digital still cameras

Memory Cards

Digital still cameras can store images on a variety of different media types, such as SmartMedia, CompactFlash, and Sony's MemoryStick. Some cameras even burn images to CD on the fly, or utilize small hard drives to store images. The CompactFlash format has emerged as the most popular storage media.

Flash cards come in different sizes measured in megabytes, such as 64 MB, 128 MB, 512 MB, 1GB, or 2GB. These cards can store hundreds of images at medium resolution (a resolution good enough for publication on a Web site).

How many images can fit onto a memory card? The answer to this question isn't nearly as cut-and-dried as it with traditional film. Factors include:

  1. The capacity of the memory card
  2. The image resolution at which you choose to shoot
  3. The amount of "compression" applied to the stored images

For a rough sense of how many images can fit onto a 512MB Compact Flash card at a few of the above combinations, see the table below:

Image storage capacity for 512 MB CF card
Resolution Compression Images
L format 3456 x 2304 Fine 137
L format 3456 x 2304 Medium 277
M format 2496 x 1664 Fine 237
M format 2496 x 1664 Medium 452
S format 1728 x 1152 Fine 410
S format 1728 x 1152 Medium 780
RAW @ 3456 x 2304 None 57

We'll discuss resolution and compression in more detail later in this guide. Meanwhile, don't be tempted to set your camera to the smaller formats and compression ratios just to squeeze more images onto a card. Memory cards and hard drives are cheap -- even if you only intend to shoot for the web, you never know when the bureau chief might ask for a high resolution version for special purposes, or you decide you'd like to have a printable version. You can always remove data from an image, but you can't restore data that was never there to begin with. For general purposes, we like to shoot at Medium format (2496 x 1664), Fine or Medium compression. Professional photographers use resolutions much higher than this.

Inserting the Memory Card

The camera will have a slot into which you insert the flash card, generally on the right side of the camera. Place your thumb on the black arrow on the slot labeled CF OPEN and slide the small door to the slot in the direction of the arrow.

Swing open the door and insert the CompactFlash card into the slot, with the label facing toward the camera back and the arrow on the card pointing in. Push the card gently until it snaps into place. Then close the door until it clicks into place.

If the card does not fit easily into the slot, do not force it. There are tiny pins inside the slot that can be bent or broken if a card is inserted forcefully.

To remove the card, repeat the steps above for opening the card slot and then press down on the button to the right of the slot to release the card.