Relevant to Blender v2.31
<filter type="antinoise" name="Anti Noise" radius = "1.000000" max_delta = "0.100000"> </filter>
processes the rendered image, reducing noise resulting from too few
pathlight, hemilight, or conetraced samples.
name: Name of the filter
radius: Amount of blur to
apply to the areas considered to have noise.
max_delta: Tolerance setting for noise. With higher
values, more of the image will be considered 'noise' and will have
the blur applied to them.
<filter type="dof" name="dof" focus = "12.5" near_blur ="10.000000" far_blur ="10.000000" scale ="2.000000"> </filter>
type-dof: Post processes
the rendered image, using depth information to apply an out of focus
name: Name of the filter.
focus: Distance from the
camera that is in focus (objects further away and closer than this
point will be out of focus).
near_blur: Amount to blur
objects in front of the focus point.
far_blur: Amount to blur
objects behind the focus point.
scale: Scales the area that is in focus. Higher values
will decrease the effect of depth of field as the out of focus areas
are pushed away from the focus area.
The Depth of Field filter is a 2D filter, i.e. a post processing technique, and as such, has advantages and disadvantages. It uses the rendered image, plus a Z Buffer (which tells the filter how far away each pixel is from the camera) to figure out which pixels are blurred or not blurred.
Because its a 2D effect it has the advantage of being extremely quick. However there are a few disadvantages:
Reflections are not blurred correctly. If you look at a reflection, you'll notice that the reflection's blur is based on the distance from the camera of the reflection plane, not the object in the reflection.
Because the DOF is done on a 2D image, rather than a 3D scene, the blur cannot know what is behind any given object, therefore often the edges of an extremely blurred object in the foreground will look smudgy or dirty.
If you keep these limitations in mind, the Depth of Field filter can produce great looking Depth of Field effects very quickly.