I tried using slide duplicators on camera. It was very difficult to get illumination even, and everything about it was awkward. I got results, but it was not worth the effort. Instead, I bought at top-of-the-line Epson flatbed and got great results with ease. Common wisdom of the net is that flatbeds are useless for this task, but that is a good half-dozen years out of date. It certainly was true one time, but Moore's Law applies to scanners as well as everything else digital. My scanner will handle medium and large format film, as well as prints and even documents. It comes with an OCR (optical character recognition) program that has saved me considerable typing. It will also do batch scanning of negatives or slides.