Depth of Field

Web. Photograph by Tom Atwood.

When you hear photographers talk about "depth of field," what they really mean is what is and isn't in focus in a photograph. Often, what's not in focus is just as important. In this photo of a tiny spider web along Fruit Road near Interstate 55, if the background grass and brush were sharp, it would be difficult to see the detail of the web. Opening the lens wide (the camera's aperture) creates a shallow depth of field, meaning not much will be in focus. Anything in front of the web (closer to the lens) or behind it (farther away) will be soft. That's often exactly what a photographer wants, so that the subject--in this case the web--stands out. Shutter: 1/125; Aperture: f/5.6; ISO: 200; Focal length: 42 mm.