Camera Memory Speed has completed their exhaustive test of 113 SD cards in the brand new Canon EOS R. The UHS-II performance of the camera is quite good, with the max write speed hitting 182MB/s from the Lexar Professional 2000x UHS-II Rev E 64GB.
The methodology behind the testing:
Write speed is determined using the buffer full condition. This begins when the buffer has reached capacity and the camera is unable to sustain the full continuous frame rate. In this condition shooting is limited to the rate at which the buffer is emptied. During the buffer full condition the total data written is known in addition to the time between shots. This method eliminates the need to use the card access light. Because the interval between shots is not constant for this camera, an extended test time of one minute is used for each card. A regular pattern in the shot intervals is observed and the first and last shots are chosen according to the repeating pattern.
The five best performing cards:
- Lexar Professional 2000x UHS-II Rev E 64GB 182.7 MB/s
- ProGrade 250MB/s UHS-II V90 64GB 181.5 MB/s
- Lexar Professional 2000x UHS-II 64GB 181.3 MB/s
- Adata Premier One UHS-II V90 64GB 181.1 MB/s
- Lexar Professional 1800x microSD UHS-II 64GB 180.3 MB/s
The three worst performing cards:
- SanDisk Ultra 80MB/s 64GB 15.0 MB/s
- SanDisk Ultra 90MB/s microSD 200GB 17.4 MB/s
- SanDisk Ultra 80MB/s 32GB Card 2 18.2 MB/s