Sorry, but your question is really confusing. The adapter will let you use SMC card, where only XD is supported, and the capacity of the card won't make any difference at all. Also, what is the type of 512mb card? And what is the type of the 2GB card you're planning to buy? Anyway, try checking out
http://www.memory.co.uk . It has loads of information about different types of cards and formats, also it has information about the adapters, so it might be really helpful for you. Sorry if I misunderstood you, and I hope my explanation was at least a little bit helpful. Good luck
