Recording RAW with Budget SD Cards 4K DCI 60fps with Slow SD Cards on BMPCC4K Braw Blackmagic Pocket Cinema camera 4K Guide
- Caillou Wang 王靖凱
- Jan 16
- 3 min read
Optimizing Blackmagic RAW Recording with Slow SD Cards: A Guide
Today, I want to share some insights on using slow SD cards to shoot Blackmagic RAW footage. You may wonder, why use an SD card instead of an SSD? Well, I prefer keeping my setup simple, without a bulky camera cage or USB cables hanging around. The goal is to maintain the portability of my Pocket Cinema Camera.
BMPCC4K Braw SD Card Guide
Why Choose SD Cards?
When working with Blackmagic cameras, you can select between CFast and SD cards. While CFast cards are faster, SD cards are significantly more affordable. On Blackmagic Design’s website, they provide data on different camera bit rates—like the URSA Mini Pro 4.6K, which shoots at 30 frames per second with a data rate of 46 megabits per second. However, I’m working with the Pocket Cinema Camera 4K, so I need to consider its specific data requirements.
Calculating the Required Data Rate
To calculate the data rate, we start with the URSA Mini Pro’s 46 megabit per second benchmark. This represents the pixels output every second. However, shooting 4K DCI at 60 frames per second demands more bandwidth. You’ll need an SD card that can handle at least 68 megabits per second to record Blackmagic RAW 12:1 at that resolution and frame rate.
Testing SD Cards for Blackmagic RAW
I’ve tested several SD cards, including the Sony 64GB, SanDisk Extreme, and SanDisk Extreme Pro, to see if they can handle the data rate required for 4K DCI 60 frames per second at 12:1 compression. Here’s what I found:
Sony 64GB: It can write at 64 megabits per second, which is slightly lower than the 68 megabits per second we need. With this speed, you can record about 25 seconds of Blackmagic RAW 12:1 before the card runs out of buffer.
SanDisk Extreme: This card writes at 60 megabits per second, which is even lower. With this, you can only record about 10 seconds before encountering issues.
SanDisk Extreme Pro: This card performs better, writing around 78 megabits per second. It’s fast enough to record Blackmagic RAW 12:1 until the card is full without dropping frames.
Choosing the Right SD Card
Blackmagic Design provides a recommended list of SD cards on their website, but many of them are expensive. If you’re only recording Blackmagic RAW at 12:1 compression, you can explore cheaper alternatives. The key is to ensure your SD card can maintain a stable write speed above 68 megabits per second for smooth 4K DCI 60fps recording.
Useful Resource: Camera Memory Speed
I’ve come across a fantastic website called Camera Memory Speed that provides real-world tests of memory cards. Their results are highly accurate, and you can use the site to find affordable SD cards that still meet the necessary requirements for Blackmagic RAW recording.
Final Thoughts
In conclusion, if you’re using slower SD cards for Blackmagic RAW 12:1, make sure they can handle at least 68 megabits per second to shoot 4K DCI at 60fps without issues. Some cards, like the SanDisk Extreme Pro, offer a budget-friendly solution while still delivering reliable performance.
I’ll leave a link to the Camera Memory Speed website in the description—definitely check it out before buying your next SD card. Remember, shooting in 4K DCI 60fps with Blackmagic RAW 12:1 compression requires the right tools, and a high-speed SD card is key to ensuring smooth and reliable footage.
Thank you for watching, and I hope this guide helps you make the best choice for your Blackmagic camera setup!
BMPCC4K Braw SD Card Guide
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