Hi, I think what you have is the usual depth for field range characteristic of most lens. The usual proportion is 1/3 in front of the critcal plane and 2/3 behind, depending on the lens to subject distance. For close up , it is about 1:1 .tou can check thsiis out in the Kodak close up photography book I am reading now. This info is useful for working with wide apertures.
