The Canon 8400F is of course a competent flatbed scanner - its claim to fame is the additional capability as film scanner. It comes with adapters for 35mm and 120-type film strips and 5x5cm mounted slides, and provides resolutions up to 3600 dpi; and that at a price substantially below those of dedicated film scanners. The question is, how well does it work with films.
The user manual on the CD tells you that you have to start film scanning from the included "ArcSoft" photo editing program - this is not true. After installing the basic "ScanGear CS" software, it can be started from any photo editing program you already have on your computer. Even simpler, any scanning job can be started from the "CanoScan Toolbox", and the resulting file can be saved anywhere under an entered name.
ScanGear CS gives a preview of the inserted items on the left side of the monitor and offers various numerical selections and image adjustments on the right side. It exhibits somewhat of a "father knows best" attitude and won't let you enter just any numbers you choose. For example, it doesn't like 4x4cm super slides; you need to trick it by moving the outline borders with the mouse in the preview, rather than trying to type the numbers into the film size field. (Incidentally, there is nothing to prevent you from placing mounted 120-type slides without any special adapter on the platen in the location where they would be unmounted in the adapter).
The software offers image adjustments for brightness, contrast and gamma and can squeeze or truncate the histogram range (but apparently not expand). It does not provide independent adjustments for highlights - midtones - shadows, which would be useful to tame particularly contrasty slides. It is difficult to get the white balance right in the small preview pictures; my scans come out mostly too blue and need to be tweaked afterwards. (I would never go with photos from scanning directly to printing, which is another option of CanoScan).
With the color slides I have, the visual (apparent) sharpness of the scanned images does not seem to be different between 2400 and 3600 dpi; is about the same as with the HP S20 Photo Scanner (35mm only) at 2400dpi; and is not quite what one expects. Unfortunately, I don't have a microscope for a really meaningful comparison with the original. There is the nagging concern that neither of these scanners has a focus adjustment. How good is the depth of focus? Of course, the manual doesn't say. However, it is somewhat reassuring that scans of Kodachrome 25 look sharper than those of Ektachrome 64, which in turn are slightly sharper than those of the Ektachrome 100 films. It is also noteworthy that, on any given film, non-SLR cameras (i.e. without a moving mirror) on tripod result in sharper pictures than a SLR camera on tripod. So perhaps the sharpness one obtains is really limited by the camera and film, not this scanner. (This comparison is based on Ektachrome EPR in a Linhof with Schneider Symmar vs. an Olympus OM with various Zuiko lenses, comparing 1x1mm of film surface scanned at 3600 dpi).
Any clear disadvantages over a dedicated film scanner? The glass platen remains in place - another surface to collect dust and lint to be included in the scan. Forget about scanning negative film!

Recommended: Yes

Amount Paid (US$): 139.99
Interface: USB