I'd advise a proper Macro lens too.
Generally they're designed for as little distortion as possible and the greatest sharpness possible, the trade-off is generally a slower lens. You can use them for conventional subjects too - I have the original SMC Pentax 100mm f4 which I use as a plain 100mm lens on bright days as well as for macro stuff. Focus is a bit twitchy near infinity but it's ridiculously sharp even at f4, and brilliant for architecture.
I do have a slight crop with the K5, but if I rack the lens all the way back and squash the bellows flat, it is very little. I get probably 90% of the negative area, which is usually ok for what I need.
Looks like this is turning into a DSLR thread...
Then let's turn it back to an SLR thread . . . :whistling:
Using Kodak Portra 400.
I have used a Nikon PB4 bellows and the 55mm Nikon f/3.5 and 55mm Nikon f/2.8. These give good results for digitizing and making copy negatives. As far as quality is concerned when digitizing the DSLR gives better results than a 4000dpi scanner. I don't think you will be disappointed in the lens for slide copying. You can get the same results without a bellows (which is how I started out to verify the idea could work well). With the Nikon 55mm lenses you need an extension tube to reach 1:1. You will also need to get a light source behind the slide. A light table would work well. I use a flash behind the slide with the diffusion plexiglass in the slide copy attachment. Then getting the whole setup parallel will be required. If you have many slides to copy a bellows with slide copy attachment is definitely the easiest and fastest way. Once setup I can "scan" or copy a whole roll in about 15 minutes.
I have lots of slides I would like to copy but have been delaying doing with my Nikon scanner. This seems like to perfect solution, as well as if I need to make a B&W print from either a slide. I have the Nikon set up already. Cool.