Alphashadows and fireflies on HDRI

[mbetke]

I'm fiddling around with HDRI maps (neverending story for me) and like usually I try different tricks to get rid of fireflies.
Now I figured out that if I use Pathtracing and click on "Alphashadow" I get a clean image. If I uncheck it they are very obvoiously.

If this a feature or not intended?

Attached two shots with and without at 1700 samples. Even at 5000 it didn't clean up before.
Using caustic blur = 1
HDRI gamma = 1,5 (makes lot of difference, but I loose sharp shadows although image is blurred a lot)
Power =0.7
IMportance sampling = on
No hotpix removal.

Please fix the little "imporantce_sampling" button. The text is cut of after the letter "l". Just minor I know.

[Karba]

I'm fiddling around with HDRI maps (neverending story for me) and like usually I try different tricks to get rid of fireflies.
Now I figured out that if I use Pathtracing and click on "Alphashadow" I get a clean image. If I uncheck it they are very obvoiously.

If this a feature or not intended?

Attached two shots with and without at 1700 samples. Even at 5000 it didn't clean up before.
Using caustic blur = 1
HDRI gamma = 1,5 (makes lot of difference, but I loose sharp shadows although image is blurred a lot)
Power =0.7
IMportance sampling = on
No hotpix removal.

Please fix the little "imporantce_sampling" button. The text is cut of after the letter "l". Just minor I know.

Current version has a bug with importance sampling. Sometimes it suddenly gets switched off.

[mbetke]

I just noticed. If I press the little update button it seems to be broken.
If I close the interactive window and reopen again the image clears after almost 500 samples. It is reproduceable.

Interesting is, if I check off the import-sampling the image renders darker.