Canons first mirrorless full frame camera, EOS R, is equipped with the RF mount for the very first time and supports 4K video, featuring EOS 5D Mark IVs image sensor and DIGIC 8 image processor. Unfortunately, only one sd card slot (UHS-II) is available.
The EOS R achieves the highest speed with UHS-II memory cards, but these are not necessary at all. Filmmakers should, however, pay attention to an U3 or V30 classification, otherwise video recordings in 4K mode might interrupt. In our table, all 4K-capable memory cards are marked with a corresponding -logo.
Memory Card Lab