Pros: Good reflective, very good transparency, high optical dpi
Cons: Software sometimes hangs up.
The AGFA DuoScan is a SCSI-based reflective and transmissive scanner with two scanning trays - the glass on top, and a slide-out tray for transparencies. Frames fit the inner tray to hold various film sizes. At the time we bought it, the DuoScan had the most professional-level capabilities of any non-production style scanner. It has a 3.8 density rating, which was exceptional for a scanner under $3k.
I am sorry to note AGFA's departure from desktop scanning. The DuoScan represented a solid effort to put the technology of expensive scanners (like the Horizon and its pricier cousins) into a more affordable package. Desktop scanners now seem exclusively focused on making a fast buck in the consumer market, leaving very little in what I consider the midrange.
This scanner does well with reflective scanning, especially if you don't rely on AGFA's software for anything but scanner-specific settings. (Leave the image manipulation to Photoshop you'll have better control anyways.) But the transparency scanning is even more exciting. Short of a dedicated film scanner, the DuoScan produces the best results I've seen from a desktop machine. If you scan a medium-format transparency with the correct film setting, the result will be an image 95% ready to go, requiring the merest touch of adjustment.
I scanned an 8x10 duplicate with no special settings in the scan operation and the image on screen was absolutely stunning. It has been an effective tool for anything 6x6cm and larger. Because it is a flatbed, scanning 35mm is only good for FPO purposes. The light bar cannot put enough light through such a small transparency to make an effective scan. Reflective scans on the DuoScan require more work, yielding very good detail definition but with some color bias, not usually a problem but a bother with old photos where the paper has yellowed. Every CCD has bias it's inherent to the technology - but I guess had hoped for less with 3.8 density and 16-bit ability. Reflectives come out pretty well once you become accustomed to this scanner (or have the expertise to build custom color profiles).
For imaging, this was the best scanner for the price. Operationally, it has some flaws. The AGFA software, first a TWAIN function and now a program (FotoLook) has always been problematic. Both tend to work fine for a number of scans and then suddenly freeze in the middle of a scan, or stop seeing the scanner entirely. Having used (and trouble-shot) our DuoScan with three different computers, I have a hard time believing the problem lies anywhere but in AGFA's software, or possibly onboard the scanner itself. Last year one of the motors conked out. We returned it to AGFA for repair; they replaced some parts and it is back to normal.
One thing the AGFA software has performed well for me is de-screening. When scanning printed material, Fotolook does an admirable job of compensating for visible line screen and screen patterns. Even the old TWAIN plugin did a fair job with sources 85lpi or higher, provided the original was on decent paper. AGFA's descreening often provides better results than Photoshop.
This is not a scanner for the casual or impatient user. In the right hands, the imaging quality outweighs its quirkiness, and the DuoScan provides truly professional quality at a fair price.