Certainly you remeber the boring evenings with slide shows of your friends or of Uncle Jack with hundreds of pictures of the Greece or Bora Bora vacation. Yes your plan was to destroy this damned slide-projector;)
Today everyone use their notebooks and their beamer, but this isn't much better;)
I had an old slide-projector, a Porst visual 302 out of the 1970s. But he was broken. The only thing which I've kept is the lens of the slide-projector, a 2.8/85mm.
I've thought that I can use it for something.
Some days ago I've tested it at my Praktica LTL3, but I've needed a spacer to have the right focal distance.
I've screwed a hollowed lens (a Yashinon DS-M 1.7/50mm) as a spacer on the camera.
Of course, you can't screw the slide-projector lens on the camera or on the hollowed lens, you must hold the slide-projector lens the whole time when you take a picture and certainly you can't set the slide-projector lens.
But so you can use the slide-projector lens in the "normal" way or as Reverse Lens for Macro Photography.
As Reverse Lens:
Pictures with the Reverse Lens technique at 1/125s and f-stop 2.8. I'm sorry but I don't know the enlargement factor, perhaps 1:2 or 1:1 or larger.
The film was a Fuji Superia XTRA 400:
"the macro effect 01-03", brasil, 2010
Here is Part 2