This is my test set-up for making hi-res "scans" of 4x5 negs and transparencies. Light source is an iPad Mini with a blank white screen. Negative/transparency holder is a magnetic Lucite block 4x6 picture frame from Crate & Barrel. Camera is 36 MP Sony A7R with Canon EF 100mm Macro lens in dumb Fotodiox NEX to E adapter (lens preset to working aperture of f/5.6). Position negative/transparency on top of one of the 1/2 inch thick lucite blocks, place second block on top to sandwich frame together with internal magnets. Set camera on tripod parallel to lucite frame in front of iPad (do not stop down too far or iPad screen pixels will show). Take 10-12 overlapping exposures for stitching. Composite the frames for final image which will be about 250 MP.
Sample below from a Type 55 neg. Original was 255 MP derived from 12 stitched images.
TMAX 100 4x5 film processed for transparency. Original was 280 MP, also from 12 stitched images using setup shown above. Click image below for file that is 25% of original size.