Yeah, I totally agree with the point about reliability over just chasing raw speed numbers. Tbh, I'm still a bit of a beginner with these high-end bodies, but I've been reading up on the technical side since I'm also looking for cards. Your going to want to make sure you focus on the CFexpress Type B slot for your 4K automotive work, as the SD slot might hold you back on the higher bitrates. Here are a few things I've noticed regarding compatibility for the R5 II: * Angelbird AV Pro CFexpress B SE - This seems like a total steal for the price (usually around $180 for 512GB). It should handle most 4K modes without breaking a sweat.
* Delkin Devices POWER CFexpress Type B - These are super popular and afaik they have great heat management, which might be big if your filming cars out in the sun.
* Double check if the card is VPG-400 certified. I think the manual says you need that specific rating for some of the higher-end video features to work properly without the camera stopping. Does anyone know if the R5 II has issues with older Gen 1 cards? I'm worried about fitment or power draw issues if I buy used cards off eBay.

Building on the earlier suggestion about reliability being the priority... honestly, emma is right that safety comes first. Over the years, Ive tried many different brands for my video projects and in my experience, the peace of mind is worth more than saving a few bucks on a random sale. If youre looking for a solid alternative that hasnt been mentioned yet, you really cant go wrong with Angelbird CFexpress Type B. Just get whatever capacity fits your $300 budget from them and youll be fine. Theyre built like tanks and handle the sustained write speeds needed for high-end 4K car footage without breaking a sweat. Ive found that sticking to a company that basically specializes in cinema-grade media is the safest way to go when youre dealing with a high-end body like the R5 II. Better to be safe than sorry when youre out on a shoot, ya know?

Big if true

Love the energy in this thread! Finding the right media is basically the most stressful part of a new rig. Safety first always!

• You should definitely spend some time on the VPG-400 certification websites to understand sustained write speeds properly.
• Another fantastic resource is looking through the deep-dive tests on sites like Alik Griffin or Camnostic... they do amazing work breaking down real-world buffer clears. This whole topic reminds me of my cousin who was shooting a massive classic car rally a few years back. He spent a fortune on his setup but didnt verify his media properly for the specific codec he was using. Right as a rare Ferrari GTO was pulling out, his camera just threw a write error and locked up completely! He was absolutely devastated... he tried every recovery software under the sun but that file was just toast. It just goes to show how even a small oversight can ruin a whole trip!

Sandisk Extreme Pro's worked great for my 4K car videos. Got two 128GB cards for ~$60.

Congrats on the R5 II! For 4K, be careful with sustained write speeds. V60 cards *might* be okay, but V90 are safer. I'd suggest multiple smaller cards (128GB) over one huge one; less data loss if a card fails. Check the camera's manual for minimum specs, and maybe consult a pro videographer before committing. SanDisk Extreme Pro is a decent start.

Congrats on the R5 II! Forget chasing max speeds. Prioritize RELIABILITY. I've lost footage to fast but flaky cards. For 4K, stick with reputable brands and look for cards with robust error correction. Sandisk Extreme Pro has been decent for me over the years. Test thoroughly before any critical shoot! Consider multiple smaller cards for redundancy; losing everything on one card is a nightmare.

Congrats on the R5 II! For cost-effective 4K, skip the fastest cards. I've found that Lexar Professional 2000x cards offer a great speed/price balance. A couple of 256GB cards should do you. Over the years, I've never had issues with them, and you can probably snag two for under $200 total. Focus on UHS-II U3 rating; that's the sweet spot for reliable 4K.

Over the years, ProGrade Cobalt cards have been reliable. I'd grab two 128GB for ~$250.

Congrats on the R5 II! Lexar Professional cards have been consistently reliable for me over 5 years. Check user reviews; some brands trade speed for longevity in that price range. Be careful!

DIY'er here: Lexar Pro. Format in-camera only! I'd suggest smaller cards; avoid single point failure.