Depth of Fied and Circle of Confusion
The definition of Depth of Field (DoF) from Wikipedia says that it is “the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image“. It relies on the notion of “acceptable sharpness” which is based on a criteria called the ”Circle of Confusion” (CoC). This article explains the essential about the criteria of sharpness and DoF.
A photograph is exactly sharp only on the focus plane, and more or less blur around it. The transition between little blur and definitely blur is gradual, so where do we determine the limit of acceptable sharpness that defines the Depth of Field (DoF)?