NOTE: Generally, if a 1/2 shutter speed adjustment is indicated to negative lm, a full stop should be taken. When a reversal lm is being used, disregard the
8. Depth of Field
The area in acceptable sharpness in front of, and behind the subject in focus is called the depth of eld. The aperture selected and the distance of the subject as well as the focal length of a lens determines the depth of eld. Because of the long focal length of your lens, the depth of eld is narrow. For example, with a 800mm f8.0 lens, at a distance of 6 feet, the depth of eld is only 1/2 inch wide. It is recommended that you practice focusing with your lens before taking any serious pictures, especially in close up photography. Also, we recommend using a focus magnier to help determine the depth of eld sharpness under extreme conditions.