When you photograph a moving subject, whether it's a jump-roping child or a splashing waterfall, the shutter speed determines how sharply focused that subject appears.

• A fast shutter speed stops motion, so the subject appears to be still.
• At a slow shutter speed, a moving object appears blurred.

Shutter-speed controls vary depending on the camera's sophistication (and, unfortunately, price). If your camera doesn't offer manual shutter control or shutter-priority autoexposure but does offer scene assist modes, try these tricks to affect shutter speed:

• To capture motion cleanly, look for an Action scene assist mode. This mode tells the camera to use its fastest possible shutter speed.
• No Action mode? Try using Portrait mode, if that's available. In this mode, the camera uses its largest aperture. In bright light, the large aperture forces the camera to dial in a fast shutter speed to properly expose the photo.
• To blur motion, give Landscape mode a try. This mode selects a small aperture, which usually has the effect of forcing a slower shutter speed.