I would follow the camera maker’s approved card requirements for the exact recording mode, then use the speed class to understand the sustained-write requirement. Capacity and a large advertised read speed answer different questions. A fast reader does not make an unsuitable recording card safe for a demanding mode.
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Our recommendation
I favour an explicitly supported card with sufficient capacity over the cheapest card with a reassuring logo. Pay for V60 or V90 when the mode requires it or the documented workflow benefits, rather than assuming more expensive always means necessary.
Distinguish sustained write from peak read
The SD Association maps Video Speed Classes V30, V60 and V90 to minimum sequential write classes of 30, 60 and 90 MB/s under the relevant system conditions. The device must support the required protocol and mode. A large “up to” read-speed number on packaging is not the same metric.
Check the exact card model, capacity and camera firmware against the manufacturer’s requirements. Some recording modes demand a particular class or card type beyond a simple average-bitrate calculation. Keep the camera’s requirement as the purchase gate rather than using arithmetic to overrule it.
Budget the real recording
Convert megabits to megabytes by dividing by eight, then include the mode’s behaviour and the maker’s margin or approval requirements. Plan capacity separately from speed. A card may be fast enough but too small for the session, or large enough but unsuitable for the mode.
Test the intended mode for a representative duration with non-critical material, then verify the files and playback. Buy from a reliable source and use the camera’s documented preparation process. Preserve verified copies before clearing or reformatting a card.
A bitrate calculation with a limit
A hypothetical 200 Mbit/s payload is 25 MB/s. That explains the scale of the data rate, but it does not prove that any V30 card is approved for that camera mode. Check the mode’s official requirement and the exact card, then run the practical recording test.
Before you act
- Check the exact camera mode and approved card requirements.
- Separate write class, read speed and capacity.
- Verify a representative recording before important work.
Use the Recording storage calculator to apply the guide to your own setup.
Keep exploring
- Plan recording storage from actual bitrates
- Verify a media copy with a hash before clearing the recording card
Sources and research notes
Research checked on 21 October 2026. Product specifications are manufacturer statements; examples and buying judgements are our analysis. No hands-on product test is implied.
Build on what you just learned
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