<P> The focus spread is related to the depth of focus . Ray ( 2000 , 56 ) gives two definitions of the latter . The first is the tolerance of the position of the image plane for which an object remains acceptably sharp ; the second is that the limits of depth of focus are the image - side conjugates of the near and far limits of DOF . With the first definition , focus spread and depth of focus are usually close in value though conceptually different . With the second definition , focus spread and depth of focus are the same . </P>
<P> The focus spread is related to the depth of focus . Ray ( 2000 , 56 ) gives two definitions of the latter . The first is the tolerance of the position of the image plane for which an object remains acceptably sharp ; the second is that the limits of depth of focus are the image - side conjugates of the near and far limits of DOF . With the first definition , focus spread and depth of focus are usually close in value though conceptually different . With the second definition , focus spread and depth of focus are the same . </P>
the main factor affecting depth of focus is the
the main factor affecting depth of focus is the
the image - side conjugates of the near and far limits of DOF
the image - side conjugates of the near and far limits of DOF