I’m on several Canon EOS R5 mirrorless camera related blogs, and a question frequently comes up about what type of memory cards to use. After spending $7K on an R5 + battery grip + 24-70mm f2.8L, don’t go on the cheap with a $19.95 dollar store special CFexpress (CFx) memory card.
You’ve already melted your credit card, and your spouse hasn’t spoken to you for a month, so what’s another couple of hundred bucks for a decent memory card? That’s what your extra kidney can be sold and used to pay for the bill.
Seriously, the devil is in the details as they always boast about speed, usually the “read” speed. Who cares what the read speed is, as the problem is getting the data on the card and not pulling the data from the card.
Before buying the memory card, do two things. (1) Check the card specifications for the WRITE speed, and (2) check the camera manufacturer’s recommended memory card list. Click this link for the Canon EOS R5 Recommended Memory Cards.
An R5 CR3 RAW image file is about 50 Megabytes in size, and when you’re madly punching the shutter button, the poor R5 is struggling to get the last picture stored on the card. I know that Canon says their buffer holds around 150 images but give it all the help you can.
A card’s WRITE speed is the maximum data transfer rate that the card can accept incoming information. The write speed is never prominently advertised since the read speed is always faster.
The R5 allows the use of either a CFx type-B or SD card or both to be used. As an engineer, I am a belt and suspenders type of person. I always believe that if some is good, more is better!
My recommended configuration is to use a CFx card for RAWs and an SD card for large JPGs. This way, if god forbid, and my CFx card malfunctions, then I can at least fall back on the SD card with large JPGs.
I shoot in RAW mode all the time with a large JPG as backup for every shot. While I typically never use the JPGs, I put them on my NAS drive just in case. Also, a JPG is good as you can give the picture to someone for instant viewing. JPGs are viewable with typically any cell phone, tablet, or computer.
I don’t post-process JPGs as they are a “lossy” format or compressed. Every time a JPG is edited, it loses some quality as it gets recompressed. On the other hand, a RAW image is a copy of everything the camera saw when you took the picture.
RAWs are huge, and on the R5 about 50 MB in size, considering the sensor is 45 Megapixels. But when you post-process a RAW, it’s like starting from the actual image seen by the camera lens every time and not a compressed copy.
To handle raw files, the memory card must write the image at high speed to avoid overrunning the buffer.
For some reason, 64 GB cards write at about half the speed of 128 GB and larger cards. For this reason, I do not recommend buying less than 128 GB cards for the higher speed. My Sony Tough writes at 1,480 MB/s, and 64 GB write speeds are typically half or less of the CFx.
The fastest SD cards are about 300 MB/s, which is five times slower than the CFx card. I’ve never tested cards and have stuck with the highly-rated Sony Tough as I don’t want to take a chance on the memory card failing to work. Except for the snickers you get from putting a Sony card into a Canon camera. It’s almost heresy.
For SD cards, I use the Sony SF-G64T memory cards for my JPGs. It has a write speed of 299 MB/s. SD cards come in a multitude of speeds down to almost 10 times as slow. If an SD card is being used, make sure it is a fast writing card.
The 128 GB CFx card is overkill for most shooting sessions as it holds approximately 2,800 RAW images. The other night I did a photoshoot with 6 models and took almost 1,600 images. I went through four batteries in the camera and two batteries in my Godox flash but still had plenty of room left on the CFx card.
In closing, I’d like to say that your camera is only as good as the weakest link. You’ve spent a boatload of cash on the camera and lens. To my way of thinking, buy a decent memory card to store your images before uploading them to permanent storage.
The model pictured has nothing to do with the story beyond the fact, I like the image and need to use any justification to get you to read the post.
Vegas Camera Guy 