I used to work at a photo lab and we used to dupe slides that slightly smaller that 1:1. We had to fit the dupe the original slide to fit into a slide mount. From our set up, we used bellows and a Schneider enlarger lens. I didn't fully understand his question of copying photos 1:1. I also did work on a Bencher copy stand where we did use a 50mm macro lens. So you're correct.