How big is the memory card of a SLR camera?

For 8G cards, it is best to use C4 or C6 memory cards. Memory cards marked C4 or C6 represent the reading and writing speed of the memory card. The reading and writing speed of C4 card is 4M/S, and the reading and writing speed of C6 card is 6M/S. An 8G memory card is enough for taking photos and videos. Characteristics of SD cards Class0: Including those lower than Class2 and not marked with SpeedClass; Class2: The reading and writing speed is not less than 2M/s, which can meet the needs of watching ordinary MPEG4MPEG2 movies, SDTV, and digital camera shooting; Class4: The reading and writing speed is not low More than 4M/s, it can smoothly play high-definition TV (HDTV), digital camera continuous shooting and other needs; Class6: read and write speed is not less than 6M/s, meeting the requirements of SLR camera continuous shooting and professional photography equipment.