Canon D7 - CF Memory Card

[essaytee]

But it doesn't mean very much. What you need to know is how it will work with your camera. Marketing blurb can be taken as a general indication, but not much more than that - and sometimes not even that.

Since you don't seem to have found the right pages, I had a look for you. Have a look at this.

http://www.robgalbraith.com/bins/con...=7-10044-10297

I think Kym may already have posted this, but just to be sure you read it ...

It means what it means, in theory. The theory is correct. I thought it was a 'given' that obviously the ultimate transfer (write) speed would depend upon the device writing the data, in this case a camera. I'm sure that was pointed out earlier in the thread.

[JorgD]

A similar question about CF speeds was asked before, and here was my response to the question 7 weeks ago, which I think still applies to the current question.

I use an Extreme III card rated at 30 MB/sec and and Extreme card rated at 60 MB /sec. When I got the Extreme card, I wanted to see how much faster it really is compared to the Extreme III card, so I ran some tests at my PC with my USB card reader. The 30 MB/sec card was faster than the 60 MB/sec card.

This result was of course slightly disappointing, so I started doing more research on this, starting on the Sandisk web page. It appears as they their wording and testing procedures changed over time. The Extreme III card has a through put of at least 30 MB/sec, the Extreme card has a throughput of up to 60 MB/sec. Looks like the words "at least" and "up to" actually cross over for me.

Doing further research, the 60 MB/sec card uses an UDMA interface rather than the PIO interface of the older cards. Now, unless your card reader can make full use of UDMA (which mine obviously could not), you will end up with no better and possibly worse performance than the older cards.

Testing both cards in my 7D shooting Raw images, both cards allowed 22 shots to be taken at high speed before the camera started to slow down. The stated buffer for the 7D is 15 raw. So from the cameras perspective there was no difference at all. Even shooting 1080p movie mode with the 7D, provided your card can accept at least 8 MB/sec, you will have no problem taking movies to your hearts content.

I recently purchased a Nexto Extreme external HD with card reader, and the Nexto could back up the images significantly faster from the 60 MB/sec card than the 30 MB/sec card, causing me to believe that it does make good use of the UDMA interface.

I personally would not spend a lot of money on a faster card as the camera can't make use of the faster speed and the USB 2.0 interface is also slower than most cards so you won't see any benefit there. The only time there is a benefit for higher card speed is if you have a UDMA enabled backup device like a Nexto, or if you have a UDMA CF card reader connected to Firewire 800 or USB 3 when it is released.

[Steve Axford]

It means what it means, in theory. The theory is correct. I thought it was a 'given' that obviously the ultimate transfer (write) speed would depend upon the device writing the data, in this case a camera. I'm sure that was pointed out earlier in the thread.

Not true. The write speed is dependant on both the camera AND the device it is writing to. It's a shame that there is so much fud going around.

[Clubmanmc]

A similar question about CF speeds was asked before, and here was my response to the question 7 weeks ago, which I think still applies to the current question.

I use an Extreme III card rated at 30 MB/sec and and Extreme card rated at 60 MB /sec. When I got the Extreme card, I wanted to see how much faster it really is compared to the Extreme III card, so I ran some tests at my PC with my USB card reader. The 30 MB/sec card was faster than the 60 MB/sec card.

This result was of course slightly disappointing, so I started doing more research on this, starting on the Sandisk web page. It appears as they their wording and testing procedures changed over time. The Extreme III card has a through put of at least 30 MB/sec, the Extreme card has a throughput of up to 60 MB/sec. Looks like the words "at least" and "up to" actually cross over for me.

Doing further research, the 60 MB/sec card uses an UDMA interface rather than the PIO interface of the older cards. Now, unless your card reader can make full use of UDMA (which mine obviously could not), you will end up with no better and possibly worse performance than the older cards.

Testing both cards in my 7D shooting Raw images, both cards allowed 22 shots to be taken at high speed before the camera started to slow down. The stated buffer for the 7D is 15 raw. So from the cameras perspective there was no difference at all. Even shooting 1080p movie mode with the 7D, provided your card can accept at least 8 MB/sec, you will have no problem taking movies to your hearts content.

I recently purchased a Nexto Extreme external HD with card reader, and the Nexto could back up the images significantly faster from the 60 MB/sec card than the 30 MB/sec card, causing me to believe that it does make good use of the UDMA interface.

I personally would not spend a lot of money on a faster card as the camera can't make use of the faster speed and the USB 2.0 interface is also slower than most cards so you won't see any benefit there. The only time there is a benefit for higher card speed is if you have a UDMA enabled backup device like a Nexto, or if you have a UDMA CF card reader connected to Firewire 800 or USB 3 when it is released.

I have seen the same results, a fire wire CF reader will get you a little faster... but at the price... its best to get the reader going and go get a cup of coffee...

M

[mkooper]

Thank you to all involved in this discussion. It has cleared up a lot of questions for me. I also use successive rapid bursts of shots in RAW + JPG for exhibition and performance dancing routines and have found that slow cards mean longer periods between bursts. However it is good to find that I don't have to spend $$ on the latest and greatest to get the best results.

--> Here <-- are some examples as to why you would take rapid succession of photos in order to give the customer the best possible result for their money