On 11/3/20 7:29 AM, Le_Forgeron wrote:
> Le 31/10/2020 à 13:23, William F Pokorny a écrit :
> 
> How does it interact with bokey ?
> 
> Unclamping jitter is adding fuzziness, or it is bluriness ?
> 

I think jitter >>1  is more fuzzy than blurry, but hard to pick up a 
meaningful difference at times. Toward extremes, with everything way out 
of focus not sure there is much effective difference between wild 
sampling with focal blur and wild sampling with big jitter.

Thanks for the wonderful question! I've never used AA with focal blur... 
The latter usually being plenty of "AA." Didn't even think to "play" 
with the combination of the two features.

First to be clear my jitter changes affect only the jitter as used by AA 
methods 1 and 2. The focal blur internal jitter2d use is not changed.

Because I don't know how to use the bokeh feature, let me start with 
three initial compares in the attached image. For AA, when it is run, I 
am using +a0.0 +am1 +r4.

In the top row left is focal blur with no AA taking 7 seconds. In the 
middle top row is the same focal blur but turning on AA as above with 
jitter off. So the top row is comparing v3.8 master focal blur (7 
seconds elapsed) to focal blur with AA (2 minutes elapsed) and the 
difference at a 5x multiplier on the right.

In the middle row everything the same, except I turned on big jitter 
with +j44. Elapsed times basically the same. Differences are more 
dramatic as one might expect. I think one could say the middle column of 
the middle row now looks much more blurry/fuzzy than any of the others.

In the bottom row we have again focal blur on the left and in the bottom 
middle just AA with big jitter on at +j44 (13 seconds elapsed). Here I 
think we see that the jitter alone is more fuzzy than blurry.

I learned that AA with focal blur is much more expensive than either 
feature alone. Supposing the AA tends to mess up the convergence to 
whatever the confidence value is?

Even changing the AA threshold to a more reasonable 0.1 with jitter off 
increases the number of number of rays shot in a focal blur render:

4.2891e+06 -> 2.1576e+07 ---> 403.05%

I'll try and get back and do some bokeh renders this afternoon. Thanks 
again for the question!

Bill P.

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