write speed for 10 FPS?

photodoc63 said:

I am about to purchase the 7D Mark2. Is there a minimum write speed on the memory card that is required to satisfy the 10 FPS capability? I know some cards list a speed that is "possible" but not necessarily "sustainable" however, I am not sure that refers to the write or read speed. Also, when a card lists a single speed of say 15MB/s is that the write or read speed? Thanks.

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You probably want to get the fastest card possible within your budget. I use 64GB CompactFlash Memory Card Ultimate 1000x UDMA.

some discussions :

http://www.dpreview.com/forums/post/55191037 and http://www.dpreview.com/forums/post/55089392

I settled for a CF card with x800 speed rating.

You are most concerned about the write speed of the card. If you do your purchasing homework, you can find out the specs on just about any worthwhile card for writing and for reading. If the specs are completely hidden, then just move on to the next brand of card.

Also keep in mind that some cameras have two memory card slots, and some users will activate them both. The write speed to the faster card will be slowed down to the write speed of the slower card.

Shooting RAW, 10fps is achieved only until the buffer fills, 2-3 seconds. No card will allow you to write at 10fps RAW indefinitely. A faster card only will allow you to squeeze a few extra shots before slowing down, and then increase the (reduced) fps as the speed is throttled by the card speed.

From http://www.cameramemoryspeed.com/canon-7d-mark-ii/fastest-sd-cf-card-comparison/ ,

The fastest cards will allow 28 shots at 10fps, the slowest only 20. A decent card will get 23-25. After the buffer is full, the best you'll see is 3.5fps. While the worst card test was a fraction of an fps, a moderately priced solution will allow 2-3 fps continuously.

The question to ask yourself is how long you actually need to squeeze off 25-30+ shots.

photodoc63 said:

I am about to purchase the 7D Mark2. Is there a minimum write speed on the memory card that is required to satisfy the 10 FPS capability? I know some cards list a speed that is "possible" but not necessarily "sustainable" however, I am not sure that refers to the write or read speed. Also, when a card lists a single speed of say 15MB/s is that the write or read speed? Thanks.

Click to expand...

The 7D2 is 20 megapixel with top speed of 10 fps. I am shooting a 1DX which is 18 megapixel and 12 fps. The amount of data that needs to be flushed is probably a similar amount when firing a long burst with either of these cameras.

If I shoot a long burst with a 400x Transcend CF card, I notice a slowdown after a couple seconds. With a Lexar 1000x card, the camera does not hesitate at all.

EDIT: I just checked and found a lo of inconsistencies in the 'write speed' ratings of various cards. The Lexar 1000x card I mentioned is no longer available but it was rated for 95MB/sec write speed. The Transcend 400x cards I have are rated at 40MB/sec write speed. But some newer 800x cards are only rated at 45MB/sec write speed, which is only slightly faster than the 400x Transcend cards that I have.

So to rephrase what I had written earlier and have now deleted, I would instead look for cards with a rated write speed of at least 80MB/sec, and disregard the 400x, 800x or 1066x labels that they put on the cards. Those numbers appear to be somewhat irrelevant and are not necessarily an indication of the write speed of the card.

I don't shoot long bursts very often, but if or when I do, I do not want the memory card to be the limiting factor. If you purchase a camera that can shoot that fast, there is no sense in canceling that feature by using a card that is not able to keep up with the top speed of the camera.

Good luck, and enjoy the camera.

--
My latest project (Alaska): http://www.pbase.com/tim32225/alaska_2013
Photoblog at: http://timrucciphotography.blogspot.com/
Gallery at: http://www.timrucci.com

I did not see anyone say which card they were talking about CF or SD. I use a 32g Sandisk 160mb/s CF card along with a 32g Sandisk 95 mb/s USH1 SD card. DO NOT get the USH2 sd cards the 7D2 does not support faster then USH1, the card will default back to the classic 1-10 speed rating. Take a look at the 2 USH2 cards on the link above

Dave

rdspear said:

Shooting RAW, 10fps is achieved only until the buffer fills, 2-3 seconds. No card will allow you to write at 10fps RAW indefinitely. A faster card only will allow you to squeeze a few extra shots before slowing down, and then increase the (reduced) fps as the speed is throttled by the card speed.

From http://www.cameramemoryspeed.com/canon-7d-mark-ii/fastest-sd-cf-card-comparison/ ,

The fastest cards will allow 28 shots at 10fps, the slowest only 20. A decent card will get 23-25. After the buffer is full, the best you'll see is 3.5fps. While the worst card test was a fraction of an fps, a moderately priced solution will allow 2-3 fps continuously.

The question to ask yourself is how long you actually need to squeeze off 25-30+ shots.

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In most shooting situations, you'll actually get better results than that test. As they say in the test write-up, they used a very detailed test scene that produced RAW files of about 30MB. With smaller files, which you would get from less detailed scenes (think a sharp subject against a blurred background, such as you get in a lot of sports or wildlife), you can get more shots, before the buffer fills, and maintain a higher speed after that. I have read reports of getting over 40 shots in a 10fps burst, and then maintaining over 5fps after that. I haven't tested it myself. I don't think I've ever taken more than about 20 shots in a burst. I do use a pretty high speed CF card. My SD card is only a moderate speed, but I have the camera set to write to the CF, and only switch, if it fills up (or I remove it).

Thank you, Tim, and the rest of the responders. The info was very helpful. Off I go to B+H.

Rick

Bobby49 said:

I settled for a CF card with x800 speed rating.

You are most concerned about the write speed of the card. If you do your purchasing homework, you can find out the specs on just about any worthwhile card for writing and for reading. If the specs are completely hidden, then just move on to the next brand of card.

Also keep in mind that some cameras have two memory card slots, and some users will activate them both. The write speed to the faster card will be slowed down to the write speed of the slower card.

Click to expand...

So did I; for my shooting I can't imagine a need for 31 of the almost exact same shot. For others, this is a critical requirement.

I have Lexar Pros 800 CF and a 600 SD. I write RAW to the CF and jpg as backup to the SD and consistently get 20-22 of real shots (none of this lens cap on, theoretical maximum silliness) before the buffer fills. This is more than enough for my needs. I haven't tested just the RAW to CF only (with no write to SD), which I'm guessing will get me to 25 or so. IF (big if for me) I ever feel that this limits me, I'll get a single screaming fast CF, which should boost me to 30+ before the buffer fills. ymmv

Cheers,

GT

10 fps is 200MB/s if you are shooting RAW. I have have an 800x Transcend CF and it's good for 30 shots before the buffer fills.

If if you pay top dollar for a 1066x card it allegedly can keep up the write speed of the buffer.

If you switch to JPGS then it will keep going until the card is full or the battery runs out even at 800x....