The Canon EOS R3 underwent DxOMark's testing, and scored a high point of 96. And…
Since he tested some of the most regarded Canon lenses, his test is particularly interesting. At the end of the day, only one of the tested Canon lenses had an acceptable performance (and obviously not comparable to native Sony lenses). All lenses have been tested using the FotodioX Adapter for Canon EF and EF-S lenses. How to interpret this:
One minute after turning the camera on, the AF worked better than the first few seconds.
- Canon EF 85mm f/1.2L II: only manual focus works
- Canon EF 100-400mm f/4.5-5.6L IS II: works well only up to 300mm, no focus during shots
- Canon EF 135mm f/2L: only manual focus works
- Canon EF 70-200mm f/2.8L IS: lens with best performance with a7RII AF
- Canon EF 70-200mm f/4L IS: only manual focus works
- Canon EF 400mm f/2.8L IS: doesn’t work well
- Canon EF 400mm f/5.6L: doesn’t work well
- Canon EF 600mm f/4L IS II: doesn’t work well
- Tamron 150-600mm f/5.6-6.3 (Canon mount): only manual focus works
These are pretty disappointing and sobering results. You can see how some of the lenses performed in the videos above and below. Don’t believe the hype: if you own Canon glass stick with a Canon DSLR! I wrote an opinion piece about the Sony a7RII.