Question:

Why would you need a memory card for your digital camera?

Memory Options

Some digital cameras come with built-in memory, but it's nearly always very limited. Usually, a digital camera's built-in memory is only enough to shoot a few pictures at the camera's highest resolution setting.

But very few digital cameras don't include a memory card slot. There are several types of memory card, however, and only a handful of cameras can accept more than one type. So it's important to know what type of memory card your camera uses.

The most common memory cards are Compact Flash (CF), Secure Digital (SD), MultiMedia Card (MMC) and Sony's proprietary Memory Stick. Some Olympus and Fujifilm cameras use a proprietary memory card called xD. SD and MMC cards are often interchangable - check your camera's manual - but none of the other products are. Finally, there are SmartMedia (SM) cards, but no cameras using this type of card have been made since 2003.

One thing that these cards all have in common is how they store information: flash memory. But not all flash memory is created equal. For example, high-capacity SD cards (SDHC) - with capacities over 2 GB - only work in certain cameras. And CF cards come in Type I and Type II configurations. The Type II cards are thicker, and if your camera fits the thicker Type II cards, it can probably also use MicroDrives - tiny high-capacity hard drives.

SD and CF cards also offer different transfer speeds (the rate at which data is written from the camera to the memory card). If your camera's sensor is very high resolution, or if you need to shoot many pictures quickly - as with sports - a high-speed card can reduce the time between shots enough to make a difference for you.

Finally, consider capacity. When digital cameras shot 1MP (megapixel) photos, a 32 MB (megabyte) card was often enough memory for the average snapshooter. But with digital cameras now commonly offering resolutions of 10 MP and higher, even 1 GB (gigabyte) cards can fill up fast.

If your camera's top resolution is 5 MP or higher, you probably shouldn't bother with memory cards smaller than 1 GB, unless you routinely shoot at lower resolutions. But check your camera's manual before you invest in cards with capacities over 2 GB... some cameras don't work with high-capacity cards.