I've found this great deal on an 8GB CF card. It's an 75x card by Transcend. Is 75x fast enough? I'm using a generic "brand-less" card I got off eBay (said to be 133x, but I've never really tested it). I was lucky that it was noticeably faster than the standard Sandisk cards (not ULTRA or Extreme, the blue-labeled ones), and other cards I borrowed off somebody. The biggest thing I've noticed is that a faster card really empties the burst-buffer significantly. Now that I have a 40D, it's increasingly more important that I have a card that can write quickly. Is 80x a decent speed? I know some pro-cards go up to 300x, but this 75x card is a really great deal. 75x is around $90, and 266x is around $160 (Canadian dollars).
120x Cards are said to be around 21mbp/s So we can assume that 1x = 0.175 mbp/s multiply that by 75 and we get 13.125mbp/s Sandisk Extreme III's by comparison (which seem to be the current favourite for most bit-techers as the 2GB's are pretty cheap in the UK) supposedly have a minimum of 20mbp/s transfer and the Extreme IV does "up to 40mbp/s. Why nobody standardises their speeds I will never know. I would suggest that the card is perhaps a little slow, though unless you are doing lots of sequential shots you may never notice. Personally though I would always buy the best card I could afford even if its smaller than the cheaper equivalent just due to reliablility, that and smaller cards are often a good thing. Just imagine if you lost 8GB of data in one hit and it was your holiday/wedding photos. I'd always take a handful of 2GB's or a couple of 4GB's for that reason alone. Hopefully someone with a little more knowledge of CF transfer speeds can help me out here though. ::edit:: According to wiki
That's a very nice price for an 8GByte card but its not very fast - a 40D should be able to benefit from a faster card. I find the main advantage of faster cards is when you want to preview images on the camera screen when lighting is difficult. Having to wait on a slow card is annoying. Best palce to check flash card performane is the robgalbraith site, not got a 40D in the database but figures for the 30D are there. http://www.robgalbraith.com/bins/multi_page.asp?cid=6007-8478
I think you'll be more than fine with that, unless you've got something like the 10FPS 1DsMkIII. The 40D is 6.5FPS I think, right? I shoot with a 50x card and have never found it being problematic for rapidfire shots, and though my 400D only does 3FPS, I think I can still take 15-20 RAW shots before it starts to slow down from a full buffer. From what I hear, often times the interface between the camera and the card is going to be the limiting factor, rather than the speed of the card itself.
