The JVC GY-HM850 supports an SDXC memory card which is better than the SDHC memory card supported by most similar spec camcorders that were released around the same time as it. SDXC cards are SD cards but with a much higher capacity and faster processing speeds. They have a maximum capacity of 2TB (Terabytes).
An SDXC memory card is actually the best supported memory card type amongst all video cameras that came out in the last 12 months.
Amongst similar types of camcorder the worst supported memory card type is SD.
SDHC cards are DS cards with a higher capacity of up to 32GB.