Depth of field vs resolution

摘要

ONE THING that always exasperated me at school was that, just as I had grasped some indisputable law, whether it governed the conjugation of French verbs or how chemical ions bond, we would immediately be informed of a raft of exceptions and conditions that appeared to break it. At the time I failed to appreciate that my teachers were passing on information in easily assimilated chunks - I just thought they were trying to confuse me and wished they'd tell me the truth from the outset. I'm sure that fledgling photographers must feel a similar sense of frustration when, having grasped the concept of using a smaller aperture to produce greater depth of field and that greater depth of field means sharper images, some smart aleck brings up the subject of diffraction.