Focus effects

This technique correctly models the behavior of light by calculating the volumes through which light propagates. Objects are rendered by projecting their surface area through a focal point onto a lens for each pixel. Objects that are "out-of-focus" appear fuzzy. Objects
that are extremely close to the lens (like the lens aperture in a camera) when the focal point is far away affect the entire image by reducing brightness.

For example, when you look through a window screen from close range, you can either focus on the objects outside the window or you can focus on the screen itself. If you focus on the objects outside the window, the screen seems to disappear (see Figure 1.1a). If
you focus on the screen, the objects outside disappear (see Figure 1.1b).


Figure 1.1a


Figure 1.1b

The following image demonstrates how the focus affects close and distance objects. The three images are of three rectangles, one black rectangle close to the lens, one red rectangle (the same size as the black rectangle) a small distance from the lens, and a third
green rectangle that is larger and at a great distance.


(This image was generated with custom code.)