You can consider several things when scanning 120 film.
Let’s assume, for a moment, that mechanical issues are absent.
- Mismatch of the source and sensor aspect ratio lead to losses compared to the sensor’s nominal megapixel figures.Scanning 6x6 with an FF sensor wastes at least 33% of sensor pixels. Leaves about 30 usable Mpixels of the Z72. 25% loss with a GFX, leaving 36 Mpixels of the GFX50.
- Work around the mismatch with stitching or Lightroom’s Super Resolution? Tried it with scans of 645 negatives and the gain/effort favours Super Resolution in my case. Printing reaaallly big asks for stitching.
Mechanical considerations
- Vertical setups need to be super-sturdy
- Attach the lens rather than the camera unless the lens is really light
- Keep the lens as close to the column as possible to avoid elastic movement
- Keep the rig as small as possible - a long column tends to vibrate longer
- Horizontal setups can be less demanding
- Try to connect the film carrier to the lens (think Nikon ES-2) rather than a baseboard
- for better rigidity and to eliminate stray light hitting the negative
- The backlight should be (much) bigger than the negative to prevent falloff
- Make things adjustable. Prefer positive- over non-positive locking (screws over friction)
Some of these considerations have gone into the rigs that you’ll see here:
Digital Camera Scanning - Film Community at Negative Lab Pro and
https://forums.negativelabpro.com/t/lets-see-your-dslr-film-scanning-setup/
and other theads.