up min aa subdivs.
Actually you need to use lower Min shading rate for this as your primary rays are responsible for cleaning this kind on noise. Use something like 3 for min shading rate..
Min subdivs 1
Max subdivs 50
noise threshold .008
GI,
Primary, BF
Secondary, LC default settings ,then change subdivs to 2000
This seems like the type of area that comes up a lot that could use a bit of smart denoising or some other kind of less accurate cheat, especially for areas that bloom?
this kind of highlite might be coming from dome hdr, if it is you can’t really fix it easily other then paint it out in the hdr just a thought tho.
The highlight is coming from the interior lights on the rear view mirror. I excluded them now from this object, because otherwise I just couldn’t get it clean. Tried all the settings mentioned here.
Try different hdri´s. Try ticking “sub pixel mapping”. Lower intensity of reflected lights. Change specular addition in option.
I think those paths are of the class of “high energy, low probability” (read: nasties.).
Meaning you’ll likely have to resort to ancillary techniques (SPM,clamping of secondaries/primaries, soft roll-off of highlights, turning the paths to non-caustic ones, resorting to post effects on the offending lights, f.e.), as there is not going to be a set of “pure” sampling values which will clean them up properly.
This isn’t an issue with us alone either: i’ts very much at the forefront of research in the rendering literature, worldwide.
Try Mitsuba, for example, and see how many different integrators and samplers it brings to bear to solve precisely this class of issues, and with which results (in speed and quality both.).
any chance for a simple scene with the issue?
so far I can’t get bokeh so noisy.
edit:
ok, got it..
how about blasting the bokeh with fixed sampler and 100 subdivs?
if its all bright light sources (ibl or regular lights) than maybe you are using this old trick with using exponential color mapping for sampling but keeping the image in linear color? just a wild guess here.
For me there is too much trickery involved in that solution.
Lele do you think that it’d be possible to group samples based on luminance / COC radius around the source point and feed those into a defocus / averaging technique to smooth out? We likely know the bokeh we’re aiming for so is there any theory to blur / average while aiming for that known disc shape?
That’s a question for @vlado.
The idea of batching and sorting isn’t new (see Hyperion, f.e.), and i was reading a paper i can’t recall whom from not a week ago on the blurring of ray directions to improve sampling, so you may be on to something, you clever old chap! 
.
Old at least
if you’re old, what must the rest of us say then?
One way to make this easier on the renderer is to make the reflection slightly blurry. I’m thinking of experimenting with automatic adjustment of the glossiness based on the distance to the camera and the defocus amount. This slight change will not be obvious in most cases, but will help to clean up the bokeh faster. The idea is very similar to texture filtering, but applied to reflection glossiness.
Best regards,
Vado
Ooh! Oliver could almost try that now on his silvers with a falloff map using his camera target as it’s reference object!
That’s a good idea actually. Will try that.
