I don't recommend using a copy lens... it's cheap... but so are most copy lenses and you will find a marked degradation in quality.
If you have a lot of slides/negs, I would recommend a dedicated film/slide scanner... how much you pay will depend on what you want to do with the images, ie, will you be wanting them for professional use, home printing, or just to view on a PC. You can pick up dedicated film scanners quite cheaply on Ebay etc, though I would suggest that you stick to the main names, ie Minolta, Nikon, Canon, Epson.... Like a lot of things, you get what you pay for!
Something with a resolution of around 2820 dpi would be great for just home use, and printing up to A4.
For professional use you'd be looking at something around the 5400dpi mark...
The new generation hybrid flatbed paper/film scanners are also worth a look at, quality is nearly up there with dedicated film scanners, but the older generation ones will show a marked degradation in image quality. Again, you get what you pay for, and again stick with the big name brands.
Things to look for... "Digital Ice" is a dust and scratch removal tool that works quite well, though sometimes causes a little softening of the image. "Fare" is Canon's version of scratch/dust removal tool... Both work well and can save you hours of cloning!
Buy a pair of white cotton gloves, and a set of plastic tweezers for handling your negs and slides... nothing worse then A3 fingerprints!
If you only have a few to do, it might be worth getting them scanned for you rather then buying a scanner. You usually pay per image, and price depends on scan resolution. For example we charge 25p for a straight 2820dpi single pass scan of a 35mm negative/slide,(minimum of 20 images) or £1 for a single pass 5400 dpi scan, (minimum of 5 images).
Feel free to message me if you need any further help!
Primarily it's for home use but viewing some of my processed prints more closely I find some images that I would like to look closer at.
Rejects with bad processing etc where I may be able to correct & improve with photoshop.
So definately not proffesional but if I find any gems I may well take you up on your package.
Since I posted I have purchased a FujiFV10D second hand. It only has a res of 640 by 480 but fits the purpose.
Thanks for your help.