Batteries & Storage
CFexpress Card Buying Guide for Filmmaking
The short answer
How to choose a CFexpress card by type, capacity, and write speed, with real brands to compare for high-bitrate video.
What's covered7
A CFexpress card is the fast storage most modern mirrorless and cinema cameras need for high-bitrate 4K and higher video, since older SD cards often can't sustain the write speed those codecs require without dropped frames. Picking the right type and capacity keeps you from stalling mid-shot.
Type A vs Type B
Check your camera's manual before buying, since Type A and Type B cards are physically different sizes and are not interchangeable. Type A cards (used mainly by Sony) are smaller and generally have lower maximum write speeds than Type B cards, which most other camera brands use, including cinema cameras from RED and higher-end Canon and Nikon bodies. Buying the wrong type simply won't fit your camera's card slot.
Capacity and shoot length
A 128GB card holds roughly an hour of high-bitrate 4K footage, though the exact runtime depends on your camera's codec and bitrate settings. A 256GB or 512GB card stretches that to a half or full day of shooting without needing to swap cards mid-scene. Buying two or three mid-capacity cards instead of one large one also gives you a backup if a single card fails.
Grab the free filmmaking gear starter checklist to see how storage capacity fits your typical shoot length.
Real brands to compare
SanDisk makes CFexpress Type B cards across a wide capacity range, widely supported across most cinema and mirrorless cameras that use the format.
ProGrade Digital builds CFexpress cards aimed at sustained high-bitrate recording, popular for cinema camera work with demanding codecs.
Sony makes its own CFexpress Type A cards, which matters if you're shooting on a Sony body that requires that specific format.
Write speed and your codec
Check your camera's minimum required write speed for the codec and resolution you shoot before buying a card. A card that meets the minimum for 4K may not keep up with a higher-resolution or higher-bitrate mode on the same camera. When in doubt, buy a faster-rated card than the minimum, since dropped frames mid-take can ruin an otherwise good shot. Pair your card choice with our CFexpress card reader guide for fast offload, and see the v mount battery hub for the rest of a power and storage kit.
Card longevity and how many you need
CFexpress cards, like any storage media, have a limited number of write cycles before performance can degrade, though for most working shooters normal use over several years of regular shoots isn't likely to be the limiting factor. What matters more day to day is simply owning enough cards that a single card failure or a full card mid-shoot doesn't stop production. Two or three mid-capacity cards in rotation give you a buffer that one large card doesn't.
Common mistakes buying CFexpress cards
The most common mistake is buying the cheapest card that fits the physical slot without checking its sustained write speed rating, then discovering it drops frames during longer takes even though it worked fine for short clips. Sustained write speed, not just the headline "up to" speed on the packaging, is what matters for continuous recording.
A second mistake is buying only one card at full capacity instead of two or three smaller ones. If that single card fails or gets corrupted, you lose an entire day's footage at once. Splitting capacity across multiple cards limits how much a single failure can cost you.
A third mistake is formatting a card in a computer instead of in the camera itself. Cameras often want their own file system structure on the card, and formatting elsewhere can cause compatibility issues or slower performance. Format new cards in the camera you'll actually use them in.
A worked example
A solo shooter filming a full day of high-bitrate 4K interviews might carry three 256GB cards instead of one 512GB or 1TB card, rotating them through the day and backing up footage to a laptop or drive between cards. That way, a single card issue costs at most a third of the day's footage instead of all of it, and offloading happens in smaller, more manageable chunks throughout the day rather than one large transfer at the end.