Corona exposure/ gi problem

[jasonvdp]

Hi everyone,
I'm having a problem with my exposure / Gi.
-I render with simple exposure at 2 and my image looks as it should.
-I render with my simple exposure at 10 and of course it is overblown - I hit stop and lower the simple exposure to 2 and it is different then my original render at 2. it is darker.

Troubleshooting this problem, I have got rid of any hdri/ corona sky and I am just using a white background in my scene environment.
I have defaulted all my materials but still cant find a solution.
As far as I am concerned the simple exposure is in the tonemapping under "post" so this should yield the same result.
I have also concluded that if I lower my msi to 0, I don't have this problem anymore but this should not happen.

So my attached images show
1. an image with the tonemapping, simple exposure at 2
2. an image with the tonemapping exposure at 10 at time of render THEN lowered to 2.

Anybody having this issue? Any suggestions

[TomG]

Sounds like the note at the end of https://support.chaos.com/hc/en-us/articles/4528455281681-How-to-change-exposure-during-rendering- ?

[maru]

This is expected due to the small bias that Corona introduces (Max Sample Intensity) - https://support.chaos.com/hc/en-us/articles/4528530828689
One workaround is to disable MSI in the Performance tab (set it to 0) or increase it to a very high value instead. This will however increase render times (introduce more noise/fireflies).