3.Lens at smallest aperture. Creat depth of field with subject, background and foreground in focus.
Using the Depth-of-Field Preview Button
The depth of field at taking aperture can be seen by depressing the depth-of-field preview button located on the front of the camera. When the button is pressed, the diaphragm closes down to the preselected taking aperture and the exact conditions of taking aperture and allows you to see how much background or foreground is in or out of focus. Depth of field can also be determined by referring to the color-coded scale printed on the lens barrel. The colored lines on either side of the main index mark (black arrow) correspond to different f/numbers which are engraved in corresponding colors. With the lens focused on a subject and set for a preselected aperture, depth of field can be read from the distance scale. For example, with the 50mm f/1.4 lens focused at 15 feet (4.5m) and used at a taking aperture of f/16, depth of field extends from approximately 8 feet ( 2.4m) to infinity.
caution: Do not release the shutter while the depth-of-field preview hutton is held down as this may result in the reflex mirror remaining in the locked-up position. If this should happen, the mirror
