Memory cards have limits, something that surprised me when I first learn of the problem. The SD memory card's specification limits it to 2GB. The original Sony MemoryStick was limited to 128MB!
With memory prices crashing, and memory demands increasing, the bodies behind these standards had to up the limits. That's why there is a confusing array of MemoryStick models from Sony: Duo, M2, and so on. And that's why I recommend to friends they not buy Sony digital cameras.
On the SD side, the standards body came up with SDHC (secure digital high capacity), which allows for 4GB and larger SD memory cards. Fine, except that most SD-using devices don't understand SDHC.
I bought a 4GB SDHC card from FutureShop, after the Canadian electronics firm has it on sale for CDN$100 (about US$86), with free SD/SDHC card reader thrown in. I wanted it for two reasons:
1. For the SanDisk V-mate digital video recorder (2GB cards can record only 1.5 hours, and most of my home video tapes are 2 hours).
2. To try out the SDHC card in SD devices.
It didn't take long for me to find that SanDisk's warning label was correct: "THIS CARD IS COMPATIBLE WITH SDHC DEVICES ONLY." Here's the result of my testing:
* Palm T|X -- insisted no memory card was installed. I've read that Palm made an SDHC patch for Treos, so it would be nice if such one existed for the T|X.
* Samsung NV3 digital camera -- acknowledged the card, but reported there was room for 0 pictures.
* Non-SDHC generic brand USB v2.0 card reader -- the read/write light glowed steady red, but Windows 2000 complained, "Please insert a disk into drive L:". Even after I removed the SDHC card, the read/write light continued to glow red. Is it possible to lock up a card reader?
* SD card reader built into my Compaq notebook computer -- Windows XP did not acknowledge its existence.
I'll update this list when I get a chance to try my dad's newish Canon digital camera, my daughter's newish Samsung digital camera, and my other daughter's oldish Casio camera.