Yes, you need micro to mini SD adapter to use with N810.

To add another source, I purchased 8GB Sandisk microSDHC card with full-SD adapter and micromate reader from eBay. These "three in one" packages sell now about $60 including shipping. The micromate reader is very small and proved very fast! I clocked 13.5MB/s write speed (using 700MB avi file) to that Sandisk 8GB microSDHC (class 4) card using PC computer. Doesn't that mean that the card is actually class 13.5?

I also purchased separate microSD to miniSD adapter from eBay too. Brand was Topram and it works fine on my N810. (Didn't Sandisks' own micro to mini adapters have problems?) Total cost including shipping below $5.

For comparison, Newegg sells the same 8GB card $85 with shipping and it doesn't come with SD adapter nor reader!