better on a lower resolution scanner, if resolution is really the issue.
The 9000 scans at 4000 dpi in my experience exceed the capabilities of most film. Perhaps my eyes are fooled, but 4000 dpi scans appear to resolve every grain in a 645 negative and resolve grain well even in a 35mm Kodachrome 25 slide.
According to PopPhoto, the Nikon actually tested out at 67 lp/mm and the Minolta at 71 lp/mm--both excellent, but not much different in practical terms. The Nikon and Minolta are both scanning at dpi that are close to three times their actual resolution. I am not sure that pumping more dpi into a scan of a smaller film renders a scan that is equal in quality to a much larger film at a slightly lower resolution.
MF scanning is not without its problems. Some of my first shots with the 645 were less impressive than I expected, much as you described in the above post. However, I found the biggest quality factor in MF scanning is not the resolution of the scanner, but film flatness. Close examination of my scans revealed that the grain at the edges was not in sharp focus. An expensive glass carrier from Nikon cleared that up nicely, but introduced other issues, including 4 more surfaces to keep clean. Achieving a critically sharp, clean, well exposed and corrected scan from edge to edge, without dust or Newton banding (even with AN glass) requires careful work that rivals the effort I used to make in the darkroom.