What is CFexpress? The new camera memory card format explained

What’s CFexpress? The brand new digital camera reminiscence card format defined


(Picture credit score: Future)

You will have heard: there’s a brand new form of reminiscence card on the town, and it’s referred to as CFexpress. 

CFexpress playing cards appear to be a pocket-drainer at first look, beginning at $199.99 / £210 for 80GB. However they’re vital if you wish to make the most of the newest digital camera options, together with 8K video seize, in-camera uncompressed video recording and ultra-rapid burst modes. 

New cameras just like the Sony A7S III and Canon EOS R5 have put CFexpress within the highlight, however it’s not a brand-new format. It was introduced in 2016, and the primary playing cards got here out in 2017, with the Nikon Z6 and Z7, and Canon EOS C500 Mark II video digital camera among the many first fashions to have a CFexpress slot.

There’s just a little extra to study CFexpress playing cards, apart from that they price greater than SD playing cards, although. Right here’s all the things it is advisable to know.

Do we actually want one other digital camera reminiscence card format?

The idea of bottlenecks explains why we want CFexpress playing cards. When a brand new digital camera comes alongside and provides fast-than-ever burst modes or higher-resolution video at better body charges, the processor or sensor’s uncooked capabilities normally get the credit score. 

Nevertheless, the picture buffer, the storage wafer in your reminiscence card, and the storage controller all must be as much as the job too, and the CFexpress format handles the final two of those. 

Its playing cards use PCIe 3.0, the identical interface utilized by laptop computer and desktop SSDs – and these are radically sooner than the SD playing cards most of us use at the moment. 

SD playing cards use a unique interface. A high-spec UHS-III card has a most theoretical pace of round 624MB/s, whereas the usII playing cards you may readily purchase faucet out at 312MB/s.


(Picture credit score: Future)

CFexpress raises that to 4GB/s for the quickest, Sort C variant, in keeping with the pace of the principle storage drive of a high-end laptop computer. 

The SD Affiliation, the group that administers SD card requirements, has provide you with a substitute for CFexpress. It’s referred to as SD Specific, and makes use of the identical PCIe 3.Zero interface whereas providing related max speeds of 4GB/s.

However simply as SD kind of steamrolled Compact Flash for years, plainly CFexpress has already gained this combat – and its use in cameras just like the Sony A7S III is proof sufficient. 

SD Specific additionally arrived three years after CFexpress, giving the latter a major head begin. 

What sort of CFexpress playing cards are there?

CFexpress playing cards are sooner – and that’s the massive takeaway, if it’s all of your mind has house for. However issues are about to get just a little extra sophisticated. 

There are three CFexpress variants: Sort A, Sort B and Sort C. The 2 newer ones, A and C, have been launched when the CompactFlash Affiliation revised the usual to ‘2.0’ in 2019.

Sort A has one PCIe 3.Zero pipeline, for a most 1GB/s pace, Sort B has two pipelines, doubling the headroom to 2GB/s, and Sort C has 4 pipelines for, you guessed it, that headline-grabbing 4GB/s most knowledge switch fee. 


(Picture credit score: Future)

You may presently purchase Sort A and Sort B playing cards. And, like SD playing cards, you also needs to take a look at their sustained write speeds, reasonably than simply these printed on the cardboard and its packaging. 

For instance, the Sony Robust UHS-II sequence of SD playing cards is rated for 299MB/s write speeds, however solely supplies (minimal) 90MB/s sustained write speeds. In the meantime, the Sony Robust CFexpress sequence, primarily based on the Sort A normal, provides burst write speeds of 700MB/s, and sustained writes at 400MB/s. 

Velocity losses when doing one thing like taking pictures video are a lot decrease in a well-designed CFexpress card. 

But when CFexpress Sort C is quicker, why wouldn’t you decide it each time?

As you may see within the diagram above, the three varieties of CFexpress card will not be the identical dimension. Sort A playing cards are the smallest at 28mm x 20mm x 2.8mm, which is barely smaller and barely thicker than an ordinary SD card. 

Sort B playing cards measure 38.5 x 29.eight x 3.8mm, the identical form as XQD reminiscence playing cards, whereas Sort C playing cards are a lot bigger at 54 x 74 x 4.8mm – that’s far bigger and thicker than even the basic CompactFlash card of years passed by. 

At current, no cameras use the CFexpress Sort C customary. A number of help Sort B, together with the Nikon Z6 and Z7. Most cameras with XQD slots also can use some Sort B playing cards, however naturally you’ll be restricted to the decrease pace of that format’s interface.


(Picture credit score: Future)

The Sony Alpha A7S III (above) is the primary digital camera to help CFexpress Sort A, and this essentially the most fascinating format of the second. Sure, it could supply the bottom efficiency of the lot, however these playing cards can match right into a combi slot that may also take SD playing cards. 

The A7S III has two card slots, each of which is able to settle for SD and CFexpress playing cards. 

As for the sorts of photographers who will undertake CFexpress within the subsequent couple of years, execs and lovers with cash to spend are more likely to more and more select CFexpress, whereas SD will nonetheless be there for these with a lower-end digital camera, or those that don’t want top-tier write efficiency. 

Who makes CFexpress playing cards and the way a lot do they price?

There’s no getting away from the truth that many photographers will discover CFexpress playing cards prohibitively costly. 

Many of the large names in SD playing cards are already on-board with this newer format, with Sony, Delkin, SanDisk, Lexar, ProGrade and Integral all producing CFexpress Sort B playing cards. 

There’s a major distinction within the costs of playing cards from these totally different manufacturers. Integral and ProGrade present the cheaper choices, however might miss a characteristic or two; for instance, ProGrade playing cards have a tendency to not have an IP score, which tells you the water and dirt resistance of a product, though we now have no complaints about their pace specs.


(Picture credit score: Future)

ProGrade Gold playing cards declare 400MB/s sustained write speeds, and its Cobalt vary provides unbelievable sustained writes of 1400MB/s or 1500MB/s – it varies between storage ranges – and also you gained’t discover higher in a Sort B card, as of mid-2020. 

Gold playing cards price $179 / £193.99 (128GB), $399 / £279 (256GB), $399 / £499 (512GB), and $899 / £819 (1TB).

Extremely-high efficiency Cobalt playing cards are $359 / £389 (325GB) and $899 / £799 (650GB). These seem like the quickest CFexpress Sort B playing cards cash can purchase in the meanwhile.

Integral CFexpress playing cards are among the many most cost-effective round, however make no ruggedisation claims, and solely seem to quote burst pace figures. Nevertheless, at round £165 for the 128GB card (integral playing cards are a lot simpler to seek out within the UK and Europe than the US), they’re fairly enticing. 

Sony’s Robust CFexpress sequence is the best choice for journey use. They’re made to a few occasions the power of the CFexpress customary in response to Sony, and examined to resist 70 newtons of bending power and 5-meter drops. An IP57 score additionally means they’re extremely water and dirt resistant. 

A Sony Robust card prices $219 / £299 (128GB), $399 / £483 (256GB) or $649 / £999 (512GB).

CFexpress card

(Picture credit score: SanDIsk)

SanDisk’s extremely regarded Excessive Professional sequence are a strong mid-price choice, and would be the first selection for a lot of. These price $199 / £279 (128GB), $399 / £449 (256GB) or $599 / £699 (512GB), and include a ‘lifetime’ restricted guarantee that covers failure, however not wear-and-tear otherwise you by chance snapping them. 

Sony is the one firm making CFexpress Sort A playing cards on the time of writing, and these are, sadly, much more costly than the Sort B sort, at $199 / £209 for 80GB, rising to $649 for 512GB.  

What’s the takeaway right here? Costs fluctuate between nations fairly considerably at greater capacities, and ProGrade’s Cobalt sequence CFexpress playing cards seem to supply one of the best steady write efficiency accessible in 2020. 

What’s subsequent for CFexpress?

The subsequent stage for CFexpress is PCIe 4.0, which can include the format’s subsequent large revision. This may double the bandwidth per lane, so a theoretical CFexpress 3.Zero card would possibly supply 2GB/s pace for Sort A sizes, 4GB/s for Sort B, and 8GB/s for Sort C. 

We’re extremely more likely to see this introduced sooner or later, as a result of arch CFexpress-rival the SD Affiliation has already introduced PCIe 4.Zero integration for a future model of SD Specific playing cards; nonetheless, don’t count on to see these playing cards on sale for a few years not less than.

There’s nonetheless a query mark over Sort C playing cards on the whole, earlier than we even take into consideration the subsequent CFexpress customary. You may’t purchase them but, and it’s important to marvel which cameras, or different units, would possibly take the dimensions hit by way of design as a trade-off in an effort to profit from its 4GB/s most pace.


(Picture credit score: SD affiliation)

Much more intensive video seize modes are the apparent use, however do we actually want 4GB/s? The effectivity of the HEVC encoding format means you gained’t want something like that knowledge fee even at 8K 120fps. 

Storage of uncompressed video is a way more apparent use case for all that bandwidth. That is usually executed over HDMI, as a 2.1-version connector has 48Gbps bandwidth (6GB/s). So whereas a CFexpress Sort C card isn’t fairly as fats a pipe as HDMI, it comes a lot nearer than the playing cards we now have at the moment, and would allow you to retailer extremely excessive data-rate footage in-camera. 

What we’re actually ready for is one thing a lot easier: decrease costs. 

We hope the price of 64-256GB CFexpress playing cards will begin to drop as manufacturing scales up, however don’t count on miracles – a 256GB UHS-II SD card with a V90 score (steady 90MB/s write pace) can nonetheless price round $250, so there’s much less stress for CFexpress costs to freefall within the subsequent 12 months.  

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