UHS-1 vs class 10 SD CARDS

According to the SD Association, these two standards have the same minimum write speed, which is all that defines SD standards. I have a class 10 SD card in my 7DII, and it takes much longer to write to it than to the CF card (ScanDisk Extrme 60MB/s). My question for those who have tried them is, are the 90-95MB/s UHS-1 cards actually that much above the minimum standard in terms of write performance? Or should I keep using the SD card as temporary overflow, between switching out CF cards?

Those speeds are usually the highest it can write it. Doesn't mean it will constantly write at that speeds but will spike to those speeds. Writing to CF cards will always be faster then SD.

Thanks. The SD Association states that advertised speeds are usually either read or write, and it is hard to tell which from the manufacturer's information. I have never had a camera that used SD before, and I was shocked at how long it takes to write four or five shots to SD. I think I will just keep writing to the CF card, and use SD for insurance when the CF card fills up.

pknight wrote in post #17587827
I have never had a camera that used SD before, and I was shocked at how long it takes to write four or five shots to SD.

Just how long do you think it takes and under what type of shooting conditions. It is possible there are other potential causes beyond being an SD card.

I read this before purchasing my last SDXC card.
http://www.cameramemor​yspeed.com/canon-70d/fastest-sd-cards/

Just to get a card capable of giving me the best performance.
Got a SanDisk Pro. Right now I'm limited by what the camera can handle.

Reading around, there was a post where SanDisk stated that Class 10 and UHS-1 are practically the same, as they both have the same minimum write speed (10MBps).

Oh and also read that CF cards do have an advantage over SD cards. Some CF cards have write acceleration built in, which helps clear the camera's buffer quicker, allowing for greater bursts.

John from PA wrote in post #17587865
Just how long do you think it takes and under what type of shooting conditions. It is possible there are other potential causes beyond being an SD card.

I doubt it. I am talking about taking bursts of shots, such as birds-in-flight. Given my shooting habits and style, I have never had to wait for the buffer to clear when using the CF card. When I have no CF card in, or it is full and the camera starts using the SD card, I get full buffers regularly. I know that you can fill up the buffer while saving to a CF card, but I don't. Shooting the same way with the SD leads to waiting for it to write on a regular basis.

vapore0n wrote in post #17588512
I read this before purchasing my last SDXC card.
http://www.cameramemor​yspeed.com/canon-70d/fastest-sd-cards/

Thanks. That is helpful

vapore0n wrote in post #17588512
Reading around, there was a post where SanDisk stated that Class 10 and UHS-1 are practically the same, as they both have the same minimum write speed (10MBps).

Yes. That is what the standard-keeper (SD Assoc.) says as well, but I am not really interested in minimum write speeds. My question was whether the higher speeds advertised for UHS-1 are indicators of real performance. If UHS-1 has higher maximum or average speeds than class-10, that would be important.

I did notice that the test you linked to recommended two UHS-3 cards. Page 511 of the 7DII manual states that UHS-1 cards are compatible, but does not mention UHS-3. Does anyone have experience with UHS-3 cards and the 7DII?

EDIT: The card test for the 7DII indicates that only UHS-1 cards are compatible: 7DII http://www.cameramemor​yspeed.com …st-sd-cf-card-comparison/

pknight wrote in post #17589153
I doubt it.

I guess I overstepped my bounds in trying to be helpful by asking just how long you think it takes. I fully realize CF cards are faster than an SD card. CF cards have a built in processor; SD cards rely on the processor in the camera to handle writing which slows things down. But FYI, I just fired off 10 images, RAW+jpeg, on a 60D with a known to be good class 10 card. The buffer light came on at about four to five images and cleared about 14 seconds after the start of the burst. Now, had you told me yours took 30 seconds, then we could ask some questions about your card. Counterfeit SD cards are quite common for instance.

John,

Sorry. I misunderstood your question. I didn't interpret it as a request for exact times. Mea culpa. My times are similar to what you describe. I don't think it is taking longer than it should, it is just that I had never used SD cards in a camera before, and had never had to wait for a card. The 7DII tests of cards on the site linked by vapore0n shows that some SD cards are faster than some CF cards (certainly faster than my old CF cards), and it does appear, from the data on that site, that there is a rough relationship between the advertised speeds and the test results. I should be able to avoid the type of write delays I am experiencing by getting one of the faster SD cards.

Thanks for your input.

I compared your numbers to my 60D with an El-cheapo Lexar Class 10. Using L-Raw+L-JPG, I got 7 shots before I hit the buffer, and it took 19s to clear. I don't consider that real-world usage, though. If I am shooting sports/action, and know I will be using AI-Servo and HS burst, I am shooting JPG. Using the same camera and card, I got a 48 second burst of 253 L-JPG shots before I hit the buffer. In real-life shooting, I rarely fire bursts of more than 5 or 6 shots. I have never hit the buffer in a real situation. Even a cheap class 10 should be good enough for lots of folks.

pknight wrote in post #17589169
I did notice that the test you linked to recommended two UHS-3 cards. Page 511 of the 7DII manual states that UHS-1 cards are compatible, but does not mention UHS-3. Does anyone have experience with UHS-3 cards and the 7DII?

EDIT: The card test for the 7DII indicates that only UHS-1 cards are compatible: 7DII http://www.cameramemor​yspeed.com …st-sd-cf-card-comparison/

The U3 card will work, just not at full potential.
You could save some money by going with the max the camera will take (U1).

I bought the U3 and worked on my 70D this past weekend. Ill compare my old SD (C10) and new (U3) see if it bottlenecks. I used my camera this past Sunday for volleyball and noticed I was buffering more than usual. I was shooting RAW+Jpeg though, which is not how I usually go.

GeoKras1989 wrote in post #17589918
. Even a cheap class 10 should be good enough for lots of folks.

No question about that. I always shoot raw, and my cheap class 10 card is not cutting it, but many people would have no problems.

pknight wrote in post #17590388
No question about that. I always shoot raw, and my cheap class 10 card is not cutting it, but many people would have no problems.

Understandable. Ten fps from a 7Dii way outstrips 5.6 from my 60D!

Here is the official definitely

UHS-1 simply means the SD interface has bandwidth of 104MB/s. It has "almost" no reference to the actual speed of the card. Most flash card today is write speed limited. So being UHS-1 card usually mean it can read up to about 95MB/s. There is always some differences between the theoretical bandwidth and the actual speed. 95 is about as fast as UHS-1 can ever rea.

The "almost" is this. In order to be certified as UHS-1 card, meaning with UHS-1 label, the card must be a Class10 card.

Class10 is a definitely for early video data format. It basically specific a set of data patterns, and Class10 card needs to read and write such patterns with at least 10MB/s. The Speed Class data pattern, contrary to what people believe, is NOT entirely sequential. To best describe it without going into too much detail, the pattern is a random set of sequential data. For example, random 4MBs of sequential data, meaning within each group of 4MB, data is sequential. But between each 4MB group, the data is random.

A Class10 notation has nothing to do with the sequential read and write limit of the card. A Sandisk Extreme Pro that can write at 90MB/s read at 95MB/s qualify for a Class10 card. But a Sandisk Ultra that read at 30MB/s and write at 12MB/s is still qualified as a Class10 card. So pay attention to the label on the package. Most manufacture will spell out sequential performance if it is significantly faster than 10MB/s. Also, pay attention to the wording. Transfer speed usually means read speed. If it is write speed, manufacture will usually spell it out.

Also, the correction notation is NOT UHS-3. The correct way is just U3. To be U3 card, it needs to have UHS-1 interface. It needs to have Class10 rating. On top of that, it needs to have pure sequential read/write performance of >30MB/s. So a U3 card is also a U1 card. As you can see, U3 requirement is well within UHS-1 interface speed. If you know your camera support UHS-1 interface, by all mean get U3 card. It will clear the buffer faster.