In an earlier posting I talked about the benefits using selective focus and a shallow depth of field. Depth of field is the near-to-far distance in a scene that is in acceptably sharp focus. There are three factors that contribute to how much depth of field a shot will have: lens focal length, lens aperture and distance to your subject. All other things being equal, a wider lens (shorter focal length) and a smaller aperture create more near-to-far sharpness.
One fast and easy way to get a lot of depth of field is to put your camera in the "landscape" exposure mode. In this mode the camera automatically selects the smallest possible aperture giving the amount of existing light and the ISO you have set. (The camera will also try to select a shutter speed that is safe for hand holding.) In this rural Iowa scene, for instance, I wanted to keep everything from the grass in the foreground to the distant hills in sharp focus. I could have taken manual exposure readings and then choosing the smallest available aperture--and that's usually what I do. But there are times when I'm just taking a quick snap of a pretty scene and in those circumstances, I simply flip the camera to its landscape mode and shoot.
Read your manual for more info about these specialty exposure modes (often called "scene" modes in manuals); they can provide some very useful technical shortcuts.
1 hour ago