Cameras Ranked
What a Memory Card's Speed Marks Actually Guarantee
After this page you will be able to open your own camera's manual, find the row for the exact video mode you shoot, and know which two card specifications — the capacity and bus type, and the class mark — that row is asking you to buy. You will also know the two places where buying a higher mark does not help, and the one place where it fails outright.
Buy to the fastest video mode you genuinely shoot, not to the camera's headline resolution and not to the number printed on the front of the box. Your camera maker publishes a table that maps each recording format to a required card mark. That table is the answer. Everything below is how to read it, and why the number on the package is a different kind of number from the number in the table.
Every figure on this page is taken from the SD Association, the CompactFlash Association, a camera manufacturer's own manual or support page, or SanDisk's published support documentation, each cited with the page it came from and the date it was read (2026-09-22). The per-class minimum write speeds in MB/s come from SanDisk's support article, because the SD Association's own Speed Class page states the convention without printing the figures. Nothing here is ranked, scored, or called best.
The four-step version
- Open your camera's manual to its card section. Sony's help guide calls the page "Memory cards that can be used". Canon's EOS R5 manual uses "Cards That Can Record Movies" and points from there to "Card performance requirements (Movie recording)" in its Reference chapter. Fujifilm publishes a per-camera compatibility page.
- Find the row for your exact recording format and frame rate — XAVC S-I 4K, or 360 Mbps, or the S&Q row, or the 10-bit column rather than the 8-bit one — not the row for "4K" in general.
- Read three things off that row: the class mark (Class 10, U3, V30, V60, V90, VPG200, VPG400), the card type (SDHC/SDXC, CFexpress Type A, CFexpress Type B), and, where the row names one, the capacity tier. SDHC and SDXC are capacity tiers, not speed tiers: SanDisk gives SDHC as 4GB–32GB and SDXC as 64GB–2TB. When a row names SDXC specifically rather than SDHC/SDXC, a 32 GB SDHC card does not satisfy it even if it carries the right class mark. If the row carries a footnote marker, read the footnote too: it can raise the requirement for one particular frame-rate or bit-rate setting inside that row.
- Buy a card carrying that mark or higher, in that type. Higher is safe for SD class marks within one system. It is not safe for VPG, and it is not safe across SD systems — the two exceptions are in the sections below. A higher mark in the wrong type is never a substitute.
Two different kinds of number share the same package
A card marked "up to 280MB/s" and "V60" is telling you two unrelated things. SanDisk's own support article draws the line: a rated speed is the card's maximum, roughly what you would expect in typical use, while a Speed Class is a minimum based on a worst-case-scenario test. The maximum matters when you are offloading a shoot, and — inferred from the same distinction, since clearing a burst buffer is a short burst write rather than a sustained one — when you are emptying a camera's buffer. The minimum is the one that decides whether a recording runs to the end of the take. Camera manuals are written in minimums, which is why they name class marks and never quote the headline figure.
Four marking systems, and why you cannot swap between them
The SD Association defines four separate systems: Speed Class, UHS Speed Class, Video Speed Class and SD Express Speed Class. The number after the letter is the minimum writing speed. They overlap numerically — U3 and V30 are both 30 MB/s minimums, which is why Fujifilm can name either one for the same mode (inferred, from Fujifilm's wording placed beside the SD Association's class list). Do not generalise that into swapping systems on your own. The SD Association warns that a mismatched combination — its own examples are a Class 10 host with a U1 card, and a U1 host with a V10 card — will not deliver the expected write speed, in its words even though those are indicated to the same 10MB/sec write speed. Match the system your camera names, not just the number. Canon's own SD table uses all three of "SD Speed Class 10", "UHS Speed Class 3" and "Video Speed Class 60" in different rows, so this is not hypothetical.
| Mark | System | Minimum write (MB/s) | Bus interface it may be applied to |
|---|---|---|---|
| Class 2 | Speed Class | 2 | Not stated on the SD Association page read |
| Class 4 | Speed Class | 4 | Not stated on the SD Association page read |
| Class 6 | Speed Class | 6 | Not stated on the SD Association page read |
| Class 10 | Speed Class | 10 | High Speed mode or faster |
| U1 | UHS Speed Class | 10 | SDR50/DDR50 or faster (UHS-I, UHS-II, UHS-III) |
| U3 | UHS Speed Class | 30 | SDR50/DDR50 or faster (UHS-I, UHS-II, UHS-III) |
| V6 | Video Speed Class | 6 | High Speed and UHS families |
| V10 | Video Speed Class | 10 | High Speed and UHS families |
| V30 | Video Speed Class | 30 | UHS family |
| V60 | Video Speed Class | 60 | UHS-II mode or faster (UHS-II / UHS-III) |
| V90 | Video Speed Class | 90 | UHS-II mode or faster (UHS-II / UHS-III) |
| E150 / E300 / E450 / E600 | SD Express Speed Class | Number is the minimum write speed in MB/s (calculated) | SD Express mode |
One consequence is worth stating plainly. V60 and V90 may only be applied to UHS-II and UHS-III cards, and UHS-II onward moves data over a second row of pins. So a genuine V60 or V90 SD card always has two rows of contacts on the back. If a card shows one row and a V90 logo, something is wrong with the card, not with your camera.
The bus is a separate question from the class
| Bus mode | Maximum speed | Pin rows |
|---|---|---|
| Default Speed | 12.5 MB/s | One |
| High Speed | 25 MB/s | One |
| UHS-I SDR50 / DDR50 | 50 MB/s | One |
| UHS-I SDR104 | 104 MB/s | One |
| UHS-II, full duplex | 156 MB/s | Two |
| UHS-II, half duplex | 312 MB/s | Two |
| UHS-III, full duplex | 312 MB/s and 624 MB/s | Two |
| SD Express, PCIe Gen.3 x1 | 985 MB/s | Two |
| SD Express, PCIe Gen.4 x1 or Gen.3 x2 | 1970 MB/s | Two |
| SD Express, PCIe Gen.4 x2 | 3940 MB/s | Two |
Here is the rule that saves money, stated only as far as its source states it. SanDisk says that a UHS-II card can be used in UHS-I and non-UHS hosts, and that the slower UHS-I or SD speed is what gets used. Putting a 312 MB/s-capable UHS-II card into a UHS-I slot does not give you UHS-II throughput; it gives you a UHS-I card that cost more. The reason to buy UHS-II for a UHS-I body is if you also want the transfer speed in a UHS-II reader, which is a workflow decision, not a recording one. That statement covers UHS-II cards. It does not cover SD Express, and neither SD Association page read here states what an SD Express card does in a UHS-II slot — so do not assume a two-row SD Express card gives you UHS-II speed in a UHS-II camera. Check the card maker's own compatibility statement for that specific card before buying one for a UHS-II body.
Your manual speaks Mbps, the card speaks MB/s — and the arithmetic never gives the answer
Camera makers quote video bitrate in megabits per second. Cards are marked in megabytes per second. Divide by eight. Then notice that in every single published case below, the maker demands more than the arithmetic asks for, and by wildly different margins.
| Mode (source) | Stated bitrate | ÷8 = average MB/s | Class the maker requires (its MB/s floor) | Headroom over the arithmetic |
|---|---|---|---|---|
| Sony a7 IV, XAVC S 4K, normal | 200 Mbps | 25 | U3 / V30 (30) | 1.2× |
| Sony a7 IV, XAVC S 4K, S&Q Motion | 200 Mbps | 25 | V60 (60) | 2.4× |
| Sony a7 IV, XAVC S-I 4K | 600 Mbps | 75 | V90 (90) | 1.2× |
| Sony a7 IV, XAVC S-I HD | 222 Mbps | 27.75 | V90 (90) | 3.2× |
| Sony a7 IV, any mode at 60 Mbps or lower | 60 Mbps | 7.5 | Class 10 (10) | 1.3× |
| Fujifilm X-T5 movie | 360 Mbps | 45 | V60 (60) | 1.3× |
| Fujifilm X-T5 movie | 200 Mbps | 25 | U3 / V30 (30) | 1.2× |
| Fujifilm X-T5 movie | 100 Mbps | 12.5 | U3 / V30 (30) | 2.4× |
Read the right-hand column before you trust the middle one. The required headroom ranges from 1.2× to 3.2×, and nothing in the stated bitrate predicts which you will get. The worst case is Sony's XAVC S-I HD: 222 Mbps divides to 27.75 MB/s, which a V30 card clears on paper, yet Sony requires V90 — a 90 MB/s floor, 3.2 times the arithmetic. A reader who bought from the division alone would buy a V30 card for a mode needing V90. This page cannot source why any particular margin is what it is; the makers publish the requirement, not the reasoning. Treat ÷8 as a sanity floor that rules cards out, never as a specification that rules one in. The manufacturer's table is the authority. The calculator is not.
Three real manufacturer tables, side by side
| Mode | Bitrate | SD requirement | CFexpress Type A requirement |
|---|---|---|---|
| XAVC HS 4K, normal recording | 200 Mbps | SDHC/SDXC, U3 or V30 or better | CFexpress Type A |
| XAVC S 4K, normal recording | 200 Mbps | SDHC/SDXC, U3 or V30 or better | CFexpress Type A |
| XAVC S HD, normal recording | 100 Mbps | SDHC/SDXC, U3 or V30 or better | CFexpress Type A |
| Any mode at 60 Mbps or lower | ≤60 Mbps | SDHC/SDXC Class 10 also permitted | CFexpress Type A |
| XAVC S-I 4K | 600 Mbps | SDXC V90 or better | VPG200 or higher |
| XAVC S-I HD | 222 Mbps | SDXC V90 or better | VPG200 or higher |
| XAVC HS 4K / XAVC S 4K, S&Q Motion | 200 Mbps | SDXC V60 or better | VPG200 or higher |
| XAVC S HD, S&Q Motion *1 | 100 Mbps | SDHC/SDXC, U3 or V30 or better *1 | CFexpress Type A |
| XAVC S-I 4K, S&Q Motion *2 | 600 Mbps | SDXC V90 or better *2 | VPG200 or higher |
| XAVC S-I HD, S&Q Motion | 222 Mbps | SDXC V90 or better | VPG200 or higher |
The one genuinely counter-intuitive row: on the a7 IV, XAVC S 4K at 200 Mbps takes a U3/V30 card in normal recording but requires V60 or better in S&Q Motion. Same format, same stated bitrate, faster card. Only the manufacturer's table shows this — and the S&Q section does not raise every row, so read the row rather than the section heading. Then read the footnote marker on the row, because Sony hangs two further requirements off asterisks. Footnote *1, on XAVC S HD at 100 Mbps in S&Q: when Rec Frame Rate is 30p/25p/24p, Frame Rate is 120fps/100fps and the recordable bit rate is 50 Mbps, Sony requires an SDXC card of V60 or higher, or a CFexpress Type A card of VPG200 or higher. So the U3/V30 cell does not cover 120fps slow motion. Footnote *2, on XAVC S-I 4K in S&Q: when Rec Frame Rate is 30p/25p/24p and Frame Rate is 60fps/50fps, Sony requires a CFexpress Type A card of VPG200 or higher and names no SD card at all, so the V90 cell does not apply in that configuration. The cell is the general case; the footnote may be the mode you actually shoot.
| Movie recording size | Compression | SD card, 8-bit | SD card, 10-bit |
|---|---|---|---|
| 8K RAW | RAW / RAW (Light) | — | — |
| 8K | ALL-I | — | — |
| 8K | IPB | Video Speed Class 60 or higher | Video Speed Class 90 or higher |
| 8K | IPB (Light) | UHS Speed Class 3 or higher | Video Speed Class 60 or higher |
| 4K 119.88 / 100.00 fps | ALL-I | — | — |
| 4K 59.94 / 50.00 fps | ALL-I | — | — |
| 4K 59.94 / 50.00 fps | IPB | Video Speed Class 30 or higher | Video Speed Class 60 or higher |
| 4K 59.94 / 50.00 fps | IPB (Light) | UHS Speed Class 3 or higher | UHS Speed Class 3 or higher |
| 4K, other than above | ALL-I | Video Speed Class 60 or higher | Video Speed Class 60 or higher |
| 4K, other than above | IPB | UHS Speed Class 3 or higher | UHS Speed Class 3 or higher |
| Full HD 59.94 / 50.00 fps | IPB | SD Speed Class 10 or higher | UHS Speed Class 3 or higher |
Canon's table adds a dimension the other two do not. The same recording size can demand a different class depending on bit depth: 8K IPB asks for V60 at 8-bit and V90 at 10-bit, and Full HD 59.94 fps IPB moves from Class 10 to U3 on the same change. If you switch a camera to 10-bit for grading, you may have changed your card requirement without changing anything you would call a "mode". Fujifilm's X-T5 page draws its lines differently again: 360 Mbps needs V60 or better, while 100 or 200 Mbps movies need UHS Speed Class 3 or V30 or better, and Fujifilm separately recommends a UHS-II card for high-speed burst stills. Set the three makers next to each other and the point lands — Sony's 200 Mbps slow-motion row demands V60 while Fujifilm's 200 Mbps row accepts V30. The number is the same; the requirement is not. Read your own camera's table, not someone else's.
CFexpress: Type A and Type B are not interchangeable, and VPG does not ladder
The CompactFlash Association describes Type A as the smaller card using one PCIe lane, and Type B as the larger card using two lanes, allowing double the maximum speed. Type B shares its dimensions and connector with XQD. The CompactFlash Association's wording on what follows from that is permissive, not historical: it says some cameras may choose to update their XQD cameras to also support CFexpress Type B cards. That is per-body and per-firmware, not automatic. A Type B card will physically fit an XQD slot whether or not the camera supports it, so check your camera maker's firmware release notes for your exact model before buying, and do not read physical fit as support. The Association also states that at this time there are no cameras or cards that take CFexpress Type C. Type A and Type B are not grades of one thing: Sony's a7 IV takes CFexpress Type A and its manual states flatly that Type B cards cannot be used, while Canon's EOS R5 takes CFexpress Type B in one slot and UHS-II/UHS-I SD in the other.
The R5's two slots are not equivalent, and this is where a reader can waste money while following every other rule on this page. Canon's Shooting chapter lists four things that cannot be recorded to SD cards at all, with the note that pressing the movie shooting button will not start recording: RAW movies, 8K ALL-I, 4K 119.9/100.0 fps (High Frame Rate movies), and 4K 59.94/50.00 fps. No SD speed mark makes an excluded mode work. But Canon's two pages do not agree about that last item. The Shooting chapter writes it as "4K 59.94/50.00fps" with no compression method attached, while the Reference table dashes only the ALL-I variant and publishes SD classes for the rest of that mode: 4K 59.94/50.00 fps IPB takes Video Speed Class 30 at 8-bit and Video Speed Class 60 at 10-bit, and IPB (Light) takes UHS Speed Class 3 at both depths. Those rows are in the table above. Canon qualified the sibling item in the same list — it reads "8K ALL-I", not "8K" — and did not qualify this one. Do not settle that contradiction from this page. If you shoot 4K 60p on an R5, check your own body's current firmware behavior against Canon's current manual, and plan on CFexpress if you need the mode to be certain.
VPG is the CFexpress equivalent of a Video Speed Class. The CompactFlash Association defines it as a guarantee of minimum sustained write performance, where minimum sustained write speed means the fewest MB/s that can be written continuously without dropping frames. VPG800 guarantees 800 MB/s and VPG1600 guarantees 1600 MB/s; VPG200 and VPG400 guarantee 200 and 400 MB/s, inferred from the Association's stated convention that the number in the logo is the minimum sustained write speed, since its profile table is published as an image and its text prints figures only for the two newer classes. Canon's EOS R5 manual instructs using a CFexpress card that supports VPG400, or a card with ample write and read performance, for movie recording.
Here "buy higher" breaks. The CompactFlash Association states that VPG-5 is not backward compatible to VPG-4, and that a higher-performing card supporting the VPG800 or VPG1600 class will not necessarily work with a camera mode that requires VPG200 or VPG400. Within one profile, higher does cover lower — the Association gives VPG400 supporting VPG200, and VPG1600 supporting VPG800 — but across profiles it does not. If your camera asks for VPG200 or VPG400, buy a card carrying that VPG-4 logo, or one carrying both a VPG-4 and a VPG-5 logo, which the Association says indicates support for both profiles. Two further warnings from the same page: some companies may inadvertently or incorrectly use the VPG logo without actually getting their cards certified, and the Association maintains a list of VPG-certified cards you can check a part number against before buying.
When a faster card is not the fix
Canon's EOS R5 manual gives two separate reasons a recording ends on its own, and they call for opposite responses. Under "Recording and image quality", a card with a slow writing speed produces an on-screen indicator, and if that indicator becomes full, movie recording stops automatically. Separately, under the overheating displays, a red icon means the camera will turn off automatically if you keep recording, and after an automatic stop you cannot record again until it has cooled. If your recordings die at roughly the same elapsed time every session with a heat icon on screen, a V90 card will not change that.
A third cause is worth ruling out before you spend anything, because it is free. The SD Association states that write speed to a fragmented area is generally slower than sequential write speed, that Speed Class write is defined to perform sequential writes to a completely un-fragmented area, and that a host may therefore fail to perform Speed Class recording even when unused memory exists in total — in which case the remedy is to rearrange the data or move it to another storage and re-format the card. Canon separately instructs formatting the card with the camera before recording movies, using Low level format before 8K or 4K, and says that when movies cannot be recorded properly you should format the card and try again. So: offload, format in the camera, and retest a correctly-marked card before concluding the card is too slow. Canon also suggests recording a few test movies at your chosen size to confirm the card keeps up.
What to look up on your own equipment
There is no universal answer, because the requirement is set per camera, per mode, and sometimes per bit depth. These are the exact places the three makers cited here publish it.
- Sony: the online Help Guide page "Memory cards that can be used" for your model, split into "For still-image shooting", "For movie recording" and "For S&Q Motion shooting". Check the S&Q section separately even if you have already read the movie section. Read the asterisked footnotes under each table as well as the cells — on the a7 IV they change the requirement for 120fps slow motion and for XAVC S-I 4K at 60fps.
- Canon: "Cards That Can Record Movies" under Movie Recording Quality — read its "Unsupported movie recording" list first — then "Card performance requirements (Movie recording)" in the Reference chapter for the per-mode SD table. For CFexpress detail per quality level, Canon's manual points to the Canon website rather than listing it inline.
- Fujifilm: the per-camera compatibility page on fujifilm-x.com, which states the bitrate-to-class rules and also carries a per-camera card list for that body.
- On the card itself: the class marks are printed on the label, and the bus generation is visible on the back. A single row of contacts means the card cannot be UHS-II or faster, so it cannot legitimately be V60 or V90. Two rows means it can. Check the capacity tier on the label too, alongside the class mark.
- If you shoot microSD: the class marks and bus modes on this page are the same system — the SD Association applies UHS-I, UHS-II, UHS-III and SD Express to SDHC, SDXC and SDUC cards, and defines an SD Express microSD spec version. What differs is the physical card and the adapter. Sony's a7 IV help guide, for example, instructs that when using microSD cards with the camera you must use the appropriate adaptor. Confirm your own camera's note on adapters before relying on one for video.
Out of scope here: any claim about how a specific brand of card performs in practice, since that would require testing this publisher has not done. Also out of scope, on this site generally, are third-party adapters and undocumented combinations. If your open question is about glass rather than storage, see the lens mount guide for whether a lens will physically mount and keep autofocus, and the sensor format guide for reading a focal length and aperture across sensor sizes.
Check it on your own equipment
These take you to the manufacturers and standards bodies the page draws on, so you can look up your exact model.
- Standards reference
SD Association: Speed Class reference (opens in a new tab)The four class systems with their members, which bus family each mark may be applied to (including that V60 and V90 are UHS-II/UHS-III only), and the warning — in the 'Best Combination' section — that mixing class systems between host and card does not deliver the expected write speed. The fragmentation section at the bottom is what to read before blaming a card. — www.sdcard.org - Standards reference
CompactFlash Association: Video Performance Guarantee (VPG) (opens in a new tab)The definition of VPG and of minimum sustained write speed, and — in the note under the profile table and again in the FAQ — the statement that VPG-5 is not backward compatible with VPG-4, so a VPG800 or VPG1600 card will not necessarily work in a mode requiring VPG200 or VPG400. Read this before buying any CFexpress card for video. — compactflash.org - Standards reference
CompactFlash Association: List of VPG-Certified Cards (opens in a new tab)A searchable table of cards that passed CFA's certification protocol, with separate columns for the VPG-4 classes (200, 400) and the VPG-5 classes (800, 1600), plus company, card type, capacity, product name and part number. Check a part number here before you buy: the Association warns that some companies use the VPG logo without certification. This is a certification registry, not a ranking or a recommendation. — compactflash.org - Manufacturer specification
Canon EOS R5 manual: Card performance requirements (Movie recording) (opens in a new tab)Canon's full per-mode table, with separate 8 bit and 10 bit SD columns and a single CFexpress column that reads "Refer to the Canon website" in every row. It covers rows this page does not reproduce, including Full HD variants and time-lapse movies, and it is where you can check the 4K 59.94/50.00 fps IPB rows against the exclusion list in the Shooting chapter. — cam.start.canon - Official support page
Sony a7 IV Help Guide: Memory cards that can be used (opens in a new tab)Sony's per-format card table split into still-image, movie recording and S&Q Motion sections, showing the different card requirements for the same bitrate in normal versus slow-motion recording, the two asterisked footnotes under the S&Q table, and the notes on CFexpress Type B and microSD adaptors. For your own body, search Sony's help guide index for your model and open its own 'Memory cards that can be used' page — the URL differs per camera in both path segments, so editing this one will not work. — helpguide.sony.net
What this page does not tell you
- Nothing on this page was tested or measured by the publisher. Every speed figure is reproduced from a standards body, a camera maker's own document, or SanDisk's support documentation, and the citation names the exact page read and the date it was read.
- The manufacturer tables reproduced here are for three specific bodies — the Sony a7 IV (ILCE-7M4), the Canon EOS R5 and the Fujifilm X-T5. They do not transfer to other models, including other models from the same maker. Requirements are set per camera, per recording mode, and on the R5 per bit depth.
- This page cannot tell you why a maker's required class exceeds the arithmetic from its own stated bitrate, or why the margin ranges from 1.2x to 3.2x across the published cases. The makers publish the requirement, not the reasoning. Use the division by eight only to rule cards out, never to rule one in.
- Canon's own documentation is internally inconsistent about one mode on the EOS R5. Its Shooting chapter lists 4K 59.94/50.00 fps among the modes that cannot be recorded to SD at all, without naming a compression method; its Reference table dashes only the ALL-I variant and publishes SD classes for IPB and IPB (Light). This publisher cannot say which page reflects current firmware, and has not tested the camera. If that mode matters to you, verify it on your own body before buying an SD card for it.
- What an SD Express card does in a UHS-II or UHS-I host is not stated on either SD Association page read here, and SanDisk's fallback statement covers UHS-II cards only. If you are considering an SD Express card for a UHS-II body, get that answer from the card maker for your specific card before buying.
- Class marks are minimum guarantees for a card in good condition on a compatible bus. They do not predict how a particular card behaves once it is heavily fragmented, nor how any specific brand or production batch performs; that would require testing this publisher has not done.
- Manufacturer requirement tables change with firmware, and new recording modes can arrive with new card requirements. Re-check your own camera's current manual rather than relying on a table copied at a point in time.
- Retailer product listings and marketing copy were not used to establish any technical claim on this page.
Sources
Manufacturers revise specifications. Every source below is dated — open it before you buy.
- The SD Association defines four speed class systems: Speed Class, UHS Speed Class, Video Speed Class and SD Express Speed Class.
- The members of each system are Class 2/4/6/10, U1 and U3, V6/V10/V30/V60/V90, and E150/E300/E450/E600.
- A speed class symbol with a number indicates the minimum writing speed.
- Class 10 is used in High Speed mode or faster and can be applied to the High Speed bus interface product family.
- U1 and U3 are used in SDR50/DDR50 or faster and can be applied to the UHS bus interface family, meaning UHS-I, UHS-II and UHS-III.
- V6 and V10 may be applied to the High Speed and UHS bus interface families; V30 may be applied to the UHS family; V60 and V90 are used in UHS-II mode or faster and may be applied only to UHS-II / UHS-III.
- The SD Express Speed Class marks E150, E300, E450 and E600 are used in SD Express mode and apply to the SD Express bus interface family.
- The E150/E300/E450/E600 numbers represent the minimum write speed in MB/s.
- The SD Association advises choosing a card whose class symbol is the same as or higher than the class symbol indicated by the host device, and gives the example that a Speed Class 4 host can use Class 4, 6 or 10 cards.
- The SD Association warns that expected write speed will not be available from a combination of different class symbols between host and card, giving Host Class 10 with Card U1 and Host U1 with Card V10 as examples, even though those marks name the same 10 MB/s write speed.
- The SD Association states that write speed to a fragmented area is generally slower than sequential write speed, that Speed Class write is defined to perform sequential writes to a completely un-fragmented area, that a host may be unable to perform Speed Class recording even when unused memory exists in total, and that the remedy is to rearrange data or move it to another storage and re-format the card.
- Minimum write speeds are: Class 2 = 2 MB/s, Class 4 = 4, Class 6 = 6, Class 10 = 10; U1 = 10, U3 = 30; V6 = 6, V10 = 10, V30 = 30, V60 = 60, V90 = 90.
- U3 and V30 are both 30 MB/s minimums.
- A card's rated speed is its maximum and approximately what to expect in typical use, while a Speed Class is a minimum based on a worst-case scenario test that reflects the sustained speed needed for even-rate video recording.
- A card's maximum rated speed, rather than its class minimum, is what matters when clearing a camera's burst buffer.
- Fujifilm names either UHS Speed Class 3 or Video Speed Class V30 for the same recording mode, treating marks from two systems as satisfying one requirement.
- SD bus maximums are: Default Speed 12.5 MB/s; High Speed 25 MB/s; UHS-I 50 MB/s (SDR50, DDR50) and 104 MB/s (SDR104); UHS-II 156 MB/s full duplex and 312 MB/s half duplex; UHS-III 312 MB/s and 624 MB/s full duplex; SD Express 985 MB/s (PCIe Gen.3 x1), 1970 MB/s (Gen.4 x1 or Gen.3 x2) and 3940 MB/s (Gen.4 x2).
- UHS-I achieves its speeds using one row of pins, while UHS-II, UHS-III and SD Express use two lanes for data transfer via two rows of pins.
- The UHS-I, UHS-II, UHS-III and SD Express bus interfaces are available for SDHC, SDXC and SDUC memory cards.
- The SD Association defines an SD Express specification version for microSD.
- A genuine V60 or V90 SD card necessarily has two rows of contacts.
- A UHS-II card can be used in UHS-I and non-UHS host devices, but the slower UHS-I or SD max speed is what gets used; UHS-II max speeds are obtained only when both card and host support UHS-II.
- Buying a UHS-II card does not raise the speed of a UHS-I slot.
- Neither SD Association page read here states what speed an SD Express card runs at in a UHS-II host, and SanDisk's fallback statement covers UHS-II cards only.
- SanDisk gives capacity ranges of 128MB–2GB for SD, 4GB–32GB for SDHC and 64GB–2TB for SDXC, and states that SDXC cards can only be used with SDXC hosts and will not work with SD and SDHC hosts, while SDXC hosts support SD, SDHC and SDXC cards.
- A card meeting a row's class mark but not its named capacity tier does not satisfy that row.
- Dividing a stated bitrate in Mbps by eight gives the average write load in MB/s: 600 Mbps = 75 MB/s, 360 = 45, 222 = 27.75, 200 = 25, 100 = 12.5, 60 = 7.5.
- In every published case on this page the class the maker requires exceeds the average write load computed from the stated bitrate, by ratios ranging from 1.2x to 3.2x; the largest gap is Sony's XAVC S-I HD, where 222 Mbps divides to 27.75 MB/s but Sony requires V90, a 90 MB/s minimum.
- For the Sony a7 IV in normal movie recording, XAVC HS 4K and XAVC S 4K at 200 Mbps and XAVC S HD at 100 Mbps take an SDHC/SDXC card of U3 or V30 or better, or a CFexpress Type A card.
- For the Sony a7 IV, when the recording bit rate is 60 Mbps or lower you can also record to an SDHC/SDXC Class 10 card.
- For the Sony a7 IV, XAVC S-I 4K at 600 Mbps and XAVC S-I HD at 222 Mbps require an SDXC V90 card or a CFexpress Type A card of VPG200 or higher, in both normal recording and S&Q Motion — except that a footnote removes the SD option for XAVC S-I 4K in S&Q Motion when Rec Frame Rate is 30p/25p/24p and Frame Rate is 60fps/50fps.
- For the Sony a7 IV in S&Q Motion, XAVC HS 4K and XAVC S 4K at 200 Mbps require an SDXC V60 card or better, or a CFexpress Type A card of VPG200 or higher — stricter than the same formats at the same bitrate in normal recording — while XAVC S HD at 100 Mbps stays at SDHC/SDXC U3 or V30 or better in the cell, subject to a footnote that raises it to SDXC V60 or CFexpress Type A VPG200 for 120fps/100fps at a 50 Mbps bit rate.
- Sony's S&Q Motion table footnote *1, attached to the XAVC S HD 100 Mbps row, states that when Rec Frame Rate is set to 30p/25p/24p, Frame Rate is set to 120fps/100fps and the recordable bit rate is set to 50 Mbps, an SDXC card (V60 or higher) or a CFexpress Type A memory card (VPG200 or higher) is required.
- Sony's S&Q Motion table footnote *2, attached to the XAVC S-I 4K 600 Mbps row, states that when Rec Frame Rate is set to 30p/25p/24p and Frame Rate is set to 60fps/50fps for slow-motion recording, a CFexpress Type A memory card (VPG200 or higher) is required, naming no SD card.
- Sony states that CFexpress Type B memory cards cannot be used in the a7 IV.
- Sony instructs that when using microSD memory cards with the a7 IV you must use the appropriate adaptor.
- The Sony help guide page is titled "Memory cards that can be used" and is divided into sections for still-image shooting, movie recording, and S&Q Motion shooting.
- Sony's help guide URL cannot be edited to reach another camera's equivalent page: both the product folder and the topic ID differ per model, and substituting other folder numbers into the a7 IV topic URL returns HTTP 404.
- For the Fujifilm X-T5, movies at a bit rate of 360 Mbps can be recorded to SDHC/SDXC cards with a Video Speed Class of V60 or better.
- For the Fujifilm X-T5, movies at 100 or 200 Mbps require SDHC/SDXC cards of UHS Speed Class 3 or Video Speed Class V30 or better.
- Fujifilm recommends a UHS-II memory card for high-speed burst stills on the X-T5 and publishes a per-camera card compatibility list, giving SDHC as 4–32GB and SDXC as 64GB–2TB.
- Sony requires V60 for 200 Mbps in S&Q while Fujifilm accepts U3/V30 for 200 Mbps, so the same stated bitrate does not imply the same card requirement across makers.
- CFexpress Type A is smaller and uses one PCIe lane, while Type B is larger and uses two PCIe lanes, allowing double the maximum speed.
- CFexpress Type B cards have the same dimension and connector as XQD cards, and the CompactFlash Association states that some cameras may choose to update their XQD cameras to also support CFexpress Type B cards.
- A CFexpress Type B card physically fitting an XQD slot does not establish that the camera supports it; support is per body and per firmware.
- There are currently no cameras or cards that take CFexpress Type C.
- VPG is a CompactFlash Association standard guaranteeing minimum sustained write performance for recording high-quality video, where minimum sustained write speed is the fewest MB/s that can be written continuously without dropping frames.
- VPG800 guarantees 800 MB/s sustained write speed and VPG1600 guarantees 1600 MB/s.
- VPG200 guarantees 200 MB/s and VPG400 guarantees 400 MB/s.
- The CompactFlash Association states that VPG-5 is not backward compatible to VPG-4, and that a higher-performing card supporting VPG800 or VPG1600 will not necessarily work with a camera mode that requires VPG200 or VPG400.
- Within a single VPG profile a higher class supports the lower class: the Association gives VPG400 supporting VPG200 in Profile 4, and VPG1600 supporting VPG800 in Profile 5.
- A card showing both a VPG-4 logo (VPG200 or VPG400) and a VPG-5 logo (VPG800 or VPG1600) supports both VPG-4 and VPG-5 camera profiles.
- The CompactFlash Association warns that some companies may inadvertently or incorrectly use the VPG logo without getting their cards CFA-certified, and maintains a list of VPG-certified memory cards users can check against.
- The CompactFlash Association's list of VPG-certified cards is published as a table naming company, card type, card size, product name and part number, with separate columns for the VPG-4 classes (200, 400) and the VPG-5 classes (800, 1600).
- The Canon EOS R5 accepts CFexpress Type-B cards in one slot and SD/SDHC/SDXC cards with UHS-II and UHS-I supported in the other.
- Canon instructs that for movie recording on the EOS R5 you use a CFexpress card that supports VPG400, or a card with ample performance meaning fast enough writing and reading speeds for the movie recording quality.
- Canon states that the following files cannot be recorded to SD cards on the EOS R5 and that pressing the movie shooting button will not start recording: RAW movies, 8K ALL-I, 4K 119.9/100.0 fps (High Frame Rate movies), and 4K 59.94/50.00 fps.
- Canon's "Unsupported movie recording" list writes the excluded 8K item as "8K ALL-I" but writes the excluded 4K 59.94/50.00 fps item with no compression method attached.
- Canon's EOS R5 "Cards That Can Record Movies" section directs readers to the Canon website for CFexpress detail per movie recording quality and to a "Card performance requirements" section for SD cards, and advises testing cards by recording a few movies at the specified size.
- Canon instructs formatting the card with the camera before recording movies for better card performance, using Low level format before recording 8K or 4K movies, and formatting the card and trying again when movies cannot be recorded properly.
- Canon's EOS R5 "Card performance requirements (Movie recording)" table gives, for SD cards: 8K RAW and 8K ALL-I not available; 8K IPB Video Speed Class 60 (8-bit) and Video Speed Class 90 (10-bit); 8K IPB (Light) UHS Speed Class 3 (8-bit) and Video Speed Class 60 (10-bit); 4K 119.88/100.00 fps ALL-I not available; 4K 59.94/50.00 fps ALL-I not available, but 4K 59.94/50.00 fps IPB Video Speed Class 30 (8-bit) and Video Speed Class 60 (10-bit) and 4K 59.94/50.00 fps IPB (Light) UHS Speed Class 3 at both depths; other 4K ALL-I Video Speed Class 60 at both depths; other 4K IPB UHS Speed Class 3 at both depths; Full HD 59.94/50.00 fps IPB SD Speed Class 10 (8-bit) and UHS Speed Class 3 (10-bit).
- Canon's card performance requirements table prints "Refer to the Canon website" in its CFexpress column for every row, not only for 8K RAW.
- Canon's Shooting chapter and Canon's Reference table disagree about whether 4K 59.94/50.00 fps IPB and IPB (Light) can be recorded to an SD card on the EOS R5.
- On the Canon EOS R5 the same movie recording size can require a different SD speed class at 10-bit than at 8-bit.
- Canon's EOS R5 SD card table uses marks from three different SD Association systems — SD Speed Class, UHS Speed Class and Video Speed Class — in different rows.
- On the Canon EOS R5, a card with a slow writing speed produces an on-screen indicator during movie recording, and if that indicator becomes full, movie recording stops automatically.
- On the Canon EOS R5, overheating is a separate cause of recording stopping: a red icon means the camera will turn off automatically if recording continues, and after an automatic stop you cannot record movies or shoot stills until the camera has cooled.