The Sony HDR-CX290 supports an SDXC memory card which is better than the SDHC memory card supported by most comparable spec camcorders that were released around the same time as it. This camcorder also support a Memory Stick (MS) and SD memory card. 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 camcorders that were released around the same time as the HDR-CX290.
The worst supported memory card type across similar types of video camera is MicroSDXC.
SDHC cards are DS cards with a higher capacity of up to 32GB.