ABSTRACT
DoF is an important rendering effect. A real camera lens focuses on a single plane in the scene. Images of objects in that plane are perfectly sharp. Images of objects closer to or farther from the camera are blurry. Of course, most objects are typically outside the exact plane of focus. Photographers recognize that each point on an out-of-focus object blurs into the shape of the camera aperture, which is usually a disk, octagon, or hexagon. They call the bounding circle of a blurred point the circle of confusion (CoC) of that point. They say that an object is in focus (for a digital image) when the radius of the CoC is half a pixel or less. In that case, the object does not appear blurred because the blur falls below the image resolution. Photographers refer to the depth range over which the CoC radius is less than half a pixel as the focus field. They refer to the extent of this range as the depth of field. In computer graphics, that phrase is now associated with the effect of blurring images of objects outside of the field.
