About SD Cards
Your video is likely being clipped if the information bunches to a hard edge at 0% or above
100% along the horizontal scale. Video clipping is undesirable when you are shooting, as detail
in the blacks and whites must be preserved if you subsequently want to perform color
correction in a controlled environment. When shooting, try to maintain your exposure so
information falls off gradually at the edges of the histogram with most forming around the
middle. This will give you more freedom later to adjust colors without whites and blacks
appearing flat and lacking in detail.
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.
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