An old rule of video photography says that you should include 'head room' around the top and sides of the frame so that if people move during the shot, their faces don't shift out of the picture. In still photography, close framing is perfectly acceptable and can even be dramatic. But eliminating all head room when capturing digital images can lead to a problem if you later want to print and frame the picture.

Digital cameras produce images that have a 4:3 aspect ratio (width relative to height), which matches that of a computer monitor or television. A 35mm film negative, on the other hand, produces images with a 3:2 aspect ratio, which is the same as for a 4x6-inch photo frame. A 5x7-inch frame has an aspect ratio of 5:7; an 8x10-inch frame, 4:5.

When you enlarge a 35mm film image to a 5x7 or 8x10, the photo lab must either crop the picture or add a white border to account for the difference in aspect ratio between the original and the enlargement. You must make the same decision if you want to mount your digital image in any of the commercially available frame sizes (or mattes), at least until manufacturers get wise and start producing frames with a 4:3 aspect ratio.

If you don't leave a little head room (left), you must either crop away a portion of the subject's face (middle) or reduce the image size and add a border (right) if you want to make the picture fit a 4x6-inch photo frame.

As an example, consider the figure above. The left image is the digital original; the middle image shows what part of the picture would remain if cropped to the 4x6-inch aspect ratio. At this aspect ratio, part of the toddler's head must be cropped away. Your other option is to reduce the original and add a border, as shown in the right image.

The moral of the story: To avoid having to lose part of your subject's face or add an unsightly border, always leave a decent margin of head room when you're shooting digital portraits.

Of course, another way to solve the problem is to take your digital prints to a framing store and buy a custom-cut matte or frame. But you can save yourself the expense and hassle by simply getting in the habit of allowing adequate head room for all your portraits.

TIP: Some digital cameras now offer a special 3:2 format setting in addition to the standard 4:3 format. This option limits you to capturing an area that has a 3:2 aspect ratio, a feature that's especially useful when you're shooting pictures that you know you want to frame.