Best Memory Cards for Canon EOS 5DS & 5DS R Mark II
Owning a Canon EOS 5DS or 5DS R means you’re handling a 50.6-megapixel beast that produces massive files. I’ve found that nothing kills a shoot faster than seeing the “Busy” signal while the buffer struggles to clear those 60MB RAW files. Because these cameras use older UDMA 7 CF and UHS-I SD technology, choosing the right card is about maximizing those specific limits. My top pick, the SanDisk Extreme Pro CF, remains the gold standard for keeping these high-resolution sensors humming without a hitch.
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
The Canon 5DS and 5DS R are designed around the UDMA 7 interface, and the SanDisk Extreme Pro CF card is the absolute best way to utilize it. With read speeds up to 160MB/s and write speeds up to 150MB/s, this card handles the massive 50.6MP data throughput better than any other. In my experience, when shooting landscape panoramas where I’m firing off several RAW frames in succession, the buffer clears noticeably faster compared to using the SD slot. It features the Video Performance Guarantee (VPG-65), ensuring that even if you’re shooting 1080p video, the data stream never drops. While CompactFlash is an older format, SanDisk’s build quality remains top-tier—these cards are heat, shock, and vibration resistant. The only real downside is that CF cards are physically bulkier and require more care when inserting to avoid bending camera pins, but for professional-grade reliability, this is the card I trust most.
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Lexar Professional 1066x CompactFlash View on Amazon View on B&H
If you need high-capacity storage for a long studio day but don’t want to pay the “SanDisk tax,” the Lexar Professional 1066x is a fantastic alternative. It offers identical peak read speeds of 160MB/s, which makes offloading those massive 5DS file folders a breeze once you get back to your workstation. I’ve used Lexar cards for years in my 5D-series bodies and they provide very consistent performance. This card is particularly great for portrait photographers who might take hundreds of shots in a session but don’t necessarily need the extreme “bulletproof” ruggedness of the SanDisk. It fully supports UDMA 7, meaning it won’t be the bottleneck in your 5DS workflow. Just keep in mind that while Lexar has improved their quality control recently, I still recommend formatting the card in-camera every time you clear it to ensure the file system remains snappy and error-free.
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SanDisk Extreme Pro SDXC UHS-I View on Amazon View on B&H
The SD slot in the Canon 5DS is limited to UHS-I speeds, meaning you don’t need to spend extra on expensive UHS-II cards—the camera simply can’t use the extra pins. The SanDisk Extreme Pro SDXC UHS-I is the ideal choice here. While its read speeds can reach 200MB/s (with a proprietary reader), it writes at roughly 90MB/s, which is essentially the maximum the 5DS can handle. I often use this as my “overflow” card or as a dedicated JPEG backup slot. It’s incredibly affordable, allowing you to buy multiple 128GB or 256GB cards without breaking the bank. The main limitation is that if you set the camera to “Rec To Multiple” (writing RAW to both cards), the slower SD write speed will bottleneck the faster CF card. However, for casual shooting or as a fail-safe backup, it’s a reliable workhorse that has never failed me in the field.
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Delkin Devices 128GB Black CF View on Amazon View on B&H
For photographers taking their 5DS R into harsh environments—think dusty deserts or freezing alpine peaks—the Delkin Black series is the pinnacle of CF card technology. These aren’t just fast; they are built with a molded design that is significantly more durable than standard cards. They are rated to withstand up to 80 pounds of force and are tested for extreme temperature ranges. In terms of performance, it hits the UDMA 7 limit with ease, providing a rock-solid 150MB/s write speed. What truly makes this a “premium” choice is the Delkin “Lifetime Warranty with 48-hour replacement.” If your card fails, they will ship you a new one before they even receive your broken one. You’re paying for the piece of mind that your 50MP files are as safe as possible. It’s an investment, but for a professional assignment, it’s the ultimate insurance policy for your data.
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Transcend 800x CompactFlash View on Amazon View on B&H
The Transcend 800x is a reliable middle-ground card that often flies under the radar. While it’s slightly slower than the 1066x cards (offering 120MB/s read and 60MB/s write), it is incredibly stable. For a 5DS user who primarily shoots landscapes from a tripod and isn’t rushing the buffer, the 60MB/s write speed is perfectly adequate. I’ve found these cards to be particularly long-lasting; the built-in Error Correcting Code (ECC) does a great job of preventing data corruption over long-term use. If you’re looking to stock up on several 64GB cards for a long trip where you won’t have access to a computer for offloading, these provide a great balance of cost and reliability. They are UDMA 7 compliant and multi-platform compatible. It’s not the speed king, but it’s a dependable “old faithful” that won’t let you down when you’re capturing that perfect golden hour shot.
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Buying Guide: How to Choose Memory Cards
Comparison Table
| Product | Best For | Rating | Price |
|---|---|---|---|
| SanDisk Extreme Pro CF | Pro Performance | ★★★★★ | Check |
| Lexar Professional 1066x | Value CF | ★★★★☆ | Check |
| SanDisk Extreme Pro SD | Budget/Backup | ★★★★☆ | Check |
| Delkin Black CF | Durability | ★★★★★ | Check |
| Transcend 800x CF | Slow & Steady | ★★★★☆ | Check |
Frequently Asked Questions
Can I use UHS-II SD cards in the Canon 5DS?
Yes, you can use UHS-II cards, but you won’t get any speed benefit while they are in the camera. The 5DS hardware is limited to UHS-I speeds. The only advantage of a UHS-II card would be faster transfer speeds when moving photos from the card to your computer using a UHS-II card reader. For in-camera use, a high-quality UHS-I card like the SanDisk Extreme Pro is much more cost-effective.
What is the maximum card capacity the 5DS supports?
The Canon 5DS and 5DS R support the SDXC and CF standards, meaning they can theoretically handle cards up to 2TB. In practical terms, most photographers use 128GB or 256GB cards. I find that 128GB is the safest balance; it holds plenty of 50MP images but doesn’t put “all your eggs in one basket” if a card were to be lost or damaged during a shoot.
Why does my camera slow down when I use two cards at once?
If you set your 5DS to “Record to Multiple” (writing the same file to both the CF and SD slots), the camera must wait for the slowest card to finish writing. Since the SD slot is inherently slower than the CF slot, your fast CF card is throttled to match the SD card’s speed. To maintain maximum performance, shoot RAW to the CF card and JPEG to the SD card, or use the slots sequentially.
Is CompactFlash (CF) better than SD for the 5DS?
For this specific camera, yes. The CF slot supports UDMA 7, which offers a higher theoretical and practical write speed than the UHS-I SD slot. Because the 5DS produces such large files, that extra speed is crucial for clearing the buffer during continuous shooting. The CF pins are also more robust for professional use, though you must be careful not to bend them during insertion.
How many RAW photos fit on a 64GB card?
On a 50.6MP Canon 5DS, a single uncompressed RAW file is roughly 60-70MB. A 64GB card will typically hold between 800 and 900 images. If you shoot RAW + JPEG, that number drops to around 650 images. For a full day of professional shooting, I highly recommend carrying at least two 128GB cards to ensure you don’t run out of space during a critical moment.
Final Verdict
For the Canon 5DS and 5DS R, your primary investment should always be a high-quality CF card. The SanDisk Extreme Pro CF is my definitive recommendation for those who need to maximize the 50.6MP sensor’s potential without buffer lag. If you are a studio photographer on a budget, the Lexar 1066x offers nearly identical speeds for less. Always keep a fast SanDisk SD card in the second slot for peace of mind and instant backup.
