Factors affecting the depth of focus
In photography, the depth of focus indicates a range of tolerance in the distance between the plane of the film (or sensor in digital cameras) and the rear lens element. This concept is sometimes confused with the (related but different) depth of field. The depth of focus generally is measured in hundredths of a millimeter.
depth of focus
The depth of focus depends on the same three factors affecting the depth of field. Indeed, the
depth of focus increases:
* If the aperture decreases
* If you increase the distance of the subject
* If you increase the focal length
the depth of focus decreases:
* If you increase the aperture
* If the subject distance decreases
* If the focal length decreases
A formula often used to calculate the approximate depth of focus is to multiply the focal length for the value of f-stop (aperture) and divide by 1000. For an exact calculation should be double the value of f-stops, multiply by the circle of confusion, and multiply by the value obtained by adding 1 to the magnification factor (magnification). The magnification factor depends on the focal length and adjusting the focus and can be difficult to obtain.