Instead of recording images on film, digital cameras store pictures on memory cards. Your D600 uses a specific type of memory card — an SD card (for Secure Digital).
Most SD cards sold today carry the designation SDHC (for High Capacity) or SDXC (for eXtended Capacity), depending on how many gigabytes (GB) of data they hold. SDHC cards hold from 4GB to 32GB of data; the SDXC moniker is assigned to cards with capacities greater than 32GB.
To enable you to shoot oodles of pictures without having to swap out memory cards, the D600 has two memory-card slots. Open the cover on the right side of the camera, as shown in Figure 1-15, to reveal the slots. The top slot is Slot 1; the bottom slot is Slot 2.
The next section explains some details you need to know when you use two cards at a time, but first, here are some general guidelines for using SD cards:
With the camera turned off, place the card in the slot with the label facing the back of ...