Tonemapping - Plz Halp

[cjwidd]

^this scene seems to be really driven by the materials and the modeling, although the tonemapping is obviously driving home a pretty specific look. Great project, of course, pretty sure it was on the Corona Renderer installer splash screen for a while.

[lupaz]

I have bought this Bertrand Benoit scene ( see attachment ) and many of his cameras have 0.5 HC. This makes them much more realistic.

I think this would be something that I'd think  a client would accept in terms of overall brightness:
(credit: Danthree.com)

[Designerman77]

Take a look at this also made in Corona ( you probably seen it already)
https://www.behance.net/gallery/42186689/Apoco77-House

What is similar to Bertrands scene is extreme highlight burn from outside ( by going under 1 HC ) . This however gives this dynamic range inside that is IMO worth the trade. And this burn can be bypassed by corona tonemap control texture map.

I agree. That's worth the trade!
Such a good base is worth spending some more minutes in post, too in order to get rid of the excessive burning.

[James Vella]

@Fluss, I gave you settings a go and I found at EV0 you are correct, they look similar. Things start to go pear shaped when you hit -5 +3 (for the sRGB/Highlight Compression). Whats your take on this, I miss something?

Vray HDRI Aces





Vray HDRI sRGB + Curve/Highlight Compression

[Fluss]

James, leave the VFB exposure at 0 and increase your render exposure by 3 EVs (so let's say from iso 1600 to iso 12800 in camera settings) and see what happens.

edit:  render exposure was limited by Max Ray intensity.

[Fluss]

I made it for you:

Vray + curve + HC - ISO 1600 :



Vray + curve + HC - ISO 12800 :



edit : 3EVs at render time should match 3EVs in VFB, it does not in Vray (Vray 5 beta here)

[Fluss]

Now here is the interesting part. Made the same test with Corona - photographic exposure - same settings as Vray.

Corona + curve + HC - ISO 1600



Corona + curve + HC - ISO 12800

[James Vella]

hmm ok I understand what you mean, but this requires re-rendering. As with the ACES workflow you can adjust the exposure and get the range you need without blowing out areas, similar to how you would work with a photograph in lightroom.

[Fluss]

hmm ok I understand what you mean, but this requires re-rendering. As with the ACES workflow you can adjust the exposure and get the range you need without blowing out areas, similar to how you would work with a photograph in lightroom.

No, this will happen with ACES too. Look at your ACES example, it's also washed out.  Vray and Corona renders are not exposed the same

[James Vella]

This is probably a terrible example as I dont do indoor photography (and the snow doesnt help) but this is almost the same expectation of results that I got with the aces test. Exposure stops, -5, -2, 0, +3, +5

[Fluss]

Here is what we will consider default exposure for this comparison :

Vray - ACES TM - ISO1600



Now, which of those two renders do you consider correct? Corona is correct

Vray - ACES TM - ISO1600 - +3EV VFB



Vray - ACES TM - ISO12800 (+3EV rendering) - +0EV VFB



I personally made my choice.

edit : after some more thoughts, removed some too early conclusions
edit2 : here is what has been removed. Decided to finally keep it to open the discussion, might be false assumptions :

Now if you look at corona 12800 ISO, it looks like it is not calculating real scene exposure but a base exposure which is then multiplied (like the results we get by increasing exposure in VFB). I'm not really sure what is happening here but that could be an explanation. -> Vray exposure is limited by max ray intensity


Corona - CURVE + 8HC 12800ISO

[James Vella]

hmm, neither do to be honest.

I just took a photo of a room in the house as a raw photo and took it into lightroom:

Exposure: 0


Exposure: 1.5


Exposure: 3.0


The problem Im seeing is the light behaviour is actually quite similar to the fstorm render tests a couple pages back (potentially the default bloom was effecting the result). Where as I see the highlight areas in these last renders as dull in comparison.

I think your last Corona render is probably the best of all 3. I find this quite interesting, ill have to think about this a bit more for awhile.

[Fluss]

Of course it's dull, we're using ACES to compress highlights like crazy. Adding some quick crazy bloom and glare help. Still, there is something strange with the corona exposure in my opinion. ->it's good

[Fluss]

Well, always though Vray and corona photographic exposure settings would match but after quickly looking at it a bit closer, it does not seems to be the case. I'll try to dig a bit further if I find time. The corona one seems to make more sense at first sight.

edit: confirmed, Vray exposure is wrong limited by MRI, corona is good. So pointless comparison from the start between corona and Vray, forget my posts

Guys, checking the technical side is crucial in those kinds of comparisons, so as explaining the process... Everybody was taking a conclusion on renders with different lighting.... That sucks.

If you are looking for me, I'm hiding. 😂

[lupaz]

Is it even possible to match every technical aspect between render engines anyway?