Recently I came across a second hand Nikon bellows unit together with the slide copier attachment. These are the old models PB-4 and PS-4. I use these with my N8008s (F801s) and AF 105/2.8 macro lens together with an SB-26 flash extended to about 12" behind the slide copier with the SC-17 cord. I have started looking at what sort of results I can get when copying old slides to print film.
I focus the setup using f/2.8 and then move the aperture ring to the f/8 setting (effectively about f/11 to f/16 depending on enlargement, I copy medium format slides as well). The camera is set to aperture priority and the flash to TTL with the 20mm diffuser in place, it works every time.
About the same time I was lent a zoom slide copier of brand Lioner. This attaches to the camera via a T-mount and the flash is used the same way as above. The zoom allows from 1:1 to 2:1 enlargement.
The first step was to compare the convenient Lioner copier to the slightly more fiddly Nikon setup.
This is the way the Nikon equipment looks when attached to the custom made frame to hold everything in place, see my other article (page in construction still) about how that was made. The camera body shown is not the one I use for copying work.
I judge the relative resolution of the above portions by examining the porthole and the rivet detail there.
A side effect of the experiments has shown that by using slides and then copying with some degree of magnification, a cheap zoom lens substitute is available. For instance, I could take a slide of a sunset or full moon with my maximum lens of 300mm then copy it to another slide or to print with the jig set to enlarge as much a possible (3.5x currently) so the result would be a slightly grainier shot but looking if it were taken with a 1050mm lens. OK all this could be done easier if I owned a good film scanner, but currently I want everything to be on slide or prints.
Also for no effort on my part, my photo processing shop can enlarge the centre portion of my negative up to about 1.7x onto the standard 4"x6" print. This method extends my 28-105 zoom lens to 178mm and my 75-300 lens to 510mm. If you want to go the other way, that is make a wider view than the lens you own, then the only way is to take a few photos with the wide angle lens and join them with scissors and tape. Or scan them and join them with photo stitching software.
If you are contemplating buying a digital camera then don't worry about the wide angle end of its zoom, concentrate on the tele behaviour, then simulate a wide angle lens with the stitching software (see my links page).