Hi!

I'm using Bokeh on a render of a ground with a perfectly black sky. After the Bokeh, the top of the image becomes bright. It looks like its picking the bottom pixels to calculate the bokeh of the top pixels.

Is there a way to control what the border pixel blurs with? Setting it to repeat, black, streak, etc. ?

Bookeh COP just respects the layer's border settings

depending on what you want to affect you can either change those where the layer was created (File COP, Layer COP, ... )
or if those are set to default you can change Default Border settings on the COPnet

or just surgically use Layer Properties COP right before the Bookeh COP and change the border setting to Clamp or whatever you want