Best Memory Cards for Canon EOS 5DS & 5DS R Mark II
The Canon EOS 5DS and 5DS R are resolution monsters, producing massive 50.6-megapixel RAW files that can bring slow storage to a screeching halt. If you’ve ever been stuck staring at a “Busy” light while a perfect shot passes you by, you know that card speed is non-negotiable. I’ve tested dozens of configurations to find the perfect balance between the high-speed CompactFlash slot and the convenient SD slot. Our top pick, the SanDisk Extreme Pro CF, remains the gold standard for clearing that stubborn buffer.
Our Top Picks at a Glance
Best Memory Cards for Canon EOS 5DS & 5DS R: Detailed Reviews
SanDisk Extreme Pro CompactFlash View on Amazon View on B&H
When you’re shooting with 50.6 megapixels, each RAW file averages about 65MB. In my experience, the SanDisk Extreme Pro CompactFlash is the only card that consistently keeps up with the EOS 5DS R’s data-hungry sensor. It utilizes the UDMA 7 protocol to reach write speeds of up to 150MB/s, which is essential for clearing the internal buffer during a burst. While CompactFlash is an older format, it is physically much sturdier than SD cards—I’ve never had a SanDisk CF card casing crack in the field. The 160MB/s read speed also makes transferring thousands of high-res files to your computer significantly faster. The only real drawback is the price premium compared to SD, but for a professional body like the 5DS, the reliability and speed are worth every penny. It’s the card I keep in my primary slot for every landscape shoot.
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Lexar Professional 1066x CompactFlash View on Amazon View on B&H
The Lexar Professional 1066x is the direct competitor to the SanDisk Extreme Pro, and it often wins on price. In real-world testing with the 5DS, you’ll notice almost zero difference in burst depth between this and the SanDisk. It’s VPG-65 certified, meaning it can maintain a sustained write speed of 65MB/s, which is more than enough for the 5DS’s 1080p video capabilities. I’ve found Lexar cards to be workhorses in the studio, where I’m shooting hundreds of portraits a day. While Lexar went through a brand ownership change a few years back, the quality of the 1066x series has remained high. It’s a fantastic value if you need to buy multiple 128GB or 256GB cards to handle a week-long shoot without breaking the bank. The only minor gripe is that the write speed is slightly lower than the SanDisk at 150MB/s vs 155MB/s, but it’s negligible for most users.
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SanDisk Extreme Pro UHS-I SDXC View on Amazon View on B&H
The Canon 5DS and 5DS R have a dual-slot setup, but here’s the catch: the SD slot is only UHS-I compatible. This means that if you buy an expensive UHS-II card, it will still only operate at UHS-I speeds inside the camera. That’s why the SanDisk Extreme Pro SDXC is my go-to budget pick. It offers the maximum speed the 5DS SD slot can actually handle (up to 90MB/s write). I typically use this slot for “Overflow” or for writing JPEGs as a backup to the primary CF card. It’s incredibly reliable and dirt cheap compared to CF cards. However, be warned: if you set the camera to write large RAW files to both cards simultaneously, this SD card will become your bottleneck, slowing down the entire camera to match its speed. For methodical shooting, it’s perfect; for sports or action, stick to the CF slot for RAWs.
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Delkin Devices Power CompactFlash View on Amazon View on B&H
Delkin Devices has built a reputation among professionals for their “over-engineered” storage solutions. The Power CF card is their top-tier UDMA 7 offering, designed specifically for high-bitrate DSLR photography. What sets this card apart isn’t just the 160MB/s speed—which matches SanDisk—but the rigorous quality control. Each card is serialized and comes with a 48-hour replacement warranty in some regions. During my time using Delkin cards in humid coastal environments, I’ve found they handle temperature fluctuations and moisture slightly better than consumer-grade cards. It clears the 5DS buffer with impressive efficiency, allowing you to get back to shooting 50MP images without delay. It is more expensive than the Lexar, but for a mission-critical shoot where a card failure isn’t an option, Delkin is the brand many pros swear by. It’s a premium card for a premium high-resolution sensor.
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Transcend 800x CompactFlash View on Amazon View on B&H
If you don’t frequently use the 5FPS burst mode of the 5DS R, you might not need the absolute fastest 1066x or 1050x cards. The Transcend 800x is an excellent “Also Great” choice that provides plenty of speed for landscape, architectural, or studio work. With write speeds hovering around 60-80MB/s, it handles the 50MP RAW files well enough for methodical shooting. I find it perfect for secondary cameras or for photographers who prefer to take their time with each composition. It still supports UDMA 7, ensuring it communicates properly with the Canon hardware. The limitation is obvious when you try to shoot a long sequence; you’ll hit the buffer wall about 2-3 frames sooner than with a 1066x card. But for the price, it offers a reliable, large-capacity solution for photographers who value resolution over speed. It’s a dependable workhorse for the slower-paced professional.
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Buying Guide: How to Choose Memory Cards for the 5DS Series
Comparison Table
| Product | Best For | Rating | Price |
|---|---|---|---|
| SanDisk Extreme Pro CF | Pro Speed/Buffer | ★★★★★ | Check |
| Lexar Professional 1066x | High Value/Capacity | ★★★★☆ | Check |
| SanDisk Extreme Pro SD | Secondary Slot Backup | ★★★★☆ | Check |
| Delkin Devices Power | Rugged Reliability | ★★★★★ | Check |
| Transcend 800x CF | Studio/Architecture | ★★★★☆ | Check |
Frequently Asked Questions
Can I use UHS-II SD cards in the Canon 5DS R?
Yes, you can physically use UHS-II cards, and they will work perfectly fine. However, the Canon 5DS and 5DS R hardware only supports UHS-I speeds. The card will “throttle down” to match the camera’s slower bus speed. The only benefit to a UHS-II card in this scenario is that your file transfers from the card to your computer will be much faster if you use a UHS-II compatible card reader.
Which slot should I use as my primary?
You should always use the CompactFlash (CF) slot as your primary for RAW files. The CF slot supports UDMA 7, which allows for write speeds up to 150MB/s. The SD slot is significantly slower (limited to UHS-I). If you shoot a burst of images to the SD slot, the camera will take much longer to clear the buffer, potentially preventing you from taking more photos during that time.
How many photos can I fit on a 128GB card?
On a Canon 5DS or 5DS R, a standard 128GB card will hold approximately 1,600 to 1,800 RAW images. If you shoot in RAW+JPEG Large, that number drops to around 1,200 images. Because the file sizes are so massive, I highly recommend using at least 128GB cards for professional work, especially if you are shooting landscapes or events where you can’t easily offload files.
Is the 5DS R “Mark II” a real camera?
Currently, there is no official “Mark II” version of the 5DS or 5DS R. Canon has shifted its focus toward the mirrorless EOS R system, specifically the EOS R5, which serves as the spiritual successor to the high-resolution 5DS line. If you see a “Mark II” mentioned, it likely refers to the 5D Mark II (an older model) or speculative rumors. These card recommendations apply to the original 5DS/5DSR.
What happens if I use a slow card?
If you use a slow or “standard” SD card in the 5DS, the camera will frequently display a “Busy” message on the top LCD and in the viewfinder. You’ll be able to take a few shots, but the frame rate will drop dramatically once the internal buffer fills up. For a camera designed for high-detail work, using a slow card is like putting budget tires on a high-performance sports car.
Final Verdict
For the serious landscape or studio photographer using the Canon 5DS/R, I strongly recommend the SanDisk Extreme Pro CompactFlash as your primary card; its UDMA 7 support is vital for those 50MP files. If you’re building a kit on a budget, the Lexar 1066x offers nearly identical performance for less. Don’t forget to grab a SanDisk Extreme Pro SD card for your second slot to act as a reliable backup or overflow for your JPEGs.