Author Topic: Tonemapping - Plz Halp  (Read 79813 times)

2020-05-04, 23:57:21
Reply #180

lupaz

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Just tried Fstorm again - have the demo installed but its pain in the @ss on my gtx1060 - contrast does not affect saturation - awesome, reducing burn value does not make the image instantly dull, in fact it does not make the image dull at all - you can even go with negative value - again awesome.


This is true. I wish corona at least behaved as a real camera and I could take the rendering from corona as pure raw and do a camera raw in photoshop. I still couldn't figure how to do this.

2020-05-05, 02:10:56
Reply #181

agentdark45

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If it wasn't a typical Fstorm render, wouldn't you say you would have been able to notice?

Not only you didn't immediately notice but you even complained about the same things you are complaining about corona. And not only you, so maybe there is something else to it than objective observation.

Not sure why you label it as "tricked"  we are talking about comparisons and every serious study requires the elimination of variables.

I'm sorry you didn't like the results of the experiment, I bet that if the result was different and you actually noticed, you would have felt really good about that fact, and confirm your previous notions. So I think just because you didn't get the expected result, there is no reason to say "I did something to the Fstorm version".

Yeah, I'm not buying this. You're saying you went through the effort of purchasing a full Fstorm license, matching the watermark 1:1 in photoshop, and your "swapped" Fstorm render just happens to exhibit exactly the same grain pattern and concrete microdetail as your previous tests...
« Last Edit: 2020-05-05, 02:17:40 by agentdark45 »
Vray who?

2020-05-05, 02:19:10
Reply #182

Juraj

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Quote
contrast does not affect saturation

This one is bit unfair, Corona's Contrast is identical to Adobe's, it's basic contrast. It's not mistake that it doesn't operate on luminosity channel only, or offers selective smart saturation (Vibrance).
Some raw editors replaced Saturation with Vibrance (and call it Saturation again), but since we already have saturation, I would just add vibrance. The saturation is the weirdly integrated feature.. doesn't act like anything I know (affects luminosity&contrast way too much).

This is true. I wish corona at least behaved as a real camera and I could take the rendering from corona as pure raw and do a camera raw in photoshop. I still couldn't figure how to do this.

When people say they want Corona to behave like "camera", they actually want it to behave like raw converter. SOOC Jpegs from Camera are done by their own internal raw converter. The raw file itself is linear.

Corona's linear is also "raw", just 32bit floating point raw with massive dynamic range, which needs tonemapping. Even photos when merged into higher dynamic range require tonemapping, you can't just open them in Lightroom or CapturePro and use the base
Most raw converters don't allow these format at all, or they don't work correctly with them.

I once proposed devs what I consider could work as workaround. To allow Corona to save directly into .dng format. Adobe's DNG has both 16bit and 32bit floating point options. And I thought perhaps this would confuse raw editors less, effectively "trick" them.

But even right now it sort of "works". When you use "Open as" in Photoshop, you can open linear floating point (either 16bit or 32bit .exr/.hdr), and you will use absolutely the same workflow ACR would offer you if you loaded merged HDR photo. But you have to use the older process, or accept the odd behavior it can exhibit.
(I didn't test one more theory, if artificially clamping dynamic range before would make ACR more predictable).

The only thing Corona devs can do, is integrate different tonemapping curve (global tonemapper are always just curves). But it does work like camera, and you can export raw.


Whether Lolec is trolling or saying truth, it's genius post :- ).
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2020-05-05, 03:05:27
Reply #183

lolec

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Yeah, I'm not buying this. You're saying you went through the effort of purchasing a full Fstorm license, matching the watermark 1:1 in photoshop, and your "swapped" Fstorm render just happens to exhibit exactly the same grain pattern and concrete microdetail as your previous tests...

No, that would be silly!

I rendered a gray box in front of the Fstorm camera to get the raw watermark pattern. I then adjusted the brightness and used color burn to essentially revert what Fstorm is doing. I needed 3 layers to achieve that, as the shadow areas didn't quite work the same as the light areas.  Then I used that same "raw" Fstorm pattern and overlayed it to the Corona render version.

Here is a video of me turning on layers in photoshop :)  https://share.getcloudapp.com/WnuGqzoO

You can download the original image I posted and zoom in to see how much of a terrible job I did!

I know it can be hard to be confronted with information you don't like. But I have nothing to gain out of convincing anyone that Corona is better or worst, I'm a corona user! I want corona to be the best possible render engine! Actually, corona render is my main source of income now that I think of it... so NO I don't want it to stop improving!  BUT! I think it can improve more drastically by being easier to use and easier to achieve it's potential, than to extend it's potential even further. LETS DO BOTH, but lets do the easy one first!



2020-05-05, 09:40:18
Reply #184

bluebox

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Quote
contrast does not affect saturation

This one is bit unfair, Corona's Contrast is identical to Adobe's, it's basic contrast. It's not mistake that it doesn't operate on luminosity channel only, or offers selective smart saturation (Vibrance).
Some raw editors replaced Saturation with Vibrance (and call it Saturation again), but since we already have saturation, I would just add vibrance. The saturation is the weirdly integrated feature.. doesn't act like anything I know (affects luminosity&contrast way too much).


How is this unfair Juraj ? I converted a simple Corona playground scene of mine and when boosting contrast to 5 out of normall 1 my wood shaders started a new after psychedelic like life. They went to the moon with saturation. When doing the same in Fstorm the image remains visually 90% the same, only gets punchier.

I know you optimize your workflow and for sure you have some sort of a shader library of your own. This works great. Lets you streamline your workflow and become super efficient especially when incorporating triplanar wherever possible.
Only problem is that if you prepare your shaders in a controlled dedicated scene (say contrast 1) and then bring them to a more contrasty scene all of a sudden the colours break apart. This should not be the case.

Now, whether you call it saturation, vibrance or other is not important. If we get both controlls- contrast and saturation, imho contrast should operate only on luminosity, saturation should be saturation. And even saturation here does not work as it should - it shifts hue.

I agree that people wanting magicall "make dis shiet photoreal" button will get dissapointed because it will not happen as this comes from a lot of variables - working with references, matching colours etc. but lets just make the tools that we have work as they should. and upgrade the ones that are just bad at the moment - like HC, contrast, etc.

2020-05-05, 10:05:52
Reply #185

cjwidd

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Pretty curious how much of this conversation will even be relevant if the tonemapping options get overhauled for an upcoming version. Presumably we wouldn't be talking about contrast, highlight compression, etc. in the same way.

2020-05-05, 10:45:11
Reply #186

Juraj

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Because Corona Contrast is not part of tonemapping, it's grading tool and works correctly. Contrast 5 means 5 100 contrast modifiers in Photoshop.

It works the same in Photoshop, Lightroom & ACR.

VFB right now has small subset of post tools and ugly tonrmapper. That doesnt mean those post tools are wrong.
We dont need to copy every arbitrary decision someone else did.

Tool names are important, so yes ut matters how we call them. Contrast has nithing to do with anyones toxic looking shaders.
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2020-05-05, 11:25:50
Reply #187

MattiasD

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I really like these discussions. It`s maybe not always that constructive or correct, but it does always learn me new things.

@Juraj Talcik: Could you explain how to convert a linear (not tonemapped) image with aces? I downloaded OpenColorIO and Aces and tried to use this in photoshop, but I`m not sure what input and output i should choose from al the options and not even sure i should use photoshop at all for this :).

@lolec:
Here is my take on the scene:
Lut: Filmic Very High Contrast (log color space)


2020-05-05, 12:02:19
Reply #188

James Vella

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lol funny little trick you did there @lolec, and thanks for posting the scene it is an interesting challenge. I gave it a try in Vray keeping everything the same, textures, lighting, ev etc only swapped the camera for a physical but settings are same. Settings were as follows, default Vray, Vray + LUT Canon 300C, Vray/Aces. I think the LUT is actually pretty close to the Aces result but less range in the top end.
I think for Vray using the exposure control gives you a better result at EV 0 but for now we can ignore that.

Vray





Vray + LUT Canon 300C




Vray/Aces








LUT here:
https://cpn.canon-europe.com/content/news/canon_log_luts_now_available.do
BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube

2020-05-05, 12:08:32
Reply #189

Fluss

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James, did you convert your color textures / internal lights to ACEScg before rendering? If not your results are wrong. You need to put lin_srgb as the input (won't change that much except correcting color shifting)
« Last Edit: 2020-05-05, 12:12:55 by Fluss »

2020-05-05, 12:15:32
Reply #190

James Vella

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Yes you are correct Fluss. Textures are converted to aces cg space before rendering.



2020-05-05, 12:37:35
Reply #191

cjwidd

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@James Vella your post indicates the BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube LUT, but when I downloaded the LUT resources from the provided link, there are dozens of LUTS included. Why did you choose the BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0 version?

2020-05-05, 12:41:50
Reply #192

James Vella

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\canon-lut-201911\3dlut\65grid-3dlut\full-to-full-range\BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube

It doesnt give me the same result in Corona as Vray however.

edit (sorry I missed part of your question):
I chose it because there is only 3 to choose from as I need a log to rec709 df65 to match the setup of the corona scene. (6500kelvin).
- BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube
- BT709_CanonLog3-to-BT709_WideDR_65_FF_Ver.2.0.cube
- BT709_CanonLog-to-BT709_WideDR_65_FF_Ver.2.0.cube

The first one didnt have a vignette, so used that to keep things as clear as possible without adding additional parameters. Its how I work normally with the VFB, the more you play with the tone mapping controls (highlight burn, contrast etc) the more you complicate things when trying to compare results.






« Last Edit: 2020-05-05, 12:53:50 by James Vella »

2020-05-05, 12:52:47
Reply #193

Fluss

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Yes you are correct Fluss. Textures are converted to aces cg space before rendering.



And the sun and sky (internal Vray colorspace)?

2020-05-05, 13:00:39
Reply #194

agentdark45

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Here is a video of me turning on layers in photoshop :)  https://share.getcloudapp.com/WnuGqzoO

You can download the original image I posted and zoom in to see how much of a terrible job I did! [img width=1024 height=1187]https://i.imgur.com/SjeKjtJ.png/img]

I know it can be hard to be confronted with information you don't like. But I have nothing to gain out of convincing anyone that Corona is better or worst, I'm a corona user! I want corona to be the best possible render engine! Actually, corona render is my main source of income now that I think of it... so NO I don't want it to stop improving!  BUT! I think it can improve more drastically by being easier to use and easier to achieve it's potential, than to extend it's potential even further. LETS DO BOTH, but lets do the easy one first!

Haha fair play, I'll concede that I was indeed duped by this.
Vray who?