Compatibility of UDMA Memory Cards --

<p >I have a 30D and I know it will not support UDMA, but I was told that a UDMA compact flash card would work in the 30D, but at the slower speeds. </p>

<p > </p>

<p >The same person also said that a UDMA card would work in a non-UDMA card reader, but again it would be slow. </p>

<p > </p>

<p >Has someone tried a UDMA card in a non-UDMA camera and will it work? </p>

<p > </p>

<p >Jim</p>

<p>If the camera isn't UMDA compatible, it simply ignores the UDMA capability of the card. Ditto for card readers</p>

<p>I don't think this makes the card slower than a similar non-UDMA card, it just won't read/write as fast as it would if the camera supported UDMA. I've used UDMA cards in my 40D and they are fine.</p>

<p>Is the 40D UDMA capable? I know the 50D is; not sure about the 40.</p>

<p >Bob --</p>

<p > </p>

<p >I was hoping the UDMA cards were backward compatible. Sandisk has a good price on 8G cards and I was going to invest in the UDMA card so I would be ready if I get a 50D or 5D. </p>

<p > </p>

<p >We all like to dream.</p>

<p > </p>

<p >Thanks,</p>

<p > </p>

<p >Jim</p>

<p>The UDMA cards are backwards compatible. As I said, if the camera doesn't have UDMA capability, it just ignores the UDMA features of the card. UDMA CF cards should work in any Compact Flash card application.</p>

<p>The 40D is not UDMA compatible, but the 50D is.</p>

<p>Compatibility matters with SDHC cards, which are not backwards compatible with cameras that are designed only for SD cards. You can use an SD card in an SDHC camera, but you can't use an SDHC card in an SD camera.</p>

<p>the bigger question is why you want them - extreme 3 has the same rebate program going and with the exception of the 1D3 and 1Ds3 there are no Canons that really take advantage. Even the 5DII only gives a 1 frame burst bonus (meaing that with extreme 3 it gets off about 13 raw before slowing and 14 with extreme 4 in my non scientific test) with no problemes in video capture either.<br>

The only time I can see putting the money into extreme 4 or other UDMA cards is if you are shooting giant amounts of images and are going to use a UDMA card reader and save yourself a little bit of time....</p>

<p >JC</p>

<p > </p>

<p >Looking at the spec. on the 5DII -- </p>

<p >" JPEG = 78 Frames ( 310 with UFMA card)" </p>

<p >"RAW : 13 frames"</p>

<p >Are you saying you tested and only got a one frame improvement in RAW?</p>

<p > </p>

<p >Jim</p>

<p>I find I can shoot about 17 to 18 raw in a burst. Using 50D with Transcend UDMA 8gb 300X card. Additionaly it finishes writing all images in about 2 seconds after completing the last shot. With an non UDMA card it seems to take forever to write a burst like this. I find the UDMA USB 2.0 card readers download to my compouter using Mac OS X 10.5.6 about twice as fast a a firewire non UDMA card reader. Additionall the UDMA reader downloads non UDMA cards about twice as fast as well.<br>

My advice would be if you eventually plan to upgrade to a camera that will support UDMA you might as buy the UDMA cards and reader now. BTW I bought the Omniflash UDMA card reader on eBay for about $20 and it has worked flawlessly for me.</p>

<p>SD (Secure Digital) uses FAT16 file system, max is 4GB. It is software problem<br>

HDSD (High Capacity Secure Digital) uses FAT32 file system, lots of GB but max file size is 4BGB (that is why only xx minutes of video)<br>

If firmware of the device (camera or reader) only knows FAT16 then it can not read FAT32 (in some cases you can format a 8GB card with FAT16 file system but with an increased cluster size so you have 8GB available, eg. my IXUS 860)<br>

UDMA is a hardware option, usually devices negotiate, and use the max speed or the slower one, that is why new devices are "backward compatibles".</p>

<p>Addendum: I meant IXUS 860 was able to use 8GB card, the format action was done in a PC from the command line</p>