Depth of Field
Enable Depth of Field
Enables the shader.
Focal Plane is the distance to the focal plane from the camera, i.e. a point at this distance from the camera is completely in focus.
Radius of Confusion
This is an actual measurement in scene units, and for a real-world camera this is approximately the radius of the iris, i.e. it depends on the cameras f-stop. But it is a good rule of thumb to keep it on the order of a couple of centimeters in size (expressed in the current scene units), otherwise the scene may come out unrealistic and be perceived as a minature.
Samples defines how many rays are shot. Fewer is faster but grainier, more is slower but smoother.
When bias is 1.0, the circle of confusion is sampled as a uniform disk. Lower values push the sample probability towards the center, creating a "softer" looking DOF effect with a more "misty" look. Higher values push the sample probability towards the edge, creating a "harder" looking DOF where bright spots actually resolve as small circles.
One can also set the angle with the blade angle parameter, which is expressed such that 0.0 is zero degrees and 1.0 is 360 degrees.
When the scene uses motion blur, controls the number of times the material is shaded during each time interval (set by Shutter Duration). Range=0 to 100. Default=5. By default, the material is shaded only once, and then blurred. If the material changes rapidly during the shutter interval, it might be useful to increase this value, in order to obtain more accurate motion blur. Rapid changes in reflections or refractions might require a higher Time Samples value.
Use custom Bokeh Map
The use bokeh parameter enables the user of a specific bokeh map. When this parameter is used, the parameters bias, blade count and blade angle have no effect.
The map defines the shape of the DOF filter kernel, so a lled white circle on a black background is equivalent to the standard blur. Generally, one need more samples to accurately "resolve" a custom bokeh map than the built-in bokeh shape, which has an optimal sampling distribution.
The RGB-Maps is for simulate the "Chromatic Aberration" effect.