All my large format work was passed on to the clients, so I can not test. However, a number of years ago, I chose the Epson 4870 which was top of the line at that time, because of its reputation with medium-format scanning. I really wanted the Nikon 9000, but just could not justify spending six times as much for it. My expectations for the Epson were quite low and I felt genuinely depressed as I walked home with it. It was common knowledge that flat-beds were next to useless for film.
As a test, I used a 6×7 negative, shot with my Linhof on ISO100 film in full sunlight. About as perfect original as you could find. Any weaknesses of the scanner would be blatantly obvious, and could not be blamed on a flawed original. It looked strangely great on the monitor in Photoshop, so I made a 13×19 print.
I really could hardly believe my eyes. If I spent two days in the fume-room and blew away a full box of colour paper, I could not have made a better print. Needless to say, several more prints followed immediately.
Shortly thereafter, a colleague was launching a new web magazine and invited a bunch of shooters over for a launch party. I brought along a small selection of large prints, slapped them onto the kitchen table under the brightest light in the house and said that they were done from medium format negs and chromes. I asked the group to tell me how they were scanned. The consensus was that they had been professionally drum-scanned at a top service bureau. When I revealed that they were done on a flat-bed, there was a chorus of "OMG!!!" Later, I found out the host of the evening gave away his Nikon to a cousin and bought a 4870.
Vincent Oliver - a respected reviewer and shooter at
http://www.photo-i.co.uk/Reviews/scanners_page.htm when reviewing the current Epson V700 and V750 did a direct comparison with a Nikon 9000. He found that when viewed at 100% on the monitor, the Nikon showed a slight edge in crispness as would be expected. However, he also found that just a small bit of sharpening applied to the Epson made the two scans indistinguishable. The 4870 was followed by the 4990 and now the V7x0 duo. If for any reason the 4870 wore out or broke down, I would have a V700 before nightfall. On the other hand, the 4870 still serves me well enough that I see no reason to trade for the newer machine. I really doubt that the difference in a big print would be visible, and if visible, certainly not significant.
A large format neg or chrome is far less challenging than medium format or 35mm, so one would expect it to be a breeze to produce extremely high quality prints of enormous size, given scanning and Photoshop skills and access to a large format printer. The current model has a holder for two 4×5 sheets and a positioning guide for 8×10, which I am sure would also work fine with 5×7. I would not even think of hesitating to use my current scanner, or the current new model for the task.
