Well, as "poster boy" for SanDisk, need I say more?
shot tens of thousands of frames in my Canon Mark IIs all over the world,
in all sorts of extreme conditions using San Disk Ultra II and Extreme III
cards...they have worked flawlessly. I highly recommend them.
Back in my Nikon days, I shot Delkin Pro cards, they were reliable and trouble free too.
Both Delkin and SanDisk are great companies and they stand behind their products...Lexar of course is another big player...although I cannot speak from experience, having never used their products, a lot of professionals use their cards and get great results.
How much CF should you carry? Well even on my longest, most intense shooting days I rarely burn through more than about 4 gigs....that's usually if I'm "machine gunning" stuff, to make sure I capture the exact moment of an expression or event. During my coverage of the tsunami, I shot from sun up to sun down and beyond and never shot more than 4 gigs. In my bag I carry a total of about 15 gigs of CF, primarily because if I have no way to download images, I can shoot for about 4 days. If I know I will be out longer than 4 days without the ability to download images to my computer, then I adjust my Canon Mark IIs to a smaller file size and can easily double the number images I am able to shoot. With higher compression (smaller file size) I have never lost the ability to sell the images.
The Canon Mark II has an additional slot for SD cards, so I also have a pair of 1 gig SanDisk Extreme III SD cards in my cameras, as "backups", but rarely end up using them. SD cards seem to be a bit less convenient for me in terms of downloading, since they do not fit in my Cardbus 32 PC slot CF Card adapter, and they feel a bit fragile and their diminutive size makes them easier to lose as compared to the thicker, more sturdy CF. Maybe some day all professional digital SLRs will go to SD cards and this will be a moot point. In a digital world things change fast, so don't fight it, enjoy the ride, it just gets better, faster, smaller all the time !
how I store my CF cards click here
Just a new bit of info from Canon.....
January 26, 2006 Product Support &Market Education Department
Canon Tech Bulletin TB 012606 SD card capacities Maximum SD card size: 2GB EOS-1D Mark II N Digital SLR While all versions of the EOS-1D Mark II series (including EOS-1Ds Mark II) have been able to routinely work with large-capacity CompactFlash cards, there is an issue with the smaller SD type memory cards affecting all of these cameras.
SD memory cards larger than 2GB WILL NOT work in any EOS-1D series camera. This includes the recently introduced 4GB SD cards that are now coming onto the market. The basic reason for this is that among SD card manufacturers, there is industry-wide standardization on how data is accessed on cards 2GB and smaller. However, for whatever reason(s), this has not happened (to date) with SD cards larger than 2GB. And apparently, there are differences in how the data is accessed on these cards. This can cause irregular operation.
Some additional points for Canon staff, dealer sales people, and end-users to be aware of: Current EOS digital SLRs EOS 5D, EOS-1Ds Mark II, EOS-1D Mark II N (and EOS-1D Mark II), EOS 20D, and Digital Rebel XT have been tested with CompactFlash cards of 6GB and 8GB sizes, and these have performed without problems. SD cards up to 2GB in size have worked reliably. However, as stated above, SD cards of 4GB will not work, as of January 2006.
January 26, 2006 Product Support &Market Education Department!