HDR and bit depth

[elecman]

How many bits (Dynamic Range, f-Stops) does Octane use to render an image? It seems to suffer from the same problem described below. I want my indoor render to look like what a human eye sees, not some cheap disposable camera, HDR wise. The location where the sun shines on the floor is totally white. If I turn down the exposure, everything else becomes very dark.



Source:
https://www.blenderguru.com/tutorials/s ... otorealism

Further reading:
http://davidnew.net/site/2013/11/20/hdr ... ifference/

[Maikel]

Hi elecman,

I suspect you are running into the boundaries of what the Octane Imager provides, rather than Octane not seeing enough color information. If your image is too dark, and bumping exposure / highlight compression does not get the trick done, try raising the Gamma value a little. You should not have to put in very extreme numbers to see a noticeable change.

If you are still running into issues that the grading tools in Octane itself cannot solve, the best path to an external pipeline is exporting your rendered result as 16-bit EXRs, that way all color information is retained for later processing.

[acc24ex]

again hitting the same issue as discussed here - octane team people - did you even look at this and can we replicate the same result with octane as it is or do we require this filmic color response - I feel it's having a too low of a dynamic range and image always looks darker or blownout and have to use tricks to get it there
.. I think you should really consider this issue
https://www.blenderguru.com/tutorials/s ... otorealism

[elecman]

So nobody knows how many f-stops of dynamic range Octane uses? If this is too low, no fiddling with gamma will fix it. Exporting an image and modifying with a 3rd party program is a really, really bad hack.

[bepeg4d]

Hi elecman,
please, have a look at this article by roeland:
viewtopic.php?f=21&t=33214
and the new features of 3.08 with custom LUT support:
viewtopic.php?f=33&t=63219
ciao beppe

[elecman]

Thanks for the links. I read it but it still doesn't answer the question of how many f-stops of dynamic range Octane uses.

[icelaglace]

If I understand right, you basically want Octane to support HDR color space workflow inside the engine itself without having to export an EXR and process the color space to something else ?

Because that's basically what the "Filmic" thing you posted is doing by using OpenColorIO.
You can do the same but you have to use external tools like Photoshop or Lightroom to control your image.

Octane isn't limited to bits or "f-stops", Octane tonemaps the image to current generation monitors i.e 8 bits. But the engine itself is rendering in a wide color spectrum so there aren't really specific amount of dynamic ranges.
10 bits HDR monitors are spreading slowly though but standards are all over the place at the moment. (ACES, etc...)

If I am wrong, please enlighten me with what you mean. Thanks

[elecman]

Yes, I am looking for an HDR color space workflow inside the engine itself. Imagine saving a video with a broken workflow like that. It would be nice if this is on the roadmap.

[Goldorak]

Yes, I am looking for an HDR color space workflow inside the engine itself. Imagine saving a video with a broken workflow like that. It would be nice if this is on the roadmap.

If you save linear exr it shouldn’t lose any data. We could add any tone mapping system to the imager node (in theory OSL shader for LUT might also be flexible enough to cover this, will investigate).

[elecman]

Thanks for considering