This article will provide an overview of Class 10 SD cards and whether they are suitable for recording 4K video. We’ll start by explaining what a Class 10 card is and its speed rating. Then we’ll look at the data rate requirements for 4K recording and compare that to real-world Class 10 performance. While Class 10 cards can work for 4K in some cases, they are not always fast enough – so we’ll also discuss faster UHS options you may want to consider. Finally, we’ll provide tips for getting the best 4K video quality and recommendations for SD cards to use with different types of 4K-capable cameras.
What is a Class 10 SD Card?
SD cards are rated by speed classes to indicate the minimum guaranteed speeds they support. The main ratings are Speed Class 2, 4, 6, and 10. As the number increases, the minimum write speed increases. According to the SD Association, a Class 10 SD card has a minimum write speed of 10MB/s.
However, most Class 10 cards today have much faster speeds. Real-world write speeds for Class 10 cards generally range from 20-90 MB/s depending on card capacity and brand. So while 10 MB/s is the minimum for Class 10, many can write significantly faster in real usage.
The Class 10 rating itself does not give the maximum speed, only the guaranteed minimum. Cards with U1, U3, V30, or V90 ratings will indicate even faster performance capabilities.
4K Video Requirements
4K video has an extremely high resolution of 3840 x 2160 pixels, which is over 8 million pixels total. This dwarfs the resolution of 1080p video which is 1920 x 1080 pixels. The higher resolution means more detail and sharpness in the video.
4K video also has a very high bitrate. Bitrate determines how much data is used per second of video. 4K video can have bitrates exceeding 100 Mbps, compared to just 5-10 Mbps for 1080p. This higher bitrate preserves more detail and avoids compression artifacts.
According to Kingston, an hour of 4K video requires about 45GB of storage space (https://www.kingston.com/en/blog/personal-storage/choose-storage-4k). The high resolution and bitrate require fast write speeds from an SD card.
Class 10 Speeds
Class 10 SD cards have a minimum write speed of 10MB/s according to the SD Association, the organization that defines SD card speed classes. This means a Class 10 card is guaranteed to sustain transfer rates of at least 10MB/s when recording video or transferring files.
However, most modern Class 10 cards offer much faster speeds than the minimum 10MB/s. For example, popular cards like the SanDisk Extreme Pro are rated up to 90MB/s write speeds. So while the Class 10 rating ensures a baseline level of performance, it does not indicate the maximum capabilities of a card.
The 10MB/s minimum speed was sufficient for full HD 1080p video recording when Class 10 was introduced. But higher video resolutions like 4K require faster write speeds for smooth recording. So relying solely on the Class 10 rating does not guarantee a card can handle 4K video.
Real-World Performance
When testing class 10 SD cards with 4K video recording, benchmarks reveal mixed results depending on the specific camera and recording settings used. According to tests done by Camera Memory Speed, some class 10 cards can handle basic 4K recording, but may struggle with more demanding specs like high frame rates or significant compression. They found that while basic class 10 cards could record 4K video around 5-10 MB/s, transfer speeds dropped significantly below the rated 10 MB/s minimum during extended recording sessions or when using features like HDR.
Testing by Topesel confirmed class 10 cards are generally sufficient for short 4K clips. However, performance suffered when recording longer segments, with dropped frames and recording stopping on some budget-friendly class 10 options. Faster cards maintained consistent write speeds closer to the minimum 10 MB/s specification.
So while class 10 SD cards can technically handle basic 4K recording, their real-world performance is very dependent on the camera settings and length of videos being recorded. To maintain speeds and minimize issues, 4K video recording requires SD cards faster than the minimum class 10 specification.
When a Class 10 Card is Not Enough
While Class 10 cards offer decent speeds, they can still struggle with high bitrate 4K video recording. This is especially true for lower capacity cards, like 16GB or 32GB.
4K video has very large file sizes due to the high resolution and bitrates. A 16GB card may only hold 5-10 minutes of 4K footage. The constant writing of large chunks of data can overwhelm a basic Class 10 card, causing recording to stop unexpectedly.
As this Reddit user experienced, their 48MB/s Class 10 card was insufficient for recording 4K at 50fps on their Panasonic GH5 camera: “Is it possible that a Class 10, 48MB/s wouldn’t be able to handle 4k, 8bit at 50fps? According to this chart, it should be just fine..” Source
While Class 10 cards are fine for lower resolution HD video, 4K recording demands more consistently high write speeds that entry-level Class 10 cards cannot always sustain, especially at their capacity limits.
Faster Options
If you need to record 4K video at high frame rates or capture high bitrate 4K footage, a Class 10 card may not cut it. For more demanding 4K video needs, look for SD cards with higher UHS speed classes and V-ratings:
UHS Speed Classes:
– UHS Speed Class 3 (U3): Minimum 30 MB/s write speed
– UHS Speed Class 1 (U1): Minimum 10 MB/s write speed
V-Ratings:
– V30: Minimum 30 MB/s sustained write speed
– V60: Minimum 60 MB/s sustained write speed
– V90: Minimum 90 MB/s sustained write speed
Cards like the SanDisk Extreme Pro line with UHS-II, V30/V60/V90 ratings are ideal for capturing professional-level 4K footage without dropping frames or compromising quality.
The faster write speeds of these cards allow you to record high bitrate 4K video at 60fps, 120fps or higher frame rates. This makes them especially suitable for shooting 4K on high-end cameras and smartphones.
Recommendations
To reliably record 4K video, the minimum SD card specs you should look for are:
- UHS Speed Class 3 (U3) rating or higher – U3 guarantees a minimum sequential write speed of 30MB/s which is the bare minimum for stable 4K recording according to Kingston and ProGrade Digital.
- V30 video speed rating – V30 also indicates a minimum write speed of 30MB/s but is a more stringent rating focused on sustained video recording performance according to Improve Photography.
- Write speeds of at least 90MB/s – Though the minimum is 30MB/s, faster cards in the 90-95MB/s range will provide more reliable 4K recording and room to spare for high bitrate footage according to Kingston.
Cards meeting these specs from reputable brands like SanDisk, Samsung, Sony, Lexar, or Kingston are good choices.
Tips for 4K Recording
There are some things you can do to optimize your camera settings and file management for 4K video recording:
When it comes to camera settings, choose the highest possible video resolution and frame rate that your camera supports. For example, record in 4K at 30fps or 60fps if available. Higher resolution and frame rates require fast write speeds, so make sure your SD card can handle it.
Set the bitrate or quality setting to the highest available, like ALL-I compression instead of IPB on Canon cameras. Higher bitrates produce better quality but again require very fast cards to avoid issues.
Turn off automatic gain and set ISO manually. Auto ISO can cause exposure changes during recording. Set it to the lowest native ISO your camera offers.
Use a neutral picture profile or “flat” color profile. This preserves more dynamic range to allow greater flexibility in post-production.
For file management, break up long recordings into smaller segments of 5-10 minutes. This makes files easier to edit and avoids corruption or loss of huge files if something goes wrong.
Offload files from your memory card to a computer or external hard drive after each shoot. Don’t keep piling on more 4K footage to a full card to avoid performance issues or accidental deletion.
Make sure to format your card in the camera, not on your computer. The camera will optimize the card’s file system for maximum 4K recording performance.
Conclusion
In summary, while Class 10 SD cards offer decent speeds, they may not reliably handle sustained 4K video recording due to their minimum write speeds. For 4K video, UHS Speed Class 3 or Video Speed Class 30 cards are better options, as they guarantee minimum write speeds of 30MB/s. Still, real-world performance can vary between cards, so choose reputable brand models designed for 4K recording. Test your card with your camera before an important shoot. Use the fastest card your camera supports for best 4K results. Employ additional strategies like shooting shorter clips and allowing buffer clearance between takes. With the right SD card and techniques, you can successfully capture stunning 4K footage.