Camera Labs

Firstly, apologies if this has been covered elsewhere, but I searched through various posts (and the Canon website) on the tech specs of the 40D, and cannot find anything relating to the speed at which the camera writes image data out of the buffer to the CF card.
Basically I just want to know if there is a minimum spec. CF card required to allow the 40D to attain its max of 6.5fps?

Cheers.

Mostly it requires a fast memory card, and low compression and low noise reduction to get its max potential, something like the Sandisk Extreme III or the Lexar UDMA 300X should do the trick.

Hope this helps!

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That's great thanks - I was hoping that an Extreme III would suffice, just want to be sure

Hey IcyBlue,

I've been using the Lexar 4gb 300x and it works great. I shoot most of the time in RAW and it seems to write to the card quick. I tried shooting close to 40 continuous shots in jpeg without any delay. I'm quite happy with it.

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Roger,


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Don't forget that the 40D has a fairly generous buffer so my understanding is that the initial burst speed (6.5 fps high speed rate) is unaffected by the speed of the CF card. The best excuse (ahem, reason) I have heard for getting a really fast CF card is to speed up transfer of your photographs to the computer if you use a high speed card reader rather than the USB cable.

Bob.

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Kind of a echo of what Bob said,

Depending on your style of photography, the fastest of speed you can get may help a lot to you,

but the CF card's write speed affects the speed very little, sure a 300x card writes faster than a 60x card. If you need the max. fastest speed, the camera's settings affect it the most.

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Assistant News Photojournalist
Nikon and Canon Systems
A variety of f/2.8 lenses from 10.5 to 400mm
Support Cameralabs!

As ever, great replies guys - cheers!
I'm not that concerned about the xfer speed from card to PC (I'm more happy snapper than photo journo ), so given how inexpensive cards like the Extreme III are these days (£35 for 4GB from Camera World) I really have no inclination to spend more on even faster cards.

My understanding is that you take the maximum write speed of the card in mb/s and divide that by the image size in mb to find out how fast the buffer can be cleared. The 6.5fps will drop once your buffer is full.

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Graham
Flickr

That's correct. Just don't mix up Mb (=Mega Bit) and MB (=Mega Byte).
So a Class 6 SD(HC) card can transfer Data at min. 6MB/Sec. With a fine-jpeg size of 4MB that's only 1.5 pictures per second sustained tranfer rate.
And with RAW+jpeg you'll end up at 12-15MB per picture that means 0.5 pics/sec sustained transfer rate.
So to really keep the data flowing you should invest in some technology that goes to at least 20MB/sec

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
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