Start with the understanding that either you are
- shooting 24mm x 36mm slide/neg to FF size sensor, or
- shooting 24mm x 36mm slide/neg to APS-n size sensor, or
- shooting print to FF or APS-m size sensor
#3 is the simplest, you merely need to 'shoot close', do not not need necessarily 'macro' (1:5 reproduction, or larger)...fitting even 4x6" print to FF sensor is only about 1:4.23 reproduction (fit 152mm long image onto 36mm), or about 1:6.8 reproduction (152mm long image on 22.3mm)
#2 requires that you have macro capability for about 1:1.59 reproduction scale
#1 requires that you have macro capacility for 1:1 reproduction scale
In any event, you need good illumination. With a print, a light source to each side (left, right) at about 45 degree angle to the item being shot. With neg or slide, a diffuse source of even light trans-illuminating the neg/slide being shot. And a tripod or copy stand to mount the caemra at a fixed distance from what you are shooting.
Adrian, in the next post, states correctly that I got #1 mixed up with #2 (now corrected)