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Old Feb 2, 2010, 11:03 AM   #1
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Default Sandisk 8GB EXTREME III SDHC SD Card Class 6 - 20MB/s ou 30MB/s ???

Could someone tell me the difference between these 2 cards

What will 30Mb/s do better then 20 Mb/s will the difference only be on download transfer speed ( like from camera to pc) or will it also affect the burst speed rate

I`ve got a Canon 450d and i just want to make sure to get the full 3,5 fps rate in burst mode so will they both do the job
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Old Feb 2, 2010, 12:04 PM   #2
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The difference in speed is for both reading and writing. The new Extreme 30MB/s card is a Class 10 SDHC card, while the older 20MB/s card is just Class 6. The Class system was originally instituted to clarify the performance of a card while recording video, and Class 6 is all that's necessary (under optimal conditions.) But for continuous shooting of Large/Fine JPEGs or even RAW files, Class 10 is better.
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Old Feb 2, 2010, 5:39 PM   #3
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Hi TCav and guillermovilas,

I do not mean to hijack, but I also have a similar question in regards to the Sandisk Extreme III, so I thought I add on here instead of creating a new thread.

I currently own a GF1 and am looking for a second card (current card is the generic class 4 (I think) given free with the purchase) and have narrowed it down to the Sandisk Extreme III - although I am undecided on which speed.

The GF1 has a 3 fps rate in burst mode and goes for 4-7 RAW pics before slowing down (I am not sure what is the GF1 buffer size). If I go RAW + JPEG (highest settings) - is a class 6 20MB/s card is all I ever need or will the 30MB/s card serve me better?

To also take the advantage of the 30MB/s card, I would need a better card reader that goes up to ~ 30MB/s like the new Sandisk readers?

Thank you.

Justin.
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Old Feb 2, 2010, 9:04 PM   #4
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Justin,

The faster card will improve your burst speed, especially in jpeg+raw. So if burst is high on your agenda. A class 10 would be the way to go.

On the read speed of a card reader. IMHO waiting a extra min to download photos with a sdhc card read vs going with a high price read does not make sense to me. I have a cheapo 2 dollar ebay sdhc, and when I download 250 photos, the difference is about a minute, I have compared it with the high end card readers/writer I use at work. If downloading the photos to your computer is that much of a concern, then it is worth getting a faster reader. Hope that helps.
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Old Feb 3, 2010, 2:15 AM   #5
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The faster card will definately help with the continuous shooting performance if your GF1 can keep up with it!

When you fix one performance bottleneck, another one always appears. When you replace your Class 6 card with a Class 10 card, you may find that the transfer rate of your camera's buffer isn't fast enough to keep the card busy.

That is not to say that you shouldn't get a Class 10 card; you just may not see a proportional increase in performance.

And you can use any card reader with a Class 10 card; you just won't see the performance increase you paid for with the faster card. In fact, it's possible that your card reader might be the performance bottleneck when using your current Class 6 card.
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Old Feb 4, 2010, 2:32 AM   #6
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Thank you all It makes sense now.

Justin.
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