Rebel Xt - Does it use Write Acceleration?

cwphotos

I know the 300d didnt so I was wondering if the Xt does. I need a new CF card but I dont wanna spend the extra cash if it cant use it.

Thanks. :dunno

cmason

cwphotos wrote:

I know the 300d didnt so I was wondering if the Xt does. I need a new CF card but I dont wanna spend the extra cash if it cant use it.

Thanks.

not sure what you mean by "write acceleration". But here is a test done with lots of different CF cards and the XT...interesting results.... I chose a SanDisk Ultra II based on this info for my XT.

If you are asking whether the XT can benefit from fast CF cards = yes, esp if you are shooting JPEG+RAW.

cwphotos

Thanks. Thats the answer I was looking for. Ill by another sandisk ultra 2 then. They seem to be of a good build quality.

HeldDown

IIRC, the Digic2 chip writes at (approx) 45x. Therefore, anything there or above is not going to effect your write speed. Don't waste money on an 80x or 100x card; I use a 50x and a 60x to great effect. Good luck!

ian408

HeldDown wrote:

IIRC, the Digic2 chip writes at (approx) 45x. Therefore, anything there or above is not going to effect your write speed. Don't waste money on an 80x or 100x card; I use a 50x and a 60x to great effect. Good luck!

I'll offer a slightly different opinion. By the way, this is not bad advice--my
thoughts are just slightly different.

Putting it in my context, if you only shoot landscapes and never have a need
for that extra speed, don't buy it. In fact, you might be able to use any
inexpensive card so long as it's reliable--regardless of what body you put it
into. However, if you shoot sports with a 20d and know you will upgrade to
a 1dmkII, then getting an X-speed card might make sense.

Ian

cmason

ian408 wrote:

In fact, you might be able to use any
inexpensive card so long as it's reliable--regardless of what body you put it
into.

Agree with this...if you take a JPEG+RAW shot, which would be about 12MB+ or so in total file size (8.3MB for RAW and 3.3 for JPEG Fine). The cheapest CF card in Rob Galbraith's test wrote at about 1MB/sec, therefore if you don't take pictures faster that 12 secs apart, you can live with the slowest. But if you do take a few in bursts (say sports or maybe a bird flying), you may hit the limits of the card quickly.

erich6

Here's a link to a card speed test database:

http://www.robgalbraith.com/bins/multi_page.asp?cid=6007

cabbey

You might find this write up from Bob Atkins handy as well. Net is that Canon doesn't support Lexar's "Write Accelleration" gimicks.

colourbox

I've been using the Sandisk Ultra II in my XT after a) it did well in the Rob Galbraith CF card comparison linked previously, and b) they started turning up at my local Costco for about the same price as it was online, and without the freight wait.

David_S85

Agreed that cards can be written to in-cam no faster than a certain speed. But what about when the card is out of the camera and uploading to a computer or other storage device? Would a 80x or faster card perform better in that regard?

cmason

David_S85 wrote:

Agreed that cards can be written to in-cam no faster than a certain speed. But what about when the card is out of the camera and uploading to a computer or other storage device? Would a 80x or faster card perform better in that regard?

I am no expert, but I would not think that the write speed of the card has much to do with transferring files. Writing is a process of physically changing the memory core, reading is simply "observing" that state. In transferring, you have to worry about the interface of the CF card but also your USB/Firewire speed, since most card readers (even internal ones) transfer over USB. USB 1.1 had a speed of 12mbps, while USB 2 has speed up to 480mbps (firewire is 400mbps). USB 1.1 will be dramatically slower of course.

SanDisk says their Ultra II 1GB CF card reads at 10 MB/sec (writes at 9MB/sec). Since 1MB=8mb, this translates to a read speed of 800mbps, meaning that USB 2 or Firewire would be the bottleneck. Standard CFs read about 4-5MB/sec (320-480mbps), so in this case, you may be a bit slower in transfer with a standard card.

Btw, SanDisk says their Extreme series of cards reads/writes at 20MB/sec, and I think your original question would come into play at this point, as it is likely that this CF card exceeds the write speed of the camera, and the read speed of the USB/Firewire by such a large margin that you may not see a huge leap in benefit.

ziggy53

David_S85 wrote:

Agreed that cards can be written to in-cam no faster than a certain speed. But what about when the card is out of the camera and uploading to a computer or other storage device? Would a 80x or faster card perform better in that regard?

David,

If you use a USB 2.x HiSpeed device (reader), I believe it should speed things up. I haven't seen any direct evidence, in the form of a controlled test, but it makes sense according to the transfer speeds involved and the connection speeds of the different forms of USB.

Another thing I believe to be true, when stressed, as in "burst" captures, the faster speed cards seem to run cooler than the slower cards. This could yield benefits to the card and its host device beyond the speed benefits.

ziggy53