I am shooting a Canon R7 and see reports of people using the MFO-3 on full frame cameras but none on crop sensor cameras. I would love to see examples of shots taken with a 100 macro, with and without the MFO-3. Thanks!

Not on a APS-C camera but I reported on using it with the Olympus 60mm macro (2x crop) recently:

If it works well on m43 and full frame it stands to reason that it will work fine on APS-C. The 100 mm macro is 160 mm equivalent on the R7 while the 60mm macro on m43 is 120mm equivalent, so I would suggest even more of a case to use it on APS-C. The specs for the field of view and working distance /magnification on Canon APS-C is on the MFO-3 port chart:

Google Docs

MFO-3 2025-08-27.pdf