Almost all cameras use removable memory cards to store photos and video. A few smaller devices use fixed in-built memory instead, but these are relatively rare. Memory card types Memory cards come in many different types, though many have slowly been phased out and others are very specialised. The most common type is the SD/SDHC/SDXC […]
U1/U3 card
This is a speed rating used for memory cards that confirm to the UHS ultra high speed data transfer bus on better-specified SD cards. U1 corresponds roughly to a class 10 card on the regular SD bus, or a sustained transfer speed of 10MB/s, while U3 is a faster standard capable of a sustained write speed of 30MB/s. These are not to be confused with UHS-I and UHS-II, which are different memory card designs, not different speed ratings.