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Old Apr 13, 2006, 1:03 AM   #1
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I don't know why do we need high speed memory card for digital camera? Actually, it's not necessary for other devices and we can't distinguish the differences of speed.

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Old Apr 13, 2006, 3:03 AM   #2
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I'm going to take a guess and say the need for a high speed card in digital camers is present due to the fact that in a fraction of a second (literally), a file size of anywhere from a couple to over a dozen megabytes is created. The camera's buffer can only hold a certain amount of data before it needs to be written to the card therefore the faster the card you have, the faster that buffer will empty and subsequently, the faster you can take pictures.
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Old Apr 13, 2006, 5:56 AM   #3
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Justin Hancock wrote:
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I'm going to take a guess and say the need for a high speed card in digital camers is present due to the fact that in a fraction of a second (literally), a file size of anywhere from a couple to over a dozen megabytes is created. The camera's buffer can only hold a certain amount of data before it needs to be written to the card therefore the faster the card you have, the faster that buffer will empty and subsequently, the faster you can take pictures.

Exactly. My D70 can take 4 frames at 3 frames per second. After that it slows down how much it slows down depends on the speed of the memory card. After the first few shots the speed of the memory card directly affects the speed of capture in continous mode but it can also affect the speed at which I can get the next shot in single frame mode. The speed of the card can mean the difference between capturuing a shot and missing it.
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Old Apr 13, 2006, 7:55 AM   #4
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my fz30 takes about 7sec to store a 8mp raw file on my crappy old sd card. on my 40x it takes about 2-3sec. So big differnece in speed.



Very neccessary if you shoot in raw with a higher resolution.

In jpeg i would say the differnce is marginal but for formating and accessing its a hige difference

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Old Apr 13, 2006, 11:14 AM   #5
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It all depends on the camera. Some models won't be able to take advantage of faster cards, because the camera's interface to media is the bottleneck.

But, a lot of models can take advantage of faster cards.

For example, using a Sandisk Extreme III card, my Konica Minolta Maxxum 5D can write to media at approximately 8.8MB/second. That means it can write one raw file per second to the memory card *after* the camera's internal buffer is full (and this model only has a 5 shot buffer if you are shooting in raw).

Using a slow CompactFlash card, this camera may take over 9 seconds per raw file to save them to media. These files are very large, and unless you want to wait on the camera if you need to take more than 5 raw photos quickly before a long pause, a fast card is a good idea. ;-)

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Old Apr 13, 2006, 12:21 PM   #6
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It definitely depends on the camera. Some cameras have their own built in memory - a buffer.

This isn't used to store images in the way you do on a memory card. It's used to store images while they wait their turn to be written to the memory card. Once they've all been written to the card the buffer is free again for the next image.

This buffer memory is usually very high speed memory. The size of the buffer will determine how much you will need a fast memory card. If the camera has a large buffer (able to store perhaps 5 images), you might not notice the effect of a fast memory card.

If there is no buffer, then the speed of the card itselfmakes a huge difference.

In general terms, SLRs have a reasonable buffer. Compact cameras don't have any.
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