# SDHC vs Compactflash



## Richard8971 (Dec 8, 2013)

I'm sure this subject has been discussed but I am curious. For the most part, the "memory card wars" have "ended" with two major players. SDHC and CompactFlash.

Now, if memory serves, compactflash, was for a while, faster and had larger capacities available than SDHC. But I've noticed lately that SDHC cards are just as fast, have almost a high as memory capacity, for the most part. I mean CompactFlash Extreme Pro has 256GB cards and SDHC has 128GB and 64GB cards available. I would imagine that 64GB cards are about as high as most people carry around, unless you are a professional and you need a larger card.

My wife's Nikon D7000 and D7100 have dual SDHC slots. Pretty sweet I think, but my poor 7D has 1 compactflash card available. This is ONE feature I would like to see in Canon bodies. The 5D3 dual slots don't count as they are mixed AND the SDHC slot doesn't transfer as fast as the CF slot.

Canon and Nikon have both not standardized memory card usage. In saying that, both Canon and Nikon use CompactFlash cards on the higher end bodies and SDHC on the "lesser" bodies.

Now that SDHC cards are faster and have higher capacities is there an advantage anymore? I know that a lot of people don't like putting all of their photos on large cards just in case there is a failure. I think 32GB/64GB is about maximum I would go.

Not that I really care, BUT compactflash cards ARE almost twice as much as equivalent SDHC cards. I bought a 32GB extreme pro card for my 7D and it was $140.00 while I spent that much buying TWO SDHC 32GB extreme pro cards for my wife's D7100. Not to mention that now she has 64GB if shooting room vs my 32GB on her D7100 and 2 64GB extreme SDHC cards in her D7000!

D


----------



## viggen61 (Dec 8, 2013)

In many cases, CF is still after than SDHC. Take your [Sandisk] "Extreme Pro" cards.

SanDisk rates the SDHC "Extreme Pro" cards at 95MB/s read, 90MB/s write. Contrast that with the SanDisk CF "Extreme Pro" cards at 160MB/s read, 150MB/s write. By my math, that makes the CFs 67% faster than the SDHC.

So, yes, you are paying as much as double, but you are getting a considerable speed boost. On the other hand, if you bought a CF card that was closer to the same speed your SD card was, the cost difference would be much less.

As for capacity, the "Extreme Pro" SD tops out at 64GB, while the same "Extreme Pro" in CF tops out 4 times that size at 256GB... There's simply more real estate to use inside the plastic on the CFs.

Names like "Extreme Pro" can't really be used across product lines for a direct comparison. You really need to dig into the specifications to be absolutely sure you're getting the same performance.


----------



## Richard8971 (Dec 8, 2013)

viggen61 said:


> SanDisk rates the SDHC "Extreme Pro" cards at 95MB/s read, 90MB/s write. Contrast that with the SanDisk CF "Extreme Pro" cards at 160MB/s read, 150MB/s write. By my math, that makes the CFs 67% faster than the SDHC.
> 
> So, yes, you are paying as much as double, but you are getting a considerable speed boost. On the other hand, if you bought a CF card that was closer to the same speed your SD card was, the cost difference would be much less.



The extreme pro cards were JUST released with those higher speeds. About 2 months ago they were 'identical' to the SDHC cards. My camera can't write to the "new" extreme pro cards at 150MB a sec, so it doesn't matter in that regard. Even when the extreme pro SDHC cards were rated at the same speed as the CF cards, they were still twice as much.

And I am talking about card vs card. Again, I don't know very many, in fact, none who own cards larger than 64GB and even many of those in the cheaper cards, not high end. (extreme cards vs extreme pro cards) At 128GB and 256GB the prices get ridiculous, almost insane, so I am not talking about those cards. 

D


----------



## al-toidz photography (Dec 8, 2013)

One thing that you might want to consider is what type of computer/laptop you have. For example, i have a 1ds mark 3 and although i can use both CF and Sdhc, i prefer to use SD card because i have macbook pro. It has a built in SD slot and therefore it is much easier and convinient to use.

Just my 2 cents


----------



## neuroanatomist (Dec 8, 2013)

Do both CF and SD cards live up to their spec? What matters is real-world performance. For example, FW400 is spec'd at 400 Mbps (duh) and USB2 is spec'd faster at 480 Mbps - but for real-world sustained data transfer, FW400 mops the floor with USB2.


----------



## Marsu42 (Dec 8, 2013)

Richard8971 said:


> Canon and Nikon have both not standardized memory card usage. In saying that, both Canon and Nikon use CompactFlash cards on the higher end bodies and SDHC on the "lesser" bodies.



It will probably stay this way because 4k raw video needs max. throughput, and it seems the larger cf design leaves more space for innovations. For everything else, *if* manufacturers would adopt the newest specs asap (which they don't) sd should be sufficient for general video and burst stills, so the division is seems to be some marketing (cf is "pro") and some customer protection as seen in the 5d3's cf/sd, nobody wants to throw away all his/her cards when upgrading to a newer camera.

From a customer's perspective cf is probably better because it prevents manufacturers from crippling the transfer speed like in the current Canon's sd cameras, that's why the 50d/7d are much better for (raw) video than 60d/70d.


----------



## JPAZ (Dec 8, 2013)

Form a practical standpoint, size might matter. Even if a 64GB CF and a 64GB SD had identical data transfer rates, I personally find the smaller card more difficult to change in the field. I have dropped the smaller cards a lot more frequently than you'd imagine. For me, especially in weather extremes, the CF is just easier to handle. YMMV.


----------



## Richard8971 (Dec 8, 2013)

JPAZ said:


> Form a practical standpoint, size might matter. Even if a 64GB CF and a 64GB SD had identical data transfer rates, I personally find the smaller card more difficult to change in the field. I have dropped the smaller cards a lot more frequently than you'd imagine. For me, especially in weather extremes, the CF is just easier to handle. YMMV.



I agree with this one. I like the CF cards more because they ARE larger and easier to handle. I see where everyone is coming from though in regards to both cards.

D


----------



## candc (Dec 8, 2013)

I like the SD cards because they are convienant and cheaper. My laptop and my tablet have SD card slots so no cables or adaptors. I think fast cf cards are needed if you are shooting raw video with magic lantern


----------



## Mt Spokane Photography (Dec 8, 2013)

Beware of SDXC cards, the speed is NOT what you might think it is.

There are gotchas when using SD cards.
1. The speeds avertised are for new blank cards, a regular format does not result in a new blank card. Once a memory sector in a SD card has been used, the camera must first erase it (a slow process) before writing to it. This makes the usable speed of the card drop to 10MB/sec, or in some cases to 20MB/sec. A time consuming low level format will restore the card speed for one more use.

2. Many cameras cannot take advantage of the claimed speed of the cards, and are limited to a slow speed.

With a CF card, you can do a regular format and get the full speed. Many users are misled by the claims of high SD card speeds, and some even believe they are getting them. I wish it were so.


----------



## Don Haines (Dec 9, 2013)

Mt Spokane Photography said:


> Beware of SDXC cards, the speed is NOT what you might think it is.
> 
> There are gotchas when using SD cards.
> 1. The speeds avertised are for new blank cards, a regular format does not result in a new blank card. Once a memory sector in a SD card has been used, the camera must first erase it (a slow process) before writing to it. This makes the usable speed of the card drop to 10MB/sec, or in some cases to 20MB/sec. A time consuming low level format will restore the card speed for one more use.
> ...


And beware the difference between write speed and read speed... The cards usually give you the read speed on the case but you have to dig bait for write speeds, which can be half the read speed or less...


----------



## dgatwood (Dec 11, 2013)

I think CompactFlash is pretty much dead at this point. 160 MB/sec. is the limit for CF unless they update the standard, and AFAIK, there's no indication that they're going to rev the standard again. Instead of updating the standard, they're replacing it with CFast, which is an entirely new standard that uses the same size card, but isn't backward-compatible with existing cards or forward-compatible with existing devices.

It's anybody's guess whether CFast will be a serious player going forward, or whether we'll just see that form factor dry up. (Yes, Canon has said that they're excited about it, blah, blah, but those are just words until actual devices that cost fewer than five figures start showing up from at least a handful of major manufacturers.)

Those 160 MB/sec. SanDisk cards are relatively slow compared to what's either available or about to be available in the SD world. Check out the Exceria Pro SDHC UHS-II series from Toshiba:

http://www.toshiba-memory.com/cms/en/products/sd-cards/exceria/exceria-pro.html

260 MB/sec. read, 240 MB/sec. write. They don't appear to be available in the U.S. yet (or at least I can't find them in any store), but at least in theory, they exist.


----------



## mackguyver (Dec 11, 2013)

The other key is WRITE speed. Lot's of the 90mb/s labeled cards don't write at half that speed. So it's great that the photos download to your PC faster, but the write speed in camera is most important. Always check the write speed before buying.


----------

