E., I have a Nikon PB-4 bellows and PS-4 slide copying attachment to go with it. I haven't looked, suspect that there are similar slide copying attachments for the other Nikon bellows. IMO the PB-4's features look nice but are pretty useless, wouldn't recommend one. The PS-4, however, is very handy, has vertical and horizontal shift so allows reframing.
Originally Posted by E. von Hoegh
Strongly concur with recommendations to use a 55 MicroNikkor, add to that that they are probably best used for slide copying at apertures no smaller than f/8.
I've usually copied K14 slides onto a daylight type E6 emulsion, have always had problems with contrast gain and color temperature. Kodak used to make a low contrast E6 emulsion for slide copying, it is probably long gone. If I were to do it again, I'd probably use tungsten balanced E6 (if there still is such a thing and it can be found) and the right tungsten lamp. Copying K14 to K14 was very problematic, but since K14 processing has gone away its moot.
One other comment. The typical slide mount has an opening slightly smaller than 24 x 36. Copying a mounted slide entails getting some mount around the periphery of the copy (if shooting at 1:1) or slight enlarging. I always enlarged a little.