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Old Dec 16, 2009, 7:53 AM   #11
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compression of the files is a disadvantage of sdhc. One extra step to be handle before writing.
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Old Dec 16, 2009, 9:11 AM   #12
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The compression on SD Cards is for audio files only. For photos, there is no compression.

In fact, JPEG images are already compressed; trying to compress them again always makes them bigger.

So compression doesn't affect the use of SD/SDHC/SDXC cards in digital cameras.
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Old Dec 16, 2009, 4:36 PM   #13
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I still think the 50pin interface of the CF are faster then the faster sdhc. CF gives you a 16bit bus, while sdhc is a 4bit bus. That allows CF to have speeds of 300x or 45mb. Class 6 sdhc is 150x and 30 at best.
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Old Dec 16, 2009, 5:24 PM   #14
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Quote:
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I still think the 50pin interface of the CF are faster then the faster sdhc. CF gives you a 16bit bus, while sdhc is a 4bit bus. That allows CF to have speeds of 300x or 45mb. Class 6 sdhc is 150x and 30 at best.
I'm in the fortunate position that I can do a bit of a test on this as I have in my arsenal a Canon 1D mkIII which takes both CF and SDHD. I have Extreme III 30MB/s cards for both formats so set the camera to the highest ISO jpg making the file size large and then to 1/8000s and f8 so each shot is pure black and almost exactly the same size. In practise the resulting images ranged from 5.25mb to 5.48mb but it is pretty close.

Then shooting at 10fps I did a burst until the buffer was full so the continuous shooting stopped briefly and then timed how long it took to get everything to the card with both options.

I tried this 3 times in total with each card to ensure that there were no anomalies but only recorded the first set of data as the other 2 tests were almost identical and it's 11.15pm so I'm not being too pedantic.

With the CF card it took 35 photos which is 179MB and the time to save all to the card post last shot was 18.8 seconds.

With the SDHC card it took 37 photos which is 190MB and the time to save all to the card post last shot was 12.4 seconds.

From this test it would seem that the speed to save to a SDHC is quite a bit better.

It would be interesting if others have the ability to try other tests. Does anyone have the same level cards for both SD and CF and a multi card reader? Possibly timing how long it takes to upload 100MB to each card from the hard drive would be a good one...... or similar etc.

That's the end of me being remotely scientific for the evening. I can conclude that photographing a few hundred black shots isn't very creative.
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Old Dec 16, 2009, 5:32 PM   #15
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Very interesting. Thank you.
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Old Dec 16, 2009, 5:43 PM   #16
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We use allot of CF cards at work. They are 45mb cards, and the are fast for the purpose we need them for, most of our files that we upload onto them are 3gb.

Interesting test, did you do a high level format to both cards before running it. Where both card blank, so that the card can use the first available space and not have to move to the next. Or it may be that the sandisk extreme cf you used may need to be formatted, or that sandisk makes a better sdhc then a cf.

But I know one of the guys put one of our 45mb card in his camera to play around, and his comment was he wants to take on of the 8gb cf card home for personal use. I have multi card reader, but only have a 30mb sdhc and 45mb cf. That would not be a fair test.
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Old Dec 16, 2009, 5:50 PM   #17
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Mark1616

If you want a super fast card for you canon. There will be a 600x CF coming out. I sure it will be price to match though.
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Old Dec 16, 2009, 5:55 PM   #18
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I had some images already on the cards but nothing too bad. I've just formatted and run this again and it did take a couple of seconds off of the CF card but still not as fast as the SDHC which was again faster and took 2 more photos.

I'm happy with the speeds I'm getting with these as I no longer shoot sports that much and I've never been into machine gunning so the buffer always has space.

I'm sure the new Canon 1D mkIV will like the extra speed though.
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Old Dec 16, 2009, 5:59 PM   #19
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So what do you think about the new class 10 cards?
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Old Dec 16, 2009, 5:59 PM   #20
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Quote:
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We use allot of CF cards at work. They are 45mb cards, and the are fast for the purpose we need them for, most of our files that we upload onto them are 3gb.
What sort of work are you doing to create these sort of files, sounds interesting?
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