see also:

• photography main index
• a nice guide by by Mark D Segal & Todd R Shaner to using your camera to photograph film (pdf)
• https://petapixel.com/2012/05/18/how-to-scan-film-negatives-with-a-dslr/
• petapixel's tutorial on using a camera to photograph film
• Negative Lab Pro software for post-processing color negative film images

• 35mm film negatives or slides often only hold about 8-10mp of data (6×6 MF slides probably give 24-36mp) so any current digital camera has enough resolution to maximise this as long as your technique and the lens is good, and accurately focused and exposed.
• slides and negatives are shot with emulsion side to lens to get the best sharpness
  • you are looking at emulsion side when letters at edges are back to front, and also the emulsion side is darker with a slight structure visible in light
• ensure light source does not hit the camera side of the film nor the camera lens
• for medium format, you can consider taking panorama style individual sections and stitching them for higher resolution images

• manual exposure
  • use the base ISO for the camera for best dynamic range capture (most are now ISO 200)
  • if using flash:
    • set shutter to x-sync speed and aperture to optimum for the lens and system (f/5 for Micro Four Thirds and f/8-11 for full frame)
    • set flash to manual and adjust to give good exposures
    • keep flash at constant distance to avoid variances in exposure
  • if using available light:
    • adjust exposure manually with histogram to expose to the right
    • set self-timer on to avoid camera shake
• white balance for color negatives
  • this can be difficult given their orange cast, options include:
    • just take a custom WB of the blank leader negative, but this results in tonality issues because the white balance adjustments are too extreme for optimum blue channel tonality
    • alternatively, use a blue light source (preferably matched to compensate for the orange mask although a 80B filter may suffice), then do a custom WB

• a downside of using Micro Four Thirds system is that the sensor is 4:3 and thus you don't use the whole sensor for a 3:2 slide or negative, plus traditional 35mm film copiers are designed for full frame cameras not a 2x cropped sensor camera, nevertheless, many people use these cameras without issue.
• use manual focus with magnified image view for accurate focus
• Pekkapotka's technique
  • Olympus m.ZD 60mm f/2.8 macro lens attached to the tube from a Dörr Slide Duplicator kit, but one could use other slide copier kits
  • optimum aperture appears to be f/5
• Using the Olympus OM-D E-M5 II Hi Res mode for 40mp scans of medium format film
  • uses a iPad as light box style light source and a plastic refrigerator food container as a translucent spacer on which to mount the film holder
  • even using a Olympus m.ZD 75mm f/1.8 lens instead of a macro lens, this setup gave 12x faster, and sharper, more detailed images with less dust and scratches than when using a film scanner with its glass near the film