HDRI and Yarfay DOF trial

As the subject said - trying to learn HDRI and Yafray DOF rendering. Any suggestions on the little white sparks around the highlights.
Settings - GI method -Full, Quality - best, depth-2, CDepth-1, AA passes-6, AA Samples-25.


You seem to have a pretty good handle on it! Although the metal looks a little pinched in one area, but that may be because of the lighting. Are there any tutorials for learning this? I think it would be nice to know. The white specs may be a result of using photons? I have had some strange results using them for GI.