I'm working on building a film scanner using a dslr and a macro lens. The idea is to take many pictures of a negative and then combine them in software. Here's the prototype:
Currently, I manually slide the negative holder from spot to spot to scan the negative at 1:1 with a DX slr. For a 6x7cm negative, it requires 25 frames to cover. The results have been promising, but moving the negative carrier manually gets tedious, especially with bigger sheets of film.
As a result, I'd like to automate the negative holder movement, perhaps using an x-y lead screw stage with stepper motors. This seems similar to what some of you CNC folks are doing, although the load and rate would need to be much less. I'd probably size the stage to enable scanning of 5x7" and smaller negatives. With a lens at 1:1 magnification, the stage would need to move between 5mm and 20mm per sample area, depending on the orientation of the camera sensor. This doesn't have to be supper speedy, as taking a picture every 5 seconds or so would be fine.
Any suggestions as to the best way to do this would be greatly appreciated!