Extreme IV, UDMA CF card compatibility with 5D/40D?

I'm wondering if the newer cards work in the original 5D and 40D. Sizes like 8GB and 16GB, UDMA sandisk cards like the Extreme IV and other new designs. I don't want to buy them just to find out they don't work in the older cameras.

I believe the 5D uses fat32 for formatting - so any size card should work? Don't really know for sure though....

I know that UDMA cards are backward compatible. You won't see any speed benefit with the camera. Just faster downloads, if you have an UDMA capable card reader.

But there might be a size limitation. 8GB work fine in my 30D, which are the same vintage as 5D Classic. I would guess 16GB would be fine, too, but I don't know that for certain. There might be info on Canon's website... or Sandisk's or Lexar's sites.

I used an Extreme III and IV on my 5D. They work fine, but I found that I don't really need the speed.

Honestly, if you aren't using the full fps, I would say a cheap kingston would work just fine.

Also, purchasing a higher speed card doesn't always guarantee faster read/write times. If your camera can't write at the maximum speed, you'll never reach the card's potential. Just something to keep in mind.

+1 on what you've said here - nice summary.

Last year for one of the BF sales I picked up several of the 4GB Sandisk Ultra III cards...with rebate they all came to free. Certainly no increased "dump" speed from the camera that I can perceive, but they do upload to the PC much faster via the card reader.

S30L28 wrote in post #9087771
I used an Extreme III and IV on my 5D. They work fine, but I found that I don't really need the speed. .......

I'm not expecting faster write times from old cameras. I was just wondering if they were compatible.

I've used a UDMA card in my 40D with no problems.

More specificlly, I've used an ExtremeIV 8gb on my 40D fine.

Okay, and the 5D? It's an older camera.

16gig 400x UDMA cards work fine on the 5D. The Sandisk, all flavors, will also work. Don't know about 32gig since I don't use them.

Sandisk Extreme IV and Ducati cards are compatible and preferable on the 50D and 40D, since their speed clears the buffer far faster than slower cards when you do high speed continuous shooting such as birds in flight. As far as the latest UDMA Class 6 cards (Sandisk Extreme, Extreme Pro, Lexar Pro 600x, etc.), only the Canon 7D and 1D Mark IV can take advantage of their speed advantages over the Extreme IV series.