Improve your workflow with blazing-fast transfer speeds.

I started making the switch to mirrorless cameras a little over a year ago when I bought my Canon EOS-R. The camera has been a champ and it made me hungry for the Canon EOS R5 when it was released last summer. I even sold my Canon 5D Mark IV in anticipation of the camera upgrade. Well, a little over a month ago, I was able to get my hands on the holy grail of mirrorless cameras (in my opinion). Along with my camera upgrade came an upgrade in recording media, too. With the 5D Mark IV, I had two card slots — a standard SD card slot and a Compact Flash card slot. I made good use of both and the dual card slots were a feature I was happy to see on the R5. Canon did make the leap and upgraded the Compact Flash slot to a CFExpress card slot to accommodate the CFExpress memory cards. I immediately turned to my friends from SanDisk and picked up a 128GB SanDisk Extreme Pro CFexpress Card. Along with it, I got a CFExpress card reader since my other card readers are completely incompatible with the CFExpress card.



The CFExpress Card Type B features read speeds up to 1700 MB/s and write speeds up to 1400 MB/s. Users can expect to get low latency during high-speed recording and blazing soft speeds that can deliver Raw 4K video. The card is backward-compatible with XQD cameras that adopt firmware enabling CFexpress, the card includes both RescuePRO Deluxe Recovery Software and a limited lifetime warranty for added peace of mind. 

In order to take advantage of more efficient workflows, you will need the CFExpress card reader also by SanDisk. It works with USB 3.1 Gen 2 speeds and is optimized for the CFExpress card. It comes with a 0.5-meter USB-C cable and features a 2-year limited warranty.



Right off the bat, I noticed the size difference between the CompactFlash card and the CFExpress card. The card actually looks a little like a standard SD card and a CF card had a baby. It’s somewhere in between the two card sizes, but it has the metal body like the older CF card does. It’s a very sturdy card that I discovered cools off very quickly when it gets warmed up (more on that later). When you put it into the camera, it has a very gentle bounce-click that photographers are accustomed to with memory cards. That same tactile bump is present when you put the card into the card reader. As far as performance goes, I tested this card (and its card reader) a few different ways. 


First, I recorded some video onto the card using the Canon EOS R5. I did a few clips in standard 4K and then one clip in 8K. My goal was to have some media to transfer from the card to a computer using the card reader so that I could time how quickly the transfer took. After capturing the video and removing the card from the camera, I noticed the card was hot to the touch. The R5 has a known heating problem when shooting 8K video, so I wasn’t surprised about the noticeable heat exchange. The card registered 94º and the card slot on the camera registered 108º using an infrared thermometer. The card did cool off rather quickly and it didn’t seem to harm it at all. Canon EOS R5 users are well-aware of the over-heating issues when shooting 8K video and it’s nice to know that this card seems to handle it well. 


As far as the timed testing goes, I had several different case studies to observe. The results are listed below. 

  • Test A: Transferred 4K video file from CFExpress Card to 13-inch 2016 MacBook Pro. File size 16.18GB. Transfer completed in 32.19 seconds. Transfer rate 0.50 GB/s or 500 MB/s.
  • Test B: Transferred 4K video file from CFExpress Card to 16-inch 2020 MacBook Pro. File size 96GB. Transfer completed in 119 seconds. Transfer rate 0.80 GB/s 800 MB/s.
  • Test C: Transferred 8K video file from CFExpress Card to 16-inch 2020 MacBook Pro. File size 2.8GB. Transfer completed in 3 seconds. Transfer rate 0.93 GB/s or 930 MB/s.
  • Test D: Transferred 147 photos at 45 megapixels each from CFExpress Card to 13-inch 2016 MacBook Pro. Total file size 8.54GB. Transfer completed in 22.16 seconds. Transfer rate 0.38 GB/s or 380 MB/s.

After completing those test cases, I decided to run one more series of timed tests to test the cable specifically. I happen to have a USB-C cable that is capable of USB4 speeds so in order to make sure I was getting the absolute fastest transfer speeds, I swapped the cable that was included with the card reader for this USB4 cable for one last speed test. Because the reader only supports up to USB 3.1 Gen 2 speeds (10GB/s), I knew that I shouldn’t be able to get the maximum speeds from the Accell cable, but I knew it would allow for the maximum speeds that the reader would provide. I transferred the same file I used in Test A and got the following results. 

  • SanDisk Cable:  Transferred 4K video file from CFExpress Card to 16-inch 2020 MacBook Pro. File size 16.18GB. Transfer completed in 15.90 seconds. Transfer rate 1.01 GB/s or 1010 MB/s.
  • Accell USB4 USB-C cable:  Transferred 4K video file from CFExpress Card to 16-inch 2020 MacBook Pro. File size 16.18GB. Transfer completed in 16.01 seconds. Transfer rate 1.01 GB/s or 1010 MB/s.

 I was happy to find that the file transferred at the nearly exact same speed no matter which cable was being used. In order to test the read/write speeds, I used two different pieces of software – Blackmagic Disk Speed Test and the AJA System Test. I ran both of these tests using the 13-inch 2016 MacBook Pro. I ran the AJA test three times – each time I used a different codec protocol – and the Blackmagic test once. After the tests were completed, I averaged the read and write speeds and came up with a result of 469.98 WRITE and 816.70 READ. This is far below the specs stated for the CFExpress card, which is 1700 MB/s READ and 1400 MB/s WRITE. It is possible that the read/write speed was slowed down while testing by the USB 3.1 Gen 2 connection between the reader and the computer. 

  • SanDisk-CFExpressCard


I have been very impressed with the overall performance of the CFExpress card and its reader. I really liked having the dual cards in my Canon 5D Mark IV and I’m really excited to have access to that again in the EOS R5. It does appear that in order to get the best out of this card, you will need to have up-to-date hardware/software at your disposal. Right now the CFExpress Card is $199 for 128GB. There is a smaller capacity available, but it’s still $109 for 64GB. There is also a 256GB and a 512GB card option with the 512GB being nearly $600 (at the time of publishing). Do I feel that it’s worth the investment? If you shoot a lot of photos and videos, then yes, it is worth it. You get a super-efficient card that transfers incredibly fast and having two cards working together helps with redundancy while you work. The only thing I would have liked to see included is an SD card slot on the card reader so that you wouldn’t have to carry multiple readers with you.

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