32GB. You absolutely want the fastest you can, because that governs the time between pictures. You want at least Class 10, and you want to go faster than that if you can. RAW pix are about 18MB each, so with a 32G card, you get ~1100 or 1200 pictures.
By Chris Marlowe on December 9, 2014
When you download the pictures into Lightroom or other photo software, there will a Leica file number that will be used by the M9 to transfer to your computer, such as L0001234, that translates to 1234 actuations.
By Kenneth Wang on February 11, 2014