Using the Right Focal Length to Take Pictures with Your Digital Camera
Different digital camera lenses have different focal lengths. On a digital camera, focal length measures the distance between the lens and the image sensor (in millimeters). Focal length determines the camera lens’s depth of field and the size at which your subject appears in the frame (as shown in this figure):
Standard: Most point-and-shoot cameras come with a focal length in the neighborhood of 35mm. This focal length is appropriate for the kinds of snapshots most people take.
Wide-angle: Lenses that have short focal lengths. A short focal length has the visual effect of making the subject appear smaller and farther away from you.
Telephoto: Lenses that have long focal lengths. A long focal length seems to bring the subject closer to you and increases the subject’s size in the frame.
Cameras that offer a zoom lens enable you to vary focal length. When you zoom in, the focal length increases; when you zoom out, it decreases.
A few cameras come with specialty focal-length features:
Dual lenses: Usually provide both a standard, snapshot-oriented focal length and a telephoto focal length.
Macro mode: Permits close-up photography.