You know when a photo gradually gets more “blurry” as the distance from the camera increases? That’s the Depth of Field. Here is a better way to describe it.
“Depth of field is the range of distance around the focal plane which is acceptably sharp. The depth of field varies depending on camera type, aperture and focusing distance, although print size and viewing distance can influence our perception of it.”
To better fully understand, and calculate the depth of field, for your camera – take a look at this tutorial from Cambridge in Colour.
Via: Dan Rubin on Ma.gnolia.