Late to the party but honestly if youre looking at reliability above all else, you gotta check out the Delkin Devices BLACK CFexpress Type B 512GB. Their replacement guarantee is insane, basically if it breaks they swap it in 48 hours. I also really like the Angelbird AV PRO CFexpress B MK2 1TB for long 8K sessions because the sustained speeds are super consistent and they dont get as hot as some others. Tbh the heat management on these newer cards is wild. It reminds me of back when I first started shooting video on a 5D and tried to edit it on my old MacBook Pro. That thing would get so hot you could practically fry an egg on the trackpad... I think I actually singed my leg once during a summer edit session. Anyway, both those cards are solid choices for the R5 II, but yeah.

@Reply #4 - good point! Tbh I'm pretty new to shooting 8K so I've been taking a very conservative approach to picking my cards. I really focus on that VPG-400 rating because I dont want to risk any dropped frames or corrupted files during a long shoot. I decided to look at the Sony TOUGH G Series CFexpress Type B 512GB since the build quality is supposedly superior for durability. Its nice knowing the card is physically reinforced if you're worried about accidental damage. Another brand that seems very reliable for high-bitrate video is the Wise Advanced CFexpress Type B PRO 640GB. They specialize in cinema storage, so the sustained write speeds are very consistent which is exactly what the R5 Mark II needs for that 8K RAW footage. The OWC Atlas Ultra CFexpress Type B 1TB is also a great alternative if you want a lot of space without sacrificing speed. Basically, you just have to look past the peak speeds on the box and find the "minimum sustained" numbers. Its easy to get caught up in the marketing, but for a high-res camera like this, reliability and thermal stability are way more important than just having the highest possible burst read speed... it just makes sense to be safe.

For the R5 Mark II, you'll want fast CFexpress Type B cards for the best performance. I'd recommend the SanDisk Extreme Pro CFexpress (128GB or larger) or the Lexar Professional CFexpress Type B. These handle the high bitrate video recording and burst shooting without issues. If budget's a concern, the SanDisk cards often go on sale. Make sure whatever you get has read speeds of at least 1400MB/s and write speeds around 1000MB/s to avoid any bottlenecks with 8K recording.

For the R5 Mark II, you've got dual card slots - CFexpress Type B in slot 1 and UHS-II SD/SDHC/SDXC cards in slot 2. If you're serious about photography or video, I'd strongly recommend getting a good CFexpress Type B card for slot 1. For the best performance we recommend recording RAW to slot 1 (CFexpress) and JPEG to slot 2 (UHS-II).

For video work, especially if you plan on shooting 8K RAW which requires approximately 325 MB/s sustained write speed, you'll want a CFexpress Type B card that is VPG 400 certified. This guarantees the performance you need for the most demanding recording modes.

If you're planning to shoot a lot of video, especially 8K or high frame rate 4K, don't skimp on the cards. The Canon specs recommend minimum sustained write speeds of 800MB/s for 8K RAW, but I'd go higher for safety margin. Currently using ProGrade Digital Cobalt cards and they've been rock solid. The 325GB model gives you decent record time without breaking the bank completely.