2008

The effect of changing duration.
Samples Determines how many Duration Subdivision copies are sampled.
The maximum setting is 32.
When Samples is less than Duration, random sampling within the duration
occurs (which is why there might be a slight granular look to the motion blur).
For example, if Duration Subdivision=12 and Samples=8, there are eight
random samples out of 12 possible copies within each frame.
When Samples=Duration, there is no randomness (and if both numbers are
at their maximum value (32), you get a dense result (which costs between 3–4
times the normal rendering time for that specific object).
If you want to obtain a smooth blur effect, use the maximum settings of 32/32.
If you want to cut down rendering time, values of 12/12 will give you much
smoother results than 16/12.
Because sampling happens within the duration, the Duration value always
has to be less than or equal to Samples.
Duration Subdivisions Determines how many copies of each object are
rendered within the Duration.
5958 | Chapter 18 Rendering