I recently purchased a flatbed scanner (Canon D660U) with the intention of getting a lot of my work on computer and cutting down on printing costs. The scanning resolution is 1200 dpi and with negatives it is ok but not fantastic. But with slides the focus is out and quality is terrible. Would it be better to make an investment and get a dedicated film scanner (looking at the Canon FS2710, the FS4000 is out of my price range)? Any advice on the matter or experience with these scanners would be welcome.

I have the FS4000 and I've been very happy with it so far....it does have a tendency to scan slides dark, meaning that I will sometimes lose detail in shadow areas. After some tweaking with the settings, updating the drivers and following some recommendations from this website, it isn't a problem any longer. I've read really good things about the FS2710 as well.

Several years ago I got a tamarac slide/film scanner that went to 1200 optical and 9600 or so software dpi. All I can say is 1200 aint enough on 35mm slides/negatives and the software sux. I had scan lines and abberitions in the image unless I turned the dpi way up with the software, which back then didn't work on a slow machine. Now that I have a fast machine, I don't scan film any more due to the purchase of a digital camera. However, I do have to say the scans from that Tamarac were good for digital work, just not to the level of a darkroom. I would think modern technology is better for slide/film scanners and I've heard good things about the canon ones. But I'm referring to the dedicated slide/film canon scanners, not the tray that comes in a flatbed. If you're asking whether or not a dedicated scanner is better than a flatbed with a tray in it, my guess is yes.

Oh, one more thing, the slides may be out of focus because of the thick paper frame setting them at a slightly higher location than where the negative would sit. Dedicated slide/negative scanners should correct for this by making a tray that puts the film at the exact right location in relation to the light tray. Best thing you can do is go to a camera/computer store (usually camera stores) and run some slides on the machine to see how they come out. There are some stores that have the scanners set up for demo purposes.

A small fraction of an inch on the height is enough to screw you up. As a suggestion... develop your own slides, cut them like negatives. Scan like negatives, and reverse them either in the firmware or in Photoshop. See if that helps. Sounds like you are kinda happy with your flatbed with the exception of the slides and I'd think that was a tray issue which the above workaround might fix.