There is with rendering of some elements - dynamic hair and when using depth-of-field being two examles. Typically I wouldn't expect to get great results with DOF with a pixel sample setting of 5 or less - I've gone as high as 14 for a couple of overnight renders where I've really wanted smooth results.

 

PoserPro2014(Sr4), Win7 x64, display units set to inches.

                                      www.danielroseartnew.weebly.com