Camera cards are formatted with a FAT32 file system, which is the most common on digital cameras. The first card slot holds the primary card, which is usually a large SD card.
The second card slot is for a spare card, in case the primary card fails. .
Most digital cameras also have an internal memory that can be used to store pictures. However, if the internal memory runs out of space, pictures can still be transferred to a spare SD card using the second card slot.
The second card slot is also useful for capturing video. By inserting a third card into the camera, it can be used as a secondary storage device for videos.
This allows for simultaneous capturing of pictures and videos, which can be helpful in situations where time is of the essence.