Steve's Digicams Forums

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-   -   Does transfer speed matter with a DSLR? (

ron519098 Oct 24, 2007 5:06 AM

I've a few high speed SD cards which I use with my compact cameras with the speed rating of such cardsbeing quite important for using the movie mode in such cameras at its highest frame rate.

Question is, does it really matter when it comes to my DSLR? Even in continuous shooting mode the camera's buffer memory is going to handle most situations isn't it? Or am I being simplistic here?

Edit: Actually I guess I should be talking about write speed here, but it all boils down to the ability to transfer data from the camera's processor to the SD card at an acceptable speed.

JimC Oct 24, 2007 6:40 AM

That depends on the camera model, how large it's buffer is, and what it's write speed to media is.

Most newer dSLR models will benefit from a fast card after their buffer becomes full (then, you'll get a faster "buffer full" rate if you need to shoot with a full buffer, and you will flush the full buffer to media faster).

It all depends on what you want to shoot and what image type you use, too. If you're shooting raw, you'll probably fill up the cameras internal buffer much faster if you want to shoot in continuous mode, and the write speed to media can become more important unless you want to wait on the camera.

It looks like you're probably using a D80. It's got a buffer of around 6 or 7 frames shooting raw. Then it will slow down to around 1 second per shot until you flush the buffer with a fast card like an Extreme III.

Steve has some speed tests here using a 1GB Extreme III (but, a slower card will increase shot to shot times with a full buffer and will also increase the time it takes to flush a full buffer to the card.

Rob Galbraith has some speed tests of some of the popular cards in it here so you can see the speed the camera is capable of writing to different cards:

ron519098 Oct 24, 2007 7:07 AM

Thanks Jim.

I can see I was being very simplistic!!

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