If you plan on capturing 4k UHD video on an internal SD card be sure to get a good one. Otherwise you will get error messages.
SanDisk Extreme PRO 64GB UHS-1/U3 SDXC Memory Card Up To 95MB/s & 4K Ultra HD-Ready, Frustration-Free- SDSDXPA-064G-AFFP
amazon link: http://www.amazon.com/SanDisk-Extreme...
Class 10 U3 - this card is great for use with the Panasonic FZ1000, GH4 and Sony camcorders that record 4k video.