Tag Properties
The following applies to Vector Motion Blur:
Strength is the degree of blurring. A value of 100% will blur the object for the entire distance between one frame and the next. For extra blurring, enter a value greater than 100%.
The following applies to Motion Blur in the Physical Renderer:
Here you define if an object should be rendered with Motion Blur (due to its change in position, rotation or size; this would reflect a No Deformation setting), with additional deformation blur (due to the effect of Deformers; Full Motion) or if any motion blur at all should be rendered.
With ProRender, only the motion blur can be enabled or disabled (note that the tag can also be assigned to a camera with which motion blur can be disabled).