Mastering Shadows
By Olivier Saraja

S  t  e  p   5 :
Samples
In the previous renderings (BufSi set to 512, SpotSi set to 60.00 degrees) we can see that the shadows are smooth, but perhaps not enough. Before trying to increase the BufSi, we will try to set the number of samples to a higher value.
 
BufSi set to 512, SpotSi set to 60.00 degrees and Samples set to 3
Zoom: The shadow is quite acceptable
BufSi set to 512, but SpotSi set to 60.00 degrees and Samples set to 5
Zoom: The borders have been anti-aliased

It is very hard to tell the difference between Samples 3 and Samples 5 at first, but looking at the zoom closely, it becomes obvious that the borders of the shadows have been smoothed. In fact, Samples behaves the way OSA does.