Recommended SD Cards for External Recorder

[Jeremy Gadd]

I've just bought the Blackmagic Design Video Assist monitor and recorder. Having done a couple of tests it seems that I need to buy faster SD cards for recording onto it. Using what I have at the moment (SanDisk Ultra 64GB SDXC UHS-I 80MB/S Memory Card Class 10) I found that recording to ProRes 422 Proxy produced a file at 76 Mbps bit rate. ProRes 422 LT came out at 170Mbps. A 41 second file was 750MB LT, whereas the Proxy version was about 1/2 the size at 380MB.

As this will mostly be a back up file to the SD card in the camera, I would like to keep file sizes down but get the best resolution possible.

I did notice that there was issues with playback, hence the need to get faster cards. I tested by panning around the room at a 'normal' speed. The lower quality Proxy file played back in my editing software without glitches and seemed smooth, but the LT file started to stutter after about 3 seconds. It was unusable.

I don't really understand card speeds but have read that at least 95MB/s is recommended. I have also seen that SanDisk do one that does 300MB/s, but sells for over £100 for 64GB card!!

Can someone please advise me what I need to buy. many thanks

[Colin McDonald]

Blackmagic have a list of recommended cards on p 29 on the user manual (June 30 2017 update). It's in table format and easier to read than the text only version below:

About SD Cards

Choosing a Fast SD Card

It’s important to use high speed UHS-II SD cards for Ultra HD and HD recording, or UHS-1 cards
for HD recording. These cards are rated for fast data speeds and support larger storage sizes.

For Ultra HD recording on Blackmagic Video Assist 4K, you will need to use the fastest UHS-II
cards available. We have included a table below that shows the latest compatible SD cards for
recording Ultra HD, HD and SD video. It’s worth regularly checking the latest version of this
manual for more up to date information and can always be downloaded from the Blackmagic
Design website at www.blackmagicdesign.com/support

The following table contains SD cards we have tested and are able to record video up to a
given maximum format on Blackmagic Video Assist 4K.

Compatible SD Cards

Maximum Supported Format
Manufacturer / Model
Size

Ultra HD 2160p30 inc MXF
Transcend SDXC UHS II 180MB/s
64GB
Ultra HD 2160p30 inc MXF
Lexar SDXC UHSII 2000x 300MB/s
64GB
Ultra HD 2160p30 inc MXF
Lexar SDHC UHSII 2000x 300MB/s
32GB
Ultra HD 2160p30 inc MXF
Toshiba Exceria Pro SDXC UHSII
64GB
Ultra HD 2160p30
Delkin Devices SD SDHC UHSII 250MB/s
32GB
Ultra HD 2160p30
SanDisk Extreme Pro SDXC UHSII 280MB/s
64GB
HD 1080p60 inc MXF
SanDisk Extreme Pro UHS I 95MB/s
64GB
HD 1080p60
Lexar SDHC UHS II 1000x 150MB/s
32GB
HD 1080p60
Lexar SDXC UHS II 1000x 150MB/s
64GB
HD 1080p60
Lexar SDXC UHS II 1000x 150MB/s
128GB
HD 1080p60
Lexar SDXC UHS II 1000x 150MB/s
256GB
HD 1080p30 inc MXF
Lexar SDHC UHS I 633x 95MB/s
32GB
HD 1080p30 inc MXF
Lexar SDXC UHS I 633x 95MB/s
64GB

Most UHS-I and UHS-II SD cards should be fast enough to record compressed HD video up to
60 frames per second, however it’s worth testing your card’s record speed to be sure. You can
do this using Blackmagic Disk Speed Test software which can be downloaded from the
Blackmagic Design support center. For information on using Disk Speed Test, refer to ‘checking
disk speed’ in this section of the manual.

There's also a list of recommended cards on the FAQ for the Video Assist and the Video Assist 4K

I'm using cards from this series and they seem to work OK in a Video Assist 4K, but I'm doing mostly 1080 HD not 4K on it.

PS: Check you have the latest software - it should be v2.5

[Jeremy Gadd]

Thanks for that, I can't believe I missed that in the manual.