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I have noticed that two cards -one CF and one SD - from the same manufacturer, with the same specifications have a significant difference in cost. The CF card costs several times more than the SD card. What is the reason for this price difference? Do CF cards have any significant advantage over SD cards in any way?

Evan Pak
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  • The last time I looked at both formats, the top tier CF cards were rated for more extreme temperatures and higher altitudes than their SD counterparts. This probably has to do with their more rigid construction. This has little to nothing to do with the price disparity. That is mostly related to supply and demand. – Michael C May 08 '13 at 09:25

3 Answers3

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There is an advantage to Compact-Flash cards which you get with the fastest models and sufficiently fast camera. This is not what accounts for most of the price difference, volume is. SD cards are sold on considerably higher volume than CF ones. When CF cards were more popular, it used to be the opposite.

Nowadays, I would not worry at all about this. The most advantageous card is the one that fits in your camera! If you are choosing a camera, there are certainly much more significant differences to worry about than what memory cards they take. For a camera that accepts both, if you want the fastest get CF. If you want to replication, you will need both.

BTW, I have covered the technical differences here. They do not explain the price difference but may be interesting to know.

Community
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Itai
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The main difference in cost probably comes from economies of scale. For a long time SD cards were more expensive, but now they've become cheaper as they've become easier to manufacture and require less materials. Meanwhile, due to their bulk, consumers have fallen out of favor with CF and prefer SD.

Additionally, the architecture of the cards is different. For SD, the controller for reading the card resides in the reader and thus readers cost more but cards cost less (but are limited by the reader). For CF on the other hand, the controller resides in the card. This allows for some interesting things like the old Microdrives that were actual hard drives inside a CF card. There were also devices like wifi modems and barcode scanners built in to CF cards. Since the controller resides in the card however, it means extra expense in the production of the cards. The faster the card, the better the controller has to be and the bigger the cost difference to a comparable SD card.

As far as which is better, it really depends on the two cards and the reader being used.

AJ Henderson
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  • "There were also devices like wifi modems and barcode scanners built in to CF cards": how come eye fi cards dont exist for CF, but do for SD? – Michael Nielsen May 07 '13 at 17:22
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    I don't the part about controllers is correct. That's true for xD (and its ironically-named predecessor SmartMedia), but not for either SD or CF. The SD interface acts as block storage. (A better controller is one of the things that can make more expensive SD cards better, incidentally.) – mattdm May 07 '13 at 17:24
  • @MichaelNielsen - that's a good question. My guess is that there isn't enough of a CF market anymore. In their time an awful lot of devices existed for CF though. – AJ Henderson May 07 '13 at 17:41
  • From wikipedia "CompactFlash IDE mode defines an interface that is smaller than, but electrically identical to, the ATA interface. The CF device contains an ATA controller and appears to the host device as if it were a hard disk" – AJ Henderson May 07 '13 at 17:52
  • @mattdm - removed my old comment as I finally found the supporting information on wikipedia. I knew I had seen it somewhere when researching which to use as my primary. – AJ Henderson May 07 '13 at 17:54
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    Riiight, but the SD Card also has a controller built in, just not an ATA-compatible interface. You need a specialized adapter on the host if you want to, for example, boot from the card, but that's not relevant to cameras. – mattdm May 07 '13 at 17:55
  • @mattdm - was just seeing that. I think the SD interface is simpler though isn't it, or at least it can be for minimal functionality (obviously in something like an eyefi it will be more complex). I'm running off what I remember from when I researched this more heavily about 10 months ago, so it's a bit foggy. I suppose I could be just getting thoughts crossed with xD too. – AJ Henderson May 07 '13 at 18:05
  • I haven't studied it extensively, but, yeah, I think it is simplified; on the other hand I think they're both simple enough that it's not a big factor in the costs. Here I'm totally speculating, though. – mattdm May 07 '13 at 18:15
  • @mattdm - that could be. From what I remember it was more of a performance thing than a cost thing when I read about it. But again, it's something I read in passing so I was just throwing it out there as a possibility. I remember it was part of the difference in cost between a CF reader and an SD reader back in the day, but that's cost on the reader side rather than the card itself. – AJ Henderson May 07 '13 at 18:20
  • CF was basically just an alternate form factor for PCMCIA/PC cards, which meant that almost anything that could run on an ISA (Type I) or EISA (Type II) system bus was fair game, often with a dongle and a breakout box many times larger than the card. –  May 09 '13 at 00:33
  • @AJ This is an old conversation, but this just came up today and I thought you might find it interesting (and maybe even slightly relevant): On Hacking MicroSD Cards. – mattdm Dec 30 '13 at 06:30
  • @mattdm - thanks, that is an awesome article, though I think the controller in that case is for making the storage work the way you would expect, but it is fascinating to see more of how SD works. – AJ Henderson Dec 30 '13 at 14:24
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Compactflash cards are much more sturdy. SD cards flex and get squashed, so unless you have them on your camera (like if you carry extra like most serious photographers) it is much better to use CF cards. They also have better bandwidth with more pins, but mostly you wont notice that since the camera interface and cardreaders cannot fully utilize it unless you get the best of the best gear. You can get 10$ cardreaders and 50$ cardreaders, and you really feel the difference. I had a sandisk extreme III CF card and used a 10$ reader, and the transfer time was 1.5mb/s. Then I got a sandisk extreme reader for 50$ and suddenly it was 20mb/s. The studiness feature is so high a priority for me that I look for the CF slot in camera specs as a dealbreaker kinda thing. Ive had too many SD cards break , and seen other people complain that all their confeirence shots were lost on a sd card, that I avoid them. I've never seen a broken CF card. Not that I claim it cant happen, just that the frequency is so low that I havent encountered one, in the same time I encountered multiple broken SD cards.

Michael Nielsen
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    re bandwidth - I just bought an SD card with claimed "Up to 95 MB/s" performance. (Sandisk Extreme Pro 8 GB). Actual transfer rate unknown. It cost 50% more than their 30 MB/s (claimed) card and was bought to assist in troubleshooting specific camera problems. FWIW - even if the camera could write that fast it would not keep up with my A77 max rate of 12 x say 12 MB Ultrafine JPG frames/second. | Tries it: Wow! 14 frames, 182 MB in just over one second. Buffer cleared in 4 manually counted seconds for about 45 MB/s. Some more formal tests are in order ! :-). – Russell McMahon May 07 '13 at 21:53
  • Breakage: I find that micro SD to SD adapters break far too easily. On full size SD card leading corner can break. Will not insert without repair. Write protect sliders can vanish - must replace to write. // CF - never a problem mechanically. – Russell McMahon May 07 '13 at 21:55