Bryan Peterson's Understanding Photography Field Guide

The smaller the f-stop number, the larger the lens opening; the larger the f-stop, the smaller the lens opening.

Now, set the aperture to f/22 and focus on something that’s approximately 5 feet from the lens. Then, if you’re in Manual exposure mode, adjust your shutter speed until the camera’s light meter indicates a correct exposure and shoot. If you’re in Aperture Priority mode, simply shoot, since the camera will set the shutter speed for you.

Most photographers aren’t inclined to think of the wide-angle lens as a close-up lens, but if they did, their images would improve tenfold.

With a 12–24mm zoom lens, it’s the 12–16mm focal range. With 18–55mm, 18–70mm, 17–35mm, or 20–35mm lenses, you’ll only call on the 17–18mm range.

First, you must turn off the autofocus.